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Sample records for enso packaging asi

  1. Distinct persistence barriers in two types of ENSO: PERSISTENCE BARRIERS OF TWO ENSO TYPES

    SciTech Connect

    Ren, Hong-Li; Jin, Fei-Fei; Tian, Ben

    El Niño–Southern Oscillation (ENSO) is usually subject to a persistence barrier (PB) in boreal spring. This study quantifies the PB and then reveals its distinct features in the two types of ENSO, the eastern Pacific (EP) and central Pacific (CP) types. We suggest that the PB of ENSO can be measured by the maximum rate of autocorrelation decline of Niño sea surface temperature anomaly (SSTA) indices. Results show that the PB of ENSO generally occurs in boreal late spring to early summer in terms of Niño3.4 index, and the EP ENSO has the PB in late spring, while the CPmore » type has the PB in summer. By defining an index to quantify PB intensity of ENSO, we find that the CP ENSO type features a much weaker PB, compared to the EP type, and the PB intensity of equatorial SSTAs is larger over the EP than the western Pacific and the far EP.« less

  2. Distinct persistence barriers in two types of ENSO: PERSISTENCE BARRIERS OF TWO ENSO TYPES

    DOE PAGES

    Ren, Hong-Li; Jin, Fei-Fei; Tian, Ben; ...

    2016-10-30

    El Niño–Southern Oscillation (ENSO) is usually subject to a persistence barrier (PB) in boreal spring. This study quantifies the PB and then reveals its distinct features in the two types of ENSO, the eastern Pacific (EP) and central Pacific (CP) types. We suggest that the PB of ENSO can be measured by the maximum rate of autocorrelation decline of Niño sea surface temperature anomaly (SSTA) indices. Results show that the PB of ENSO generally occurs in boreal late spring to early summer in terms of Niño3.4 index, and the EP ENSO has the PB in late spring, while the CPmore » type has the PB in summer. By defining an index to quantify PB intensity of ENSO, we find that the CP ENSO type features a much weaker PB, compared to the EP type, and the PB intensity of equatorial SSTAs is larger over the EP than the western Pacific and the far EP.« less

  3. Different impacts of mega-ENSO and conventional ENSO on the Indian summer rainfall: developing phase

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Wu, Zhiwei; Zhou, Yefan

    2016-04-01

    Mega-El Niño-Southern Oscillation (ENSO), a boarder version of conventional ENSO, is found to be a main driving force of Northern Hemisphere summer monsoon rainfall including the Indian summer rainfall (ISR). The simultaneous impacts of "pure" mega-ENSO and "pure" conventional ENSO events on the ISR in its developing summer remains unclear. This study examines the different linkages between mega-ENSO-ISR and conventional ENSO-ISR. During the developing summer of mega-El Niño, negative rainfall anomalies are seen over the northeastern Indian subcontinent, while the anomalous rainfall pattern is almost the opposite for mega-La Niña; as for the conventional ENSO, the approximate "linear opposite" phenomenon vanishes. Furthermore, the global zonal wave trains anomalous are found at mid-latitude zones, with a local triple circulation pattern over the central-east Eurasia during mega-ENSO events, which might be an explanation of corresponding rainfall response over the Indian Peninsula. Among 106-year historical run (1900-2005) of 9 state-of-the-art models from the Coupled Model Inter-comparison Project Phase 5 (CMIP5), HadGEM2-ES performs a promising skill in simulating the anomalous circulation pattern over mid-latitude and central-east Eurasia while CanESM2 cannot. Probably, it is the models' ability of capturing the mega-ENSO-ISR linkage and the characteristic of mega-ENSO that make the difference.

  4. New adaptive statistical iterative reconstruction ASiR-V: Assessment of noise performance in comparison to ASiR.

    PubMed

    De Marco, Paolo; Origgi, Daniela

    2018-03-01

    To assess the noise characteristics of the new adaptive statistical iterative reconstruction (ASiR-V) in comparison to ASiR. A water phantom was acquired with common clinical scanning parameters, at five different levels of CTDI vol . Images were reconstructed with different kernels (STD, SOFT, and BONE), different IR levels (40%, 60%, and 100%) and different slice thickness (ST) (0.625 and 2.5 mm), both for ASiR-V and ASiR. Noise properties were investigated and noise power spectrum (NPS) was evaluated. ASiR-V significantly reduced noise relative to FBP: noise reduction was in the range 23%-60% for a 0.625 mm ST and 12%-64% for the 2.5 mm ST. Above 2 mGy, noise reduction for ASiR-V had no dependence on dose. Noise reduction for ASIR-V has dependence on ST, being greater for STD and SOFT kernels at 2.5 mm. For the STD kernel ASiR-V has greater noise reduction for both ST, if compared to ASiR. For the SOFT kernel, results varies according to dose and ST, while for BONE kernel ASIR-V shows less noise reduction. NPS for CT Revolution has dose dependent behavior at lower doses. NPS for ASIR-V and ASiR is similar, showing a shift toward lower frequencies as the IR level increases for STD and SOFT kernels. The NPS is different between ASiR-V and ASIR with BONE kernel. NPS for ASiR-V appears to be ST dependent, having a shift toward lower frequencies for 2.5 mm ST. ASiR-V showed greater noise reduction than ASiR for STD and SOFT kernels, while keeping the same NPS. For the BONE kernel, ASiR-V presents a completely different behavior, with less noise reduction and modified NPS. Noise properties of the ASiR-V are dependent on reconstruction slice thickness. The noise properties of ASiR-V suggest the need for further measurements and efforts to establish new CT protocols to optimize clinical imaging. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  5. High performance a-Si solar cells and new fabrication methods for a-Si solar cells

    NASA Astrophysics Data System (ADS)

    Nakano, S.; Kuwano, Y.; Ohnishi, M.

    1986-12-01

    The super chamber, a separated UHV reaction-chamber system has been developed. A conversion efficiency of 11.7% was obtained for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method. As a new material, amorphous superlattice-structure films were fabricated by the photo-CVD method for the first time. Superlattice structure p-layer a-Si solar cells were fabricated, and a conversion efficiency of 10.5% was obtained. For the fabrication of integrated type a-Si solar cell modules, a laser pattering method was investigated. A thermal analysis of the multilayer structure was done. It was confirmed that selective scribing for a-Si, TCO and metal film is possible by controlling the laser power density. Recently developed a-Si solar power generation systems and a-Si solar cell roofing tiles are also described.

  6. Optimized Varian aSi portal dosimetry: development of datasets for collective use.

    PubMed

    Van Esch, Ann; Huyskens, Dominique P; Hirschi, Lukas; Baltes, Christof

    2013-11-04

    Although much literature has been devoted to portal dosimetry with the Varian amorphous silicon (aSi) portal imager, the majority of the described methods are not routinely adopted because implementation procedures are cumbersome and not within easy reach of most radiotherapy centers. To make improved portal dosimetry solutions more generally available, we have investigated the possibility of converting optimized configurations into ready-to-use standardized datasets. Firstly, for all commonly used photon energies (6, 10, 15, 18, and 20 MV), basic beam data acquired on 20 aSi panels were used to assess the interpanel reproducibility. Secondly, a standardized portal dose image prediction (PDIP) algorithm configuration was created for every energy, using a three-step process to optimize the aSi dose response function and profile correction files for the dosimetric calibration of the imager panel. An approximate correction of the backscatter of the Exact arm was also incorporated. Thirdly, a set of validation fields was assembled to assess the accuracy of the standardized configuration. Variations in the basic beam data measured on different aSi panels very rarely exceeded 2% (2 mm) and are of the same order of magnitude as variations between different Clinacs when measuring in reference conditions in water. All studied aSi panels can hence be regarded as nearly identical. Standardized datasets were successfully created and implemented. The test package proved useful in highlighting possible problems and illustrating remaining limitations, but also in demonstrating the good overall results (95% pass rate for 3%,3 mm) that can be obtained. The dosimetric behavior of all tested aSi panels was found to be nearly identical for all tested energies. The approach of using standardized datasets was then successfully tested through the creation and evaluation of PDIP preconfigured datasets that can be used within the Varian portal dosimetry solution.

  7. Where was ENSO strongest?

    NASA Astrophysics Data System (ADS)

    Cane, M. A.; Chen, D.; Kaplan, A.

    2008-12-01

    Mark A. Cane, Dake Chen, Alexey Kaplan The description of this session begins: "Historical SST records suggest that for the past three decades, ENSO has been anomalously strong" and goes on to ask why. In this talk we dispute this interpretation of the historical record from within the historical record. In particular, we suggest that the most "anomalously strong" period in the historical ENSO record is the late nineteenth century. This claim requires a discussion of how we measure "ENSO strength". We also speculate on possible reasons for the strength of ENSO in this earlier period. Finally, we consult the models, and in reiteration of the collective conclusion of all speakers at this session, find that the riddles the models provide are inelegant and disobliging, lacking the cryptic wisdom of the classical oracles.

  8. ENSO influences the onset of violent conflicts

    NASA Astrophysics Data System (ADS)

    Meng, K. C.; Hsiang, S. M.

    2009-12-01

    Climatic changes are frequently cited as a possible external driver of violent conflict in human societies. Qualitative studies suggest that climatic shifts may stress populations and be conducive to violent conflict. Statistical evidence has shown that anomalous local rainfall is correlated with the onset of conflict. This study finds that in addition to idiosyncratic weather events, climatic states also play a role in triggering violent conflict. El Niño Southern Oscillation (ENSO), the semi-periodic, oceanic Kelvin wave in the tropical Pacific, induces remote temperatures in the tropical free troposphere to rise. This ``ENSO teleconnection'' is not globally uniform and is felt most strongly in the tropical regions during the boreal winter. To determine the degree in which country-level climatic conditions are affected by ENSO, an absolute correlation measure between surface temperature and two ENSO indices was calculated for every country for the period 1949-2009. Countries with high levels of correlation are labeled “ENSO affected,” while countries with low correlation are labeled “ENSO unaffected”. Thus, historical variation in ENSO serves as a ``natural experiment'': if the state of ENSO influences conflict onset, it should be apparent for ENSO affected countries but not for unaffected countries. Using the UCDP/PRIO Armed Conflict Dataset, we find evidence of a large and statistically significant influence of ENSO on the onset of violent conflict. Between 1949-2009, the average probability of a conflict beginning in any country was 0.03. For the ENSO affected countries, we find that a 1°C rise in either NINO12 or NINO34 is associated with an increased probability of conflict onset by 0.015 (or 50% of the global country average). A relationship was not detected for the ENSO unaffected group of countries. This result is robust to a range of statistical models. Nonparametric methods (see figure) also indicate a marked difference in the response of ENSO

  9. Monsoon-Enso Relationships: A New Paradigm

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    This article is partly a review and partly a new research paper on monsoon-ENSO relationship. The paper begins with a discussion of the basic relationship between the Indian monsoon and ENSO dating back to the work of Sir Gilbert Walker up to research results in more recent years. Various factors that may affect the monsoon-ENSO, relationship, including regional coupled ocean-atmosphere processes, Eurasian snow cover, land-atmosphere hydrologic feedback, intraseasonal oscillation, biennial variability and inter-decadal variations, are discussed. The extreme complex and highly nonlinear nature of the monsoon-ENSO relationship is stressed. We find that for regional impacts on the monsoon, El Nino and La Nina are far from simply mirror images of each other. These two polarities of ENSO can have strong or no impacts on monsoon anomalies depending on the strength of the intraseasonal oscillations and the phases of the inter-decadal variations. For the Asian-Australian monsoon (AAM) as a whole, the ENSO impact is effected through a east-west shift in the Walker Circulation. For rainfall anomalies over specific monsoon areas, regional processes play important roles in addition to the shift in the Walker Circulation. One of the key regional processes identified for the boreal summer monsoon is the anomalous West Pacific Anticyclone (WPA). This regional feature has similar signatures in interannual and intraseasonal time scales and appears to determine whether the monsoon-ENSO relationship is strong or weak in a given year. Another important regional feature includes a rainfall and SST dipole across the Indian Ocean, which may have strong impact on the austral summer monsoon. Results are shown indicating that monsoon surface wind forcings may induce a strong biennial signal in ENSO and that strong monsoon-ENSO coupling may translate into pronounced biennial variability in ENSO. Finally, a new paradigm is proposed for the study of monsoon variability. This paradigm provides

  10. Image quality comparison of two adaptive statistical iterative reconstruction (ASiR, ASiR-V) algorithms and filtered back projection in routine liver CT.

    PubMed

    Chen, Li-Hong; Jin, Chao; Li, Jian-Ying; Wang, Ge-Liang; Jia, Yong-Jun; Duan, Hai-Feng; Pan, Ning; Guo, Jianxin

    2018-06-06

    To compare image quality of two adaptive statistical iterative reconstruction (ASiR and ASiR-V) algorithms using objective and subjective metrics for routine liver CT, with the conventional filtered back projection (FBP) reconstructions as reference standards. This institutional review board-approved study included 52 patients with clinically suspected hepatic metastases. Patients were divided equally into ASiR and ASiR-V groups with same scan parameters. Images were reconstructed with ASiR and ASiR-V from 0 (FBP) to 100% blending percentages at 10% interval in its respective group. Mean and standard deviation of CT numbers for liver parenchyma were recorded. Two experienced radiologists reviewed all images for image quality blindly and independently. Data were statistically analyzed. There was no difference in CT dose index between ASiR and ASiR-V groups. As the percentage of ASiR and ASiR-V increased from 10 to 100% , image noise reduced by 8.6 -57.9% and 8.9-81.6%, respectively, compared with FBP. There was substantial interobserver agreement in image quality assessment for ASiR and ASiR-V images. Compared with FBP reconstruction, subjective image quality scores of ASiR and ASiR-V improved significantly as percentage increased from 10 to 80% for ASiR (peaked at 50% with 32.2% noise reduction) and from 10 to 90% (peaked at 60% with 51.5% noise reduction) for ASiR-V. Both ASiR and ASiR-V improved the objective and subjective image quality for routine liver CT compared with FBP. ASiR-V provided further image quality improvement with higher acceptable percentage than ASiR, and ASiR-V60% had the highest image quality score. Advances in knowledge: (1) Both ASiR and ASiR-V significantly reduce image noise compared with conventional FBP reconstruction. (2) ASiR-V with 60 blending percentage provides the highest image quality score in routine liver CT.

  11. What Controls ENSO-Amplitude Diversity in Climate Models?

    NASA Astrophysics Data System (ADS)

    Wengel, C.; Dommenget, D.; Latif, M.; Bayr, T.; Vijayeta, A.

    2018-02-01

    Climate models depict large diversity in the strength of the El Niño/Southern Oscillation (ENSO) (ENSO amplitude). Here we investigate ENSO-amplitude diversity in the Coupled Model Intercomparison Project Phase 5 (CMIP5) by means of the linear recharge oscillator model, which reduces ENSO dynamics to a two-dimensional problem in terms of eastern equatorial Pacific sea surface temperature anomalies (T) and equatorial Pacific upper ocean heat content anomalies (h). We find that a large contribution to ENSO-amplitude diversity originates from stochastic forcing. Further, significant interactions exist between the stochastic forcing and the growth rates of T and h with competing effects on ENSO amplitude. The joint consideration of stochastic forcing and growth rates explains more than 80% of the ENSO-amplitude variance within CMIP5. Our results can readily explain the lack of correlation between the Bjerknes Stability index, a measure of the growth rate of T, and ENSO amplitude in a multimodel ensemble.

  12. Understanding multidecadal variability in ENSO amplitude

    NASA Astrophysics Data System (ADS)

    Russell, A.; Gnanadesikan, A.

    2013-12-01

    Sea surface temperatures (SSTs) in the tropical Pacific vary as a result of the coupling between the ocean and atmosphere driven largely by the El Niño - Southern Oscillation (ENSO). ENSO has a large impact on the local climate and hydrology of the tropical Pacific, as well as broad-reaching effects on global climate. ENSO amplitude is known to vary on long timescales, which makes it very difficult to quantify its response to climate change and constrain the physical processes that drive it. In order to assess the extent of unforced multidecadal changes in ENSO variability, a linear regression of local SST changes is applied to the GFDL CM2.1 model 4000-yr pre-industrial control run. The resulting regression coefficient strengths, which represent the sensitivity of SST changes to thermocline depth and zonal wind stress, vary by up to a factor of 2 on multi-decadal time scales. This long-term modulation in ocean-atmosphere coupling is highly correlated with ENSO variability, but do not explain the reasons for such variability. Variation in the relationship between SST changes and wind stress points to a role for changing stratification in the central equatorial Pacific in modulating ENSO amplitudes with stronger stratification reducing the response to winds. The main driving mechanism we have identified for higher ENSO variance are changes in the response of zonal winds to SST anomalies. The shifting convection and precipitation patterns associated with the changing state of the atmosphere also contribute to the variability of the regression coefficients. These mechanisms drive much of the variability in ENSO amplitude and hence ocean-atmosphere coupling in the tropical Pacific.

  13. ENSO controls interannual fire activity in southeast Australia

    NASA Astrophysics Data System (ADS)

    Mariani, M.; Fletcher, M.-S.; Holz, A.; Nyman, P.

    2016-10-01

    El Niño-Southern Oscillation (ENSO) is the main mode controlling the variability in the ocean-atmosphere system in the South Pacific. While the ENSO influence on rainfall regimes in the South Pacific is well documented, its role in driving spatiotemporal trends in fire activity in this region has not been rigorously investigated. This is particularly the case for the highly flammable and densely populated southeast Australian sector, where ENSO is a major control over climatic variability. Here we conduct the first region-wide analysis of how ENSO controls fire activity in southeast Australia. We identify a significant relationship between ENSO and both fire frequency and area burnt. Critically, wavelet analyses reveal that despite substantial temporal variability in the ENSO system, ENSO exerts a persistent and significant influence on southeast Australian fire activity. Our analysis has direct application for developing robust predictive capacity for the increasingly important efforts at fire management.

  14. Air-temperature variations and ENSO effects in Indonesia, the Philippines and El Salvador. ENSO patterns and changes from 1866-1993

    NASA Astrophysics Data System (ADS)

    Harger, J. R. E.

    The major features in development of the "El Nino-Southern Oscillation" (ENSO) involve oscillation of the Pacific ocean-atmosphere in an essentially unpredictable (chaotic) fashion. The system moves between extremes of the so-called "warm events" lasting one or two years and involving movement of warm sea water from the western Pacific along the equator to impact on the west coast of the American continent and "cold-events" associated with easterly trade-wind-induced flows of colder water from the eastern Pacific towards the west. Historical data indicate that ENSO years as experienced by the Island of Java are either much warmer than non-ENSO years or only slightly, if at all, warmer than normal (non-ENSO) years. Hot-dry years within the ENSO warm event cycle are almost always followed by cooler wet years and vice versa. This pattern also extends to include the year immediately following the terminal year of an ENSO warm event set. The initial year of an ENSO warm event set may be either hot with a long dry season or relatively cool (nearer to the temperature of a non-ENSO year) and having a short dry season. In recent years, since 1950, of the 9 ENSO warm events, the initial year tends to have been hot and dry for 6 (1951, 1957, 1963, 1972, 1982, 1991) and neutral or cool and wet for 3 (1968, 1976, 1986). An area of 88,000 ha burned in 1991 (Jakarta Post 30 November 1991) largely in Kalimantan in association with the 1991-1992 ENSO event, an extensive pall of smoke developed over Kalimantan, Singapore and Malaysia during September-October of 1991. Surface vegetation-based fires continued to burn in East Kalimantan as of 29 April 1992 and extended into the 1992 dry season, in response to the ENSO conditions carrying forward from 1991. The increasing annual trend in air-temperature exhibited by the mean monthly values over the period 1866-1993, for the Jakarta and the Semarang data taken together is 1.64°C (0.0132°C per year from 25.771 to 27.409°C). The major

  15. Influence of ENSO Modoki on Colombia Precipitation

    NASA Astrophysics Data System (ADS)

    Rojo Hernandez, J. D.; Mesa, O. J.; Gómez Ríos, S.; Martinez Pérez, K.

    2015-12-01

    In recent years, multiple observations reported contrasting effects in climate patterns around the world, due to differential warming patterns in tropical regions of Pacific Ocean during ENSO warm and cold events. Several authors have proposedthe concept that these variations are part of a new type of El Niño-Southern Oscillation (ENSO) named as "Modoki". Using the classification of periods as Canonical or Modoki ENSO proposed by Tedeschi et al. (2013) we discriminatedthe quarterly mean values of precipitation in Colombia since 1975 to 2006 in order to analyze the rainfall behavior during El Niño Modoki (ENM) and La Nina Modoki (LNM), and contrast them with Canonical El Niño and La Niña (ENC-LNC) effects. The observations show that for the precipitation in Colombia, ENSO Modoki effects are different from Canonical ENSO effects, producing in general opposite climatic conditions between ENC and ENM, as well as between LNC and LNM. In other regions, the ENSO Modoki produces anomalies with the same sign that ENC, but with lower intensity. R. G. Tedeschi, I. F. Cavalcanti, and A. M. Grimm. Influences of two types of ENSO on Southamerican precipitation. International Journal of Climatology, 33(6):1382-1400, 2013.

  16. The ASI Science Data Center

    NASA Astrophysics Data System (ADS)

    Gendre, B.; Giommi, P.

    2010-12-01

    The ASI Science Data Center (ASDC, www.asdc.asi.it), a facility of the Italian Space Agency (ASI) is a multi-mission science operations, data processing and data archiving center that provides support to several scientific space missions. At the moment the ASDC has significant responsibilities for a number of high-energy astronomy/astroparticle satellites (e.g. Swift, AGILE, Fermi, NuSTAR and AMS) and supports at different level other missions like, Herschel and Planck. The ASDC was established in 2000 based on the experience built with the management of the BeppoSAX Science Data Center. It is located at the ESA site of ESRIN in Frascati, near Rome (Italy).

  17. Tridacna Derived ENSO Records From The Philippines During The Last Interglacial Show Similar ENSO Activity To The Present Day

    NASA Astrophysics Data System (ADS)

    Welsh, K.; Morgan, Z.; Suzuki, A.

    2016-12-01

    Although modeled predictions for the relative strength and frequency of ENSO under mean warming conditions suggest an increase in the number and strength of ENSO event, however there are limited seasonally resolved records of ENSO variability during previous warm periods for example the last interglacial to test these models as reliable archives such as corals are not generally well preserved over these time periods. Presented here are two multi decadal Tridacna gigas derived stable isotopic time series from a coral terrace on the island of Cebu in the Philippines that formed during MIS5e based upon geomorphology and open-system corrected U/Th dating of corals. The ENSO activity observed in these time well preserved records indicate a similar level of ENSO activity during the last interglacial period as the present day based upon comparisons with recent coral derived stable isotopic records. Though these are relatively short records they provide further windows into ENSO activity from this important time period and demonstrate this area may be provide more opportunities to gather these archives.

  18. Modification of ENSO and ENSO-related atmospheric characteristics due to future climate change

    NASA Astrophysics Data System (ADS)

    Matveeva, Tatiana; Gushchina, Daria

    2017-04-01

    The El Niño/Southern Oscillation (ENSO) is the strongest natural climate interannual fluctuation in Tropical Pacific, it affects regional and global climate. There are two types of this phenomenon: East Pacific (EP) El Niño characterized by maximum of SST anomalies centered over the eastern tropical Pacific and Central Pacific (CP) El Niño with SST warming in the center of the Pacific Ocean [Ashok et al., 2007; Kug et al., 2009]. The ability of CMIP5 coupled ocean-atmosphere general circulation models (CGCMs) to simulate two flavors of El Niño correctly was estimated using EOF-analysis technique of SST anomalies [Takahashi et al., 2011] in the recent studies [Matveeva and Gushchina, 2016]. It was shown that only several CGCMs were able to reproduce two types of ENSO. The ENSO-related characteristics can alter due to global climate change. However, scientific community can't be sure whether ENSO activity will be enhanced or damped under global warming. In this study, we choose the 6 "best" CGCMs (BNU-ESM, CCSM4, CNRM-CM5, FIO-ESM, INM-CM4, MIROC5) which simulated spatial and temporal features of the two types of El Niño the most realistic way. To obtain a complete result we analyzed anomalies of complex ENSO-related characteristics (SST, rainfall, vertical movement, atmospheric circulation in the upper and lower troposphere) during two types of El Niño events. We compared the spatial distribution of these anomalies depending future climate scenarios (we took two scenarios with significant differences - RCP 2.6 and RCP 8.5 [Taylor et al., 2012]). It was shown the large difference in model's estimates ENSO-related anomalies' changes for future climate. The main aspect of this study is the analysis of the ENSO characteristics' modification (frequency, amplitude, the ratio between EP and CP El Niño) under different scenarios of warming. We didn't expect any significant change of frequency for two types of El Nino. It was shown that there was no well

  19. A hierarchy of models for ENSO flavors in past climates.

    NASA Astrophysics Data System (ADS)

    Karamperidou, C.; Xie, R.; Di Nezio, P. N.

    2017-12-01

    The existence of two distinct ENSO flavors versus an ENSO continuum remains an open question. Investigating the response of ENSO diversity to past climate forcings provides a framework to approach this question. Previous work using GCMs has shown that ENSO flavors may respond differentially to mid-Holocene orbital forcing, with a significant suppression of Eastern Pacific ENSO as opposed to insensitivity of Central Pacific ENSO. Here, we employ a hierarchy of models to explore the robustness of ENSO-flavor response to orbital forcing. First, we use a modified version of the Zebiak-Cane model which simulates two ENSO modes reminiscent of ENSO flavors. We find a quasi-linear response of these two modes to orbital forcing corresponding to 6ka, 111ka, and 121ka BP in terms of growth rates, frequency and spatial pattern of SST anomalies. We then employ an Earth System Model subject only to orbital forcing to show the corresponding response in the three past climates. This investigation indicates that no extratropical influences may be required to produce such quasi-linear ENSO-flavor response to orbital forcing. Aided by paleoclimate proxies, the hierarchy of models employed here presents a paleoclimate perspective to the fundamental and elusive question of the nature and origins of ENSO diversity.

  20. Tree growth response to ENSO in Durango, Mexico

    NASA Astrophysics Data System (ADS)

    Pompa-García, Marin; Miranda-Aragón, Liliana; Aguirre-Salado, Carlos Arturo

    2015-01-01

    The dynamics of forest ecosystems worldwide have been driven largely by climatic teleconnections. El Niño-Southern Oscillation (ENSO) is the strongest interannual variation of the Earth's climate, affecting the regional climatic regime. These teleconnections may impact plant phenology, growth rate, forest extent, and other gradual changes in forest ecosystems. The objective of this study was to investigate how Pinus cooperi populations face the influence of ENSO and regional microclimates in five ecozones in northwestern Mexico. Using standard dendrochronological techniques, tree-ring chronologies (TRI) were generated. TRI, ENSO, and climate relationships were correlated from 1950-2010. Additionally, multiple regressions were conducted in order to detect those ENSO months with direct relations in TRI ( p < 0.1). The five chronologies showed similar trends during the period they overlapped, indicating that the P. cooperi populations shared an interannual growth variation. In general, ENSO index showed correspondences with tree-ring growth in synchronous periods. We concluded that ENSO had connectivity with regional climate in northern Mexico and radial growth of P. cooperi populations has been driven largely by positive ENSO values (El Niño episodes).

  1. Tree growth response to ENSO in Durango, Mexico.

    PubMed

    Pompa-García, Marin; Miranda-Aragón, Liliana; Aguirre-Salado, Carlos Arturo

    2015-01-01

    The dynamics of forest ecosystems worldwide have been driven largely by climatic teleconnections. El Niño-Southern Oscillation (ENSO) is the strongest interannual variation of the Earth's climate, affecting the regional climatic regime. These teleconnections may impact plant phenology, growth rate, forest extent, and other gradual changes in forest ecosystems. The objective of this study was to investigate how Pinus cooperi populations face the influence of ENSO and regional microclimates in five ecozones in northwestern Mexico. Using standard dendrochronological techniques, tree-ring chronologies (TRI) were generated. TRI, ENSO, and climate relationships were correlated from 1950-2010. Additionally, multiple regressions were conducted in order to detect those ENSO months with direct relations in TRI (p < 0.1). The five chronologies showed similar trends during the period they overlapped, indicating that the P. cooperi populations shared an interannual growth variation. In general, ENSO index showed correspondences with tree-ring growth in synchronous periods. We concluded that ENSO had connectivity with regional climate in northern Mexico and radial growth of P. cooperi populations has been driven largely by positive ENSO values (El Niño episodes).

  2. ENSO effects on stratospheric ozone: A nudged model perspective

    NASA Astrophysics Data System (ADS)

    Braesicke, Peter; Kirner, Oliver; Versick, Stefan; Joeckel, Patrick

    2015-04-01

    The El Niño/Southern Oscillation (ENSO) phenomenon is an important pacemaker for interannual variability in the Earth's atmosphere. ENSO impacts on ozone have been observed and modelled for the stratosphere and the troposphere. It is well recognized that attribution of ENSO variability is important for trend detection. ENSO impacts in low latitudes are easier to detect, because the response emerges close (temporally and spatially) to the forcing. Moving from low to high latitudes it becomes increasingly difficult to isolate ENSO driven variability, due to time-lags involved and many other modes of variability playing a role as well. Here, we use a nudged version of the EMAC chemistry-climate model to evaluate ENSO impacts on ozone over the last 35 years. In the nudged mode configuration EMAC is not entirely free running. The tropospheric meteorology is constrained using ERA-Interim data. Only the upper stratosphere and the composition (including ozone) are calculated without additional observational constraints. Using lagged correlations and supported by additional idealised modelling, we describe the ENSO impact on tropospheric and stratospheric ozone in the EMAC system. We trace the ENSO signal from the tropical lower troposphere to the polar lower and middle stratosphere. Instead of distinguishing tropospheric and stratospheric responses, we present a coherent approach detecting the ENSO signal as a function of altitude, latitude and time, and demonstrate how a concise characterisation of the ENSO impact aids improved trend detection.

  3. Heartbeat of the Southern Oscillation explains ENSO climatic resonances

    NASA Astrophysics Data System (ADS)

    Bruun, John T.; Allen, J. Icarus; Smyth, Timothy J.

    2017-08-01

    The El Niño-Southern Oscillation (ENSO) nonlinear oscillator phenomenon has a far reaching influence on the climate and human activities. The up to 10 year quasi-period cycle of the El Niño and subsequent La Niña is known to be dominated in the tropics by nonlinear physical interaction of wind with the equatorial waveguide in the Pacific. Long-term cyclic phenomena do not feature in the current theory of the ENSO process. We update the theory by assessing low (>10 years) and high (<10 years) frequency coupling using evidence across tropical, extratropical, and Pacific basin scales. We analyze observations and model simulations with a highly accurate method called Dominant Frequency State Analysis (DFSA) to provide evidence of stable ENSO features. The observational data sets of the Southern Oscillation Index (SOI), North Pacific Index Anomaly, and ENSO Sea Surface Temperature Anomaly, as well as a theoretical model all confirm the existence of long-term and short-term climatic cycles of the ENSO process with resonance frequencies of {2.5, 3.8, 5, 12-14, 61-75, 180} years. This fundamental result shows long-term and short-term signal coupling with mode locking across the dominant ENSO dynamics. These dominant oscillation frequency dynamics, defined as ENSO frequency states, contain a stable attractor with three frequencies in resonance allowing us to coin the term Heartbeat of the Southern Oscillation due to its characteristic shape. We predict future ENSO states based on a stable hysteresis scenario of short-term and long-term ENSO oscillations over the next century.Plain Language SummaryThe Pacific El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) nonlinear oscillator phenomenon has a far reaching influence on the climate and our human activities. This work can help predict both long-term and short-term future <span class="hlt">ENSO</span> events and to assess the risk of future climate hysteresis changes: is the elastic band that regulates the <span class="hlt">ENSO</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.7366W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.7366W"><span>Impacts of <span class="hlt">ENSO</span> on global hydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ward, P. J.; Eisner, S.; Flörke, M.; Kummu, M.</p> <p>2012-04-01</p> <p>The economic consequences of flooding are huge, as exemplified by recent major floods in Thailand, Pakistan, and Australia. Moreover, research shows that economic losses due to flooding have increased dramatically in recent decades. Whilst much research is being carried out to assess how this may be related to socioeconomic development (increased exposure to floods) or climate change (increased hazard), the role of interannual climate variability is poorly understood at the global scale. We provide the first global assessment of the sensitivity of extreme global river discharge to the El Niño Southern Oscillation (<span class="hlt">ENSO</span>). Past studies have either: (a) assessed this at the local scale; or (b) assessed only global correlations between <span class="hlt">ENSO</span> and mean river discharge. Firstly, we used a daily observed discharge dataset for 622 gauging stations (from the GRDC database), and assessed and mapped correlations and sensitivities between these time-series and several indices of <span class="hlt">ENSO</span>. We found that, on average, for the stations studied <span class="hlt">ENSO</span> has a greater impact on annual high-flow events than on mean annual discharge, especially in the extra-tropics. However, the geographical coverage of the dataset is poor in some regions, and is highly skewed towards certain areas (e.g. North America, Europe, and eastern Australia). This renders a truly global assessment of <span class="hlt">ENSO</span> impacts impossible based on these observed time-series. Hence, we are also using a modelling approach to estimate correlations and sensitivities in all basins, gauged and ungauged. For this, we are using a gridded time-series of modelled daily discharge from the EU-WATCH project, and analysing relationships between these time-series (per grid-cell) and indices of <span class="hlt">ENSO</span>. This allows for the first truly global assessment of the impact of <span class="hlt">ENSO</span> variability on river discharge; these analyses are ongoing. Of course, this approach entails its own problems; the use of global hydrological models to derive daily discharge time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeoRL..3911704K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeoRL..3911704K"><span>The two types of <span class="hlt">ENSO</span> in CMIP5 models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Seon Tae; Yu, Jin-Yi</p> <p>2012-06-01</p> <p>In this study, we evaluate the intensity of the Central-Pacific (CP) and Eastern-Pacific (EP) types of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) simulated in the pre-industrial, historical, and the Representative Concentration Pathways (RCP) 4.5 experiments of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Compared to the CMIP3 models, the pre-industrial simulations of the CMIP5 models are found to (1) better simulate the observed spatial patterns of the two types of <span class="hlt">ENSO</span> and (2) have a significantly smaller inter-model diversity in <span class="hlt">ENSO</span> intensities. The decrease in the CMIP5 model discrepancies is particularly obvious in the simulation of the EP <span class="hlt">ENSO</span> intensity, although it is still more difficult for the models to reproduce the observed EP <span class="hlt">ENSO</span> intensity than the observed CP <span class="hlt">ENSO</span> intensity. Ensemble means of the CMIP5 models indicate that the intensity of the CP <span class="hlt">ENSO</span> increases steadily from the pre-industrial to the historical and the RCP4.5 simulations, but the intensity of the EP <span class="hlt">ENSO</span> increases from the pre-industrial to the historical simulations and then decreases in the RCP4.5 projections. The CP-to-EP <span class="hlt">ENSO</span> intensity ratio, as a result, is almost the same in the pre-industrial and historical simulations but increases in the RCP4.5 simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4212239','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4212239"><span>Salinity anomaly as a trigger for <span class="hlt">ENSO</span> events</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhu, Jieshun; Huang, Bohua; Zhang, Rong-Hua; Hu, Zeng-Zhen; Kumar, Arun; Balmaseda, Magdalena A.; Marx, Lawrence; Kinter III, James L.</p> <p>2014-01-01</p> <p>According to the classical theories of <span class="hlt">ENSO</span>, subsurface anomalies in ocean thermal structure are precursors for <span class="hlt">ENSO</span> events and their initial specification is essential for skillful <span class="hlt">ENSO</span> forecast. Although ocean salinity in the tropical Pacific (particularly in the western Pacific warm pool) can vary in response to El Niño events, its effect on <span class="hlt">ENSO</span> evolution and forecasts of <span class="hlt">ENSO</span> has been less explored. Here we present evidence that, in addition to the passive response, salinity variability may also play an active role in <span class="hlt">ENSO</span> evolution, and thus important in forecasting El Niño events. By comparing two forecast experiments in which the interannually variability of salinity in the ocean initial states is either included or excluded, the salinity variability is shown to be essential to correctly forecast the 2007/08 La Niña starting from April 2007. With realistic salinity initial states, the tendency to decay of the subsurface cold condition during the spring and early summer 2007 was interrupted by positive salinity anomalies in the upper central Pacific, which working together with the Bjerknes positive feedback, contributed to the development of the La Niña event. Our study suggests that <span class="hlt">ENSO</span> forecasts will benefit from more accurate salinity observations with large-scale spatial coverage. PMID:25352285</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25352285','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25352285"><span>Salinity anomaly as a trigger for <span class="hlt">ENSO</span> events.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Jieshun; Huang, Bohua; Zhang, Rong-Hua; Hu, Zeng-Zhen; Kumar, Arun; Balmaseda, Magdalena A; Marx, Lawrence; Kinter, James L</p> <p>2014-10-29</p> <p>According to the classical theories of <span class="hlt">ENSO</span>, subsurface anomalies in ocean thermal structure are precursors for <span class="hlt">ENSO</span> events and their initial specification is essential for skillful <span class="hlt">ENSO</span> forecast. Although ocean salinity in the tropical Pacific (particularly in the western Pacific warm pool) can vary in response to El Niño events, its effect on <span class="hlt">ENSO</span> evolution and forecasts of <span class="hlt">ENSO</span> has been less explored. Here we present evidence that, in addition to the passive response, salinity variability may also play an active role in <span class="hlt">ENSO</span> evolution, and thus important in forecasting El Niño events. By comparing two forecast experiments in which the interannually variability of salinity in the ocean initial states is either included or excluded, the salinity variability is shown to be essential to correctly forecast the 2007/08 La Niña starting from April 2007. With realistic salinity initial states, the tendency to decay of the subsurface cold condition during the spring and early summer 2007 was interrupted by positive salinity anomalies in the upper central Pacific, which working together with the Bjerknes positive feedback, contributed to the development of the La Niña event. Our study suggests that <span class="hlt">ENSO</span> forecasts will benefit from more accurate salinity observations with large-scale spatial coverage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4248788','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4248788"><span>Spectroscopic AC Susceptibility Imaging (s<span class="hlt">ASI</span>) of Magnetic Nanoparticles</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ficko, Bradley W.; Nadar, Priyanka M.; Diamond, Solomon G.</p> <p>2014-01-01</p> <p>This study demonstrates a method for alternating current (AC) susceptibility imaging (<span class="hlt">ASI</span>) of magnetic nanoparticles (mNPs) using low cost instrumentation. The <span class="hlt">ASI</span> method uses AC magnetic susceptibility measurement to create tomographic images using an array of drive coils, compensation coils and fluxgate magnetometers. Using a spectroscopic approach in conjunction with <span class="hlt">ASI</span>, a series of tomographic images can be created for each frequency measurement and is termed s<span class="hlt">ASI</span>. The advantage of s<span class="hlt">ASI</span> is that mNPs can be simultaneously characterized and imaged in a biological medium. System calibration was performed by fitting the in-phase and out-of-phase susceptibility measurements of an mNP sample with a hydrodynamic diameter of 100 nm to a Brownian relaxation model (R2 = 0.96). Samples of mNPs with core diameters of 10 and 40 nm and a sample of 100 nm hydrodynamic diameter were prepared in 0.5 ml tubes. Three mNP samples were arranged in a randomized array and then scanned using s<span class="hlt">ASI</span> with six frequencies between 425 and 925 Hz. The s<span class="hlt">ASI</span> scans showed the location and quantity of the mNP samples (R2 = 0.97). Biological compatibility of the s<span class="hlt">ASI</span> method was demonstrated by scanning mNPs that were injected into a pork sausage. The mNP response in the biological medium was found to correlate with a calibration sample (R2 = 0.97, p <0.001). These results demonstrate the concept of <span class="hlt">ASI</span> and advantages of s<span class="hlt">ASI</span>. PMID:25477704</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatSR...742281Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatSR...742281Z"><span><span class="hlt">ENSO</span> elicits opposing responses of semi-arid vegetation between Hemispheres</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Anzhi; Jia, Gensuo; Epstein, Howard E.; Xia, Jiangjiang</p> <p>2017-02-01</p> <p>Semi-arid ecosystems are key contributors to the global carbon cycle and may even dominate the inter-annual variability (IAV) and trends of the land carbon sink, driven largely by the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). The linkages between dynamics of semi-arid ecosystems and climate at the hemispheric scale however are not well known. Here, we use satellite data and climate observations from 2000 to 2014 to explore the impacts of <span class="hlt">ENSO</span> on variability of semi-arid ecosystems, using the Ensemble Empirical Mode Decomposition method. We show that the responses of semi-arid vegetation to <span class="hlt">ENSO</span> occur in opposite directions, resulting from opposing controls of <span class="hlt">ENSO</span> on precipitation between the Northern Hemisphere (positively correlated to <span class="hlt">ENSO</span>) and the Southern Hemisphere (negatively correlated to <span class="hlt">ENSO</span>). Also, the Southern Hemisphere, with a robust negative coupling of temperature and precipitation anomalies, exhibits stronger and faster responses of semi-arid ecosystems to <span class="hlt">ENSO</span> than the Northern Hemisphere. Our findings suggest that natural coherent variability in semi-arid ecosystem productivity responded to <span class="hlt">ENSO</span> in opposite ways between two hemispheres, which may imply potential prediction of global semi-arid ecosystem variability, particularly based on variability in tropical Pacific Sea Surface Temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=269692','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=269692"><span>Effect of <span class="hlt">ENSO</span> on Corn Aflatoxin in South Georgia</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is associated with climate variability around the world, and is known to adversely affect food production systems. In the Southeastern US, research has shown that <span class="hlt">ENSO</span> influences crop production. Two multivariate <span class="hlt">ENSO</span> Indices, MEI and Niño 3.4, are typical...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP31A1271W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP31A1271W"><span>Last Millennium <span class="hlt">ENSO</span>-Mean State Interactions in the Tropical Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wyman, D. A.; Conroy, J. L.; Karamperidou, C.</p> <p>2017-12-01</p> <p>The nature and degree of interaction between the mean state of the tropical Pacific and <span class="hlt">ENSO</span> remains an open question. Here we use high temporal resolution, tropical Pacific sea surface temperature (SST) records from the last millennium to investigate the relationship between <span class="hlt">ENSO</span> and the tropical Pacific zonal sea surface temperature gradient (hereafter dSST). A dSST time series was created by standardizing, interpolating, and compositing 7 SST records from the western and 3 SST records from the eastern tropical Pacific. Propagating the age uncertainty of each of these records was accomplished through a Monte Carlo Empirical Orthogonal Function analysis. We find last millennium dSST is strong from 700 to 1300 CE, begins to weaken at approximately 1300 CE, and decreases more rapidly at 1700 CE. dSST was compared to 14 different <span class="hlt">ENSO</span> reconstructions, independent of the records used to create dSST, to assess the nature of the <span class="hlt">ENSO</span>-mean state relationship. dSST correlations with 50-year standard deviations of <span class="hlt">ENSO</span> reconstructions are consistently negative, suggesting that more frequent, strong El Niño events on this timescale reduces dSST. To further assess the strength and direction of the <span class="hlt">ENSO</span>-dSST relationship, moving 100-year standard deviations of <span class="hlt">ENSO</span> reconstructions were compared to moving 100-year averages of dSST using Cohen's Kappa statistic, which measures categorical agreement. The Li et al. (2011) and Li et al. (2013) Nino 3.4 <span class="hlt">ENSO</span> reconstructions had the highest agreement with dSST (k=0.80 and 0.70, respectively), with greater <span class="hlt">ENSO</span> standard deviation coincident with periods of weak dSST. Other <span class="hlt">ENSO</span> reconstructions showed weaker agreement with dSST, which may be partly due to low sample size. The consistent directional agreement of dSST with <span class="hlt">ENSO</span>, coupled with the inability of strong <span class="hlt">ENSO</span> events to develop under a weak SST gradient, suggests periods of more frequent strong El Niño events reduced tropical Pacific dSST on centennial timescales over the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1801g0001H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1801g0001H"><span>Seasonal <span class="hlt">ENSO</span> forecasting: Where does a simple model stand amongst other operational <span class="hlt">ENSO</span> models?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Halide, Halmar</p> <p>2017-01-01</p> <p>We apply a simple linear multiple regression model called IndOzy for predicting <span class="hlt">ENSO</span> up to 7 seasonal lead times. The model still used 5 (five) predictors of the past seasonal Niño 3.4 <span class="hlt">ENSO</span> indices derived from chaos theory and it was rolling-validated to give a one-step ahead forecast. The model skill was evaluated against data from the season of May-June-July (MJJ) 2003 to November-December-January (NDJ) 2015/2016. There were three skill measures such as: Pearson correlation, RMSE, and Euclidean distance were used for forecast verification. The skill of this simple model was than compared to those of combined Statistical and Dynamical models compiled at the IRI (International Research Institute) website. It was found that the simple model was only capable of producing a useful <span class="hlt">ENSO</span> prediction only up to 3 seasonal leads, while the IRI statistical and Dynamical model skill were still useful up to 4 and 6 seasonal leads, respectively. Even with its short-range seasonal prediction skills, however, the simple model still has a potential to give <span class="hlt">ENSO</span>-derived tailored products such as probabilistic measures of precipitation and air temperature. Both meteorological conditions affect the presence of wild-land fire hot-spots in Sumatera and Kalimantan. It is suggested that to improve its long-range skill, the simple INDOZY model needs to incorporate a nonlinear model such as an artificial neural network technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JMetR..31...73H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JMetR..31...73H"><span>Interdecadal variations of <span class="hlt">ENSO</span> around 1999/2000</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Zeng-Zhen; Kumar, Arun; Huang, Bohua; Zhu, Jieshun; Ren, Hong-Li</p> <p>2017-02-01</p> <p>This paper discusses the interdecadal changes of the climate in the tropical Pacific with a focus on the corresponding changes in the characteristics of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Compared with 1979-1999, the whole tropical Pacific climate system, including both the ocean and atmosphere, shifted to a lower variability regime after 1999/2000. Meanwhile, the frequency of <span class="hlt">ENSO</span> became less regular and was closer to a white noise process. The lead time of the equatorial Pacific's subsurface ocean heat content in preceding <span class="hlt">ENSO</span> decreased remarkably, in addition to a reduction in the maximum correlation between them. The weakening of the correlation and the shortening of the lead time pose more challenges for <span class="hlt">ENSO</span> prediction, and is the likely reason behind the decrease in skill with respect to <span class="hlt">ENSO</span> prediction after 2000. Coincident with the changes in tropical Pacific climate variability, the mean states of the atmospheric and oceanic components also experienced physically coherent changes. The warm anomaly of SST in the western Pacific and cold anomaly in the eastern Pacific resulted in an increased zonal SST gradient, linked to an enhancement in surface wind stress and strengthening of the Walker circulation, as well as an increase in the slope of the thermocline. These changes were consistent with an increase (a decrease) in precipitation and an enhancement (a suppression) of the deep convection in the western (eastern) equatorial Pacific. Possible connections between the mean state and <span class="hlt">ENSO</span> variability and frequency changes in the tropical Pacific are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/enso_cycle.shtml','SCIGOVWS'); return false;" href="http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/enso_cycle.shtml"><span>Climate Prediction Center - The <span class="hlt">ENSO</span> Cycle</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Weather Service NWS logo - Click to go to the NWS home page <em>Climate</em> Prediction Center Home Site Map News Web resources and services. HOME > El Niño/La Niña > The <span class="hlt">ENSO</span> Cycle <span class="hlt">ENSO</span> Cycle Banner <em>Climate</em> for Weather and <em>Climate</em> Prediction <em>Climate</em> Prediction Center 5830 University Research Court College</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp...74Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp...74Z"><span>Impact of <span class="hlt">ENSO</span> longitudinal position on teleconnections to the NAO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wenjun; Wang, Ziqi; Stuecker, Malte F.; Turner, Andrew G.; Jin, Fei-Fei; Geng, Xin</p> <p>2018-02-01</p> <p>While significant improvements have been made in understanding how the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) impacts both North American and Asian climate, its relationship with the North Atlantic Oscillation (NAO) remains less clear. Observations indicate that <span class="hlt">ENSO</span> exhibits a highly complex relationship with the NAO-associated atmospheric circulation. One critical contribution to this ambiguous <span class="hlt">ENSO</span>/NAO relationship originates from <span class="hlt">ENSO</span>'s diversity in its spatial structure. In general, both eastern (EP) and central Pacific (CP) El Niño events tend to be accompanied by a negative NAO-like atmospheric response. However, for two different types of La Niña the NAO response is almost opposite. Thus, the NAO responses for the CP <span class="hlt">ENSO</span> are mostly linear, while nonlinear NAO responses dominate for the EP <span class="hlt">ENSO</span>. These contrasting extra-tropical atmospheric responses are mainly attributed to nonlinear air-sea interactions in the tropical eastern Pacific. The local atmospheric response to the CP <span class="hlt">ENSO</span> sea surface temperature (SST) anomalies is highly linear since the air-sea action center is located within the Pacific warm pool, characterized by relatively high climatological SSTs. In contrast, the EP <span class="hlt">ENSO</span> SST anomalies are located in an area of relatively low climatological SSTs in the eastern equatorial Pacific. Here only sufficiently high positive SST anomalies during EP El Niño events are able to overcome the SST threshold for deep convection, while hardly any anomalous convection is associated with EP La Niña SSTs that are below this threshold. This <span class="hlt">ENSO</span>/NAO relationship has important implications for NAO seasonal prediction and places a higher requirement on models in reproducing the full diversity of <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A42E..08P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A42E..08P"><span>Future Changes to <span class="hlt">ENSO</span> Temperature and Precipitation Teleconnections Under Warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perry, S.; McGregor, S.; Sen Gupta, A.; England, M. H.</p> <p>2016-12-01</p> <p>As the dominant mode of interannual climate variability, the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) modulates temperature and rainfall globally, additionally contributing to weather extremes. Anthropogenic climate change has the potential to alter the strength and frequency of <span class="hlt">ENSO</span> and may also alter <span class="hlt">ENSO</span>-driven atmospheric teleconnections, affecting ecosystems and human activity in regions far removed from the tropical Pacific. State-of-art climate models exhibit considerable disagreement in projections of future changes in <span class="hlt">ENSO</span> sea surface temperature variability. Despite this uncertainty, recent model studies suggest that the precipitation response to <span class="hlt">ENSO</span> will be enhanced in the tropical Pacific under future warming, and as such the societal impacts of <span class="hlt">ENSO</span> will increase. Here we use temperature and precipitation data from an ensemble of 41 CMIP5 models to show where <span class="hlt">ENSO</span> teleconnections are being enhanced and dampened in a high-emission future scenario (RCP8.5) focusing on the changes that are occurring over land areas globally. Although there is some spread between the model projections, robust changes with strong ensemble agreement are found in certain locations, including amplification of teleconnections in southeast Australia, South America and the Maritime Continent. Our results suggest that in these regions future <span class="hlt">ENSO</span> events will lead to more extreme temperature and rainfall responses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B33C2098X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B33C2098X"><span>Effects of <span class="hlt">ENSO</span>-induced extremes on terrestrial ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, M.; Hoffman, F. M.</p> <p>2017-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) with its warm (El Niño) and cold phase (La Niña) has well-known global impacts on the Earth system through the mechanism of teleconnections. Not only the global mean temperature and precipitation distributions will be changed but also the climate extremes will be enhanced during <span class="hlt">ENSO</span> events. In this study, the advanced Earth System Model ACME version 0.3 was used to simulate terrestrial biogeochemistry and global climate from 1982 to 2020 with prescribed Sea Surface Temperature (SST) from data fusions of the NOAA high resolution daily Optimum Interpolation SST (OISST), CFS v2 9-month seasonal forecast and data reconstructions. We investigated how <span class="hlt">ENSO</span>-induced climate extremes affect land carbon dynamics both regionally and globally and the implications for the functioning of different vegetated ecosystems under the influence of climate extremes. The results show that the <span class="hlt">ENSO</span>-induced climate extremes, especially drought and heat waves, have significant impacts on the terrestrial carbon cycle. The responses to <span class="hlt">ENSO</span>-induced climate extremes are divergent among different vegetation types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41B1010S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41B1010S"><span>Change of <span class="hlt">ENSO</span> characteristics in response to global warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, X.; Xia, Y.; Yan, Y.; Feng, W.; Huang, F.; Yang, X. Q.</p> <p>2017-12-01</p> <p>By using datasets of HadISST monthly SST from 1895 to 2014 and 600-year simulations of two CESM model experiments with/without doubling of CO2 concentration, <span class="hlt">ENSO</span> characteristics are compared pre- and post- global warming. The main results are as follows. Due to global warming, the maximum climatological SST warming occurs in the tropical western Pacific (La Niña-like background warming) and the tropical eastern Pacific (El Niño-like background warming) for observations and model, respectively, resulting in opposite zonal SST gradient anomalies in the tropical Pacific. The La Niña-like background warming induces intense surface divergence in the tropical central Pacific, which enhances the easterly trade winds in the tropical central-western Pacific and shifts the strongest ocean-atmosphere coupling westward, correspondingly. On the contrary, the El Niño-like background warming causes westerly winds in the whole tropical Pacific and moves the strongest ocean-atmosphere coupling eastward. Under the La Niña-like background warming, <span class="hlt">ENSO</span> tends to develop and mature in the tropical central Pacific, because the background easterly wind anomaly weakens the <span class="hlt">ENSO</span>-induced westerly wind anomaly in the tropical western Pacific, leading to the so-called "Central Pacific <span class="hlt">ENSO</span> (CP <span class="hlt">ENSO</span>)". However, the so-called "Eastern Pacific <span class="hlt">ENSO</span> (EP <span class="hlt">ENSO</span>)" is likely formed due to increased westerly wind anomaly by the El Niño-like background warming. <span class="hlt">ENSO</span> lifetime is significantly extended under both the El Niño-like and the La Niña-like background warmings, and especially, it can be prolonged by up to 3 months in the situation of El Niño-like background warming. The prolonged El Nino lifetime mainly applies to extreme El Niño events, which is caused by earlier outbreak of the westerly wind bursts, shallower climatological thermocline depth and weaker "discharge" rate of the <span class="hlt">ENSO</span> warm signal in response to global warming. Results from both observations and the model also show that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018RvGeo..56..185Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018RvGeo..56..185Y"><span><span class="hlt">ENSO</span> Atmospheric Teleconnections and Their Response to Greenhouse Gas Forcing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeh, Sang-Wook; Cai, Wenju; Min, Seung-Ki; McPhaden, Michael J.; Dommenget, Dietmar; Dewitte, Boris; Collins, Matthew; Ashok, Karumuri; An, Soon-Il; Yim, Bo-Young; Kug, Jong-Seong</p> <p>2018-03-01</p> <p>El Niño and Southern Oscillation (<span class="hlt">ENSO</span>) is the most prominent year-to-year climate fluctuation on Earth, alternating between anomalously warm (El Niño) and cold (La Niña) sea surface temperature (SST) conditions in the tropical Pacific. <span class="hlt">ENSO</span> exerts its impacts on remote regions of the globe through atmospheric teleconnections, affecting extreme weather events worldwide. However, these teleconnections are inherently nonlinear and sensitive to <span class="hlt">ENSO</span> SST anomaly patterns and amplitudes. In addition, teleconnections are modulated by variability in the oceanic and atmopsheric mean state outside the tropics and by land and sea ice extent. The character of <span class="hlt">ENSO</span> as well as the ocean mean state have changed since the 1990s, which might be due to either natural variability or anthropogenic forcing, or their combined influences. This has resulted in changes in <span class="hlt">ENSO</span> atmospheric teleconnections in terms of precipitation and temperature in various parts of the globe. In addition, changes in <span class="hlt">ENSO</span> teleconnection patterns have affected their predictability and the statistics of extreme events. However, the short observational record does not allow us to clearly distinguish which changes are robust and which are not. Climate models suggest that <span class="hlt">ENSO</span> teleconnections will change because the mean atmospheric circulation will change due to anthropogenic forcing in the 21st century, which is independent of whether <span class="hlt">ENSO</span> properties change or not. However, future <span class="hlt">ENSO</span> teleconnection changes do not currently show strong intermodel agreement from region to region, highlighting the importance of identifying factors that affect uncertainty in future model projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMGC22A..05C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMGC22A..05C"><span>Future Projections of <span class="hlt">ENSO</span> and Drought (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cane, M. A.</p> <p>2009-12-01</p> <p>Jule Charney, who was my advisor, worked very broadly - and profoundly - on climate dynamics. In this discussion of the present state of knowledge I will focus on two aspects of climate that I view as legacies of his work: our ability to project climate variability in the tropics and to project drought. (I have in mind his work with Shukla on predictability of monsoons, and Charney 1975, Dynamics of deserts and drought in the Sahel., Q. J. Roy. Meteor. Soc., 101, 193-202). First, I will consider the projections of <span class="hlt">ENSO</span> (El Niño and Southern Oscillation) in a warming world. (My own interest in <span class="hlt">ENSO</span> was piqued in discussions with Charney and others during the <span class="hlt">ENSO</span>-influenced blocking events in the late 1970s; in good measure, the approach I took to understanding and modeling <span class="hlt">ENSO</span> was based in my thesis work.) Current IPCC models differ markedly in their projections of the mean state of the equatorial Pacific, some favoring a more “El Niño- like”, some the opposite. Possible reasons for these disagreements will be considered in the light of our understanding of <span class="hlt">ENSO</span> and tropical climate more generally. Observational data for the past century and a half will figure prominently. Droughts in the US Southwest have a strong <span class="hlt">ENSO</span> signal, but IPCC models are fairly consistent in projecting enhanced drought there. The reasons for this will be discussed. Models are less consistent in their predictions of the future Sahel. I will discuss what is understood about causes of drought in the Sahel, which appear to point toward sea surface temperature as the controlling influence, in contrast to Charney’s albedo hypothesis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ThApC.122..271M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ThApC.122..271M"><span>Relationships between Rwandan seasonal rainfall anomalies and <span class="hlt">ENSO</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muhire, I.; Ahmed, F.; Abutaleb, K.</p> <p>2015-10-01</p> <p>This study aims primarily at investigating the relationships between Rwandan seasonal rainfall anomalies and El Niño-South Oscillation phenomenon (<span class="hlt">ENSO</span>) events. The study is useful for early warning of negative effects associated with extreme rainfall anomalies across the country. It covers the period 1935-1992, using long and short rains data from 28 weather stations in Rwanda and <span class="hlt">ENSO</span> events resourced from Glantz (2001). The mean standardized anomaly indices were calculated to investigate their associations with <span class="hlt">ENSO</span> events. One-way analysis of variance was applied on the mean standardized anomaly index values per <span class="hlt">ENSO</span> event to explore the spatial correlation of rainfall anomalies per <span class="hlt">ENSO</span> event. A geographical information system was used to present spatially the variations in mean standardized anomaly indices per <span class="hlt">ENSO</span> event. The results showed approximately three climatic periods, namely, dry period (1935-1960), semi-humid period (1961-1976) and wet period (1977-1992). Though positive and negative correlations were detected between extreme short rains anomalies and El Niño events, La Niña events were mostly linked to negative rainfall anomalies while El Niño events were associated with positive rainfall anomalies. The occurrence of El Niño and La Niña in the same year does not show any clear association with rainfall anomalies. However, the phenomenon was more linked with positive long rains anomalies and negative short rains anomalies. The normal years were largely linked with negative long rains anomalies and positive short rains anomalies, which is a pointer to the influence of other factors other than <span class="hlt">ENSO</span> events. This makes projection of seasonal rainfall anomalies in the country by merely predicting <span class="hlt">ENSO</span> events difficult.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1425660-enso-driven-energy-budget-perturbations-observations-cmip-models','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1425660-enso-driven-energy-budget-perturbations-observations-cmip-models"><span><span class="hlt">ENSO</span>-driven energy budget perturbations in observations and CMIP models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Mayer, Michael; Fasullo, John T.; Trenberth, Kevin E.; ...</p> <p>2016-03-19</p> <p>Various observation-based datasets are employed to robustly quantify changes in ocean heat content (OHC), anomalous ocean–atmosphere energy exchanges and atmospheric energy transports during El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). These results are used as a benchmark to evaluate the energy pathways during <span class="hlt">ENSO</span> as simulated by coupled climate model runs from the CMIP3 and CMIP5 archives. The models are able to qualitatively reproduce observed patterns of <span class="hlt">ENSO</span>-related energy budget variability to some degree, but key aspects are seriously biased. Area-averaged tropical Pacific OHC variability associated with <span class="hlt">ENSO</span> is greatly underestimated by all models because of strongly biased responses of net radiation atmore » top-of-the-atmosphere to <span class="hlt">ENSO</span>. The latter are related to biases of mean convective activity in the models and project on surface energy fluxes in the eastern Pacific Intertropical Convergence Zone region. Moreover, models underestimate horizontal and vertical OHC redistribution in association with the generally too weak Bjerknes feedback, leading to a modeled <span class="hlt">ENSO</span> affecting a too shallow layer of the Pacific. Vertical links between SST and OHC variability are too weak even in models driven with observed winds, indicating shortcomings of the ocean models. Furthermore, modeled teleconnections as measured by tropical Atlantic OHC variability are too weak and the tropical zonal mean <span class="hlt">ENSO</span> signal is strongly underestimated or even completely missing in most of the considered models. In conclusion, results suggest that attempts to infer insight about climate sensitivity from <span class="hlt">ENSO</span>-related variability are likely to be hampered by biases in <span class="hlt">ENSO</span> in CMIP simulations that do not bear a clear link to future changes.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC42A..09B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC42A..09B"><span>Intensified <span class="hlt">ENSO</span>-Driven Precipitation Teleconnections in the Future</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonfils, C.; Santer, B. D.; Phillips, T. J.; Marvel, K.; Leung, L. R.; Doutriaux, C.</p> <p>2014-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is an important driver of regional hydroclimate variability through far-reaching teleconnections. Most climate models project an increase in the frequency of extreme El Niño events under increased greenhouse-gas (GHG) forcing. However, it is unclear how other aspects of <span class="hlt">ENSO</span> and <span class="hlt">ENSO</span>-driven teleconnections will evolve in the future. Here, we identify in 20th century sea-surface temperature (SST) observations a time-invariant <span class="hlt">ENSO</span>-like (ENSOL) pattern that is largely uncontaminated by GHG forcing. We use this pattern to investigate the future precipitation (P) response to <span class="hlt">ENSO</span>-like SST anomalies. Models that better capture observed ENSOL characteristics produce P teleconnection patterns that are in better accord with observations and more stationary in the 21st century. We decompose the future P response to ENSOL into the sum of three terms: (1) the change in P mean state, (2) the historical P response to ENSOL, and (3) a future enhancement in the P response to ENSOL. In many regions, this last term can aggravate the P extremes associated with <span class="hlt">ENSO</span> variability. This simple decomposition allows us to identify regions likely to experience ENSOL-induced P changes that are without precedent in the current climate. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.4272A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.4272A"><span>Feedback process responsible for intermodel diversity of <span class="hlt">ENSO</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>An, Soon-Il; Heo, Eun Sook; Kim, Seon Tae</p> <p>2017-05-01</p> <p>The origin of the intermodel diversity of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) variability is investigated by applying a singular value decomposition (SVD) analysis between the intermodel tropical Pacific sea surface temperature anomalies (SSTA) variance and the intermodel <span class="hlt">ENSO</span> stability index (BJ index). The first SVD mode features an <span class="hlt">ENSO</span>-like pattern for the intermodel SSTA variance (74% of total variance) and the dominant thermocline feedback (TH) for the BJ index (51%). Intermodel TH is mainly modified by the intermodel sensitivity of the zonal thermocline gradient response to zonal winds over the equatorial Pacific (βh), and the intermodel βh is correlated higher with the intermodel off-equatorial wind stress curl anomalies than the equatorial zonal wind stress anomalies. Finally, the intermodel off-equatorial wind stress curl is associated with the meridional shape and intensity of <span class="hlt">ENSO</span>-related wind patterns, which may cause a model-to-model difference in <span class="hlt">ENSO</span> variability by influencing the off-equatorial oceanic Rossby wave response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NPGeo..18...29H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NPGeo..18...29H"><span>Interactions between marine biota and <span class="hlt">ENSO</span>: a conceptual model analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heinemann, M.; Timmermann, A.; Feudel, U.</p> <p>2011-01-01</p> <p>We develop a conceptual coupled atmosphere-ocean-ecosystem model for the tropical Pacific to investigate the interaction between marine biota and the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Ocean and atmosphere are represented by a two-box model for the equatorial Pacific cold tongue and the warm pool, including a simplified mixed layer scheme. Marine biota are represented by a three-component (nutrient, phytoplankton, and zooplankton) ecosystem model. The atmosphere-ocean model exhibits an oscillatory state which qualitatively captures the main physics of <span class="hlt">ENSO</span>. During an <span class="hlt">ENSO</span> cycle, the variation of nutrient upwelling, and, to a small extent, the variation of photosynthetically available radiation force an ecosystem oscillation. The simplified ecosystem in turn, due to the effect of phytoplankton on the absorption of shortwave radiation in the water column, leads to (1) a warming of the tropical Pacific, (2) a reduction of the <span class="hlt">ENSO</span> amplitude, and (3) a prolongation of the <span class="hlt">ENSO</span> period. We qualitatively investigate these bio-physical coupling mechanisms using continuation methods. It is demonstrated that bio-physical coupling may play a considerable role in modulating <span class="hlt">ENSO</span> variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmEn.167..426W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmEn.167..426W"><span><span class="hlt">ENSO</span>-related PM10 variability on the Korean Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wie, Jieun; Moon, Byung-Kwon</p> <p>2017-10-01</p> <p>Particulate matter, defined as particles of less than 10 μm in diameter (PM10), was analyzed over the Korean Peninsula from 2001 to 2015 to examine the influence of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on subseasonal PM10 variability. The PM10 data were obtained from 151 air quality monitoring stations provided by the Korea Environment Corporation (KECO). Lead-lag correlation analysis, which was performed to investigate the connection between NDJF (November-February) NINO3 index and seasonal mean PM10 data, did not yield any statistically significant correlations. However, using five-pentad moving-averaged PM10 data, statistically significant correlations between NDJF NINO3 index and PM10 variability were found in four subseasonal periods, with alternating positive and negative correlations. In the periods during which PM10 levels on the Korean Peninsula were positively (negatively) correlated with the <span class="hlt">ENSO</span> index, the positive PM10 anomalies are associated with El Niño (La Niña) years, which implies that the occurrence of high-PM10 events could be modulated by the <span class="hlt">ENSO</span> phase. In addition, this <span class="hlt">ENSO</span>-related PM10 variation is negatively correlated with <span class="hlt">ENSO</span>-related precipitation in the Korean Peninsula, indicating that more (less) wet deposition leads to lower (higher) PM10 level. Therefore, we conclude that the <span class="hlt">ENSO</span>-induced precipitation anomalies over the Korean Peninsula are mainly responsible for <span class="hlt">ENSO</span>-related PM10 variations. This study will be helpful for further identifying detailed chemistry-climate processes that control PM10 concentrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70016220','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70016220"><span>Expression of seasonal and <span class="hlt">ENSO</span> forcing in climatic variability at lower than <span class="hlt">ENSO</span> frequencies: evidence from Pleistocene marine varves off California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anderson, R.Y.; Linsley, B.K.; Gardner, J.V.</p> <p>1990-01-01</p> <p>Upper Pleistocene marine sediments along the upper continental slope off northern and central California contain alternations of varved and bioturbated sediments and associated changes in biota and sediment composition. These alternations can be related to conditions that accompany El Nin??o and anti-El Nin??o (<span class="hlt">ENSO</span>) circulation. Anti-El Nin??o conditions are characterized by increased upwelling and productivity and by low concentrations of dissolved oxygen in the oxygen minimum zone that resulted in varve preservation. El Nin??o conditions are characterized by little or no upwelling, low productivity, and higher concentrations of dissolved oxygen that resulted in zones of bioturbation. Alternations of varves and zones of bioturbation, that range from decades to millennia, occur through the upper Pleistocene section. The inferred long-term alternations in El Nin??o and anti-El Nin??o conditions appear to be a re-expression of <span class="hlt">ENSO</span>'s primary 3-7 year cycle. Decadal to millennial cycles of productivity associated with El Nin??o and anti-El Nin??o conditions may have served as a "carbon pump" and transferred atmospheric CO2 to the marine reservoir. Changes in sediment composition and organisms associated with El Nin??o or anti-El Nin??o conditions can be related to both seasonal and <span class="hlt">ENSO</span> phenomena. Expression of these changes at lower-than-<span class="hlt">ENSO</span> frequencies may be partly explained by adding the effects of seasonal variability to effects produced by a self-oscillating <span class="hlt">ENSO</span> system. However, deterministic mechanisms, including solar modulation of <span class="hlt">ENSO</span>, may also contribute to long-term alternations of El Nin??o and anti-El Nin??o conditions. ?? 1990.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..4312560Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..4312560Z"><span>Modulation of Bjerknes feedback on the decadal variations in <span class="hlt">ENSO</span> predictability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Fei; Fang, Xiang-Hui; Zhu, Jiang; Yu, Jin-Yi; Li, Xi-Chen</p> <p>2016-12-01</p> <p>Clear decadal variations exist in the predictability of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), with the most recent decade having the lowest <span class="hlt">ENSO</span> predictability in the past six decades. The Bjerknes Feedback (BF) intensity, which dominates the development of <span class="hlt">ENSO</span>, has been proposed to determine <span class="hlt">ENSO</span> predictability. Here we demonstrate that decadal variations in BF intensity are largely a result of the sensitivity of the zonal winds to the zonal sea level pressure (SLP) gradient in the equatorial Pacific. Furthermore, the results show that during low-<span class="hlt">ENSO</span> predictability decades, zonal wind anomalies over the equatorial Pacific are more linked to SLP variations in the off-equatorial Pacific, which can then transfer this information into surface temperature and precipitation fields through the BF, suggesting a weakening in the ocean-atmosphere coupling in the tropical Pacific. This result indicates that more attention should be paid to off-equatorial processes in the prediction of <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28685758','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28685758"><span>Greening of the Sahara suppressed <span class="hlt">ENSO</span> activity during the mid-Holocene.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pausata, Francesco S R; Zhang, Qiong; Muschitiello, Francesco; Lu, Zhengyao; Chafik, Léon; Niedermeyer, Eva M; Stager, J Curt; Cobb, Kim M; Liu, Zhengyu</p> <p>2017-07-07</p> <p>The evolution of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) during the Holocene remains uncertain. In particular, a host of new paleoclimate records suggest that <span class="hlt">ENSO</span> internal variability or other external forcings may have dwarfed the fairly modest <span class="hlt">ENSO</span> response to precessional insolation changes simulated in climate models. Here, using fully coupled ocean-atmosphere model simulations, we show that accounting for a vegetated and less dusty Sahara during the mid-Holocene relative to preindustrial climate can reduce <span class="hlt">ENSO</span> variability by 25%, more than twice the decrease obtained using orbital forcing alone. We identify changes in tropical Atlantic mean state and variability caused by the momentous strengthening of the West Africa Monsoon (WAM) as critical factors in amplifying <span class="hlt">ENSO</span>'s response to insolation forcing through changes in the Walker circulation. Our results thus suggest that potential changes in the WAM due to anthropogenic warming may influence <span class="hlt">ENSO</span> variability in the future as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2361H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2361H"><span>Contribution of tropical instability waves to <span class="hlt">ENSO</span> irregularity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holmes, Ryan M.; McGregor, Shayne; Santoso, Agus; England, Matthew H.</p> <p>2018-05-01</p> <p>Tropical instability waves (TIWs) are a major source of internally-generated oceanic variability in the equatorial Pacific Ocean. These non-linear phenomena play an important role in the sea surface temperature (SST) budget in a region critical for low-frequency modes of variability such as the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). However, the direct contribution of TIW-driven stochastic variability to <span class="hlt">ENSO</span> has received little attention. Here, we investigate the influence of TIWs on <span class="hlt">ENSO</span> using a 1/4° ocean model coupled to a simple atmosphere. The use of a simple atmosphere removes complex intrinsic atmospheric variability while allowing the dominant mode of air-sea coupling to be represented as a statistical relationship between SST and wind stress anomalies. Using this hybrid coupled model, we perform a suite of coupled ensemble forecast experiments initiated with wind bursts in the western Pacific, where individual ensemble members differ only due to internal oceanic variability. We find that TIWs can induce a spread in the forecast amplitude of the Niño 3 SST anomaly 6-months after a given sequence of WWBs of approximately ± 45% the size of the ensemble mean anomaly. Further, when various estimates of stochastic atmospheric forcing are added, oceanic internal variability is found to contribute between about 20% and 70% of the ensemble forecast spread, with the remainder attributable to the atmospheric variability. While the oceanic contribution to <span class="hlt">ENSO</span> stochastic forcing requires further quantification beyond the idealized approach used here, our results nevertheless suggest that TIWs may impact <span class="hlt">ENSO</span> irregularity and predictability. This has implications for <span class="hlt">ENSO</span> representation in low-resolution coupled models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070031877','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070031877"><span>The <span class="hlt">ENSO</span> Effect on the Temporal and Spatial Distribution of Global Lightning Activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chronis, Themis G.; Goodman, Steven J.; Cecil, Dan; Buechler, Dennis; Pittman, Jasna; Robertson, Franklin R.; Blakeslee, Richard J.</p> <p>2007-01-01</p> <p>The recently reprocessed (1997-2006) OTD/LIS database is used to investigate the global lightning climatology in response to the <span class="hlt">ENSO</span> cycle. A linear correlation map between lightning anomalies and <span class="hlt">ENSO</span> (NINO3.4) identifies areas that generally follow patterns similar to precipitation anomalies. We also observed areas where significant lightning/<span class="hlt">ENSO</span> correlations are found and are not accompanied of significant precipitation/<span class="hlt">ENSO</span> correlations. An extreme case of the strong decoupling between lightning and precipitation is observed over the Indonesian peninsula (Sumatra) where positive lightning/NINO3.4 correlations are collocated with negative precipitation/NINO3.4 correlations. Evidence of linear relationships between the spatial extent of thunderstorm distribution and the respective NINO3.4 magnitude are presented for different regions on the Earth. Strong coupling is found over areas remote to the main <span class="hlt">ENSO</span> axis of influence and both during warm and cold <span class="hlt">ENSO</span> phases. Most of the resulted relationships agree with the tendencies of precipitation related to <span class="hlt">ENSO</span> empirical maps or documented teleconnection patterns. Over the Australian continent, opposite behavior in terms of thunderstorm activity is noted for warm <span class="hlt">ENSO</span> phases with NINO3.4 magnitudes with NINO3.4>+l.08 and 0<NqNO3.4<I.08. Finally, we investigate the spatial distribution of areas that consistently portrayed enhanced lightning activity during the main warm/cold (El Nino/La Nina) <span class="hlt">ENSO</span> episodes of the past decade. The observed patterns show no spatial overlapping and identify areas that in their majority are in agreement with empirical precipitation/<span class="hlt">ENSO</span> maps. The areas that appear during the warm <span class="hlt">ENSO</span> phase are found over regions that have been identified as anomalous Hadley circulation <span class="hlt">ENSO</span>-related patterns. The areas that appear during the cold <span class="hlt">ENSO</span> phase are found predominantly around the west hemisphere equatorial belt and are in their majority identified by anomalous Walker circulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150022193','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150022193"><span>Stability of <span class="hlt">ENSO</span> and Its Tropical Pacific Teleconnections over the Last Millennium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lewis, Sophie; Legrande, A. N.</p> <p>2015-01-01</p> <p>Determining past changes in the amplitude, frequency and teleconnections of the El Nio Southern Oscillation (<span class="hlt">ENSO</span>) is important for understanding its potential sensitivity to future anthropogenic climate change. Palaeo-reconstructions from proxy records provide long-term information of <span class="hlt">ENSO</span> interactions with the background climatic state through time. However, it remains unclear how <span class="hlt">ENSO</span> characteristics have changed through time, and precisely which signals proxies record. Proxy interpretations are underpinned by the assumption of stationarity in relationships between local and remote climates, and often utilise archives from single locations located in the Pacific Ocean to reconstruct <span class="hlt">ENSO</span> histories. Here, we investigate the stationarity of <span class="hlt">ENSO</span> teleconnections using the Last Millennium experiment of CMIP5 (Coupled Model Intercomparison Project phase 5) (Taylor et al., 2012). We show that modelled <span class="hlt">ENSO</span> characteristics vary on decadal- to centennial-scales, resulting from internal variability and external forcings, such as tropical volcanic eruptions. Furthermore, the relationship between <span class="hlt">ENSO</span> conditions and local climates across the Pacific basin varies throughout the Last Millennium. Results show the stability of teleconnections is regionally dependent and proxies may reveal complex changes in teleconnected patterns, rather than large-scale changes in base <span class="hlt">ENSO</span> characteristics. As such, proxy insights into <span class="hlt">ENSO</span> likely require evidence to be synthesised over large spatial areas in order to deconvolve changes occurring in the NINO3.4 region from those pertaining to proxy-relevant local climatic variables. To obtain robust histories of the <span class="hlt">ENSO</span> and its remote impacts, we recommend interpretations of proxy records should be considered in conjunction with palaeo-reconstructions from within the Central Pacific</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=drought&pg=5&id=EJ758494','ERIC'); return false;" href="https://eric.ed.gov/?q=drought&pg=5&id=EJ758494"><span>Fires, Floods, and Hurricanes: Is <span class="hlt">ENSO</span> to Blame?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mjelde, James W.; Litzenberg, Kerry K.; Hoyle, Julie E.; Holochwost, Sharon R.; Funkhouser, Sarah</p> <p>2007-01-01</p> <p>Scientists have associated the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon with extreme climate events such as flooding in California, droughts in Australia, fires in Indonesia, and increased hurricane activity in the Atlantic Ocean. The popular media is constantly attributing individual storms to the <span class="hlt">ENSO</span> phenomenon. The reality is that a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161152&hterms=forest+trees&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dforest%2Btrees','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161152&hterms=forest+trees&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dforest%2Btrees"><span>Forest Understory Fire in the Brazilian Amazon in <span class="hlt">ENSO</span> and Non-<span class="hlt">ENSO</span> Years: Area Burned and Committed Carbon Emissions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alencar, A.; Nepstad, D.; Ver-Diaz, M. Del. C.</p> <p>2004-01-01</p> <p>"Understory fires" that burn the floor of standing forests are one of the most important types of forest impoverishment in the Amazon, especially during the severe droughts of El Nino Southern Oscillation (<span class="hlt">ENSO</span>) episodes. However, we are aware of no estimates of the areal extent of these fires for the Brazilian Amazon and, hence, of their contribution to Amazon carbon fluxes to the atmosphere. We calculated the area of forest understory fires for the Brazilian Amazon region during an El Nino (1998) and a non El Nino (1995) year based on forest fire scars mapped with satellite images for three locations in eastern and southern Amazon, where deforestation is concentrated. The three study sites represented a gradient of both forest types and dry season severity. The burning scar maps were used to determine how the percentage of forest that burned varied with distance from agricultural clearings. These spatial functions were then applied to similar forest/climate combinations outside of the study sites to derive an initial estimate for the Brazilian Amazon. Ninety-one percent of the forest area that burned in the study sites was within the first kilometer of a clearing for the non <span class="hlt">ENSO</span> year and within the first four kilometers for the <span class="hlt">ENSO</span> year. The area of forest burned by understory forest fire during the severe drought (<span class="hlt">ENSO</span>) year (3.9 millions of hectares) was 13 times greater than the area burned during the average rainfall year (0.2 million hectares), and twice the area of annual deforestation rate. Dense forest was, proportionally, the forest area most affected by understory fires during the El Nino year, while understory fires were concentrated in transitional forests during the year of average rainfall. Our estimate of aboveground tree biomass killed by fire ranged from 0.06 Pg to 0.38 Pg during the <span class="hlt">ENSO</span> and from 0,004 Pg to 0,024 Pg during the non <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811455B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811455B"><span><span class="hlt">ENSO</span> effects on stratospheric trace gases: How do we capture reality?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Braesicke, Peter; Kirner, Oliver; Versick, Stefan; Joeckel, Patrick; Stiler, Gabriele</p> <p>2016-04-01</p> <p>The El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon is an important pacemaker for interannual variability in the Earth's atmosphere. <span class="hlt">ENSO</span> impacts on trace gases have been observed and modelled for the stratosphere and the troposphere. However, unambiguous attribution is often difficult due to the limited length of homogenous observational records and thus long-term (decadal) trends are sometimes difficult to detect. Generally <span class="hlt">ENSO</span> impacts in low latitudes are easier to detect, because the response emerges close (temporally and spatially) to the forcing. Moving from low to high latitudes it becomes increasingly difficult to isolate <span class="hlt">ENSO</span> driven variability, due to time-lags involved and many other modes of variability playing a role as well. Here, we use a nudged version of the EMAC chemistry-climate model to evaluate <span class="hlt">ENSO</span> impacts on trace gases over the last 35 years (a so-called Ref-C1SD integration) and contrast the nudged model with its free running counterpart. We use water vapour and ozone observations from the MIPAS instrument on ENVISAT from 2002 to 2012 to test the model performance. Using lagged correlations for the longer model time-series we trace the <span class="hlt">ENSO</span> signal from the tropical lower troposphere to the polar lower and middle stratosphere and provide a framework for simple attribution of the <span class="hlt">ENSO</span> signal in trace gases. This concise characterisation of the <span class="hlt">ENSO</span> impact on trace gases aids improved trend detection in temporally limited time series.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC31E1042A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC31E1042A"><span>Trans-Pacific <span class="hlt">ENSO</span> teleconnections pose a correlated risk to global agriculture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, W. B.; Seager, R.; Cane, M. A.; Baethgen, W.</p> <p>2017-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is a major source of interannual climate variability, particularly in the Pacific Basin. <span class="hlt">ENSO</span> life-cycles tend to evolve over multiple years, as do the associated trans-Pacific <span class="hlt">ENSO</span> teleconnections. This analysis, however, represents the first attempt to characterize the structure of the risk posed by <span class="hlt">ENSO</span> to wheat, maize and soybean production across the Pacific Basin. Our results indicate that most <span class="hlt">ENSO</span> teleconnections relevant for crop flowering seasons are the result of a single trans-Pacific circulation anomaly that develops in boreal summer and persists through the spring. During the late summer and early fall of a developing <span class="hlt">ENSO</span> event, the tropical Pacific forces an atmospheric anomaly in the midlatitudes that spans the Pacific Basin. This teleconnection directly links the soybean and maize growing seasons of the US, Mexico and China. It also connects the wheat growing seasons of Argentina, southern Brazil and Australia. The <span class="hlt">ENSO</span> event peaks in boreal winter, when the atmospheric circulation anomalies intensify and affect maize and soybeans in southeast South America. As the event decays, the <span class="hlt">ENSO</span>-induced circulation anomalies persist through the wheat flowering seasons in China and the US. While the prospect of <span class="hlt">ENSO</span> forcing simultaneous droughts in major food producing regions seems disastrous, there may be a silver lining from the perspective of global food security: trans-Pacific <span class="hlt">ENSO</span> teleconnections to yields are often offsetting between major producing regions in the eastern and western portions of the Pacific Basin. El Niños tend to create good maize and soybean growing conditions in the US and southeast South America, but poor growing conditions in China, Mexico and northeast Brazil. The opposite is true during La Niña. Wheat growing conditions in southeast South America generally have the opposite sign of those in Australia. Finally, we investigate how trade networks interact with this structure of <span class="hlt">ENSO</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913121L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913121L"><span><span class="hlt">ENSO</span> activity during the last climate cycle using IFA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leduc, Guillaume; Vidal, Laurence; Thirumalai, Kaustubh</p> <p>2017-04-01</p> <p>The El Niño / Southern Oscillation (<span class="hlt">ENSO</span>) is the principal mode of interannual climate variability and affects key climate parameters such as low-latitude rainfall variability. Anticipating future <span class="hlt">ENSO</span> variability under anthropogenic forcing is vital due to its profound socioeconomic impact. Fossil corals suggest that 20th century <span class="hlt">ENSO</span> variance is particularly high as compared to other time periods of the Holocene (Cobb et al., 2013, Science), the Last Glacial Maximum (Ford et al., 2015, Science) and the last glacial period (Tudhope et al., 2001, Science). Yet, recent climate modeling experiments suggest an increase in the frequency of both El Niño (Cai et al., 2014, Nature Climate Change) and La Niña (Cai et al., 2015, Nature Climate Change) events. We have expanded an Individual Foraminifera Analysis (IFA) dataset using the thermocline-dwelling N. dutertrei on a marine core collected in the Panama Basin (Leduc et al., 2009, Paleoceanography), that has proven to be a skillful way to reconstruct the <span class="hlt">ENSO</span> (Thirumalai et al., 2013, Paleoceanography). Our new IFA dataset comprehensively covers the Holocene, the last deglaciation and Termination II (MIS5/6) time windows. We will also use previously published data from the Marine Isotope Stage 3 (MIS3). Our dataset confirms variable <span class="hlt">ENSO</span> intensity during the Holocene and weaker activity during LGM than during the Holocene. As a next step, <span class="hlt">ENSO</span> activity will be discussed with respect to the contrasting climatic background of the analysed time windows (millenial-scale variability, Terminations).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..530...51S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..530...51S"><span>A global analysis of the asymmetric effect of <span class="hlt">ENSO</span> on extreme precipitation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Xun; Renard, Benjamin; Thyer, Mark; Westra, Seth; Lang, Michel</p> <p>2015-11-01</p> <p>The global and regional influence of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon on extreme precipitation was analyzed using a global database comprising over 7000 high quality observation sites. To better quantify possible changes in relatively rare design-relevant precipitation quantiles (e.g. the 1 in 10 year event), a Bayesian regional extreme value model was used, which employed the Southern Oscillation Index (SOI) - a measure of <span class="hlt">ENSO</span> - as a covariate. Regions found to be influenced by <span class="hlt">ENSO</span> include parts of North and South America, southern and eastern Asia, South Africa, Australia and Europe. The season experiencing the greatest <span class="hlt">ENSO</span> effect varies regionally, but in most of the <span class="hlt">ENSO</span>-affected regions the strongest effect happens in boreal winter, during which time the 10-year precipitation for |SOI| = 20 (corresponding to either a strong El Niño or La Niña episode) can be up to 50% higher or lower than for SOI = 0 (a neutral phase). Importantly, the effect of <span class="hlt">ENSO</span> on extreme precipitation is asymmetric, with most parts of the world experiencing a significant effect only for a single <span class="hlt">ENSO</span> phase. This finding has important implications on the current understanding of how <span class="hlt">ENSO</span> influences extreme precipitation, and will enable a more rigorous theoretical foundation for providing quantitative extreme precipitation intensity predictions at seasonal timescales. We anticipate that incorporating asymmetric impacts of <span class="hlt">ENSO</span> on extreme precipitation will help lead to better-informed climate-adaptive design of flood-sensitive infrastructure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1339881-changes-sea-salt-emissions-enhance-enso-variability','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1339881-changes-sea-salt-emissions-enhance-enso-variability"><span>Changes in Sea Salt Emissions Enhance <span class="hlt">ENSO</span> Variability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang, Yang; Russell, Lynn M.; Lou, Sijia</p> <p></p> <p>Two 150-year pre-industrial simulations with and without interactive sea salt emissions from the Community Earth System Model (CESM) are performed to quantify the interactions between sea salt emissions and El Niño–Southern Oscillation (<span class="hlt">ENSO</span>). Variations in sea salt emissions over the tropical Pacific Ocean are affected by changing wind speed associated with <span class="hlt">ENSO</span> variability. <span class="hlt">ENSO</span>-induced interannual variations in sea salt emissions result in decreasing (increasing) aerosol optical depth (AOD) by 0.03 over the equatorial central-eastern (western) Pacific Ocean during El Niño events compared to those during La Niña events. These changes in AOD further increase (decrease) radiative fluxes into the atmospheremore » by +0.2 W m -2 (-0.4 W m -2) over the tropical eastern (western) Pacific. Thereby, sea surface temperature increases (decreases) by 0.2–0.4 K over the tropical eastern (western) Pacific Ocean during El Niño compared to La Niña events and enhances <span class="hlt">ENSO</span> variability by 10%. The increase in <span class="hlt">ENSO</span> amplitude is a result of systematic heating (cooling) during the warm (cold) phase, of <span class="hlt">ENSO</span> in the eastern Pacific. Interannual variations in sea salt emissions then produce the anomalous ascent (subsidence) over the equatorial eastern (western) Pacific between El Niño and La Niña events, which is a result of heating anomalies. Due to variations in sea salt emissions, the convective precipitation is enhanced by 0.6–1.2 mm day -1 over the tropical central-eastern Pacific Ocean and weakened by 0.9–1.5 mm day -1 over the Maritime Continent during El Niño compared to La Niña events, enhancing the precipitation variability over the tropical Pacific.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A43D2474L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A43D2474L"><span>A Teleconnection between the West Siberian Plain and the <span class="hlt">ENSO</span> Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liess, S.; Agrawal, S.; Chatterjee, S.; Kumar, V.</p> <p>2017-12-01</p> <p>This study presents a mechanism that links the El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) to extratropical waves that are deflected from the Northern Hemisphere polar regions and travel southeastward over Central Asia toward the west Pacific warm pool during northern winter. The initial wave pattern resembles the well-known East Atlantic-West Russia pattern. Here we show its influence on the <span class="hlt">ENSO</span> region. We identify a tripole pattern between the West Siberian Plain and the two centers of action of <span class="hlt">ENSO</span> with a graph-based approach. It indicates that the background state of <span class="hlt">ENSO</span> with respect to global sea level pressure (SLP) has a significant negative correlation to the West Siberian Plain. The correlation with the background state, which is defined by the sum of the two centers of action of <span class="hlt">ENSO</span>, is higher than each of the pairwise correlations with either of the <span class="hlt">ENSO</span> centers alone. We define the centers with a clustering algorithm that detects regions with similar characteristics. The normalized monthly SLP time series for the two centers of <span class="hlt">ENSO</span> (around Darwin, Australia and Tahiti) are area-averaged and the sum of both regions is considered as the background state of <span class="hlt">ENSO</span>. This wave train can be detected throughout the troposphere and the lower stratosphere. Its origins can be traced back to atmospheric wave activity triggered by convection over the subtropical North Atlantic that emanates wave activity toward the West Siberian Plain. The same wave train also propagates to the central Pacific Ocean around Tahiti and can be used to predict the background state over the <span class="hlt">ENSO</span> region. This background state also modifies the subtropical bridge between the tropical east Pacific and the subtropical North Atlantic, thus leading to a circumglobal wave train.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.5080..180S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.5080..180S"><span>Active-matrix OLED using 150°C <span class="hlt">a-Si</span> TFT backplane built on flexible plastic substrate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarma, Kalluri R.; Chanley, Charles; Dodd, Sonia R.; Roush, Jared; Schmidt, John; Srdanov, Gordana; Stevenson, Matthew; Wessel, Ralf; Innocenzo, Jeffrey; Yu, Gang; O'Regan, Marie B.; MacDonald, W. A.; Eveson, R.; Long, Ke; Gleskova, Helena; Wagner, Sigurd; Sturm, James C.</p> <p>2003-09-01</p> <p>Flexible displays fabricated using plastic substrates have a potential for being very thin, light weight, highly rugged with greatly minimized propensity for breakage, roll-to-roll manufacturing and lower cost. The emerging OLED display media offers the advantage of being a solid state and rugged structure for flexible displays in addition to the many potential advantages of an AM OLED over the currently dominant AM LCD. The current high level of interest in flexible displays is facilitating the development of the required enabling technologies which include development of plastic substrates, low temperature active matrix device and backplane fabrication, and display <span class="hlt">packaging</span>. In the following we will first discuss our development efforts in the PEN based plastic substrates, active matrix backplane technology, low temperature (150°C) <span class="hlt">a-Si</span> TFT devices and an AM OLED test chip used for evaluating various candidate designs. We will then describe the design, fabrication and successful evaluation and demonstration of a 64x64 pixel AM OLED test display using <span class="hlt">a-Si</span> TFT backplane fabricated at 150°C on the flexible plastic substrate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PrOce.140....1D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PrOce.140....1D"><span><span class="hlt">ENSO</span> and anthropogenic impacts on phytoplankton diversity in tropical coastal waters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doan-Nhu, Hai; Nguyen-Ngoc, Lam; Nguyen, Chi-Thoi</p> <p>2016-01-01</p> <p>16-year phytoplankton data were analysed to assess <span class="hlt">ENSO</span> and anthropogenic impacts on biodiversity and community structure at 3 locations (Nha-Trang and Phan-Thiet Bays and near Phu-Qui Island) in South Centre Viet Nam to understand (1) the primary scales of change in phytoplankton community structure, and traditional and taxonomic diversity indices; (2) the significance of environmental changes and/or climate variability on phytoplankton diversity; and (3) the usefulness of these long-term data for analysing future impacts of anthropogenic and climate changes. Traditional and taxonomic diversity indices were compared and tested in linkage with environmental conditions and <span class="hlt">ENSO</span>. Nutrient data indicated stronger environmental impacts in Phan-Thiet Bay, milder in Nha-Trang Bay and less noticeable near Phu-Qui Island. There were measurable impacts of both anthropogenic and <span class="hlt">ENSO</span> on phytoplankton at different locations in various parameters, e.g. species number, diversity and community structures. The lowest diversity was recorded in the most anthropogenically impacted site, Phan-Thiet Bay. Although a stronger impact on phytoplankton was recorded in <span class="hlt">ENSO</span> year in Phan Thiet Bay, quantitative separation between anthropogenic and <span class="hlt">ENSO</span> impacts using phytoplankton biodiversity indices was impossible. In the waters with less anthropogenic impacts, <span class="hlt">ENSO</span> effects on taxonomic diversity was better indicated by negative phytoplankton responses to the ONI index (Nha-Trang Bay) and recovery of phytoplankton after the <span class="hlt">ENSO</span> events (near Phu-Qui Island). Among the diversity indices, the taxonomic diversity indices (e.g. Δ+ and Λ+) better described impacts of <span class="hlt">ENSO</span> than the traditional ones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPC34B2178C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPC34B2178C"><span>The Role of Reversed Equatorial Zonal Transport in Terminating an <span class="hlt">ENSO</span> Event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, H. C.; Hu, Z. Z.; Huang, B.; Sui, C. H.</p> <p>2016-02-01</p> <p>In this study, we demonstrate that a sudden reversal of anomalous equatorial zonal current at the peaking <span class="hlt">ENSO</span> phase triggers the rapid termination of an <span class="hlt">ENSO</span> event. Throughout an <span class="hlt">ENSO</span> cycle, the anomalous equatorial zonal current is strongly controlled by the concavity of the anomalous thermocline meridional structure near the equator. During the <span class="hlt">ENSO</span> developing phase, the anomalous zonal current in the central and eastern Pacific generally enhances the <span class="hlt">ENSO</span> growth through its zonal SST advection. In the mature phase of <span class="hlt">ENSO</span>, however, the equatorial thermocline depth anomalies are reflected in the eastern Pacific and slowly propagate westward off the equator in both hemispheres. As a result, the concavity of the thermocline anomalies near the equator is reversed, i.e., the off-equatorial thermocline depth anomalies become higher than that on the equator for El Niño events and lower for La Niño events. This meridional change of thermocline structure reverses zonal transport rapidly in the central-to-eastern equatorial Pacific, which weakens the <span class="hlt">ENSO</span> SST anomalies by reversed advection. More importantly, the reversed zonal mass transport weakens the existing zonal tilting of equatorial thermocline and suppresses the thermocline feedback. Both processes are concentrated in the eastern equatorial Pacific and can be effective on subseasonal time scales. These current reversal effects are built-in to the <span class="hlt">ENSO</span> peak phase and independent of the zonal wind effect on thermocline slope. It functions as an oceanic control on <span class="hlt">ENSO</span> evolution during both El Niño and La Niña events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.3420X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.3420X"><span>The seasonality and geographic dependence of <span class="hlt">ENSO</span> impacts on U.S. surface ozone variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Li; Yu, Jin-Yi; Schnell, Jordan L.; Prather, Michael J.</p> <p>2017-04-01</p> <p>We examine the impact of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on surface ozone abundance observed over the continental United States (U.S.) during 1993-2013. The monthly ozone decreases (increases) during El Niño (La Niña) years with amplitude up to 1.8 ppb per standard deviation of Niño 3.4 index. The largest <span class="hlt">ENSO</span> influences occur over two southern U.S. regions during fall when the <span class="hlt">ENSO</span> develops and over two western U.S. regions during the winter to spring after the <span class="hlt">ENSO</span> decays. <span class="hlt">ENSO</span> affects surface ozone via chemical processes during warm seasons in southern regions, where favorable meteorological conditions occur, but via dynamic transport during cold seasons in western regions, where the <span class="hlt">ENSO</span>-induced circulation variations are large. The geographic dependence and seasonality of the <span class="hlt">ENSO</span> impacts imply that regulations regarding air quality and its exceedance need to be adjusted for different seasons and U.S. regions to account for the <span class="hlt">ENSO</span>-driven patterns in surface ozone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25820758','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25820758"><span>Synthesis and characterization of (18)F-labeled active site inhibited factor VII (<span class="hlt">ASIS</span>).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Erlandsson, Maria; Nielsen, Carsten H; Jeppesen, Troels E; Kristensen, Jesper B; Petersen, Lars C; Madsen, Jacob; Kjaer, Andreas</p> <p>2015-05-15</p> <p>Activated factor VII blocked in the active site with Phe-Phe-Arg-chloromethyl ketone (active site inhibited factor VII (<span class="hlt">ASIS</span>)) is a 50-kDa protein that binds with high affinity to its receptor, tissue factor (TF). TF is a transmembrane glycoprotein that plays an important role in, for example, thrombosis, metastasis, tumor growth, and tumor angiogenesis. The aim of this study was to develop an (18)F-labeled <span class="hlt">ASIS</span> derivative to assess TF expression in tumors. Active site inhibited factor VII was labeled using N-succinimidyl-4-[(18)F]fluorobenzoate, and the [(18)F]<span class="hlt">ASIS</span> was purified on a PD-10 desalting column. The radiochemical yield was 25 ± 6%, the radiochemical purity was >97%, and the pseudospecific radioactivity was 35 ± 9 GBq/µmol. The binding efficacy was evaluated in pull-down experiments, which monitored the binding of unlabeled <span class="hlt">ASIS</span> and [(18)F]<span class="hlt">ASIS</span> to TF and to a specific anti-factor VII antibody (F1A2-mAb). No significant difference in binding efficacy between [(18)F]<span class="hlt">ASIS</span> and <span class="hlt">ASIS</span> could be detected. Furthermore, [(18)F]<span class="hlt">ASIS</span> was relatively stable in vitro and in vivo in mice. In conclusion, [(18)F]<span class="hlt">ASIS</span> has for the first time been successfully synthesized as a possible positron emission tomography tracer to image TF expression levels. In vivo positron emission tomography studies to evaluate the full potential of [(18)F]<span class="hlt">ASIS</span> are in progress. Copyright © 2015 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNG41A0110R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNG41A0110R"><span><span class="hlt">ENSO</span> Dynamics and Trends, AN Alternate View</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rojo Hernandez, J. D.; Lall, U.; Mesa, O. J.</p> <p>2017-12-01</p> <p>El Niño - Southern Oscillation (<span class="hlt">ENSO</span>) is the most important inter-annual climate fluctuation on a planetary level with great effects on the hydrological cycle, agriculture, ecosystems, health and society. This work demonstrates the use of the Non-Homogeneus hidden Markov Models (NHMM) to characterize <span class="hlt">ENSO</span> using a set of discrete states with variable transition probabilities matrix using the data of sea surface temperature anomalies (SSTA) of the Kaplan Extended SST v2 between 120E -90W, 15N-15S from Jan-1856 to Dec-2016. <span class="hlt">ENSO</span> spatial patterns, their temporal distribution, the transition probabilities between patterns and their temporal evolution are the main results of the NHHMM applied to <span class="hlt">ENSO</span>. The five "hidden" states found appear to represent the different "Flavors" described in the literature: the Canonical El Niño, Central El Niño, a Neutral state, Central La Niña and the Canonical Niña. Using the whole record length of the SSTA it was possible to identify trends in the dynamic system, with a decrease in the probability of occurrence of the cold events and a significant increase of the warm events, in particular of Central El Niño events whose probability of occurrence has increased Dramatically since 1960 coupled with increases in global temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JESS..126...30D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JESS..126...30D"><span>Study of the global and regional climatic impacts of <span class="hlt">ENSO</span> magnitude using SPEEDY AGCM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dogar, Muhammad Mubashar; Kucharski, Fred; Azharuddin, Syed</p> <p>2017-03-01</p> <p><span class="hlt">ENSO</span> is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of <span class="hlt">ENSO</span> events have increased over the last few decades resulting in a need to study climatic impacts of <span class="hlt">ENSO</span> magnitude both at global and regional scales. Hence, to better understand the impact of <span class="hlt">ENSO</span> amplitude over the tropical and extratropical regions focussing on the Asian and African domains, <span class="hlt">ENSO</span> sensitivity experiments are conducted using ICTPAGCM (`SPEEDY'). It is anticipated that the tropical Pacific SST forcing will be enough to produce <span class="hlt">ENSO</span>-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of <span class="hlt">ENSO</span> over the Pacific, North and South America and African regions very well. However, it underestimates <span class="hlt">ENSO</span> teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent <span class="hlt">ENSO</span>-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air-sea coupling is also required for better representation of <span class="hlt">ENSO</span>-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that <span class="hlt">ENSO</span> impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of <span class="hlt">ENSO</span> causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that <span class="hlt">ENSO</span> magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant impact</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1498X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1498X"><span>Mean state dependence of <span class="hlt">ENSO</span> diversity resulting from an intermediate coupled model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Ruihuang; Jin, Fei-Fei; Mu, Mu</p> <p>2016-04-01</p> <p><span class="hlt">ENSO</span> diversity is referred to the event-to-event differences in the amplitude, longitudinal location of maximum sea surface temperature (SST) anomalies and evolutional mechanisms, as manifested in both observation data and climate model simulations. Previous studies argued that westerly wind burst (WWB) has strong influence on <span class="hlt">ENSO</span> diversity. Here, we bring evidences, from a modified intermediate complexity Zebiak-Cane (ZC) coupled model, to illustrate that the <span class="hlt">ENSO</span> diversity is also determined by the mean states. Stabilities of the linearized ZC model reveal that the mean state with weak (strong) wind stress and deep (shallow) thermocline prefers <span class="hlt">ENSO</span> variation in the equitorial eastern (central) Pacific with a four-year (two-year) period. Weak wind stress and deep thermocline make the thermocline (TH) feedback the dominant contribution to the growth of <span class="hlt">ENSO</span> SST anomalies, whereas the opposite mean state favors the zonal advective (ZA) feedback. Different leading dynamical SST-controller makes <span class="hlt">ENSO</span> display its diversity. In a mean state that resembles the recent climate in the tropical Pacific, the four-year and two-year <span class="hlt">ENSO</span> variations coexist with similar growth rate. Even without WWB forcing, the nonlinear integration results with adjusted parameters in this special mean state also present at least two types of El Niño, in which the maximum warming rates are contributed by either TH or ZA feedback. The consistency between linear and nonlinear model results indicates that the <span class="hlt">ENSO</span> diversity is dependent on the mean states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920023015&hterms=marriage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmarriage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920023015&hterms=marriage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmarriage"><span>Modeling of SSME fuel preburner <span class="hlt">ASI</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liang, Pak-Yan</p> <p>1992-01-01</p> <p>The Augmented Spark Ignitor (<span class="hlt">ASI</span>) is a LOX/H2/electrical spark system that functions as an ignition source and sustainer for stable combustion. It is used in the Space Shuttle Main Engine (SSME) preburner combustor, the SMME main combustion chamber, the J-1 and J-2 engines, as well as proposed designs of the Space Transportation Main Engine (STME) main combustor and gas generators. An undertaking to characterize the flow of the <span class="hlt">ASI</span> is documented. The code consists of a marriage of the Implicit-Continuous Eulerian/Arbitrary Lagrangian Code (ICE-ALE) Navier-Stokes solver with the Volume-of-Fluid (VOF) Methodology for tracking of two immiscible fluids with sharp discontinuities. Spray droplets are represented by discrete numerical parcels tracked in a Lagrangian fashion. Numerous physical sub-models are also incorporated to describe the processes of atomization, droplet collision, droplet breakup, evaporation, and droplet and gas phase turbulence. An equilibrium chemistry model accounting for 8 active gaseous species is also used. Taking advantage of this symmetry plane, half of the actual <span class="hlt">ASI</span> is modeled with a 3-D grid that geometrically resolves the LOX ports, the spark plug locations, and the hydrogen injection slots.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5504352','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5504352"><span>Greening of the Sahara suppressed <span class="hlt">ENSO</span> activity during the mid-Holocene</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pausata, Francesco S. R.; Zhang, Qiong; Muschitiello, Francesco; Lu, Zhengyao; Chafik, Léon; Niedermeyer, Eva M.; Stager, J. Curt; Cobb, Kim M.; Liu, Zhengyu</p> <p>2017-01-01</p> <p>The evolution of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) during the Holocene remains uncertain. In particular, a host of new paleoclimate records suggest that <span class="hlt">ENSO</span> internal variability or other external forcings may have dwarfed the fairly modest <span class="hlt">ENSO</span> response to precessional insolation changes simulated in climate models. Here, using fully coupled ocean-atmosphere model simulations, we show that accounting for a vegetated and less dusty Sahara during the mid-Holocene relative to preindustrial climate can reduce <span class="hlt">ENSO</span> variability by 25%, more than twice the decrease obtained using orbital forcing alone. We identify changes in tropical Atlantic mean state and variability caused by the momentous strengthening of the West Africa Monsoon (WAM) as critical factors in amplifying ENSO’s response to insolation forcing through changes in the Walker circulation. Our results thus suggest that potential changes in the WAM due to anthropogenic warming may influence <span class="hlt">ENSO</span> variability in the future as well. PMID:28685758</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A44E..04F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A44E..04F"><span>Increasing <span class="hlt">ENSO</span>-Driven Drought and Wildfire Risks in a Warming Climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fasullo, J.; Otto-Bliesner, B. L.; Stevenson, S.</p> <p>2015-12-01</p> <p><span class="hlt">ENSO</span>-related teleconnections occurring in the transient climate states of the 20th and 21st centuries are examined using the NCAR CESM1-CAM5 Large Ensemble (LE). A focus is given to quantifying the changing nature of related variability in a warming climate, the statistical robustness of which is enhanced by the numerous members of the LE (presently ~40). It is found that while the dynamical components of <span class="hlt">ENSO</span>'s teleconnections weaken considerably in a warming world, associated variability over land is in many cases sustained by changes in the background state, such as for rainfall due to the background rise in specific humidity. In some fields, particularly those associated with associated with thermal stress (e.g. drought and wildfire), <span class="hlt">ENSO</span>-related variance increases dramatically. This, combined with the fact that <span class="hlt">ENSO</span> variance itself increases in a warming climate in the LE, contributes to dramatic projected increases in <span class="hlt">ENSO</span>-driven drought and wildfire risks in a warming world.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP33A1316P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP33A1316P"><span>Fossil Coral Records of <span class="hlt">ENSO</span> during the Last Glacial Period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Partin, J. W.; Taylor, F. W.; Shen, C. C.; Edwards, R. L.; Quinn, T. M.; DiNezro, P.</p> <p>2017-12-01</p> <p>Only a handful of paleoclimate records exist that can resolve interannual changes, and hence El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) variability, during the last glacial period, a time of altered mean climate. The few existing data suggest reduced <span class="hlt">ENSO</span> variability compared to the Holocene, possibly due to a weaker zonal sea surface temperature gradient across the tropical Pacific and/or a deeper thermocline in the eastern tropical Pacific. Our goal is to add crucial data to this extremely limited subset using sub-annually resolved fossil corals that grew during this time period to reconstruct <span class="hlt">ENSO</span>. We seek to recover fossil corals from Vanuatu, SW Pacific (16°S, 167°E) with the objective of using coral δ18O to reconstruct changes in the <span class="hlt">ENSO</span> during and near the Last Glacial Maximum (LGM). Modern δ18O coral records from Vanuatu show a high degree of skill in capturing <span class="hlt">ENSO</span> variability, making it a suitable site for reconstructing <span class="hlt">ENSO</span> variability. We have custom designed and are building a drill system that can rapidly core many 0-25 m holes resulting in much more meters of penetration than achieved by previous land-based reef drilling. As the new drill system is extremely portable and can be quickly relocated by workers without landing craft or vehicles, it is time and cost efficient. Because the proposed drilling sites have uplifted extremely fast, 7 mm/year, the LGM shoreline has been raised from 120-140 m depth to within a depth range of 10 below to 20 m above present sea level. This enables all the drilling to be within the time range of interest ( 15-25 ka). A last advantage is that the LGM corals either are still submersed in seawater or emerged only within the last 2000 years at the uplift rate of 7 mm/yr. This greatly reduces the chances of disruption of the original climate signal because sea water is less diagenetically damaging than meteoric water in the mixed, phreatic, or vadose zones. LGM coral records will enable us to compare the proxy variability</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..60.2379A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..60.2379A"><span>Variability of lightning activity over India on <span class="hlt">ENSO</span> time scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahmad, Adnan; Ghosh, Mili</p> <p>2017-12-01</p> <p><span class="hlt">ENSO</span>, the reliable indicator of inter-annual climate variation of the ocean-atmosphere system in the tropical Pacific region, can affect the overall lightning activity which is another atmospheric phenomenon. In the present study, the impact of the <span class="hlt">ENSO</span> on the total lightning activity over India has been studied for the period 2004-2014. During the El-Nino period (July 2004-April 2005 and July 2009-April 2010), total number of lightning flashes increased by 10% and 18% respectively and during La-Nina period (July 2010-April 2011 and August 2011 to March 2012), the total number of lightning flashes decreased approximately by 19% and 28% respectively as compared to the mean of corresponding period (2004-14) of the Non-<span class="hlt">ENSO</span>. Seasonal variation of flash density is also examined for the El-Nino and La-Nina period. The result shows that in the El-Nino period of the pre-monsoon and monsoon seasons, there is an increment in the flash density approximately by 48% and 9% respectively than the Non-<span class="hlt">ENSO</span> and the spatial variation also having high flash density along the foot of Himalayas region. In the post-monsoon season, there is a marginal change in the flash density between El-Nino and the Non-<span class="hlt">ENSO</span>. In the winter season, there is an increment in flash density in the El-Nino period approximately by 45% than the Non-<span class="hlt">ENSO</span>. In the La-Nina period of the pre-monsoon and monsoon seasons, there is the decrement in the flash density approximately by the 44% and 24% respectively than the Non-<span class="hlt">ENSO</span>. In the Post-monsoon season and winter season of La-Nina, the flash density is increased by about 24% and 33% over India. These findings can be applied to do proper planning of lightning induced hazard mitigation as lightning is of one of the major natural disasters of India.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/2002017','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/2002017"><span><span class="hlt">ENSO</span> events in the northern Gulf of Alaska, and effects on selected marine fisheries</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bailey, K.M.; Macklin, S.A.; Reed, R.K.; Brodeur, R.D.; Ingraham, W.J.; Piatt, John F.; Shima, M.; Francis, R.C.; Anderson, P.J.; Royer, T.C.; Hollowed, A.; Somerton, D.A.; Wooster, W.S.</p> <p>1995-01-01</p> <p>The 1991-93 El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) event first appeared in the northern Gulf of Alaska in autumn 1991 with warm sea-surface temperatures. In winter 1992, there were pulses of increased sea level and anomalous circulation. El Nino conditions persisted at least through summer 1993. The effects of this <span class="hlt">ENSO</span> event on major groundfish species and Pacific herring in the northern Gulf of Alaska were examined and compared with the effects of previous <span class="hlt">ENSO</span> events. There is little evidence that the 1991-93 or 1982-83 <span class="hlt">ENSO</span> events affected landings of walleye pollock, Pacific cod, Pacific halibut, or arrowtooth flounder. Some changes in distribution of groundfish species were observed in 1993, but the effect was similar to changes observed in non-<span class="hlt">ENSO</span> warm years. In general, warm ocean conditions have a positive effect on recruitment of northern stocks, but <span class="hlt">ENSO</span> events appear to have an inconsistent effect on year-class strength within species and among different species. For example, strong year classes of halibut and arrowtooth flounder sometimes, but not always, coincide with <span class="hlt">ENSO</span> events; <span class="hlt">ENSO</span> events are associated with moderate to weak year classes of cod and pollock. However, post-<span class="hlt">ENSO</span> warm years often are associated with strong recruitment of many groundfish species. Major changes have occurred in the Gulf of Alaska ecosystem since 1977. The influence of the 1976 <span class="hlt">ENSO</span> event in precipitating these changes and the role of the frequency or strength of subsequent El Nino events is presently unknown. Herring and other stocks of small pelagic fishes may be more affected by <span class="hlt">ENSO</span> events. In particular, decreased catches, recruitment, and weight-at-age of herring are sometimes associated with <span class="hlt">ENSO</span> events. Furthermore, a variety of seabirds which feed mostly on pelagic forage fishes or the pelagic juvenile stages of groundfish suffered widespread mortalities and breeding failures in the Gulf of Alaska during the <span class="hlt">ENSO</span> years of 1983 and 1993. These effects on seabirds</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7556W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7556W"><span>Is <span class="hlt">ENSO</span> part of an Indo-Pacific phenomenon?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieners, Claudia; de Ruijter, Wilhelmus; Dijkstra, Henk</p> <p>2015-04-01</p> <p>The Seychelles Dome (SD) - a thermocline ridge in the West Indian Ocean - is a dynamically active region with a strong Sea Surface Temperature (SST)-atmosphere coupling and located at the origin of the Madden-Julian Oscillation. Analysis of observational data suggests that it might influence El Niño occurrence and evolution at a lead time of 1.5 years. We find a negative correlation between SD SST in boreal summer and Nino3.4 SST about 18 months later. Such a correlation might be a mere side-effect of the fact that <span class="hlt">ENSO</span> has influence on the SD - El Niño (La Niña) is followed by a warm (cool) SD after about 3-6 months - and of the cyclicity of <span class="hlt">ENSO</span> with a preferred period of about 4 years. However, we find the correlation to be significantly stronger than one would expect in that case, implying that the SD contains information linearly independent from <span class="hlt">ENSO</span>. A Multi-channel Singular Spectrum analysis (MSSA) on tropical SST, zonal wind and zonal wind variability reveals three significant oscillations. All of these show <span class="hlt">ENSO</span>-like behaviour in the Pacific Ocean, with East Pacific SST anomalies being followed by anomalies of the same sign in the SD region after 3-5 months. Wind patterns propagate from the Indian to the Pacific Ocean. These findings suggest that the Indian and Pacific Oceans act as a unified system. The slower two oscillations, with periods around 4 years, have the strongest <span class="hlt">ENSO</span> signal in the East Pacific (like a `Cold Tongue El Niño'). Compared to them, the fastest oscillation, with a period of 2.5 years, has a stronger signal in the Central Pacific (more resembling a `Warm Pool El Niño'). Because of the short period of the fastest mode, the time elapsed between an SD anomaly and the following <span class="hlt">ENSO</span> anomaly (of opposite sign) is only 11 months - much less than the 18 months lag at which the correlation between SD and <span class="hlt">ENSO</span> is minimal. This suggests that while the Cold Tongue El Niño's tend to be preceded by a cool SD event at a lead time suitable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28729610','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28729610"><span>Mean Bias in Seasonal Forecast Model and <span class="hlt">ENSO</span> Prediction Error.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Seon Tae; Jeong, Hye-In; Jin, Fei-Fei</p> <p>2017-07-20</p> <p>This study uses retrospective forecasts made using an APEC Climate Center seasonal forecast model to investigate the cause of errors in predicting the amplitude of El Niño Southern Oscillation (<span class="hlt">ENSO</span>)-driven sea surface temperature variability. When utilizing Bjerknes coupled stability (BJ) index analysis, enhanced errors in <span class="hlt">ENSO</span> amplitude with forecast lead times are found to be well represented by those in the growth rate estimated by the BJ index. <span class="hlt">ENSO</span> amplitude forecast errors are most strongly associated with the errors in both the thermocline slope response and surface wind response to forcing over the tropical Pacific, leading to errors in thermocline feedback. This study concludes that upper ocean temperature bias in the equatorial Pacific, which becomes more intense with increasing lead times, is a possible cause of forecast errors in the thermocline feedback and thus in <span class="hlt">ENSO</span> amplitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP23D..06L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP23D..06L"><span><span class="hlt">ENSO</span> activity during the last climate cycle using Individual Foraminifera Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leduc, G.; Vidal, L.; Thirumalai, K.</p> <p>2017-12-01</p> <p>The El Niño / Southern Oscillation (<span class="hlt">ENSO</span>) is the principal mode of interannual climate variability and affects key climate parameters such as low-latitude rainfall variability. Recent climate modeling experiments tend to suggest an increase in the frequency of both El Niño and La Niña events in the future, but these results remain model-dependent and require to be validated by paleodata-model comparisons. Fossil corals indicate that the <span class="hlt">ENSO</span> variance during the 20th century is particularly high as compared to other time periods of the Holocene. Beyond the Holocene, however, little is known on past <span class="hlt">ENSO</span> changes, which makes difficult to test paleoclimate model simulations that are used to study the <span class="hlt">ENSO</span> sensitivity to various types of forcings. We have expanded an Individual Foraminifera Analysis (IFA) dataset using the thermocline-dwelling N. dutertrei on a marine core collected in the Panama Basin (Leduc et al., 2009), that has proven to be a skillful way to reconstruct the <span class="hlt">ENSO</span> (Thirumalai et al., 2013). Our new IFA dataset comprehensively covers the Holocene, allowing to verify how the IFA method compares with <span class="hlt">ENSO</span> reconstructions using corals. The dataset then extends back in time to Marine Isotope Stage 6 (MIS), with a special focus the last deglaciation and Termination II (MIS5/6) time windows, as well as key time periods to tests the sensitivity of <span class="hlt">ENSO</span> to ice volume and orbital parameters. The new dataset confirms variable <span class="hlt">ENSO</span> activity during the Holocene and weaker activity during LGM than during the Holocene, as a recent isotope-enabled climate model simulations of the LGM suggests (Zhu et al., 2017). Such pattern is reproduced for the Termination II. Leduc, G., L. Vidal, O. Cartapanis, and E. Bard (2009), Modes of eastern equatorial Pacific thermocline variability: Implications for <span class="hlt">ENSO</span> dynamics over the last glacial period, Paleoceanography, 24, PA3202, doi:10.1029/2008PA001701. Thirumalai, K., J. W. Partin, C. S. Jackson, and T. M. Quinn (2013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1343183-dms-role-enso-cycle-tropics-dms-role-enso-cycle-tropics','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1343183-dms-role-enso-cycle-tropics-dms-role-enso-cycle-tropics"><span>DMS role in <span class="hlt">ENSO</span> cycle in the tropics: DMS Role in <span class="hlt">ENSO</span> Cycle in Tropics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, Li; Cameron-Smith, Philip; Russell, Lynn M.</p> <p></p> <p>We examined the multiyear mean and variability of dimethyl sulfide (DMS) and its relationship to sulfate aerosols, as well as cloud microphysical and radiative properties. We conducted a 150 year simulation using preindustrial conditions produced by the Community Earth System Model embedded with a dynamic DMS module. The model simulated the mean spatial distribution of DMS emissions and burden, as well as sulfur budgets associated with DMS, SO2, H2SO4, and sulfate that were generally similar to available observations and inventories for a variety of regions. Changes in simulated sea-to-air DMS emissions and associated atmospheric abundance, along with associated aerosols andmore » cloud and radiative properties, were consistently dominated by El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) cycle in the tropical Pacific region. Simulated DMS, aerosols, and clouds showed a weak positive feedback on sea surface temperature. This feedback suggests a link among DMS, aerosols, clouds, and climate on interannual timescales. The variability of DMS emissions associated with <span class="hlt">ENSO</span> was primarily caused by a higher variation in wind speed during La Niña events. The simulation results also suggest that variations in DMS emissions increase the frequency of La Niña events but do not alter <span class="hlt">ENSO</span> variability in terms of the standard deviation of the Niño 3 sea surface temperature anomalies.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18718727','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18718727"><span>Validation of the Spanish Addiction Severity Index Multimedia Version (S-<span class="hlt">ASI</span>-MV).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Butler, Stephen F; Redondo, José Pedro; Fernandez, Kathrine C; Villapiano, Albert</p> <p>2009-01-01</p> <p>This study aimed to develop and test the reliability and validity of a Spanish adaptation of the <span class="hlt">ASI</span>-MV, a computer administered version of the Addiction Severity Index, called the S-<span class="hlt">ASI</span>-MV. Participants were 185 native Spanish-speaking adult clients from substance abuse treatment facilities serving Spanish-speaking clients in Florida, New Mexico, California, and Puerto Rico. Participants were administered the S-<span class="hlt">ASI</span>-MV as well as Spanish versions of the general health subscale of the SF-36, the work and family unit subscales of the Social Adjustment Scale Self-Report, the Michigan Alcohol Screening Test, the alcohol and drug subscales of the Personality Assessment Inventory, and the Hopkins Symptom Checklist-90. Three-to-five-day test-retest reliability was examined along with criterion validity, convergent/discriminant validity, and factorial validity. Measurement invariance between the English and Spanish versions of the <span class="hlt">ASI</span>-MV was also examined. The S-<span class="hlt">ASI</span>-MV demonstrated good test-retest reliability (ICCs for composite scores between .59 and .93), criterion validity (rs for composite scores between .66 and .87), and convergent/discriminant validity. Factorial validity and measurement invariance were demonstrated. These results compared favorably with those reported for the original interviewer version of the <span class="hlt">ASI</span> and the English version of the <span class="hlt">ASI</span>-MV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A41C2284S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A41C2284S"><span>Increased frequency of <span class="hlt">ENSO</span>-related hydroclimate extremes in a warming climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Q.; Miao, C.; AghaKouchak, A.</p> <p>2017-12-01</p> <p>Global warming will likely alter surface warming in tropical Pacific regions, leading to changes in the characteristics of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) characteristics and an incresed frequency of extreme <span class="hlt">ENSO</span> events. The <span class="hlt">ENSO</span>-related climatic variation and associated impacts will likely be modified in a warmer climatic state. However, little is known about the effect of changes in <span class="hlt">ENSO</span> teleconnections with regard to future dry and wet conditions over land around the globe, especially outside tropical regions. We used the model simulations of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) for different twenty-first-century emission scenarios (RCP 4.5 and RCP 8.5) to investigate the changes in the <span class="hlt">ENSO</span>' teleconnection on dry/wet condition over global land. Our results show that 64.64% and 38.12% of 181 river basins studied are expected to experience an increase in the frequency of unusually wet/dry events forced by both <span class="hlt">ENSO</span> phases under the RCP 4.5 and 8.5, respectively. The anomalous precipitation variability forced by <span class="hlt">ENSO</span> events will be intensified through a "wet-get-wetter, dry-get-drier" mechanism over west North America, South America, central Asia, and west Asia. More than 850 million people are at risk of exposure to unusually dry/wet events. There is a potential increased risk of high-intensity dry/wet events, with an increase/decrease in the 50-year return level of SPI value for drying/wetting regions. These results have important implications for disaster evaluation and related policies and for appropriate engineering design.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990106571&hterms=asian+american&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dasian%2Bamerican','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990106571&hterms=asian+american&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dasian%2Bamerican"><span>Global Precipitation Patterns Associated with <span class="hlt">ENSO</span> and Tropical Circulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, Scott; Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric</p> <p>1999-01-01</p> <p>Tropical precipitation and the accompanying latent heat release is the engine that drives the global circulation. An increase or decrease in rainfall in the tropics not only leads to the local effects of flooding or drought, but contributes to changes in the large scale circulation and global climate system. Rainfall in the tropics is highly variable, both seasonally (monsoons) and interannually (<span class="hlt">ENSO</span>). Two experimental observational data sets, developed under the auspices of the Global Precipitation Climatology Project (GPCP), are used in this study to examine the relationships between global precipitation and <span class="hlt">ENSO</span> and extreme monsoon events over the past 20 years. The V2x79 monthly product is a globally complete, 2.5 deg x 2.5 deg, satellite-gauge merged data set that covers the period 1979 to the present. Indices based on patterns of satellite-derived rainfall anomalies in the Pacific are used to analyze the teleconnections between <span class="hlt">ENSO</span> and global precipitation, with emphasis on the monsoon systems. It has been well documented that dry (wet) Asian monsoons accompany warm (cold) <span class="hlt">ENSO</span> events. However, during the summer seasons of the 1997/98 <span class="hlt">ENSO</span> the precipitation anomalies were mostly positive over India and the Bay of Bengal, which may be related to an epoch-scale variability in the Asian monsoon circulation. The North American monsoon may be less well linked to <span class="hlt">ENSO</span>, but a positive precipitation anomaly was observed over Mexico around the September following the 1997/98 event. For the twenty-year record, precipitation and SST patterns in the tropics are analyzed during wet and dry monsoons. For the Asian summer monsoon, positive rainfall anomalies accompany two distinct patterns of tropical precipitation and a warm Indian Ocean. Negative anomalies coincide with a wet Maritime Continent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5099569','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5099569"><span>Direct and indirect <span class="hlt">ENSO</span> modulation of winter temperature over the Asian–Pacific–American region</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Leung, Marco Y. T.; Zhou, Wen</p> <p>2016-01-01</p> <p>In this study, the direct and indirect atmospheric responses over the Asian–Pacific–American region to the El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) are documented. Since <span class="hlt">ENSO</span> is likely to induce the northward displacement of the East Asian trough (NDEAT), some of the influence of <span class="hlt">ENSO</span> on the Asian–Pacific–American region is possibly indirect and acts by inducing NDEAT. To separate corresponding influences of <span class="hlt">ENSO</span> and NDEAT, partial regression is utilized. It is noted that temperature variations in the East Asian–Western Pacific region are controlled mainly by NDEAT. In contrast, <span class="hlt">ENSO</span> demonstrates a weak direct relation to the temperature variation over the East Asian–Western Pacific region. This suggests that the influence of <span class="hlt">ENSO</span> on this region is indirect, through modulation of NDEAT. On the other hand, temperature variation over the tropical eastern Pacific is dominated by <span class="hlt">ENSO</span> forcing. Finally, temperature variation over the eastern North American–Western Pacific region is controlled by both <span class="hlt">ENSO</span> and NDEAT. Nevertheless, their influences on temperature and circulation over this region tend to offset each other. This implies that temperature variation is controlled by their relative strengths. PMID:27821838</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1094946-greenhouse-gases-changing-enso-precursors-western-north-pacific','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1094946-greenhouse-gases-changing-enso-precursors-western-north-pacific"><span>Are Greenhouse Gases Changing <span class="hlt">ENSO</span> Precursors in the Western North Pacific?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, S-Y; Heureux, Michelle L.; Yoon, Jin-Ho</p> <p></p> <p>Using multiple observational and modeling datasets, we document a strengthening relationship between boreal winter sea surface temperature anomalies (SSTA) in the western North Pacific (WNP) and the development of the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) one year later. The increased WNP-<span class="hlt">ENSO</span> association emerged in the mid 20th century and has grown through the present, reaching correlation coefficients as high as ~0.70 in recent decades. Fully coupled climate experiments with the Community Earth System Model (CESM) replicate the WNP-<span class="hlt">ENSO</span> association and indicate that greenhouse gases (GHG) are largely responsible for the observed increase. We speculate that shifts in the location and amplitudesmore » of positive SST trends in the subtropical-tropical western Pacific impacts the low-level circulation so that WNP variability is increasingly influencing the development of <span class="hlt">ENSO</span> one year later. A strengthened GHG-driven relationship between the WNP and <span class="hlt">ENSO</span> provides an example of how anthropogenic climate change can potentially improve the skill of intraseasonal-to-interannual climate prediction.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009NPGeo..16..453B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009NPGeo..16..453B"><span><span class="hlt">ENSO</span>'s non-stationary and non-Gaussian character: the role of climate shifts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boucharel, J.; Dewitte, B.; Garel, B.; Du Penhoat, Y.</p> <p>2009-07-01</p> <p>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of climate variability in the Pacific, having socio-economic impacts on surrounding regions. <span class="hlt">ENSO</span> exhibits significant modulation on decadal to inter-decadal time scales which is related to changes in its characteristics (onset, amplitude, frequency, propagation, and predictability). Some of these characteristics tend to be overlooked in <span class="hlt">ENSO</span> studies, such as its asymmetry (the number and amplitude of warm and cold events are not equal) and the deviation of its statistics from those of the Gaussian distribution. These properties could be related to the ability of the current generation of coupled models to predict <span class="hlt">ENSO</span> and its modulation. Here, <span class="hlt">ENSO</span>'s non-Gaussian nature and asymmetry are diagnosed from in situ data and a variety of models (from intermediate complexity models to full-physics coupled general circulation models (CGCMs)) using robust statistical tools initially designed for financial mathematics studies. In particular α-stable laws are used as theoretical background material to measure (and quantify) the non-Gaussian character of <span class="hlt">ENSO</span> time series and to estimate the skill of ``naïve'' statistical models in producing deviation from Gaussian laws and asymmetry. The former are based on non-stationary processes dominated by abrupt changes in mean state and empirical variance. It is shown that the α-stable character of <span class="hlt">ENSO</span> may result from the presence of climate shifts in the time series. Also, cool (warm) periods are associated with <span class="hlt">ENSO</span> statistics having a stronger (weaker) tendency towards Gaussianity and lower (greater) asymmetry. This supports the hypothesis of <span class="hlt">ENSO</span> being rectified by changes in mean state through nonlinear processes. The relationship between changes in mean state and nonlinearity (skewness) is further investigated both in the Zebiak and Cane (1987)'s model and the models of the Intergovernmental Panel for Climate Change (IPCC). Whereas there is a clear relationship in all</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12228724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12228724"><span><span class="hlt">ENSO</span> and cholera: a nonstationary link related to climate change?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodo, Xavier; Pascual, Mercedes; Fuchs, George; Faruque, A S G</p> <p>2002-10-01</p> <p>We present here quantitative evidence for an increased role of interannual climate variability on the temporal dynamics of an infectious disease. The evidence is based on time-series analyses of the relationship between El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) and cholera prevalence in Bangladesh (formerly Bengal) during two different time periods. A strong and consistent signature of <span class="hlt">ENSO</span> is apparent in the last two decades (1980-2001), while it is weaker and eventually uncorrelated during the first parts of the last century (1893-1920 and 1920-1940, respectively). Concomitant with these changes, the Southern Oscillation Index (SOI) undergoes shifts in its frequency spectrum. These changes include an intensification of the approximately 4-yr cycle during the recent interval as a response to the well documented Pacific basin regime shift of 1976. This change in remote <span class="hlt">ENSO</span> modulation alone can only partially serve to substantiate the differences observed in cholera. Regional or basin-wide changes possibly linked to global warming must be invoked that seem to facilitate <span class="hlt">ENSO</span> transmission. For the recent cholera series and during specific time intervals corresponding to local maxima in <span class="hlt">ENSO</span>, this climate phenomenon accounts for over 70% of disease variance. This strong association is discontinuous in time and can only be captured with a technique designed to isolate transient couplings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6073P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6073P"><span>Interhemispheric temperature difference as a predictor of boreal winter <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piskozub, Jacek; Gutowska, Dorota</p> <p>2013-04-01</p> <p>We use statistical analysis to show statistically significant relationship between the boreal winter MEI index of <span class="hlt">ENSO</span> and HadCRUT3 temperature difference between Northern and Southern hemispheres (NH - SH) during the preceding summer. Correlation values increase (in absolute terms) if the correlated time periods are increased from month to seasonal length. For example December and January (DJ) MEI values anticorrelate stronger with the preceding MJJA period than with any of the four months taken separately. We believe this is further evidence that the correlation is caused by a real physical process as increase of the averaging period tends to reduce statistical noise. The motivation for looking for such a relationship comes from review of literature on paleoclimatic <span class="hlt">ENSO</span> behavior. We have noticed that in many cases relatively cold NH coincided with "strong <span class="hlt">ENSO</span>" (frequent El Niños), for example the Ice Age periods and Little Ice Age. On the other hand periods of relatively warm NH (the Holocene climate optimum or Medieval Climate Anomaly) are coincident with frequent or even "permanent" La Niñas. This relationship suggest the influence of the position of Intertropical Convergence Zone (ITCZ) on the frequency of El Niños. The simplest physical mechanism of the relationship is that the positive (negative) NH-SH temperature difference causes a north (south) shift of ITCZ with a parallel shift of trade wind zones. The North-South orographic difference between the Panama Isthmus and the South America may cause stronger (weaker) trade winds in Eastern Tropical Pacific increasing (decreasing) the thermochemical tilt which, in turn, causes a more negative (positive) <span class="hlt">ENSO</span> values. Of course this may be only a first approximation of the real mechanism of this "teleconnection". The correlations we have found are not strong even if statistically significant. For example, the MJJA NH-SH temperature vs. DJ MEI correlation has r = -0.28 implying it explains only 8% of boreal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JCli...14..445T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JCli...14..445T"><span>A Linear Stochastic Dynamical Model of <span class="hlt">ENSO</span>. Part II: Analysis.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, C. J.; Battisti, D. S.</p> <p>2001-02-01</p> <p>In this study the behavior of a linear, intermediate model of <span class="hlt">ENSO</span> is examined under stochastic forcing. The model was developed in a companion paper (Part I) and is derived from the Zebiak-Cane <span class="hlt">ENSO</span> model. Four variants of the model are used whose stabilities range from slightly damped to moderately damped. Each model is run as a simulation while being perturbed by noise that is uncorrelated (white) in space and time. The statistics of the model output show the moderately damped models to be more realistic than the slightly damped models. The moderately damped models have power spectra that are quantitatively quite similar to observations, and a seasonal pattern of variance that is qualitatively similar to observations. All models produce <span class="hlt">ENSOs</span> that are phase locked to the annual cycle, and all display the `spring barrier' characteristic in their autocorrelation patterns, though in the models this `barrier' occurs during the summer and is less intense than in the observations (inclusion of nonlinear effects is shown to partially remedy this deficiency). The more realistic models also show a decadal variability in the lagged autocorrelation pattern that is qualitatively similar to observations.Analysis of the models shows that the greatest part of the variability comes from perturbations that project onto the first singular vector, which then grow rapidly into the <span class="hlt">ENSO</span> mode. Essentially, the model output represents many instances of the <span class="hlt">ENSO</span> mode, with random phase and amplitude, stimulated by the noise through the optimal transient growth of the singular vectors.The limit of predictability for each model is calculated and it is shown that the more realistic (moderately damped) models have worse potential predictability (9-15 months) than the deterministic chaotic models that have been studied widely in the literature. The predictability limits are strongly correlated with the stability of the models' <span class="hlt">ENSO</span> mode-the more highly damped models having much shorter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP13A1067T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP13A1067T"><span>Shifting patterns of <span class="hlt">ENSO</span> variability from a 492-year South Pacific coral core</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tangri, N.; Linsley, B. K.; Mucciarone, D.; Dunbar, R. B.</p> <p>2017-12-01</p> <p>Anticipating the impacts of <span class="hlt">ENSO</span> in a changing climate requires detailed reconstructions of changes in its timing, amplitude, and spatial pattern, as well as attempts to attribute those changes to external forcing or internal variability. A continuous coral δ18O record from American Samoa, in the tropical South Pacific, sheds light on almost five centuries of these changes. We find evidence of internally-driven 50-100 year cycles with broad peaks of high variability punctuated by short transitions of low variability. We see a long, slow trend towards more frequent <span class="hlt">ENSO</span> events, punctuated by sharp decreases in frequency; the 20th century in particular shows a strong trend towards higher-frequency <span class="hlt">ENSO</span>. Due to the unique location of American Samoa with respect to <span class="hlt">ENSO</span> sea surface temperature (SST) anomalies, we infer changes in the spatial pattern of <span class="hlt">ENSO</span>. American Samoa currently lies on the <span class="hlt">ENSO</span> 3.4 nodal line - the boomerang shape that separates waters warmed by El Niño from those that cool. Closer examination reveals that SST around American Samoa displays opposing responses to Eastern and Central Pacific <span class="hlt">ENSO</span> events. However, this has not always been the case; in the late 19th and early 20th century, SST responded similarly to both flavors of <span class="hlt">ENSO</span>. We interpret this to mean a geographic narrowing towards the equator of the eastern Pacific El Niño SST anomaly pattern in the first half of the 20th century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=depression+AND+teens&pg=5&id=EJ888878','ERIC'); return false;" href="https://eric.ed.gov/?q=depression+AND+teens&pg=5&id=EJ888878"><span>Psychometric Characteristics of the Teen Addiction Severity Index-Two (T-<span class="hlt">ASI</span>-2)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Brodey, Benjamin B.; McMullin, Darcy; Kaminer, Yifrah; Winters, Ken C.; Mosshart, Edward; Rosen, Craig S.; Brodey, Inger S.</p> <p>2008-01-01</p> <p>The Teen Addiction Severity Index-Two (T-<span class="hlt">ASI</span>-2) was developed as an extension of the T-<span class="hlt">ASI</span> to assess the severity of substance abuse and related problems among adolescents (N = 371) 12-19 years of age. The T-<span class="hlt">ASI</span>-2 consists of 18 domains that assess current use of alcohol, tobacco, marijuana, and other drugs, as well as mental health service…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=514929','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=514929"><span>T4 <span class="hlt">Asi</span>A blocks DNA recognition by remodeling σ70 region 4</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lambert, Lester J; Wei, Yufeng; Schirf, Virgil; Demeler, Borries; Werner, Milton H</p> <p>2004-01-01</p> <p>Bacteriophage T4 <span class="hlt">Asi</span>A is a versatile transcription factor capable of inhibiting host gene expression as an ‘anti-σ′ factor while simultaneously promoting gene-specific expression of T4 middle genes in conjunction with T4 MotA. To accomplish this task, <span class="hlt">Asi</span>A engages conserved region 4 of Eschericia coli σ70, blocking recognition of most host promoters by sequestering the DNA-binding surface at the <span class="hlt">Asi</span>A/σ70 interface. The three-dimensional structure of an <span class="hlt">Asi</span>A/region 4 complex reveals that the C-terminal α helix of region 4 is unstructured, while four other helices adopt a completely different conformation relative to the canonical structure of unbound region 4. That <span class="hlt">Asi</span>A induces, rather than merely stabilizes, this rearrangement can be realized by comparison to the homologous structures of region 4 solved in a variety of contexts, including the structure of Thermotoga maritima σA region 4 described herein. <span class="hlt">Asi</span>A simultaneously occupies the surface of region 4 that ordinarily contacts core RNA polymerase (RNAP), suggesting that an <span class="hlt">Asi</span>A-bound σ70 may also undergo conformational changes in the context of the RNAP holoenzyme. PMID:15257291</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS53A2009S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS53A2009S"><span>Asian Summer Monsoon Rainfall associated with <span class="hlt">ENSO</span> and its Predictability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shin, C. S.; Huang, B.; Zhu, J.; Marx, L.; Kinter, J. L.; Shukla, J.</p> <p>2015-12-01</p> <p>The leading modes of the Asian summer monsoon (ASM) rainfall variability and their seasonal predictability are investigated using the CFSv2 hindcasts initialized from multiple ocean analyses over the period of 1979-2008 and observation-based analyses. It is shown that the two leading empirical orthogonal function (EOF) modes of the observed ASM rainfall anomalies, which together account for about 34% of total variance, largely correspond to the ASM responses to the <span class="hlt">ENSO</span> influences during the summers of the developing and decaying years of a Pacific anomalous event, respectively. These two ASM modes are then designated as the contemporary and delayed <span class="hlt">ENSO</span> responses, respectively. It is demonstrated that the CFSv2 is capable of predicting these two dominant ASM modes up to the lead of 5 months. More importantly, the predictability of the ASM rainfall are much higher with respect to the delayed <span class="hlt">ENSO</span> mode than the contemporary one, with the predicted principal component time series of the former maintaining high correlation skill and small ensemble spread with all lead months whereas the latter shows significant degradation in both measures with lead-time. A composite analysis for the ASM rainfall anomalies of all warm <span class="hlt">ENSO</span> events in this period substantiates the finding that the ASM is more predictable following an <span class="hlt">ENSO</span> event. The enhanced predictability mainly comes from the evolution of the warm SST anomalies over the Indian Ocean in the spring of the <span class="hlt">ENSO</span> maturing phases and the persistence of the anomalous high sea surface pressure over the western Pacific in the subsequent summer, which the hindcasts are able to capture reasonably well. The results also show that the ensemble initialization with multiple ocean analyses improves the CFSv2's prediction skill of both <span class="hlt">ENSO</span> and ASM rainfall. In fact, the skills of the ensemble mean hindcasts initialized from the four different ocean analyses are always equivalent to the best ones initialized from any individual ocean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5336F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5336F"><span><span class="hlt">ENSO</span> in a warming world: interannual climate variability in the early Miocene Southern Hemisphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fox, Bethany; Wilson, Gary; Lee, Daphne</p> <p>2016-04-01</p> <p>The El Niño - Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant source of interannual variability in the modern-day climate system. <span class="hlt">ENSO</span> is a quasi-periodic cycle with a recurrence interval of 2-8 years. A major question in modern climatology is how <span class="hlt">ENSO</span> will respond to increased climatic warmth. <span class="hlt">ENSO</span>-like (2-8 year) cycles have been detected in many palaeoclimate records for the Holocene. However, the temporal resolution of pre-Quaternary palaeoclimate archives is generally too coarse to investigate <span class="hlt">ENSO</span>-scale variability. We present a 100-kyr record of <span class="hlt">ENSO</span>-like variability during the second half of the Oligocene/Miocene Mi-1 event, a period of increasing global temperatures and Antarctic deglaciation (~23.032-2.93 Ma). This record is drawn from an annually laminated lacustrine diatomite from southern New Zealand, a region strongly affected by <span class="hlt">ENSO</span> in the present day. The diatomite consists of seasonal alternations of light (diatom bloom) and dark (low diatom productivity) layers. Each light-dark couplet represents one year's sedimentation. Light-dark couplet thickness is characterised by <span class="hlt">ENSO</span>-scale variability. We use high-resolution (sub-annual) measurements of colour spectra to detect couplet thickness variability. Wavelet analysis indicates that absolute values are modulated by orbital cycles. However, when orbital effects are taken into account, <span class="hlt">ENSO</span>-like variability occurs throughout the entire depositional period, with no clear increase or reduction in relation to Antarctic deglaciation and increasing global warmth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013371','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013371"><span>The Response of Tropical Tropospheric Ozone to <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, L. D.; Ziemke, J. R.; Douglass, A. R.; Waugh, D. W.; Lang, C.; Rodriguez, J. M.; Nielsen, J. E.</p> <p>2011-01-01</p> <p>We have successfully reproduced the Ozone <span class="hlt">ENSO</span> Index (OEI) in the Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) forced by observed sea surface temperatures over a 25-year period. The vertical ozone response to <span class="hlt">ENSO</span> is consistent with changes in the Walker circulation. We derive the sensitivity of simulated ozone to <span class="hlt">ENSO</span> variations using linear regression analysis. The western Pacific and Indian Ocean region shows similar positive ozone sensitivities from the surface to the upper troposphere, in response to positive anomalies in the Nino 3.4 Index. The eastern and central Pacific region shows negative sensitivities with the largest sensitivity in the upper troposphere. This vertical response compares well with that derived from SHADOZ ozonesondes in each region. The OEI reveals a response of tropospheric ozone to circulation change that is nearly independent of changes in emissions and thus it is potentially useful in chemistry-climate model evaluation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H43I1338K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H43I1338K"><span>Integration of <span class="hlt">ENSO</span> Signal Power Through Hydrological Processes in the Little River Watershed</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keener, V. W.; Jones, J. W.; Bosch, D. D.; Cho, J.</p> <p>2011-12-01</p> <p>The relationship of the El-Nino/Southern Oscillation (<span class="hlt">ENSO</span>) to hydrology is typically discussed in terms of the ability to separate significantly different hydrologic variable responses versus the anomaly that has taken place. Most of the work relating <span class="hlt">ENSO</span> trends to proxy variables had been done on precipitation records until the mid 1990s, at which point increasing numbers of studies started to focus on <span class="hlt">ENSO</span> relationships with streamflow as well as other environmental variables. The signals in streamflow are typically complex, representing the integration of both climatic, landscape, and anthropological responses that are able to strengthen the inherent <span class="hlt">ENSO</span> signal in chaotic regional precipitation data. There is a need to identify climate non-stationarities related to <span class="hlt">ENSO</span> and their links to watershed-scale outcomes. For risk-management in particular, inter-annual modes of climate variability and their seasonal expression are of interest. In this study, we analyze 36 years of historical monthly streamflow data from the Little River Watershed (LWR), a coastal plain ecosystem in Georgia, in conjunction with wavelet spectral analysis and modeling via the Soil & Water Assessment Tool (SWAT). Using both spectral and physical models allows us to identify the mechanism by which the <span class="hlt">ENSO</span> signal power in surface and simulated groundwater flow is strengthened as compared to precipitation. The clear increase in the power of the inter-annual climate signal is demonstrated by shared patterns in water budget and exceedance curves, as well as in high <span class="hlt">ENSO</span> related energy in the 95% significant wavelet spectra for each variable and the NINO 3.4 index. In the LRW, the power of the <span class="hlt">ENSO</span> teleconnection is increased in both the observed and simulated stream flow through the mechanisms of groundwater flow and interflow, through confinement by a geological layer, the Hawthorn Formation. This non-intuitive relationship between <span class="hlt">ENSO</span> signal strength and streamflow could prove to be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180001922','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180001922"><span><span class="hlt">ENSO</span> Related Interannual Lightning Variability from the Full TRMM LIS Lightning Climatology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clark, Austin; Cecil, Daniel J.</p> <p>2018-01-01</p> <p>It has been shown that the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) contributes to inter-annual variability of lightning production in the tropics and subtropics more than any other atmospheric oscillation. This study further investigated how <span class="hlt">ENSO</span> phase affects lightning production in the tropics and subtropics. Using the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) and the Oceanic Nino Index (ONI) for <span class="hlt">ENSO</span> phase, lightning data were averaged into corresponding mean annual warm, cold, and neutral 'years' for analysis of the different phases. An examination of the regional sensitivities and preliminary analysis of three locations was conducted using model reanalysis data to determine the leading convective mechanisms in these areas and how they might respond to the <span class="hlt">ENSO</span> phases. These processes were then studied for inter-annual variance and subsequent correlation to <span class="hlt">ENSO</span> during the study period to best describe the observed lightning deviations from year to year at each location.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP33A2106L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP33A2106L"><span><span class="hlt">ENSO</span>-driven nutrient variability recorded by central equatorial Pacific corals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LaVigne, M.; Nurhati, I. S.; Cobb, K. M.; McGregor, H. V.; Sinclair, D. J.; Sherrell, R. M.</p> <p>2012-12-01</p> <p>Recent evidence for shifts in global ocean primary productivity suggests that surface ocean nutrient availability is a key link between global climate and ocean carbon cycling. Time-series records from satellite, in situ buoy sensors, and bottle sampling have documented the impact of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) on equatorial Pacific hydrography and broad changes in biogeochemistry since the late 1990's, however, data are sparse prior to this. Here we use a new paleoceanographic nutrient proxy, coral P/Ca, to explore the impact of <span class="hlt">ENSO</span> on nutrient availability in the central equatorial Pacific at higher-resolution than available from in situ nutrient data. Corals from Christmas (157°W 2°N) and Fanning (159°W 4°N) Islands recorded a well-documented decrease in equatorial upwelling as a ~40% decrease in P/Ca during the 1997-98 <span class="hlt">ENSO</span> cycle, validating the application of this proxy to Pacific Porites corals. We compare the biogeochemical shifts observed through the 1997-98 event with two pre-TOGA-TAO <span class="hlt">ENSO</span> cycles (1982-83 and 1986-87) reconstructed from a longer Christmas Island core. All three corals revealed ~30-40% P/Ca depletions during <span class="hlt">ENSO</span> warming as a result of decreased regional wind stress, thermocline depth, and equatorial upwelling velocity. However, at the termination of each El Niño event, surface nutrients did not return to pre-<span class="hlt">ENSO</span> levels for ~4-12 months after, SST as a result of increased biological draw down of surface nutrients. These records demonstrate the utility of high-resolution coral nutrient archives for understanding the impact of tropical Pacific climate on the nutrient and carbon cycling of this key region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A43F0339S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A43F0339S"><span>MJO influence on <span class="hlt">ENSO</span> effects in precipitation and temperature over South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimizu, M. H.; Bombardi, R. J.; Ambrizzi, T.</p> <p>2013-12-01</p> <p>Researches on the effects of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) over precipitation and temperature, such as drought, flood, and anomalous high or cold temperatures, have great importance because of the impact of <span class="hlt">ENSO</span> on the environment, society, and economy. Several studies have reported the influences of <span class="hlt">ENSO</span> over South American precipitation and temperature climatological patterns, such as drier than normal conditions over northeast Brazil during the warm phase (El Niño) and wetter than normal conditions over northeast Brazil in the cold phase (La Niña). However, some recent studies focusing on the Northern Hemisphere have indicated that the basic response of <span class="hlt">ENSO</span> is dependent on the phase of the Madden-Julian Oscillation (MJO). The MJO is characterized by the eastward propagation of the convection from Indian to Central Pacific Ocean and is related to variations in the position and intensity of the South Atlantic Convergence Zone (SACZ). The present work investigates the combined response of the phases of these two distinct phenomena, <span class="hlt">ENSO</span> and MJO, over South America. Our goal is to explore the relative importance of the MJO to precipitation and temperature anomalies during <span class="hlt">ENSO</span> events. MJO events were defined using the MJO index created by Jones and Carvalho (2012) based on empirical orthogonal functions analysis. <span class="hlt">ENSO</span> phases were defined according to the Oceanic Niño Index provided by the National Oceanic and Atmospheric Administration (NOAA). A composite analysis with each combination of the phases of <span class="hlt">ENSO</span> and MJO was performed to obtain the mean patterns of temperature and precipitation over South America for the months of November to March (austral summer). The results showed that the precipitation and temperature anomalies patterns observed during <span class="hlt">ENSO</span> events, without the concurrent occurrence of the MJO, can be strengthened or weakened during events where <span class="hlt">ENSO</span> and MJO occur simultaneously. Moreover, the effect on the anomalies patterns in these</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1372956-competing-influences-anthropogenic-warming-enso-plant-physiology-future-terrestrial-aridity','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1372956-competing-influences-anthropogenic-warming-enso-plant-physiology-future-terrestrial-aridity"><span>Competing Influences of Anthropogenic Warming, <span class="hlt">ENSO</span>, and Plant Physiology on Future Terrestrial Aridity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bonfils, Céline; Anderson, Gemma; Santer, Benjamin D.</p> <p></p> <p>The 2011–16 California drought illustrates that drought-prone areas do not always experience relief once a favorable phase of El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) returns. In the twenty-first century, such an expectation is unrealistic in regions where global warming induces an increase in terrestrial aridity larger than the changes in aridity driven by <span class="hlt">ENSO</span> variability. This premise is also flawed in areas where precipitation supply cannot offset the global warming–induced increase in evaporative demand. Here, atmosphere-only experiments are analyzed to identify land regions where aridity is currently sensitive to <span class="hlt">ENSO</span> and where projected future changes in mean aridity exceed the range causedmore » by <span class="hlt">ENSO</span> variability. Insights into the drivers of these changes in aridity are obtained using simulations with the incremental addition of three different factors to the current climate: ocean warming, vegetation response to elevated CO 2 levels, and intensified CO 2 radiative forcing. The effect of ocean warming overwhelms the range of <span class="hlt">ENSO</span>-driven temperature variability worldwide, increasing potential evapotranspiration (PET) in most <span class="hlt">ENSO</span>-sensitive regions. Additionally, about 39% of the regions currently sensitive to <span class="hlt">ENSO</span> will likely receive less precipitation in the future, independent of the <span class="hlt">ENSO</span> phase. Consequently aridity increases in 67%–72% of the <span class="hlt">ENSO</span>-sensitive area. When both radiative and physiological effects are considered, the area affected by arid conditions rises to 75%–79% when using PET-derived measures of aridity, but declines to 41% when an aridity indicator for total soil moisture is employed. This reduction mainly occurs because plant stomatal resistance increases under enhanced CO 2 concentrations, resulting in improved plant water-use efficiency, and hence reduced evapotranspiration and soil desiccation. Imposing CO 2-invariant stomatal resistance may overestimate future drying in PET-derived indices.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1372956-competing-influences-anthropogenic-warming-enso-plant-physiology-future-terrestrial-aridity','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1372956-competing-influences-anthropogenic-warming-enso-plant-physiology-future-terrestrial-aridity"><span>Competing Influences of Anthropogenic Warming, <span class="hlt">ENSO</span>, and Plant Physiology on Future Terrestrial Aridity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Bonfils, Céline; Anderson, Gemma; Santer, Benjamin D.; ...</p> <p>2017-07-27</p> <p>The 2011–16 California drought illustrates that drought-prone areas do not always experience relief once a favorable phase of El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) returns. In the twenty-first century, such an expectation is unrealistic in regions where global warming induces an increase in terrestrial aridity larger than the changes in aridity driven by <span class="hlt">ENSO</span> variability. This premise is also flawed in areas where precipitation supply cannot offset the global warming–induced increase in evaporative demand. Here, atmosphere-only experiments are analyzed to identify land regions where aridity is currently sensitive to <span class="hlt">ENSO</span> and where projected future changes in mean aridity exceed the range causedmore » by <span class="hlt">ENSO</span> variability. Insights into the drivers of these changes in aridity are obtained using simulations with the incremental addition of three different factors to the current climate: ocean warming, vegetation response to elevated CO 2 levels, and intensified CO 2 radiative forcing. The effect of ocean warming overwhelms the range of <span class="hlt">ENSO</span>-driven temperature variability worldwide, increasing potential evapotranspiration (PET) in most <span class="hlt">ENSO</span>-sensitive regions. Additionally, about 39% of the regions currently sensitive to <span class="hlt">ENSO</span> will likely receive less precipitation in the future, independent of the <span class="hlt">ENSO</span> phase. Consequently aridity increases in 67%–72% of the <span class="hlt">ENSO</span>-sensitive area. When both radiative and physiological effects are considered, the area affected by arid conditions rises to 75%–79% when using PET-derived measures of aridity, but declines to 41% when an aridity indicator for total soil moisture is employed. This reduction mainly occurs because plant stomatal resistance increases under enhanced CO 2 concentrations, resulting in improved plant water-use efficiency, and hence reduced evapotranspiration and soil desiccation. Imposing CO 2-invariant stomatal resistance may overestimate future drying in PET-derived indices.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2381G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2381G"><span>Decadal modulation of the relationship between intraseasonal tropical variability and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gushchina, Daria; Dewitte, Boris</p> <p>2018-05-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) amplitude is modulated at decadal timescales, which, over the last decades, has been related to the low-frequency changes in the frequency of occurrence of the two types of El Niño events, that is the Eastern Pacific (EP) and Central Pacific (CP) El Niños. Meanwhile <span class="hlt">ENSO</span> is tightly linked to the intraseasonal tropical variability (ITV) that is generally enhanced prior to El Niño development and can act as a trigger of the event. Here we revisit the ITV/<span class="hlt">ENSO</span> relationship taking into account changes in <span class="hlt">ENSO</span> properties over the last six decades. The focus is on two main components of ITV, the Madden-Julian Oscillation (MJO) and convectively coupled equatorial Rossby waves (ER). We show that the ITV/<span class="hlt">ENSO</span> relationship exhibits a decadal modulation that is not related in a straight-forward manner to the change in occurrence of El Niño types and Pacific decadal modes. While enhanced MJO activity associated to EP El Niño development mostly took place over the period 1985-2000, the ER activity is enhanced prior to El Niño development over the whole period with a tendency to relate more to CP El Niño than to EP El Niño. In particular the relationship between ER activity and <span class="hlt">ENSO</span> was particularly strong for the period 2000-2015, which results in a significant positive long-term trend of the predictive value of ER activity. The statistics of the MJO and ER activity is consistent with the hypothesis that they can be considered a state-dependent noise for <span class="hlt">ENSO</span> linked to distinct lower frequency climate modes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1816170W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1816170W"><span>Indo-Pacific <span class="hlt">ENSO</span> modes in a double-basin Zebiak-Cane model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieners, Claudia; de Ruijter, Will; Dijkstra, Henk</p> <p>2016-04-01</p> <p>We study Indo-Pacific interactions on <span class="hlt">ENSO</span> timescales in a double-basin version of the Zebiak-Cane <span class="hlt">ENSO</span> model, employing both time integrations and bifurcation analysis (continuation methods). The model contains two oceans (the Indian and Pacific Ocean) separated by a meridional wall. Interaction between the basins is possible via the atmosphere overlaying both basins. We focus on the effect of the Indian Ocean (both its mean state and its variability) on <span class="hlt">ENSO</span> stability. In addition, inspired by analysis of observational data (Wieners et al, Coherent tropical Indo-Pacific interannual climate variability, in review), we investigate the effect of state-dependent atmospheric noise. Preliminary results include the following: 1) The background state of the Indian Ocean stabilises the Pacific <span class="hlt">ENSO</span> (i.e. the Hopf bifurcation is shifted to higher values of the SST-atmosphere coupling), 2) the West Pacific cooling (warming) co-occurring with El Niño (La Niña) is essential to simulate the phase relations between Pacific and Indian SST anomalies, 3) a non-linear atmosphere is needed to simulate the effect of the Indian Ocean variability onto the Pacific <span class="hlt">ENSO</span> that is suggested by observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.1429C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.1429C"><span>Indian Ocean and Indian summer monsoon: relationships without <span class="hlt">ENSO</span> in ocean-atmosphere coupled simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crétat, Julien; Terray, Pascal; Masson, Sébastien; Sooraj, K. P.; Roxy, Mathew Koll</p> <p>2017-08-01</p> <p>The relationship between the Indian Ocean and the Indian summer monsoon (ISM) and their respective influence over the Indo-Western North Pacific (WNP) region are examined in the absence of El Niño Southern Oscillation (<span class="hlt">ENSO</span>) in two partially decoupled global experiments. <span class="hlt">ENSO</span> is removed by nudging the tropical Pacific simulated sea surface temperature (SST) toward SST climatology from either observations or a fully coupled control run. The control reasonably captures the observed relationships between <span class="hlt">ENSO</span>, ISM and the Indian Ocean Dipole (IOD). Despite weaker amplitude, IODs do exist in the absence of <span class="hlt">ENSO</span> and are triggered by a boreal spring ocean-atmosphere coupled mode over the South-East Indian Ocean similar to that found in the presence of <span class="hlt">ENSO</span>. These pure IODs significantly affect the tropical Indian Ocean throughout boreal summer, inducing a significant modulation of both the local Walker and Hadley cells. This meridional circulation is masked in the presence of <span class="hlt">ENSO</span>. However, these pure IODs do not significantly influence the Indian subcontinent rainfall despite overestimated SST variability in the eastern equatorial Indian Ocean compared to observations. On the other hand, they promote a late summer cross-equatorial quadrupole rainfall pattern linking the tropical Indian Ocean with the WNP, inducing important zonal shifts of the Walker circulation despite the absence of <span class="hlt">ENSO</span>. Surprisingly, the interannual ISM rainfall variability is barely modified and the Indian Ocean does not force the monsoon circulation when <span class="hlt">ENSO</span> is removed. On the contrary, the monsoon circulation significantly forces the Arabian Sea and Bay of Bengal SSTs, while its connection with the western tropical Indian Ocean is clearly driven by <span class="hlt">ENSO</span> in our numerical framework. Convection and diabatic heating associated with above-normal ISM induce a strong response over the WNP, even in the absence of <span class="hlt">ENSO</span>, favoring moisture convergence over India.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=130557','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=130557"><span><span class="hlt">ENSO</span> and cholera: A nonstationary link related to climate change?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rodó, Xavier; Pascual, Mercedes; Fuchs, George; Faruque, A. S. G.</p> <p>2002-01-01</p> <p>We present here quantitative evidence for an increased role of interannual climate variability on the temporal dynamics of an infectious disease. The evidence is based on time-series analyses of the relationship between El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) and cholera prevalence in Bangladesh (formerly Bengal) during two different time periods. A strong and consistent signature of <span class="hlt">ENSO</span> is apparent in the last two decades (1980–2001), while it is weaker and eventually uncorrelated during the first parts of the last century (1893–1920 and 1920–1940, respectively). Concomitant with these changes, the Southern Oscillation Index (SOI) undergoes shifts in its frequency spectrum. These changes include an intensification of the approximately 4-yr cycle during the recent interval as a response to the well documented Pacific basin regime shift of 1976. This change in remote <span class="hlt">ENSO</span> modulation alone can only partially serve to substantiate the differences observed in cholera. Regional or basin-wide changes possibly linked to global warming must be invoked that seem to facilitate <span class="hlt">ENSO</span> transmission. For the recent cholera series and during specific time intervals corresponding to local maxima in <span class="hlt">ENSO</span>, this climate phenomenon accounts for over 70% of disease variance. This strong association is discontinuous in time and can only be captured with a technique designed to isolate transient couplings. PMID:12228724</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SGeo...39....1N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SGeo...39....1N"><span>Global Terrestrial Water Storage Changes and Connections to <span class="hlt">ENSO</span> Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ni, Shengnan; Chen, Jianli; Wilson, Clark R.; Li, Jin; Hu, Xiaogong; Fu, Rong</p> <p>2018-01-01</p> <p>Improved data quality of extended record of the Gravity Recovery and Climate Experiment (GRACE) satellite gravity solutions enables better understanding of terrestrial water storage (TWS) variations. Connections of TWS and climate change are critical to investigate regional and global water cycles. In this study, we provide a comprehensive analysis of global connections between interannual TWS changes and El Niño Southern Oscillation (<span class="hlt">ENSO</span>) events, using multiple sources of data, including GRACE measurements, land surface model (LSM) predictions and precipitation observations. We use cross-correlation and coherence spectrum analysis to examine global connections between interannual TWS changes and the Niño 3.4 index, and select four river basins (Amazon, Orinoco, Colorado, and Lena) for more detailed analysis. The results indicate that interannual TWS changes are strongly correlated with <span class="hlt">ENSO</span> over much of the globe, with maximum cross-correlation coefficients up to 0.70, well above the 95% significance level ( 0.29) derived by the Monte Carlo experiments. The strongest correlations are found in tropical and subtropical regions, especially in the Amazon, Orinoco, and La Plata basins. While both GRACE and LSM TWS estimates show reasonably good correlations with <span class="hlt">ENSO</span> and generally consistent spatial correlation patterns, notably higher correlations are found between GRACE TWS and <span class="hlt">ENSO</span>. The existence of significant correlations in middle-high latitudes shows the large-scale impact of <span class="hlt">ENSO</span> on the global water cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC31D1206W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC31D1206W"><span>Mapping <span class="hlt">ENSO</span>: Precipitation for the U.S. Affiliated Pacific Islands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, E.; Price, J.; Kruk, M. C.; Luchetti, N.; Marra, J. J.</p> <p>2015-12-01</p> <p>The United States Affiliated Pacific Islands (USAPI) are highly susceptible to extreme precipitation events such as drought and flooding, which directly affect their freshwater availability. Precipitation distribution differs by sub-region, and is predominantly influenced by phases of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>). Forecasters currently rely on <span class="hlt">ENSO</span> climatologies from sparse in situ station data to inform their precipitation outlooks. This project provided an updated <span class="hlt">ENSO</span>-based climatology of long-term precipitation patterns for each USAPI Exclusive Economic Zone (EEZ) using the NOAA PERSIANN Climate Data Record (CDR). This data provided a 30-year record (1984-2015) of daily precipitation at 0.25° resolution, which was used to calculate monthly, seasonal, and yearly precipitation. Results indicated that while the PERSIANN precipitation accurately described the monthly, seasonal, and annual trends, it under-predicted the precipitation on the islands. Additionally, maps showing percent departure from normal (30 year average) were made for each three month season based on the Oceanic Niño Index (ONI) for five <span class="hlt">ENSO</span> phases (moderate-strong El Niño and La Niña, weak El Niño and La Niña, and neutral). Local weather service offices plan on using these results and maps to better understand how the different <span class="hlt">ENSO</span> phases influence precipitation patterns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS34A..08C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS34A..08C"><span>Biological consequences of <span class="hlt">ENSO</span>: What have we learned recently?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chavez, F.; Messié, M.</p> <p>2013-12-01</p> <p>A comprehensive theory regarding the biological response to El Niño was developed from observations during the 1982-83 event. The theory has withstood the test of time but additional information from remote sensing and growing in situ databases has allowed for a more comprehensive evaluation of the biological consequences of the full <span class="hlt">ENSO</span> cycle on global scales and in relation to other climatic variability and change. Here we review the major developments over the past few decades that include a greater appreciation for the cool or La Niña phase and the relation of <span class="hlt">ENSO</span> to other climatic variability including the Pacific Decadal Oscillation and the North Pacific Gyre Oscillation. The use of <span class="hlt">ENSO</span> as an analog for biological consequences of a warmer world is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A42E..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A42E..05K"><span>Inter-model Diversity of <span class="hlt">ENSO</span> simulation and its relation to basic states</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kug, J. S.; Ham, Y. G.</p> <p>2016-12-01</p> <p>In this study, a new methodology is developed to improve the climate simulation of state-of-the-art coupledglobal climate models (GCMs), by a postprocessing based on the intermodel diversity. Based on the closeconnection between the interannual variability and climatological states, the distinctive relation between theintermodel diversity of the interannual variability and that of the basic state is found. Based on this relation,the simulated interannual variabilities can be improved, by correcting their climatological bias. To test thismethodology, the dominant intermodel difference in precipitation responses during El Niño-SouthernOscillation (<span class="hlt">ENSO</span>) is investigated, and its relationship with climatological state. It is found that the dominantintermodel diversity of the <span class="hlt">ENSO</span> precipitation in phase 5 of the Coupled Model Intercomparison Project(CMIP5) is associated with the zonal shift of the positive precipitation center during El Niño. This dominantintermodel difference is significantly correlated with the basic states. The models with wetter (dryer) climatologythan the climatology of the multimodel ensemble (MME) over the central Pacific tend to shift positive<span class="hlt">ENSO</span> precipitation anomalies to the east (west). Based on the model's systematic errors in atmospheric<span class="hlt">ENSO</span> response and bias, the models with better climatological state tend to simulate more realistic atmospheric<span class="hlt">ENSO</span> responses.Therefore, the statistical method to correct the <span class="hlt">ENSO</span> response mostly improves the <span class="hlt">ENSO</span> response. Afterthe statistical correction, simulating quality of theMMEENSO precipitation is distinctively improved. Theseresults provide a possibility that the present methodology can be also applied to improving climate projectionand seasonal climate prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000085545','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000085545"><span>Dynamics of Monsoon-Induced Biennial Variability in <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Kyu-Myong; Lau, K.-M.; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>The mechanism of the quasi-biennial tendency in El Nino Southern Oscillation (<span class="hlt">ENSO</span>)-monsoon coupled system is investigated using an intermediate coupled model. The monsoon wind forcing is prescribed as a function of Sea Surface Temperature (SST) anomalies based on the relationship between zonal wind anomalies over the western Pacific to sea level change in the equatorial eastern Pacific. The key mechanism of quasi-biennial tendency in El Nino evolution is found to be in the strong coupling of <span class="hlt">ENSO</span> to monsoon wind forcing over the western Pacific. Strong boreal summer monsoon wind forcing, which lags the maximum SST anomaly in the equatorial eastern Pacific approximately 6 months, tends to generate Kelvin waves of the opposite sign to anomalies in the eastern Pacific and initiates the turnabout in the eastern Pacific. Boreal winter monsoon forcing, which has zero lag with maximum SST in the equatorial eastern Pacific, tends to damp the <span class="hlt">ENSO</span> oscillations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.7438Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.7438Y"><span>The role of South Pacific atmospheric variability in the development of different types of <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>You, Yujia; Furtado, Jason C.</p> <p>2017-07-01</p> <p>Recent advances in tropical Pacific climate variability have focused on understanding the development of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) events, specifically the types or "flavors" of <span class="hlt">ENSO</span> (i.e., central versus eastern Pacific events). While precursors to <span class="hlt">ENSO</span> events exist, distinguishing the particular flavor of the expected <span class="hlt">ENSO</span> event remains unresolved. This study offers a new look at <span class="hlt">ENSO</span> predictability using South Pacific atmospheric variability during austral winter as an indicator. The positive phase of the leading mode of South Pacific sea level pressure variability, which we term the South Pacific Oscillation (SPO), exhibits a meridional dipole with with a(n) (anti)cyclonic anomaly dominating the subtropics (extratropics/high latitudes). Once energized, the cyclonic anomalies in the subtropical node of the SPO weaken the southeasterly trade winds and promote the charging of the eastern equatorial Pacific Ocean, giving rise to eastern Pacific <span class="hlt">ENSO</span> events. Indeed, the type of <span class="hlt">ENSO</span> event can be determined accurately using only the magnitude and phase of the SPO during austral winter as a predictor (17 out of 23 cases). The SPO may also play a role in explaining the asymmetry of warm and cold events. Collectively, our findings present a new perspective on <span class="hlt">ENSO</span>-South Pacific interactions that can advance overall understanding of the <span class="hlt">ENSO</span> system and enhance its predictability across multiple timescales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27787628','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27787628"><span><span class="hlt">ENSO</span> and PDO-related climate variability impacts on Midwestern United States crop yields.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Henson, Chasity; Market, Patrick; Lupo, Anthony; Guinan, Patrick</p> <p>2017-05-01</p> <p>An analysis of crop yields for the state of Missouri was completed to determine if an interannual or multidecadal variability existed as a result of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and the Pacific Decadal Oscillation (PDO). Corn and soybean yields were recorded in kilograms per hectare for each of the six climate regions of Missouri. An analysis using the Mokhov "method of cycles" demonstrated interannual, interdecadal, and multidecadal variations in crop yields. Cross-spectral analysis was used to determine which region was most impacted by <span class="hlt">ENSO</span> and PDO influenced seasonal (April-September) temperature and precipitation. Interannual (multidecadal) variations found in the spectral analysis represent a relationship to <span class="hlt">ENSO</span> (PDO) phase, while interdecadal variations represent a possible interaction between <span class="hlt">ENSO</span> and PDO. Average crop yields were then calculated for each combination of <span class="hlt">ENSO</span> and PDO phase, displaying a pronounced increase in corn and soybean yields when <span class="hlt">ENSO</span> is warm and PDO is positive. Climate regions 1, 2, 4, and 6 displayed significant differences (p value of 0.10 or less) in yields between El Niño and La Niña years, representing 55-70 % of Missouri soybean and corn productivity, respectively. Final results give the opportunity to produce seasonal predictions of corn and soybean yields, specific to each climate region in Missouri, based on the combination of <span class="hlt">ENSO</span> and PDO phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMPP51A0302E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMPP51A0302E"><span>Tracking <span class="hlt">ENSO</span> with tropical trees: Progress in stable isotope dendroclimatology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Evans, M. N.; Poussart, P. F.; Saleska, S. R.; Schrag, D. P.</p> <p>2002-12-01</p> <p>The terrestrial tropics remain an important gap in the growing proxy network used to characterize past <span class="hlt">ENSO</span> behavior. Here we describe a strategy for development of proxy estimates of paleo-<span class="hlt">ENSO</span>, via proxy rainfall estimates derived from stable isotope (δ18O) measurements made on tropical trees. The approach applies a new model of oxygen isotopic composition of alpha-cellulose (Roden et al., 2000), a rapid method for cellulose extraction from raw wood (Brendel et al., 2000), and continuous flow isotope ratio mass spectrometry (Brand, 1996) to develop proxy chronological, rainfall and growth rate estimates from tropical trees, even those lacking annual rings. The promise and pitfalls of the approach are illustrated in pilot datasets from the US, Costa Rica, Brazil, and Peru, which show isotopic cycles of 4-6 per mil, and interannual anomalies of up to 8 per mil. Together with the mature <span class="hlt">ENSO</span> proxies (corals, extratropical tree-rings, varved sediments, and ice cores), replicated and well-dated stable isotope chronologies from tropical trees may eventually improve our understanding of <span class="hlt">ENSO</span> history over the past several hundred years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18....8S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18....8S"><span>Dynamics and spatial structure of <span class="hlt">ENSO</span> from re-analyses versus CMIP5 models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serykh, Ilya; Sonechkin, Dmitry</p> <p>2016-04-01</p> <p>Basing on a mathematical idea about the so-called strange nonchaotic attractor (SNA) in the quasi-periodically forced dynamical systems, the currently available re-analyses data are considered. It is found that the El Niño - Southern Oscillation (<span class="hlt">ENSO</span>) is driven not only by the seasonal heating, but also by three more external periodicities (incommensurate to the annual period) associated with the ~18.6-year lunar-solar nutation of the Earth rotation axis, ~11-year sunspot activity cycle and the ~14-month Chandler wobble in the Earth's pole motion. Because of the incommensurability of their periods all four forces affect the system in inappropriate time moments. As a result, the <span class="hlt">ENSO</span> time series look to be very complex (strange in mathematical terms) but nonchaotic. The power spectra of <span class="hlt">ENSO</span> indices reveal numerous peaks located at the periods that are multiples of the above periodicities as well as at their sub- and super-harmonic. In spite of the above <span class="hlt">ENSO</span> complexity, a mutual order seems to be inherent to the <span class="hlt">ENSO</span> time series and their spectra. This order reveals itself in the existence of a scaling of the power spectrum peaks and respective rhythms in the <span class="hlt">ENSO</span> dynamics that look like the power spectrum and dynamics of the SNA. It means there are no limits to forecast <span class="hlt">ENSO</span>, in principle. In practice, it opens a possibility to forecast <span class="hlt">ENSO</span> for several years ahead. Global spatial structures of anomalies during El Niño and power spectra of <span class="hlt">ENSO</span> indices from re-analyses are compared with the respective output quantities in the CMIP5 climate models (the Historical experiment). It is found that the models reproduce global spatial structures of the near surface temperature and sea level pressure anomalies during El Niño very similar to these fields in the re-analyses considered. But the power spectra of the <span class="hlt">ENSO</span> indices from the CMIP5 models show no peaks at the same periods as the re-analyses power spectra. We suppose that it is possible to improve modeled</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6386D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6386D"><span>Sensitivity of <span class="hlt">ENSO</span> teleconnections to a warming background state.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drouard, Marie; Cassou, Christophe</p> <p>2016-04-01</p> <p>The sensitivity of <span class="hlt">ENSO</span> teleconnections to the background state is investigated using two ensembles of coupled model experiments, one representative of the pre-industrial climate and the other one expected of the end of the 21st century based on the high emission RCP85 scenario. A 30-year period of representative <span class="hlt">ENSO</span> events bearing resemblance to observed ones is a priori selected from a 850-year pre-industrial simulation of the CNRM-CM5 model. Following the so-called pacemaker protocol, new coupled experiments are carried with the model SST being restored in the eastern tropical Pacific towards the selected anomalies, the rest of the globe being fully coupled. In the first set of experiments, the anomalous restoring is applied on top of pre-industrial mean ocean state and in the second, on top of RCP85 mean state. Two sets of 10-member of 30-year long integrations are then generated. By construction, they share the exact same <span class="hlt">ENSO</span> and thus make it possible to strictly isolate the dependence of the <span class="hlt">ENSO</span> teleconnections to a warmer background state. Results confirm the eastward shift of the <span class="hlt">ENSO</span>-induced deepening Aleutian low as documented in the literature for the winter season. They also show changes in the wintertime teleconnection over the North Atlantic. Several diagnostic tools (such as E-vectors) are used to investigate the dynamics of the teleconnection between the tropical Pacific, the North Pacific and dowstream towards the North Atlantic along the jet wave guide. A more indirect route based on the change in the Walker cell and associated signals in the tropical Atlantic leading to the excitation of forced Rossby wave is also analysed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A34E..06Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A34E..06Y"><span>The increasing control of the Atlantic Ocean on <span class="hlt">ENSO</span> after the early 1990s</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, J. Y.; Paek, H.; Wang, L.; Lyu, K.</p> <p>2016-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is the most powerful interannual variability in Earth's climate system. Previous studies have emphasized processes within the tropical Pacific or Indian Oceans for the generation of <span class="hlt">ENSO</span>. Recent studies have increasingly suggested that the Atlantic Ocean may play an active role in forcing <span class="hlt">ENSO</span> variability. In this talk, we will present evidence from observational analyses and modeling experiments to show that the Atlantic Ocean became more capable of influencing <span class="hlt">ENSO</span> properties after the Atlantic Multidecadal Oscillation (AMO) changed to its positive phase in the early-1990s. A wave source mechanism is proposed to explain how the positive phase of the AMO can intensify the North Pacific Subtropical High (NPSH) to change the <span class="hlt">ENSO</span> from the Eastern Pacific (EP) type to the Central Pacific (CP) type. A sequence of processes are identified to suggest that the AMO can displace the Pacific Walker circulation, induce a wave source in the tropical central Pacific, and excite a barotropic wave train toward higher-latitudes to enhance the NPSH, which then triggers subtropical Pacific atmospheric forcing and atmosphere-ocean coupling to increase the occurrence of the CP <span class="hlt">ENSO</span>. An Atlantic capacitor mechanism is also proposed to explain how the positive phase of the AMO can intensify the quasi-biennial (QB) component of <span class="hlt">ENSO</span> resulting in a more frequent occurrence of <span class="hlt">ENSO</span> events. We will show that the capacitor mechanism works only after the AMO warmed up the Atlantic sea surface temperatures after the early-1990s. The increased feedback from the Atlantic to the Pacific has enabled the Atlantic capacitor mechanism to intensify the biennial variability in the Pacific during the past two decades. Our suggestion is very different from the previous prevailing views that have emphasized the Indo-Pacific Oceans as the pacemaker for the biennial variability in <span class="hlt">ENSO</span>. The increasing control of the Atlantic has enabled the CP <span class="hlt">ENSO</span> dynamics to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP43D..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP43D..05K"><span>Using multi-resolution proxies to assess <span class="hlt">ENSO</span> impacts on the mean state of the tropical Pacific.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karamperidou, C.; Conroy, J. L.</p> <p>2016-12-01</p> <p>Observations and model simulations indicate that the relationship between <span class="hlt">ENSO</span> and the mean state of the tropical Pacific is a two-way interaction. On one hand, a strong zonal SST gradient (dSST) in the Pacific (colder cold tongue) increases the potential intensity of upcoming <span class="hlt">ENSO</span> events and may lead to increased <span class="hlt">ENSO</span> variance. On the other hand, in a period of increased <span class="hlt">ENSO</span> activity, large events can warm the cold tongue at decadal scales via residual heating, and thus lead to reduced zonal SST gradient (<span class="hlt">ENSO</span> rectification mechanism). The short length of the observational record hinders our ability to confidently evaluate which mechanism dominates in each period, and whether it is sensitive to external climate forcing. This question is effectively a question of interaction between two timescales: interannual and decadal. Paleoclimate proxies of different resolutions can help elucidate this question, since they can be independent records of variability in these separate timescales. Here, we use coral proxies of <span class="hlt">ENSO</span> variability from across the Pacific and multi-proxy records of dSST at longer timescales. Proxies, models, and observations indicate that in periods of increased <span class="hlt">ENSO</span> activity, dSST is negatively correlated with <span class="hlt">ENSO</span> variance at decadal timescales, indicating that strong <span class="hlt">ENSO</span> events may affect the decadal mean state via warming the cold tongue. Using climate model simulations we attribute this effect to residual nonlinear dynamical heating, thus supporting the <span class="hlt">ENSO</span> rectification mechanism. On the contrary, in periods without strong events, <span class="hlt">ENSO</span> variance and dSST are positively correlated, which indicates that the primary mechanism at work is the effect of the mean state on <span class="hlt">ENSO</span>. Our analysis also quantitatively identifies the regions where paleoclimate proxies are needed in order to reduce the existing uncertainties in <span class="hlt">ENSO</span>-mean state interactions. Hence, this study is a synthesis of observations, model simulations and paleoclimate proxy evidence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC32B..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC32B..03K"><span>Mean-state SST Response to global warming caused by the <span class="hlt">ENSO</span> Nonlinearity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohyama, T.; Hartmann, D. L.</p> <p>2017-12-01</p> <p>The majority of the models that participated in the Coupled Model Intercomparison Project phase 5 (CMIP5) exhibit El Niño-like trends under global warming. GFDL-ESM2M, however, is an exception that exhibits a La Niña-like response with strengthened trade winds. Our previous studies have shown that this La Niña-like trend could be a physically consistent warming response, and we proposed the Nonlinear <span class="hlt">ENSO</span> Warming Suppression (NEWS) mechanism to explain this La Niña-like response to global warming. The most important necessary condition of NEWS is the <span class="hlt">ENSO</span> skewness (El Niños are stronger than La Niñas). Most CMIP5 models do not reproduce the observed <span class="hlt">ENSO</span> skewness, while GFDL-ESM2M exhibits the realistic <span class="hlt">ENSO</span> skewness, which suggests that, despite being in the minority, the La Niña-like trend of GFDL-ESM2M could be a plausible equatorial Pacific response to warming. In this study, we introduce another interesting outlier, MIROC5, which reproduces the observed skewness, yet exhibits an El Niño-like response. By decomposing the source of the <span class="hlt">ENSO</span> nonlinearity into the following three components: "SST anomalies modulate winds", "winds excite oceanic waves", and "oceanic waves modulate the subsurface temperature", we show that the large inter-model spread of the third component appears to explain the most important cause of the poor reproducibility of the <span class="hlt">ENSO</span> nonlinearity in CMIP5 models. It is concluded that the change in the response of subsurface temperature to oceanic waves is the primary explanation for the different warming response of GFDL-ESM2M and MIROC5. Our analyses suggest that the difference of the warming response are caused by difference in the climatological thermal stratification. This study may shed new light on the fundamental question of why observed <span class="hlt">ENSO</span> has a strong skewness and on the implications of this skewed <span class="hlt">ENSO</span> for the mean-state sea surface temperature response to global warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021800','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021800"><span><span class="hlt">ENSO</span> and hydrologic extremes in the western United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cayan, D.R.; Redmond, K.T.; Riddle, L.G.</p> <p>1999-01-01</p> <p>Frequency distributions of daily precipitation in winter and daily stream flow from late winter to early summer, at several hundred sites in the western United States, exhibit strong and systematic responses to the two phases of <span class="hlt">ENSO</span>. Most of the stream flows considered are driven by snowmelt. The Southern Oscillation index (SOI) is used as the <span class="hlt">ENSO</span> phase indicator. Both modest (median) and larger (90th percentile) events were considered. In years with negative SOI values (El Nino), days with high daily precipitation and stream flow are more frequent than average over the Southwest and less frequent over the Northwest. During years with positive SOI values (La Nina), a nearly opposite pattern is seen. A more pronounced increase is seen in the number of days exceeding climatological 90th percentile values than in the number exceeding climatological 50th percentile values, for both precipitation and stream flow. Stream flow responses to <span class="hlt">ENSO</span> extremes are accentuated over precipitation responses. Evidence suggests that the mechanism for this amplification involves <span class="hlt">ENSO</span>-phase differences in the persistence and duration of wet episodes, affecting the efficiency of the process by which precipitation is converted to runoff. The SOI leads the precipitation events by several months, and hydrologic lags (mostly through snowmelt) dealy the stream flow response by several more months. The combined 6-12 month predictive aspect of this relationship should be of significant benefit in responding to flood (or drought) risk and in improving overall water management in the western states.Frequency distributions of daily precipitation in winter and daily stream flow from late winter to early summer, at several hundred sites in the western United States, exhibit strong and systematic responses to the two phases of <span class="hlt">ENSO</span>. Most of the stream flows considered are driven by snowmelt. The Southern Oscillation index (SOI) is used as the <span class="hlt">ENSO</span> phase indicator. Both modest (median) and larger</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6969C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6969C"><span>Coupling between strong warm <span class="hlt">ENSO</span> events and the phase of the stratospheric QBO.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Christiansen, Bo</p> <p>2017-04-01</p> <p>Although there in general are no significant long-term correlations between the QBO and the <span class="hlt">ENSO</span> in observations we find that the QBO and the <span class="hlt">ENSO</span> were aligned in the 3 to 4 years after the three strong warm <span class="hlt">ENSO</span> events in 1982, 1997, and 2015. We study this possible connection between the QBO and the <span class="hlt">ENSO</span> with a new version of the EC-Earth model which includes non-orographic gravity waves and a well modeled QBO. We analyze the modeled QBO in ensembles consisting of 10 AMIP-type experiments with climatological SSTs and 10 experiments with observed daily SSTs. The model experiments cover the period 1982-2013. For the <span class="hlt">ENSO</span> we use the multivariate index (MEI). As expected the coherence is strong and statistically significant in the equatorial troposphere in the ensemble with observed SSTs. Here the coherence is a measure of the alignment of the ensemble members. In the ensemble with observed SSTs we find a strong and significant alignment of the ensemble members in the equatorial stratospheric winds in the 2 to 4 years after the strong <span class="hlt">ENSO</span> event in 1997. This alignment also includes the observed QBO. No such alignment is found in the ensemble with climatological SSTs. These results indicate that strong warm <span class="hlt">ENSO</span> events can directly influence the phase of the QBO. An open and maybe related question is what caused the anomalous QBO in 2016. This behaviour, which is unprecedented in the 50-60 years with data, has been described as a hiccup or a death-spiral. At least it is clear that in the last 18 months the QBO has been stuck in the same corner of the phase-space spanned by its two leading principal components. The possible connection to the <span class="hlt">ENSO</span> will be investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.442...61C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.442...61C"><span>A high-resolution speleothem record of western equatorial Pacific rainfall: Implications for Holocene <span class="hlt">ENSO</span> evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Sang; Hoffmann, Sharon S.; Lund, David C.; Cobb, Kim M.; Emile-Geay, Julien; Adkins, Jess F.</p> <p>2016-05-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is the primary driver of interannual climate variability in the tropics and subtropics. Despite substantial progress in understanding ocean-atmosphere feedbacks that drive <span class="hlt">ENSO</span> today, relatively little is known about its behavior on centennial and longer timescales. Paleoclimate records from lakes, corals, molluscs and deep-sea sediments generally suggest that <span class="hlt">ENSO</span> variability was weaker during the mid-Holocene (4-6 kyr BP) than the late Holocene (0-4 kyr BP). However, discrepancies amongst the records preclude a clear timeline of Holocene <span class="hlt">ENSO</span> evolution and therefore the attribution of <span class="hlt">ENSO</span> variability to specific climate forcing mechanisms. Here we present δ18 O results from a U-Th dated speleothem in Malaysian Borneo sampled at sub-annual resolution. The δ18 O of Borneo rainfall is a robust proxy of regional convective intensity and precipitation amount, both of which are directly influenced by <span class="hlt">ENSO</span> activity. Our estimates of stalagmite δ18 O variance at <span class="hlt">ENSO</span> periods (2-7 yr) show a significant reduction in interannual variability during the mid-Holocene (3240-3380 and 5160-5230 yr BP) relative to both the late Holocene (2390-2590 yr BP) and early Holocene (6590-6730 yr BP). The Borneo results are therefore inconsistent with lacustrine records of <span class="hlt">ENSO</span> from the eastern equatorial Pacific that show little or no <span class="hlt">ENSO</span> variance during the early Holocene. Instead, our results support coral, mollusc and foraminiferal records from the central and eastern equatorial Pacific that show a mid-Holocene minimum in <span class="hlt">ENSO</span> variance. Reduced mid-Holocene interannual δ18 O variability in Borneo coincides with an overall minimum in mean δ18 O from 3.5 to 5.5 kyr BP. Persistent warm pool convection would tend to enhance the Walker circulation during the mid-Holocene, which likely contributed to reduced <span class="hlt">ENSO</span> variance during this period. This finding implies that both convective intensity and interannual variability in Borneo are driven by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.3799C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.3799C"><span>A possible explanation for the divergent projection of <span class="hlt">ENSO</span> amplitude change under global warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Lin; Li, Tim; Yu, Yongqiang; Behera, Swadhin K.</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is the greatest climate variability on interannual time scale, yet what controls <span class="hlt">ENSO</span> amplitude changes under global warming (GW) is uncertain. Here we show that the fundamental factor that controls the divergent projections of <span class="hlt">ENSO</span> amplitude change within 20 coupled general circulation models that participated in the Coupled Model Intercomparison Project phase-5 is the change of climatologic mean Pacific subtropical cell (STC), whose strength determines the meridional structure of <span class="hlt">ENSO</span> perturbations and thus the anomalous thermocline response to the wind forcing. The change of the thermocline response is a key factor regulating the strength of Bjerknes thermocline and zonal advective feedbacks, which ultimately lead to the divergent changes in <span class="hlt">ENSO</span> amplitude. Furthermore, by forcing an ocean general circulation mode with the change of zonal mean zonal wind stress estimated by a simple theoretical model, a weakening of the STC in future is obtained. Such a change implies that <span class="hlt">ENSO</span> variability might strengthen under GW, which could have a profound socio-economic consequence.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612884W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612884W"><span><span class="hlt">ENSO</span> impacts on flood risk at the global scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ward, Philip; Dettinger, Michael; Jongman, Brenden; Kummu, Matti; Winsemius, Hessel</p> <p>2014-05-01</p> <p>We present the impacts of El Niño Southern Oscillation (<span class="hlt">ENSO</span>) on society and the economy, via relationships between <span class="hlt">ENSO</span> and the hydrological cycle. We also discuss ways in which this knowledge can be used in disaster risk management and risk reduction. This contribution provides the most recent results of an ongoing 4-year collaborative research initiative to assess and map the impacts of large scale interannual climate variability on flood hazard and risk at the global scale. We have examined anomalies in flood risk between <span class="hlt">ENSO</span> phases, whereby flood risk is expressed in terms of indicators such as: annual expected damage; annual expected affected population; annual expected affected Gross Domestic Product (GDP). We show that large anomalies in flood risk occur during El Niño or La Niña years in basins covering large parts of the Earth's surface. These anomalies reach statistical significance river basins covering almost two-thirds of the Earth's surface. Particularly strong anomalies exist in southern Africa, parts of western Africa, Australia, parts of Central Eurasia (especially for El Niño), the western USA (especially La Niña anomalies), and parts of South America. We relate these anomalies to possible causal relationships between <span class="hlt">ENSO</span> and flood hazard, using both modelled and observed data on flood occurrence and extremity. The implications for flood risk management are many-fold. In those regions where disaster risk is strongly influenced by <span class="hlt">ENSO</span>, the potential predictably of <span class="hlt">ENSO</span> could be used to develop probabilistic flood risk projections with lead times up to several seasons. Such data could be used by the insurance industry in managing risk portfolios and by multinational companies for assessing the robustness of their supply chains to potential flood-related interruptions. Seasonal forecasts of <span class="hlt">ENSO</span> influence of peak flows could also allow for improved flood early warning and regulation by dam operators, which could also reduce overall risks</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9237W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9237W"><span>The role of Indonesian convection in the interaction between the Indian Ocean and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieners, Claudia; Dijkstra, Henk; de Ruijter, Will</p> <p>2017-04-01</p> <p>In recent years it has been discussed whether a cool West Indian Ocean (WIO) or negative Indian Ocean Dipole (IOD) in boreal autumn favours El Niño at a lead time of 15 months (Izumo et al, 2010; Wieners et al, 2016). Observational evidence suggests that a cool WIO or negative IOD might be accompanied by easterlies over the West Pacific, though it is hard to disentangle influences of the Indian Ocean and <span class="hlt">ENSO</span> through data analysis. Such easterlies can enhance the West Pacific Warm Water Volume, thus favouring El Niño development from the following boreal spring onward. However, the Gill response to a cool WIO (negative IOD) forcing would lead to westerly (nearly zero) winds over the WPO. We hypothesise that a cool WIO or negative IOD leads to low-level air convergence and hence enhanced convectional heating over the Maritime Continent (MC), which in turn amplifies the wind convergence such as to cause easterly winds over the West Pacific. This hypothesis is tested by adding a simplified Indian Ocean and a simple convective feedback over the MC to a Zebiak-Cane model. We confirm that for a sufficiently strong convection feedback a cool WIO or negative IOD indeed leads to easterlies over the WPO. The response IO cooling over the whole zonal width of the basin (negative Indian Ocean Basinwide warming / IOB) is still westerly, with the direct Gill response dominating over convection-induced winds. Positive (negative) IOB events typically occur a few months after El Niño (La Niña) - observed correlations are about 0.9 - and cause easterlies (westerlies) over the Pacific, facilitating the switch to the opposite <span class="hlt">ENSO</span> phase, hence IOB variability dampens the <span class="hlt">ENSO</span> mode and reduces its period. The IOD, on the other hand, tends to be positive (negative) a few months prior to El Niño (La Niña) and trigger westerlies (easterlies) favouring <span class="hlt">ENSO</span> development. However, the observed correlation between IOD and <span class="hlt">ENSO</span> is only about 0.6, i.e. the IOD is less closely liked to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3602995','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3602995"><span>Recent Status Scores for Version 6 of the Addiction Severity Index (<span class="hlt">ASI</span>-6)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cacciola, John S.; Alterman, Arthur I; Habing, Brian; McLellan, A. Thomas</p> <p>2012-01-01</p> <p>Aims To describe the derivation of Recent Status Scores (RSSs) for Version 6 of the Addiction Severity Index (<span class="hlt">ASI</span>-6). Design 118 <span class="hlt">ASI</span>-6 recent status items were subjected to nonparametric item response theory (NIRT) analyses followed by confirmatory factor analysis (CFA). Generalizability and concurrent validity of the derived scores were determined. Setting and Participants 607 recent admissions to variety of substance abuse treatment programs constituted the derivation sample; a subset (N = 254) comprised the validity sample. Measurements The <span class="hlt">ASI</span>-6 interview and a validity battery of primarily self-report questionnaires that included at least one measure corresponding to each of the seven <span class="hlt">ASI</span> domains were administered. Findings Nine summary scales describing recent status that achieved or approached both high scalability and reliability were derived; one scale for each of six areas (medical, employment/finances, alcohol, drug, legal, psychiatric), and three scales for the family/social area. Intercorrelations among the RSSs also supported the multidimensionality of the <span class="hlt">ASI</span>-6. Concurrent validity analyses yielded strong evidence supporting the validity of the six of the RSSs (Medical, Alcohol, Drug, Employment, Family/Social Problems, Psychiatric). Evidence was weaker for the Legal, Family/Social Support and Child Problems RSSs. Generalizability analyses of the scales to males versus females and whites versus blacks supported the comparability of the findings with slight exceptions. Conclusions The psychometric analyses to derive Addiction Severity Index-6 Recent Status Scores (RSSs) support the multidimensionality of the <span class="hlt">ASI</span>-6 (i.e., the relative independence of different life functioning areas), consistent with research on earlier editions of the instrument. In general, the <span class="hlt">ASI</span>-6 scales demonstrate acceptable scalability, reliability and concurrent validity. While questions remain about the generalizability of some scales to population subgroups, the overall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611667P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611667P"><span>Role of tropical Indian and Atlantic Oceans variability on <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prodhomme, Chloé; Terray, Pascal; Masson, Sebastien; Boschat, Ghyslaine</p> <p>2014-05-01</p> <p>There are strong evidences of an interaction between tropical Indian, Atlantic and Pacific Oceans. Nevertheless, these interactions remain deeply controversial. While some authors claim the tropical Indian and Atlantic oceans only play a passive role with respect to <span class="hlt">ENSO</span>, others suggest a driving role for these two basins on <span class="hlt">ENSO</span>. The mecanisms underlying these relations are not fully understood and, in the Indian Ocean, the possible role of both modes of tropical variability (the Indian Ocean Dipole (IOD) and the Indian Ocean Basin mode (IOB)) remain unclear. To better quantify and understand how the variability of the tropical Indian and Atlantic Oceans impact <span class="hlt">ENSO</span> variability, we performed two sensitivity experiments using the SINTEX-F2 coupled model. For each experiment, we suppressed the variability of SST and the air-sea coupling in either the tropical Indian Ocean or tropical Atlantic Ocean by applying a strong nudging of the SST to the observed SST climatology. In both experiments, the <span class="hlt">ENSO</span> periodicity increases. In the Atlantic experiment, our understanding of this increased periodicity is drastically limited by the strongly biased mean state in this region. Conversely, in the Indian Ocean experiment, the increase of <span class="hlt">ENSO</span> periodicity is related to the absence of the IOB following the El Niño peak, which leads to a decrease of westerly winds in the western Pacific during late winter and spring after the peak. These weaker westerlies hinders the transition to a La Niña phase and thus increase the duration and periodicity of the event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171391','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171391"><span><span class="hlt">ENSO</span> Bred Vectors in Coupled Ocean-Atmosphere General Circulation Models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yang, S. C.; Cai, Ming; Kalnay, E.; Rienecker, M.; Yuan, G.; Toth, ZA.</p> <p>2004-01-01</p> <p>The breeding method has been implemented in the NASA Seasonal-to-Interannual Prediction Project (NSIPP) Coupled General Circulation Model (CGCM) with the goal of improving operational seasonal to interannual climate predictions through ensemble forecasting and data assimilation. The coupled instability as cap'tured by the breeding method is the first attempt to isolate the evolving <span class="hlt">ENSO</span> instability and its corresponding global atmospheric response in a fully coupled ocean-atmosphere GCM. Our results show that the growth rate of the coupled bred vectors (BV) peaks at about 3 months before a background <span class="hlt">ENSO</span> event. The dominant growing BV modes are reminiscent of the background <span class="hlt">ENSO</span> anomalies and show a strong tropical response with wind/SST/thermocline interrelated in a manner similar to the background <span class="hlt">ENSO</span> mode. They exhibit larger amplitudes in the eastern tropical Pacific, reflecting the natural dynamical sensitivity associated with the presence of the shallow thermocline. Moreover, the extratropical perturbations associated with these coupled BV modes reveal the variations related to the atmospheric teleconnection patterns associated with background <span class="hlt">ENSO</span> variability, e.g. over the North Pacific and North America. A similar experiment was carried out with the NCEP/CFS03 CGCM. Comparisons between bred vectors from the NSIPP CGCM and NCEP/CFS03 CGCM demonstrate the robustness of the results. Our results strongly suggest that the breeding method can serve as a natural filter to identify the slowly varying, coupled instabilities in a coupled GCM, which can be used to construct ensemble perturbations for ensemble forecasts and to estimate the coupled background error covariance for coupled data assimilation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=self+AND+esteem+AND+online&id=EJ1154500','ERIC'); return false;" href="https://eric.ed.gov/?q=self+AND+esteem+AND+online&id=EJ1154500"><span>Discriminative and Criterion Validity of the Autism Spectrum Identity Scale (<span class="hlt">ASIS</span>)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McDonald, T. A. M.</p> <p>2017-01-01</p> <p>Individuals on the autism spectrum face stigma that can influence identity development. Previous research on the 22-item Autism Spectrum Identity Scale (<span class="hlt">ASIS</span>) reported a four-factor structure with strong split-sample cross-validation and good internal consistency. This study reports the discriminative and criterion validity of the <span class="hlt">ASIS</span> with other…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ERL....13d4031L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ERL....13d4031L"><span>Identification of symmetric and asymmetric responses in seasonal streamflow globally to <span class="hlt">ENSO</span> phase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Donghoon; Ward, Philip J.; Block, Paul</p> <p>2018-04-01</p> <p>The phase of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) has large-ranging effects on streamflow and hydrologic conditions globally. While many studies have evaluated this relationship through correlation analysis between annual streamflow and <span class="hlt">ENSO</span> indices, an assessment of potential asymmetric relationships between <span class="hlt">ENSO</span> and streamflow is lacking. Here, we evaluate seasonal variations in streamflow by <span class="hlt">ENSO</span> phase to identify asymmetric (AR) and symmetric (SR) spatial pattern responses globally and further corroborate with local precipitation and hydrological condition. The AR and SR patterns between seasonal precipitation and streamflow are identified at many locations for the first time. Our results identify strong SR patterns in particular regions including northwestern and southern US, northeastern and southeastern South America, northeastern and southern Africa, southwestern Europe, and central-south Russia. The seasonally lagged anomalous streamflow patterns are also identified and attributed to snowmelt, soil moisture, and/or cumulative hydrological processes across river basins. These findings may be useful in water resources management and natural hazards planning by better characterizing the propensity of flood or drought conditions by <span class="hlt">ENSO</span> phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP23D..04Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP23D..04Z"><span>Reduced <span class="hlt">ENSO</span> Variability at the LGM Revealed by an Isotope-enabled Earth System Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, J.; Liu, Z.; Otto-Bliesner, B. L.; Brady, E. C.; Noone, D.; Zhang, J.; Tomas, R. A.; Jahn, A.; Nusbaumer, J. M.; Wong, T. E.</p> <p>2016-12-01</p> <p>El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is the most important climate variability at interannual timescale, greatly affecting the weather and climate worldwide. Studying the <span class="hlt">ENSO</span> at the Last Glacial Maximum (LGM, 21 kyrs before present) can help us better understand its dynamics and improve its projections under anthropogenic global warming. However, both numerical simulations and paleoclimate reconstructions show contradicting results among themselves, e.g., using the Individual Foraminifera Analysis (IFA) approach, some paleo-records suggest an amplified <span class="hlt">ENSO</span> at the LGM relative to present day; while others indicate a weakened <span class="hlt">ENSO</span>. These contradictions are hard to explore using traditional climate models due to the indirect nature of model-data comparison: numerical models usually simulate variations in climate state variables (e.g., temperature); while reconstructions can only use proxies (e.g., water isotopes) to infer changes in these state variables. Here we employ the recently developed isotope-enabled Community Earth System Model (iCESM) to study the <span class="hlt">ENSO</span> strength at the LGM and attempt to provide a consistent picture between climate model and different reconstructions. We find that <span class="hlt">ENSO</span> at the LGM is about 30% weaker than that of the preindustrial in iCESM, primarily attributable to the weakened atmosphere-ocean coupled feedbacks in a colder climate with a deeper thermocline. With the capability of simulating water isotopes, our model demonstrates that total variance recorded by the IFA water-isotope records in the eastern equatorial Pacific (e.g., Core CD21-30) could actually increase because of an intensified annual cycle, instead of an amplified <span class="hlt">ENSO</span>. Furthermore, our isotope-enabled simulations suggest that caution should be applied when interpreting the subsurface IFA water-isotope records (e.g., Cores CD38-17P and MD02-2529) due to the wide spread of habitat depth of thermocline-dwelling foraminifera and their possible migration with temporally varying</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.1157K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.1157K"><span><span class="hlt">ENSO</span> and East Asian winter monsoon relationship modulation associated with the anomalous northwest Pacific anticyclone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Ji-Won; An, Soon-Il; Jun, Sang-Yoon; Park, Hey-Jin; Yeh, Sang-Wook</p> <p>2017-08-01</p> <p>Using observational datasets and numerical model experiments, the mechanism on the slowly varying change in the relationship between the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and the East Asian winter monsoon (EAWM) is investigated. The decadal-window (11-, 15-, and 21-year) moving correlations show a significant change in the boreal wintertime <span class="hlt">ENSO</span>-EAWM relationship between two sub-periods of 1976‒1992 and 1997‒2013. Such recent change in <span class="hlt">ENSO</span>-EAWM relationship is mainly attributed to the changes in the intensity and zonal location of the anomalous lower-tropospheric northwest Pacific anticyclone (NWP-AC). NWP-AC commonly develops near the region of the Philippine Sea during the <span class="hlt">ENSO</span>'s peak phase and plays an important role of bridging the tropical convection and mid-latitude teleconnection. On one hand, the intensity of the NWP-AC is influenced by the interdecadal variation in a linkage between <span class="hlt">ENSO</span> and the Indian Ocean sea surface temperature (SST) variability, referring that a strong connection between the Pacific and Indian Oceans results in the strengthening of NWP-AC response to <span class="hlt">ENSO</span>. On the other hand, the zonal displacement of the NWP-AC is associated with the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). That is, the tropical Pacific mean state (i.e., zonal SST gradient between climatologically warm western Pacific and cold eastern Pacific)—strengthened by either the negative PDO phase or the positive AMO phase—drives the anomalous <span class="hlt">ENSO</span>-induced convection to be shifted to the west. With this westward shift, the zonal center of the NWP-AC also migrates westward over the Philippine Islands and exerts stronger connection between <span class="hlt">ENSO</span> and EAWM. In contrast, the relaxed zonal SST contrast associated with either the positive PDO phase or the negative AMO phase tends to exhibit weaker <span class="hlt">ENSO</span>-EAWM relationship via both of eastward shifted zonal centers of the anomalous <span class="hlt">ENSO</span>-induced convection and the NWP-AC. Finally, a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..889W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..889W"><span>Modulation of <span class="hlt">ENSO</span> evolution by strong tropical volcanic eruptions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Tao; Guo, Dong; Gao, Yongqi; Wang, Huijun; Zheng, Fei; Zhu, Yali; Miao, Jiapeng; Hu, Yongyun</p> <p>2017-11-01</p> <p>The simulated responses of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) to volcanic forcings are controversial, and some mechanisms of these responses are not clear. We investigate the impacts of volcanic forcing on the <span class="hlt">ENSO</span> using a long-term simulation covering 1400-1999 as simulated by the Bergen Climate Model (BCM) and a group of simulations performed with the Community Atmosphere Model version 4.0 (CAM4) and the BCM's ocean component Miami Isopycanic Coordinated Ocean Model (MICOM). The analysis of the long-term BCM simulation indicates that <span class="hlt">ENSO</span> has a negative-positive-negative response to strong tropical volcanic eruptions (SVEs), which corresponds to the different stages of volcanic forcing. In the initial forcing stage, a brief and weak La Niña-like response is caused by the cooling along the west coast of the South American continent and associated enhancement of the trade winds. In the peak forcing stage, westerly wind anomalies are excited by both reduced east-west sea level pressure gradients and weakened and equatorward shifted tropical convergence zones. These westerly wind anomalies extend to the equatorial eastern Pacific, leading to an El Niño-like response. At the same time, easterly wind anomalies west of 120°E and strong cooling effects can promote a discharged thermocline state and excite an upwelling Kelvin wave in the western Pacific. In the declining forcing stage, forced by the recovered trade winds, the upwelling Kelvin wave propagates eastward and reaches the equatorial eastern Pacific. Through the Bjerknes feedback, a strong and temporally extended La Niña-like response forms. Additional CAM4 simulations suggest a more important role of the surface cooling over the Maritime Continent and surrounding ocean in shaping the westerly wind anomalies over the equatorial central-eastern Pacific and the easterly wind anomalies west of 120° E, which are key to causing the El Niño-like responses and subsequent La Niña-like responses</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22492127-structural-properties-si-films-effect-aluminum-induced-crystallization','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22492127-structural-properties-si-films-effect-aluminum-induced-crystallization"><span>Structural properties of <span class="hlt">a-Si</span> films and their effect on aluminum induced crystallization</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tankut, Aydin; Ozkol, Engin; Karaman, Mehmet</p> <p>2015-10-15</p> <p>In this paper, we report the influence of the structural properties of amorphous silicon (<span class="hlt">a-Si</span>) on its subsequent crystallization behavior via the aluminum induced crystallization (AIC) method. Two distinct <span class="hlt">a-Si</span> deposition techniques, electron beam evaporation and plasma enhanced chemical vapor deposition (PECVD), are compared for their effect on the overall AIC kinetics as well as the properties of the final poly-crystalline (poly-Si) silicon film. Raman and FTIR spectroscopy results indicate that the PECVD grown <span class="hlt">a-Si</span> films has higher intermediate-range order, which is enhanced for increased hydrogen dilution during deposition. With increasing intermediate-range order of the <span class="hlt">a-Si</span>, the rate of AICmore » is diminished, leading larger poly-Si grain size.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20180000959&hterms=earth+system&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dearth%2Bsystem','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20180000959&hterms=earth+system&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dearth%2Bsystem"><span>Reduced <span class="hlt">ENSO</span> Variability at the LGM Revealed by an Isotope-Enabled Earth System Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhu, Jiang; Liu, Zhengyu; Brady, Esther; Otto-Bliesner, Bette; Zhang, Jiaxu; Noone, David; Tomas, Robert; Nusbaumer, Jesse; Wong, Tony; Jahn, Alexandra; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20180000959'); toggleEditAbsImage('author_20180000959_show'); toggleEditAbsImage('author_20180000959_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20180000959_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20180000959_hide"></p> <p>2017-01-01</p> <p>Studying the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) in the past can help us better understand its dynamics and improve its future projections. However, both paleoclimate reconstructions and model simulations of <span class="hlt">ENSO</span> strength at the Last Glacial Maximum (LGM; 21 ka B.P.) have led to contradicting results. Here we perform model simulations using the recently developed water isotope-enabled Community Earth System Model (iCESM). For the first time, model-simulated oxygen isotopes are directly compared with those from <span class="hlt">ENSO</span> reconstructions using the individual foraminifera analysis (IFA). We find that the LGM <span class="hlt">ENSO</span> is most likely weaker comparing with the preindustrial. The iCESM suggests that total variance of the IFA records may only reflect changes in the annual cycle instead of <span class="hlt">ENSO</span> variability as previously assumed. Furthermore, the interpretation of subsurface IFA records can be substantially complicated by the habitat depth of thermocline-dwelling foraminifera and their vertical migration with a temporally varying thermocline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28781392','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28781392"><span>On the role of ozone feedback in the <span class="hlt">ENSO</span> amplitude response under global warming.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nowack, Peer J; Braesicke, Peter; Luke Abraham, N; Pyle, John A</p> <p>2017-04-28</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) in the tropical Pacific Ocean is of key importance to global climate and weather. However, state-of-the-art climate models still disagree on the <span class="hlt">ENSO</span>'s response under climate change. The potential role of atmospheric ozone changes in this context has not been explored before. Here we show that differences between typical model representations of ozone can have a first-order impact on <span class="hlt">ENSO</span> amplitude projections in climate sensitivity simulations. The vertical temperature gradient of the tropical middle-to-upper troposphere adjusts to ozone changes in the upper troposphere and lower stratosphere, modifying the Walker circulation and consequently tropical Pacific surface temperature gradients. We show that neglecting ozone changes thus results in a significant increase in the number of extreme <span class="hlt">ENSO</span> events in our model. Climate modeling studies of the <span class="hlt">ENSO</span> often neglect changes in ozone. We therefore highlight the need to understand better the coupling between ozone, the tropospheric circulation, and climate variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A53E2302N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A53E2302N"><span>On the role of ozone feedback in the <span class="hlt">ENSO</span> amplitude response under global warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nowack, P. J.; Braesicke, P.; Abraham, N. L.; Pyle, J. A.</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) in the tropical Pacific is of key importance to global climate and weather. However, climate models still disagree on the <span class="hlt">ENSO</span>'s response under climate change. Here we show that typical model representations of ozone can have a first-order impact on <span class="hlt">ENSO</span> amplitude projections in climate sensitivity simulations (i.e. standard abrupt 4xCO2). We mainly explain this effect by the lapse rate adjustment of the tropical troposphere to ozone changes in the upper troposphere and lower stratosphere (UTLS) under 4xCO2. The ozone-induced lapse rate changes modify the Walker circulation response to the CO2 forcing and consequently tropical Pacific surface temperature gradients. Therefore, not including ozone feedbacks increases the number of extreme <span class="hlt">ENSO</span> events in our model. In addition, we demonstrate that even if ozone changes in the tropical UTLS are included in the simulations, the neglect of the ozone response in the middle-upper stratosphere still leads to significantly larger <span class="hlt">ENSO</span> amplitudes (compared to simulations run with a fully interactive atmospheric chemistry scheme). Climate modeling studies of the <span class="hlt">ENSO</span> often neglect changes in ozone. Our results imply that this could affect the inter-model spread found in <span class="hlt">ENSO</span> projections and, more generally, surface climate change simulations. We discuss the additional complexity in quantifying such ozone-related effects that arises from the apparent model dependency of chemistry-climate feedbacks and, possibly, their range of surface climate impacts. In conclusion, we highlight the need to understand better the coupling between ozone, the tropospheric circulation, and climate variability. Reference: Nowack PJ, Braesicke P, Abraham NL, and Pyle JA (2017), On the role of ozone feedback in the <span class="hlt">ENSO</span> amplitude response under global warming, Geophys. Res. Lett. 44, 3858-3866, doi:10.1002/2016GL072418.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.U53F..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.U53F..03S"><span>The <span class="hlt">ENSO</span>-pandemic influenza connection: coincident or causal?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shaman, J. L.; Lipsitch, M.</p> <p>2011-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is a coupled ocean-atmosphere system in the tropical Pacific, which affects weather conditions, including temperatures, precipitation, winds and storm activity, across the planet. <span class="hlt">ENSO</span> has two extreme phases marked by either warmer (El Niño) or cooler (La Niña) than average sea surface temperatures in the central equatorial Pacific. We find that the 4 most recent human influenza pandemics (1918, 1957, 1968, 2009), all of which were first identified in boreal spring or summer, were preceded by La Niña conditions in the equatorial Pacific. Changes in <span class="hlt">ENSO</span> have been shown to alter the migration, stopover time, fitness and interspecies mixing of migratory birds, and consequently likely affect their mixing with domestic animals. We hypothesize that La Niña conditions bring divergent influenza subtypes together in some parts of the world and favor the reassortment of influenza through simultaneous multiple infection of individual hosts and the generation of novel pandemic strains. We propose approaches to test this hypothesis using influenza population genetics, virus prevalence in various host species, and avian migration patterns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45.1939P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45.1939P"><span>Ocean Chlorophyll as a Precursor of <span class="hlt">ENSO</span>: An Earth System Modeling Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Jong-Yeon; Dunne, John P.; Stock, Charles A.</p> <p>2018-02-01</p> <p>Ocean chlorophyll concentration, a proxy for phytoplankton, is strongly influenced by internal ocean dynamics such as those associated with El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Observations show that ocean chlorophyll responses to <span class="hlt">ENSO</span> generally lead sea surface temperature (SST) responses in the equatorial Pacific. A long-term global Earth system model simulation incorporating marine biogeochemical processes also exhibits a preceding chlorophyll response. In contrast to simulated SST anomalies, which significantly lag the wind-driven subsurface heat response to <span class="hlt">ENSO</span>, chlorophyll anomalies respond rapidly. Iron was found to be the key factor connecting the simulated surface chlorophyll anomalies to the subsurface ocean response. Westerly wind bursts decrease central Pacific chlorophyll by reducing iron supply through wind-driven thermocline deepening but increase western Pacific chlorophyll by enhancing the influx of coastal iron from the maritime continent. Our results mechanistically support the potential for chlorophyll-based indices to inform seasonal <span class="hlt">ENSO</span> forecasts beyond previously identified SST-based indices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48.2859R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48.2859R"><span>Tracking the delayed response of the northern winter stratosphere to <span class="hlt">ENSO</span> using multi reanalyses and model simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ren, Rongcai; Rao, Jian; Wu, Guoxiong; Cai, Ming</p> <p>2017-05-01</p> <p>The concurrent effects of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on the northern winter stratosphere have been widely recognized; however, the delayed effects of <span class="hlt">ENSO</span> in the next winter after mature <span class="hlt">ENSO</span> have yet to be confirmed in multi reanalyses and model simulations. This study uses three reanalysis datasets, a long-term fully coupled model simulation, and a high-top general circulation model to examine <span class="hlt">ENSO</span>'s delayed effects in the stratosphere. The warm-minus-cold composite analyses consistently showed that, except those quick-decaying quasi-biennial <span class="hlt">ENSO</span> events that reverse signs during July-August-September (JAS) in their decay years, <span class="hlt">ENSO</span> events particularly those quasi-quadrennial (QQ) that persist through JAS, always have a significant effect on the extratropical stratosphere in both the concurrent winter and the next winter following mature <span class="hlt">ENSO</span>. During the concurrent winter, the QQ <span class="hlt">ENSO</span>-induced Pacific-North American (PNA) pattern corresponds to an anomalous wavenumber-1 from the upper troposphere to the stratosphere, which acts to intensify/weaken the climatological wave pattern during warm/cold <span class="hlt">ENSO</span>. Associated with the zonally quasi-homogeneous tropical forcing in spring of the QQ <span class="hlt">ENSO</span> decay years, there appear persistent and zonally quasi-homogeneous temperature anomalies in the midlatitudes from the upper troposphere to the lower stratosphere until summer. With the reduction in <span class="hlt">ENSO</span> forcing and the PNA responses in the following winter, an anomalous wavenumber-2 prevails in the extratropics. Although the anomalous wave flux divergence in the upper stratospheric layer is still dominated by wavenumber-1, it is mainly caused by wavenumber-2 in the lower stratosphere. However, the wavenumber-2 activity in the next winter is always underestimated in the model simulations, and wavenumber-1 activity dominates in both winters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.noaa.gov/topic-tags/el-nino-la-nina-enso','SCIGOVWS'); return false;" href="http://www.noaa.gov/topic-tags/el-nino-la-nina-enso"><span>El Nino, La Nina, <span class="hlt">ENSO</span> | National Oceanic and Atmospheric Administration</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>your local weather Enter your ZIP code GO Enter Search Terms El Nino, <em>La</em> Nina, <span class="hlt">ENSO</span> Content <em>La</em> Nina is gone, for now May 10, 2018 More On El Nino, <em>La</em> Nina, <span class="hlt">ENSO</span> Ocean surface temperatures in April 2018 compared to the 1981-2010 average. What's going on with <em>La</em> Niña? March 22, 2018 More On El Nino, <em>La</em> Nina</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1376649-global-land-carbon-sink-response-temperature-precipitation-varies-enso-phase','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1376649-global-land-carbon-sink-response-temperature-precipitation-varies-enso-phase"><span>Global land carbon sink response to temperature and precipitation varies with <span class="hlt">ENSO</span> phase</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Fang, Yuanyuan; Michalak, Anna M.; Schwalm, Christopher R.; ...</p> <p>2017-06-01</p> <p>Climate variability associated with the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and its consequent impacts on land carbon sink interannual variability have been used as a basis for investigating carbon cycle responses to climate variability more broadly, and to inform the sensitivity of the tropical carbon budget to climate change. Past studies have presented opposing views about whether temperature or precipitation is the primary factor driving the response of the land carbon sink to <span class="hlt">ENSO</span>. We show that the dominant driver varies with <span class="hlt">ENSO</span> phase. And whereas tropical temperature explains sink dynamics following El Niño conditions (r TG,P = 0.59, p <more » 0.01), the post La Niña sink is driven largely by tropical precipitation (r PG,T= -0.46, p = 0.04). This finding points to an <span class="hlt">ENSO</span>-phase-dependent interplay between water availability and temperature in controlling the carbon uptake response to climate variations in tropical ecosystems. Furthermore, we find that none of a suite of ten contemporary terrestrial biosphere models captures these <span class="hlt">ENSO</span>-phase-dependent responses, highlighting a key uncertainty in modeling climate impacts on the future of the global land carbon sink.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1406686-global-land-carbon-sink-response-temperature-precipitation-varies-enso-phase','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1406686-global-land-carbon-sink-response-temperature-precipitation-varies-enso-phase"><span>Global land carbon sink response to temperature and precipitation varies with <span class="hlt">ENSO</span> phase</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fang, Yuanyuan; Michalak, Anna M.; Schwalm, Christopher R.</p> <p></p> <p>Climate variability associated with the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and its consequent impacts on land carbon sink interannual variability have been used as a basis for investigating carbon cycle responses to climate variability more broadly, and to inform the sensitivity of the tropical carbon budget to climate change. Past studies have presented opposing views about whether temperature or precipitation is the primary factor driving the response of the land carbon sink to <span class="hlt">ENSO</span>. Here, we show that the dominant driver varies with <span class="hlt">ENSO</span> phase. Whereas tropical temperature explains sink dynamics following El Niño conditions (r TG,P=0.59, p<0.01), the post Lamore » Niña sink is driven largely by tropical precipitation (r PG,T=-0.46, p=0.04). This finding points to an <span class="hlt">ENSO</span>-phase-dependent interplay between water availability and temperature in controlling the carbon uptake response to climate variations in tropical ecosystems. We further find that none of a suite of ten contemporary terrestrial biosphere models captures these <span class="hlt">ENSO</span>-phase-dependent responses, highlighting a key uncertainty in modeling climate impacts on the future of the global land carbon sink.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1376649','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1376649"><span>Global land carbon sink response to temperature and precipitation varies with <span class="hlt">ENSO</span> phase</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fang, Yuanyuan; Michalak, Anna M.; Schwalm, Christopher R.</p> <p></p> <p>Climate variability associated with the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and its consequent impacts on land carbon sink interannual variability have been used as a basis for investigating carbon cycle responses to climate variability more broadly, and to inform the sensitivity of the tropical carbon budget to climate change. Past studies have presented opposing views about whether temperature or precipitation is the primary factor driving the response of the land carbon sink to <span class="hlt">ENSO</span>. We show that the dominant driver varies with <span class="hlt">ENSO</span> phase. And whereas tropical temperature explains sink dynamics following El Niño conditions (r TG,P = 0.59, p <more » 0.01), the post La Niña sink is driven largely by tropical precipitation (r PG,T= -0.46, p = 0.04). This finding points to an <span class="hlt">ENSO</span>-phase-dependent interplay between water availability and temperature in controlling the carbon uptake response to climate variations in tropical ecosystems. Furthermore, we find that none of a suite of ten contemporary terrestrial biosphere models captures these <span class="hlt">ENSO</span>-phase-dependent responses, highlighting a key uncertainty in modeling climate impacts on the future of the global land carbon sink.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMOS31B1400Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMOS31B1400Z"><span>Potential role of salinity in <span class="hlt">ENSO</span> and MJO predictions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, J.; Kumar, A.; Murtugudde, R. G.; Xie, P.</p> <p>2017-12-01</p> <p>Studies have suggested that ocean salinity can vary in response to <span class="hlt">ENSO</span> and MJO. For example, during an El Niño event, sea surface salinity decreases in the western and central equatorial Pacific, as a result of zonal advection of low salinity water by anomalous eastward surface currents, and to a lesser extent as a result of a rainfall excess associated with atmospheric convection and warm water displacements. However, the effect of salinity on <span class="hlt">ENSO</span> and MJO evolutions and their forecasts has been less explored. In this analysis, we explored the potential role of salinity in <span class="hlt">ENSO</span> and MJO predictions by conducting sensitivity experiments with NCEP CFSv2. Firstly, two forecasts experiments are conducted to explore its effect on <span class="hlt">ENSO</span> predictions, in which the interannual variability of salinity in the ocean initial states is either included or excluded. Comparisons suggested that the salinity variability is essential to correctly forecast the 2007/08 La Niña starting from April 2007. With realistic salinity initial states, the tendency to decay of the subsurface cold condition during the spring and early summer 2007 was interrupted by positive salinity anomalies in the upper central Pacific, which working together with the Bjerknes positive feedback, contributed to the development of the La Niña event. Our study suggests that <span class="hlt">ENSO</span> forecasts will benefit from more accurate sustained salinity observations having large-scale spatial coverage. We also assessed the potential role of salinity in MJO by evaluating a long coupled free run that has a relatively realistic MJO simulation and a set of predictability experiment, both based on CFSv2. Diagnostics of the free run suggest that, while the intraseasonal SST variations lead convections by a quarter cycle, they are almost in phase only with changes in barrier layer thickness, thereby suggesting an active role of salinity on SST. Its effect on MJO predictions is further explored by controlling the surface salinity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41B1013C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41B1013C"><span><span class="hlt">ENSO</span> Diversity Changes Due To Global Warming In CESM-LE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carreric, A.; Dewitte, B.; Guemas, V.</p> <p>2017-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is predicted to be modified due to global warming based on the CMIP3 and CMIP5 data bases. In particular the frequency of occurrence of extreme Eastern Pacific El Niño events is to double in the future in response to the increase in green-house gazes. Such forecast relies however on state-of-the-art models that still present mean state biases and do not simulate realistically key features of El Niño events such as its diversity which is related to the existence of at least two types of El Niño events, the Eastern Pacific (EP) El Nino and the Central Pacific (CP) El Niño events. Here we take advantage of the Community Earth System Model (CESM) Large Ensemble (LE) that provides 35 realizations of the climate of the 1920-2100 period with a combination of both natural and anthropogenic climate forcing factors, to explore on the one hand methods to detect changes in <span class="hlt">ENSO</span> statistics and on the other hand to investigate changes in thermodynamical processes associated to the increase oceanic stratification owed to global warming. The CESM simulates realistically many aspects of the <span class="hlt">ENSO</span> diversity, in particular the non-linear evolution of the phase space of the first two EOF modes of Sea Surface Temperature (SST) anomalies in the tropical Pacific. Based on indices accounting for the two <span class="hlt">ENSO</span> regimes used in the literature, we show that, although there is no statistically significant (i.e. confidence level > 95%) changes in the occurrence of El Niño types from the present to the future climate, the estimate of the changes is sensitive to the definition of <span class="hlt">ENSO</span> indices that is used. CESM simulates in particular an increase occurrence of extreme El Niño events that can vary by 28% from one method to the other. It is shown that the seasonal evolution of EP El Niño events is modified from the present to the future climate, with in particular a larger occurrence of events taking place in Austral summer in the warmer climate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2334L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2334L"><span>A metric for quantifying El Niño pattern diversity with implications for <span class="hlt">ENSO</span>-mean state interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lemmon, Danielle E.; Karnauskas, Kristopher B.</p> <p>2018-04-01</p> <p>Recent research on the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon increasingly reveals the highly complex and diverse nature of <span class="hlt">ENSO</span> variability. A method of quantifying <span class="hlt">ENSO</span> spatial pattern uniqueness and diversity is presented, which enables (1) formally distinguishing between unique and "canonical" El Niño events, (2) testing whether historical model simulations aptly capture <span class="hlt">ENSO</span> diversity by comparing with instrumental observations, (3) projecting future <span class="hlt">ENSO</span> diversity using future model simulations, (4) understanding the dynamics that give rise to <span class="hlt">ENSO</span> diversity, and (5) analyzing the associated diversity of <span class="hlt">ENSO</span>-related atmospheric teleconnection patterns. Here we develop a framework for measuring El Niño spatial SST pattern uniqueness and diversity for a given set of El Niño events using two indices, the El Niño Pattern Uniqueness (EPU) index and El Niño Pattern Diversity (EPD) index, respectively. By applying this framework to instrumental records, we independently confirm a recent regime shift in El Niño pattern diversity with an increase in unique El Niño event sea surface temperature patterns. However, the same regime shift is not observed in historical CMIP5 model simulations; moreover, a comparison between historical and future CMIP5 model scenarios shows no robust change in future <span class="hlt">ENSO</span> diversity. Finally, we support recent work that asserts a link between the background cooling of the eastern tropical Pacific and changes in <span class="hlt">ENSO</span> diversity. This robust link between an eastern Pacific cooling mode and <span class="hlt">ENSO</span> diversity is observed not only in instrumental reconstructions and reanalysis, but also in historical and future CMIP5 model simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GMD....10.1467C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GMD....10.1467C"><span><span class="hlt">ASIS</span> v1.0: an adaptive solver for the simulation of atmospheric chemistry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cariolle, Daniel; Moinat, Philippe; Teyssèdre, Hubert; Giraud, Luc; Josse, Béatrice; Lefèvre, Franck</p> <p>2017-04-01</p> <p>This article reports on the development and tests of the adaptive semi-implicit scheme (<span class="hlt">ASIS</span>) solver for the simulation of atmospheric chemistry. To solve the ordinary differential equation systems associated with the time evolution of the species concentrations, <span class="hlt">ASIS</span> adopts a one-step linearized implicit scheme with specific treatments of the Jacobian of the chemical fluxes. It conserves mass and has a time-stepping module to control the accuracy of the numerical solution. In idealized box-model simulations, <span class="hlt">ASIS</span> gives results similar to the higher-order implicit schemes derived from the Rosenbrock's and Gear's methods and requires less computation and run time at the moderate precision required for atmospheric applications. When implemented in the MOCAGE chemical transport model and the Laboratoire de Météorologie Dynamique Mars general circulation model, the <span class="hlt">ASIS</span> solver performs well and reveals weaknesses and limitations of the original semi-implicit solvers used by these two models. <span class="hlt">ASIS</span> can be easily adapted to various chemical schemes and further developments are foreseen to increase its computational efficiency, and to include the computation of the concentrations of the species in aqueous-phase in addition to gas-phase chemistry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC32B..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC32B..04S"><span>An Ensemble Approach to Understanding the <span class="hlt">ENSO</span> Response to Climate Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stevenson, S.; Capotondi, A.; Fasullo, J.; Otto-Bliesner, B. L.</p> <p>2017-12-01</p> <p>The dynamics of the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) are known to be sensitive to changes in background climate conditions, as well as atmosphere/ocean feedbacks. However, the degree to which shifts in <span class="hlt">ENSO</span> characteristics can be robustly attributed to external climate forcings remains unknown. Efforts to assess these changes in a multi-model framework are subject to uncertainties due to both differing model physics and internal <span class="hlt">ENSO</span> variability. New community ensembles created at the National Center for Atmospheric Research and the NOAA Geophysical Fluid Dynamics Laboratory are ideally suited to addressing this problem, providing many realizations of the climate of the 850-2100 period with a combination of both natural and anthropogenic climate forcing factors. Here we analyze the impacts of external forcing on El Nino and La Nina evolution using four sets of simulations: the CESM Last Millennium Ensemble (CESM-LME), which covers the 850-2005 period and provides long-term context for forced responses; the Large Ensemble (CESM-LE), which includes 20th century and 21st century (RCP8.5) projections; the Medium Ensemble (CESM-ME), which is composed of 21st century RCP4.5 projections; and a large ensemble with the GFDL ESM2M, which includes 20th century and RCP8.5 projections. In the CESM, <span class="hlt">ENSO</span> variance increases slightly over the 20th century in all ensembles, with the effects becoming much larger during the 21st. The slower increase in variance over the 20th century is shown to arise from compensating influences from greenhouse gas (GHG) and anthropogenic aerosol emissions, which give way to GHG-dominated effects by 2100. However, the 21st century variance increase is not robust: CESM and the ESM2M differ drastically in their <span class="hlt">ENSO</span> projections. The mechanisms for these inter-model differences are discussed, as are the implications for the design of future multi-model <span class="hlt">ENSO</span> projection experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JASTP.167...30L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JASTP.167...30L"><span>Can solar cycle modulate the <span class="hlt">ENSO</span> effect on the Pacific/North American pattern?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Delin; Xiao, Ziniu</p> <p>2018-01-01</p> <p>The <span class="hlt">ENSO</span> effect on the Pacific/North American pattern (PNA) is well-known robust. Recent studies from observations and model simulations have reported that some important atmospheric circulation systems of extratropics are markedly modulated by the 11-year solar cycle. But less effort has been devoted to revealing the solar influence on the PNA. We thus hypothesize that the instability and uncertainty in the relationship between solar activity and PNA could be due to the <span class="hlt">ENSO</span> impacts. In this study, solar cycle modulation of the <span class="hlt">ENSO</span> effect on the PNA has been statistically examined by the observations from NOAA and NCEP/NCAR for the period of 1950-2014. Results indicate that during the high solar activity (HS) years, the PNA has stronger relevance to the <span class="hlt">ENSO</span>, and the response of tropospheric geopotential height to <span class="hlt">ENSO</span> variability is broadly similar to the typical positive PNA pattern. However, in the case of low solar activity (LS) years, the correlation between <span class="hlt">ENSO</span> and PNA decreases relatively and the response has some resemblance to the negative phase of Arctic Oscillation (AO). Also, we find the impacts of solar activity on the middle troposphere are asymmetric during the different solar cycle phases, and the weak PNA-like response to solar activity only presents in the HS years. Closer inspection suggests that the higher solar activity has a much more remarkable modulation on the PNA-like response to the warm <span class="hlt">ENSO</span> (WE) than that to the cold <span class="hlt">ENSO</span> (CE), particularly over the Northeast Pacific region. The possible cause of the different responses might be the solar influence on the subtropical westerlies of upper troposphere. When the sea surface temperature (SST) of east-central tropical Pacific is anomalously warm, the upper tropospheric westerlies are significantly modulated by the higher solar activity, resulting in the acceleration and eastward shift of the North Pacific subtropical jet, which favors the propagation of WE signal from the tropical Pacific</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.9093L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.9093L"><span><span class="hlt">ENSO</span>-based probabilistic forecasts of March-May U.S. tornado and hail activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lepore, Chiara; Tippett, Michael K.; Allen, John T.</p> <p>2017-09-01</p> <p>Extended logistic regression is used to predict March-May severe convective storm (SCS) activity based on the preceding December-February (DJF) El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) state. The spatially resolved probabilistic forecasts are verified against U.S. tornado counts, hail events, and two environmental indices for severe convection. The cross-validated skill is positive for roughly a quarter of the U.S. Overall, indices are predicted with more skill than are storm reports, and hail events are predicted with more skill than tornado counts. Skill is higher in the cool phase of <span class="hlt">ENSO</span> (La Niña like) when overall SCS activity is higher. SCS forecasts based on the predicted DJF <span class="hlt">ENSO</span> state from coupled dynamical models initialized in October of the previous year extend the lead time with only a modest reduction in skill compared to forecasts based on the observed DJF <span class="hlt">ENSO</span> state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986SPIE..617..102S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986SPIE..617..102S"><span><span class="hlt">A-Si</span> Photoreceptors At The Threshold Of Industrial Application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Senske, W.; Marschall, N.</p> <p>1986-03-01</p> <p><span class="hlt">A-Si</span> has become an attractive alternative for conventional electrophotographic photoreceptors. <span class="hlt">A-Si</span> photoreceptors have been prepared by other laboratories by plasma deposition with blocking and protection layers. These photoreceptors are highly photosensitive and show low fatigue. Using sputtering we have shown that this technique is capable of produc-ing films with high charge acceptance. The increase of the deposition rate is presently un-der intensive investigation. High rates can be achieved by a higher degree of silane decomposition or by magnetron sputtering together with a higher power level. Deposition rates of more than 20 pm/h have been obtained by both techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70118019','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70118019"><span>Influence of El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) events on the evolution of central California's shoreline</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Storlazzi, Curt D.; Griggs, Gary B.</p> <p>2000-01-01</p> <p>Significant sea-cliff erosion and storm damage occurred along the central coast of California during the 1982–1983 and 1997–1998 El Niño winters. This generated interest among scientists and land-use planners in how historic El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) winters have affected the coastal climate of central California. A relative <span class="hlt">ENSO</span> intensity index based on oceanographic and meteorologic data defines the timing and magnitude of <span class="hlt">ENSO</span> events over the past century. The index suggests that five higher intensity (relative values 4–6) and 17 lower intensity (relative values 1–3) <span class="hlt">ENSO</span> events took place between 1910 and 1995. The <span class="hlt">ENSO</span> intensity index correlates with fluctuations in the time series of cyclone activity, precipitation, detrended sea level, wave height, sea-surface temperature, and sea-level barometric pressure. Wave height, sea level, and precipitation, which are the primary external forcing parameters in sea-cliff erosion, increase nonlinearly with increasing relative <span class="hlt">ENSO</span> event intensity. The number of storms that caused coastal erosion or storm damage and the historic occurrence of large-scale sea-cliff erosion along the central coast also increase nonlinearly with increasing relative event intensity. These correlations and the frequency distribution of relative <span class="hlt">ENSO</span> event intensities indicate that moderate- to high-intensity <span class="hlt">ENSO</span> events cause the most sea-cliff erosion and shoreline recession over the course of a century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.6334Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.6334Z"><span>Importance of convective parameterization in <span class="hlt">ENSO</span> predictions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Jieshun; Kumar, Arun; Wang, Wanqiu; Hu, Zeng-Zhen; Huang, Bohua; Balmaseda, Magdalena A.</p> <p>2017-06-01</p> <p>This letter explored the influence of atmospheric convection scheme on El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) predictions using a set of hindcast experiments. Specifically, a low-resolution version of the Climate Forecast System version 2 is used for 12 month hindcasts starting from each April during 1982-2011. The hindcast experiments are repeated with three atmospheric convection schemes. All three hindcasts apply the identical initialization with ocean initial conditions taken from the European Centre for Medium-Range Weather Forecasts and atmosphere/land initial states from the National Centers for Environmental Prediction. Assessments indicate a substantial sensitivity of the sea surface temperature prediction skill to the different convection schemes, particularly over the eastern tropical Pacific. For the Niño 3.4 index, the anomaly correlation skill can differ by 0.1-0.2 at lead times longer than 2 months. Long-term simulations are further conducted with the three convection schemes to understand the differences in prediction skill. By conducting heat budget analyses for the mixed-layer temperature anomalies, it is suggested that the convection scheme having the highest skill simulates stronger and more realistic coupled feedbacks related to <span class="hlt">ENSO</span>. Particularly, the strength of the Ekman pumping feedback is better represented, which is traced to more realistic simulation of surface wind stress. Our results imply that improving the mean state simulations in coupled (ocean-atmosphere) general circulation model (e.g., ameliorating the Intertropical Convergence Zone simulation) might further improve our <span class="hlt">ENSO</span> prediction capability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A43D0262H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A43D0262H"><span>Reforecasting the <span class="hlt">ENSO</span> Events in the Past Fifty-Seven Years (1958-2014)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, B.; Shin, C. S.; Shukla, J.; Marx, L.; Balmaseda, M.; Halder, S.; Dirmeyer, P.; Kinter, J. L.</p> <p>2016-12-01</p> <p>A set of ensemble seasonal reforecasts for 1958-2014 is conducted using the National Centers for Environmental Prediction (NCEP) Climate Forecast System, version 2 (CFSv2), initialized with observation-based ocean, atmosphere, land and sea ice reanalyses, including the Eu­ropean Centre for Medium-Range Weather Forecasts (ECMWF) global ocean reanalysis version 4, the ERA-40 atmospheric reanalysis, the NCEP CFS Reanalysis for atmosphere, land and sea ice, and the NASA Global Land Data Assimilation System reanalysis version 2.0 for land. The purpose is to examine a long and continuous seasonal reforecast dataset from a modern seasonal forecast system to be used by the research community. In comparison with other current reforecasts, this dataset allows us to evaluate the degree to which El Niño and Southern Oscillation (<span class="hlt">ENSO</span>) events can be predicted, using a larger sample of events. Furthermore, we can directly compare the predictability of the <span class="hlt">ENSO</span> events in 1960s-70s with the more widely studied <span class="hlt">ENSO</span> events occurring since the 1980s to examine the state-of-the-art seasonal forecast system's capability at different phases of global climate change and multidecadal variability. A major concern is whether the seasonal reforecasts before 1979 have useful skill when there were fewer ocean observations. Our preliminary examination of the reforecasts shows that, although the reforecasts have lower skill in predicting the SST anomalies in the North Pacific and North Atlantic before 1979, the prediction skill of the <span class="hlt">ENSO</span> onset and development for 1958-1978 is comparable to that for 1979-2014. The skill of the earlier predictions declines faster in the <span class="hlt">ENSO</span> decaying phase because the reforecasts initialized after the summer season persistently predict lingering wind and SST anomalies in the eastern equatorial Pacific during the decaying phase of several major <span class="hlt">ENSO</span> events in the 1960s-70s. Since the 1980s, the reforecasts initialized in fall overestimate the peak SST</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001939','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001939"><span>Modeling and Observations of the Response of Tropical Tropospheric Ozone to <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Waugh, D. W.; Lang, C.; Rodriquez, J. M.; Nielsen, J. E.</p> <p>2012-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of tropical variability on interannual time scales. <span class="hlt">ENSO</span> appears to extend its influence into the chemical composition of the tropical troposphere, Recent results have revealed an <span class="hlt">ENSO</span> induced wave-1 anomaly in observed tropical tropospheric column ozone, This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this result using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years, An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region, We will show targeted comparisons with SHADOZ ozonesondes over these regions to provide insight into the vertical structure. Also, comparisons with NASA's Aura satellite Microwave Limb Sounder (MLS) and Tropospheric Emissions Spectrometer (TES) instruments and other appropriate data sets will be shown. In addition, the water vapor response to <span class="hlt">ENSO</span> will be compared to help illuminate its role relative to dynamics in impacting ozone concentrations. These results indicate that the tropospheric ozone response to <span class="hlt">ENSO</span> is potentially a very useful chemistry-climate diagnostic and should be considered in future modeling assessments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170003368','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170003368"><span>Amplification of <span class="hlt">ENSO</span> Effects on Indian Summer Monsoon by Absorbing Aerosols</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Maeng-Ki; Lau, William K. M.; Kim, Kyu-Myong; Sang, Jeong; Kim, Yeon-Hee; Lee, Woo-Seop</p> <p>2015-01-01</p> <p>In this study, we present observational evidence, based on satellite aerosol measurements and MERRA reanalysis data for the period 1979-2011, indicating that absorbing aerosols can have strong influence on seasonal-to-interannual variability of the Indian summer monsoon rainfall, including amplification of <span class="hlt">ENSO</span> effects. We find a significant correlation between <span class="hlt">ENSO</span> (El Nino Southern Oscillation) and aerosol loading in April-May, with La Nina (El Nino) conditions favoring increased (decreased) aerosol accumulation over northern India, with maximum aerosol optical depth (AOD) over the Arabian Sea and Northwestern India, indicative of strong concentration of dust aerosols transported from West Asia and Middle East deserts. Composite analyses based on a normalized aerosol index (NAI) show that high concentration of aerosol over northern India in April-May is associated with increased moisture transport, enhanced dynamically induced warming of the upper troposphere over the Tibetan Plateau, and enhanced rainfall over northern India and the Himalayan foothills during May-June, followed by a subsequent suppressed monsoon rainfall over all India,consistent with the Elevated Heat Pump (EHP) hypothesis (Lau et al. 2006). Further analyses from sub-sampling of <span class="hlt">ENSO</span> years, with normal (less than 1 sigma), and abnormal (greater than 1 sigma)) NAI over northern India respectively show that the EHP may lead to an amplification of the Indian summer monsoon response to <span class="hlt">ENSO</span> forcing, particularly with respect to the increased rainfall over the Himalayan foothills, and the warming of the upper troposphere over the Tibetan Plateau. Our results suggest that absorbing aerosol, particular desert dusts can strongly modulate <span class="hlt">ENSO</span> influence, and possibly play important roles as a feedback agent in climate change in Asian monsoon regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004ClDy...22..839G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004ClDy...22..839G"><span>The preconditioning role of Tropical Atlantic Variability in the development of the <span class="hlt">ENSO</span> teleconnection: implications for the prediction of Nordeste rainfall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giannini, A.; Saravanan, R.; Chang, P.</p> <p></p> <p>A comparison of rainfall variability in the semi-arid Brazilian Nordeste in observations and in two sets of model simulations leads to the conclusion that the evolving interaction between Tropical Atlantic Variability (TAV) and the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon can explain two puzzling features of <span class="hlt">ENSO</span>'s impact on the Nordeste: (1) the event-to-event unpredictability of <span class="hlt">ENSO</span>'s impact; (2) the greater impact of cold rather than warm <span class="hlt">ENSO</span> events during the past 50 years. The explanation is in the `preconditioning' role of Tropical Atlantic Variability. When, in seasons prior to the mature phase of <span class="hlt">ENSO</span>, the tropical Atlantic happens to be evolving consistently with the development expected of the <span class="hlt">ENSO</span> teleconnection, <span class="hlt">ENSO</span> and TAV add up to force large anomalies in Nordeste rainfall. When it happens to be evolving in opposition to the canonical development of <span class="hlt">ENSO</span>, then the net outcome is less obvious, but also less anomalous. The more frequent occurrence of tropical Atlantic conditions consistent with those that develop during a cold <span class="hlt">ENSO</span> event, i.e. of a negative meridional sea surface temperature gradient, explains the weaker warm <span class="hlt">ENSO</span> and stronger cold <span class="hlt">ENSO</span> anomalies in Nordeste rainfall of the latter part of the twentieth century. Close monitoring of the evolution of the tropical Atlantic in seasons prior to the mature phase of <span class="hlt">ENSO</span> should lead to an enhanced forecast potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A23M..08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A23M..08L"><span>Tropical cyclone prediction skills - MJO and <span class="hlt">ENSO</span> dependence in S2S data sets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, C. Y.; Camargo, S.; Vitart, F.; Sobel, A. H.; Tippett, M.</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and the Madden-Julian Oscillation (MJO) are two important climate controls on tropical cyclone (TC) activity. The seasonal prediction skill of dynamical models is determined in large part by their accurate representations of the <span class="hlt">ENSO</span>-TC relationship. Regarding intraseasonal TC variability, observations suggest MJO to be the primary control. Given the ongoing effort to develop dynamical seasonal-to-subseasonal (S2S) TC predictions, it is important to examine whether the global models, running on S2S timescales, are able to reproduce these known <span class="hlt">ENSO</span>-TC and MJO-TC relationships, and how this ability affects forecasting skill. Results from the S2S project (from F. Vitart) suggest that global models have skill in predicting MJO phase with up to two weeks of lead time (four weeks for ECMWF). Meanwhile, our results show that, qualitatively speaking, the MJO-TC relationship in storm genesis is reasonably captured, with some models (e.g., ECMWF, BoM, NCEP, MetFr) performing better than the others. However, we also find that model skill in predicting basin-wide genesis and accumulated cyclone energy (ACE) are mainly due to the models' ability to capture the climatological seasonality. Removing the seasonality significantly reduces the models' skill; even the best model (ECMWF) in the most reliable basin (western north Pacific and Atlantic) has very little skill (close to 0.1 in Brier skill score for genesis and close to 0 in rank probability skill score for ACE). This brings up the question: do any factors contribute to intraseasonal TC prediction skill other than seasonality? Is the low skill, after removing the seasonality, due to poor MJO and <span class="hlt">ENSO</span> simulations, or to poor representation of other <span class="hlt">ENSO</span>-TC or MJO-TC relationships, such as <span class="hlt">ENSO</span>'s impact on the storm tracks? We will quantitatively discuss the dependence of the TC prediction skill on <span class="hlt">ENSO</span> and MJO, focusing on Western North Pacific and Atlantic, where we have sufficient</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23266700','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23266700"><span>Development of a novel robust measure for interhemispheric synchrony in the neonatal EEG: activation synchrony index (<span class="hlt">ASI</span>).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Räsänen, Okko; Metsäranta, Marjo; Vanhatalo, Sampsa</p> <p>2013-04-01</p> <p>The degree of interhemispheric synchrony in the neonatal EEG assessment refers to the co-occurrence of activity bouts during quiet sleep or burst suppression, and it has been widely considered as a key component in assessing background activity. However, no objective measures have been published for measuring it, and all conventionally used visual criteria suffer from significant ambiguities. Our present study aimed to develop such a quantitative measure of (a)synchrony, called activation synchrony index (<span class="hlt">ASI</span>). We developed the <span class="hlt">ASI</span> paradigm based on the testing of statistical independence between two quantized amplitude envelopes of wideband-filtered signals where higher frequencies had been pre-emphasized. The core parameter settings of <span class="hlt">ASI</span> paradigm were defined using a smaller EEG dataset, and the final <span class="hlt">ASI</span> paradigm was tested using a visually classified dataset of EEG records from 33 fullterm and 25 preterm babies, which showed varying grades of asynchrony. Our findings show that <span class="hlt">ASI</span> could distinguish all EEG recordings with normal synchrony from those with modest or severe asynchrony at individual level, and there was a highly significant correlation (p<0.001) between <span class="hlt">ASI</span> and the visually assessed grade of asynchrony. In addition, we showed that i) <span class="hlt">ASI</span> is stable in recordings over several hours in duration, such as the typical neonatal brain monitoring, that ii) <span class="hlt">ASI</span> values are sensitive to sleep stage, and that iii) they correlate with age in the preterm babies. Comparison of <span class="hlt">ASI</span> to other three potential paradigms demonstrated a significant competitive advantage. Finally, <span class="hlt">ASI</span> was found to be remarkably resistant to common artefacts as tested by adding significant level of real EEG artefacts from noisy recordings. An objective and reliable measure of (a)synchrony may open novel avenues for using <span class="hlt">ASI</span> as a putative early functional biomarker in the neonatal brain, as well as for building proper automated classifiers of neonatal EEG background. Notably, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2367W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2367W"><span>Changes in <span class="hlt">ENSO</span> amplitude under climate warming and cooling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yingying; Luo, Yiyong; Lu, Jian; Liu, Fukai</p> <p>2018-05-01</p> <p>The response of <span class="hlt">ENSO</span> amplitude to climate warming and cooling is investigated using the Community Earth System Model (CESM), in which the warming and cooling scenarios are designed by adding heat fluxes of equal amplitude but opposite sign onto the ocean surface, respectively. Results show that the warming induces an increase of the <span class="hlt">ENSO</span> amplitude but the cooling gives rise to a decrease of the <span class="hlt">ENSO</span> amplitude, and these changes are robust in statistics. A mixed layer heat budget analysis finds that the increasing (decreasing) SST tendency under climate warming (cooling) is mainly due to an enhancement (weakening) of dynamical feedback processes over the equatorial Pacific, including zonal advective (ZA) feedback, meridional advective (MA) feedback, thermocline (TH) feedback, and Ekman (EK) feedback. As the climate warms, a wind anomaly of the same magnitude across the equatorial Pacific can induce a stronger zonal current change in the east (i.e., a stronger ZA feedback), which in turn produces a greater weakening of upwelling (i.e., a stronger EK feedback) and thus a larger thermocline change (i.e., a stronger TH feedback). In response to the climate warming, in addition, the MA feedback is also strengthened due to an enhancement of the meridional SST gradient around the equator resulting from a weakening of the subtropical cells (STCs). It should be noted that the weakened STCs itself has a negative contribution to the change of the MA feedback which, however, appears to be secondary. And vice versa for the cooling case. Bjerknes linear stability (BJ) index is also evaluated for the linear stability of <span class="hlt">ENSO</span>, with remarkably larger (smaller) BJ index found for the warming (cooling) case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180001961','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180001961"><span><span class="hlt">ENSO</span> Related Inter-Annual Lightning Variability from the Full TRMM LIS Lightning Climatology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clark, Austin; Cecil, Daniel</p> <p>2018-01-01</p> <p>The El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) contributes to inter-annual variability of lightning production more than any other atmospheric oscillation. This study further investigated how <span class="hlt">ENSO</span> phase affects lightning production in the tropics and subtropics using the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS). Lightning data were averaged into mean annual warm, cold, and neutral 'years' for analysis of the different phases and compared to model reanalysis data. An examination of the regional sensitivities and preliminary analysis of three locations was conducted using model reanalysis data to determine the leading convective mechanisms in these areas and how they might respond to the <span class="hlt">ENSO</span> phases</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2365C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2365C"><span>The Angola Low: relationship with southern African rainfall and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crétat, Julien; Pohl, Benjamin; Dieppois, Bastien; Berthou, Ségolène; Pergaud, Julien</p> <p>2018-05-01</p> <p>The main states of the Angola Low (AL) are identified using clustering analysis applied to daily anomalous patterns of 700-hPa wind vorticity over Angola and adjacent countries from November to March for the 1980/81-2014/15 period. At the daily timescale, we examine the extent to which the main states of the AL modulate daily rainfall over southern Africa. At the interannual timescale, we assess both the relationship between the occurrence of these AL states and El Niño southern oscillation (<span class="hlt">ENSO</span>) and the role of the AL in explaining <span class="hlt">ENSO</span>'s failure in driving southern African rainfall at times. Three reanalyses are considered to account for uncertainties induced by the scarcity of data available for assimilation over southern Africa. Three preferential states of the Angola Low are identified: AL state close to its seasonal climatology with slight zonal displacements, anomalously weak AL state and anomalously strong AL state with meridional displacements. These different states all significantly modulate daily southern African rainfall. Near-climatological AL state promotes wet rainfall anomalies over eastern subtropical southern Africa and dry rainfall anomalies over its western part. A slight westward shift in the near-climatological position of the AL leads to reversed zonal gradient in rainfall. The remaining regimes significantly modulate the meridional gradient in southern African rainfall. Anomalously weak and anomalously northward AL states promote wet rainfall anomalies over tropical southern Africa and dry rainfall anomalies over subtropical southern Africa. The reverse prevails for anomalously southward AL. At the interannual timescale, <span class="hlt">ENSO</span> significantly modulates the seasonal occurrence of most AL states in the three reanalyses. Anomalously weak and southward AL states are more strongly correlated with regional rainfall than <span class="hlt">ENSO</span> in all reanalyses, suggesting that accounting for AL variability may improve seasonal forecasts. Case study analysis of the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC41B1022P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC41B1022P"><span>Biennial-Aligned Lunisolar-Forcing of <span class="hlt">ENSO</span>: Implications for Simplified Climate Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pukite, P. R.</p> <p>2017-12-01</p> <p>By solving Laplace's tidal equations along the equatorial Pacific thermocline, assuming a delayed-differential effective gravity forcing due to a combined lunar+solar (lunisolar) stimulus, we are able to precisely match <span class="hlt">ENSO</span> periodic variations over wide intervals. The underlying pattern is difficult to decode by conventional means such as spectral analysis, which is why it has remained hidden for so long, despite the excellent agreement in the time-domain. What occurs is that a non-linear seasonal modulation with monthly and fortnightly lunar impulses along with a biennially-aligned "see-saw" is enough to cause a physical aliasing and thus multiple folding in the frequency spectrum. So, instead of a conventional spectral tidal decomposition, we opted for a time-domain cross-validating approach to calibrate the amplitude and phasing of the lunisolar cycles. As the lunar forcing consists of three fundamental periods (draconic, anomalistic, synodic), we used the measured Earth's length-of-day (LOD) decomposed and resolved at a monthly time-scale [1] to align the amplitude and phase precisely. Even slight variations from the known values of the long-period tides will degrade the fit, so a high-resolution calibration is possible. Moreover, a narrow training segment from 1880-1920 using NINO34/SOI data is adequate to extrapolate the cycles of the past 100 years (see attached figure). To further understand the biennial impact of a yearly differential-delay, we were able to also decompose using difference equations the historical sea-level-height readings at Sydney harbor to clearly expose the <span class="hlt">ENSO</span> behavior. Finally, the <span class="hlt">ENSO</span> lunisolar model was validated by back-extrapolating to Unified <span class="hlt">ENSO</span> coral proxy (UEP) records dating to 1650. The quasi-biennial oscillation (QBO) behavior of equatorial stratospheric winds derives following a similar pattern to <span class="hlt">ENSO</span> via the tidal equations, but with an emphasis on draconic forcing. This improvement in <span class="hlt">ENSO</span> and QBO understanding has</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ClDy...16..393H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ClDy...16..393H"><span>Suppression of <span class="hlt">ENSO</span> in a coupled model without water vapor feedback</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hall, A.; Manabe, S.</p> <p></p> <p>We examine 800-year time series of internally generated variability in both a coupled ocean-atmosphere model where water vapor anomalies are not allowed to interact with longwave radiation and one where they are. The <span class="hlt">ENSO</span>-like phenomenon in the experiment without water vapor feedback is drastically suppressed both in amplitude and geographic extent relative to the experiment with water vapor feedback. Surprisingly, the reduced amplitude of <span class="hlt">ENSO</span>-related sea surface temperature anomalies in the model without water vapor feedback cannot be attributed to greater longwave damping of sea surface temperature. (Differences between the two experiments in radiative feedback due to clouds counterbalance almost perfectly the differences in radiative feedback due to water vapor.) Rather, the interaction between water vapor anomalies and longwave radiation affects the <span class="hlt">ENSO</span>-like phenomenon through its influence on the vertical structure of radiative heating: Because of the changes in water vapor associated with it, a given warm equatorial Pacific sea surface temperature anomaly is associated with a radiative heating profile that is much more gravitationally unstable when water vapor feedback is present. The warm sea surface temperature anomaly therefore results in more convection in the experiment with water vapor feedback. The increased convection, in turn, is related to a larger westerly wind-stress anomaly, which creates a larger decrease in upwelling of cold water, thereby enhancing the magnitude of the original warm sea surface temperature anomaly. In this manner, the interaction between water vapor anomalies and longwave radiation magnifies the air-sea interactions at the heart of the <span class="hlt">ENSO</span> phenomenon; without this interaction, the coupling between sea surface temperature and wind stress is effectively reduced, resulting in smaller amplitude <span class="hlt">ENSO</span> episodes with a more limited geographical extent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017640','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017640"><span>Comparison of Forced <span class="hlt">ENSO</span>-Like Hydrological Expressions in Simulations of the Preindustrial and Mid-Holocene</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lewis, Sophie C.; LeGrande, Allegra N.; Schmidt, Gavin A.; Kelley, Maxwell</p> <p>2014-01-01</p> <p>Using the water isotope- and vapor source distribution (VSD) tracer-enabled Goddard Institute for Space Studies ModelE-R, we examine changing El Nino-Southern Oscillation (<span class="hlt">ENSO</span>)-like expressions in the hydrological cycle in a suite of model experiments. We apply strong surface temperature anomalies associated with composite observed El Nino and La Nina events as surface boundary conditions to preindustrial and mid-Holocene model experiments in order to investigate <span class="hlt">ENSO</span>-like expressions in the hydrological cycle under varying boundary conditions. We find distinct simulated hydrological anomalies associated with El Nino-like ("ENSOWARM") and La Nina-like ("ENSOCOOL") conditions, and the region-specific VSD tracers show hydrological differences across the Pacific basin between El Nino-like and La Nina-like events. The application of ENSOCOOL forcings does not produce climatological anomalies that represent the equal but opposite impacts of the ENSOWARM experiment, as the isotopic anomalies associated with ENSOWARM conditions are generally stronger than with ENSOCOOL and the spatial patterns of change distinct. Also, when the same <span class="hlt">ENSO</span>-like surface temperature anomalies are imposed on the mid-Holocene, the hydrological response is muted, relative to the preindustrial. Mid-Holocene changes in moisture sources to the analyzed regions across the Pacific reveal potentially complex relationships between <span class="hlt">ENSO</span>-like conditions and boundary conditions. Given the complex impacts of <span class="hlt">ENSO</span>-like conditions on various aspects of the hydrological cycle, we suggest that proxy record insights into paleo-<span class="hlt">ENSO</span> variability are most likely to be robust when synthesized from a network of many spatially diverse archives, which can account for the potential nonstationarity of <span class="hlt">ENSO</span> teleconnections under different boundary conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A33N..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A33N..05G"><span><span class="hlt">ENSO</span> and its modulations on annual and multidecadal timescales revealed by Nonlinear Laplacian Spectral Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giannakis, D.; Slawinska, J. M.</p> <p>2016-12-01</p> <p>The variability of the Indo-Pacific Ocean on interannual to multidecadal timescales is investigated in a millennial control run of CCSM4 and in observations using a recently introduced technique called Nonlinear Laplacian Spectral Analysis (NLSA). Through this technique, drawbacks associated with ad hoc pre-filtering of the input data are avoided, enabling recovery of low-frequency and intermittent modes not accessible previously via classical approaches. Here, a multiscale hierarchy of modes is identified for Indo-Pacific SST and numerous linkages between these patterns are revealed. On interannual timescales, a mode with spatiotemporal pattern corresponding to the fundamental component of <span class="hlt">ENSO</span> emerges, along with modulations of the annual cycle by <span class="hlt">ENSO</span> in agreement with <span class="hlt">ENSO</span> combination mode theory. In spatiotemporal reconstructions, these patterns capture the seasonal southward migration of SST and zonal wind anomalies associated with termination of El Niño and La Niña events. Notably, this family of modes explains a significant portion of SST variance in Eastern Indian Ocean regions employed in the definition of Indian Ocean dipole (IOD) indices, suggesting that it should be useful for understanding the linkage of these indices with <span class="hlt">ENSO</span> and the interaction of the Indian and Pacific Oceans. In model data, we find that the <span class="hlt">ENSO</span> and <span class="hlt">ENSO</span> combination modes are modulated on multidecadal timescales by a mode predominantly active in the western tropical Pacific - we call this mode West Pacific Multidecadal Oscillation (WPMO). Despite the relatively low variance explained by this mode, its dynamical role appears to be significant as it has clear sign-dependent modulating relationships with the interannual modes carrying most of the variance. In particular, cold WPMO events are associated with anomalous Central Pacific westerlies favoring stronger <span class="hlt">ENSO</span> events, while warm WPMO events suppress <span class="hlt">ENSO</span> activity. Moreover, the WPMO has significant climatic impacts as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SGeo...38..277R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SGeo...38..277R"><span>Phenological Responses to <span class="hlt">ENSO</span> in the Global Oceans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Racault, M.-F.; Sathyendranath, S.; Menon, N.; Platt, T.</p> <p>2017-01-01</p> <p>Phenology relates to the study of timing of periodic events in the life cycle of plants or animals as influenced by environmental conditions and climatic forcing. Phenological metrics provide information essential to quantify variations in the life cycle of these organisms. The metrics also allow us to estimate the speed at which living organisms respond to environmental changes. At the surface of the oceans, microscopic plant cells, so-called phytoplankton, grow and sometimes form blooms, with concentrations reaching up to 100 million cells per litre and extending over many square kilometres. These blooms can have a huge collective impact on ocean colour, because they contain chlorophyll and other auxiliary pigments, making them visible from space. Phytoplankton populations have a high turnover rate and can respond within hours to days to environmental perturbations. This makes them ideal indicators to study the first-level biological response to environmental changes. In the Earth's climate system, the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) dominates large-scale inter-annual variations in environmental conditions. It serves as a natural experiment to study and understand how phytoplankton in the ocean (and hence the organisms at higher trophic levels) respond to climate variability. Here, the <span class="hlt">ENSO</span> influence on phytoplankton is estimated through variations in chlorophyll concentration, primary production and timings of initiation, peak, termination and duration of the growing period. The phenological variabilities are used to characterise phytoplankton responses to changes in some physical variables: sea surface temperature, sea surface height and wind. It is reported that in oceanic regions experiencing high annual variations in the solar cycle, such as in high latitudes, the influence of <span class="hlt">ENSO</span> may be readily measured using annual mean anomalies of physical variables. In contrast, in oceanic regions where <span class="hlt">ENSO</span> modulates a climate system characterised by a seasonal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdAtS..31..801X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdAtS..31..801X"><span>The natural oscillation of two types of <span class="hlt">ENSO</span> events based on analyses of CMIP5 model control runs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Kang; Su, Jingzhi; Zhu, Congwen</p> <p>2014-07-01</p> <p>The eastern- and central-Pacific El Niño-Southern Oscillation (EP- and CP-<span class="hlt">ENSO</span>) have been found to be dominant in the tropical Pacific Ocean, and are characterized by interannual and decadal oscillation, respectively. In the present study, we defined the EP- and CP-<span class="hlt">ENSO</span> modes by singular value decomposition (SVD) between SST and sea level pressure (SLP) anomalous fields. We evaluated the natural features of these two types of <span class="hlt">ENSO</span> modes as simulated by the pre-industrial control runs of 20 models involved in phase five of the Coupled Model Intercomparison Project (CMIP5). The results suggested that all the models show good skill in simulating the SST and SLP anomaly dipolar structures for the EP-<span class="hlt">ENSO</span> mode, but only 12 exhibit good performance in simulating the tripolar CP-<span class="hlt">ENSO</span> modes. Wavelet analysis suggested that the ensemble principal components in these 12 models exhibit an interannual and multi-decadal oscillation related to the EP- and CP-<span class="hlt">ENSO</span>, respectively. Since there are no changes in external forcing in the pre-industrial control runs, such a result implies that the decadal oscillation of CP-<span class="hlt">ENSO</span> is possibly a result of natural climate variability rather than external forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6043P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6043P"><span>The crucial role of the Green Sahara in damping <span class="hlt">ENSO</span> variability during the Holocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pausata, Francesco S. R.; Zhang, Qiong; Muschitiello, Francesco; Stager, Curt</p> <p>2016-04-01</p> <p>Several paleoclimate records show that the <span class="hlt">ENSO</span> variability may have been remarkably smaller during the mid Holocene (MH) relative to today; however, MH model simulations in which only the orbital forcing is taken into account are not able to fully capture the magnitude of this change. We use a fully coupled simulation for 6000 yr BP (MH) in which we prescribed not only the MH orbital forcing but also Saharan vegetation and reduced dust concentrations. By performing a set of idealized experiments in which each forcing is changed in turn, we show that when accounting for both vegetated Sahara and reduced dust concentrations, the amplitude of the <span class="hlt">ENSO</span> cycle and its variability are remarkably reduced (~25%) compared to case when only the orbital forcing is prescribed (only 7%). The changes in <span class="hlt">ENSO</span> behavior are accompanied by damping of the Atlantic El Niño variability (almost 50%). The simulated changes in equatorial variability are connected to the momentous strengthening of the WAM monsoon, which extents all the way to the northernmost part of the Sahara desert. Such changes in the WAM and in the atmospheric circulation over the equatorial Atlantic led to a reduction of the Atlantic El Niño variability and affect <span class="hlt">ENSO</span> behavior through the atmospheric circulation bridge between the Atlantic and the Pacific. Hence, our results suggest orbital forcing is likely not the only forcing at play behind the changes in <span class="hlt">ENSO</span> behavior and point to the changes over equatorial Atlantic connected to the Sahara greening as a crucial factor in altering the <span class="hlt">ENSO</span> spatiotemporal characteristic during the MH.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1252621-relative-contributions-mean-state-shifts-enso-driven-variability-precipitation-changes-warming-climate','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1252621-relative-contributions-mean-state-shifts-enso-driven-variability-precipitation-changes-warming-climate"><span>Relative contributions of mean-state shifts and <span class="hlt">ENSO</span>-driven variability to precipitation changes in a warming climate</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; ...</p> <p>2015-12-18</p> <p>The El Niño–Southern Oscillation (<span class="hlt">ENSO</span>) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with coupled general circulation models (CGCMs) to investigate how regional precipitation in the twenty-first century may be affected by changes in both <span class="hlt">ENSO</span>-driven precipitation variability and slowly evolving mean rainfall. First, a dominant, time-invariant pattern of canonical <span class="hlt">ENSO</span> variability (c<span class="hlt">ENSO</span>) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of twentieth-century climate change.more » Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in twenty-first-century climate projections. Models with better representation of the observed structure of the c<span class="hlt">ENSO</span> pattern produce winter rainfall teleconnection patterns that are in better accord with twentieth-century observations and more stationary during the twenty-first century. Finally, the model-predicted twenty-first-century rainfall response to c<span class="hlt">ENSO</span> is decomposed into the sum of three terms: 1) the twenty-first-century change in the mean state of precipitation, 2) the historical precipitation response to the c<span class="hlt">ENSO</span> pattern, and 3) a future enhancement in the rainfall response to c<span class="hlt">ENSO</span>, which amplifies rainfall extremes. Lastly, by examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20160000443&hterms=Change+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DChange%2Bclimate','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20160000443&hterms=Change+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DChange%2Bclimate"><span>Relative Contributions of Mean-State Shifts and <span class="hlt">ENSO</span>-Driven Variability to Precipitation Changes in a Warming Climate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; Marvel, Kate; Leung, L. Ruby; Doutriaux, Charles; Capotondi, Antonietta</p> <p>2015-01-01</p> <p>El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with coupled general circulation models (CGCMs) to investigate how regional precipitation in the twenty-first century may be affected by changes in both <span class="hlt">ENSO</span>-driven precipitation variability and slowly evolving mean rainfall. First, a dominant, time-invariant pattern of canonical <span class="hlt">ENSO</span> variability (c<span class="hlt">ENSO</span>) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of twentieth-century climate change. Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in twenty-first-century climate projections. Models with better representation of the observed structure of the c<span class="hlt">ENSO</span> pattern produce winter rainfall teleconnection patterns that are in better accord with twentieth-century observations and more stationary during the twenty-first century. Finally, the model-predicted twenty-first-century rainfall response to c<span class="hlt">ENSO</span> is decomposed into the sum of three terms: 1) the twenty-first-century change in the mean state of precipitation, 2) the historical precipitation response to the c<span class="hlt">ENSO</span> pattern, and 3) a future enhancement in the rainfall response to c<span class="hlt">ENSO</span>, which amplifies rainfall extremes. By examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150022866&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dclimate%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150022866&hterms=climate+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dclimate%2Bchange"><span>Relative Contributions of Mean-State Shifts and <span class="hlt">ENSO</span>-Driven Variability to Precipitation Changes in a Warming Climate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; Marvel, Kate; Leung, L. Ruby; Doutriaux, Charles; Capotondi, Antonietta</p> <p>2015-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with Coupled General Circulation Models (CGCMs) to investigate how regional precipitation in the 21st century may be affected by changes in both <span class="hlt">ENSO</span>-driven precipitation variability and slowly-evolving mean rainfall. First, a dominant, time-invariant pattern of canonical <span class="hlt">ENSO</span> variability (c<span class="hlt">ENSO</span>) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of 20th century climate change. Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in 21st century climate projections. Models with better representation of the observed structure of the c<span class="hlt">ENSO</span> pattern produce winter rainfall teleconnection patterns that are in better accord with 20th century observations and more stationary during the 21st century. Finally, the model-predicted 21st century rainfall response to c<span class="hlt">ENSO</span> is decomposed into the sum of three terms: 1) the 21st century change in the mean state of precipitation; 2) the historical precipitation response to the c<span class="hlt">ENSO</span> pattern; and 3) a future enhancement in the rainfall response to c<span class="hlt">ENSO</span>, which amplifies rainfall extremes. By examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.4281S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.4281S"><span>The nonstationary impact of local temperature changes and <span class="hlt">ENSO</span> on extreme precipitation at the global scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Qiaohong; Miao, Chiyuan; Qiao, Yuanyuan; Duan, Qingyun</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and local temperature are important drivers of extreme precipitation. Understanding the impact of <span class="hlt">ENSO</span> and temperature on the risk of extreme precipitation over global land will provide a foundation for risk assessment and climate-adaptive design of infrastructure in a changing climate. In this study, nonstationary generalized extreme value distributions were used to model extreme precipitation over global land for the period 1979-2015, with <span class="hlt">ENSO</span> indicator and temperature as covariates. Risk factors were estimated to quantify the contrast between the influence of different <span class="hlt">ENSO</span> phases and temperature. The results show that extreme precipitation is dominated by <span class="hlt">ENSO</span> over 22% of global land and by temperature over 26% of global land. With a warming climate, the risk of high-intensity daily extreme precipitation increases at high latitudes but decreases in tropical regions. For <span class="hlt">ENSO</span>, large parts of North America, southern South America, and southeastern and northeastern China are shown to suffer greater risk in El Niño years, with more than double the chance of intense extreme precipitation in El Niño years compared with La Niña years. Moreover, regions with more intense precipitation are more sensitive to <span class="hlt">ENSO</span>. Global climate models were used to investigate the changing relationship between extreme precipitation and the covariates. The risk of extreme, high-intensity precipitation increases across high latitudes of the Northern Hemisphere but decreases in middle and lower latitudes under a warming climate scenario, and will likely trigger increases in severe flooding and droughts across the globe. However, there is some uncertainties associated with the influence of <span class="hlt">ENSO</span> on predictions of future extreme precipitation, with the spatial extent and risk varying among the different models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A43I..03L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A43I..03L"><span>Influence of <span class="hlt">ENSO</span> on Gulf Stream cyclogenesis and the North Atlantic storm track</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, C.; Schemm, S.; Ciasto, L.; Kvamsto, N. G.</p> <p>2015-12-01</p> <p>There is emerging evidence that climate in the North Atlantic-European sector is sensitive to vacillations of tropical Pacific sea surface temperatures, in particular, the central Pacific flavour of the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) and concomitant trends in atmospheric heating. The frequency of central Pacific <span class="hlt">ENSOs</span> appears to have increased over the last decades and some studies suggest it may continue increasing in the future, but the precise mechanisms by which these events affect the North Atlantic synoptic scale circulation are poorly understood. Here, we show that central Pacific <span class="hlt">ENSOs</span> influence where midlatitude cyclogenesis occurs over the Gulf Stream, producing more cyclogenesis in the jet exit region rather than in the climatologically preferred jet entrance region. The cyclones forming over the Gulf Stream in central Pacific <span class="hlt">ENSO</span> seasons tend to veer north, penetrating deeper into the Arctic rather than into continental Europe. The shift in cyclogenesis is linked to changes in the large scale circulation, namely, the upper-level trough formed in the lee of the Rocky Mountains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4265694','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4265694"><span>Characteristics of Lake Chad Level Variability and Links to <span class="hlt">ENSO</span>, Precipitation, and River Discharge</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Demoz, Belay; Gebremariam, Sium</p> <p>2014-01-01</p> <p>This study used trend, correlation, and wavelet analysis to characterize Lake Chad (LC) level fluctuations, river discharge, El Niño Southern Oscillation (<span class="hlt">ENSO</span>), and precipitation regimes and their interrelationships. Linear correlation results indicate a negative association between <span class="hlt">ENSO</span> and LC level, river discharge and precipitation. Trend analysis shows increasing precipitation in the Lake Chad Basin (LCB) but decreasing LC level. The mode of interannual variability in LC level, rainfall, and <span class="hlt">ENSO</span> analyzed using wavelet analysis is dominated by 3-4-year periods. Results show that variability in <span class="hlt">ENSO</span> could explain only 31% and 13% of variations in LC level at Kindjeria and precipitation in the northern LCB, respectively. The wavelet transform coherency (WTC) between LC level of the southern pool at Kalom and <span class="hlt">ENSO</span> is statistically significant at the 95% confidence level and phase-locked, implying a cause-and-effect association. These strong coherencies coincide with the La Niña years with the exception of 1997-1998 El Niño events. The WTC shows strong covariance between increasing precipitation and LC level in the northern pool at a 2- to 4-year band and 3- to 4-year band localized from 1996 to 2010. Implications for water resource planning and management are discussed. PMID:25538946</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29720617','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29720617"><span>Modulation of the relationship between spring AO and the subsequent winter <span class="hlt">ENSO</span> by the preceding November AO.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Shangfeng; Chen, Wen; Yu, Bin</p> <p>2018-05-02</p> <p>Previous studies indicated that the spring Arctic Oscillation (AO) exerts significant influences on the subsequent winter El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). This analysis suggests that the spring AO-<span class="hlt">ENSO</span> linkage is highly modulated by its preceding November AO. When November and the subsequent spring AO indices are in phase, the spring AO has a pronounced influence on <span class="hlt">ENSO</span>. However, when the November and spring AO indices are out of phase, the spring AO-<span class="hlt">ENSO</span> connection disappears. Modulation of the November AO on the spring AO-<span class="hlt">ENSO</span> connection is mainly through the constructive and destructive superposition of the November and spring AO associated sea surface temperature (SST) anomalies in the tropical central-eastern Pacific in spring and summer, as well as the SST anomalies developed further in the tropical Pacific via the positive air-sea feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdAtS..34..360Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdAtS..34..360Q"><span>Relationships between the extratropical <span class="hlt">ENSO</span> precursor and leading modes of atmospheric variability in the Southern Hemisphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Jianhuang; Ding, Ruiqiang; Wu, Zhiwei; Li, Jianping; Zhao, Sen</p> <p>2017-03-01</p> <p>Previous studies suggest that the atmospheric precursor of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) in the extratropical Southern Hemisphere (SH) might trigger a quadrapole sea surface temperature anomaly (SSTA) in the South Pacific and subsequently influence the following <span class="hlt">ENSO</span>. Such a quadrapole SSTA is referred to as the South Pacific quadrapole (SPQ). The present study investigated the relationships between the atmospheric precursor signal of <span class="hlt">ENSO</span> and leading modes of atmospheric variability in the extratropical SH [including the SH annular mode (SAM), the first Pacific-South America (PSA1) mode, and the second Pacific-South America (PSA2) mode]. The results showed that the atmospheric precursor signal in the extratropical SH basically exhibits a barotropic wavenumber-3 structure over the South Pacific and is significantly correlated with the SAM and the PSA2 mode during austral summer. Nevertheless, only the PSA2 mode was found to be a precursor for the following <span class="hlt">ENSO</span>. It leads the SPQ-like SSTA by around one month, while the SAM and the PSA1 mode do not show any obvious linkage with either <span class="hlt">ENSO</span> or the SPQ. This suggests that the PSA2 mode may provide a bridge between the preceding circulation anomalies over the extratropical SH and the following <span class="hlt">ENSO</span> through the SPQ-like SSTA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122..279D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122..279D"><span>Joint impact of North and South Pacific extratropical atmospheric variability on the onset of <span class="hlt">ENSO</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, Ruiqiang; Li, Jianping; Tseng, Yu-heng; Sun, Cheng; Xie, Fei</p> <p>2017-01-01</p> <p>Previous studies have indicated that boreal winter subtropical and extratropical sea surface pressure (SLP) anomalies over both the North and South Pacific are significantly related to the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) state in the following boreal winter. Here we use observational data and model simulations to show that the ability of the boreal winter North Pacific SLP anomalies to initiate <span class="hlt">ENSO</span> events a year later may strongly depend on the state of the simultaneous South Pacific SLP anomalies and vice versa. When the boreal winter North Pacific SLP anomalies are of the opposite sign to the simultaneous South Pacific anomalies, the correlation of the North or South Pacific anomalies with the following <span class="hlt">ENSO</span> state becomes much weaker, and the strength of the <span class="hlt">ENSO</span> events also tends to be weaker. One possible reason for this is that when the boreal winter North and South Pacific SLP anomalies have the opposite sign, the westerly anomalies over the western-central equatorial Pacific during the following boreal summer are greatly reduced by the interference between the antecedent North and South Pacific SLP anomalies, thereby not favoring the development of <span class="hlt">ENSO</span> events. Further analysis indicates that a combination of North and South Pacific precursor signals may serve to enhance the <span class="hlt">ENSO</span> prediction skill.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40.2284B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40.2284B"><span>Kawasaki disease and <span class="hlt">ENSO</span>-driven wind circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ballester, Joan; Burns, Jane C.; Cayan, Dan; Nakamura, Yosikazu; Uehara, Ritei; Rodó, Xavier</p> <p>2013-05-01</p> <p>disease (KD) is the most common cause of acquired heart disease in children worldwide. Recently, a climatological study suggested that KD may be triggered by a windborne agent traveling across the north Pacific through the westerly wind flow prevailing at midlatitudes. Here we use KD records to describe the association between enhanced disease activity on opposite sides of the basin and different phases of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon, via the linkage to these tropospheric winds. Results show that years with higher-than-normal KD cases in Japan preferentially occur during either El Niño Modoki or La Niña conditions, while in San Diego during the mature phase of El Niño or La Niña events. Given that <span class="hlt">ENSO</span> offers a degree of predictability at lead times of 6 months, these modulations suggest that seasonal predictions of KD could be used to alert clinicians to periods of increased disease activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2396G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2396G"><span>Linear dynamical modes as new variables for data-driven <span class="hlt">ENSO</span> forecast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gavrilov, Andrey; Seleznev, Aleksei; Mukhin, Dmitry; Loskutov, Evgeny; Feigin, Alexander; Kurths, Juergen</p> <p>2018-05-01</p> <p>A new data-driven model for analysis and prediction of spatially distributed time series is proposed. The model is based on a linear dynamical mode (LDM) decomposition of the observed data which is derived from a recently developed nonlinear dimensionality reduction approach. The key point of this approach is its ability to take into account simple dynamical properties of the observed system by means of revealing the system's dominant time scales. The LDMs are used as new variables for empirical construction of a nonlinear stochastic evolution operator. The method is applied to the sea surface temperature anomaly field in the tropical belt where the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) is the main mode of variability. The advantage of LDMs versus traditionally used empirical orthogonal function decomposition is demonstrated for this data. Specifically, it is shown that the new model has a competitive <span class="hlt">ENSO</span> forecast skill in comparison with the other existing <span class="hlt">ENSO</span> models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8313E..3FV','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8313E..3FV"><span>Quantitative evaluation of <span class="hlt">ASi</span>R image quality: an adaptive statistical iterative reconstruction technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van de Casteele, Elke; Parizel, Paul; Sijbers, Jan</p> <p>2012-03-01</p> <p>Adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R) is a new reconstruction algorithm used in the field of medical X-ray imaging. This new reconstruction method combines the idealized system representation, as we know it from the standard Filtered Back Projection (FBP) algorithm, and the strength of iterative reconstruction by including a noise model in the reconstruction scheme. It studies how noise propagates through the reconstruction steps, feeds this model back into the loop and iteratively reduces noise in the reconstructed image without affecting spatial resolution. In this paper the effect of <span class="hlt">ASi</span>R on the contrast to noise ratio is studied using the low contrast module of the Catphan phantom. The experiments were done on a GE LightSpeed VCT system at different voltages and currents. The results show reduced noise and increased contrast for the <span class="hlt">ASi</span>R reconstructions compared to the standard FBP method. For the same contrast to noise ratio the images from <span class="hlt">ASi</span>R can be obtained using 60% less current, leading to a reduction in dose of the same amount.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ThApC.127..259M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ThApC.127..259M"><span>Improved predictability of droughts over southern Africa using the standardized precipitation evapotranspiration index and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manatsa, Desmond; Mushore, Terrence; Lenouo, Andre</p> <p>2017-01-01</p> <p>The provision of timely and reliable climate information on which to base management decisions remains a critical component in drought planning for southern Africa. In this observational study, we have not only proposed a forecasting scheme which caters for timeliness and reliability but improved relevance of the climate information by using a novel drought index called the standardised precipitation evapotranspiration index (SPEI), instead of the traditional precipitation only based index, the standardised precipitation index (SPI). The SPEI which includes temperature and other climatic factors in its construction has a more robust connection to <span class="hlt">ENSO</span> than the SPI. Consequently, the developed <span class="hlt">ENSO</span>-SPEI prediction scheme can provide quantitative information about the spatial extent and severity of predicted drought conditions in a way that reflects more closely the level of risk in the global warming context of the sub region. However, it is established that the <span class="hlt">ENSO</span> significant regional impact is restricted only to the period December-March, implying a revisit to the traditional <span class="hlt">ENSO</span>-based forecast scheme which essentially divides the rainfall season into the two periods, October to December and January to March. Although the prediction of <span class="hlt">ENSO</span> events has increased with the refinement of numerical models, this work has demonstrated that the prediction of drought impacts related to <span class="hlt">ENSO</span> is also a reality based only on observations. A large temporal lag is observed between the development of <span class="hlt">ENSO</span> phenomena (typically in May of the previous year) and the identification of regional SPEI defined drought conditions. It has been shown that using the Southern Africa Regional Climate Outlook Forum's (SARCOF) traditional 3-month averaged Nino 3.4 SST index (June to August) as a predictor does not have an added advantage over using only the May SST index values. In this regard, the extended lead time and improved skill demonstrated in this study could immensely benefit</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2661091','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2661091"><span>The role of <span class="hlt">ENSO</span> in understanding changes in Colombia's annual malaria burden by region, 1960–2006</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mantilla, Gilma; Oliveros, Hugo; Barnston, Anthony G</p> <p>2009-01-01</p> <p>Background Malaria remains a serious problem in Colombia. The number of malaria cases is governed by multiple climatic and non-climatic factors. Malaria control policies, and climate controls such as rainfall and temperature variations associated with the El Niño/Southern Oscillation (<span class="hlt">ENSO</span>), have been associated with malaria case numbers. Using historical climate data and annual malaria case number data from 1960 to 2006, statistical models are developed to isolate the effects of climate in each of Colombia's five contrasting geographical regions. Methods Because year to year climate variability associated with <span class="hlt">ENSO</span> causes interannual variability in malaria case numbers, while changes in population and institutional control policy result in more gradual trends, the chosen predictors in the models are annual indices of the <span class="hlt">ENSO</span> state (sea surface temperature [SST] in the tropical Pacific Ocean) and time reference indices keyed to two major malaria trends during the study period. Two models were used: a Poisson and a Negative Binomial regression model. Two <span class="hlt">ENSO</span> indices, two time reference indices, and one dummy variable are chosen as candidate predictors. The analysis was conducted using the five geographical regions to match the similar aggregation used by the National Institute of Health for its official reports. Results The Negative Binomial regression model is found better suited to the malaria cases in Colombia. Both the trend variables and the <span class="hlt">ENSO</span> measures are significant predictors of malaria case numbers in Colombia as a whole, and in two of the five regions. A one degree Celsius change in SST (indicating a weak to moderate <span class="hlt">ENSO</span> event) is seen to translate to an approximate 20% increase in malaria cases, holding other variables constant. Conclusion Regional differentiation in the role of <span class="hlt">ENSO</span> in understanding changes in Colombia's annual malaria burden during 1960–2006 was found, constituting a new approach to use <span class="hlt">ENSO</span> as a significant predictor of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170004582','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170004582"><span>The Impact of <span class="hlt">ENSO</span> on Trace Gas Composition in the Upper Troposphere to Lower Stratosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, Luke; Douglass, Anne; Ziemke, Jerry; Waugh, Darryn Warwick</p> <p>2016-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of interannual variability in the tropical troposphere and its effects extend well into the stratosphere. Its impact on atmospheric dynamics and chemistry cause important changes to trace gas constituent distributions. A comprehensive suite of satellite observations, reanalyses, and chemistry climate model simulations are illuminating our understanding of processes like <span class="hlt">ENSO</span>. Analyses of more than a decade of observations from NASAs Aura and Aqua satellites, combined with simulations from the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) and other Chemistry Climate Modeling Initiative (CCMI) models, and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) reanalysis have provided key insights into the response of atmospheric composition to <span class="hlt">ENSO</span>. While we will primarily focus on ozone and water vapor responses in the upper troposphere to lower stratosphere, the effects of <span class="hlt">ENSO</span> ripple through many important trace gas species throughout the atmosphere. The very large 2015-2016 El Nino event provides an opportunity to closely examine these impacts with unprecedented observational breadth. An improved quantification of natural climate variations, like those from <span class="hlt">ENSO</span>, is needed to detect and quantify anthropogenic climate changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A43D0268P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A43D0268P"><span>A Spatial Perspective of Droughts and Pluvials in the Tropics and their Relationships to <span class="hlt">ENSO</span> in CMIP5 Model Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez Arango, J. D.; Lintner, B. R.; Lyon, B.</p> <p>2016-12-01</p> <p>Although many aspects of the tropical response to <span class="hlt">ENSO</span> are well-known, the spatial characteristics of the rainfall response to <span class="hlt">ENSO</span> remain relatively unexplored. Moreover, in current generation climate models, the spatial signatures of the <span class="hlt">ENSO</span> tropical teleconnection are more uncertain than other aspects of <span class="hlt">ENSO</span> variability, such as the amplitude of rainfall anomalies. Following the approach of Lyon (2004) and Lyon and Barnston (2005), we analyze here integrated measures of the spatial extent of drought and pluvial conditions in the tropics and their relationship to <span class="hlt">ENSO</span> in observations as well as simulations of Phase 5 of the Coupled Model Intercomparison Project (CMIP5) with prescribed SST forcing. We compute diagnostics including the model ensemble-means and standard deviations of moderate, intermediate, and severe droughts and pluvials and the lagged correlations with respect to <span class="hlt">ENSO</span>-based SST indices like NINO3. Overall, in a tropics-wide sense, the models generally capture the areal extent of observed droughts and pluvials and their phasing with respect to <span class="hlt">ENSO</span>. However, at more local scales, e.g., tropical South America, the simulated metrics agree less strongly with observations, underscoring the role of errors in the spatial patterns of <span class="hlt">ENSO</span>-induced rainfall anomalies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683514','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683514"><span><span class="hlt">ENSO</span> Modulations due to Interannual Variability of Freshwater Forcing and Ocean Biology-induced Heating in the Tropical Pacific</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Rong-Hua; Gao, Chuan; Kang, Xianbiao; Zhi, Hai; Wang, Zhanggui; Feng, Licheng</p> <p>2015-01-01</p> <p>Recent studies have identified clear climate feedbacks associated with interannual variations in freshwater forcing (FWF) and ocean biology-induced heating (OBH) in the tropical Pacific. The interrelationships among the related anomaly fields are analyzed using hybrid coupled model (HCM) simulations to illustrate their combined roles in modulating the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). The HCM-based supporting experiments are performed to isolate the related feedbacks, with interannually varying FWF and OBH being represented individually or collectively, which allows their effects to be examined in a clear way. It is demonstrated that the interannual freshwater forcing enhances <span class="hlt">ENSO</span> variability and slightly prolongs the simulated <span class="hlt">ENSO</span> period, while the interannual OBH reduces <span class="hlt">ENSO</span> variability and slightly shortens the <span class="hlt">ENSO</span> period, with their feedback effects tending to counteract each other. PMID:26678931</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA......310C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA......310C"><span>The <span class="hlt">enso</span> signal in the lower stratosphere: propagation via rossby waves.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calvo, N.; Garcia Herrera, R.; Garcia, R.; Gallego, D.; Gimeno, L.; Hernandez, E.; Ribera, P.</p> <p>2003-04-01</p> <p>The <span class="hlt">ENSO</span> signal on the lower stratosphere has been analyzed through the study of the relationship between SST in the Tropical Pacific and lower stratospheric temperatures from the Microwave Sounding Unit (MSU) using the t4 channel, which is sensitive to lower stratospheric temperature. Lagged point correlations have been calculated between the Niño3.4 index and MSU t4 monthly anomaly series at each grid point for the whole globe from January 1979 through December 2000. Correlation values are very similar in both tropics and extratropics, but their signs are opposite: positive in extratropical regions and negative in the tropics. Moreover, the significant correlation signal is longer lasting at middle latitudes, from lag 9 to lag 6, and much shorter in the Tropics, where it is significant only at lags 0 and 3. In the extratropical area, four regions are significant: Eurasia, the Southern Indian Ocean, and the North and South Pacific Oceans. The signal in Eurasia is the first to be observed (at lag 9) and it could be considered as a predictor of extreme <span class="hlt">ENSO</span> events. The Pacific Ocean shows the PNA and PSA patterns. There, the signal appears earlier in the Southern Hemisphere (lag 6) because wind conditions at boreal summer (usually lag 6) do not favour the propagation of Rossby waves into the stratosphere. Further, the shape of the correlation patterns suggests that only planetary waves are able to propagate the <span class="hlt">ENSO</span> signal into the stratosphere. In the tropics, the <span class="hlt">ENSO</span> signal takes the form of a pair of Rossby gyres, observed in the Pacific Ocean at lags 0 and 3 as two regions of significant correlation located symmetricaly north and south of the Equator. The same analysis has been carried out for a period without any extreme events (SST anomalies in the Niño3.4 region smaller than 1 standard desviation), in which case no signal is observed in the lower stratosphere. This suggests that only strong <span class="hlt">ENSO</span> (defined by anomalies larger than 1 standard desviation in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991JCli....4..743A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991JCli....4..743A"><span>A Further Extension of the Tahiti-Darwin SOI, Early <span class="hlt">ENSO</span> Events and Darwin Pressure.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allan, Robert J.; Nicholls, Neville; Jones, Phil D.; Butterworth, Ian J.</p> <p>1991-07-01</p> <p>An extension of the Tahiti minus Darwin Southern Oscillation Index (SOI) from 1882 back to 1876 is reported following the recovery of early Darwin mean sea-level pressure data spanning the period 1865-81. As a result, we are able to compare, for the first time, the major 1877-78 and 1982-83 <span class="hlt">ENSO</span> events on the basis of this commonly used index. Early Darwin and Jakarta data are also examined in terms of a measure of the Australian response to documented El Niño and/or <span class="hlt">ENSO</span> events in 1866, 1868, 1871, 1873, 1874 and 1875.The SOI during the 1877-78 <span class="hlt">ENSO</span> event has a similar temporal response to that in 1982-83, but the index is slightly weaker than in the recent event. Examination of documentary evidence confirms the severity of the drought conditions that affected the Australian continent during the 1877-78 <span class="hlt">ENSO</span>, and shows that this response is in line with the wider Indo-Pacific impacts reported in the literature. Earlier El Niño phases in 1868 and 1873 are not resolved distinctly in either the Darwin or Jakarta pressure data. This appears to illustrate that El Niño event histories do not always indicate wider <span class="hlt">ENSO</span> influences in the Indo-Pacific basin, particularly during weak to moderate phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.4019Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.4019Z"><span>Response of <span class="hlt">ENSO</span> amplitude to global warming in CESM large ensemble: uncertainty due to internal variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Xiao-Tong; Hui, Chang; Yeh, Sang-Wook</p> <p>2018-06-01</p> <p>El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of variability in the coupled ocean-atmospheric system. Future projections of <span class="hlt">ENSO</span> change under global warming are highly uncertain among models. In this study, the effect of internal variability on <span class="hlt">ENSO</span> amplitude change in future climate projections is investigated based on a 40-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. A large uncertainty is identified among ensemble members due to internal variability. The inter-member diversity is associated with a zonal dipole pattern of sea surface temperature (SST) change in the mean along the equator, which is similar to the second empirical orthogonal function (EOF) mode of tropical Pacific decadal variability (TPDV) in the unforced control simulation. The uncertainty in CESM-LE is comparable in magnitude to that among models of the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting the contribution of internal variability to the intermodel uncertainty in <span class="hlt">ENSO</span> amplitude change. However, the causations between changes in <span class="hlt">ENSO</span> amplitude and the mean state are distinct between CESM-LE and CMIP5 ensemble. The CESM-LE results indicate that a large ensemble of 15 members is needed to separate the relative contributions to <span class="hlt">ENSO</span> amplitude change over the twenty-first century between forced response and internal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011840','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011840"><span><span class="hlt">ENSO</span> Effect on East Asian Tropical Cyclone Landfall via Changes in Tracks and Genesis in a Statistical Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yonekura, Emmi; Hall, Timothy M.</p> <p>2014-01-01</p> <p>Improvements on a statistical tropical cyclone (TC) track model in the western North Pacific Ocean are described. The goal of the model is to study the effect of El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) on East Asian TC landfall. The model is based on the International Best-Track Archive for Climate Stewardship (IBTrACS) database of TC observations for 1945-2007 and employs local regression of TC formation rates and track increments on the Nino-3.4 index and seasonally varying climate parameters. The main improvements are the inclusion of <span class="hlt">ENSO</span> dependence in the track propagation and accounting for seasonality in both genesis and tracks. A comparison of simulations of the 1945-2007 period with observations concludes that the model updates improve the skill of this model in simulating TCs. Changes in TC genesis and tracks are analyzed separately and cumulatively in simulations of stationary extreme <span class="hlt">ENSO</span> states. <span class="hlt">ENSO</span> effects on regional (100-km scale) landfall are attributed to changes in genesis and tracks. The effect of <span class="hlt">ENSO</span> on genesis is predominantly a shift in genesis location from the southeast in El Nino years to the northwest in La Nina years, resulting in higher landfall rates for the East Asian coast during La Nina. The effect of <span class="hlt">ENSO</span> on track propagation varies seasonally and spatially. In the peak activity season (July-October), there are significant changes in mean tracks with <span class="hlt">ENSO</span>. Landfall-rate changes from genesis- and track-<span class="hlt">ENSO</span> effects in the Philippines cancel out, while coastal segments of Vietnam, China, the Korean Peninsula, and Japan show enhanced La Nina-year increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..139a2020D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..139a2020D"><span>The impact of <span class="hlt">ENSO</span> on regional chlorophyll-a anomaly in the Arafura Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dewi, D. M. P. R.; Fatmasari, D.; Kurniawan, A.; Munandar, M. A.</p> <p>2018-03-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is a naturally occurring phenomenon that involves fluctuating ocean temperature in the equatorial Pacific. <span class="hlt">ENSO</span> influences ocean climate variability in Indonesia including the Arafura Sea. The relationship between oceanic chlorophyll-a and <span class="hlt">ENSO</span> has been the focus of study over the past decade. Here we examine the impact of <span class="hlt">ENSO</span> on regional chlorophyll-a anomaly in the Papua waters using 14 years of chlorophyll-a and sea surface temperature (SST) data from AQUA MODIS and sea level anomaly data from AVISO. It is found that when El Niño events occur the negative SST anomaly in the Papua waters as well as the enhanced upwelling cause the increase of chlorophyll-a concentration. The highest chlorophyll-a concentration (> 1 mg–cm-3) occured during El Niño and observed around the Aru archipelago. In contrast during La Niña event, the positive SST anomaly in Papua waters and the suppressed upwelling cause the decrease of chlorophyll-a concentration. Our results suggest that during El Niño (La Niña), the enhanced (suppressed) upwelling related to the significant decreasing (increasing) of sea level anomaly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC53A1256V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC53A1256V"><span>Development of a global Agricultural Stress Index System (<span class="hlt">ASIS</span>) based on remote sensing data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van Hoolst, R.</p> <p>2016-12-01</p> <p>According to the 2012 IPCC SREX report, extreme drought events are projected to become more frequent and intense in several regions of the world. Wide and timely monitoring systems are required to mitigate the impact of agricultural drought. Therefore, FAO's Global Information and Early Warning System (GIEWS) and the Climate, Energy and Tenure Division (NRC) have established the `Agricultural Stress Index System' (<span class="hlt">ASIS</span>). The <span class="hlt">ASIS</span> is a remote sensing application that provides early warnings of agricultural drought at a global scale. The <span class="hlt">ASIS</span> has first been designed and described by Rojas et al. (2011). This study focused on the African continent and was based on the back processing of low resolution data of the NOAA-satellites. In the current setup, developed by VITO (Flemish Institute for Technological Research), the system operates in Near Real Time using data from the METOP-AVHRR sensor. The Agricultural Stress Index (<span class="hlt">ASI</span>) is the percentage of agricultural area affected by drought in the course of the growing season within a given administrative unit. The start and end of the growing season are derived per pixel from the long term NDVI average of SPOT-VEGETATION. The Global Administrative Unit Layer (GAUL) defines the administrative boundaries at level 0, 1 and 2. A global cropland and grassland map eliminates non-agricultural areas. Temperature and NDVI anomalies are used as drought indicators and calculated at a per pixel base. The <span class="hlt">ASIS</span> aggregates this information and produces every dekad global maps to highlight hotspots of drought stress. New developments are ongoing to strengthen the <span class="hlt">ASIS</span> to produce country specific outputs, improve existing drought indicators and estimate production deficits using a probabilistic approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP31D2324C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP31D2324C"><span>Connection between <span class="hlt">ENSO</span> and Asian Summer Monsoon Precipitation Oxygen Isotope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Z.; Tian, L.</p> <p>2016-12-01</p> <p>In an effort to understand the connection between El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and Asian Summer Monsoon (ASM) precipitation oxygen isotope, this study investigates the spatial and interannual patterns in summer (JJAS) monsoon precipitation δ18O and satellite water vapor isotope retrievals, especially those patterns associated with convection and vapor transport. Both precipitation and vapor isotope values exhibit a "V" shaped longitudinal pattern in their spatial variations, reflecting the gradual rainout and increase in convective intensity along vapor transport routes. In order to understand interannual variations, an ASM precipitation δ18O index (ASMOI) is introduced to measure the temporal variations in regional precipitation δ18O; and these variations are consistent with central Indo-Pacific convection and cloud-top height. The counter variations in the ASMOI in El Niño and La Niña years confirm the existence of a positive isotope- <span class="hlt">ENSO</span> response (e.g., high values corresponding to warm phases) over the eastern Indian Ocean and southeastern Asia (80°E-120°E/10°S-30°N) as a response to changes in convection. However, JJAS vapor δD over the western Pacific (roughly east of 120oE) varies in opposition, due to the influence of water vapor transport. This opposite variation does not support the interpretation of precipitation isotope-<span class="hlt">ENSO</span> relationship as changing proportion of vapor transported from different regions, but rather condensation processes associated with convection. These findings are important for studying past ASM and <span class="hlt">ENSO</span> activity from various isotopic archives and have implications for the study of the atmospheric water cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918230T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918230T"><span>The role of sea surface salinity in <span class="hlt">ENSO</span> related water cycle anomaly</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Wenqing; Yueh, Simon</p> <p>2017-04-01</p> <p>This study investigates the role of sea surface salinity (SSS) in the water cycle anomaly associated with El Niño Southern Oscillation (<span class="hlt">ENSO</span>). The 2015-16 El Niño, one of the strongest <span class="hlt">ENSO</span> events observed in centuries, coincident with unprecedented coverage of spacebased remote sensing of SSS over global oceans. We analyze three SSS data sets: from the NASA's missions of SMAP and Aquarius, and the ESA's Soil Moisture and Ocean Salinity (SMOS). One typical characteristics of an <span class="hlt">ENSO</span> event is the zonal displacement of the Western equatorial Pacific Fresh Pool (WPFP). The edge of the pool extends eastward during El Niño, retreats westward during La Niña. For super El Niño, the eastern edge of WPFP extends much more east across the equatorial Pacific. Indeed, SSS from SMAP reveals much stronger eastward migration of WPFP starting in April 2015. The eastern edge of WPFP reached 140°W in March 2016, about 40° more eastward extension than Aquarius observed in previous years. In the following months from March to June 2016, WPFP retreated westward, coincident with the ending of this strong El Niño event [WMO, El Nino/La Nina update, 2016]. SMOS data shows similar feature, confirming that there is no systematic biases between SMAP and Aquarius retrievals. We examine the linkage between the observed SSS variation and <span class="hlt">ENSO</span> related water cycle anomaly by integrated analysis of SSS data sets in conjunction with other satellite and in situ measurements on rain, wind, evaporation and ocean currents. Based on the governing equation of the mixed layer salt budget, the freshwater exchange between air-sea interfaces is estimated as residual of the mixed-layer salinity (MLS) temporal change and advection (Focean), as an alternative to evaporation minus precipitation (FE-P). We analyzed the spatial and temporal variation of Focean and FE-P to explore the anomalous signature in the oceanic and atmospheric branches of the water cycle associated with 2015/16 <span class="hlt">ENSO</span>. The maximum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMGC51A0457K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMGC51A0457K"><span><span class="hlt">ENSO</span>-Based Index Insurance: Approach and Peru Flood Risk Management Application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khalil, A. F.; Kwon, H.; Lall, U.; Miranda, M. J.; Skees, J. R.</p> <p>2006-12-01</p> <p>Index insurance has recently been advocated as a useful risk transfer tool for disaster management situations where rapid fiscal relief is desirable, and where estimating insured losses may be difficult, time consuming, or subject to manipulation and falsification. For climate related hazards, a rainfall or temperature index may be proposed. However, rainfall may be highly spatially variable relative to the gauge network, and in many locations data are inadequate to develop an index due to short time-series and the spatial dispersion of stations. In such cases, it may be helpful to consider a climate proxy index as a regional rainfall index. This is particularly useful if a long record is available for the climate index through an independent source and it is well correlated with the regional rainfall hazard. Here, <span class="hlt">ENSO</span> related climate indices are explored for use as a proxy to extreme rainfall in one of the departments of Peru -- Piura. The <span class="hlt">ENSO</span> index insurance product may be purchased by banks or microfinance institutions (MFIs) to aid agricultural damage relief in Peru. Crop losses in the region are highly correlated with floods, but are difficult to assess directly. Beyond agriculture, many other sectors suffer as well. Basic infrastructure is destroyed during the most severe events. This disrupts trade for many micro-enterprises. The reliability and quality of the local rainfall data is variable. Averaging the financial risk across the region is desirable. Some issues with the implementation of the proxy <span class="hlt">ENSO</span> index are identified and discussed. Specifically, we explore (a) the reliability of the index at different levels of probability of exceedance of maximum seasonal rainfall; (b) the potential for clustering of payoffs; (c) the potential that the index could be predicted with some lead time prior to the flood season; and (d) evidence for climate change or non-stationarity in the flood exceedance probability from the long <span class="hlt">ENSO</span> record. Finally, prospects for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdAtS..31...66L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdAtS..31...66L"><span>The interdecadal changes of south pacific sea surface temperature in the mid-1990s and their connections with <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Gang; Li, Chongyin; Tan, Yanke; Bai, Tao</p> <p>2014-01-01</p> <p>The characteristic changes of South Pacific sea surface temperature anomalies (SSTAs) for the period January 1979 to December 2011, during which the 1990s Pacific pan-decadal variability (PDV) interdecadal regime shifts occurred, were examined. Empirical Orthogonal Function (EOF) analysis was applied to the monthly mean SSTA for two sub-periods: January 1979 to December 1994 (P1) and January 1996 to December 2011 (P2). Both the spatial and temporal features of the leading EOF mode for P1 and P2 showed a remarkable difference. The spatial structure of the leading EOF changed from a tripolar pattern for P1 (EOF-P1) to a dipole-like pattern for P2 (EOF-P2). Besides, EOF-P1 (EOF-P2) had significant spectral peaks at 4.6 yr (2.7 yr). EOF-P2 not only had a closer association with El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), but also showed a faster response to <span class="hlt">ENSO</span> than EOF-P1 based on their lead-lag relationships with <span class="hlt">ENSO</span>. During the development of <span class="hlt">ENSO</span>, the South Pacific SSTA associated with <span class="hlt">ENSO</span> for both P1 and P2 showed a significant eastward propagation. However, after the peak of <span class="hlt">ENSO</span>, EOF-P1 showed a stronger persistence than EOF-P2, which still showed eastward propagation. The variability of the SSTA associated with the whole process of <span class="hlt">ENSO</span> evolution during P1 and the SSTA associated with the development of <span class="hlt">ENSO</span> during P2 support the existence of ocean-to-atmosphere forcing, but the SSTA associated with the decay of <span class="hlt">ENSO</span> shows the phenomenon of atmosphere-to-ocean forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H13O..04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H13O..04M"><span>Influence of <span class="hlt">ENSO</span> on coastal flood hazard and exposure at the global-scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muis, S.; Haigh, I. D.; Guimarães Nobre, G.; Aerts, J.; Ward, P.</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant signal of interannual climate variability. The unusually warm (El Niño) and cold (La Niña) oceanic and atmospheric conditions in the tropical Pacific drives interannual variability in both mean and extreme sea levels, which in turn may influence the probabilities and impacts of coastal flooding. We assess the influence of <span class="hlt">ENSO</span> on coastal flood hazard and exposure using daily timeseries from the Global Time and Surge Reanalysis (GTSR) dataset (Muis et al., 2016). As the GTSR timeseries do not include steric effects (i.e. density differences), we improve the GTSR timeseries by adding steric sea levels. Evaluation against observed sea levels shows that the including steric sea levels leads to a much better representation of the seasonal and interannual variability. We show that sea level anomalies occur during <span class="hlt">ENSO</span> years with higher sea levels during La Niña in the South-Atlantic, Indian Ocean and the West Pacific, whereas sea levels are lower in the east Pacific. The pattern is generally inversed for El Niño. We also find an effect of <span class="hlt">ENSO</span> in the number of people exposed to coastal flooding. Although the effect is minor at the global-scale, it may be important for flood risk management to consider at the national or sub national levels. Previous studies at the global-scale have used tide gauge observation to assess the influence of <span class="hlt">ENSO</span> on extreme sea levels. The advantage of our approach over observations is that GTSR provides a consistent dataset with a full global coverage for the period 1979-2014. This allows us to assess <span class="hlt">ENSO</span>'s influence on sea level extremes anywhere in the world. Furthermore, it enables us to also calculate the impacts of extreme sea levels in terms of coastal flooding and exposed population. ReferencesMuis et al (2016) A global reanalysis of storm surges and extreme sea levels. Nature Communications.7:11969. doi:10.1038/ncomms11969.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5354B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5354B"><span>HadCM3 Simulations of <span class="hlt">ENSO</span> behaviour during the Mid-Pliocene Warm Period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonham, S. G.; Haywood, A. M.; Lunt, D. J.</p> <p>2009-04-01</p> <p>It has been suggested that a permanent El Niño state existed during the mid-Pliocene (ca. 3.3 - 3.0 Ma BP), with a west-to-east temperature gradient in the tropical Pacific considerably weaker than today. This is based upon a number of palaeoceanographic studies which have examined the development of the thermocline and SST gradient in the tropical Pacific over the last five million years. This state is now being referred to as El Padre in recognition of the fact that a mean state warming in EEP SSTs does not necessarily imply the presence of a permanent El Niño. Recent results from mid-Pliocene coupled ocean-atmosphere model simulations have shown clear <span class="hlt">ENSO</span> variability whilst maintaining the warming in the EEP. This research expands on this study, using the UK Met Office GCM (HadCM3), to examine the behaviour and characteristics of <span class="hlt">ENSO</span> in two mid-Pliocene simulations (with an open and closed Central American Seaway, CAS) compared with a control pre-industrial run, as well as produce a detailed profile of the mean state climates. The results shown include timescales of <span class="hlt">ENSO</span> variability across four regions in the Pacific, as well as frequency, EOF and wavelet analysis. We have also looked at the interaction of <span class="hlt">ENSO</span> with the annual cycle and the onset of <span class="hlt">ENSO</span> events, and the interdecadal variability in the simulations. The initial timeseries produced have shown a greater variability of <span class="hlt">ENSO</span> during the closed CAS mid-Pliocene simulation where the system oscillates between events much more frequently than seen in the pre-industrial run. The EOF and wavelet analyses quantify this behaviour, showing that the variability is approximately 15% higher over the central and eastern equatorial Pacific, with a period of oscillation of 2-5 years compared with 4-8 years for the pre-industrial simulation. These results will be compared with those obtained from the second mid-Pliocene simulation (open CAS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.2558A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.2558A"><span><span class="hlt">ENSO</span> relationship to Summer Rainfall Variability and its Potential Predictability over Arabian Peninsula Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adnan Abid, Mohammad; Almazroui, Mansour; Kucharski, Fred</p> <p>2017-04-01</p> <p>Summer seasonal rainfall falls mainly over the south and southwestern parts of the Arabian Peninsula (AP). The relationship between this mean summer seasonal rainfall pattern and El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is analyzed with the aid of a 15-member ensemble of simulations using the King Abdulaziz University (KAU) Atmospheric Global Climate Model (AGCM). Each simulation is forced with Hadley Sea Surface Temperature (SST) for the period 1980-2015. The southwestern peninsula rainfall is linked towith the SST anomalies in the central-eastern pacific region. This relation is established through an atmospheric teleconnection which shows an upper-level convergence (divergence) anomalies over the southern Arabian Peninsula compensating the central-eastern Pacific region upper-level divergence (convergence) anomalies for the warm (cold) El Niño Southern Oscillaton (<span class="hlt">ENSO</span>) phase. The upper-level convergence (divergence) over the southern Arabian Peninsula leads to sinking (rising) motion, low-level divergence (convergence) and consequently to reduced (enhanced) rainfall. The correlation coefficient between the observed area-averged Niño3.4 index and athe South Arabian Rainfall Index (SARI) is -0.54. This indicates that AP receives less rainfall during the warm (El Niño) phase, while the opposite happens in the cold (La Niña) El Niño Southern Oscillaton (<span class="hlt">ENSO</span>) phase. The lower tropospheric cyclonic circulation anomalies strongly modulate the <span class="hlt">ENSO</span>-related rainfall in the region. Overall, the model shows a 43% potential predictability (PP) for the Southern Arabian Peninsula Rainfall Index (SARI). Further, the predictability during the warm <span class="hlt">ENSO</span> (El Niño) events is higher than during cold <span class="hlt">ENSO</span> (La Niña) events. This is not only because of a stronger signal, but also noise reduction contributes to the increase of the regional PP in El Niño compared to that of La Niña years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150008896&hterms=Logistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLogistics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150008896&hterms=Logistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLogistics"><span>Dual Use of <span class="hlt">Packaging</span> on the Moon: Logistics-2-Living</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Howe, A. Scott; Howard, Robert</p> <p>2010-01-01</p> <p>This paper describes a modular <span class="hlt">packaging</span> system for logistics that can be reconfigured into internal outfitting for a lunar outpost, including desks, chairs, partitions, cabinets, and radiation shielding. Logistics include clothes, equipment, food, and other consumables needed to sustain the crew for the duration of the mission. A significant mass penalty is required for the <span class="hlt">packaging</span> and handling of logistics for re-supply of short to long-term space missions that must be brought out of the gravity well on a launch vehicle. Once the supplies have been exhausted, the <span class="hlt">packaging</span> material is typically of no further use and is discarded. If a scheme can be developed that reuses the logistics <span class="hlt">packaging</span>, the mass penalty can be reduced. In this research, a modular <span class="hlt">packaging</span> system has been devised as a kit-of-parts that can be used for both handling logistics supplies, and then reconfigured into desks, chairs, partitions, cabinets, and radiation shielding. The system is derived from a standard International Space Station (ISS)-type Cargo Transfer Bag (CTB), using soft, unfoldable box-like containers with stiff metal inserts. The empty hydrogen-impregnated CTBs can be used <span class="hlt">as-is</span> for cabinets, opened up for use as partitions, or draped over the habitat as layers of radiation shielding. Stiff metal inserts can be reconfigured into desks and other useful outfitting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp.2384E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp.2384E"><span>Future changes in rainfall associated with <span class="hlt">ENSO</span>, IOD and changes in the mean state over Eastern Africa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Endris, Hussen Seid; Lennard, Christopher; Hewitson, Bruce; Dosio, Alessandro; Nikulin, Grigory; Artan, Guleid A.</p> <p>2018-05-01</p> <p>This study examines the projected changes in the characteristics of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and Indian Ocean Dipole (IOD) in terms of mean state, intensity and frequency, and associated rainfall anomalies over eastern Africa. Two regional climate models driven by the same four global climate models (GCMs) and the corresponding GCM simulations are used to investigate projected changes in teleconnection patterns and East African rainfall. The period 1976-2005 is taken as the reference for present climate and the far-future climate (2070-2099) under Representative Concentration Pathway 8.5 (RCP8.5) is analyzed for projected change. Analyses of projections based on GCMs indicate an El Niño-like (positive IOD-like) warming pattern over the tropical Pacific (Indian) Ocean. However, large uncertainties remain in the projected future changes in <span class="hlt">ENSO</span>/IOD frequency and intensity with some GCMs show increase of <span class="hlt">ENSO</span>/IOD frequency and intensity, and others a decrease or no/small change. Projected changes in mean rainfall over eastern Africa based on the GCM and RCM data indicate a decrease in rainfall over most parts of the region during JJAS and MAM seasons, and an increase in rainfall over equatorial and southern part of the region during OND, with the greatest changes in equatorial region. During <span class="hlt">ENSO</span> and IOD years, important changes in the strength of the teleconnections are found. During JJAS, when <span class="hlt">ENSO</span> is an important driver of rainfall variability over the region, both GCM and RCM projections show an enhanced La Niña-related rainfall anomaly compared to the present period. Although the long rains (MAM) have little association with <span class="hlt">ENSO</span> in the reference period, both GCMs and RCMs project stronger <span class="hlt">ENSO</span> teleconnections in the future. On the other hand, during the short rains (OND), a dipole future change in rainfall teleconnection associated with <span class="hlt">ENSO</span> and IOD is found, with a stronger <span class="hlt">ENSO</span>/IOD related rainfall anomaly over the eastern part of the domain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1617208','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1617208"><span>Marine lake ecosystem dynamics illustrate <span class="hlt">ENSO</span> variation in the tropical western Pacific</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Martin, Laura E; Dawson, Michael N; Bell, Lori J; Colin, Patrick L</p> <p>2005-01-01</p> <p>Understanding El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled <span class="hlt">ENSO</span>-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Niña than El Niño conditions, temperature anomalies in the lake co-vary strongly with the Niño 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an <span class="hlt">ENSO</span> signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian–zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting <span class="hlt">ENSO</span> responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response. PMID:17148349</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17148349','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17148349"><span>Marine lake ecosystem dynamics illustrate <span class="hlt">ENSO</span> variation in the tropical western Pacific.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martin, Laura E; Dawson, Michael N; Bell, Lori J; Colin, Patrick L</p> <p>2006-03-22</p> <p>Understanding El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) and its biological consequences is hindered by a lack of high-resolution, long-term data from the tropical western Pacific. We describe a preliminary, 6 year dataset that shows tightly coupled <span class="hlt">ENSO</span>-related bio-physical dynamics in a seawater lake in Palau, Micronesia. The lake is more strongly stratified during La Niña than El Niño conditions, temperature anomalies in the lake co-vary strongly with the Niño 3.4 climate index, and the abundance of the dominant member of the pelagic community, an endemic subspecies of zooxanthellate jellyfish, is temperature associated. These results have broad relevance because the lake: (i) illustrates an <span class="hlt">ENSO</span> signal that is partly obscured in surrounding semi-enclosed lagoon waters and, therefore, (ii) may provide a model system for studying the effects of climate change on community evolution and cnidarian-zooxanthellae symbioses, which (iii) should be traceable throughout the Holocene because the lake harbours a high quality sediment record; the sediment record should (iv) provide a sensitive and regionally unique record of Holocene climate relevant to predicting <span class="hlt">ENSO</span> responses to future global climate change and, finally, (v) seawater lake ecosystems elsewhere in the Pacific may hold similar potential for past, present, and predictive measurements of climate variation and ecosystem response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JCrGr.362..149O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JCrGr.362..149O"><span>Liquid-phase explosive crystallization of electron-beam-evaporated <span class="hlt">a-Si</span> films induced by flash lamp annealing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohdaira, Keisuke; Matsumura, Hideki</p> <p>2013-01-01</p> <p>We succeed in the formation of micrometer-order-thick polycrystalline silicon (poly-Si) films through the flash-lamp-induced liquid-phase explosive crystallization (EC) of precursor <span class="hlt">a-Si</span> films prepared by electron-beam (EB) evaporation. The velocity of the explosive crystallization (vEC) is estimated to be ˜14 m/s, which is close to the velocity of the liquid-phase epitaxy (LPE) of Si at a temperature around the melting point of <span class="hlt">a-Si</span> of 1418 K. Poly-Si films formed have micrometer-order-long grains stretched along a lateral crystallization direction, and X-ray diffraction (XRD) and electron diffraction pattern measurements reveal that grains in poly-Si films tend to have a particular orientation. These features are significantly different from our previous results: the formation of poly-Si films containing randomly-oriented 10-nm-sized fine grains formed from <span class="hlt">a-Si</span> films prepared by catalytic chemical vapor deposition (Cat-CVD) or sputtering. One possible reason for the emergence of a different EC mode in EB-evaporated <span class="hlt">a-Si</span> films is the suppression of solid-phase nucleation (SPN) during Flash Lamp Annealing (FLA) due to tensile stress which precursor <span class="hlt">a-Si</span> films originally hold. Poly-Si films formed from EB-evaporated <span class="hlt">a-Si</span> films would contribute to the realization of high-efficiency thin-film poly-Si solar cells because of large and oriented grains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1392324-schemaonread-package-schema-read','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1392324-schemaonread-package-schema-read"><span>SchemaOnRead: A <span class="hlt">Package</span> for Schema-on-Read in R</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>North, Michael J.</p> <p></p> <p>Schema-on-read is an agile approach to data storage and retrieval that defers investments in data organization until production queries need to be run by working with data directly in native form. Schema-on-read functions have been implemented in a wide range of analytical systems, most notably Hadoop. SchemaOnRead is a CRAN <span class="hlt">package</span> that uses R’s flexible data representations to provide transparent and convenient support for the schema-on-read paradigm in R. The schema-on- read tools within the <span class="hlt">package</span> include a single function call that recursively reads folders with text, comma separated value, raster image, R data, HDF5, NetCDF, spreadsheet, Weka, Epi Info,more » Pajek network, R network, HTML, SPSS, Systat, and Stata files. The provided tools can be used <span class="hlt">as-is</span> or easily adapted to implement customized schema-on-read tool chains in R. This paper’s contribution is that it introduces and describes SchemaOnRead, the first R <span class="hlt">package</span> specifically focused on providing explicit schema-on-read support in R.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1518H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1518H"><span>Role of 20th tropical precipitation on <span class="hlt">ENSO</span> amplitude changes due to greenhouse warming in CMIP5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ham, Yoo-Geun; Kug, Jong-Seong</p> <p>2016-04-01</p> <p>This study examines the relationship between the intermodel diversities of the present-climate climatology and those of <span class="hlt">ENSO</span> amplitude change under global warming in the Coupled Model Intercomparison Project phase 5 (CMIP5) models. The models with increased <span class="hlt">ENSO</span> amplitude under greenhouse warming (i.e., '<span class="hlt">ENSO</span>-amplified models') tend to simulate a 20th century stronger climatological ITCZ and SPCZ over the central-eastern Pacific that are located further away from the equator during boreal spring. Moisture budget analysis indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which leads to increase the <span class="hlt">ENSO</span> amplitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRD..123..198S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRD..123..198S"><span>Modulation of Winter Precipitation Dynamics Over the Arabian Gulf by <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sandeep, S.; Ajayamohan, R. S.</p> <p>2018-01-01</p> <p>The Arabian Gulf (Gulf) and the surrounding regions are centers of intense economic activity. The precipitating weather systems that form over the Gulf are important for this predominantly arid region. It is suggested that El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) influences the Middle East precipitation variability through an equatorward shift of the subtropical jet. Here we present compelling evidence to illustrate the role of <span class="hlt">ENSO</span> in modulating the local dynamics and moisture transport in initiating precipitation during different <span class="hlt">ENSO</span> phases using satellite and reanalysis data. It is found that the moisture transport from the Red and Arabian Seas toward the Gulf is stronger during El Niño years. The pattern and strength of moisture transport toward the Gulf is weakened during La Niña and neutral years, with most of the transport directed toward the northern Gulf. Using a 120 h back trajectory analysis, it is found that while the air parcels coming toward the Gulf from the Arabian and Red Seas side originate at lower tropospheric levels, the air parcels from the Mediterranean originate at middle and upper tropospheric levels during El Niño years. In contrast, upper tropospheric air parcels originating over the southern Arabian Sea plays a dominant role on Gulf precipitation during La Niña and neutral years. The seasonal mean transients of zonal winds show a robust <span class="hlt">ENSO</span> signature over the Gulf, indicating a favorable (less favorable) condition for the penetration of midlatitude eddies over the region during El Niño (La Niña) winters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8453P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8453P"><span><span class="hlt">ENSO</span> detection and use to inform the operation of large scale water systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pham, Vuong; Giuliani, Matteo; Castelletti, Andrea</p> <p>2016-04-01</p> <p>El Nino Southern Oscillation (<span class="hlt">ENSO</span>) is a large-scale, coupled ocean-atmosphere phenomenon occurring in the tropical Pacific Ocean, and is considered one of the most significant factors causing hydro-climatic anomalies throughout the world. Water systems operations could benefit from a better understanding of this global phenomenon, which has the potential for enhancing the accuracy and lead-time of long-range streamflow predictions. In turn, these are key to design interannual water transfers in large scale water systems to contrast increasingly frequent extremes induced by changing climate. Despite the <span class="hlt">ENSO</span> teleconnection is well defined in some locations such as Western USA and Australia, there is no consensus on how it can be detected and used in other river basins, particularly in Europe, Africa, and Asia. In this work, we contribute a general framework relying on Input Variable Selection techniques for detecting <span class="hlt">ENSO</span> teleconnection and using this information for improving water reservoir operations. Core of our procedure is the Iterative Input variable Selection (IIS) algorithm, which is employed to find the most relevant determinants of streamflow variability for deriving predictive models based on the selected inputs as well as to find the most valuable information for conditioning operating decisions. Our framework is applied to the multipurpose operations of the Hoa Binh reservoir in the Red River basin (Vietnam), taking into account hydropower production, water supply for irrigation, and flood mitigation during the monsoon season. Numerical results show that our framework is able to quantify the relationship between the <span class="hlt">ENSO</span> fluctuations and the Red River basin hydrology. Moreover, we demonstrate that such <span class="hlt">ENSO</span> teleconnection represents valuable information for improving the operations of Hoa Binh reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.2537W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.2537W"><span>Effect of AMOC collapse on <span class="hlt">ENSO</span> in a high resolution general circulation model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williamson, Mark S.; Collins, Mat; Drijfhout, Sybren S.; Kahana, Ron; Mecking, Jennifer V.; Lenton, Timothy M.</p> <p>2018-04-01</p> <p>We look at changes in the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) in a high-resolution eddy-permitting climate model experiment in which the Atlantic Meridional Circulation (AMOC) is switched off using freshwater hosing. The <span class="hlt">ENSO</span> mode is shifted eastward and its period becomes longer and more regular when the AMOC is off. The eastward shift can be attributed to an anomalous eastern Ekman transport in the mean equatorial Pacific ocean state. Convergence of this transport deepens the thermocline in the eastern tropical Pacific and increases the temperature anomaly relaxation time, causing increased <span class="hlt">ENSO</span> period. The anomalous Ekman transport is caused by a surface northerly wind anomaly in response to the meridional sea surface temperature dipole that results from switching the AMOC off. In contrast to a previous study with an earlier version of the model, which showed an increase in <span class="hlt">ENSO</span> amplitude in an AMOC off experiment, here the amplitude remains the same as in the AMOC on control state. We attribute this difference to variations in the response of decreased stochastic forcing in the different models, which competes with the reduced damping of temperature anomalies. In the new high-resolution model, these effects approximately cancel resulting in no change in amplitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.132..727M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.132..727M"><span><span class="hlt">ENSO</span> shifts and their link to Southern Africa surface air temperature in summer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manatsa, D.; Mukwada, G.; Makaba, L.</p> <p>2018-05-01</p> <p><span class="hlt">ENSO</span> has been known to influence the trends of summer warming over Southern Africa. In this work, we used observational and reanalysis data to analyze the relationship between <span class="hlt">ENSO</span> and maximum surface air temperature (SATmax) trends during the three epochs created by the <span class="hlt">ENSO</span> phase shifts around 1977 and 1997 for the period 1960 to 2014. We observed that while <span class="hlt">ENSO</span> and cloud cover remains the dominant factor controlling SATmax variability, the first two epochs had the predominant La Niña (El Niño)-like events connected to robust positive (negative) trends in cloud fraction. However, this established relationship reversed in the post-1997 La Niña-like dominated epoch which coincided with a falling cloud cover trend. It is established that this deviation from the previously established link within the previous epochs could be due to the post-1998 era in which SATmin was suppressed while SATmax was enhanced. The resulting increase in diurnal temperature range (DTR) could have discouraged the formation of low-level clouds which have relatively more extensive areal coverage and hence allowing more solar energy to reach the surface to boost daytime SATmax. It is noted that these relationships are more pronounced from December to March.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B21G2046D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B21G2046D"><span>Tree Carbohydrate Dynamics Across a Rainfall Gradient in Panama During the 2016 <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dickman, L. T.; Xu, C.; Behar, H.; McDowell, N.</p> <p>2017-12-01</p> <p>Non-structural carbohydrates (NSC) provide a measure of the carbon supply available to support respiration, growth, and defense. Support for a role of carbon starvation - or depletion of NSC stores - in drought induced tree mortality is varied without consensus for the tropics. The 2016 <span class="hlt">ENSO</span> drought provided a unique opportunity to capture drought impacts on tropical forest carbohydrate dynamics. To quantify these impacts, we collected monthly NSC samples across a rainfall gradient in Panama for the duration of the <span class="hlt">ENSO</span>. We observed high variability in foliar NSC among species within sites. Foliage contained very little starch, indicating that total NSC dynamics are driven by soluble sugars. Foliar NSC depletion did not progress with drought duration as predicted, but showed little variation over course of the <span class="hlt">ENSO</span>. Foliar NSC did, however, increase with rainfall, suggesting NSC depletion may occur with longer-term drought. These results suggest that, while short-term droughts like the 2016 <span class="hlt">ENSO</span> may not have a significant impact on carbon dynamics, we may observe greater impacts as drought progresses over longer timescales. These results will be used to evaluate whether the current implementation of carbon starvation in climate models are capturing observed trends in tropical forest carbon allocation and mortality, and to tune model parameters for improved predictive capability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18..604S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18..604S"><span>Empirical modeling <span class="hlt">ENSO</span> dynamics with complex-valued artificial neural networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seleznev, Aleksei; Gavrilov, Andrey; Mukhin, Dmitry</p> <p>2016-04-01</p> <p>The main difficulty in empirical reconstructing the distributed dynamical systems (e.g. regional climate systems, such as El-Nino-Southern Oscillation - <span class="hlt">ENSO</span>) is a huge amount of observational data comprising time-varying spatial fields of several variables. An efficient reduction of system's dimensionality thereby is essential for inferring an evolution operator (EO) for a low-dimensional subsystem that determines the key properties of the observed dynamics. In this work, to efficient reduction of observational data sets we use complex-valued (Hilbert) empirical orthogonal functions which are appropriate, by their nature, for describing propagating structures unlike traditional empirical orthogonal functions. For the approximation of the EO, a universal model in the form of complex-valued artificial neural network is suggested. The effectiveness of this approach is demonstrated by predicting both the Jin-Neelin-Ghil <span class="hlt">ENSO</span> model [1] behavior and real <span class="hlt">ENSO</span> variability from sea surface temperature anomalies data [2]. The study is supported by Government of Russian Federation (agreement #14.Z50.31.0033 with the Institute of Applied Physics of RAS). 1. Jin, F.-F., J. D. Neelin, and M. Ghil, 1996: El Ni˜no/Southern Oscillation and the annual cycle: subharmonic frequency locking and aperiodicity. Physica D, 98, 442-465. 2. http://iridl.ldeo.columbia.edu/SOURCES/.KAPLAN/.EXTENDED/.v2/.ssta/</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45..327G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45..327G"><span>A New Method for Interpreting Nonstationary Running Correlations and Its Application to the <span class="hlt">ENSO</span>-EAWM Relationship</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geng, Xin; Zhang, Wenjun; Jin, Fei-Fei; Stuecker, Malte F.</p> <p>2018-01-01</p> <p>We here propose a new statistical method to interpret nonstationary running correlations by decomposing them into a stationary part and a first-order Taylor expansion approximation for the nonstationary part. Then, this method is applied to investigate the nonstationary behavior of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>)-East Asian winter monsoon (EAWM) relationship, which exhibits prominent multidecadal variations. It is demonstrated that the first-order approximation of the nonstationary part can be expressed to a large extent by the impact of the nonlinear interaction between the Atlantic Multidecadal Oscillation (AMO) and <span class="hlt">ENSO</span> (AMO*Niño3.4) on the EAWM. Therefore, the nonstationarity in the <span class="hlt">ENSO</span>-EAWM relationship comes predominantly from the impact of an AMO modulation on the <span class="hlt">ENSO</span>-EAWM teleconnection via this key nonlinear interaction. This general method can be applied to investigate nonstationary relationships that are often observed between various different climate phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009842','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009842"><span>The Response of Tropospheric Ozone to <span class="hlt">ENSO</span> in Observations and a Chemistry-Climate Simulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Waugh, D. W.; Rodriguez, J. M.; Nielsen, J. E.</p> <p>2012-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of tropical variability on interannual time scales. <span class="hlt">ENSO</span> appears to extend its influence into the chemical composition of the tropical troposphere. Recent results have revealed an <span class="hlt">ENSO</span> induced wave-l anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this result using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show targeted comparisons with observations from NASA's Aura satellite Microwave Limb Sounder (MLS), and the Tropospheric Emissions Spectrometer (TES) to provide insight into the vertical structure of ozone changes. The tropospheric ozone response to <span class="hlt">ENSO</span> could be a useful chemistry-climate model evaluation tool and should be considered in future modeling assessments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdAtS..35..671F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdAtS..35..671F"><span>Simulating Eastern- and Central-Pacific Type <span class="hlt">ENSO</span> Using a Simple Coupled Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Xianghui; Zheng, Fei</p> <p>2018-06-01</p> <p>Severe biases exist in state-of-the-art general circulation models (GCMs) in capturing realistic central-Pacific (CP) El Niño structures. At the same time, many observational analyses have emphasized that thermocline (TH) feedback and zonal advective (ZA) feedback play dominant roles in the development of eastern-Pacific (EP) and CP El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), respectively. In this work, a simple linear air-sea coupled model, which can accurately depict the strength distribution of the TH and ZA feedbacks in the equatorial Pacific, is used to investigate these two types of El Niño. The results indicate that the model can reproduce the main characteristics of CP <span class="hlt">ENSO</span> if the TH feedback is switched off and the ZA feedback is retained as the only positive feedback, confirming the dominant role played by ZA feedback in the development of CP <span class="hlt">ENSO</span>. Further experiments indicate that, through a simple nonlinear control approach, many <span class="hlt">ENSO</span> characteristics, including the existence of both CP and EP El Niño and the asymmetries between El Niño and La Niña, can be successfully captured using the simple linear air-sea coupled model. These analyses indicate that an accurate depiction of the climatological sea surface temperature distribution and the related ZA feedback, which are the subject of severe biases in GCMs, is very important in simulating a realistic CP El Niño.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49..249H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49..249H"><span>The weakening of the <span class="hlt">ENSO</span>-Indian Ocean Dipole (IOD) coupling strength in recent decades</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ham, Yoo-Geun; Choi, Jun-Young; Kug, Jong-Seong</p> <p>2017-07-01</p> <p>This study examines a recent weakening of the coupling between the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) and the Indian Ocean Dipole (IOD) mode after the 2000s and 2010s compared to the previous two decades (1980s and 1990s). The correlation between the IOD during the September-November season and the Nino3.4 index during the December-February season is 0.21 for 1999-2014, while for the previous two decades (1979-1998) it is 0.64. It is found that this weakening of the <span class="hlt">ENSO</span>-IOD coupling during the 2000s and 2010s is associated with different spatial patterns in <span class="hlt">ENSO</span> evolution during the boreal spring and summer seasons. During the boreal spring season of the El Nino developing phase, positive precipitation anomalies over the northern off-equatorial western Pacific is systematically weakened during the 2000s and 2010s. This also weakens the low-level cross-equatorial southerly flow, which can cause local negative precipitation anomalies over the maritime continent through increased evaporation and cold and dry moist energy advection. The weakened negative precipitation anomalies over the maritime continent reduces the amplitude of the equatorial easterly over the IO, therefore, suppresses a <span class="hlt">ENSO</span>-related IOD variability. An analysis using climate models that participated in the Coupled Model Intercomparison Project phase 5 (CMIP5) supports this observational findings that the amplitude of the cross-equatorial southerly flow and associated suppressed convective activities over the maritime continent during the El Nino developing season are critical for determining the <span class="hlt">ENSO</span>-IOD coupling strength in climate models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A51O0297X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A51O0297X"><span>Is <span class="hlt">ENSO</span> related to 2015 Easter Star Capsized on the Yangtze River of China?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, P.</p> <p>2015-12-01</p> <p>Natural disasters have profound effects on community security and economic damage of China's Hubei province. In June 1st, 2015, a cruise ship, Easter Star, capsized on Yangtze River in Hubei province with 442 died. What reason gives rise to such strong convection causing ship sunk? Based on the wind disasters of Hubei province happened in 1963-2015, this study analyzes their features bytime-series regression, and correlates them to global El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) events. The compared results demonstrated that the wind disasters shown an increasing tendency. There are two peaks corresponding to the strongest <span class="hlt">ENSO</span> peaks during the past 50 years; each peak lasts two-three years. The facts demonstrated an essential linear relation between the <span class="hlt">ENSO</span> phenomena and wind disasters in Hubei province. 2015 Easter Star capsized happened at current El Niño event in 2014-2015. We also observed that the historical wind disasters appeared in seasonal variation. Over 90% events concentrated in spring and summer; very few events happened in autumn and winter. Moreover, the disasters depend on the geographic conditions. Most disasters concentrated in four zones, named as Xingshan-Baokang, Xuanen, Wufeng-Yichang, Jingzhou-Gongan, in which Xingshan and Changyang are the two most density of zones. Yangtze River provides an air flowing conduct for strong convective winds. It can be concluded that the strong convection causing 2015 Easter Star capsized is related to current global <span class="hlt">ENSO</span> phenomenon.Keywords: <span class="hlt">ENSO</span>, wind disaster, time-series regression analysis, Easter Star, Yangtze River, Hubei Province,</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy..tmp..246T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy..tmp..246T"><span>Assessing probabilistic predictions of <span class="hlt">ENSO</span> phase and intensity from the North American Multimodel Ensemble</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tippett, Michael K.; Ranganathan, Meghana; L'Heureux, Michelle; Barnston, Anthony G.; DelSole, Timothy</p> <p>2017-05-01</p> <p>Here we examine the skill of three, five, and seven-category monthly <span class="hlt">ENSO</span> probability forecasts (1982-2015) from single and multi-model ensemble integrations of the North American Multimodel Ensemble (NMME) project. Three-category forecasts are typical and provide probabilities for the <span class="hlt">ENSO</span> phase (El Niño, La Niña or neutral). Additional forecast categories indicate the likelihood of <span class="hlt">ENSO</span> conditions being weak, moderate or strong. The level of skill observed for differing numbers of forecast categories can help to determine the appropriate degree of forecast precision. However, the dependence of the skill score itself on the number of forecast categories must be taken into account. For reliable forecasts with same quality, the ranked probability skill score (RPSS) is fairly insensitive to the number of categories, while the logarithmic skill score (LSS) is an information measure and increases as categories are added. The ignorance skill score decreases to zero as forecast categories are added, regardless of skill level. For all models, forecast formats and skill scores, the northern spring predictability barrier explains much of the dependence of skill on target month and forecast lead. RPSS values for monthly <span class="hlt">ENSO</span> forecasts show little dependence on the number of categories. However, the LSS of multimodel ensemble forecasts with five and seven categories show statistically significant advantages over the three-category forecasts for the targets and leads that are least affected by the spring predictability barrier. These findings indicate that current prediction systems are capable of providing more detailed probabilistic forecasts of <span class="hlt">ENSO</span> phase and amplitude than are typically provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000115609','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000115609"><span>Characteristics of the East Asian Winter Climate Associated with the Westerly Jet Stream and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yang, Song; Lau, K.-M.; Kim, K.-M.; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>In this study, the influences of the East Asian jet stream (EAJS) and El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) on the interannual variability of the East Asian winter climate are examined with a focus on the relative climate impacts of the two phenomena. Although the variations of the East Asian winter monsoon and the temperature and precipitation of China, Japan, and Korea are emphasized, the associated changes in the broad-scale atmospheric circulation patterns over Asia and the Pacific and in the extratropical North Pacific sea surface temperature (SST) are also investigated. It is demonstrated that there is no apparent relationship between <span class="hlt">ENSO</span> and the interannual variability of EAJS core. The EAJS and <span class="hlt">ENSO</span> are associated with distinctly different patterns of atmospheric circulation and SST in the Asian-Pacific regions. While <span class="hlt">ENSO</span> causes major climate signals in the Tropics and over the North Pacific east of the dateline, the EAJS produces significant changes in the atmospheric circulation over East Asia and western Pacific. In particular, the EAJS explains larger variance of the interannual signals of the East Asian trough, the Asian continental high, the Aleutian low, and the East Asian winter monsoon. When the EAJS is strong, all these atmospheric systems intensify significantly. The response of surface temperature and precipitation to EAJS variability and <span class="hlt">ENSO</span> is more complex. In general, the East Asian winter climate is cold (warm) and dry (wet) when the EAJS is strong (weak) and it is warm during El Nino years. However, different climate signals are found during different La Nina years. In terms of linear correlation, both the temperature and precipitation of northern China, Korea, and central Japan are more significantly associated with the EAJS than with <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010CliPa...6..401C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010CliPa...6..401C"><span>Coral Cd/Ca and Mn/Ca records of <span class="hlt">ENSO</span> variability in the Gulf of California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carriquiry, J. D.; Villaescusa, J. A.</p> <p>2010-06-01</p> <p>We analyzed the trace element ratios Cd/Ca and Mn/Ca in three coral colonies (Porites panamensis (1967-1989), Pavona clivosa (1967-1989) and Pavona gigantea (1979-1989)) from Cabo Pulmo reef, Southern Gulf of California, Mexico, to assess the oceanographic changes caused by El Niño - Southern Oscillation (<span class="hlt">ENSO</span>) events in the Eastern Tropical North Pacific (ETNP). Interannual variations in the coral Cd/Ca and Mn/Ca ratios showed clear evidence that incorporation of Cd and Mn in the coral skeleton was influenced by <span class="hlt">ENSO</span> conditions, but the response for each metal was controlled by different processes. The Mn/Ca ratios were significantly higher during <span class="hlt">ENSO</span> years (p<0.05) relative to non-<span class="hlt">ENSO</span> years for the three species of coral. In contrast, the Cd/Ca was systematically lower during <span class="hlt">ENSO</span> years, but the difference was significant (p<0.05) only in Pavona gigantea. A decrease in the incorporation of Cd and a marked increase in Mn indicated strongly reduced vertical mixing in the Gulf of California during the mature phase of El Niño. The oceanic warming during El Niño events produces a relaxation of upwelling and a stabilization of the thermocline, which may act as a physical barrier limiting the transport of Cd from deeper waters into the surface layer. In turn, this oceanic condition can increase the residence time of particulate-Mn in surface waters, allowing an increase in the photo-reduction of particulate-Mn and the release of available Mn into the dissolved phase. These results support the use of Mn/Ca and Cd/Ca ratios in biogenic carbonates as tracers of increases in ocean stratification and trade wind weakening and/or collapse in the ETNP during <span class="hlt">ENSO</span> episodes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.5539L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.5539L"><span><span class="hlt">ENSO</span> effects on MLT diurnal tides: A 21 year reanalysis data-driven GAIA model simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Huixin; Sun, Yang-Yi; Miyoshi, Yasunobu; Jin, Hidekatsu</p> <p>2017-05-01</p> <p>Tidal responses to El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) in the mesosphere and lower thermosphere (MLT) are investigated for the first time using reanalysis data-driven simulations covering 21 years. The simulation is carried out with the Ground-to-topside Atmosphere-Ionosphere model for Aeronomy (GAIA) during 1996-2016, which covers nine <span class="hlt">ENSO</span> events. <span class="hlt">ENSO</span> impacts on diurnal tides at 100 km altitude are analyzed and cross-compared among temperature (T), zonal wind (U), and meridional wind (V), which reveals the following salient features: (1) Tidal response can differ significantly among T, U, and V in terms of magnitude and latitudinal structure, making detection of <span class="hlt">ENSO</span> effects sensitive to the parameter used and the location of a ground station; (2) the nonmigrating DE3 tide in T and U shows a prominent hemisphere asymmetric response to La Niña, with an increase between 0° and 30°N and a decrease between 30° and 0°S. In contrast, DE3 in V exhibits no significant response; (3) the migrating DW1 enhances during El Niño in equatorial regions for T and U but in off-equatorial regions for V. As the first <span class="hlt">ENSO</span> study based on reanalysis-driven simulations, GAIA's full set of tidal responses in T, U, and V provides us with a necessary global context to better understand and cross-compare observations during <span class="hlt">ENSO</span> events. Comparisons with observations during the 1997-98 El Niño and 2010-11 La Niña reveal good agreement in both magnitude and timing. Comparisons with "free-run" WACCM simulations (T) show consistent results in nonmigrating tides DE2 and DE3 but differences in the migrating DW1 tide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JMiMi..15.1271M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JMiMi..15.1271M"><span>Microprocessing of ITO and <span class="hlt">a-Si</span> thin films using ns laser sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molpeceres, C.; Lauzurica, S.; Ocaña, J. L.; Gandía, J. J.; Urbina, L.; Cárabe, J.</p> <p>2005-06-01</p> <p>Selective ablation of thin films for the development of new photovoltaic panels and sensoring devices based on amorphous silicon (<span class="hlt">a-Si</span>) is an emerging field, in which laser micromachining systems appear as appropriate tools for process development and device fabrication. In particular, a promising application is the development of purely photovoltaic position sensors. Standard p-i-n or Schottky configurations using transparent conductive oxides (TCO), <span class="hlt">a-Si</span> and metals are especially well suited for these applications, appearing selective laser ablation as an ideal process for controlled material patterning and isolation. In this work a detailed study of laser ablation of a widely used TCO, indium-tin-oxide (ITO), and <span class="hlt">a-Si</span> thin films of different thicknesses is presented, with special emphasis on the morphological analysis of the generated grooves. Excimer (KrF, λ = 248 nm) and DPSS lasers (λ = 355 and λ = 1064 nm) with nanosecond pulse duration have been used for material patterning. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) techniques have been applied for the characterization of the ablated grooves. Additionally, process parametric windows have been determined in order to assess this technology as potentially competitive to standard photolithographic processes. The encouraging results obtained, with well-defined ablation grooves having thicknesses in the order of 10 µm both in ITO and in <span class="hlt">a-Si</span>, open up the possibility of developing a high-performance double Schottky photovoltaic matrix position sensor.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48..405V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48..405V"><span>The complex influence of <span class="hlt">ENSO</span> on droughts in Ecuador</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vicente-Serrano, S. M.; Aguilar, E.; Martínez, R.; Martín-Hernández, N.; Azorin-Molina, C.; Sanchez-Lorenzo, A.; El Kenawy, A.; Tomás-Burguera, M.; Moran-Tejeda, E.; López-Moreno, J. I.; Revuelto, J.; Beguería, S.; Nieto, J. J.; Drumond, A.; Gimeno, L.; Nieto, R.</p> <p>2017-01-01</p> <p>In this study, we analyzed the influence of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on the spatio-temporal variability of droughts in Ecuador for a 48-year period (1965-2012). Droughts were quantified from 22 high-quality and homogenized time series of precipitation and air temperature by means of the Standardized Precipitation Evapotranspiration Index. In addition, the propagation of two different <span class="hlt">ENSO</span> indices (El Niño 3.4 and El Niño 1 + 2 indices) and other atmospheric circulation processes (e.g., vertical velocity) on different time-scales of drought severity were investigated. The results showed a very complex influence of <span class="hlt">ENSO</span> on drought behavior across Ecuador, with two regional patterns in the evolution of droughts: (1) the Andean chain with no changes in drought severity, and (2) the Western plains with less severe and frequent droughts. We also detected that drought variability in the Andes mountains is explained by the El Niño 3.4 index [sea surface temperature (SST) anomalies in the central Pacific], whereas the Western plains are much more driven by El Niño 1 + 2 index (SST anomalies in the eastern Pacific). Moreover, it was also observed that El Niño and La Niña phases enhance droughts in the Andes and Western plains regions, respectively. The results of this work could be crucial for predicting and monitoring drought variability and intensity in Ecuador.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP22B..06U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP22B..06U"><span>Holocene ITCZ and <span class="hlt">ENSO</span>-driven climate variability from the Panama isthmus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Urrego, D. H.; Aronson, R. B.; Bush, M. B.</p> <p>2009-12-01</p> <p>Holocene climate has previously been considered relatively stable compared to Pleistocene fluctuations. Recent paleoclimatic reconstructions have shown, however, that Holocene climatic variability is large and that the key to understanding and predicting responses to current climate change could lie in Holocene climatic history. In tropical regions, one of the most important oceanic-atmospheric systems regulating present and past interannual climatic fluctuations is the InterTropical Convergence Zone (ITCZ). Several hypotheses have been postulated to explain Holocene climate oscillations and their impacts in Northern South America. One of these hypotheses is that reduced precipitation during the mid-Holocene in the Caribbean and off the coast of Venezuela resulted from a southward migration of the ITCZ’s mean annual position (1, 2). In turn, this southward movement was associated with changes in the location of warm pools and insolation maxima regions in the tropical Atlantic. However, oscillations in Pacific warm pools should be expected to influence the annual ITCZ cycle as well. The latitudinal positions of these warm pools in the Pacific are directly influenced by <span class="hlt">ENSO</span> (El Niño Southern Oscillation), and are predicted to move south during El Niño (warm-<span class="hlt">ENSO</span>) years. A mid-Holocene increase in the frequency of warm <span class="hlt">ENSO</span> events is reported in the eastern Pacific after 6 ka (3, 4), and although this change occurred more than a thousand years earlier than the southward migrations of the ITCZ reconstructed from tropical Atlantic systems, we hypothesize that there must be a link between these two apparently separate events. Reconciling the roles of Atlantic versus Pacific ocean-atmosphere interactions, and the effect of Pacific phenomena like <span class="hlt">ENSO</span> on the annual position of the ITCZ are therefore crucial to understand climatic variability in tropical America. Lago La Yeguada is located in the Isthmus of Panama and its climate is determined mainly by the ITCZ, <span class="hlt">ENSO</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JCli...16....3L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JCli...16....3L"><span>Atmosphere-Ocean Variations in the Indo-Pacific Sector during <span class="hlt">ENSO</span> Episodes.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lau, Ngar-Cheung; Nath, Mary Jo</p> <p>2003-01-01</p> <p>The influences of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) events on air-sea interaction in the Indian-western Pacific (IWP) Oceans have been investigated using a general circulation model. Observed monthly sea surface temperature (SST) variations in the deep tropical eastern/central Pacific (DTEP) have been inserted in the lower boundary of this model through the 1950-99 period. At all maritime grid points outside of DTEP, the model atmosphere has been coupled with an oceanic mixed layer model with variable depth. Altogether 16 independent model runs have been conducted.Composite analysis of selected <span class="hlt">ENSO</span> episodes illustrates that the prescribed SST anomalies in DTEP affect the surface atmospheric circulation and precipitation patterns in IWP through displacements of the near-equatorial Walker circulation and generation of Rossby wave modes in the subtropics. Such atmospheric responses modulate the surface fluxes as well as the oceanic mixed layer depth, and thereby establish a well-defined SST anomaly pattern in the IWP sector several months after the peak in <span class="hlt">ENSO</span> forcing in DTEP. In most parts of the IWP region, the net SST tendency induced by atmospheric changes has the same polarity as the local composite SST anomaly, thus indicating that the atmospheric forcing acts to reinforce the underlying SST signal.By analyzing the output from a suite of auxiliary experiments, it is demonstrated that the SST perturbations in IWP (which are primarily generated by <span class="hlt">ENSO</span>-related atmospheric changes) can, in turn, exert notable influences on the atmospheric conditions over that region. This feedback mechanism also plays an important role in the eastward migration of the subtropical anticyclones over the western Pacific in both hemispheres.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GPC....36...89Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GPC....36...89Z"><span>Earth rotation and <span class="hlt">ENSO</span> events: combined excitation of interannual LOD variations by multiscale atmospheric oscillations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Dawei; Ding, Xiaoli; Zhou, Yonghong; Chen, Yongqi</p> <p>2003-03-01</p> <p>Time series of the length of day characterizing the rate of Earth rotation, the atmospheric angular momentum and the Southern Oscillation Index from 1962 to 2000 are used to reexamine the relationships between the <span class="hlt">ENSO</span> events and the changes in the length of day, as well as the global atmospheric angular momentum. Particular attention is given to the different effects of the 1982-1983 and 1997-1998 <span class="hlt">ENSO</span> events on the variations of Earth rotation. The combined effects of multiscale atmospheric oscillations (seasonal, quasi-biennial and <span class="hlt">ENSO</span> time scales) on the anomalous variations of the interannual rates of Earth rotation are revealed in this paper by studying the wavelet spectra of the data series.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1395870-enso-related-precipitation-its-statistical-relationship-walker-circulation-trend-cmip5-amip-models','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1395870-enso-related-precipitation-its-statistical-relationship-walker-circulation-trend-cmip5-amip-models"><span><span class="hlt">ENSO</span>-Related Precipitation and Its Statistical Relationship with the Walker Circulation Trend in CMIP5 AMIP Models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Yim, Bo; Yeh, Sang -Wook; Sohn, Byung -Ju</p> <p>2016-01-29</p> <p>Observational evidence shows that the Walker circulation (WC) in the tropical Pacific has strengthened in recent decades. In this study, we examine the WC trend for 1979–2005 and its relationship with the precipitation associated with the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) using the sea surface temperature (SST)-constrained Atmospheric Model Intercomparison Project (AMIP) simulations of the Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models. All of the 29 models show a strengthening of the WC trend in response to an increase in the SST zonal gradient along the equator. Despite the same SST-constrained AMIP simulations, however, a large diversity ismore » found among the CMIP5 climate models in the magnitude of the WC trend. The relationship between the WC trend and precipitation anomalies (PRCPAs) associated with <span class="hlt">ENSO</span> (<span class="hlt">ENSO</span>-related PRCPAs) shows that the longitudinal position of the <span class="hlt">ENSO</span>-related PRCPAs in the western tropical Pacific is closely related to the magnitude of the WC trend. Specifically, it is found that the strengthening of the WC trend is large (small) in the CMIP5 AMIP simulations in which the <span class="hlt">ENSO</span>-related PRCPAs are located relatively westward (eastward) in the western tropical Pacific. Furthermore, the zonal shift of the <span class="hlt">ENSO</span>-related precipitation in the western tropical Pacific, which is associated with the climatological mean precipitation in the tropical Pacific, could play an important role in modifying the WC trend in the CMIP5 climate models.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNG31A0159G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNG31A0159G"><span>Using a 4D-Variational Method to Optimize Model Parameters in an Intermediate Coupled Model of <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, C.; Zhang, R. H.</p> <p>2017-12-01</p> <p>Large biases exist in real-time <span class="hlt">ENSO</span> prediction, which is attributed to uncertainties in initial conditions and model parameters. Previously, a four dimentional variational (4D-Var) data assimilation system was developed for an intermediate coupled model (ICM) and used to improve <span class="hlt">ENSO</span> modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for <span class="hlt">ENSO</span> is related to the anomalous temperature of subsurface water entrained into the mixed layer (Te), which is empirically and explicitly related to sea level (SL) variation, written as Te=αTe×FTe (SL). The introduced parameter, αTe, represents the strength of the thermocline effect on sea surface temperature (SST; referred as the thermocline effect). A numerical procedure is developed to optimize this model parameter through the 4D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having initial condition optimized only and having initial condition plus this additional model parameter optimized both are compared. It is shown that <span class="hlt">ENSO</span> evolution can be more effectively recovered by including the additional optimization of this parameter in <span class="hlt">ENSO</span> modeling. The demonstrated feasibility of optimizing model parameter and initial condition together through the 4D-Var method provides a modeling platform for <span class="hlt">ENSO</span> studies. Further applications of the 4D-Var data assimilation system implemented in the ICM are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070038265&hterms=warm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwarm','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070038265&hterms=warm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwarm"><span>Response of Global Lightning Activity Observed by the TRMM/LIS During Warm and Cold <span class="hlt">ENSO</span> Phases</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chronis, Themis G.; Cecil, Dan; Goodman, Steven J.; Buechler, Dennis</p> <p>2007-01-01</p> <p>This paper investigates the response of global lightning activity to the transition from the warm (January February March-JFM 1998) to the cold (JFM 1999) <span class="hlt">ENSO</span> phase. The nine-year global lightning climatology for these months from the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) provides the observational baseline. Flash rate density is computed on a 5.0x5.0 degree lat/lon grid within the LIS coverage area (between approx.37.5 N and S) for each three month period. The flash rate density anomalies from this climatology are examined for these months in 1998 and 1999. The observed lightning anomalies spatially match the documented general circulation features that accompany the warm and cold <span class="hlt">ENSO</span> events. During the warm <span class="hlt">ENSO</span> phase the dominant positive lightning anomalies are located mostly over the Western Hemisphere and more specifically over Gulf of Mexico, Caribbean and Northern Mid-Atlantic. We further investigate specifically the Northern Mid-Atlantic related anomaly features since these show strong relation to the North Atlantic Oscillation (NAO). Furthermore these observed anomaly patterns show strong spatial agreement with anomalous upper level (200 mb) cold core cyclonic circulations. Positive sea surface temperature anomalies during the warm <span class="hlt">ENSO</span> phase also affect the lightning activity, but this is mostly observed near coastal environments. Over the open tropical oceans, there is climatologically less lightning and the anomalies are less pronounced. Warm <span class="hlt">ENSO</span> related anomalies over the Eastern Hemisphere are most prominent over the South China coast. The transition to the cold <span class="hlt">ENSO</span> phase illustrates the detected lightning anomalies to be more pronounced over East and West Pacific. A comparison of total global lightning between warm and cold <span class="hlt">ENSO</span> phase reveals no significant difference, although prominent regional anomalies are located over mostly oceanic environments. All three tropical "chimneys" (Maritime Continent, Central</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27432777','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27432777"><span>Climate Change and <span class="hlt">ENSO</span> Effects on Southeastern US Climate Patterns and Maize Yield.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mourtzinis, Spyridon; Ortiz, Brenda V; Damianidis, Damianos</p> <p>2016-07-19</p> <p>Climate change has a strong influence on weather patterns and significantly affects crop yields globally. El Niño Southern Oscillation (<span class="hlt">ENSO</span>) has a strong influence on the U.S. climate and is related to agricultural production variability. <span class="hlt">ENSO</span> effects are location-specific and in southeastern U.S. strongly connect with climate variability. When combined with climate change, the effects on growing season climate patterns and crop yields might be greater than expected. In our study, historical monthly precipitation and temperature data were coupled with non-irrigated maize yield data (33-43 years depending on the location) to show a potential yield suppression of ~15% for one °C increase in southeastern U.S. growing season maximum temperature. Yield suppression ranged between -25 and -2% among locations suppressing the southeastern U.S. average yield trend since 1981 by 17 kg ha(-1)year(-1) (~25%), mainly due to year-to-year June temperature anomalies. Yields varied among <span class="hlt">ENSO</span> phases from 1971-2013, with greater yields observed during El Niño phase. During La Niña years, maximum June temperatures were higher than Neutral and El Niño, whereas June precipitation was lower than El Niño years. Our data highlight the importance of developing location-specific adaptation strategies quantifying both, climate change and <span class="hlt">ENSO</span> effects on month-specific growing season climate conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H41A1408D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H41A1408D"><span>Forecasting of Seasonal Rainfall using <span class="hlt">ENSO</span> and IOD teleconnection with Classification Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Silva, T.; Hornberger, G. M.</p> <p>2017-12-01</p> <p>Seasonal to annual forecasts of precipitation patterns are very important for water infrastructure management. In particular, such forecasts can be used to inform decisions about the operation of multipurpose reservoir systems in the face of changing climate conditions. Success in making useful forecasts often is achieved by considering climate teleconnections such as the El-Nino-Southern Oscillation (<span class="hlt">ENSO</span>), Indian Ocean Dipole (IOD) as related to sea surface temperature variations. We present an analysis to explore the utility of using rainfall relationships in Sri Lanka with <span class="hlt">ENSO</span> and IOD to predict rainfall to the Mahaweli, river basin. Forecasting of rainfall as classes - above normal, normal, and below normal - can be useful for water resource management decision making. Quadratic discrimination analysis (QDA) and random forest models are used to identify the patterns of rainfall classes with respect to <span class="hlt">ENSO</span> and IOD indices. These models can be used to forecast the likelihood of areal rainfall anomalies using predicted climate indices. Results can be used for decisions regarding allocation of water for agriculture and electricity generation within the Mahaweli project of Sri Lanka.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.6597Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.6597Z"><span>A delay differential model of <span class="hlt">ENSO</span> variability: Extreme values and stability analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaliapin, I.; Ghil, M.</p> <p>2009-04-01</p> <p>We consider a delay differential equation (DDE) model for El-Niño Southern Oscillation (<span class="hlt">ENSO</span>) variability [Ghil et al. (2008), Nonlin. Proc. Geophys., 15, 417-433.] The model combines two key mechanisms that participate in <span class="hlt">ENSO</span> dynamics: delayed negative feedback and seasonal forcing. Toy models of this type were shown to capture major features of the <span class="hlt">ENSO</span> phenomenon [Jin et al., Science (1994); Tziperman et al., Science (1994)]; they provide a convenient paradigm for explaining interannual <span class="hlt">ENSO</span> variability and shed new light on its dynamical properties. So far, though, DDE model studies of <span class="hlt">ENSO</span> have been limited to linear stability analysis of steady-state solutions, which are not typical in forced systems, case studies of particular trajectories, or one-dimensional scenarios of transition to chaos, varying a single parameter while the others are kept fixed. In this work we take several steps toward a comprehensive analysis of DDE models relevant for <span class="hlt">ENSO</span> phenomenology and illustrate the complexity of phase-parameter space structure for even such a simple model of climate dynamics. We formulate an initial value problem for our model and prove the existence, uniqueness, and continuous dependence theorem. We then use this theoretical result to perform detailed numerical stability analyses of the model in the three-dimensional space of its physically relevant parameters: strength of seasonal forcing b, atmosphere-ocean coupling ΰ, and propagation period ? of oceanic waves across the Tropical Pacific. Two regimes of variability, stable and unstable, are reported; they are separated by a sharp neutral curve in the (b,?) plane at constant ΰ. The detailed structure of the neutral curve becomes very irregular and possibly fractal, while individual trajectories within the unstable region become highly complex and possibly chaotic, as the atmosphere-ocean coupling ΰ increases. In the unstable regime, spontaneous transitions occur in the mean temperature (i</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170007411&hterms=gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgravity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170007411&hterms=gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgravity"><span>The QBO, Gravity Waves Forced by Tropical Convection, and <span class="hlt">ENSO</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Geller, Marvin A.; Zhou, Tiehan; Yuan, Wei</p> <p>2016-01-01</p> <p>By means of theory, a simplified cartoon illustrating wave forcing of the stratospheric quasi-biennial oscillation (QBO), and general circulation modeling of the QBO, it is argued that the period of the QBO is mainly controlled by the magnitude of the gravity wave (GW) vertical fluxes of horizontal momentum (GWMF) forcing the QBO, while the QBO amplitude is mainly determined by the phase speeds of the GWs that make up this momentum flux. It is furthermore argued that it is the zonally averaged GWMF that principally determines the QBO period irrespective of the longitudinal distribution of this GW momentum flux. These concepts are used to develop a hypothesis for the cause of a previously reported El Nino- Southern Oscillation (<span class="hlt">ENSO</span>) modulation of QBO periods and amplitudes. Some observational evidence is reported for the <span class="hlt">ENSO</span> modulation of QBO amplitudes to have been different before the 1980s than after about 1990. A hypothesis is also given to explain this in terms of the different <span class="hlt">ENSO</span> modulation of tropical deep convection that took place before the 1980s from that which occurred after about 1990. The observational evidence, while consistent with our hypotheses, does not prove that our hypotheses are correct given the small number of El Ninos and La Ninas that occurred in the early and later periods. Further research is needed to support or refute our hypotheses</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4111296','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4111296"><span>δ 18O in the Tropical Conifer Agathis robusta Records <span class="hlt">ENSO</span>-Related Precipitation Variations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Boysen, Bjorn M. M.; Evans, Michael N.; Baker, Patrick J.</p> <p>2014-01-01</p> <p>Long-lived trees from tropical Australasia are a potential source of information about internal variability of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), because they occur in a region where precipitation variability is closely associated with <span class="hlt">ENSO</span> activity. We measured tree-ring width and oxygen isotopic composition (O) of -cellulose from Agathis robusta (Queensland Kauri) samples collected in the Atherton Tablelands, Queensland, Australia. Standard ring-width chronologies yielded low internal consistency due to the frequent presence of false ring-like anatomical features. However, in a detailed examination of the most recent 15 years of growth (1995–2010), we found significant correlation between O and local precipitation, the latter associated with <span class="hlt">ENSO</span> activity. The results are consistent with process-based forward modeling of the oxygen isotopic composition of -cellulose. The O record also enabled us to confirm the presence of a false growth ring in one of the three samples in the composite record, and to determine that it occurred as a consequence of anomalously low rainfall in the middle of the 2004/5 rainy season. The combination of incremental growth and isotopic measures may be a powerful approach to development of long-term (150+ year) <span class="hlt">ENSO</span> reconstructions from the terrestrial tropics of Australasia. PMID:25062034</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ThApC.129.1059D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ThApC.129.1059D"><span>Predicting monthly precipitation along coastal Ecuador: <span class="hlt">ENSO</span> and transfer function models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Guenni, Lelys B.; García, Mariangel; Muñoz, Ángel G.; Santos, José L.; Cedeño, Alexandra; Perugachi, Carlos; Castillo, José</p> <p>2017-08-01</p> <p>It is well known that El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) modifies precipitation patterns in several parts of the world. One of the most impacted areas is the western coast of South America, where Ecuador is located. El Niño events that occurred in 1982-1983, 1987-1988, 1991-1992, and 1997-1998 produced important positive rainfall anomalies in the coastal zone of Ecuador, bringing considerable damage to livelihoods, agriculture, and infrastructure. Operational climate forecasts in the region provide only seasonal scale (e.g., 3-month averages) information, but during <span class="hlt">ENSO</span> events it is key for decision-makers to use reliable sub-seasonal scale forecasts, which at the present time are still non-existent in most parts of the world. This study analyzes the potential predictability of coastal Ecuador rainfall at monthly scale. Instead of the discrete approach that considers training models using only particular seasons, continuous (i.e., all available months are used) transfer function models are built using standard <span class="hlt">ENSO</span> indices to explore rainfall forecast skill along the Ecuadorian coast and Galápagos Islands. The modeling approach considers a large-scale contribution, represented by the role of a sea-surface temperature index, and a local-scale contribution represented here via the use of previous precipitation observed in the same station. The study found that the Niño3 index is the best <span class="hlt">ENSO</span> predictor of monthly coastal rainfall, with a lagged response varying from 0 months (simultaneous) for Galápagos up to 3 months for the continental locations considered. Model validation indicates that the skill is similar to the one obtained using principal component regression models for the same kind of experiments. It is suggested that the proposed approach could provide skillful rainfall forecasts at monthly scale for up to a few months in advance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..118a2052Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..118a2052Y"><span>Coral based-<span class="hlt">ENSO</span>/IOD related climate variability in Indonesia: a review</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yudawati Cahyarini, Sri; Henrizan, Marfasran</p> <p>2018-02-01</p> <p>Indonesia is located in the prominent site to study climate variability as it lies between Pacific and Indian Ocean. It has consequences to the regional climate in Indonesia that its climate variability is influenced by the climate events in the Pacific oceans (e.g. <span class="hlt">ENSO</span>) and in the Indian ocean (e.g. IOD), and monsoon as well as Indonesian Throughflow (ITF). Northwestern monsoon causes rainfall in the region of Indonesia, while reversely Southwestern monsoon causes dry season around Indonesia. The <span class="hlt">ENSO</span> warm phase called El Nino causes several droughts in Indonesian region, reversely the La Nina causes flooding in some regions in Indonesia. However, the impact of <span class="hlt">ENSO</span> in Indonesia is different from one place to the others. Having better understanding on the climate phenomenon and its impact to the region requires long time series climate data. Paleoclimate study which provides climate data back into hundreds to thousands even to million years overcome this requirement. Coral Sr/Ca can provide information on past sea surface temperature (SST) and paired Sr/Ca and δ18O may be used to reconstruct variations in the precipitation balance (salinity) at monthly to annual interannual resolution. Several climate studies based on coral geochemical records in Indonesia show that coral Sr/Ca and δ18O from Indonesian records SST and salinity respectively. Coral Sr/Ca from inshore Seribu islands complex shows more air temperature rather than SST. Modern coral from Timor shows the impact of <span class="hlt">ENSO</span> and IOD to the saliniy and SST is different at Timor sea. This result should be taken into account when interpreting Paleoclimate records over Indonesia. Timor coral also shows more pronounced low frequency SST variability compared to the SST reanalysis (model). The longer data of low frequency variability will improve the understanding of warming trend in this climatically important region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GBioC..31..901E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GBioC..31..901E"><span>Impacts of <span class="hlt">ENSO</span> on air-sea oxygen exchange: Observations and mechanisms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eddebbar, Yassir A.; Long, Matthew C.; Resplandy, Laure; Rödenbeck, Christian; Rodgers, Keith B.; Manizza, Manfredi; Keeling, Ralph F.</p> <p>2017-05-01</p> <p>Models and observations of atmospheric potential oxygen (APO ≃ O2 + 1.1 * CO2) are used to investigate the influence of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on air-sea O2 exchange. An atmospheric transport inversion of APO data from the Scripps flask network shows significant interannual variability in tropical APO fluxes that is positively correlated with the Niño3.4 index, indicating anomalous ocean outgassing of APO during El Niño. Hindcast simulations of the Community Earth System Model (CESM) and the Institut Pierre-Simon Laplace model show similar APO sensitivity to <span class="hlt">ENSO</span>, differing from the Geophysical Fluid Dynamics Laboratory model, which shows an opposite APO response. In all models, O2 accounts for most APO flux variations. Detailed analysis in CESM shows that the O2 response is driven primarily by <span class="hlt">ENSO</span> modulation of the source and rate of equatorial upwelling, which moderates the intensity of O2 uptake due to vertical transport of low-O2 waters. These upwelling changes dominate over counteracting effects of biological productivity and thermally driven O2 exchange. During El Niño, shallower and weaker upwelling leads to anomalous O2 outgassing, whereas deeper and intensified upwelling during La Niña drives enhanced O2 uptake. This response is strongly localized along the central and eastern equatorial Pacific, leading to an equatorial zonal dipole in atmospheric anomalies of APO. This dipole is further intensified by <span class="hlt">ENSO</span>-related changes in winds, reconciling apparently conflicting APO observations in the tropical Pacific. These findings suggest a substantial and complex response of the oceanic O2 cycle to climate variability that is significantly (>50%) underestimated in magnitude by ocean models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021246','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021246"><span>Decadal variations in the strength of <span class="hlt">ENSO</span> teleconnections with precipitation in the western United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McCabe, G.J.; Dettinger, M.D.</p> <p>1999-01-01</p> <p>Changing patterns of correlations between the historical average June-November Southern Oscillation Index (SOI) and October-March precipitation totals for 84 climate divisions in the western US indicate a large amount of variability in SOI/precipitation relations on decadal time scales. Correlations of western US precipitation with SOI and other indices of tropical El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) processes were much weaker from 1920 to 1950 than during recent decades. This variability in teleconnections is associated with the character of tropical air-sea interactions as indexed by the number of out-of-phase SOI/tropical sea surface temperature (SST) episodes, and with decadal variability in the North Pacific Ocean as indexed by the Pacific Decadal Oscillation (PDO). <span class="hlt">ENSO</span> teleconnections with precipitation in the western US are strong when SOI and NINO3 are out-of-phase and PDO is negative. <span class="hlt">ENSO</span> teleconnections are weak when SOI and NINO3 are weakly correlated and PDO is positive. Decadal modes of tropical and North Pacific Ocean climate variability are important indicators of periods when <span class="hlt">ENSO</span> indices, like SOI, can be used as reliable predictors of winter precipitation in the US.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120010529','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120010529"><span>A Statistical Model of Tropical Cyclone Tracks in the Western North Pacific with <span class="hlt">ENSO</span>-Dependent Cyclogenesis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yonekura, Emmi; Hall, Timothy M.</p> <p>2011-01-01</p> <p>A new statistical model for western North Pacific Ocean tropical cyclone genesis and tracks is developed and applied to estimate regionally resolved tropical cyclone landfall rates along the coasts of the Asian mainland, Japan, and the Philippines. The model is constructed on International Best Track Archive for Climate Stewardship (IBTrACS) 1945-2007 historical data for the western North Pacific. The model is evaluated in several ways, including comparing the stochastic spread in simulated landfall rates with historic landfall rates. Although certain biases have been detected, overall the model performs well on the diagnostic tests, for example, reproducing well the geographic distribution of landfall rates. Western North Pacific cyclogenesis is influenced by El Nino-Southern Oscillation (<span class="hlt">ENSO</span>). This dependence is incorporated in the model s genesis component to project the <span class="hlt">ENSO</span>-genesis dependence onto landfall rates. There is a pronounced shift southeastward in cyclogenesis and a small but significant reduction in basinwide annual counts with increasing <span class="hlt">ENSO</span> index value. On almost all regions of coast, landfall rates are significantly higher in a negative <span class="hlt">ENSO</span> state (La Nina).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP23D..07R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP23D..07R"><span>Central Tropical Pacific Variability And <span class="hlt">ENSO</span> Response To Changing Climate Boundary Conditions: Evidence From Individual Line Island Foraminifera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rustic, G. T.; Polissar, P. J.; Ravelo, A. C.; White, S. M.</p> <p>2017-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) plays a dominant role in Earth's climate variability. Paleoceanographic evidence suggests that <span class="hlt">ENSO</span> has changed in the past, and these changes have been linked to large-scale climatic shifts. While a close relationship between <span class="hlt">ENSO</span> evolution and climate boundary conditions has been predicted, testing these predictions remains challenging. These climate boundary conditions, including insolation, the mean surface temperature gradient of the tropical Pacific, global ice volume, and tropical thermocline depth, often co-vary and may work together to suppress or enhance the ocean-atmosphere feedbacks that drive <span class="hlt">ENSO</span> variability. Furthermore, suitable paleo-archives spanning multiple climate states are sparse. We have aimed to test <span class="hlt">ENSO</span> response to changing climate boundary conditions by generating new reconstructions of mixed-layer variability from sedimentary archives spanning the last three glacial-interglacial cycles from the Central Tropical Pacific Line Islands, where El Niño is strongly expressed. We analyzed Mg/Ca ratios from individual foraminifera to reconstruct mixed-layer variability at discrete time intervals representing combinations of climatic boundary conditions from the middle Holocene to Marine Isotope Stage (MIS) 8. We observe changes in the mixed-layer temperature variability during MIS 5 and during the previous interglacial (MIS 7) showing significant reductions in <span class="hlt">ENSO</span> amplitude. Differences in variability during glacial and interglacial intervals are also observed. Additionally, we reconstructed mixed-layer and thermocline conditions using multi-species Mg/Ca and stable isotope measurements to more fully characterize the state of the Central Tropical Pacific during these intervals. These reconstructions provide us with a unique view of Central Tropical Pacific variability and water-column structure at discrete intervals under varying boundary climate conditions with which to assess factors that shape <span class="hlt">ENSO</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950017276','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950017276"><span><span class="hlt">ASI</span>'s space automation and robotics programs: The second step</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dipippo, Simonetta</p> <p>1994-01-01</p> <p>The strategic decisions taken by <span class="hlt">ASI</span> in the last few years in building up the overall A&R program, represent the technological drivers for other applications (i.e., internal automation of the Columbus Orbital Facility in the ESA Manned Space program, applications to mobile robots both in space and non-space environments, etc...). In this context, the main area of application now emerging is the scientific missions domain. Due to the broad range of applications of the developed technologies, both in the in-orbit servicing and maintenance of space structures and scientific missions, <span class="hlt">ASI</span> foresaw the need to have a common technological development path, mainly focusing on: (1) control; (2) manipulation; (3) on-board computing; (4) sensors; and (5) teleoperation. Before entering into new applications in the scientific missions field, a brief overview of the status of the SPIDER related projects is given, underlining also the possible new applications for the LEO/GEO space structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20160004698&hterms=water+availability&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwater%2Bavailability','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20160004698&hterms=water+availability&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwater%2Bavailability"><span>Sensitivity of Water Scarcity Events to <span class="hlt">ENSO</span>-Driven Climate Variability at the Global Scale</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Veldkamp, T. I. E.; Eisner, S.; Wada, Y.; Aerts, J. C. J. H.; Ward, P. J.</p> <p>2015-01-01</p> <p>Globally, freshwater shortage is one of the most dangerous risks for society. Changing hydro-climatic and socioeconomic conditions have aggravated water scarcity over the past decades. A wide range of studies show that water scarcity will intensify in the future, as a result of both increased consumptive water use and, in some regions, climate change. Although it is well-known that El Niño- Southern Oscillation (<span class="hlt">ENSO</span>) affects patterns of precipitation and drought at global and regional scales, little attention has yet been paid to the impacts of climate variability on water scarcity conditions, despite its importance for adaptation planning. Therefore, we present the first global-scale sensitivity assessment of water scarcity to <span class="hlt">ENSO</span>, the most dominant signal of climate variability. We show that over the time period 1961-2010, both water availability and water scarcity conditions are significantly correlated with <span class="hlt">ENSO</span>-driven climate variability over a large proportion of the global land area (> 28.1 %); an area inhabited by more than 31.4% of the global population. We also found, however, that climate variability alone is often not enough to trigger the actual incidence of water scarcity events. The sensitivity of a region to water scarcity events, expressed in terms of land area or population exposed, is determined by both hydro-climatic and socioeconomic conditions. Currently, the population actually impacted by water scarcity events consists of 39.6% (CTA: consumption-to-availability ratio) and 41.1% (WCI: water crowding index) of the global population, whilst only 11.4% (CTA) and 15.9% (WCI) of the global population is at the same time living in areas sensitive to <span class="hlt">ENSO</span>-driven climate variability. These results are contrasted, however, by differences in growth rates found under changing socioeconomic conditions, which are relatively high in regions exposed to water scarcity events. Given the correlations found between <span class="hlt">ENSO</span> and water availability and scarcity</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018APJAS..54...63S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018APJAS..54...63S"><span>Interdecadal Change in the Relationship Between the North Pacific Oscillation and the Pacific Meridional Mode and Its Impact on <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shin, So-Jung; An, Soon-Il</p> <p>2018-02-01</p> <p>Two leading but independent modes of Northern Pacific atmospheric circulation: the North Pacific Oscillation (NPO) and the Pacific Meridional Mode (PMM), are known external triggers of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) by the sequential migration of sea surface temperature (SST) anomalies into the tropics possibly by means of wind-evaporation-SST (WES) feedbacks. Because of the similar roles of NPO and PMM, most previous studies have explored them with no separation. Here, we investigate their independent and combined effects in triggering <span class="hlt">ENSO</span>, and find that when the NPO and PMM occur simultaneously during spring, <span class="hlt">ENSO</span> or <span class="hlt">ENSO</span>-like SST anomalies are generated during the following winter; whereas when either the NPO or PMM occur alone, <span class="hlt">ENSO</span> events rarely occur. Furthermore, the relationship between NPO and PMM shows noticeable interdecadal variability, which is related to decadal changes in the mean upper-level jet stream over the North Pacific. Changes in the upper-level jet stream modify the location of the center of the Aleutian Low, which plays a role in bridging the NPO and PMM processes, especially when it migrates to the southwest. The period when NPO and PMM are well correlated coincides somewhat with the active <span class="hlt">ENSO</span> period, and vice versa, indicating that a more efficient trigger due to combined NPO-PMM processes results in a higher variation of <span class="hlt">ENSO</span>. Finally, analysis of the coupled model control simulations strongly supports our observational analysis results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMGC24G..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMGC24G..05P"><span>PDO and <span class="hlt">ENSO</span> Sea Surface Temperature Anomalies Control Grassland Plant Production across the United States Great Plains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parton, W. J.; Del Grosso, S. J.; Smith, W. K.; Chen, M.</p> <p>2017-12-01</p> <p>The El Nino Southern Oscillation (<span class="hlt">ENSO</span>) and Pacific Decadal Oscillation (PDO) are multi-annual to multi-decadal climate patterns defined by ocean temperature anomalies that can strongly modulate climate variability. Here we evaluated the impacts of PDO and <span class="hlt">ENSO</span> sea surface temperature (SST) anomalies on observed grassland above ground plant production (ANPP; 1940 to 2015), spring (April to July) cumulative actual evapotranspiration (iAET; 1900 to 2015) , and satellite-derived growing season (April to October) cumulative normalized difference vegetation index (iNDVI 1982 to 2015) across the United States Great Plains. The results showed that grassland ANPP is well correlated to iAET (r2=0.69) and iNDVI (r2=0.50 to 0.70) for the Cheyenne Wyoming and Northeastern Colorado long-term ANPP sites. At the site scale, during the negative phase of the PDO, we find ANPP is much lower (25%) and that variability of iAET, iNDVI, and ANPP are much higher (2 to 3 times) compared to the warm phase PDO. Further, we find there is a high frequency of below normal iAET when PDO and <span class="hlt">ENSO</span> SST's are both negative, while there is a high frequency of above normal iAET when PDO and <span class="hlt">ENSO</span> values are positive. At the regional scale, iAET, iNDVI, and modeled ANPP data sets show that plant production and iAET values are high in the southern Great Plains and low in the northern Great Plains when spring PDO and <span class="hlt">ENSO</span> are both in the positive phase, while the opposite pattern is observed when both PDO and <span class="hlt">ENSO</span> are both in the negative phase. Variability of iAET, iNDVI, and modeled ANPP are much higher in the central Great Plains during the negative phase PDO. We demonstrate clearly that the PDO and <span class="hlt">ENSO</span> SST anomalies have large impacts on mean and variability of grassland plant production across the Great Plains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3651F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3651F"><span><span class="hlt">ENSO</span>-related Interannual Variability of Southern Hemisphere Atmospheric Circulation: Assessment and Projected Changes in CMIP5 Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frederiksen, Carsten; Grainger, Simon; Zheng, Xiaogu; Sisson, Janice</p> <p>2013-04-01</p> <p><span class="hlt">ENSO</span> variability is an important driver of the Southern Hemisphere (SH) atmospheric circulation. Understanding the observed and projected changes in <span class="hlt">ENSO</span> variability is therefore important to understanding changes in Australian surface climate. Using a recently developed methodology (Zheng et al., 2009), the coherent patterns, or modes, of <span class="hlt">ENSO</span>-related variability in the SH atmospheric circulation can be separated from modes that are related to intraseasonal variability or to changes in radiative forcings. Under this methodology, the seasonal mean SH 500 hPa geopotential height is considered to consist of three components. These are: (1) an intraseasonal component related to internal dynamics on intraseasonal time scales; (2) a slow-internal component related to internal dynamics on slowly varying (interannual or longer) time scales, including <span class="hlt">ENSO</span>; and (3) a slow-external component related to external (i.e. radiative) forcings. Empirical Orthogonal Functions (EOFs) are used to represent the modes of variability of the interannual covariance of the three components. An assessment is first made of the modes in models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) dataset for the SH summer and winter seasons in the 20th century. In reanalysis data, two EOFs of the slow component (which includes the slow-internal and slow-external components) have been found to be related to <span class="hlt">ENSO</span> variability (Frederiksen and Zheng, 2007). In SH summer, the CMIP5 models reproduce the leading <span class="hlt">ENSO</span> mode very well when the structures of the EOF and the associated SST, and associated variance are considered. There is substantial improvement in this mode when compared with the CMIP3 models shown in Grainger et al. (2012). However, the second <span class="hlt">ENSO</span> mode in SH summer has a poorly reproduced EOF structure in the CMIP5 models, and the associated variance is generally underestimated. In SH winter, the performance of the CMIP5 models in reproducing the structure and variance is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP33B1324H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP33B1324H"><span>Tropical Pacific Mean State and <span class="hlt">ENSO</span> Variability across Marine Isotope Stage 3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hertzberg, J. E.; Schmidt, M. W.; Marcantonio, F.; Bianchi, T. S.</p> <p>2017-12-01</p> <p>The El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon is the largest natural interannual signal in the Earth's climate system and has widespread effects on global climate that impact millions of people worldwide. A series of recent research studies predict an increase in the frequency of extreme El Niño and La Niña events as Earth's climate continues to warm. In order for climate scientists to forecast how <span class="hlt">ENSO</span> will evolve in response to global warming, it is necessary to have accurate, comprehensive records of how the system has naturally changed in the past, especially across past abrupt warming events. Nevertheless, there remains significant uncertainty about past changes in tropical Pacific climate and how <span class="hlt">ENSO</span> variability relates to the millennial-scale warming events of the last ice age. This study aims to reconstruct changes in the tropical Pacific mean state and <span class="hlt">ENSO</span> variability across Marine Isotope Stage 3 from a sediment core recovered from the Eastern Equatorial Pacific cold tongue (MV1014-02-17JC, 0°10.8' S, 85°52.0' W, 2846 m water depth). In this region, thermocline temperatures are significantly correlated to <span class="hlt">ENSO</span> variability - thus, we analyzed Mg/Ca ratios in the thermocline dwelling foraminifera Neogloboquadrina dutertrei as a proxy for thermocline temperatures in the past. Bulk ( 50 tests/sample) foraminifera Mg/Ca temperatures are used to reconstruct long-term variability in the mean state, while single shell ( 1 test/sample, 60 samples) Mg/Ca analyses are used to assess thermocline temperature variance. Based on our refined age model, we find that thermocline temperature increases of up to 3.5°C occur in-step with interstadial warming events recorded in Greenland ice cores. Cooler thermocline temperatures prevail during stadial intervals and Heinrich Events. This suggests that interstadials were more El-Niño like, while stadials and Heinrich Events were more La-Niña like. These temperature changes are compared to new records of dust flux</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS11B..04P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS11B..04P"><span>Analytical Formulation of Equatorial Standing Wave Phenomena: Application to QBO and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pukite, P. R.</p> <p>2016-12-01</p> <p>Key equatorial climate phenomena such as QBO and <span class="hlt">ENSO</span> have never been adequately explained as deterministic processes. This in spite of recent research showing growing evidence of predictable behavior. This study applies the fundamental Laplace tidal equations with simplifying assumptions along the equator — i.e. no Coriolis force and a small angle approximation. To connect the analytical Sturm-Liouville results to observations, a first-order forcing consistent with a seasonally aliased Draconic or nodal lunar period (27.21d aliased into 2.36y) is applied. This has a plausible rationale as it ties a latitudinal forcing cycle via a cross-product to the longitudinal terms in the Laplace formulation. The fitted results match the features of QBO both qualitatively and quantitatively; adding second-order terms due to other seasonally aliased lunar periods provides finer detail while remaining consistent with the physical model. Further, running symbolic regression machine learning experiments on the data provided a validation to the approach, as it discovered the same analytical form and fitted values as the first principles Laplace model. These results conflict with Lindzen's QBO model, in that his original formulation fell short of making the lunar connection, even though Lindzen himself asserted "it is unlikely that lunar periods could be produced by anything other than the lunar tidal potential".By applying a similar analytical approach to <span class="hlt">ENSO</span>, we find that the tidal equations need to be replaced with a Mathieu-equation formulation consistent with describing a sloshing process in the thermocline depth. Adapting the hydrodynamic math of sloshing, we find a biennial modulation coupled with angular momentum forcing variations matching the Chandler wobble gives an impressive match over the measured <span class="hlt">ENSO</span> range of 1880 until the present. Lunar tidal periods and an additional triaxial nutation of 14 year period provide additional fidelity. The caveat is a phase</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdAtS..35..410G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdAtS..35..410G"><span>Idealized Experiments for Optimizing Model Parameters Using a 4D-Variational Method in an Intermediate Coupled Model of <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Chuan; Zhang, Rong-Hua; Wu, Xinrong; Sun, Jichang</p> <p>2018-04-01</p> <p>Large biases exist in real-time <span class="hlt">ENSO</span> prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4D variational (4D-Var) data assimilation system was developed for an intermediate coupled model (ICM) and used to improve <span class="hlt">ENSO</span> modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for <span class="hlt">ENSO</span> is related to the anomalous temperature of subsurface water entrained into the mixed layer ( T e), which is empirically and explicitly related to sea level (SL) variation. The strength of the thermocline effect on SST (referred to simply as "the thermocline effect") is represented by an introduced parameter, α Te. A numerical procedure is developed to optimize this model parameter through the 4D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having their initial condition optimized only, and having their initial condition plus this additional model parameter optimized, are compared. It is shown that <span class="hlt">ENSO</span> evolution can be more effectively recovered by including the additional optimization of this parameter in <span class="hlt">ENSO</span> modeling. The demonstrated feasibility of optimizing model parameters and initial conditions together through the 4D-Var method provides a modeling platform for <span class="hlt">ENSO</span> studies. Further applications of the 4D-Var data assimilation system implemented in the ICM are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP33B1325R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP33B1325R"><span>Calibrating a Method for Reconstructing <span class="hlt">ENSO</span> Variance in the Eastern Tropical Pacific Using Mg/Ca in Individual Planktic Foraminifera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rongstad, B.; Marchitto, T. M., Jr.; Koutavas, A.; Mekik, F.</p> <p>2017-12-01</p> <p>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is Earth's dominant mode of interannual climate variability, and is responsible for widespread climatic, ecological and societal impacts, such as reduced upwelling and fishery collapse in the eastern equatorial Pacific during El Niño events. While corals offer high resolution records of paleo-<span class="hlt">ENSO</span>, continuous and gap-free records for the tropical Pacific are rare. Individual foraminifera analyses provide an opportunity to create continuous down-core records of <span class="hlt">ENSO</span> through the construction and comparison of species-specific sea surface temperature (SST) distributions at different time periods; however, there has been little focus on calibrating this technique to modern <span class="hlt">ENSO</span> conditions. Here, we present data from a core-top calibration of individual Mg/Ca measurements in planktic foraminifera in the eastern tropical Pacific, using surface dweller G. ruber and thermocline dweller N. dutertrei. We convert the individual Mg/Ca measurements to inferred temperature distributions for each species, and then compare the distributions to modern day temperature characteristics including vertical structure, annual mean, seasonality, and interannual variability. <span class="hlt">ENSO</span> variance is theoretically inferred from the tails of the distributions: El Niño events affect the warm tail and La Niña events affect the cool tail. Finally, we discuss the utility of individual measurements of Mg/Ca in planktic foraminifera to reconstruct <span class="hlt">ENSO</span> in down-core sections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C21A0703P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C21A0703P"><span>Interannual Variability in Amundsen Sea Ice-Shelf Height Change Linked to <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paolo, F. S.; Fricker, H. A.; Padman, L.</p> <p>2015-12-01</p> <p>Atmospheric and sea-ice conditions around Antarctica, particularly in the Amundsen and Bellingshausen seas, respond to climate dynamics in the tropical Pacific Ocean on interannual time scales including the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>). It has been hypothesized that the mass balance of the Antarctic Ice Sheet, including its floating ice shelves, also responds to this climate signal; however, this has not yet been unambiguously demonstrated. We apply multivariate singular spectrum analysis (MSSA) to our 18-year (1994-2012) time series of ice-shelf height in the Amundsen Sea (AS) region. This advanced spectral method distinguishes between regular deterministic behavior ("cycles") at sub-decadal time scale and irregular behavior ("noise") at shorter time scales. Although the long-term trends of AS ice-shelf height changes are much larger than the range of interannual variability, the short-term rate of change dh/dt can vary about the trend by more than 50%. The mode of interannual variability in the AS ice-shelf height is strongly correlated with the low-frequency mode of <span class="hlt">ENSO</span> (periodicity of ~4.5 years) as represented by the Southern Oscillation Index. The ice-shelf height in the AS is expected to respond to changes in precipitation and inflows of warm subsurface Circumpolar Deep Water (CDW) into the ocean cavities under the ice shelves, altering basal melt rates. Since both of these processes affecting ice-shelf mass balance respond to changes in wind fields for different <span class="hlt">ENSO</span> states, we expect some correlation between them. We will describe the spatial structure of AS ice-shelf height response to <span class="hlt">ENSO</span>, and attempt to distinguish the precipitation signal from basal mass balance due to changing CDW inflows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28096384','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28096384"><span>Holocene <span class="hlt">ENSO</span>-related cyclic storms recorded by magnetic minerals in speleothems of central China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Zongmin; Feinberg, Joshua M; Xie, Shucheng; Bourne, Mark D; Huang, Chunju; Hu, Chaoyong; Cheng, Hai</p> <p>2017-01-31</p> <p>Extreme hydrologic events such as storms and floods have the potential to severely impact modern human society. However, the frequency of storms and their underlying mechanisms are limited by a paucity of suitable proxies, especially in inland areas. Here we present a record of speleothem magnetic minerals to reconstruct paleoprecipitation, including storms, in the eastern Asian monsoon area over the last 8.6 ky. The geophysical parameter IRM soft-flux represents the flux of soil-derived magnetic minerals preserved in stalagmite HS4, which we correlate with rainfall amount and intensity. IRM soft-flux exhibits relatively higher values before 6.7 ky and after 3.4 ky and lower values in the intervening period, consistent with regional hydrological changes observed in independent records. Abrupt enhancements in the flux of pedogenic magnetite in the stalagmite agree well with the timing of known regional paleofloods and with equatorial El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) patterns, documenting the occurrence of <span class="hlt">ENSO</span>-related storms in the Holocene. Spectral power analyses reveal that the storms occur on a significant 500-y cycle, coincident with periodic solar activity and <span class="hlt">ENSO</span> variance, showing that reinforced (subdued) storms in central China correspond to reduced (increased) solar activity and amplified (damped) <span class="hlt">ENSO</span>. Thus, the magnetic minerals in speleothem HS4 preserve a record of the cyclic storms controlled by the coupled atmosphere-oceanic circulation driven by solar activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21545666','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21545666"><span>Recent status scores for version 6 of the Addiction Severity Index (<span class="hlt">ASI</span>-6).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cacciola, John S; Alterman, Arthur I; Habing, Brian; McLellan, A Thomas</p> <p>2011-09-01</p> <p>To describe the derivation of recent status scores (RSSs) for version 6 of the Addiction Severity Index (<span class="hlt">ASI</span>-6). 118 <span class="hlt">ASI</span>-6 recent status items were subjected to nonparametric item response theory (NIRT) analyses followed by confirmatory factor analysis (CFA). Generalizability and concurrent validity of the derived scores were determined. A total of 607 recent admissions to variety of substance abuse treatment programs constituted the derivation sample; a subset (n = 252) comprised the validity sample. The <span class="hlt">ASI</span>-6 interview and a validity battery of primarily self-report questionnaires that included at least one measure corresponding to each of the seven <span class="hlt">ASI</span> domains were administered. Nine summary scales describing recent status that achieved or approached both high scalability and reliability were derived; one scale for each of six areas (medical, employment/finances, alcohol, drug, legal, psychiatric) and three scales for the family/social area. Intercorrelations among the RSSs also supported the multi-dimensionality of the <span class="hlt">ASI</span>-6. Concurrent validity analyses yielded strong evidence supporting the validity of six of the RSSs (medical, alcohol, drug, employment, family/social problems, psychiatric). Evidence was weaker for the legal, family/social support and child problems RSSs. Generalizability analyses of the scales to males versus females and whites versus blacks supported the comparability of the findings, with slight exceptions. The psychometric analyses to derive Addiction Severity Index version 6 recent status scores support the multi-dimensionality of the Addiction Severity Index version 6 (i.e. the relative independence of different life functioning areas), consistent with research on earlier editions of the instrument. In general, the Addiction Severity Index version 6 scales demonstrate acceptable scalability, reliability and concurrent validity. While questions remain about the generalizability of some scales to population subgroups, the overall findings</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMPP53A..05A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMPP53A..05A"><span>A Millennial Record of Rainfall And <span class="hlt">ENSO</span> Variability in Stalagmites From a Mid-Ocean Island in the South Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aharon, P.; Rasbury, M. S.; Lambert, W. J.; Ghaleb, B.; Lambert, L.</p> <p>2005-12-01</p> <p>Improved understanding of ocean-atmosphere interactions that control interdecadal <span class="hlt">ENSO</span> variability prompted recently a renewed interest in the acquisition of highly resolved proxy <span class="hlt">ENSO</span> records. Corals possessing annual growth increments have extended the <span class="hlt">ENSO</span> archive several centuries beyond the existing instrumental data but much longer records are needed to constrain the interdecadal periodicities and unravel their underlying causes. To this end, paleoclimate proxies archived in stalagmites from tropical Pacific settings have not been harnessed to the task of <span class="hlt">ENSO</span> paleo-reconstructions although stalagmites elsewhere have offered valuable paleoclimate insights. Here we report the results of an investigation of stalagmites from a water-table cave on Niue Island in the South Pacific (19o 00' S; 169o 50' W) located at the epicenter of oceanic <span class="hlt">ENSO</span>. Century-long instrumental records on Niue provide a frame of reference and indicate that the interannual and interdecadal air temperature variability is negligible but the rainfall is fully engaged in the wheels of <span class="hlt">ENSO</span> such that El-Niño and La-Niña events correspond with droughts and abundant rainfall, respectively. Seasonal monsoon and trade rainfalls exhibit a marked contrast in their oxygen isotope compositions. Rainfall amount governs microbial soil activities resulting in convergent 18O and 13C depletions and enrichments in the drips that are transferred to the calcite stalagmites in the Niuean caves. A detailed study of four actively growing stalagmites whose chronology overlaps with the instrumental records confirms that interannual and decadal-scale <span class="hlt">ENSO</span> variability is clearly expressed in the annual couplets widths and stable oxygen and carbon isotope time-series records of continuous layered stalagmites. Acquisition of a chronology for USM1 stalagmite posed radiometric dating challenges. The U concentration, in the range of 44.2 to 97.5 ppb, is relatively low by comparison with typical stalagmite values</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMGC51D1023F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMGC51D1023F"><span>Evaluation of the impact of <span class="hlt">ENSO</span> on precipitation extremes in southern Brazil considering the ODP phases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Firpo, M. A.; Sansigolo, C. A.</p> <p>2011-12-01</p> <p>One of the most important modes of interannual variability from ocean-atmosphere system is the El Niño/Southern Oscillation - <span class="hlt">ENSO</span>. The Brazil southern region belongs to the Southeast of South America, where there is a strong signal of <span class="hlt">ENSO</span>, especially over the precipitation. This phenomenon can be modulated by low frequency climate patterns, especially the dominant pattern of North Pacific, called Pacific Decadal Oscillation (PDO). Attempting to better understand these interactions, the objective of this study was to investigate the seasonal impact of <span class="hlt">ENSO</span> events over the Southern Brazil precipitation, taking into account the PDO phases. The dataset used in this study, consist of monthly precipitation records of six well distributed stations from southern Brazil (Rio Grande do Sul state). From these series it was calculated a unique index, which was categorized in three classes, in order to obtain the extremes: very below normal precipitation (below the percentile 10), normal precipitation (between percentile 10 and 90) and very above normal precipitation (above the percentile 90). To characterize the <span class="hlt">ENSO</span> events, it was applied the Trenberth (1997) criteria in the index proposed by Bunge and Clarke (2009), which corrects the inconsistencies between the conventional SST index for Niño 3.4 region and the Southern Oscillation Index before 1950, going beyond the incoherence for decadal scale. For PDO, it was used the index proposed by Mantua et al. (1997). Contingency tables were constructed to analyze the seasonal, simultaneous, and 3, 6, 9 and 12 months lagged relationships between <span class="hlt">ENSO</span> events (El Niño, neutral, La Niña), and extreme precipitation anomalies (categories), also considering the PDO phases during the 1913-1999 period. Moreover, a wavelet analysis was used to check the coherency and phase among these 3 times series during the 1913-2006 period. The Contingency Tables analysis showed that, generally, there were more positive (negative) precipitation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ClDy...28..441B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ClDy...28..441B"><span>A recipe for simulating the interannual variability of the Asian summer monsoon and its relation with <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bracco, Annalisa; Kucharski, Fred; Molteni, Franco; Hazeleger, Wilco; Severijns, Camiel</p> <p>2007-04-01</p> <p>This study investigates how accurately the interannual variability over the Indian Ocean basin and the relationship between the Indian summer monsoon and the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) can be simulated by different modelling strategies. With a hierarchy of models, from an atmospherical general circulation model (AGCM) forced by observed SST, to a coupled model with the ocean component limited to the tropical Pacific and Indian Oceans, the role of heat fluxes and of interactive coupling is analyzed. Whenever sea surface temperature anomalies in the Indian basin are created by the coupled model, the inverse relationship between the <span class="hlt">ENSO</span> index and the Indian summer monsoon rainfall is recovered, and it is preserved if the atmospherical model is forced by the SSTs created by the coupled model. If the ocean model domain is limited to the Indian Ocean, changes in the Walker circulation over the Pacific during El-Niño years induce a decrease of rainfall over the Indian subcontinent. However, the observed correlation between <span class="hlt">ENSO</span> and the Indian Ocean zonal mode (IOZM) is not properly modelled and the two indices are not significantly correlated, independently on season. Whenever the ocean domain extends to the Pacific, and <span class="hlt">ENSO</span> can impact both the atmospheric circulation and the ocean subsurface in the equatorial Eastern Indian Ocean, modelled precipitation patterns associated both to <span class="hlt">ENSO</span> and to the IOZM closely resemble the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RvGeo..55.1079S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RvGeo..55.1079S"><span>The Defining Characteristics of <span class="hlt">ENSO</span> Extremes and the Strong 2015/2016 El Niño</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santoso, Agus; Mcphaden, Michael J.; Cai, Wenju</p> <p>2017-12-01</p> <p>The year 2015 was special for climate scientists, particularly for the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) research community, as a major El Niño finally materialized after a long pause since the 1997/1998 extreme El Niño. It was scientifically exciting since, due to the short observational record, our knowledge of an extreme El Niño has been based only on the 1982/1983 and 1997/1998 events. The 2015/2016 El Niño was marked by many environmental disasters that are consistent with what is expected for an extreme El Niño. Considering the dramatic impacts of extreme El Niño, and the risk of a potential increase in frequency of <span class="hlt">ENSO</span> extremes under greenhouse warming, it is timely to evaluate how the recent event fits into our understanding of <span class="hlt">ENSO</span> extremes. Here we provide a review of <span class="hlt">ENSO</span>, its nature and dynamics, and through analysis of various observed key variables, we outline the processes that characterize its extremes. The 2015/2016 El Niño brings a useful perspective into the state of understanding of these events and highlights areas for future research. While the 2015/2016 El Niño is characteristically distinct from the 1982/1983 and 1997/1998 events, it still can be considered as the first extreme El Niño of the 21st century. Its extremity can be attributed in part to unusually warm condition in 2014 and to long-term background warming. In effect, this study provides a list of physically meaningful indices that are straightforward to compute for identifying and tracking extreme <span class="hlt">ENSO</span> events in observations and climate models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6326B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6326B"><span>Different coupled atmosphere-recharge oscillator Low Order Models for <span class="hlt">ENSO</span>: a projection approach.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bianucci, Marco; Mannella, Riccardo; Merlino, Silvia; Olivieri, Andrea</p> <p>2016-04-01</p> <p>El Ninõ-Southern Oscillation (<span class="hlt">ENSO</span>) is a large scale geophysical phenomenon where, according to the celebrated recharge oscillator model (ROM), the Ocean slow variables given by the East Pacific Sea Surface Temperature (SST) and the average thermocline depth (h), interact with some fast "irrelevant" ones, representing mostly the atmosphere (the westerly wind burst and the Madden-Julian Oscillation). The fast variables are usually inserted in the model as an external stochastic forcing. In a recent work (M. Bianucci, "Analytical probability density function for the statistics of the <span class="hlt">ENSO</span> phenomenon: asymmetry and power law tail" Geophysical Research Letters, under press) the author, using a projection approach applied to general deterministic coupled systems, gives a physically reasonable explanation for the use of stochastic models for mimicking the apparent random features of the <span class="hlt">ENSO</span> phenomenon. Moreover, in the same paper, assuming that the interaction between the ROM and the fast atmosphere is of multiplicative type, i.e., it depends on the SST variable, an analytical expression for the equilibrium density function of the anomaly SST is obtained. This expression fits well the data from observations, reproducing the asymmetry and the power law tail of the histograms of the NINÕ3 index. Here, using the same theoretical approach, we consider and discuss different kind of interactions between the ROM and the other perturbing variables, and we take into account also non linear ROM as a low order model for <span class="hlt">ENSO</span>. The theoretical and numerical results are then compared with data from observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48..893I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48..893I"><span>Simulation of different types of <span class="hlt">ENSO</span> impacts on South Asian Monsoon in CCSM4</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Islam, Siraj ul; Tang, Youmin</p> <p>2017-02-01</p> <p>It has been found in observation that there are different types of influences of El Nino Southern Oscillation (<span class="hlt">ENSO</span>) on the South Asian Monsoon (SAM). A correct description and representation of these teleconnections is critical for climate models to simulate and predict SAM. In this study, we examine these teleconnections in NCAR CAM4 and CCSM4 models, including the strength and weakness of these models in preserving different types of <span class="hlt">ENSO</span>-SAM relationships. By using observational and simulation dataset, the composite analysis, based on specific selection criteria, is performed for both SAM rainfall and the eastern equatorial Pacific sea surface temperature (SST) anomalies. Anomalous SAM rainfall is characterized in three different types i.e. the indirect influence of the SST anomalies of preceding winter (DJF-only), direct influence of the SST anomalies of concurrent summer (JJAS-only) and the combined influence of both preceding winter and concurrent summer (DJF&JJAS). The analysis reveals that CAM4 uncoupled simulation can reasonably well reproduce the anomalous SAM rainfall in DJF-only and DJF&JJAS types whereas the model fails to simulate the anomalous rainfall in the JJAS-only type. The better performance of CAM4, particularly in DJF&JJAS type, comes from its realistic simulation of moisture content and thermal contrast. Its failure to preserve the <span class="hlt">ENSO</span>-SAM relationship of JJAS-only type is due to the absence of <span class="hlt">ENSO</span> induced warming in Northern Indian Ocean via atmospheric circulation which is indirectly linked to the lack of air-sea coupling. The role of Indian Ocean in controlling the <span class="hlt">ENSO</span>-SAM teleconnections of the DJF&JJAS type is further investigated using CAM4 sensitivity experiments. It is found that in absence of Indian Ocean SST, the anomalous SAM summer rainfall suppresses in the DJF&JJAS type, suggesting the important modulation by Indian Ocean SST probably through the preceding winter equatorial Pacific SST forcing and the atmospheric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP31A1245L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP31A1245L"><span>Do our reconstructions of <span class="hlt">ENSO</span> have too much low-frequency variability?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loope, G. R.; Overpeck, J. T.</p> <p>2017-12-01</p> <p>Reconstructing the spectrum of Pacific SST variability has proven to be difficult both because of complications with proxy systems such as tree rings and the relatively small number of records from the tropical Pacific. We show that the small number of long coral δ18O and Sr/Ca records has caused a bias towards having too much low-frequency variability in PCR, CPS, and RegEM reconstructions of Pacific variability. This occurs because the individual coral records used in the reconstructions have redder spectra than the shared signal (e.g. <span class="hlt">ENSO</span>). This causes some of the unshared, low-frequency signal from local climate, salinity and possibly coral biology to bleed into the reconstruction. With enough chronologies in a reconstruction, this unshared noise cancels out but the problem is exacerbated in our longest reconstructions where fewer records are available. Coral proxies tend to have more low-frequency variability than SST observations so this problem is smaller but can still be seen in pseudoproxy experiments using observations and reanalysis data. The identification of this low-frequency bias in coral reconstructions helps bring the spectra of <span class="hlt">ENSO</span> reconstructions back into line with both models and observations. Although our analysis is mostly constrained to the 20th century due to lack of sufficient data, we expect that as more long chronologies are developed, the low-frequency signal in <span class="hlt">ENSO</span> reconstructions will be greatly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B33E2116A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B33E2116A"><span>2015-16 <span class="hlt">ENSO</span> Drove Tropical Soil Moisture Dynamics and Methane Fluxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aronson, E. L.; Dierick, D.; Botthoff, J.; Swanson, A. C.; Johnson, R. F.; Allen, M. F.</p> <p>2017-12-01</p> <p>The El Niño/Southern Oscillation Event (<span class="hlt">ENSO</span>) cycle drives large-scale climatic trends globally. Within the new world tropics, El Niño brings dryer weather than the counterpart La Niña. Atmospheric methane growth rates have shown extreme variability over the past three decades. One proposed driver is the proportion of tropical land surface saturated, affecting methane production or consumption. We measured methane flux bimonthly through the transition of 2015-16 <span class="hlt">ENSO</span>. The date of measurement, across El Niño and La Niña within the typical "rainy" and "dry" seasons, to be the most significant driver of methane flux. Soil moisture varied across this time period, and regulated methane flux. During the strong El Niño, extreme dry soil conditions occurred in a typical "rainy" season month reducing soil moisture. Wetter than usual soil conditions appeared during the "rainy" season month of the moderate La Niña. The dry El Niño soils corresponded to greater methane consumption by tropical forest soils, and a reduced local atmospheric column methane concentration. Conversely, the wet La Niña soils had lower methane consumption and higher local atmospheric column methane concentrations. The <span class="hlt">ENSO</span> cycle is a strong driver of tropical terrestrial and wetland soil moisture conditions, and can regulate global atmospheric methane dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.5840..638M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.5840..638M"><span>Assessment of laser ablation techniques in <span class="hlt">a-si</span> technologies for position-sensor development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molpeceres, C.; Lauzurica, S.; Ocana, J. L.; Gandia, J. J.; Urbina, L.; Carabe, J.</p> <p>2005-07-01</p> <p>Laser micromachining of semiconductor and Transparent Conductive Oxides (TCO) materials is very important for the practical applications in photovoltaic industry. In particular, a problem of controlled ablation of those materials with minimum of debris and small heat affected zone is one of the most vital for the successful implementation of laser micromachining. In particular, selective ablation of thin films for the development of new photovoltaic panels and sensoring devices based on amorphous silicon (<span class="hlt">a-Si</span>) is an emerging field, in which laser micromachining systems appear as appropriate tools for process development and device fabrication. In particular, a promising application is the development of purely photovoltaic position sensors. Standard p-i-n or Schottky configurations using Transparent Conductive Oxides (TCO), <span class="hlt">a-Si</span> and metals are especially well suited for these applications, appearing selective laser ablation as an ideal process for controlled material patterning and isolation. In this work a detailed study of laser ablation of a widely used TCO, Indium-tin-oxide (ITO), and <span class="hlt">a-Si</span> thin films of different thicknesses is presented, with special emphasis on the morphological analysis of the generated grooves. The profiles of ablated grooves have been studied in order to determine the best processing conditions, i.e. laser pulse energy and wavelength, and to asses this technology as potentially competitive to standard photolithographic processes. The encouraging results obtained, with well defined ablation grooves having thicknesses in the order of 10 μm both in ITO and <span class="hlt">a-Si</span>, open up the possibility of developing a high-performance double Schottky photovoltaic matrix position sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/902388','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/902388"><span>South Asian Summer Monsoon and Its Relationship with <span class="hlt">ENSO</span> in the IPCC AR4 Simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Annamalai, H; Hamilton, K; Sperber, K R</p> <p></p> <p>In this paper we use the extensive integrations produced for the IPCC Fourth Assessment Report (AR4) to examine the relationship between <span class="hlt">ENSO</span> and the monsoon at interannual and decadal timescales. We begin with an analysis of the monsoon simulation in the 20th century integrations. Six of the 18 models were found to have a reasonably realistic representation of monsoon precipitation climatology. For each of these six models SST and anomalous precipitation evolution along the equatorial Pacific during El Nino events display considerable differences when compared to observations. Out of these six models only four (GFDL{_}CM{_}2.0, GFDL{_}CM{_}2.1, MRI, and MPI{_}ECHAM5) exhibitmore » a robust <span class="hlt">ENSO</span>-monsoon contemporaneous teleconnection, including the known inverse relationship between <span class="hlt">ENSO</span> and rainfall variations over India. Lagged correlations between the all-India rainfall (AIR) index and Nino3.4 SST reveal that three models represent the timing of the teleconnection, including the spring predictability barrier which is manifested as the transition from positive to negative correlations prior to the monsoon onset. Furthermore, only one of these three models (GFDL{_}CM{_}2.1) captures the observed phase lag with the strongest anticorrelation of SST peaking 2-3 months after the summer monsoon, which is partially attributable to the intensity of simulated El Nino itself. We find that the models that best capture the <span class="hlt">ENSO</span>-monsoon teleconnection are those that correctly simulate the timing and location of SST and diabatic heating anomalies in the equatorial Pacific, and the associated changes to the equatorial Walker Circulation during El Nino events. The strength of the AIR-Nino3.4 SST correlation in the model runs waxes and wanes to some degree on decadal timescales. The overall magnitude and timescale for this decadal modulation in most of the models is similar to that seen in observations. However, there is little consistency in the phase among the realizations</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC21A0818B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC21A0818B"><span>Precipitation response to the current <span class="hlt">ENSO</span> variability in a warming world</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonfils, C.; Santer, B. D.; Phillips, T. J.; Marvel, K.; Leung, L.</p> <p>2013-12-01</p> <p>The major triggers of past and recent droughts include large modes of variability, such as <span class="hlt">ENSO</span>, as well as specific and persistent patterns of sea surface temperature anomalies (SSTAs; Hoerling and Kumar, 2003, Shin et al. 2010, Schubert et al. 2009). However, alternative drought initiators are also anticipated in response to increasing greenhouse gases, potentially changing the relative contribution of ocean variability as drought initiator. They include the intensification of the current zonal wet-dry patterns (the thermodynamic mechanism, Held and Soden, 2006), a latitudinal redistribution of global precipitation (the dynamical mechanism, Seager et al. 2007, Seidel et al. 2008, Scheff and Frierson 2008) and a reduction of local soil moisture and precipitation recycling (the land-atmosphere argument). Our ultimate goal is to investigate whether the relative contribution of those mechanisms change over time in response to global warming. In this study, we first perform an EOF analysis of the 1900-1999 time series of observed global SST field and identify a simple <span class="hlt">ENSO</span>-like (ENSOL) mode of SST variability. We show that this mode is well spatially and temporally correlated with observed worldwide regional precipitation and drought variability. We then develop concise metrics to examine the fidelity with which the CMIP5 coupled global climate models (CGCMs) capture this particular <span class="hlt">ENSO</span>-like mode in the current climate, and their ability to replicate the observed teleconnections with precipitation. Based on the CMIP5 model projections of future climate change, we finally analyze the potential temporal variations in ENSOL to be anticipated under further global warming, as well as their associated teleconnections with precipitation (pattern, amplitude, and total response). Overall, our approach allows us to determine what will be the effect of the current <span class="hlt">ENSO</span>-like variability (i.e., as measured with instrumental observations) on precipitation in a warming world. This</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMNG32A..02Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMNG32A..02Z"><span>A delay differential model of <span class="hlt">ENSO</span> variability: parametric instability and the distribution of extremes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaliapin, I.; Ghil, M.; Thompson, S.</p> <p>2007-12-01</p> <p>We consider a Delay Differential Equation (DDE) model for El-Nino Southern Oscillation (<span class="hlt">ENSO</span>) variability. The model combines two key mechanisms that participate in the <span class="hlt">ENSO</span> dynamics: delayed negative feedback and seasonal forcing. Descriptive and metric stability analyses of the model are performed in a complete 3D space of its physically relevant parameters. Existence of two regimes --- stable and unstable --- is reported. The domains of the regimes are separated by a sharp neutral curve in the parameter space. The detailed structure of the neutral curve become very complicated (possibly fractal), and individual trajectories within the unstable region become highly complex (possibly chaotic) as the atmosphere-ocean coupling increases. In the unstable regime, spontaneous transitions in the mean "temperature" (i.e., thermocline depth), period, and extreme annual values occur, for purely periodic, seasonal forcing. This indicates (via the continuous dependence theorem) the existence of numerous unstable solutions responsible for the complex dynamics of the system. In the stable regime, only periodic solutions are found. Our results illustrate the role of the distinct parameters of <span class="hlt">ENSO</span> variability, such as strength of seasonal forcing vs. atmosphere ocean coupling and propagation period of oceanic waves across the Tropical Pacific. The model reproduces, among other phenomena, the Devil's bleachers (caused by period locking) documented in other <span class="hlt">ENSO</span> models, such as nonlinear PDEs and GCMs, as well as in certain observations. We expect such behavior in much more detailed and realistic models, where it is harder to describe its causes as completely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP31A1107F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP31A1107F"><span>Equatorial Precession Drove Mid-Latitude Changes in <span class="hlt">ENSO</span>-Scale Variation in the Earliest Miocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fox, B.; D'Andrea, W. J.; Lee, D. E.; Wilson, G. S.</p> <p>2014-12-01</p> <p>Foulden Maar is an annually laminated lacustrine diatomite deposit from the South Island of New Zealand. The deposit was laid down over ~100 kyr of the latest Oligocene and earliest Miocene, during the peak and deglaciation phase of the Mi-1 Antarctic glaciation event. At this time, New Zealand was located at approximately the same latitude as today (~45°S). Evidence from organic geochemical proxies (δD, δ13C) and physical properties (density, colour) indicates the presence of an 11-kyr cycle at the site. Although it is known that 11-kyr insolation (half-precession) cycles occur between the Tropics, this cycle is rarely seen in sedimentary archives deposited outside the immediate vicinity of the Equator. Records from Foulden Maar correlate well with the amplitude and phase of the modelled equatorial half-precession cycle for the earliest Miocene. High-resolution (50 µm) colour intensity measurements and lamina thickness measurements both indicate the presence of significant <span class="hlt">ENSO</span>-like (2-8 year) variation in the Foulden Maar sediments. Early results from targeted lamina thickness measurements suggest that <span class="hlt">ENSO</span>-band variation is modulated by the 11-kyr cycle, with power in the <span class="hlt">ENSO</span> band increasing during periods of increased insolation at the Equator. This implies that equatorial half-precession had a significant effect on <span class="hlt">ENSO</span>-like variation in the early Miocene, and that this effect was felt as far afield as the mid-latitudes of the Southern Hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50..571Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50..571Z"><span>Influence of surface nudging on climatological mean and <span class="hlt">ENSO</span> feedbacks in a coupled model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Jieshun; Kumar, Arun</p> <p>2018-01-01</p> <p>Studies have suggested that surface nudging could be an efficient way to reconstruct the subsurface ocean variability, and thus a useful method for initializing climate predictions (e.g., seasonal and decadal predictions). Surface nudging is also the basis for climate models with flux adjustments. In this study, however, some negative aspects of surface nudging on climate simulations in a coupled model are identified. Specifically, a low-resolution version of the NCEP Climate Forecast System, version 2 (CFSv2L) is used to examine the influence of nudging on simulations of climatological mean and on the coupled feedbacks during <span class="hlt">ENSO</span>. The effect on <span class="hlt">ENSO</span> feedbacks is diagnosed following a heat budget analysis of mixed layer temperature anomalies. Diagnostics of the climatological mean state indicates that, even though SST biases in all ocean basins, as expected, are eliminated, the fidelity of climatological precipitation, surface winds and subsurface temperature (or the thermocline depth) could be highly ocean basin dependent. This is exemplified by improvements in the climatology of these variables in the tropical Atlantic, but degradations in the tropical Pacific. Furthermore, surface nudging also distorts the dynamical feedbacks during <span class="hlt">ENSO</span>. For example, while the thermocline feedback played a critical role during the evolution of <span class="hlt">ENSO</span> in a free simulation, it only played a minor role in the nudged simulation. These results imply that, even though the simulation of surface temperature could be improved in a climate model with surface nudging, the physics behind might be unrealistic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26634438','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26634438"><span>Dynamical excitation of the tropical Pacific Ocean and <span class="hlt">ENSO</span> variability by Little Ice Age cooling.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rustic, Gerald T; Koutavas, Athanasios; Marchitto, Thomas M; Linsley, Braddock K</p> <p>2015-12-18</p> <p>Tropical Pacific Ocean dynamics during the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) are poorly characterized due to a lack of evidence from the eastern equatorial Pacific. We reconstructed sea surface temperature, El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) activity, and the tropical Pacific zonal gradient for the past millennium from Galápagos ocean sediments. We document a mid-millennium shift (MMS) in ocean-atmosphere circulation around 1500-1650 CE, from a state with dampened <span class="hlt">ENSO</span> and strong zonal gradient to one with amplified <span class="hlt">ENSO</span> and weak gradient. The MMS coincided with the deepest LIA cooling and was probably caused by a southward shift of the intertropical convergence zone. The peak of the MCA (900-1150 CE) was a warm period in the eastern Pacific, contradicting the paradigm of a persistent La Niña pattern. Copyright © 2015, American Association for the Advancement of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MS%26E..335a2055I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MS%26E..335a2055I"><span>The Influence of <span class="hlt">ENSO</span> to the Rainfall Variability in North Sumatra Province</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Irwandi, H.; Pusparini, N.; Ariantono, J. Y.; Kurniawan, R.; Tari, C. A.; Sudrajat, A.</p> <p>2018-04-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is a global phenomenon that affects the variability of rainfall in North Sumatra. The influence of <span class="hlt">ENSO</span> will be different for each region. This review will analyse the influence of <span class="hlt">ENSO</span> activity on seasonal and annual rainfall variability. In this research, North Sumatra Province will be divided into 4 (four) regions based on topographical conditions, such as: East Coast (EC), East Slope (ES), Mountains (MT), and West Coast (WC). The method used was statistical and descriptive analysis. Data used in this research were rainfall data from 15 stations / climate observation posts which spread in North Sumatera region and also anomaly data of Nino 3.4 region from period 1981-2016. The results showed that the active El Niño had an effect on the decreasing the rainfall during the period of DJF, JJA and SON in East Coast, East Slope, and Mountains with the decreasing of average percentage of annual rainfall up to 7%. On the contrary, the active La Nina had an effect on the addition of rainfall during the period DJF and JJA in the East Coast and Mountains with the increasing of average percentage of annual rainfall up to 6%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6666914-prediction-enso-episodes-using-canonical-correlation-analysis','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6666914-prediction-enso-episodes-using-canonical-correlation-analysis"><span>Prediction of <span class="hlt">ENSO</span> episodes using canonical correlation analysis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barnston, A.G.; Ropelewski, C.F.</p> <p></p> <p>Canonical correlation analysis (CCA) is explored as a multivariate linear statistical methodology with which to forecast fluctuations of the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) in real time. CCA is capable of identifying critical sequences of predictor patterns that tend to evolve into subsequent pattern that can be used to form a forecast. The CCA model is used to forecast the 3-month mean sea surface temperature (SST) in several regions of the tropical Pacific and Indian oceans for projection times of 0 to 4 seasons beyond the immediately forthcoming season. The predictor variables, representing the climate situation in the four consecutive 3-monthmore » periods ending at the time of the forecast, are (1) quasi-global seasonal mean sea level pressure (SLP) and (2) SST in the predicted regions themselves. Forecast skill is estimated using cross-validation, and persistence is used as the primary skill control measure. Results indicate that a large region in the eastern equatorial Pacific (120[degrees]-170[degrees] W longitude) has the highest overall predictability, with excellent skill realized for winter forecasts made at the end of summer. CCA outperforms persistence in this region under most conditions, and does noticeably better with the SST included as a predictor in addition to the SLP. It is demonstrated that better forecast performance at the longer lead times would be obtained if some significantly earlier (i.e., up to 4 years) predictor data were included, because the ability to predict the lower-frequency <span class="hlt">ENSO</span> phase changes would increase. The good performance of the current system at shorter lead times appears to be based largely on the ability to predict <span class="hlt">ENSO</span> evolution for events already in progress. The forecasting of the eastern tropical Pacific SST using CCA is now done routinely on a monthly basis for a O-, 1-, and 2-season lead at the Climate Analysis Center.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP33A2068T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP33A2068T"><span>A High-Resolution <span class="hlt">ENSO</span>-Driven Rainfall Record Derived From an Exceptionally Fast Growing Stalagmite From Niue Island (South Pacific)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Troy, S.; Aharon, P.; Lambert, W. J.</p> <p>2012-12-01</p> <p>El Niño-Southern Oscillation's (<span class="hlt">ENSO</span>) dominant control over the present global climate and its unpredictable response to a global warming makes the study of paleo-<span class="hlt">ENSO</span> important. So far corals, spanning the Tropical Pacific Ocean, are the most commonly used geological archives of paleo-<span class="hlt">ENSO</span>. This is because corals typically exhibit high growth rates (>1 cm/yr), and reproduce reliably surface water temperatures at sub-annual resolution. However there are limitations to coral archives because their time span is relatively brief (in the order of centuries), thus far making a long and continuous <span class="hlt">ENSO</span> record difficult to achieve. On the other hand stalagmites from island settings can offer long and continuous records of <span class="hlt">ENSO</span>-driven rainfall. Niue Island caves offer an unusual opportunity to investigate <span class="hlt">ENSO</span>-driven paleo-rainfall because the island is isolated from other large land masses, making it untainted by continental climate artifacts, and its geographical location is within the Tropical Pacific "rain pool" (South Pacific Convergence Zone; SPCZ) that makes the rainfall variability particularly sensitive to the <span class="hlt">ENSO</span> phase switches. We present here a δ18O and δ13C time series from a stalagmite sampled on Niue Island (19°00' S, 169°50' W) that exhibits exceptionally high growth rates (~1.2 mm/yr) thus affording a resolution comparable to corals but for much longer time spans. A precise chronology, dating back to several millennia, was achieved by U/Th dating of the stalagmite. The stalagmite was sampled using a Computer Automated Mill (CAM) at 300 μm increments in order to receive sub-annual resolution (every 3 months) and calcite powders of 50-100 μg weight were analyzed for δ18O and δ13C using a Continuous Flow Isotope Ratio Mass Spectrometer (CF-IRMS). The isotope time series contains variable shifts at seasonal, inter-annual, and inter-decadal periodicities. The δ13C and δ18O yield ranges of -3.0 to -13.0 (‰ VPDB) and -3.2 to -6.2 (‰ VPDB</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000044331','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000044331"><span>On The Bimodality of <span class="hlt">ENSO</span> Cycle Extremes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.</p> <p>2000-01-01</p> <p>On the basis of sea surface temperature in the El Nino 3.4 region (5N.-5S., 120-170W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of <span class="hlt">ENSO</span> extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-months long for El Nino and about 9- and 18-months long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50- mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=The+AND+search+AND+strategy+AND+is%3a+AND+%22information+dissemination%22+OR+%22competency-based+education%22+OR+%22culturally+competent+care%22+OR+%22consumer+health+information%22+OR+%22consumer+advocacy%22+OR+%22knowledge+management%22+OR+%22dissemination+strategy%22+OR+%22knowledge+uptake%22+OR+%22knowledge+transfer%22&id=ED447802','ERIC'); return false;" href="https://eric.ed.gov/?q=The+AND+search+AND+strategy+AND+is%3a+AND+%22information+dissemination%22+OR+%22competency-based+education%22+OR+%22culturally+competent+care%22+OR+%22consumer+health+information%22+OR+%22consumer+advocacy%22+OR+%22knowledge+management%22+OR+%22dissemination+strategy%22+OR+%22knowledge+uptake%22+OR+%22knowledge+transfer%22&id=ED447802"><span><span class="hlt">ASIS</span> 2000: Knowledge Innovations: Celebrating Our Heritage, Designing Our Future. Proceedings of the <span class="hlt">ASIS</span> Annual Meeting (63rd, Chicago, Illinois, November 12-16, 2000). Volume 37.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kraft, Donald H., Ed.</p> <p></p> <p>The 2000 <span class="hlt">ASIS</span> (American Society for Information Science) conference explored knowledge innovation. The tracks in the conference program included knowledge discovery, capture, and creation; classification and representation; information retrieval; knowledge dissemination; and social, behavioral, ethical, and legal aspects. This proceedings is…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171263','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171263"><span>Contrasting Indian Ocean SST Variability With and Without <span class="hlt">ENSO</span> Influence: A Coupled Atmosphere-Ocean GCM Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yu, Jin-Yi; Lau, K. M.</p> <p>2004-01-01</p> <p>In this study, we perform experiments with a coupled atmosphere-ocean general circulation model (CGCM) to examine <span class="hlt">ENSO</span>'s influence on the interannual sea surface temperature (SST) variability of the tropical Indian Ocean. The control experiment includes both the Indian and Pacific Oceans in the ocean model component of the CGCM (the Indo-Pacific Run). The anomaly experiment excludes <span class="hlt">ENSOs</span> influence by including only the Indian Ocean while prescribing monthly-varying climatological SSTs for the Pacific Ocean (the Indian-Ocean Run). In the Indo-Pacific Run, an oscillatory mode of the Indian Ocean SST variability is identified by a multi-channel singular spectral analysis (MSSA). The oscillatory mode comprises two patterns that can be identified with the Indian Ocean Zonal Mode (IOZM) and a basin-wide warming/cooling mode respectively. In the model, the IOZM peaks about 3-5 months after <span class="hlt">ENSO</span> reaches its maximum intensity. The basin mode peaks 8 months after the IOZM. The timing and associated SST patterns suggests that the IOZM is related to <span class="hlt">ENSO</span>, and the basin- wide warming/cooling develops as a result of the decay of the IOZM spreading SST anomalies from western Indian Ocean to the eastern Indian Ocean. In contrast, in the Indian-Ocean Run, no oscillatory modes can be identified by the MSSA, even though the Indian Ocean SST variability is characterized by east-west SST contrast patterns similar to the IOZM. In both control and anomaly runs, IOZM-like SST variability appears to be associated with forcings from fluctuations of the Indian monsoon. Our modeling results suggest that the oscillatory feature of the IOZM is primarily forced by <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50..901W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50..901W"><span>Seasonal <span class="hlt">ENSO</span> phase locking in the Kiel Climate Model: The importance of the equatorial cold sea surface temperature bias</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wengel, C.; Latif, M.; Park, W.; Harlaß, J.; Bayr, T.</p> <p>2018-02-01</p> <p>The El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) is characterized by a seasonal phase locking, with strongest eastern and central equatorial Pacific sea surface temperature (SST) anomalies during boreal winter and weakest SST anomalies during boreal spring. In this study, key feedbacks controlling seasonal <span class="hlt">ENSO</span> phase locking in the Kiel Climate Model (KCM) are identified by employing Bjerknes index stability analysis. A large ensemble of simulations with the KCM is analyzed, where the individual runs differ in either the number of vertical atmospheric levels or coefficients used in selected atmospheric parameterizations. All integrations use the identical ocean model. The ensemble-mean features realistic seasonal <span class="hlt">ENSO</span> phase locking. <span class="hlt">ENSO</span> phase locking is very sensitive to changes in the mean-state realized by the modifications described above. An excessive equatorial cold tongue leads to weak phase locking by reducing the Ekman feedback and thermocline feedback in late boreal fall and early boreal winter. Seasonal <span class="hlt">ENSO</span> phase locking also is sensitive to the shortwave feedback as part of the thermal damping in early boreal spring, which strongly depends on eastern and central equatorial Pacific SST. The results obtained from the KCM are consistent with those from models participating in the Coupled Model Intercomparison Project phase 5 (CMIP5).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016385','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016385"><span>The Response of Lower Atmospheric Ozone to <span class="hlt">ENSO</span> in Aura Measurements and a Chemistry-Climate Simulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Rodriquez, J. M.; Waugh, D. W.; Nielsen, J. E.</p> <p>2012-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is the dominant mode of tropical variability on interannual time scales. <span class="hlt">ENSO</span> appears to extend its influence into the chemical composition of the tropical troposphere. Recent work has revealed an <span class="hlt">ENSO</span>-induced wave-1 anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this feature using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show composition sensitivity in observations from NASA s Aura satellite Microwave Limb Sounder (MLS) and the Tropospheric Emissions Spectrometer (TES) and a simulation to provide insight into the vertical structure of these <span class="hlt">ENSO</span>-induced ozone changes. The ozone changes due to the Quasi-Biennial Oscillation (QBO) in the extra-polar upper troposphere and lower stratosphere in MLS measurements will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP41E..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP41E..05D"><span>Relationship between annual precipitation variability and <span class="hlt">ENSO</span> in Southern California for the Common Era (last 2,000 years)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DU, X.; Hendy, I. L.; Hinnov, L.; Brown, E. T.; Schimmelmann, A.; Pak, D. K.</p> <p>2017-12-01</p> <p>The El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) has a major influence on Southern California's hydroclimate as demonstrated by both historical observations and model simulations. Santa Barbara Basin (SBB) off Southern California preserves a unique varved (i.e. annually laminated) marine sedimentary archive of modern and Holocene hydroclimate variability, notably including the transition from the regionally dry Medieval Climate Anomaly (MCA) to the wetter Little Ice Age (LIA). Here we present sub-annually resolved scanning XRF elemental counts for the last 2,000 years in SBB from core SPR0901-03KC. Titanium (associated with silicate minerals) is delivered more efficiently to SBB sediments during times of enhanced river flow and in the Mediterranean climate of Southern California, river flow only occurs after precipitation. The Ti record suggests that the precipitation frequency was reduced during the MCA except for a pluvial episode at CE 1075-1121, but increased during the LIA. Time series analysis of Ti counts indicates <span class="hlt">ENSO</span> variability robustly increased during the intervals CE 450-520, 650-720, 980-1150, 1380-1550 and 1720-1750, and experienced relatively quiescent intervals between CE 50-150, 250-400, 550-650, 750-950, 1150-1280 and 1580-1620. Generally the LIA in Southern California is characterized by more active <span class="hlt">ENSO</span> variability with long periodicities (4-7 yr) and multi-decadal variability (54 yr). MCA drought episodes were associated with less active <span class="hlt">ENSO</span>. Active <span class="hlt">ENSO</span> variability in Southern California during the last 2,000 years coincided with reconstructed southward migration of the Intertropical Convergence Zone (ITCZ) suggesting the ITCZ may play a role in the waxing and waning of <span class="hlt">ENSO</span> teleconnections between the central Pacific and the west coast of North America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130014807','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130014807"><span>Assessment of the APCC Coupled MME Suite in Predicting the Distinctive Climate Impacts of Two Flavors of <span class="hlt">ENSO</span> during Boreal Winter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jeong, Hye-In; Lee, Doo Young; Karumuri, Ashok; Ahn, Joong-Bae; Lee, June-Yi; Luo, Jing-Jia; Schemm, Jae-Kyung E.; Hendon, Harry H.; Braganza, Karl; Ham, Yoo-Geun</p> <p>2012-01-01</p> <p>Forecast skill of the APEC Climate Center (APCC) Multi-Model Ensemble (MME) seasonal forecast system in predicting two main types of El Nino-Southern Oscillation (<span class="hlt">ENSO</span>), namely canonical (or cold tongue) and Modoki <span class="hlt">ENSO</span>, and their regional climate impacts is assessed for boreal winter. The APCC MME is constructed by simple composite of ensemble forecasts from five independent coupled ocean-atmosphere climate models. Based on a hindcast set targeting boreal winter prediction for the period 19822004, we show that the MME can predict and discern the important differences in the patterns of tropical Pacific sea surface temperature anomaly between the canonical and Modoki <span class="hlt">ENSO</span> one and four month ahead. Importantly, the four month lead MME beats the persistent forecast. The MME reasonably predicts the distinct impacts of the canonical <span class="hlt">ENSO</span>, including the strong winter monsoon rainfall over East Asia, the below normal rainfall and above normal temperature over Australia, the anomalously wet conditions across the south and cold conditions over the whole area of USA, and the anomalously dry conditions over South America. However, there are some limitations in capturing its regional impacts, especially, over Australasia and tropical South America at a lead time of one and four months. Nonetheless, forecast skills for rainfall and temperature over East Asia and North America during <span class="hlt">ENSO</span> Modoki are comparable to or slightly higher than those during canonical <span class="hlt">ENSO</span> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy..tmp...75Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy..tmp...75Z"><span>On the relationship between <span class="hlt">ENSO</span> and tropical cyclones in the western North Pacific during the boreal summer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Haikun; Wang, Chunzai</p> <p>2018-02-01</p> <p>The present paper uses the satellite era data from 1979 to 2015 to examine the relationship between El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and tropical cyclones (TCs) in the western North Pacific (WNP) during the boreal summer from June to August. It is found that WNP TC variability is characterized by two major feature changes: (1) a significant reduction of the TC number since 1998 and (2) a stronger interannual relationship between <span class="hlt">ENSO</span> and TCs since 1998. Results suggested that such changes are largely due to the synergy effects of a shifting <span class="hlt">ENSO</span> and the Pacific climate regime shift. Since 1998 with a cool Pacific decadal oscillation phase switching from a warm phase, more La Niña and central Pacific (CP) El Niño events occur. The decreased low-level relative vorticity and increased vertical wind shear during 1998-2015 compared to 1979-1997 are responsible for the TC reduction. The stronger interannual relationship between <span class="hlt">ENSO</span> and TCs since 1998 is closely associated the change of CP sea surface temperature. It enhances the associations of environmental factors including vertical wind shear and mid-level relative humidity with TCs and thus increases the interannual relationship between <span class="hlt">ENSO</span> and TCs. These two feature changes also manifest in the mean TC genesis location, with a northwestward shift of the TC genesis location during 1998-2015 and an increased relation to El Niño Modoki index since 1998. This study has an important implication for TC outlooks in the WNP based on climate predictions and projections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdAtS..31..344F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdAtS..31..344F"><span>Interference of the East Asian winter monsoon in the impact of <span class="hlt">ENSO</span> on the East Asian summer monsoon in decaying phases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, Juan; Chen, Wen</p> <p>2014-03-01</p> <p>The variability of the East Asian winter monsoon (EAWM) can be divided into an <span class="hlt">ENSO</span>-related part (EAWMEN) and an <span class="hlt">ENSO</span>-unrelated part (EAWMres). The influence of EAWMres on the <span class="hlt">ENSO</span>-East Asian summer monsoon (EASM) relationship in the decaying stages of <span class="hlt">ENSO</span> is investigated in the present study. To achieve this, <span class="hlt">ENSO</span> is divided into four groups based on the EAWMres: (1) weak EAWMres-El Niño (WEAWMres-EN); (2) strong EAWMres-El Niño (SEAWMres- EN); (3) weak EAWMres-La Niña (WEAWMres-LN); (4) strong EAWMres-La Niña (SEAWMres-LN). Composite results demonstrate that the EAWMres may enhance the atmospheric responses over East Asia to <span class="hlt">ENSO</span> for WEAWMres-EN and SEAWMres-LN. The corresponding low-level anticyclonic (cyclonic) anomalies over the western North Pacific (WNP) associated with El Niño (La Niña) tend to be strong. Importantly, this feature may persist into the following summer, causing abundant rainfall in northern China for WEAWMres-EN cases and in southwestern China for SEAWMres-LN cases. In contrast, for the SEAWMres-EN and WEAWMres-LN groups, the EAWMres tends to weaken the atmospheric circulation anomalies associated with El Niño or La Niña. In these cases, the anomalous WNP anticyclone or cyclone tend to be reduced and confined to lower latitudes, which results in deficient summer rainfall in northern China for SEAWMres-EN and in southwestern China for WEAWMres-LN. Further study suggests that anomalous EAWMres may have an effect on the extra-tropical sea surface temperature anomaly, which persists into the ensuing summer and may interfere with the influences of <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000034198','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000034198"><span>Intrinsic Coupled Ocean-Atmosphere Modes of the Asian Summer Monsoon: A Re-assessment of Monsoon-<span class="hlt">ENSO</span> Relationships</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lau, K.-M.; Wu, H. T.</p> <p>2000-01-01</p> <p>Using global rainfall and sea surface temperature (SST) data for the past two decades (1979-1998), we have investigated the intrinsic modes of Asian summer monsoon (ASM) and <span class="hlt">ENSO</span> co-variability. Three recurring ASM rainfall-SST coupled modes were identified. The first is a basin scale mode that features SST and rainfall variability over the entire tropics (including the ASM region), identifiable with those occurring during El Nino or La Nina. This mode is further characterized by a pronounced biennial variation in ASM rainfall and SST associated with fluctuations of the anomalous Walker circulation that occur during El Nino/La Nina transitions. The second mode comprises mixed regional and basin-scale rainfall and SST signals, with pronounced intraseasonal and interannual variabilities. This mode features a SST pattern associated with a developing La Nina, with a pronounced low level anticyclone in the subtropics of the western Pacific off the coast of East Asia. The third mode depicts an east-west rainfall and SST dipole across the southern equatorial Indian Ocean, most likely stemming from coupled ocean-atmosphere processes within the ASM region. This mode also possesses a decadal time scale and a linear trend, which are not associated with El Nino/La Nina variability. Possible causes of year-to-year rainfall variability over the ASM and sub-regions have been evaluated from a reconstruction of the observed rainfall from singular eigenvectors of the coupled modes. It is found that while basin-scale SST can account for portions of ASM rainfall variability during <span class="hlt">ENSO</span> events (up to 60% in 1998), regional processes can accounts up to 20-25% of the rainfall variability in typical non-<span class="hlt">ENSO</span> years. Stronger monsoon-<span class="hlt">ENSO</span> relationship tends to occur in the boreal summer immediately preceding a pronounced La Nina, i.e., 1998, 1988 and 1983. Based on these results, we discuss the possible impacts of the ASM on <span class="hlt">ENSO</span> variability via the west Pacific anticyclone and articulate a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.1379A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.1379A"><span>North Pacific decadal variability: insights from a biennial <span class="hlt">ENSO</span> environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Achuthavarier, Deepthi; Schubert, Siegfried D.; Vikhliaev, Yury V.</p> <p>2017-08-01</p> <p>This study examines the mechanisms of the Pacific decadal oscillation (PDO) in the NASA GEOS-5 general circulation model (GCM). Similar to several other state-of-the-art GCMs, the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) simulated by the GEOS-5 has a strong biennial periodicity. Since this is a model bias that precludes a strong role of <span class="hlt">ENSO</span>, it provides a unique environment to assess the other leading mechanisms of North Pacific decadal variability. Despite the biennial <span class="hlt">ENSO</span> periodicity, the model simulates a realistic PDO pattern in the North Pacific that is resolved as the first empirical orthogonal function (EOF) of winter mean sea surface temperature (SST). The spectrum of the PDO indicates no preferred periodicity. The SST anomalies associated with the PDO, particularly its basin wide structure, are primarily forced by the Aleutian low through Ekman transport. The slow geostrophic transport in association with the meridional adjustment of the subtropical gyre is limited to a narrow region in the Kuroshio-Oyashio extension, north of 40°N. The atmosphere's response to the PDO, while weak, projects onto the North Pacific Oscillation (NPO), a meridional dipole in sea level pressure. Both the lack of preferred periodicity and the weak atmospheric response indicate an air-sea coupled oscillation is an unlikely mechanism in this model. In agreement with recent studies, the NPO is correlated with the North Pacific Gyre Oscillation, which is another leading EOF of North Pacific SST variability. The results emphasize the role of atmospheric variability in the North Pacific SST modes, thereby bringing into question the potential for their predictability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20160013299&hterms=insight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinsight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20160013299&hterms=insight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinsight"><span>North Pacific Decadal Variability: Insights from a Biennial <span class="hlt">ENSO</span> Environment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Achuthavarier, Deepthi; Schubert, Siegfried D.; Vikhliaev, Yury V.</p> <p>2016-01-01</p> <p>This study examines the mechanisms of the Pacific decadal oscillation (PDO) in the NASA GEOS-5 general circulation model (GCM). Similar to several other state-of-the-art GCMs, the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) simulated by the GEOS-5 has a strong biennial periodicity. Since this is a model bias that precludes a strong role of <span class="hlt">ENSO</span>, it provides a unique environment to assess the other leading mechanisms of North Pacific decadal variability. Despite the biennial <span class="hlt">ENSO</span> periodicity, the model simulates a realistic PDO pattern in the North Pacific that is resolved as the first empirical orthogonal function (EOF) of winter mean sea surface temperature (SST). The spectrum of the PDO indicates no preferred periodicity. The SST anomalies associated with the PDO, particularly its basin wide structure, are primarily forced by the Aleutian low through Ekman transport. The slow geostrophic transport in association with the meridional adjustment of the subtropical gyre is limited to a narrow region in the Kuroshio-Oyashio extension, north of 40degN. The atmosphere's response to the PDO, while weak, projects onto the North Pacific Oscillation (NPO), a meridional dipole in sea level pressure. Both the lack of preferred periodicity and the weak atmospheric response indicate an air-sea coupled oscillation is an unlikely mechanism in this model. In agreement with recent studies, the NPO is correlated with the North Pacific Gyre Oscillation, which is another leading EOF of North Pacific SST variability. The results emphasize the role of atmospheric variability in the North Pacific SST modes, thereby bringing into question the potential for their predictability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A22E..04Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A22E..04Z"><span>An MJO-Mediated Mechanism to Explain <span class="hlt">ENSO</span> and IOD Impacts on East African Short Rains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaitchik, B. F.; Berhane, F.; Gnanadesikan, A.</p> <p>2015-12-01</p> <p>Previous studies have found that the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) and the Indian Ocean Dipole (IOD) have significant impacts on rainfall over East Africa (EA) during the short rains (Oct-Dec). However, not all <span class="hlt">ENSO</span> and IOD events are associated with significant precipitation anomalies over EA. Our analysis shows that the IOD and <span class="hlt">ENSO</span> influence EA rainfall by modifying the MJO. Composite analysis of rainfall and outgoing longwave radiation data show that the MJO over the Indian Ocean (phases 2 and 3 of the Wheeler and Hendon index) is associated with significant increase in precipitation over EA during El Niño. In La Niña and non-<span class="hlt">ENSO</span> years, the MJO over the Indian Ocean has very weak impacts on EA convection and precipitation. Although previous studies have found that El Niño / La Niña events are associated with anomalous wetness/dryness over EA, the associations are not evident in the absence of the MJO. Similarly, the IOD exhibits strong associations with EA precipitation when there is MJO activity over the Indian Ocean. During the positive phase of the IOD, the MJO over the Indian Ocean has impacts that extend to EA. In the absence of the MJO, however, the IOD shows weak associations with EA precipitation. Furthermore, there are more MJO days in the Indian Ocean during El Niño and positive IOD events, which implies stronger impacts on EA. During La Niña events more MJO days are observed in the Pacific Ocean, favoring subsidence over the western Indian Ocean and dry anomalies over EA. These observations suggest two critical MJO-related questions that must be addressed in order to explain EA short rain variability typically attributed to <span class="hlt">ENSO</span> or IOD: first, how do <span class="hlt">ENSO</span> and IOD modify background conditions in a way that causes Indian Ocean MJO activity to be more strongly connected to EA under El Niño and IOD positive conditions, and second, why is it that El Niño and IOD positive states slow MJO propagation over the Indian Ocean and speed it over</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911248Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911248Y"><span>Oceanic Channel of the IOD-<span class="hlt">ENSO</span> teleconnection over the Indo-Pacific Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Dongliang; Wang, Jing; Zhao, Xia; Zhou, Hui; Xu, Tengfei; Xu, Peng</p> <p>2017-04-01</p> <p>The lag correlations of observations and model simulated data that participate the Coupled Model Intercomparison Project phase-5 (CMIP5) are used to study the precursory teleconnection between the Indian Ocean Dipole (IOD) and the Pacific <span class="hlt">ENSO</span> one year later through the Indonesian seas. The results suggest that Indonesian Throughflow (ITF) play an important role in the IOD-<span class="hlt">ENSO</span> teleconnection. Numerical simulations using a hierarchy of ocean models and climate coupled models have shown that the interannual sea level depressions in the southeastern Indian Ocean during IOD force enhanced ITF to transport warm water of the Pacific warm pool to the Indian Ocean, producing cold subsurface temperature anomalies, which propagate to the eastern equatorial Pacific and induce significant coupled ocean-atmosphere evolution. The teleconnection is found to have decadal variability. Similar decadal variability has also been identified in the historical simulations of the CMIP5 models. The dynamics of the inter-basin teleconnection during the positive phases of the decadal variability are diagnosed to be the interannual variations of the ITF associated with the Indian Ocean Dipole (IOD). During the negative phases, the thermocline in the eastern equatorial Pacific is anomalously deeper so that the sea surface temperature anomalies in the cold tongue are not sensitive to the thermocline depth changes. The IOD-<span class="hlt">ENSO</span> teleconnection is found not affected significantly by the anthropogenic forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.tmp..141B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.tmp..141B"><span>Interannual hydroclimatic variability and the 2009-2011 extreme <span class="hlt">ENSO</span> phases in Colombia: from Andean glaciers to Caribbean lowlands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bedoya-Soto, Juan Mauricio; Poveda, Germán; Trenberth, Kevin E.; Vélez-Upegui, Jorge Julián</p> <p>2018-03-01</p> <p>During 2009-2011, Colombia experienced extreme hydroclimatic events associated with the extreme phases of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Here, we study the dynamics of diverse land-atmosphere phenomena involved in such anomalous events at continental, regional, and local scales. Standardized anomalies of precipitation, 2-m temperature, total column water (TCW), volumetric soil water (VSW), temperature at 925 hPa, surface sensible heat (SSH), latent heat (SLH), evaporation (EVP), and liquid water equivalent thickness (LWET) are analyzed to assess atmosphere-land controls and relationships over tropical South America (TropSA) during 1986-2013 (long term) and 2009-2011 (<span class="hlt">ENSO</span> extreme phases). An assessment of the interannual covariability between precipitation and 2-m temperature is performed using singular value decomposition (SVD) to identify the dominant spatiotemporal modes of hydroclimatic variability over the region's largest river basins (Amazon, Orinoco, Tocantins, Magdalena-Cauca, and Essequibo). <span class="hlt">ENSO</span>, its evolution in time, and strong and consistent spatial structures emerge as the dominant mode of variability. In situ anomalies during both extreme phases of <span class="hlt">ENSO</span> 2009-2011 over the Magdalena-Cauca River basins are linked at the continental scale. The <span class="hlt">ENSO</span>-driven hydroclimatic effects extend from the diurnal cycle to interannual timescales, as reflected in temperature data from tropical glaciers and the rain-snow boundary in the highest peaks of the Central Andes of Colombia to river levels along the Caribbean lowlands of the Magdalena-Cauca River basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70148676','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70148676"><span>Relating large-scale climate variability to local species abundance: <span class="hlt">ENSO</span> forcing and shrimp in Breton Sound, Louisiana, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Piazza, Bryan P.; LaPeyre, Megan K.; Keim, B.D.</p> <p>2010-01-01</p> <p>Climate creates environmental constraints (filters) that affect the abundance and distribution of species. In estuaries, these constraints often result from variability in water flow properties and environmental conditions (i.e. water flow, salinity, water temperature) and can have significant effects on the abundance and distribution of commercially important nekton species. We investigated links between large-scale climate variability and juvenile brown shrimp Farfantepenaeus aztecus abundance in Breton Sound estuary, Louisiana (USA). Our goals were to (1) determine if a teleconnection exists between local juvenile brown shrimp abundance and the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and (2) relate that linkage to environmental constraints that may affect juvenile brown shrimp recruitment to, and survival in, the estuary. Our results identified a teleconnection between winter <span class="hlt">ENSO</span> conditions and juvenile brown shrimp abundance in Breton Sound estuary the following spring. The physical connection results from the impact of <span class="hlt">ENSO</span> on winter weather conditions in Breton Sound (air pressure, temperature, and precipitation). Juvenile brown shrimp abundance effects lagged <span class="hlt">ENSO</span> by 3 mo: lower than average abundances of juvenile brown shrimp were caught in springs following winter El Niño events, and higher than average abundances of brown shrimp were caught in springs following La Niña winters. Salinity was the dominant <span class="hlt">ENSO</span>-forced environmental filter for juvenile brown shrimp. Spring salinity was cumulatively forced by winter river discharge, winter wind forcing, and spring precipitation. Thus, predicting brown shrimp abundance requires incorporating climate variability into models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP33B2362S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP33B2362S"><span><span class="hlt">ENSO</span> variability over the last 2000 years from a sub-decadal lacustrine lipid biomarker record from Isabel Island, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sachse, D.; Romero, L.; Kienel, U.; Haug, G. H.</p> <p>2016-12-01</p> <p><span class="hlt">ENSO</span> is one of the major drivers of inter-annual climate variability and its effects extend far beyond the Tropical Pacific. However, our knowledge about the stability and linearity of <span class="hlt">ENSO</span> teleconnections is limited due to the short temporal coverage of observational data, in particular of well dated paleo-<span class="hlt">ENSO</span> records. Here we present a high-resolution record of rainfall variability on the Pacific coast of Mexico, which today is significantly correlated to <span class="hlt">ENSO</span> variability (NINO 3.4 index), with dryer conditions during an El Niño phase and wetter conditions during a La Niña phase. The lake, situated in a volcanic crater on Isabel Island, is strongly influenced by rainfall intensity, i.e. freshwater and saline sea water input. A halophile bacterial community dominates during dry phases and an algal community dominates in a freshwater lens which develops during the wet season. Specific lipid biomarkers in the sediments indicate the dominant bacterial community (tetrahymanol and long-chain diols, respectively) in an annually laminated sediment core and record the timing and direction of <span class="hlt">ENSO</span> mean state changes. We find the region was dry before 825 AD, indicating dominant El Niño. Between 825 and 950 AD, wetter conditions provide evidence for a dominating La Niña like pattern. During the early Medieval Climate Anomaly (MCA, 925-1100 AD) we reconstruct a dryer (El Niño like) environment, changing into a La Niña dominated pattern, prevailing until 1700 AD. The late Little Ice Age (LIA, 1700-1850AD) was initially dry and changed into a wetter climate at 1750 AD. Afterwards El Niño dominated in the region. The overall pattern of these changes agrees with other paleoclimate records from the Pacific region. However, our well dated (±20 years) high-resolution record identifies a number of short-lived episodes of deviations from this pattern, in particular during the MCA and the LIA. We also find strong similarities in the timing of these episodes with North Pacific</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..153...40P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..153...40P"><span>Late-Holocene vegetation and climate change in Jeju Island, Korea and its implications for <span class="hlt">ENSO</span> influences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Jungjae; Shin, Young Ho; Byrne, Roger</p> <p>2016-12-01</p> <p>Several recent studies suggest the hypothesis that the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is an important factor controlling the Holocene East Asian Monsoon (EAM). However, the mechanism underlying this influence remains unclear due to the lack of high-resolution paleoclimate records from the coast of East Asia. Here, we provide a new record of late Holocene climate change in coastal East Asia based on multi-proxy evidence (pollen, organic content, magnetic susceptibility, grain size) obtained from a sediment core from Jeju Island, South Korea. As Jeju Island is strongly influenced by the Kuroshio flow, our sediment proxy records contain <span class="hlt">ENSO</span> signals from the tropical Pacific. The study area was affected by dry/cool conditions in the western tropical Pacific (WTP) between 4350 and 1920 cal yr BP when El Niños were frequent, and by rapid warming/wetting and forestation since 1920 cal yr BP when La Niñas were more common. Jeju Island was relatively dry/cool between 2100 and 1600, 1300-1200, 1100-1000, 800-650, and 300-50 cal yr BP, as opposed to the Galápagos Islands, which were relatively wet/warm, reflecting the <span class="hlt">ENSO</span>-related negative correlation between eastern and western margins of Pacific. Wet conditions may have prevailed during the early Little Ice Age (LIA) (620-280 cal yr BP) despite consistent cooling. This period of high precipitation may have been associated with the increased landfall of typhoons and with warmer Kuroshio currents under La Niña-like conditions. According to our results, EAM on the East Asian coastal margin was predominantly driven by <span class="hlt">ENSO</span> activity, rather than by the precession effect. Paleoclimatic data from Jeju Island, with its insular position and closeness to warm Kuroshio currents, provide clear evidence of these <span class="hlt">ENSO</span> influences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Electronic+AND+Warfare&id=EJ537936','ERIC'); return false;" href="https://eric.ed.gov/?q=Electronic+AND+Warfare&id=EJ537936"><span>Global Complexity: Information, Chaos, and Control at <span class="hlt">ASIS</span> 1996 Annual Meeting.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jacob, M. E. L.</p> <p>1996-01-01</p> <p>Discusses proceedings of the 1996 <span class="hlt">ASIS</span> (American Society for Information Science) annual meeting in Baltimore (Maryland), including chaos theory; electronic universities; distance education; intellectual property, including information privacy on the Internet; the need for leadership in libraries and information centers; information warfare and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.1393X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.1393X"><span>PDO modulation of the <span class="hlt">ENSO</span> impact on the summer South Asian high</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xue, Xu; Chen, Wen; Chen, Shangfeng; Feng, Juan</p> <p>2018-02-01</p> <p>This study investigates modulation effects of the Pacific decadal oscillation (PDO) on the impact of boreal winter El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on the South Asian high (SAH) variability in the following summer. In the El Niño together with positive PDO (EL/+PDO) or the La Niña together with negative PDO (LA/-PDO) years, boreal winter <span class="hlt">ENSO</span> can influence the following summer SAH activity significantly. The SAH tends to be obviously strengthened (weakened) and located further south (north) during EL/+PDO (LA/-PDO). However, in the El Niño together with negative PDO (EL/-PDO) or the La Niña together with positive PDO (LA/+PDO) years, the influence of <span class="hlt">ENSO</span> on the SAH tends to be weak. The strength and location of SAH are close to those in the climatology of 1950-2011 during the EL/-PDO or the LA/+PDO. Further analysis indicates that the PDO could exert pronounced influence on the <span class="hlt">ENSO</span>-SAH connection via modulating the anomalous Walker circulation and charge effect over the tropical Indian Ocean (TIO). During the EL/+PDO or LA/-PDO, the anomalous Walker circulation associated with El Niño or La Niña is stronger and lasts for a longer time than those during the EL/-PDO or LA/+PDO. This leads to stronger descending (ascending) motion over the Maritime Continent and easterly (westerly) wind anomalies over the eastern Indian Ocean in the EL/+PDO (LA/-PDO), which further exert larger effects on the surface heat fluxes and subsurface ocean dynamical heating process over the Indian Ocean. As such, the induced warm (cold) sea surface temperature anomalies over the Indian Ocean are more significant and larger in the EL/+PDO (LA/-PDO). These larger sea surface temperature anomalies over the TIO could exert a more significant influence on the tropospheric temperature via moisture adjustment, which subsequently results in stronger SAH variability in the EL/+PDO or the LA/-PDO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000032525','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000032525"><span>On the Bimodality of <span class="hlt">ENSO</span> Cycle Extremes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.</p> <p>2000-01-01</p> <p>On the basis of sea surface temperature in the El Nino 3.4 region (5 deg. N.,-5 deg. S., 120-170 deg. W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of <span class="hlt">ENSO</span> extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-mo long for El Nino and about 9- and 18-mo long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50-mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-98PC-1776&hterms=1776&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D1776','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-98PC-1776&hterms=1776&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D1776"><span>The ceremonial transfer of Leonardo, the first MPLM, from <span class="hlt">ASI</span> to NASA</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>Participants pose for a photo at the Space Station Processing Facility ceremony transferring the 'Leonardo' Multipurpose Logistics Module (MPLM) from the Italian Space Agency, Agenzia Spaziale Italiana (<span class="hlt">ASI</span>), to NASA. From left, they are astronaut Jim Voss, European Space Agency astronauts Umberto Guidoni of Italy and Christer Fuglesang of Sweden, NASA International Space Station Program Manager Randy Brinkley, NASA Administrator Daniel S. Goldin, <span class="hlt">ASI</span> President Sergio De Julio and Stephen Francois, director, International Space Station Launch Site Support at KSC. The MPLM, a reusable logistics carrier, will be the primary delivery system used to resupply and return International Space Station cargo requiring a pressurized environment. Leonardo is the first of three MPLM carriers for the International Space Station. It is scheduled to be launched on Space Shuttle Mission STS-100, targeted for April 2000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27565241','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27565241"><span>Association of surgeons in training 40th anniversary conference: Liverpool #<span class="hlt">ASi</span>T2016.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Harries, Rhiannon L; Williams, Adam P; McElnay, Philip J; Gokani, Vimal J</p> <p>2016-11-01</p> <p>The Association of Surgeons in Training (<span class="hlt">ASi</span>T) is a professional body and registered charity working to promote excellence in surgical training for the benefit of junior doctors and patient alike. <span class="hlt">ASi</span>T is independent of the National Health Service (NHS), Surgical Royal Colleges and specialty associations, and represents trainees in all ten surgical specialities. We were delighted to be celebrating our 40th Anniversary Conference in the fantastic city of Liverpool with over 700 delegates in attendance and in the company of many <span class="hlt">ASi</span>T Past Presidents. The conference programme focused on how to overcome threats to training in light of the recent turbulent events associated with the junior doctor contract dispute with inspiring talks from Professor Sir Bruce Keogh, NHS Medical Director and Rt Hon Heidi Alexander MP, Shadow Health Secretary. The other central topic to the conference was 'celebrating excellence in surgical training' and we were thankful to many other high profile speakers who attended to help in this celebration. In addition, over £4000 was distributed between more than 30 prizes and was awarded by the incoming President, Mr Adam Williams, to delegates who presented the highest scoring academic work from over 1200 submitted abstracts. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B51E0465X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B51E0465X"><span>Modeling biogeochemical responses of vegetation to <span class="hlt">ENSO</span>: comparison and analysis on subgrid PFT patches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, M.; Hoffman, F. M.</p> <p>2016-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) is an important interannual climate variability and has significant consequences and impacts on the global biosphere. The responses of vegetation to <span class="hlt">ENSO</span> are highly heterogeneous and generally depend on the biophysical and biochemical characteristics associated with model plant functional types (PFTs). The modeled biogeochemical variables from Earth System Models (ESMs) are generally grid averages consisting of several PFTs within a gridcell, which will lead to difficulties in directly comparing them with site observations and large uncertainties in studying their responses to large scale climate variability. In this study, we conducted a transient <span class="hlt">ENSO</span> simulation for the previoustwo decades from 1995 to 2020 using the DOE ACME v0.3 model. It has a comprehensive terrestrial biogeochemistry model that is fully coupled with a sophisticated atmospheric model with an advanced spectral element dynamical core. The model was driven by the NOAA optimum interpolation sea surface temperature (SST) for contemporary years and CFS v2 nine-month seasonal predicted and reconstructed SST for future years till to 2020. We saved the key biogeochemical variables in the subgrid PFT patches and compared them with site observations directly. Furthermore, we studied the biogeochemical responses of terrestrial vegetation to two largest <span class="hlt">ENSO</span> events (1997-1998 and 2015-2016) for different PFTs. Our results show that it is useful and meaningful to compare and analyze model simulations in subgrid patches. The comparison and analysis not only gave us the details of responses of terrestrial ecosystem to global climate variability under changing climate, but also the insightful view on the model performance on the PFT level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010711','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010711"><span>Two Distinct Roles of Atlantic SSTs in <span class="hlt">ENSO</span> Variability: North Tropical Atlantic SST and Atlantic Nino</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ham, Yoo-Geun; Kug, Jong-Seong; Park, Jong-Yeon</p> <p>2013-01-01</p> <p>Two distinct roles of the Atlantic sea surface temperatures (SSTs), namely, the North Tropical Atlantic (NTA) SST and the Atlantic Nino, on the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) variability are investigated using the observational data from 1980 to 2010 and coupled model experiments. It appears that the NTA SST and the Atlantic Nino can be used as two independent predictors for predicting the development of <span class="hlt">ENSO</span> events in the following season. Furthermore, they are likely to be linked to different types of El Nino events. Specifically, the NTA SST cooling during February, March, and April contributes to the central Pacific warming at the subsequent winter season, while the negative Atlantic Nino event during June, July, and August contributes to enhancing the eastern Pacific warming. The coupled model experiments support these results. With the aid of a lagged inverse relationship, the statistical forecast using two Atlantic indices can successfully predict various <span class="hlt">ENSO</span> indices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45.5095A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45.5095A"><span><span class="hlt">ENSO</span> Transition Asymmetry: Internal and External Causes and Intermodel Diversity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>An, Soon-Il; Kim, Ji-Won</p> <p>2018-05-01</p> <p>El Niño is frequently followed by La Niña, but the opposite case rarely happens. Here we explore a mechanism for such an asymmetrical transition and its future changes. Internally, the asymmetrical response of upper ocean waves against surface wind stress anomaly exerts a primary cause of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) transition asymmetry. Externally, the asymmetrical capacitor effects of both Indian and Atlantic Oceans play some roles in driving the <span class="hlt">ENSO</span> transition asymmetry via the interbasin interactions. The historical runs of Coupled Model Intercomparison Project Phase 5 show that the intermodel transition asymmetry is significantly correlated with the intermodel asymmetry in ocean wave response to surface wind forcing but not with that in the interbasin interactions. In addition, the El Niño-to-La Niña transition tendency was weaker in moderate global warming scenario runs (Representative Concentration Pathway 4.5) while slightly enhanced in strong warming scenario runs (Representative Concentration Pathway 8.5). Similar changes also appeared in the asymmetrical response of ocean waves against the surface wind forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/671953','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/671953"><span>Sensitivity of North American agriculture to <span class="hlt">ENSO</span>-based climate scenarios and their socio-economic consequences: Modeling in an integrated assessment framework</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rosenberg, N.J.; Izaurralde, R.C.; Brown, R.A.</p> <p>1997-09-01</p> <p>A group of Canadian, US and Mexican natural resource specialists, organized by the Pacific Northwest National Laboratory (PNNL) under its North American Energy, Environment and Economy (NA3E) Program, has applied a simulation modeling approach to estimating the impact of <span class="hlt">ENSO</span>-driven climatic variations on the productivity of major crops grown in the three countries. Methodological development is described and results of the simulations presented in this report. EPIC (the Erosion Productivity Impact Calculator) was the agro-ecosystem model selected-for this study. EPIC uses a daily time step to simulate crop growth and yield, water use, runoff and soil erosion among other variables.more » The model was applied to a set of so-called representative farms parameterized through a specially-assembled Geographic Information System (GIS) to reflect the soils, topography, crop management and weather typical of the regions represented. Fifty one representative farms were developed for Canada, 66 for the US and 23 for Mexico. El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) scenarios for the EPIC simulations were created using the historic record of sea-surface temperature (SST) prevailing in the eastern tropical Pacific for the period October 1--September 30. Each year between 1960 and 1989 was thus assigned to an <span class="hlt">ENSO</span> category or state. The <span class="hlt">ENSO</span> states were defined as El Nino (EN, SST warmer than the long-term mean), Strong El Nino (SEN, much warmer), El Viejo (EV, cooler) and Neutral (within {+-}0.5 C of the long-term mean). Monthly means of temperature and precipitation were then calculated at each farm for the period 1960--1989 and the differences (or anomalies) between the means in Neutral years and EN, SEN and EV years determined. The average monthly anomalies for each <span class="hlt">ENSO</span> state were then used to create new monthly statistics for each farm and <span class="hlt">ENSO</span>-state combination. The adjusted monthly statistics characteristic of each <span class="hlt">ENSO</span> state were then used to drive a stochastic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A43D0271K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A43D0271K"><span>Spatiotemporal Variance of Global Horizontal Moisture Transport and the Influence of Strong <span class="hlt">ENSO</span> Events Using ERA-Interim Reanalysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kutta, E. J.; Hubbart, J. A.; Svoma, B. M.; Eichler, T. P.; Lupo, A. R.</p> <p>2016-12-01</p> <p>El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) is well documented as a leading source of seasonal to inter-annual variations in global weather and climate. Strong <span class="hlt">ENSO</span> events have been shown to alter the location and magnitude of Hadley and Walker circulations that maintain equilibrium at tropical latitudes and regulate moisture transport into mid-latitude storm tracks. Broad impacts associated with <span class="hlt">ENSO</span> events include anomalous regional precipitation (ARP) and temperature patterns and subsequent impacts to socioeconomic and human health systems. Potential socioeconomic and human health impacts range from regional changes in water resources and agricultural productivity to local storm water management, particularly in rapidly urbanizing watersheds. Evidence is mounting to suggest that anthropogenic climate change will increase the frequency of heavy precipitation events, which compounds impacts of ARP patterns associated with strong El Nino events. Therefore, the need exists to identify common regional patterns of spatiotemporal variance of horizontal moisture flux (HMF) during months (Oct-Feb) associated with the peak intensity (Oceanic Nino Index [ONI]) of the three strongest El Nino (ONI > µ + 2σ) and La Nina (ONI < µ - σ) events occurring between January 1979 and June 2016. ERA-Interim reanalysis output on model levels was used to quantify spatial and temporal covariance of HMF at 6-hourly resolution before taking the density weighted vertical average. Long term means (LTM; 1979-2015) were quantified and the influence of strong <span class="hlt">ENSO</span> events was assessed by quantifying deviations from the LTM for each respective covariance property during months associated with the selected <span class="hlt">ENSO</span> events. Results reveal regions of statistically significant (CI = 0.05) differences from the LTM for the vertically integrated HMF and each covariance quantity. Broader implications of this work include potential for improved seasonal precipitation forecasts at regional scales and subsequent</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMOS31B..02B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMOS31B..02B"><span>Influence of <span class="hlt">ENSO</span> events on the freshwater discharge pattern at Patos Lagoon, Rio Grande do Sul, Brazil</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barros, G. P.; Marques, W. C.</p> <p>2013-05-01</p> <p>The aim of this study is to investigate the influence and importance of <span class="hlt">ENSO</span> events on the control of the freshwater discharge pattern at Patos Lagoon, in timescales longer than one year. For this study it was used freshwater discharge, water levels and South Oscillation Index (SOI) data sets. The Southern Oscillation Index, or SOI, gives an indication of the development and intensity of El Niño or La Niña events in the Pacific Ocean. Sustained negative values of the SOI greater than -8 often indicate El Niño episodes. Sustained positive values of the SOI greater than +8 are typical of a La Niña episode. Cross wavelet technique is applied to examine the coherence and phase between interannual time-series (South Oscillation Index, freshwater discharge and water levels). Over synoptic time scales, wind action is the most effective forcing in Patos Lagoon's circulation. However, at longer time scales (over one year), freshwater discharge becomes the most important forcing, controling the water levels, circulation and other processes. At longer time scales, South America is affected by <span class="hlt">ENSO</span>'s influence. El Niño is the South Oscillation phase where the trade winds are weak, the pressure is low over the eastern Tropical Pacific and high on the west side. The south region of Brazil shows precipitation anomalies associated with the <span class="hlt">ENSO</span> occurrence. The most significant <span class="hlt">ENSO</span> events show a high temporal variability, which may occur in near biannual scales (1.5 - 3 years) or in lower frequencies (3 years - 7 years). The freshwater discharge of the main tributaries and water levels in Patos Lagoon are influenced by <span class="hlt">ENSO</span> on interannual scales (cycles between 3.8 and 6 years). Therefore, El Niño events are associated with high mean values of freshwater discharge and water levels above the mean. On the other hand, La Niña events are associated with low mean values of freshwater discharge and water levels below the mean. These results are consistent with analysis related to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MSAIS..20...43P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MSAIS..20...43P"><span>The INAF contribution to the <span class="hlt">ASI</span> Space Debris program: observational activities.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pupillo, G.; Salerno, E.; Bartolini, M.; Di Martino, M.; Mattana, A.; Montebugnoli, S.; Portelli, C.; Pluchino, S.; Schillirò, F.; Konovalenko, A.; Nabatov, A.; Nechaeva, M.</p> <p></p> <p>Space debris are man made objects orbiting around Earth that pose a serious hazard for both present and future human activities in space. Since 2007 the Istituto Nazionale di Astrofisica (INAF) carried out a number of radar campaigns in the framework of the <span class="hlt">ASI</span> ``Space Debris'' program. The observations were performed by using bi- and multi-static radars, composed of the INAF 32-m Italian radiotelescopes located at Medicina and Noto (used as receivers) and the 70-m parabolic antenna at Evpatoria (Ukraine) used as transmitter. The 32 m Ventspils antenna in Latvia also participated in the last campaign at the end of June 2010. Several kinds of objects in various orbital regions (radar calibrators, rocket upper stages, debris of different sizes) were observed and successfully detected. Some unknown objects were also discovered in LEO during the beam-park sessions. In this paper we describe some results of the INAF-<span class="hlt">ASI</span> space debris research activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED449953.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED449953.pdf"><span>Increasing Cultural Sensitivity of the Addiction Severity Index (<span class="hlt">ASI</span>): An Example with Native Americans in North Dakota. Special Report.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Carise, Deni; McLellan, A. Thomas</p> <p></p> <p>The Addiction Severity Index (<span class="hlt">ASI</span>), used throughout the United States and other countries, is the most widely used assessment tool in the addictions field. It is a semi-structured assessment instrument designed for use with clients for substance abuse treatment. The <span class="hlt">ASI</span> gathers information in seven important areas of a patient's life: medical,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11712115S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11712115S"><span>A 300-year Vietnam hydroclimate and <span class="hlt">ENSO</span> variability record reconstructed from tree ring δ18O</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sano, Masaki; Xu, Chenxi; Nakatsuka, Takeshi</p> <p>2012-06-01</p> <p>A tree ring δ18O chronology is developed for the past 300 years (1705-2004) using 6 cypress trees from northern Vietnam to reconstruct long-term hydroclimatic variations in the summer monsoon season. To the best of our knowledge, this is the first well-replicated tree ringδ18O chronology from Southeast Asia, as well as the longest yet produced. Response analyses reveal that tree ring δ18O is significantly correlated with temperature, precipitation, and the Palmer Drought Severity Index (PDSI) during the period May-October, with highest correlation to the PDSI. Our δ18O chronology accounts for 44% of the PDSI variance, and is in good agreement with a 52-year tree ringδ18O chronology from northern Laos (r = 0.77), indicating that regional hydroclimatic signals are well recorded in the δ18O data. Spatial correlation analyses with global sea surface temperatures suggest that the tropical Pacific plays an important role in modulating hydroclimate over the study region. Further, the δ18O chronology correlates significantly with El Niño-Southern Oscillation (<span class="hlt">ENSO</span>)-related indices, and is therefore used to reconstruct the annual Multivariate <span class="hlt">ENSO</span> Index. Because previously published <span class="hlt">ENSO</span> reconstructions are based mainly on proxy records originating from North America and/or the tropical Pacific, the future development of a tree ringδ18O network from mainland Southeast Asia could lead to an independent and more robust reconstruction of <span class="hlt">ENSO</span> variability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A41H0082T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A41H0082T"><span>Simulation of Relationship between <span class="hlt">ENSO</span> and winter precipitation over Western Himalayas: Application of Regional climate model (RegT-Band)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tiwari, P. R.; Mohanty, U. C.; Dey, S.; Acharaya, N.; Sinha, P.</p> <p>2012-12-01</p> <p>Precipitation over the Western Himalayas region during winter is mainly associated with the passage of midlatitude synoptic systems known as western disturbances (WDs). Recently, many observational and modeling studies reported that the relationship of the Indian southwest monsoon rainfall with El Niño- Southern Oscillation (<span class="hlt">ENSO</span>) has weakened since around 1980. But, in contrast, only very few observational studies are reported so far to examine the relationship between <span class="hlt">ENSO</span> and the winter precipitation over the Western Himalayas region from December to February (DJF). But there is a huge gap of modeling this phenomenon. So keeping in view of the absence of modeling studies, an attempt is made to simulate the relationship between wintertime precipitations associated with large scale global forcing of <span class="hlt">ENSO</span> over the Western Himalayas. In the present study, RegT-Band, a tropical band version of the regional climate model RegCM4 is integrated for a set of 5 El Niño (1986-87, 1991-92, 1997-98, 2002-03, 2009-10) and 4 La Niña (1984-85, 1988-89, 1999-2000, 2007-08) years with the observed sea-surface temperature and lateral boundary condition. The domain extends from 50° S to 50° N and covers the entire tropics at a grid spacing of about 45 km, i.e. it includes lateral boundary forcing only at the southern and northern boundaries. The performance evaluation of the model in capturing the large scale fields followed by <span class="hlt">ENSO</span> response with wintertime precipitation over the Western Himalayas region has been carried out by using National Center for Environmental Prediction (NCEP)-Department of Energy (DOE) reanalysis 2 (NNRP2) data (2.5° x 2.5°) and Aphrodite precipitation data (0.25° x 0.25°). The model is able to delineate the mean circulation associated with <span class="hlt">ENSO</span> over the region during DJF reasonably well and shows strong southwesterly to northwesterly wind flow, which is there in verification analysis also. The vertical structure of the low as well as upper level</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..149a2025T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..149a2025T"><span>Mesoscale Convective Complexes (MCCs) over the Indonesian Maritime Continent during the <span class="hlt">ENSO</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trismidianto; Satyawardhana, H.</p> <p>2018-05-01</p> <p>This study analyzed the mesoscale convective complexes (MCCs) over the Indonesian Maritime Continent (IMC) during the El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) events for the the15-year period from 2001 to 2015. The MCCs identified by infrared satellite imagery that obtained from the Himawari generation satellite data. This study has reported that the frequencies of the MCC occurrences at the El Niño and La Niña were higher than that of neutral conditions during DJF. Peak of MCC occurrences during DJF at La Niña and neutral condition is in February, while El Niño is in January. <span class="hlt">ENSO</span> strongly affects the occurrence of MCC during the DJF season. The existences of the MCC were also accompanied by increased rainfall intensity at the locations of the MCC occurrences for all <span class="hlt">ENSO</span> events. During JJA seasons, the MCC occurrences are always found during neutral conditions, El Niño and La Niña in Indian Ocean. MCC occurring during the JJA season on El Niño and neutral conditions averaged much longer than during the DJF season. In contrast, MCCs occurring in La Niña conditions during the JJA season are more rapidly extinct than during the DJF. It indicates that the influence of MCC during La Niña during the DJF season is stronger than during the JJA season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Image+AND+Mining&pg=2&id=ED447783','ERIC'); return false;" href="https://eric.ed.gov/?q=Image+AND+Mining&pg=2&id=ED447783"><span>Knowledge: Creation, Organization and Use. <span class="hlt">ASIS</span> '99: Proceedings of the American Society for Information Science (<span class="hlt">ASIS</span>) Annual Meeting (62nd, Washington, DC, October 31-November 4, 1999). Volume 36.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Woods, Larry, Ed.</p> <p></p> <p>The 1999 American Society for Information Science (<span class="hlt">ASIS</span>) conference explored current knowledge creation, acquisition, navigation, correlation, retrieval, management, and dissemination practicalities and potentialities, their implementation and impact, and the theories behind the developments. Speakers reviewed processes, technologies, and tools,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12036002','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12036002"><span>Benefit-cost analysis of addiction treatment: methodological guidelines and empirical application using the DATCAP and <span class="hlt">ASI</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>French, Michael T; Salomé, Helena J; Sindelar, Jody L; McLellan, A Thomas</p> <p>2002-04-01</p> <p>To provide detailed methodological guidelines for using the Drug Abuse Treatment Cost Analysis Program (DATCAP) and Addiction Severity Index (<span class="hlt">ASI</span>) in a benefit-cost analysis of addiction treatment. A representative benefit-cost analysis of three outpatient programs was conducted to demonstrate the feasibility and value of the methodological guidelines. Procedures are outlined for using resource use and cost data collected with the DATCAP. Techniques are described for converting outcome measures from the <span class="hlt">ASI</span> to economic (dollar) benefits of treatment. Finally, principles are advanced for conducting a benefit-cost analysis and a sensitivity analysis of the estimates. The DATCAP was administered at three outpatient drug-free programs in Philadelphia, PA, for 2 consecutive fiscal years (1996 and 1997). The <span class="hlt">ASI</span> was administered to a sample of 178 treatment clients at treatment entry and at 7-months postadmission. The DATCAP and <span class="hlt">ASI</span> appear to have significant potential for contributing to an economic evaluation of addiction treatment. The benefit-cost analysis and subsequent sensitivity analysis all showed that total economic benefit was greater than total economic cost at the three outpatient programs, but this representative application is meant to stimulate future economic research rather than justifying treatment per se. This study used previously validated, research-proven instruments and methods to perform a practical benefit-cost analysis of real-world treatment programs. The study demonstrates one way to combine economic and clinical data and offers a methodological foundation for future economic evaluations of addiction treatment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ECSS...74...96O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ECSS...74...96O"><span>Are population dynamics of shorebirds affected by El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) while on their non-breeding grounds in Ecuador?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Hara, Patrick D.; Haase, Ben J. M.; Elner, Robert W.; Smith, Barry D.; Kenyon, Jamie K.</p> <p>2007-08-01</p> <p>Declines in avian populations are a global concern, particularly for species that migrate between Arctic-temperate and tropical locations. Long-term population studies offer opportunities to detect and document ecological effects attributable to long-term climatic cycles such as the El Niño/Southern Oscillation (<span class="hlt">ENSO</span>). In this study, we report possible population-level effects of such climatic cycles on shorebird species that use two non-breeding season sites in Ecuador (Santa Elena peninsula area, near La Libertad). During our 9-year study period (1991/1992-1999/2000), there was a particularly strong <span class="hlt">ENSO</span> warm phase event during 1997/1998. Population trend data for three species of shorebird, Western Sandpipers ( Calidris mauri), Semipalmated Sandpipers ( C. pusilla), and Least Sandpipers ( C. minutilla), indicated abundances generally declined during the 1990s, but there was an increase in the proportion of first-year birds and their abundance in the years following the 1997/1998 <span class="hlt">ENSO</span> warm phase. There was some support for variation in apparent survivorship associated with the onset of the <span class="hlt">ENSO</span> warm phase event in our population models, based on capture-mark-recapture data. Following the 1997/1998 <span class="hlt">ENSO</span> event onset, individuals for all three species were significantly lighter during the non-breeding season ( F1,3789 = 6.6, p = 0.01). Least-squares mean mass (controlling for size, sex and day of capture) for first-year birds dropped significantly more than for adults following <span class="hlt">ENSO</span> (first-year mass loss = 0.69 ± 0.12 g; adult mass loss = 0.34 ± 0.11 g, F1,3789 = 5.31, p = 0.021), and least-squares mean mass dropped most during the period when sandpipers prepare for northward migration by gaining mass and moulting into breeding plumage. Least Sandpipers may have declined the most in mean mass following <span class="hlt">ENSO</span> (0.76 ± 0.19 g), whereas Semipalmated Sandpipers were 0.52 ± 0.12 g lighter, and Western Sandpipers 0.40 ± 0.13 g lighter, but overall variation among</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26ES..116a2063W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26ES..116a2063W"><span>Effect of <span class="hlt">ENSO</span> on the variability of SST and Chlorophyll-a in Java Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wirasatriya, Anindya; Prasetyawan, Indra B.; Triyono, Chandra D.; Muslim; Maslukah, Lilik</p> <p>2018-02-01</p> <p>Sea surface temperature (SST) and chlorophyll-a (Chl-a) are two parameters often used for identifying the marine productivity. Located at the maritime continent, the variability of SST and Chl-a in the Indonesian seas is influenced by El Niño Southern Oscillation (<span class="hlt">ENSO</span>). The previous studies showed that the effect of El Niño tend to decrease SST and increase Chl-a in the areas within the Indonesian seas. Using long time observation of satellite data (2003-2016), it was found different result in Java Sea. Since Java Sea has strong seasonal variability influenced by monsoon wind, the effect of <span class="hlt">ENSO</span> depend on the season. During southeast monsoon season, El Niño (La Niña) tend to increase (decrease) the speed of southeasterly wind cause the decrease or increase of SST. On the contrary, during northwest monsoon season, El Niño (La Niña) tend to decrease (increase) the speed of northwesterly wind cause the increase (decrease) of SST. The dependence of Chl-a on wind speed is only observed in the off shore which exhibit the strong seasonal variation. However, the effect of <span class="hlt">ENSO</span> on the variability of Chl-a is not robust since the effected amplitude is less than the RMSE of Chl-a data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3128H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3128H"><span><span class="hlt">ENSO</span> amplitude changes due to greenhouse warming in CMIP5: Role of mean tropical precipitation in the 20th centur</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ham, Yoo-Geun; Kug, Jong-Seong</p> <p>2017-04-01</p> <p>The relationship between the present-climate climatology and those of <span class="hlt">ENSO</span> amplitude change under global warming in the CMIP5 models is examined. The models with increased <span class="hlt">ENSO</span> amplitude under greenhouse warming tend to simulate a 20th century stronger climatological ITCZ and SPCZ over the central-eastern Pacific that are located further away from the equator during boreal spring. The budget analysis using moisture equation indicates that those climatological differences lead to stronger positive climatological precipitation change over the off-equatorial central-eastern Pacific under greenhouse warming. The stronger positive climatological precipitation change enhances the air-sea coupling strength over the central-eastern Pacific, which results in the increase of the <span class="hlt">ENSO</span> amplitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738276','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738276"><span>Possible shift in the <span class="hlt">ENSO</span>-Indian monsoon rainfall relationship under future global warming</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Azad, Sarita; Rajeevan, M.</p> <p>2016-01-01</p> <p>EI Nino-Southern Oscillation (<span class="hlt">ENSO</span>) and Indian monsoon rainfall are known to have an inverse relationship, which we have observed in the rainfall spectrum exhibiting a spectral dip in 3–5 y period band. It is well documented that El Nino events are known to be associated with deficit rainfall. Our analysis reveals that this spectral dip (3–5 y) is likely to shift to shorter periods (2.5–3 y) in future, suggesting a possible shift in the relationship between <span class="hlt">ENSO</span> and monsoon rainfall. Spectral analysis of future climate projections by 20 Coupled Model Intercomparison project 5 (CMIP5) models are employed in order to corroborate our findings. Change in spectral dip speculates early occurrence of drought events in future due to multiple factors of global warming. PMID:26837459</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JCli...14..730C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JCli...14..730C"><span>Influence of Mean State Changes on the Structure of <span class="hlt">ENSO</span> in a Tropical Coupled GCM.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Codron, Francis; Vintzileos, Augustin; Sadourny, Robert</p> <p>2001-03-01</p> <p>This study examines the response of the climate simulated by the Institut Pierre Simon Laplace tropical Pacific coupled general circulation model to two changes in parameterization: an improved coupling scheme at the coast, and the introduction of a saturation mixing ratio limiter in the water vapor advection scheme, which improves the rainfall distribution over and around orography. The main effect of these modifications is the suppression of spurious upwelling off the South American coast in Northern Hemisphere summer. Coupled feedbacks then extend this warming over the whole basin in an El Niño-like structure, with a maximum at the equator and in the eastern part of the basin. The mean precipitation pattern widens and moves equatorward as the trade winds weaken.This warmer mean state leads to a doubling of the standard deviation of interannual SST anomalies, and to a longer <span class="hlt">ENSO</span> period. The structure of the <span class="hlt">ENSO</span> cycle also shifts from westward propagation in the original simulation to a standing oscillation. The simulation of El Niño thus improves when compared to recent observed events. The study of <span class="hlt">ENSO</span> spatial structure and lagged correlations shows that these changes of El Niño characteristics are caused by both the increase of amplitude and the modification of the spatial structure of the wind stress response to SST anomalies.These results show that both the mean state and variability of the tropical ocean can be very sensitive to biases or forcings, even geographically localized. They may also give some insight into the mechanisms responsible for the changes in <span class="hlt">ENSO</span> characteristics due to decadal variability or climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5406C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5406C"><span>Weakening of the relationship between the Indian Ocean Dipole and the <span class="hlt">ENSO</span> in recent decades</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, Jun-Young; Ham, Yoo-Geun; Kug, Jong-Seong</p> <p>2016-04-01</p> <p>This study reports, on the 20th century the relationship between the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) and the Indian Ocean Dipole (IOD) was weaker then late 1990s. We shows that 15-yr moving correlation between the Nino3.4 index during the December to February (DJF) and IOD index during the September to November (SON) season. At this results we divided previous decades (1979 to 1998) and late decades (1999 to 2014). The correlation coefficient was 0.64 in the previous decades and 0.21 in the late decades. Late decades was suddenly weaker then previous decades. Because, there is a big difference between previous decades and late decades in the <span class="hlt">ENSO</span> regressed precipitation anomaly spatial distribution during the El Nino developing the MAM season. There was existed positive precipitation anomalies over the off-equatorial western Pacific. It was induced the cross-equatorial southerly flow over the eastern Indian Ocean and maritime continent. It means cross-equatorial southerly flow was key point to understanding <span class="hlt">ENSO</span>-IOD coupling system. In addition, using the climate models participated in Coupled Model Intercomparison Project phase 5 (CMIP5) supports the observational results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005QJRMS.131..781T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005QJRMS.131..781T"><span>The role of the basic state in the <span class="hlt">ENSO</span>-monsoon relationship and implications for predictability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turner, A. G.; Inness, P. M.; Slingo, J. M.</p> <p>2005-04-01</p> <p>The impact of systematic model errors on a coupled simulation of the Asian summer monsoon and its interannual variability is studied. Although the mean monsoon climate is reasonably well captured, systematic errors in the equatorial Pacific mean that the monsoon-<span class="hlt">ENSO</span> teleconnection is rather poorly represented in the general-circulation model. A system of ocean-surface heat flux adjustments is implemented in the tropical Pacific and Indian Oceans in order to reduce the systematic biases. In this version of the general-circulation model, the monsoon-<span class="hlt">ENSO</span> teleconnection is better simulated, particularly the lag-lead relationships in which weak monsoons precede the peak of El Niño. In part this is related to changes in the characteristics of El Niño, which has a more realistic evolution in its developing phase. A stronger <span class="hlt">ENSO</span> amplitude in the new model version also feeds back to further strengthen the teleconnection. These results have important implications for the use of coupled models for seasonal prediction of systems such as the monsoon, and suggest that some form of flux correction may have significant benefits where model systematic error compromises important teleconnections and modes of interannual variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdAtS..34.1358Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdAtS..34.1358Z"><span>Influence of the preceding austral summer Southern Hemisphere annular mode on the amplitude of <span class="hlt">ENSO</span> decay</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Fei; Li, Jianping; Ding, Ruiqiang</p> <p>2017-11-01</p> <p>There is increasing evidence of the possible role of extratropical forcing in the evolution of <span class="hlt">ENSO</span>. The Southern Hemisphere Annular Mode (SAM) is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer (December-January-February; DJF) SAM may also influence the amplitude of <span class="hlt">ENSO</span> decay during austral autumn (March-April-May; MAM). The mechanisms associated with this SAM-<span class="hlt">ENSO</span> relationship can be briefly summarized as follows: The SAM is positively (negatively) correlated with SST in the Southern Hemisphere middle (high) latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole (SOD). The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Niño3.4 area. Anomalous trade winds and SST anomalies over the Niño3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling (warming) over the Niño3.4 area followed by the positive (negative) DJF SAM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.3647X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.3647X"><span>A real-time ocean reanalyses intercomparison project in the context of tropical pacific observing system and <span class="hlt">ENSO</span> monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xue, Yan; Wen, C.; Kumar, A.; Balmaseda, M.; Fujii, Y.; Alves, O.; Martin, M.; Yang, X.; Vernieres, G.; Desportes, C.; Lee, T.; Ascione, I.; Gudgel, R.; Ishikawa, I.</p> <p>2017-12-01</p> <p>An ensemble of nine operational ocean reanalyses (ORAs) is now routinely collected, and is used to monitor the consistency across the tropical Pacific temperature analyses in real-time in support of <span class="hlt">ENSO</span> monitoring, diagnostics, and prediction. The ensemble approach allows a more reliable estimate of the signal as well as an estimation of the noise among analyses. The real-time estimation of signal-to-noise ratio assists the prediction of <span class="hlt">ENSO</span>. The ensemble approach also enables us to estimate the impact of the Tropical Pacific Observing System (TPOS) on the estimation of <span class="hlt">ENSO</span>-related oceanic indicators. The ensemble mean is shown to have a better accuracy than individual ORAs, suggesting the ensemble approach is an effective tool to reduce uncertainties in temperature analysis for <span class="hlt">ENSO</span>. The ensemble spread, as a measure of uncertainties in ORAs, is shown to be partially linked to the data counts of in situ observations. Despite the constraints by TPOS data, uncertainties in ORAs are still large in the northwestern tropical Pacific, in the SPCZ region, as well as in the central and northeastern tropical Pacific. The uncertainties in total temperature reduced significantly in 2015 due to the recovery of the TAO/TRITON array to approach the value before the TAO crisis in 2012. However, the uncertainties in anomalous temperature remained much higher than the pre-2012 value, probably due to uncertainties in the reference climatology. This highlights the importance of the long-term stability of the observing system for anomaly monitoring. The current data assimilation systems tend to constrain the solution very locally near the buoy sites, potentially damaging the larger-scale dynamical consistency. So there is an urgent need to improve data assimilation systems so that they can optimize the observation information from TPOS and contribute to improved <span class="hlt">ENSO</span> prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6834435-analysis-enso-episode-comparison','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6834435-analysis-enso-episode-comparison"><span>Analysis of the 1877-78 <span class="hlt">ENSO</span> episode and comparison with 1982-83</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kiladis, G.N.; Diaz, H.F.</p> <p></p> <p>A comparison of the 1877-78 and 1982-83 El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) events was made using monthly and seasonal values of sea surface temperature (SST) and station pressure in the tropics, sea level pressure (SLP) in North America and the North Atlantic, temperature in North America and precipitation in several key areas around the globe. SST anomalies in the eastern tropical Pacific, heavy rains in coastal Peru and extreme pressure anomalies across the Pacific and Indian Oceans during 1877-78 indicate an <span class="hlt">ENSO</span> event of comparable magnitude to that during 1982-83. Both events were also associated with drought conditions in the Indonesianmore » region, India, South Africa, northeastern Brazil and Hawaii. Wintertime teleconnections in the midlatitudes of the Northern Hemisphere were similar in terms of SLP from the North Pacific to Europe, resulting in significantly higher than normal temperatures over most of the US and extreme rains in California.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18359804','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18359804"><span>Differential mechanisms of binding of anti-sigma factors Escherichia coli Rsd and bacteriophage T4 <span class="hlt">Asi</span>A to E. coli RNA polymerase lead to diverse physiological consequences.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sharma, Umender K; Chatterji, Dipankar</p> <p>2008-05-01</p> <p>Anti-sigma factors Escherichia coli Rsd and bacteriophage T4 <span class="hlt">Asi</span>A bind to the essential housekeeping sigma factor, sigma(70), of E. coli. Though both factors are known to interact with the C-terminal region of sigma(70), the physiological consequences of these interactions are very different. This study was undertaken for the purpose of deciphering the mechanisms by which E. coli Rsd and bacteriophage T4 <span class="hlt">Asi</span>A inhibit or modulate the activity of E. coli RNA polymerase, which leads to the inhibition of E. coli cell growth to different amounts. It was found that <span class="hlt">Asi</span>A is the more potent inhibitor of in vivo transcription and thus causes higher inhibition of E. coli cell growth. Measurements of affinity constants by surface plasmon resonance experiments showed that Rsd and <span class="hlt">Asi</span>A bind to sigma(70) with similar affinity. Data obtained from in vivo and in vitro binding experiments clearly demonstrated that the major difference between <span class="hlt">Asi</span>A and Rsd is the ability of <span class="hlt">Asi</span>A to form a stable ternary complex with RNA polymerase. The binding patterns of <span class="hlt">Asi</span>A and Rsd with sigma(70) studied by using the yeast two-hybrid system revealed that region 4 of sigma(70) is involved in binding to both of these anti-sigma factors; however, Rsd interacts with other regions of sigma(70) as well. Taken together, these results suggest that the higher inhibition of E. coli growth by <span class="hlt">Asi</span>A expression is probably due to the ability of the <span class="hlt">Asi</span>A protein to trap the holoenzyme RNA polymerase rather than its higher binding affinity to sigma(70).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2394999','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2394999"><span>Differential Mechanisms of Binding of Anti-Sigma Factors Escherichia coli Rsd and Bacteriophage T4 <span class="hlt">Asi</span>A to E. coli RNA Polymerase Lead to Diverse Physiological Consequences▿</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sharma, Umender K.; Chatterji, Dipankar</p> <p>2008-01-01</p> <p>Anti-sigma factors Escherichia coli Rsd and bacteriophage T4 <span class="hlt">Asi</span>A bind to the essential housekeeping sigma factor, σ70, of E. coli. Though both factors are known to interact with the C-terminal region of σ70, the physiological consequences of these interactions are very different. This study was undertaken for the purpose of deciphering the mechanisms by which E. coli Rsd and bacteriophage T4 <span class="hlt">Asi</span>A inhibit or modulate the activity of E. coli RNA polymerase, which leads to the inhibition of E. coli cell growth to different amounts. It was found that <span class="hlt">Asi</span>A is the more potent inhibitor of in vivo transcription and thus causes higher inhibition of E. coli cell growth. Measurements of affinity constants by surface plasmon resonance experiments showed that Rsd and <span class="hlt">Asi</span>A bind to σ70 with similar affinity. Data obtained from in vivo and in vitro binding experiments clearly demonstrated that the major difference between <span class="hlt">Asi</span>A and Rsd is the ability of <span class="hlt">Asi</span>A to form a stable ternary complex with RNA polymerase. The binding patterns of <span class="hlt">Asi</span>A and Rsd with σ70 studied by using the yeast two-hybrid system revealed that region 4 of σ70 is involved in binding to both of these anti-sigma factors; however, Rsd interacts with other regions of σ70 as well. Taken together, these results suggest that the higher inhibition of E. coli growth by <span class="hlt">Asi</span>A expression is probably due to the ability of the <span class="hlt">Asi</span>A protein to trap the holoenzyme RNA polymerase rather than its higher binding affinity to σ70. PMID:18359804</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP54B..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP54B..01K"><span>High-Resolution Modeling of <span class="hlt">ENSO</span>-Induced Precipitation in the Tropical Andes: Implications for Proxy Interpretation.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kiefer, J.; Karamperidou, C.</p> <p>2017-12-01</p> <p>Clastic sediment flux into high-elevation Andean lakes is controlled by glacial processes and soil erosion caused by high precipitation events, making these lakes suitable archives of past climate. To wit, sediment records from Laguna Pallcacocha in Ecuador have been interpreted as proxies of <span class="hlt">ENSO</span> variability, owing to increased precipitation in the greater region during El Niño events. However, the location of the lake's watershed, the presence of glaciers, and the different impacts of <span class="hlt">ENSO</span> on precipitation in the eastern vs western Andes have challenged the suitability of the Pallcacocha record as an <span class="hlt">ENSO</span> proxy. Here, we employ WRF, a high-resolution regional mesoscale weather prediction model, to investigate the circulation dynamics, sources of moisture, and resulting precipitation response in the L. Pallcacocha region during different flavors of El Niño and La Niña events, and in the presence or absence of ice caps. In patricular, we investigate Eastern Pacific (EP), Central Pacific (CP), coastal El Niño, and La Niña events. We validate the model simulations against spatially interpolated station measurements and reanalysis data. We find that during EP events, moisture is primarily advected from the Pacific, whereas during CP events, moisture primarily originates from the Atlantic. More moisture is available during EP events, which implies higher precipitation rates. Furthermore, we find that precipitation during EP events is mostly non-convective in contrast to primarily convective precipitation during CP events. Finally, a synthesis of the sedimentary record and the EP:CP ratio of accumulated precipitation and specific humidity in the L. Pallcacocha region allows us to assess whether past changes in the relative frequency of the two <span class="hlt">ENSO</span> flavors may have been recorded in paleoclimate archives in this region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49.2531G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49.2531G"><span>Decadal modulation of the <span class="hlt">ENSO</span>-East Asian winter monsoon relationship by the Atlantic Multidecadal Oscillation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geng, Xin; Zhang, Wenjun; Stuecker, Malte F.; Liu, Peng; Jin, Fei-Fei; Tan, Guirong</p> <p>2017-10-01</p> <p>This work investigates the decadal modulation of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>)-East Asian winter monsoon (EAWM) relationship by the Atlantic Multidecadal Oscillation (AMO). A stable <span class="hlt">ENSO</span>-EAWM relationship is found during the positive AMO phase but not during the negative phase. While the impact of El Niño events on the EAWM does not depend on the AMO phase, a different picture is observed for La Niña events. The La Niña boreal winter season coincides with a strengthened EAWM during a positive AMO phase and a weakened EAWM during a negative AMO phase. We suggest that the AMO's modulating effect mainly comprises two pathways that influence <span class="hlt">ENSO</span>'s impact on the EAWM. On one hand, when La Niña coincides with a positive AMO, the warm SST anomalies over the western North Pacific (WNP) are amplified both in intensity and spatial extent, which favors strengthened WNP cyclonic anomalies and an enhanced EAWM. During La Niña with a negative AMO, only very weak SST anomalies occur over the WNP with reduced WNP cyclonic anomalies that are confined to the tropics, thus having little effect on the EAWM. On the other hand, an eastward-propagating Rossby wavetrain across the mid-high latitudes of Eurasia during a warm AMO phase strengthens the Siberian high and thus leads to a strengthened EAWM, while during a cold AMO phase the Siberian high is weakened, leading to a reduced EAWM. In contrast, El Niño and its associated atmospheric responses are relatively strong and stable, independent of the AMO phase. These results carry important implications to the seasonal-to-interannual predictability associated with <span class="hlt">ENSO</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HESS...18.3651O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HESS...18.3651O"><span>Linkages between <span class="hlt">ENSO</span>/PDO signals and precipitation, streamflow in China during the last 100 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ouyang, R.; Liu, W.; Fu, G.; Liu, C.; Hu, L.; Wang, H.</p> <p>2014-09-01</p> <p>This paper investigates the single and combined impacts of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and the Pacific Decadal Oscillation (PDO) on precipitation and streamflow in China over the last century. Results indicate that the precipitation and streamflow overall decrease during El Niño/PDO warm phase periods and increase during La Niña/PDO cool phase periods in the majority of China, although there are regional and seasonal differences. Precipitation and streamflow in the Yellow River basin, Yangtze River basin and Pearl River basin are more significantly influenced by El Niño and La Niña events than is precipitation and streamflow in the Songhua River basin, especially in October and November. Moreover, significant influence of <span class="hlt">ENSO</span> on streamflow in the Yangtze River mainly occurs in summer and autumn while in the Pearl River influence primarily occurs in the winter and spring. The precipitation and streamflow are relatively greater in the warm PDO phase in the Songhua River basin and several parts of the Yellow River basin and relatively less in the Pearl River basin and most parts of Northwest China compared to those in the cool PDO phase, though there is little significance detected by Wilcoxon signed-rank test. When considering the combined influence of <span class="hlt">ENSO</span> and PDO, the responses of precipitation/streamflow are shown to be opposite in northern China and southern China, with <span class="hlt">ENSO</span>-related precipitation/streamflow enhanced in northern China and decreased in southern China during the warm PDO phases, and enhanced in southern China and decreased in northern China during the cool PDO phases. It is hoped that this study will be beneficial for understanding the precipitation/streamflow responses to the changing climate and will correspondingly provide valuable reference for water resources prediction and management across China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...49..391C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...49..391C"><span><span class="hlt">ENSO</span> related SST anomalies and relation with surface heat fluxes over south Pacific and Atlantic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chatterjee, S.; Nuncio, M.; Satheesan, K.</p> <p>2017-07-01</p> <p>The role of surface heat fluxes in Southern Pacific and Atlantic Ocean SST anomalies associated with El Nino Southern Oscillation (<span class="hlt">ENSO</span>) is studied using observation and ocean reanalysis products. A prominent dipole structure in SST anomaly is found with a positive (negative) anomaly center over south Pacific (65S-45S, 120W-70W) and negative (positive) one over south Atlantic (50S-30S, 30W-0E) during austral summer (DJF) of El Nino (LaNina). During late austral spring-early summer (OND) of El Nino (LaNina), anomalous northerly (southerly) meridional moisture transport and a positive (negative) sea level pressure anomaly induces a suppressed (enhanced) latent heat flux from the ocean surface over south Pacific. This in turn results in a shallower than normal mixed layer depth which further helps in development of the SST anomaly. Mixed layer thins further due to anomalous shortwave radiation during summer and a well developed SST anomaly evolves. The south Atlantic pole exhibits exactly opposite characteristics at the same time. The contribution from the surface heat fluxes to mixed layer temperature change is found to be dominant over the advective processes over both the basins. Net surface heat fluxes anomaly is also found to be maximum during late austral spring-early summer period, with latent heat flux having a major contribution to it. The anomalous latent heat fluxes between atmosphere and ocean surface play important role in the growth of observed summertime SST anomaly. Sea-surface height also shows similar out-of-phase signatures over the two basins and are well correlated with the <span class="hlt">ENSO</span> related SST anomalies. It is also observed that the magnitude of <span class="hlt">ENSO</span> related anomalies over the southern ocean are weaker in LaNina years than in El Nino years, suggesting an intensified tropics-high latitude tele-connection during warm phases of <span class="hlt">ENSO</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.A13B0258P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.A13B0258P"><span>Re-reading the IPCC Report: Aerosols, Droughts and <span class="hlt">ENSO</span> Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Potts, K. A.</p> <p>2008-12-01</p> <p>The Technical Summary of Working Group One in the IPCC Fourth Assessment Report states that "changes in aerosols may have affected precipitation and other aspects of the hydrologic cycle more strongly than other anthropogenic forcing agents" and that "Simulations also suggest that absorbing aerosols, particularly black carbon, can reduce the solar radiation reaching the surface and can warm the atmosphere at regional scales, affecting the vertical temperature profile and the large-scale atmospheric circulation". Taking these two statements at face value I first identify eight seasonal, anthropogenic, regional scale, aerosol plumes which now occur each year and then report the correlation of the aerosol optical depth (AOD) of some of these plumes with climate anomalies in the higher latitudes and with <span class="hlt">ENSO</span> events. The eight identified aerosol plumes vary significantly in extent and AOD inter annually. They have also increased in geographic extent and AOD over recent decades as the population in the tropics, the origin of the majority of these plumes, has increased dramatically requiring increased levels of agriculture and commercial activity. I show that: the AOD of the South East Asian Plume, occurring from late July to November, correlates with four characteristics of drought in south eastern Australia; the aerosol index of the Middle East Plume correlates negatively with rainfall in Darfur; and the volume of tephra ejected by volcanoes in south east Asia correlates: negatively with rainfall and water inflows into the Murray River in south eastern Australia; and positively with <span class="hlt">ENSO</span> events over the period 1890/91 to 2006. I conclude that aerosol plumes over south eastern Asia are the cause of drought in south eastern Australia and <span class="hlt">ENSO</span> events and confirm the statements made in the IPCC Report with respect to these aerosol plumes. I propose a new component of surface aerosol radiative forcing, Regional Dimming, which interferes with the seasonal movement of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008NPGeo..15..417G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008NPGeo..15..417G"><span>A delay differential model of <span class="hlt">ENSO</span> variability: parametric instability and the distribution of extremes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghil, M.; Zaliapin, I.; Thompson, S.</p> <p>2008-05-01</p> <p>We consider a delay differential equation (DDE) model for El-Niño Southern Oscillation (<span class="hlt">ENSO</span>) variability. The model combines two key mechanisms that participate in <span class="hlt">ENSO</span> dynamics: delayed negative feedback and seasonal forcing. We perform stability analyses of the model in the three-dimensional space of its physically relevant parameters. Our results illustrate the role of these three parameters: strength of seasonal forcing b, atmosphere-ocean coupling κ, and propagation period τ of oceanic waves across the Tropical Pacific. Two regimes of variability, stable and unstable, are separated by a sharp neutral curve in the (b, τ) plane at constant κ. The detailed structure of the neutral curve becomes very irregular and possibly fractal, while individual trajectories within the unstable region become highly complex and possibly chaotic, as the atmosphere-ocean coupling κ increases. In the unstable regime, spontaneous transitions occur in the mean "temperature" (i.e., thermocline depth), period, and extreme annual values, for purely periodic, seasonal forcing. The model reproduces the Devil's bleachers characterizing other <span class="hlt">ENSO</span> models, such as nonlinear, coupled systems of partial differential equations; some of the features of this behavior have been documented in general circulation models, as well as in observations. We expect, therefore, similar behavior in much more detailed and realistic models, where it is harder to describe its causes as completely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.131.1449J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.131.1449J"><span>Mechanism of <span class="hlt">ENSO</span> influence on the South Asian monsoon rainfall in global model simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joshi, Sneh; Kar, Sarat C.</p> <p>2018-02-01</p> <p>Coupled ocean atmosphere global climate models are increasingly being used for seasonal scale simulation of the South Asian monsoon. In these models, sea surface temperatures (SSTs) evolve as coupled air-sea interaction process. However, sensitivity experiments with various SST forcing can only be done in an atmosphere-only model. In this study, the Global Forecast System (GFS) model at T126 horizontal resolution has been used to examine the mechanism of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) forcing on the monsoon circulation and rainfall. The model has been integrated (ensemble) with observed, climatological and <span class="hlt">ENSO</span> SST forcing to document the mechanism on how the South Asian monsoon responds to basin-wide SST variations in the Indian and Pacific Oceans. The model simulations indicate that the internal variability gets modulated by the SSTs with warming in the Pacific enhancing the ensemble spread over the monsoon region as compared to cooling conditions. Anomalous easterly wind anomalies cover the Indian region both at 850 and 200 hPa levels during El Niño years. The locations and intensity of Walker and Hadley circulations are altered due to <span class="hlt">ENSO</span> SST forcing. These lead to reduction of monsoon rainfall over most parts of India during El Niño events compared to La Niña conditions. However, internally generated variability is a major source of uncertainty in the model-simulated climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/569258-interaction-between-enso-asian-monsoon-coral-record-tropical-climate','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/569258-interaction-between-enso-asian-monsoon-coral-record-tropical-climate"><span>Interaction between the <span class="hlt">ENSO</span> and the Asian monsoon in a coral record of tropical climate</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Charles, C.D.; Hunter, D.E.; Fairbanks, R.G.</p> <p>1997-08-15</p> <p>The oxygen isotopic composition of a banded coral from the western equatorial Indian Ocean provides a 150-year-long history of the relation between the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon and the Asian monsoon. Interannual cycles in the coral time series were found to correlate with Pacific coral and instrumental climate records, suggesting a consistent linkage across ocean basins, despite the changing frequency and amplitude of the <span class="hlt">ENSO</span>. However, decadal variability that is characteristic of the monsoon system also dominates the coral record, which implies important interactions between tropical and midlatitude climate variability. One prominent manifestation of this interaction is the strongmore » amplitude modulation of the quasi-biennial cycle. 26 refs., 4 figs.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1159014-probable-causes-abnormal-ridge-accompanying-california-drought-enso-precursor-anthropogenic-warming-footprint','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1159014-probable-causes-abnormal-ridge-accompanying-california-drought-enso-precursor-anthropogenic-warming-footprint"><span>Probable Causes of the Abnormal Ridge Accompanying the 2013-2014 California Drought: <span class="hlt">ENSO</span> Precursor and Anthropogenic Warming Footprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, S-Y; Hipps, Lawrence; Gillies, Robert R.</p> <p>2014-05-16</p> <p>The 2013-14 California drought was accompanied by an anomalous high-amplitude ridge system. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer, and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a dipole. The dipole and associated circulation pattern is not linked directly with either <span class="hlt">ENSO</span> or Pacific Decadal Oscillation; instead it is correlated with a typemore » of <span class="hlt">ENSO</span> precursor. The connection between the dipole and <span class="hlt">ENSO</span> precursor has become stronger since the 1970s, and this is attributed to increased GHG loading as simulated by the CESM. Therefore, there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013-14, the associated drought and its intensity.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.3220W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.3220W"><span>Probable causes of the abnormal ridge accompanying the 2013-2014 California drought: <span class="hlt">ENSO</span> precursor and anthropogenic warming footprint</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, S.-Y.; Hipps, Lawrence; Gillies, Robert R.; Yoon, Jin-Ho</p> <p>2014-05-01</p> <p>The 2013-2014 California drought was initiated by an anomalous high-amplitude ridge system. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a dipole. The dipole and associated circulation pattern is not linked directly with either El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) or Pacific Decadal Oscillation; instead, it is correlated with a type of <span class="hlt">ENSO</span> precursor. The connection between the dipole and <span class="hlt">ENSO</span> precursor has become stronger since the 1970s, and this is attributed to increased greenhouse gas loading as simulated by the CESM. Therefore, there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013-2014 and the associated drought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ClDy...50.1747L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ClDy...50.1747L"><span>Effects of ocean initial perturbation on developing phase of <span class="hlt">ENSO</span> in a coupled seasonal prediction model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Hyun-Chul; Kumar, Arun; Wang, Wanqiu</p> <p>2018-03-01</p> <p>Coupled prediction systems for seasonal and inter-annual variability in the tropical Pacific are initialized from ocean analyses. In ocean initial states, small scale perturbations are inevitably smoothed or distorted by the observational limits and data assimilation procedures, which tends to induce potential ocean initial errors for the El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) prediction. Here, the evolution and effects of ocean initial errors from the small scale perturbation on the developing phase of <span class="hlt">ENSO</span> are investigated by an ensemble of coupled model predictions. Results show that the ocean initial errors at the thermocline in the western tropical Pacific grow rapidly to project on the first mode of equatorial Kelvin wave and propagate to the east along the thermocline. In boreal spring when the surface buoyancy flux weakens in the eastern tropical Pacific, the subsurface errors influence sea surface temperature variability and would account for the seasonal dependence of prediction skill in the NINO3 region. It is concluded that the <span class="hlt">ENSO</span> prediction in the eastern tropical Pacific after boreal spring can be improved by increasing the observational accuracy of subsurface ocean initial states in the western tropical Pacific.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A22D..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A22D..08S"><span>Reforecasting the 1972-73 <span class="hlt">ENSO</span> Event and the Monsoon Drought Over India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shukla, J.; Huang, B.; Shin, C. S.</p> <p>2016-12-01</p> <p>This paper presents the results of reforcasting the 1972-73 <span class="hlt">ENSO</span> event and the Indian summer monsoon drought using the National Centers for Environmental Prediction (NCEP) Climate Forecast System, version 2 (CFSv2), initialized with the Eu­ropean Centre for Medium-Range Weather Forecasts (ECMWF) global ocean reanalysis version 4, and observation-based land and atmosphere reanalyses. The results of this paper demonstrate that if the modern day climate models were available during the 1970's, even with the limited observations at that time, it should have been possible to predict the 1972-73 <span class="hlt">ENSO</span> event and the associated monsoon drought. These results further suggest the necessity of continuing to develop realistic models of the climate system for accurate and reliable seasonal predictions. This paper also presents a comparison of the 1972-73 El Niño reforecast with the 1997-98 case. As the strongest event during 1958-78, the 1972-73 El Niño is distinguished from the 1997-98 one by its early termination. Initialized in the spring season, the forecast system predicted the onset and development of both events reasonably well, although the reforecasts underestimate the <span class="hlt">ENSO</span> peaking magnitudes. On the other hand, the reforecasts initialized in spring and fall of 1972 persistently predicted lingering wind and SST anomalies in the eastern equatorial Pacific during the spring of 1973. Initialized in fall of 1997, the reforecast also grossly overestimates the peaking westerly wind and warm SST anomalies in the 1997-98 El Niño.In 1972-73, both the Eastern Pacific SST anomalies (for example Nino 3 Index) and the summer monsoon drought over India and the adjoining areas were predicted remarkably well. In contrast, the Eastern Pacific SST anomalies for the 1997-98 event were predicted well, but the normal summer monsoon rainfall over India of 1997 was not predicted by the model. This case study of the 1972-73 event is part of a larger, comprehensive reforecast project</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.V21B1981S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.V21B1981S"><span>Historical series and Near Real Time data analysis produced within <span class="hlt">ASI</span>-SRV project infrastructures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silvestri, M.; Musacchio, M.; Buongiorno, M.; Corradini, S.; Lombardo, V.; Merucci, L.; Spinetti, C.; Sansosti, E.; Pugnaghi, S.; Teggi, S.; Vignoli, S.; Amodio, A.; Dini, L.</p> <p>2009-12-01</p> <p><span class="hlt">ASI</span>-Sistema Rischio Vulcanico (SRV) project is devoted to the development of a pre-operative integrated system managing different Earth Observation (EO) and Non EO data to respond to specific needs of the Italian Civil Protection Department (DPC) and improve the monitoring of Italian active volcanoes. The project provides the capability to maintain a repository where the acquired data are stored and generates products offering a support to risk managers during the different volcanic activity phases. All the products are obtained considering technical choices and developments of <span class="hlt">ASI</span>-SRV based on flexible and scalable modules which take into account also the new coming space sensors and new processing algorithms. An important step of the project development regards the technical and scientific feasibility of the provided products that depends on the data availability, accuracy algorithms and models used in the processing and of course the possibility to validate the results by means of comparison with non-EO independent measurements. The <span class="hlt">ASI</span>-SRV infrastrucutre is based on a distributed client/server architecture which implies that different processors need to ingest data set characterized by a constant and common structure. <span class="hlt">ASI</span>-SRV will develop, in its final version, a centralized HW-SW system located at INGV which will control two complete processing chains, one located at INGV for Optical data, and the other located at IREA for SAR data. The produced results will be disseminated through a WEB-GIS interface which will allow the DPC to overview and assimilate the products in a compatible format respect to their local monitoring system in order to have an immediate use of the provided information. In this paper the first results producing ground deformation measurement via Differential Interferometric SAR (DInSAR) techniques by using SAR data and via the application of the Small BAseline Subset (SBAS) technique developed at IREA, are reported. Moreover different</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AcASn..48...36L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AcASn..48...36L"><span>Modulation of the SSTA decadal variation on <span class="hlt">ENSO</span> events and relationships of SSTA With LOD,SOI, etc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liao, D. C.; Zhou, Y. H.; Liao, X. H.</p> <p>2007-01-01</p> <p>Interannual and decadal components of the length of day (LOD), Southern Oscillation Index (SOI) and Sea Surface Temperature anomaly (SSTA) in Nino regions are extracted by band-pass filtering, and used for research of the modulation of the SSTA on the <span class="hlt">ENSO</span> events. Results show that besides the interannual components, the decadal components in SSTA have strong impacts on monitoring and representing of the <span class="hlt">ENSO</span> events. When the <span class="hlt">ENSO</span> events are strong, the modulation of the decadal components of the SSTA tends to prolong the life-time of the events and enlarge the extreme anomalies of the SST, while the <span class="hlt">ENSO</span> events, which are so weak that they can not be detected by the interannual components of the SSTA, can also be detected with the help of the modulation of the SSTA decadal components. The study further draws attention to the relationships of the SSTA interannual and decadal components with those of LOD, SOI, both of the sea level pressure anomalies (SLPA) and the trade wind anomalies (TWA) in tropic Pacific, and also with those of the axial components of the atmospheric angular momentum (AAM) and oceanic angular momentum (OAM). Results of the squared coherence and coherent phases among them reveal close connections with the SSTA and almost all of the parameters mentioned above on the interannual time scales, while on the decadal time scale significant connections are among the SSTA and SOI, SLPA, TWA, ?3w and ?3w+v as well, and slight weaker connections between the SSTA and LOD, ?3pib and ?3bp</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/535479-seasonal-interannual-variability-atmospheric-heat-sources-moisture-sinks-determined-from-ncep-ncar-reanalysis-part-ii-variability-associated-enso','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/535479-seasonal-interannual-variability-atmospheric-heat-sources-moisture-sinks-determined-from-ncep-ncar-reanalysis-part-ii-variability-associated-enso"><span>Seasonal and interannual variability of atmospheric heat sources and moisture sinks as determined from NCEP/NCAR reanalysis: Part II variability associated with <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tomita, Tomohiko; Yanai, Michio</p> <p></p> <p>The link between the Asian monsoon and the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>) has been demonstrated by a number of studies. This study examines two <span class="hlt">ENSO</span> withdrawal periods and discusses if the Asian monsoon played a role in the differences between them. The 1986 event occurred in the later half of 1986 and retreated in 1988. The 1951 and 1991 events were similar to each other and seemed to continue to the second year after onset and not to have the clear La Nina phase after the events. In the central and eastern Pacific, three variables progress in phase as themore » <span class="hlt">ENSO</span> cycle: sea surface temperature (SST), heat source (Q1), and divergence. Correlation coefficients were calculated and examined with the mean SST on the equator and with the standard deviation of the interannual components of SST. In the central and eastern Pacific, the standard deviation is large and three correlation coefficients are large (over 0.6). Strong air-sea interaction associated with <span class="hlt">ENSO</span> cycle is deduced. In the Indian Ocean and the western Pacific, the correlation coefficients with SST become small rapidly, while the correlation coefficient between Q1 and the divergence is still large. The interannual variability of SSt may not be crucial for those of Q1 and of the divergence in this region because of the potential to generate well organized convection through the high mean SST. This suggests that various factors, such as effects from mid-latitudes, may modify the interannual variability in the region. To examine the effects of the Asian winter monsoon, the anomalous wind field at 850 hPa was investigated. The conditions of the Asian winter monsoon were quite different between the withdrawal periods in the 1986 and 1991 <span class="hlt">ENSO</span> events. The Asian winter monsoon seems to be a factor to modify the <span class="hlt">ENSO</span> cycle, especially in the retreat periods. In addition, the SST from the tropical Indian Ocean to western Pacific may be important for the modulation of the <span class="hlt">ENSO</span>/monsoon system. 9 refs., 10</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22658154-ionic-asi-sub-sub-li-na-rb-stabilized-covalent-sin-bonding-first-principles-calculations','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22658154-ionic-asi-sub-sub-li-na-rb-stabilized-covalent-sin-bonding-first-principles-calculations"><span>Ionic <span class="hlt">ASi</span>{sub 2}N{sub 3} (A=Li, Na, K and Rb) stabilized by the covalent Si–N bonding: First-principles calculations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Huijun; Ren, Jiadong, E-mail: jdren@ysu.edu.cn; Wu, Lailei</p> <p></p> <p>The structural, elastic and electronic properties of LiSi{sub 2}N{sub 3} and its substitutions by Na, K and Rb were investigated through first-principles computations. The expansion of lattice parameters of <span class="hlt">ASi</span>{sub 2}N{sub 3} from Li, Na, K to Rb is found to be determined by the bond angle of Si–N1–Si, which suggests a possible way to improve the lithium ionic conductivity by substitutions. <span class="hlt">ASi</span>{sub 2}N{sub 3} (A=Li, Na, K and Rb) shows the similar elastic behaviors, while the electronic band gap gradually decreases from 5.1 to 3.4 eV from LiSi{sub 2}N{sub 3} to RbSi{sub 2}N{sub 3}. Interestingly, the analysis of electronicmore » structure, crystal orbital Hamiltonian populations and Bader charges shows that the covalence of Si–N bonding is critical for the stability of <span class="hlt">ASi</span>{sub 2}N{sub 3} phase. Among <span class="hlt">ASi</span>{sub 2}N{sub 3} phases, there is a relatively high ionicity in NaSi{sub 2}N{sub 3}; the Si–N bond strength in [Si{sub 2}N{sub 3}]{sup −} net for KSi{sub 2}N{sub 3} and RbSi{sub 2}N{sub 3} is comparable to LiSi{sub 2}N{sub 3}, but stronger than NaSi{sub 2}N{sub 3}. - Graphic abstract: Universal trend of structural and electronic properties in alkaline metal silicon nitrides, <span class="hlt">ASi</span>{sub 2}N{sub 3}, A=Li, Na, K and Rb. - Highlights: • Trend in structure, electronic and mechanical properties of <span class="hlt">ASi</span>{sub 2}N{sub 3} (A=Li-Rb) were predicted. • Lattice expansion of <span class="hlt">ASi</span>{sub 2}N{sub 3} induced by the bond angle of Si–N1–Si was found. • Calculated band gap decreases from 5.1 to 3.4 eV from LiSi{sub 2}N{sub 3} to RbSi{sub 2}N{sub 3}. • Covalent Si–N bonding is critical for the stability of <span class="hlt">ASi</span>{sub 2}N{sub 3}.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.V23E0527P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.V23E0527P"><span>Volcanic Tephra ejected in south eastern Asia is the sole cause of all historic <span class="hlt">ENSO</span> events. This natural aerosol plume has been intensified by an anthropogenic plume in the same region in recent decades which has intensified some <span class="hlt">ENSO</span> events and altered the Southern Oscillation Index characteristics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Potts, K. A.</p> <p>2017-12-01</p> <p><span class="hlt">ENSO</span> events are the most significant perturbation of the climate system. Previous attempts to link <span class="hlt">ENSO</span> with volcanic eruptions typically failed because only large eruptions across the globe which eject tephra into the stratosphere were considered. I analyse all volcanic eruptions in South Eastern (SE) Asia (10ºS to 10ºN and from 90ºE to 160ºE) the most volcanically active area in the world with over 23% of all eruptions in the Global Volcanism Program database occurring here and with 5 volcanoes stated to have erupted nearly continuously for 30 years. SE Asia is also the region where the convective arm of the thermally direct Walker Circulation occurs driven by the intense equatorial solar radiation which creates the high surface temperature. The volcanic tephra plume intercepts some of the solar radiation by absorption/reflection which cools the surface and heats the atmosphere creating a temperature inversion compared to periods without the plume. This reduces convection and causes the Walker Cell and Trade Winds to weaken. This reduced wind speed causes the central Pacific Ocean to warm which creates convection there which further weakens the Walker Cell. With the reduced wind stress the western Pacific warm pool migrates east. This creates an <span class="hlt">ENSO</span> event which continues until the tephra plume reduces, typically when the SE Asian monsoon commences, and convection is re-established over SE Asia and the Pacific warm pool migrates back to the west. Correlations of SE Asian tephra and the <span class="hlt">ENSO</span> indices are typically over 0.80 at p < 0.01 In recent decades the anthropogenic SE Asian aerosol Plume (SEAP) has intensified the volcanic plume in some years from August to November. Using NASA satellite data from 1978 and the NASA MERRA 2 reanalysis dataset I show correlation coefficients typically over 0.70 and up to 0.97 at p < 0.01 between the aerosol optical depth or index and the <span class="hlt">ENSO</span> indices. If two events A and B correlate 5 options are available: 1. A causes B; 2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999BAMS...80.1117C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999BAMS...80.1117C"><span>Interactions with a Weather-Sensitive Decision Maker: A Case Study Incorporating <span class="hlt">ENSO</span> Information into a Strategy for Purchasing Natural Gas.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Changnon, David; Creech, Tamara; Marsili, Nathan; Murrell, William; Saxinger, Michael</p> <p>1999-06-01</p> <p>During the 1997/98 El Niño event, a Northern Illinois University (NIU) faculty member and a group of undergraduate meteorology students interacted with the university's heating plant manager to determine whether climate information and forecast tools could assist him with NIU's natural gas purchase decisions each fall. Based on the El Niño-driven temperature forecasts and information developed by the faculty-directed student group, which indicated that northern Illinois would experience a warmer than average winter (December through March), the manager chose the option to ride the market on a continuous basis, buying incrementally to reduce total natural gas expenditures, rather than lock into a fixed price.To aid this annual decision process, winter El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) classifications, based on sea surface temperature (SST) data measured in the Niño-3 region, were analyzed to determine whether relationships existed between local mean winter temperature and the <span class="hlt">ENSO</span> phenomena during the 1951-97 period. An SST <span class="hlt">ENSO</span> model, which uses the past winter's <span class="hlt">ENSO</span> state along with the SST trends from April through September, was developed to predict the upcoming winter's temperatures (above, near, or below average). The model predicted an 83% chance of a winter experiencing average to below-average temperatures following an El Niño winter, regardless of trend. Those winters following a non-<span class="hlt">ENSO</span> winter with steady or increasing SST trends experienced average or above-average temperatures 79% of the time. These results supported the manager's natural gas decision, which in turn saved NIU approximately $500,000 and aided in the university's decision to hire a full-time applied meteorologist to provide advice on a continuing basis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25097137','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25097137"><span>Image quality of iterative reconstruction in cranial CT imaging: comparison of model-based iterative reconstruction (MBIR) and adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Notohamiprodjo, S; Deak, Z; Meurer, F; Maertz, F; Mueck, F G; Geyer, L L; Wirth, S</p> <p>2015-01-01</p> <p>The purpose of this study was to compare cranial CT (CCT) image quality (IQ) of the MBIR algorithm with standard iterative reconstruction (<span class="hlt">ASi</span>R). In this institutional review board (IRB)-approved study, raw data sets of 100 unenhanced CCT examinations (120 kV, 50-260 mAs, 20 mm collimation, 0.984 pitch) were reconstructed with both <span class="hlt">ASi</span>R and MBIR. Signal-to-noise (SNR) and contrast-to-noise (CNR) were calculated from attenuation values measured in caudate nucleus, frontal white matter, anterior ventricle horn, fourth ventricle, and pons. Two radiologists, who were blinded to the reconstruction algorithms, evaluated anonymized multiplanar reformations of 2.5 mm with respect to depiction of different parenchymal structures and impact of artefacts on IQ with a five-point scale (0: unacceptable, 1: less than average, 2: average, 3: above average, 4: excellent). MBIR decreased artefacts more effectively than <span class="hlt">ASi</span>R (p < 0.01). The median depiction score for MBIR was 3, whereas the median value for <span class="hlt">ASi</span>R was 2 (p < 0.01). SNR and CNR were significantly higher in MBIR than <span class="hlt">ASi</span>R (p < 0.01). MBIR showed significant improvement of IQ parameters compared to <span class="hlt">ASi</span>R. As CCT is an examination that is frequently required, the use of MBIR may allow for substantial reduction of radiation exposure caused by medical diagnostics. • Model-Based iterative reconstruction (MBIR) effectively decreased artefacts in cranial CT. • MBIR reconstructed images were rated with significantly higher scores for image quality. • Model-Based iterative reconstruction may allow reduced-dose diagnostic examination protocols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/883752','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/883752"><span><span class="hlt">ENSO</span> Simulation in Coupled Ocean-Atmosphere Models: Are the Current Models Better?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>AchutaRao, K; Sperber, K R</p> <p></p> <p>Maintaining a multi-model database over a generation or more of model development provides an important framework for assessing model improvement. Using control integrations, we compare the simulation of the El Nino/Southern Oscillation (<span class="hlt">ENSO</span>), and its extratropical impact, in models developed for the 2007 Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report with models developed in the late 1990's (the so-called Coupled Model Intercomparison Project-2 [CMIP2] models). The IPCC models tend to be more realistic in representing the frequency with which <span class="hlt">ENSO</span> occurs, and they are better at locating enhanced temperature variability over the eastern Pacific Ocean. When compared withmore » reanalyses, the IPCC models have larger pattern correlations of tropical surface air temperature than do the CMIP2 models during the boreal winter peak phase of El Nino. However, for sea-level pressure and precipitation rate anomalies, a clear separation in performance between the two vintages of models is not as apparent. The strongest improvement occurs for the modeling groups whose CMIP2 model tended to have the lowest pattern correlations with observations. This has been checked by subsampling the multi-century IPCC simulations in a manner to be consistent with the single 80-year time segment available from CMIP2. Our results suggest that multi-century integrations may be required to statistically assess model improvement of <span class="hlt">ENSO</span>. The quality of the El Nino precipitation composite is directly related to the fidelity of the boreal winter precipitation climatology, highlighting the importance of reducing systematic model error. Over North America distinct improvement of El Nino forced boreal winter surface air temperature, sea-level pressure, and precipitation rate anomalies in the IPCC models occurs. This improvement, is directly proportional to the skill of the tropical El Nino forced precipitation anomalies.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=289439','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=289439"><span>Use of <span class="hlt">ENSO</span> forecasts to select nitrogen fertilizer application strategies for winter</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) has a strong impact on winter crops in Alabama (AL). Wheat is basically grown during winter as cash crop and sometimes also as fodder or grain crop in AL. Thus, it is very necessary to understand the impact of variability in climate factors due to the different ph...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGC41I..01T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGC41I..01T"><span>Climate, <span class="hlt">ENSO</span> and 'Black Swans' over the Last Millennium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, L. G.; Mosley-Thompson, E.; Davis, M. E.; Kenny, D. V.; Lin, P. N.</p> <p>2014-12-01</p> <p>Tropical rainfall patterns influence the lives of billions of people both north and south of the Equator. Evidence of major <span class="hlt">ENSO</span> events such as droughts is often recorded in the oxygen isotopic ratios and aerosol concentrations in tropical ice cores. Here we examine unusual events recorded in three ice cores, two (Quelccaya and Coropuna) in the Southern Hemisphere on the Peruvian Altiplano and the third (Dasuopu) located 22,000 km away on the southern edge of the Tibetan Plateau at the top of the Himalayas. These records suggest that the unique lower and middle tropospheric air flow over chloride (Cl-) and fluoride (F-) enriched areas upwind of the sites during <span class="hlt">ENSO</span> events leads to enhanced deposition of these species on these glaciers. Linkages are demonstrated between ice-core chemistry and drought indicators, changes in lake levels, and <span class="hlt">ENSO</span> and monsoon indices. Two unusual events, in the late 18th and mid-14th Centuries, are marked by abnormally high concentrations of F- and Cl- in at least two of the ice core records. All three records document a drought from 1789 to 1800 CE in which increases in these anionic concentrations reflect the abundance of continental atmospheric dust derived from arid regions upwind of the core sites. The earlier event, apparent only in the Quelccaya and Dasuopu ice cores, begins abruptly in 1343 and tapers off by 1375. The interaction between high frequency El Niños and low frequency shifts in the inter-tropical convergence zone may have resulted in these unusually severe and extended droughts. These "Black Swan" events correspond to historically documented, devastating population disruptions that were in part climate related. The 1789 to 1800 CE event was concurrent with the Doji Bara famine resulting from extended droughts that led to over 600,000 deaths in central India by 1792. Similarly extensive climate disruptions are documented in Central and South America. The mid-14th Century drought is concomitant with major monsoon</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.156..103G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.156..103G"><span>On the relationship between the QBO/<span class="hlt">ENSO</span> and atmospheric temperature using COSMIC radio occultation data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Pan; Xu, Xiaohua; Zhang, Xiaohong</p> <p>2017-04-01</p> <p>In this paper, the spatial patterns and vertical structure of atmospheric temperature anomalies, in both the tropics and the extratropical latitudes, associated with the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and quasi-biennial oscillation (QBO) in the upper troposphere and stratosphere are investigated using global positioning system (GPS) radio occultation (RO) measurements from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Formosa Satellite Mission 3 mission from July 2006 to February 2014. We find that negative correlations between the atmospheric temperature in the tropics and <span class="hlt">ENSO</span> are observed at 17-30 km in the lower stratosphere at a lag of 1-4 months and at a lead of 1 month. Out-of-phase temperature variation is observed in the troposphere over the mid-latitude band and in-phase behaviour is observed in the lower stratosphere. Interestingly, we also find that there is a significant negative correlation at a lag of 1-3 months from 32 km to 40 km in the mid-latitude region of the Northern Hemisphere. The atmospheric temperature variations over mid-latitude regions in both hemispheres are closely related to the QBO. There are also two narrow zones over the subtropical jet zone where the QBO signals are strong in both hemispheres, approximately parallel to the equator. Finally, we develop a new robust index to describe the strength of the <span class="hlt">ENSO</span> and QBO signal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/576797-forecasting-enso-events-neural-network-extended-eof-approach','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/576797-forecasting-enso-events-neural-network-extended-eof-approach"><span>Forecasting <span class="hlt">ENSO</span> events: A neural network-extended EOF approach</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tangang, F.T.; Tang, B.; Monahan, A.H.</p> <p></p> <p>The authors constructed neural network models to forecast the sea surface temperature anomalies (SSTA) for three regions: Nino 4. Nino 3.5, and Nino 3, representing the western-central, the central, and the eastern-central parts of the equatorial Pacific Ocean, respectively. The inputs were the extended empirical orthogonal functions (EEOF) of the sea level pressure (SLP) field that covered the tropical Indian and Pacific Oceans and evolved for a duration of 1 yr. The EEOFs greatly reduced the size of the neural networks from those of the authors` earlier papers using EOFs. The Nino 4 region appeared to be the best forecastedmore » region, with useful skills up to a year lead time for the 1982-93 forecast period. By network pruning analysis and spectral analysis, four important inputs were identified: modes 1, 2, and 6 of the SLP EEOFs and the SSTA persistence. Mode 1 characterized the low-frequency oscillation (LFO, with 4-5-yr period), and was seen as the typical <span class="hlt">ENSO</span> signal, while mode 2, with a period of 2-5 yr, characterized the quasi-biennial oscillation (QBO) plus the LFO. Mode 6 was dominated by decadal and interdecadal variations. Thus, forecasting <span class="hlt">ENSO</span> required information from the QBO, and the decadal-interdecadal oscillations. The nonlinearity of the networks tended to increase with lead time and to become stronger for the eastern regions of the equatorial Pacific Ocean. 35 refs., 14 figs., 4 tabs.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMOS33A1451G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMOS33A1451G"><span><span class="hlt">ENSO</span>-Modulation of Plankton Production in the Northern Gulf of Mexico: A High-Resolution Ocean-Biogeochemical Model Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez, F. A.; Lee, S. K.; Liu, Y.; Hernandez, F., Jr.; Lamkin, J. T.</p> <p>2017-12-01</p> <p>Previous studies have suggested that El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) plays a role in modulating phytoplankton biomass and the reproductive success of marine species in the Gulf of Mexico (GoM). However, characterizations of <span class="hlt">ENSO</span>-related ecosystem responses such as plankton production have not been fully addressed for the region. Here we examine <span class="hlt">ENSO</span> impacts on biogeochemical processes within coastal and open ocean domains in the GoM, using a three dimensional high-resolution ocean-biogeochemical model, forced with historical surface fluxes and river run-off for 1979 - 2014. Enhanced precipitation across southern US during El Nino winter increases freshwater discharge and nutrient load into the GoM mainly via the Mississippi-Atchafalaya River. Those anomalies lead to reduced salinity and greater concentration of dissolved inorganic nitrogen and plankton production in the northern shelf especially during winter. In addition, the frequency of northerly wind anomalies that cool the upper ocean increases during El Nino. The negative surface heat flux anomalies further decrease vertical thermal stratification and thus increase phytoplankton production during early spring in the northern deep GoM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912639W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912639W"><span>Differential imprints of different <span class="hlt">ENSO</span> flavors in global patterns of seasonal precipitation extremes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiedermann, Marc; Siegmund, Jonatan F.; Donges, Jonathan F.; Donner, Reik V.</p> <p>2017-04-01</p> <p>The El Nino Southern Oscillation (<span class="hlt">ENSO</span>) with its positive (El Nino) and negative (La Nina) phases is known to trigger climatic responses in various parts of the Earth, an effect commonly attributed to teleconnectivity. A series of studies has demonstrated that El Nino periods exhibits a relatively broad variety of spatial patterns, which can be classified into two main flavors termed East Pacific (EP, canonical) and Central Pacific (CP, Modoki) El Nino, and that both subtypes can trigger distinct climatic responses like droughts vs. precipitation increases at the regional level. More recently, a similar discrimination of La Nina periods into two different flavors has been reported, and it is reasonable to assume that these different expressions are equally accompanied by differential responses of regional climate variability in particularly affected regions. In this work, we study in great detail the imprints of both types of El Nino and La Nina periods in extremal seasonal precipitation sums during fall (SON), winter (DJF) and spring (MAM) around the peak time of the corresponding <span class="hlt">ENSO</span> phase. For this purpose, we employ a recently developed objective classification of El Nino and La Nina periods into their two respective flavors based on global teleconnectivity patterns in daily surface air temperature anomalies as captured by the associated climate network representations (Wiedermann et al., 2016). In order to study the statistical relevance of the timing of different El Nino and La Nina types on that of seasonal precipitation extremes around the globe (according to the GPCC data set as a reference), we utilize event coincidence analysis (Donges et al., 2016), a new powerful yet conceptually simple and intuitive statistical tool that allows quantifying the degree of simultaneity of distinct events in pairs of time series. Our results provide a comprehensive overview on <span class="hlt">ENSO</span> related imprints in regional seasonal precipitation extremes. We demonstrate that key</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSM.A31A..10R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSM.A31A..10R"><span>Southern Hemisphere Extratropical Cyclones and their Relationship with <span class="hlt">ENSO</span> in springtime</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reboita, M. S.; Ambrizzi, T.; Da Rocha, R.</p> <p>2013-05-01</p> <p>Extratropical cyclones occurrence is associated with the teleconnection mechanisms that produce climate variability. Among these mechanisms we have El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Some works have indicated that during the <span class="hlt">ENSO</span> positive phase there are more cyclogenetic conditions in some parts of the globe as the southwest of South Atlantic Ocean. Therefore, the purpose of this study is to verify if the extratropical cyclones number and location are altered in the different <span class="hlt">ENSO</span> phases in the austral spring over the Southern Hemisphere (SH). The Melbourne University automatic tracking scheme was used to determine the cyclone climatology from 1980 to 2012. All cyclones that appear with lifetime higher or equal to 24 hours in the sea level pressure data from National Centers for Environment Prediction reanalysis I were included in the climatology. El Niño (EN), La Niña (LN) and Neutral (N) years were identified through the Oceanic Niño Index (ONI) from Climate Prediction Center/NOAA. The average number of cyclones in the spring over the SH is similar in the EN (200), N (184) and LN (197) episodes. By latitude bands, during EN episodes the cyclones occurrence reduces in 16% between 70-60 degrees and increases in ~15% between 80-70 and 50-40 degrees. On the other hand, during the LN episodes, the cyclones are 17% more frequent in 50-60 degrees and 22% less frequent in 30-20 degrees. One more detailed analysis of the cyclones trajectory density (that is a statistic product of the tracking algorithm) shows that in the South Atlantic Ocean, near the southeast of South America, the number of cyclones in EN years is higher than in the neutral period and lower than in the LN years. In the Indian Ocean, the EN year is characterized by a cyclones reduction in the west and east sector, near the continents. In the Pacific Ocean, the region southward the New Zealand presents more cyclones occurrence in EN years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP41C1371Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP41C1371Y"><span><span class="hlt">ENSO</span>-Type Signals Recorded in the Late Cretaceous Laminated Sediments of Songliao Basin, Northeast China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, E.; Wang, C.; Hinnov, L. A.; Wu, H.</p> <p>2014-12-01</p> <p>The quasi-periodic, ca. 2-7 year El Niño Southern Oscillation (<span class="hlt">ENSO</span>) phenomenon globally influences the inter-annual variability of temperature and precipitation. Global warming may increase the frequency of extreme <span class="hlt">ENSO</span> events. Although the Cretaceous plate tectonic configuration was different from today, the sedimentary record suggests that <span class="hlt">ENSO</span>-type oscillations had existed at the time of Cretaceous greenhouse conditions. Cored Cretaceous lacustrine sediments from the Songliao Basin in Northeast China (SK-1 cores from the International Continental Drilling Program) potentially offer a partially varved record of Cretaceous paleoclimate. Fourteen polished thin sections from the depth interval 1096.12-1096.53 m with an age of 84.4 Ma were analyzed by optical and scanning electron microscopy (SEM). ImageJ software was applied to extract gray scale curves from optical images at pixel resolution. We tracked minimum values of the gray scale curves to estimate the thickness of each lamina. Five sedimentary structures were recognized: flaser bedding, wavy bedding, lenticular bedding, horizontal bedding, and massive layers. The mean layer thicknesses with different sedimentary structures range from 116 to 162mm, very close to the mean sedimentation rate estimated for this sampled interval, 135mm/year, indicating that the layers bounded by pure clay lamina with the minimum gray values are varves. SEM images indicate that a varve is composed, in succession, of one lamina rich in coarse silt, one lamina rich in fine silt, one clay-rich lamina with some silt, and one clay-rich lamina. This suggests that a Cretaceous year featured four distinct depositional seasons, two of which were rainy and the others were lacking precipitation. Spectral analysis of extended intervals of the tuned gray scale curve indicates the presence of inter-annual periodicities of 2.2-2.7 yr, 3.5-6.1 year, and 10.1-14.5 year consistent with those of modern <span class="hlt">ENSO</span> cycles and solar cycles, as well as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.8072V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.8072V"><span>On the unstable <span class="hlt">ENSO</span>-Western North Pacific Monsoon relation during the 20th Century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vega Martín, Inmaculada; Gallego Puyol, David; Ribera Rodriguez, Pedro; Gómez Delgado, Francisco de Paula; Peña-Ortiz, Cristina</p> <p>2017-04-01</p> <p>The concept of the Western North Pacific Summer Monsoon (WNPSM) appeared for the first time in 1987. Unlike the Indian Summer Monsoon and the East Asian summer monsoon, the WNPSM is an oceanic monsoon driven essentially by the meridional gradient of sea surface temperature. Its circulation is characterized by a northwest-southeast oriented monsoon trough with intense precipitation and low-level southwesterlies and upper-tropospheric easterlies in the region [100°-130° E, 5°-15°N]. Although this monsoon is mainly oceanic, it modulates the precipitation of densely populated areas such as the Philippines. To date, the WNPSM has been quantified by the so-called Western North Pacific Monsoon Index (WNPMI), an index based on wind anomalies over large domains of the Western Pacific. The requirement of continuous observed wind over remote oceanic areas to compute the WNPMI has limited its availability to the 1949-2014 period. In this work we have extended the index by almost 100 years by using historical observations of wind direction taken aboard ships. Our Western North Pacific Directional Index (WNPDI), is defined as the sum of the persistence of the low-level westerly winds in [5°-15°N, 100°-130°E] and easterly winds in [20°-30°N, 110°-140°E]. The new WNPDI index is highly correlated to the existent WNPMI for the concurrent period (1948-2014). (r=+0.88, p<0.01), indicating that the new approach based in the use of wind direction alone (a variable that can be considered instrumental even before the 20th Century), captures most of the monsoonal signal. Previous studies found that, during the second part of the 20th Century the WNPSM exhibited two basic characteristics: first a large interannual variability and second, a significant relation between the WNPSM and the El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) in a way in which a strong (weak) WNPSM tends to occur during the El Niño (La Niña) developing year or/and La Niña (El Niño) decaying year. The analysis of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26803506','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26803506"><span>Head CT: Image quality improvement of posterior fossa and radiation dose reduction with <span class="hlt">ASi</span>R - comparative studies of CT head examinations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guziński, Maciej; Waszczuk, Łukasz; Sąsiadek, Marek J</p> <p>2016-10-01</p> <p>To evaluate head CT protocol developed to improve visibility of the brainstem and cerebellum, lower bone-related artefacts in the posterior fossa and maintain patient radioprotection. A paired comparison of head CT performed without Adaptive Statistical Iterative Reconstruction (<span class="hlt">ASi</span>R) and a clinically indicated follow-up with 40 % <span class="hlt">ASi</span>R was acquired in one group of 55 patients. Patients were scanned in the axial mode with different scanner settings for the brain and the posterior fossa. Objective image quality analysis was performed with signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality analysis was based on brain structure visibility and evaluation of the artefacts. We achieved 19 % reduction of total DLP and significantly better image quality of posterior fossa structures. SNR for white and grey matter in the cerebellum were 34 % to 36 % higher, respectively, CNR was improved by 142 % and subjective analyses were better for images with <span class="hlt">ASi</span>R. When imaging parameters are set independently for the brain and the posterior fossa imaging, <span class="hlt">ASi</span>R has a great potential to improve CT performance: image quality of the brainstem and cerebellum is improved, and radiation dose for the brain as well as total radiation dose are reduced. •With <span class="hlt">ASi</span>R it is possible to lower radiation dose or improve image quality •Sequentional imaging allows setting scan parameters for brain and posterior-fossa independently •We improved visibility of brainstem structures and decreased radiation dose •Total radiation dose (DLP) was decreased by 19.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdAtS..35..853T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdAtS..35..853T"><span><span class="hlt">ENSO</span> Predictions in an Intermediate Coupled Model Influenced by Removing Initial Condition Errors in Sensitive Areas: A Target Observation Perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, Ling-Jiang; Gao, Chuan; Zhang, Rong-Hua</p> <p>2018-07-01</p> <p>Previous studies indicate that <span class="hlt">ENSO</span> predictions are particularly sensitive to the initial conditions in some key areas (socalled "sensitive areas"). And yet, few studies have quantified improvements in prediction skill in the context of an optimal observing system. In this study, the impact on prediction skill is explored using an intermediate coupled model in which errors in initial conditions formed to make <span class="hlt">ENSO</span> predictions are removed in certain areas. Based on ideal observing system simulation experiments, the importance of various observational networks on improvement of El Niño prediction skill is examined. The results indicate that the initial states in the central and eastern equatorial Pacific are important to improve El Ni˜no prediction skill effectively. When removing the initial condition errors in the central equatorial Pacific, <span class="hlt">ENSO</span> prediction errors can be reduced by 25%. Furthermore, combinations of various subregions are considered to demonstrate the efficiency on <span class="hlt">ENSO</span> prediction skill. Particularly, seasonally varying observational networks are suggested to improve the prediction skill more effectively. For example, in addition to observing in the central equatorial Pacific and its north throughout the year, increasing observations in the eastern equatorial Pacific during April to October is crucially important, which can improve the prediction accuracy by 62%. These results also demonstrate the effectiveness of the conditional nonlinear optimal perturbation approach on detecting sensitive areas for target observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....12986S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....12986S"><span>Aspects of extratropical synoptic-scale processes in opposing <span class="hlt">ENSO</span> phases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwierz, C.; Wernli, H.; Hess, D.</p> <p>2003-04-01</p> <p>Energy and momentum provided by anomalous tropical heating/cooling affect the circulation on the global scale. Pacific Sea surface temperature anomalies strongly force local conditions in the equatorial Pacific, but are also known to change the climate in the extratropics, particularly over the American continent. The impact on more remote areas such as the Atlantic-European region is less clear. There the observed effects in both analyses and model studies show dependence on the resolution of the model/data, as well as on the time scales under consideration (Merkel and Latif, 2002; Compo et al., 2001). Most of the previous studies focus on larger-scale processes and seasonal time scales (or longer). Here we concentrate on the impact of opposing <span class="hlt">ENSO</span> phases on extratropical synoptic-scale dynamics. The investigation is undertaken for the Niño/Niña events of 1972/3 and 1973/4 respectively, for 5 winter months (NDJFM) using ECMWF ERA40 data with 1o× 1o horizontal resolution and 60 vertical levels. The examination of the resulting differences in terms of standard dynamical fields (temperature, sea level pressure, precipitation, geopotential) is complemented with additional diagnostic fields (e.g. potential vorticity (PV), anti-/cyclone tracks and frequencies, PV streamers/cut-offs, blocking) in an attempt to gain more insight into aspects of extratropical synoptic-scale dynamical processes associated with <span class="hlt">ENSO</span> SST anomalies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025104','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025104"><span>Effects of <span class="hlt">ENSO</span> on weather-type frequencies and properties at New Orleans, Louisiana, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McCabe, G.J.; Muller, R.A.</p> <p>2002-01-01</p> <p>Examination of historical climate records indicates a significant relation between the El Nin??o/Southern Oscillation (<span class="hlt">ENSO</span>) and seasonal temperature and precipitation in Louisiana. In this study, a 40 yr record of twice daily (06:00 and 15:00 h local time) weather types are used to study the effects of <span class="hlt">ENSO</span> variability on the local climate at New Orleans, Louisiana. Tropical Pacific sea-surface temperatures (SSTs) for the NINO3.4 region are used to define <span class="hlt">ENSO</span> events (i.e. El Nin??o and La Nin??a events), and daily precipitation and temperature data for New Orleans are used to define weather-type precipitation and temperature properties. Data for winters (December through February) 1962-2000 are analyzed. The 39 winters are divided into 3 categories; winters with NINO3.4 SST anomalies 1??C (El Nin??o events), and neutral conditions (all other years). For each category, weather-type frequencies and properties (i.e. precipitation and temperature) are determined and analyzed. Results indicate that El Nin??o events primarily affect precipitation characteristics of weather types at New Orleans, whereas the effects of La Nin??a events are most apparent in weather-type frequencies. During El Nin??o events, precipitation for some of the weather types is greater than during neutral and La Nin??a conditions and is related to increased water vapor transport from the Tropics to the Gulf of Mexico. The changes in weather-type frequencies during La Nin??a events are indicative of a northward shift in storm tracks and/or a decrease in storm frequency in southern Louisiana.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E2163R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E2163R"><span>A study of Solar-<span class="hlt">Enso</span> correlation with southern Brazil tree ring index (1955- 1991)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rigozo, N.; Nordemann, D.; Vieira, L.; Echer, E.</p> <p></p> <p>The effects of solar activity and El Niño-Southern Oscillation on tree growth in Southern Brazil were studied by correlation analysis. Trees for this study were native Araucaria (Araucaria Angustifolia)from four locations in Rio Grande do Sul State, in Southern Brazil: Canela (29o18`S, 50o51`W, 790 m asl), Nova Petropolis (29o2`S, 51o10`W, 579 m asl), Sao Francisco de Paula (29o25`S, 50o24`W, 930 m asl) and Sao Martinho da Serra (29o30`S, 53o53`W, 484 m asl). From these four sites, an average tree ring Index for this region was derived, for the period 1955-1991. Linear correlations were made on annual and 10 year running averages of this tree ring Index, of sunspot number Rz and SOI. For annual averages, the correlation coefficients were low, and the multiple regression between tree ring and SOI and Rz indicates that 20% of the variance in tree rings was explained by solar activity and <span class="hlt">ENSO</span> variability. However, when the 10 year running averages correlations were made, the coefficient correlations were much higher. A clear anticorrelation is observed between SOI and Index (r=-0.81) whereas Rz and Index show a positive correlation (r=0.67). The multiple regression of 10 year running averages indicates that 76% of the variance in tree ring INdex was explained by solar activity and <span class="hlt">ENSO</span>. These results indicate that the effects of solar activity and <span class="hlt">ENSO</span> on tree rings are better seen on long timescales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ClDy...48.2135F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ClDy...48.2135F"><span>Asymmetry of the winter extra-tropical teleconnections in the Northern Hemisphere associated with two types of <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, Juan; Chen, Wen; Li, Yanjie</p> <p>2017-04-01</p> <p>Asymmetric atmospheric responses to <span class="hlt">ENSO</span> are revisited after dividing it into two types: eastern-Pacific (EP) and central-Pacific (CP) <span class="hlt">ENSO</span>. The EP <span class="hlt">ENSO</span> triggers two obvious asymmetric atmospheric teleconnections: One is the Pacific-North American-like teleconnection. Its asymmetry is characterized by weaker amplitudes during the EP La Niña than EP El Niño, which is caused by a much weaker EP La Niña tropical forcing and the resultant weaker extra-tropical vorticity forcing. The other is the Atlantic-Eurasian teleconnection with negative height anomalies in the subtropical Atlantic and Eurasia and positive anomalies in the high-latitude Atlantic and northeast Asia, which appears during the EP La Niña but not during the EP El Niño. The background state plays a vital role in this asymmetry. The EP La Niña-type basic state is more conducive to propagation of the wave rays into the Atlantic-Eurasian region compared to EP El Niño situation. In contrast, the CP <span class="hlt">ENSO</span> yields an Arctic Oscillation-like teleconnection, presenting an appreciable asymmetry in the subtropical amplitudes that are stronger during the CP El Niño than during the CP La Niña. In this case, the distinct effects of the different background state on the equatorward wave rays are responsible for this asymmetry. Under the CP El Niño-type background state, the equatorward wave rays tend to be reflected at the latitudes where the zonal wind equals zero (U = 0), and then successfully captured by the subtropical westerly jet. However, under the CP La Niña-type background state, the equatorward wave rays disappear at U = 0 latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H51I1393S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H51I1393S"><span>Analysis of the Effects of <span class="hlt">ENSO</span> and Atmospheric Rivers on Precipitation in Los Angeles County</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santacruz, A.; Lamb, K.</p> <p>2017-12-01</p> <p>The Winter 2016-2017 season in California was marked by substantial amounts of precipitation; this resulted in critically-low reservoirs filling up and the removal of most of California from drought status. The year prior was characterized by one of the strongest El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) events, though it did not produce nearly enough precipitation as the 2016-2017 season. The major contributors to the increased rainfall during the 2016-2017 season were climactic phenomenon known as atmospheric rivers (ARs), which transport water vapor through the atmosphere in narrow bands, and are known to produce extreme rain events. Determining the exact timing, landfall areas, and total precipitation amounts of ARs is currently of great interest; a recent study showed that extreme weather events are likely to increase in California in the coming years, which motivates research into how phenomenon such as <span class="hlt">ENSO</span> and ARs play a role. Using long-term daily rain gauge data provided by the Los Angeles County Department of Public Works, we compute the precipitation volume and storm count for various locations in Los Angeles County and identify anomalies. These data will then be compared with the occurrence and intensity of AR and <span class="hlt">ENSO</span> events by using NOAA's NOI and ESRL AR data. The results can be used to provide a better grasp of extreme climactic patterns and their effects on the amount of precipitation in the region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3560Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3560Y"><span><span class="hlt">ENSO</span> influence on the Asian summer monsoon anticyclone as derived from the satellite observations, reanalysis and model simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Xiaolu; Konopka, Paul; Ploeger, Felix; Tao, Mengchu; Bian, Jianchun; Mueller, Rolf</p> <p>2017-04-01</p> <p>El Nino and La Nina are opposite phases of El Nino-Southern Oscillation (<span class="hlt">ENSO</span>). The extremes of <span class="hlt">ENSO</span> patterns have impacts not only on ocean processes, but also on global weather and climate. The <span class="hlt">ENSO</span> activities typically show pronounced features in boreal winter time, but some prolonged events may last for months or years. In this study we analyze the influence of <span class="hlt">ENSO</span> on the atmospheric composition in the tropical and extra-tropical UTLS region in the months following strong <span class="hlt">ENSO</span> events. In particular, we are interested in the impact of <span class="hlt">ENSO</span> on the Asian summer monsoon (ASM) anticyclone. Using the Multivariate <span class="hlt">ENSO</span> Index (MEI), we define two composites starting from strong El Nino and La Nina winters (|MEI|>0.9) and analyze the anomalies caused by them in the following months. To quantify the differences in dynamics, the velocity potential (VP) and the stream function (SF) are calculated based on ERA-Interim reanalysis from 1979 to 2015. SF shows that during winter the horizontal flow in the tropical UTLS is dominated by two equatorially symmetric anticyclones resembling the well-known Matsuno-Gill solution. In summer, the anticyclone in the North Hemisphere is shifted to the ASM region. VP shows that the centers of the divergent part of the flow lie in the West Tropical Pacific and Central Pacific for La Nina and El Nino winters, respectively. These centers move northwestwards during spring and summer. The anticyclone, subtropical jet and the divergent part of the flow after La Nina winters are significantly stronger than after El Nino winters. Based on the MLS measurements of CO, H2O and O3 from 2004 to 2015, we also discuss the respective anomalies at the tropopause level for the El Nino/La Nina composites. EL Nino composite of CO shows higher values in the tropical region not only during winter but also during spring and summer. La Nina composite of H2O shows low anomaly over Maritime Continent which spread over the whole tropics until summer. The H2O</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6717P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6717P"><span>Changes in El Nino - Southern Oscillation (<span class="hlt">ENSO</span>) conditions during the Younger Dryas revealed by New Zealand tree-rings.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palmer, Jonathan; Turney, Chris; Cook, Edward; Fenwick, Pavla; Thomas, Zoë; Helle, Gerhard; Jones, Richard; Clement, Amy; Hogg, Alan; Southon, John; Bronk Ramsey, Christopher; Staff, Richard; Muscheler, Raimund; Corrège, Thierry; Hua, Quan</p> <p>2017-04-01</p> <p>The warming trend at the end of the last glacial was disrupted by rapid cooling clearly identified in Greenland (Greenland Stadial 1 or GS-1) and Europe (Younger Dryas Stadial or YD). This reversal to glacial-like conditions is one of the best known examples of abrupt change but the exact timing and global spatial extent remains uncertain. Whilst the wider Atlantic region has a network of high-resolution proxy records spanning the YD, the Pacific Ocean suffers from a scarcity of sub-decadally resolved sequences. Here we report the results from an investigation into a tree-ring chronology from northern New Zealand aimed at addressing the paucity of data. The conifer tree species kauri (Agathis australis) is known from contemporary studies to be sensitive to regional climate changes. An analysis of a 'historic' 452-year kauri chronology confirms a tropical-Pacific teleconnection via the El Niño - Southern Oscillation (<span class="hlt">ENSO</span>). We then focus our study to a 1010-year subfossil kauri chronology that has been precisely dated by comprehensive radiocarbon dating and contains a striking ring-width downturn between 12,500 to 12,380 cal BP within the YD. Wavelet analysis shows a marked increase in <span class="hlt">ENSO</span>-like periodicities occurring after the downturn event. Comparison to low- and mid-latitude Pacific records suggests a coherency in the changes to <span class="hlt">ENSO</span> and Southern Hemisphere westerly airflow during this period. The drivers for this climate event remain unclear but may be related to solar changes that subsequently led to establishment and/or increased expression of <span class="hlt">ENSO</span> across the mid-latitudes of the Pacific, seemingly independent of the Atlantic and polar regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26922785','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26922785"><span>ASSESSMENT OF CLINICAL IMAGE QUALITY IN PAEDIATRIC ABDOMINAL CT EXAMINATIONS: DEPENDENCY ON THE LEVEL OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION (<span class="hlt">ASi</span>R) AND THE TYPE OF CONVOLUTION KERNEL.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Larsson, Joel; Båth, Magnus; Ledenius, Kerstin; Caisander, Håkan; Thilander-Klang, Anne</p> <p>2016-06-01</p> <p>The purpose of this study was to investigate the effect of different combinations of convolution kernel and the level of Adaptive Statistical iterative Reconstruction (<span class="hlt">ASi</span>R™) on diagnostic image quality as well as visualisation of anatomical structures in paediatric abdominal computed tomography (CT) examinations. Thirty-five paediatric patients with abdominal pain with non-specified pathology undergoing abdominal CT were included in the study. Transaxial stacks of 5-mm-thick images were retrospectively reconstructed at various <span class="hlt">ASi</span>R levels, in combination with three convolution kernels. Four paediatric radiologists rated the diagnostic image quality and the delineation of six anatomical structures in a blinded randomised visual grading study. Image quality at a given <span class="hlt">ASi</span>R level was found to be dependent on the kernel, and a more edge-enhancing kernel benefitted from a higher <span class="hlt">ASi</span>R level. An <span class="hlt">ASi</span>R level of 70 % together with the Soft™ or Standard™ kernel was suggested to be the optimal combination for paediatric abdominal CT examinations. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24086670','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24086670"><span>A structural equation model analysis of relationships among <span class="hlt">ENSO</span>, seasonal descriptors and wildfires.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Slocum, Matthew G; Orzell, Steve L</p> <p>2013-01-01</p> <p>Seasonality drives ecological processes through networks of forcings, and the resultant complexity requires creative approaches for modeling to be successful. Recently ecologists and climatologists have developed sophisticated methods for fully describing seasons. However, to date the relationships among the variables produced by these methods have not been analyzed as networks, but rather with simple univariate statistics. In this manuscript we used structural equation modeling (SEM) to analyze a proposed causal network describing seasonality of rainfall for a site in south-central Florida. We also described how this network was influenced by the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), and how the network in turn affected the site's wildfire regime. Our models indicated that wet and dry seasons starting later in the year (or ending earlier) were shorter and had less rainfall. El Niño conditions increased dry season rainfall, and via this effect decreased the consistency of that season's drying trend. El Niño conditions also negatively influenced how consistent the moistening trend was during the wet season, but in this case the effect was direct and did not route through rainfall. In modeling wildfires, our models showed that area burned was indirectly influenced by <span class="hlt">ENSO</span> via its effect on dry season rainfall. Area burned was also indirectly reduced when the wet season had consistent rainfall, as such wet seasons allowed fewer wildfires in subsequent fire seasons. Overall area burned at the study site was estimated with high accuracy (R (2) score = 0.63). In summary, we found that by using SEMs, we were able to clearly describe causal patterns involving seasonal climate, <span class="hlt">ENSO</span> and wildfire. We propose that similar approaches could be effectively applied to other sites where seasonality exerts strong and complex forcings on ecological processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23894926','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23894926"><span>Massive bleaching of coral reefs induced by the 2010 <span class="hlt">ENSO</span>, Puerto Cabello, Venezuela.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>del Mónaco, Carlos; Haiek, Gerard; Narciso, Samuel; Galindo, Miguel</p> <p>2012-06-01</p> <p>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) has generated global coral massive bleaching. The aim of this work was to evaluate the massive bleaching of coral reefs in Puerto Cabello, Venezuela derived from <span class="hlt">ENSO</span> 2010. We evaluated the bleaching of reefs at five localities both at three and five meter depth. The coral cover and densities of colonies were estimated. We recorded living coral cover, number and diameter of bleached and non-bleached colonies of each coral species. The colonies were classified according to the proportion of bleached area. Satellite images (Modis Scar) were analyzed for chlorophyll-a concentration and temperature in August, September, October and November from 2008-2010. Precipitation, wind speed and air temperature information was evaluated in meteorological data for 2009 and 2010. A total of 58.3% of colonies, belonging to 11 hexacoral species, were affected and the greatest responses were observed in Colpophyllia natans, Montastraea annularis and Montastraeafaveolata. The most affected localities were closer to the mainland and had a bleached proportion up to 62.73+/-36.55%, with the highest proportion of affected colonies, whereas the farthest locality showed 20.25+/-14.00% bleached and the smallest proportion. The salinity in situ varied between 30 and 33ppm and high levels of turbidity were observed. According to the satellite images, in 2010 the surface water temperature reached 31 degree C in August, September and October, and resulted higher than those registered in 2008 and 2009. Regionally, chlorophyll values were higher in 2010 than in 2008 and 2009. The meteorological data indicated that precipitation in November 2010 was three times higher than in November 2009. Massive coral bleaching occurred due to a three month period of high temperatures followed by one month of intense <span class="hlt">ENSO</span>-associated precipitation. However, this latter factor was likely the trigger because of the bleaching gradient observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3782436','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3782436"><span>A Structural Equation Model Analysis of Relationships among <span class="hlt">ENSO</span>, Seasonal Descriptors and Wildfires</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Slocum, Matthew G.; Orzell, Steve L.</p> <p>2013-01-01</p> <p>Seasonality drives ecological processes through networks of forcings, and the resultant complexity requires creative approaches for modeling to be successful. Recently ecologists and climatologists have developed sophisticated methods for fully describing seasons. However, to date the relationships among the variables produced by these methods have not been analyzed as networks, but rather with simple univariate statistics. In this manuscript we used structural equation modeling (SEM) to analyze a proposed causal network describing seasonality of rainfall for a site in south-central Florida. We also described how this network was influenced by the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), and how the network in turn affected the site’s wildfire regime. Our models indicated that wet and dry seasons starting later in the year (or ending earlier) were shorter and had less rainfall. El Niño conditions increased dry season rainfall, and via this effect decreased the consistency of that season’s drying trend. El Niño conditions also negatively influenced how consistent the moistening trend was during the wet season, but in this case the effect was direct and did not route through rainfall. In modeling wildfires, our models showed that area burned was indirectly influenced by <span class="hlt">ENSO</span> via its effect on dry season rainfall. Area burned was also indirectly reduced when the wet season had consistent rainfall, as such wet seasons allowed fewer wildfires in subsequent fire seasons. Overall area burned at the study site was estimated with high accuracy (R 2 score = 0.63). In summary, we found that by using SEMs, we were able to clearly describe causal patterns involving seasonal climate, <span class="hlt">ENSO</span> and wildfire. We propose that similar approaches could be effectively applied to other sites where seasonality exerts strong and complex forcings on ecological processes. PMID:24086670</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.475...25C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.475...25C"><span><span class="hlt">ENSO</span> variability reflected in precipitation oxygen isotopes across the Asian Summer Monsoon region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Zhongyin; Tian, Lide; Bowen, Gabriel J.</p> <p>2017-10-01</p> <p>Oxygen isotope signals (δ18O) from paleo-archives are important proxies for past Asian Summer Monsoon (ASM) climate reconstruction. However, causes of interannual variation in the δ18O values of modern precipitation across the ASM region remain in argument. We report interannual δ18O variation in southern Tibetan Plateau precipitation based on long-term observations at Lhasa. These data, together with precipitation δ18O records from five Global Network of Isotopes in Precipitation (GNIP) stations and two ice core δ18O records, were used to define a regional metric of ASM precipitation δ18O (ASMOI). Back-trajectory analyses for rainy season precipitation events indicate that moisture sources vary little between years with relatively high and low δ18O values, a result that is consistent for the south (Lhasa), southeast (Bangkok), and east ASM regions (Hong Kong). In contrast, δ18O values at these three locations are significantly correlated with convection in the estimated source regions and along transport paths. These results suggest that upstream convection, rather than moisture source change, causes interannual variation in ASM precipitation δ18O values. Contrasting values of the ASMOI in El Niño and La Niña years reveal a positive isotope-El Niño Southern Oscillation (<span class="hlt">ENSO</span>) response (e.g., high values corresponding to warm phases), which we interpret as a response to changes in regional convection. We show that the isotope-<span class="hlt">ENSO</span> response is amplified at high elevation sites and during La Niña years. These findings should improve interpretations of paleo-δ18O data as a proxy for past ASM variation and provide new opportunities to use data from this region to study paleo-<span class="hlt">ENSO</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GeoRL..30.1006R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GeoRL..30.1006R"><span><span class="hlt">ENSO</span> related variability in the Southern Hemisphere, 1948-2000</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ribera, Pedro; Mann, Michael E.</p> <p>2003-01-01</p> <p>The spatiotemporal evolution of Southern Hemisphere climate variability is diagnosed based on the use of the NCEP reanalysis (1948-2000) dataset. Using the MTM-SVD analysis method, significant narrowband variability is isolated from the multi-variate dataset. It is found that the <span class="hlt">ENSO</span> signal exhibits statistically significant behavior at quasiquadrennial (3-6 yr) timescales for the full time-period. A significant quasibiennial (2-3 yr) timescales emerges only for the latter half of period. Analyses of the spatial evolution of the two reconstructed signals shed additional light on linkages between low and high-latitude Southern Hemisphere climate anomalies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhLA..236..577V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhLA..236..577V"><span>The energy gap in <span class="hlt">a-Si</span> 1 - xC g: H alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valladares, Ariel A.; Valladares, Alexander; Enrique Sansores, L.; Nelis, Mary Ann Me</p> <p>1997-02-01</p> <p>The electronic structure of amorphous tetrahedral clusters of the type <span class="hlt">a-Si</span> 1 - xC g: H are studied using the pseudopotential SCF Hartree-Fock approximation. The reduced energy gap isgiven by Egr( x) - 1 + 0.84 x for x ⩽ 0.5, whereas experimentally Egr( x) = 1 + 0.96 x. For x ⩾ 0.5 the dip in the gap value reported experimentally is verified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16690051','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16690051"><span>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and dysentery in Shandong province, China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Ying; Bi, Peng; Wang, Guoyong; Hiller, Janet E</p> <p>2007-01-01</p> <p>To investigate the impact of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) on dysentery transmission, the relationship between monthly dysentery cases in Shandong Province of China and the monthly Southern Oscillation Index (SOI), a broad index of <span class="hlt">ENSO</span>, was examined over the period 1991-2003. Spearman correlations and generalized linear models were calculated to detect the association between the SOI and dysentery cases. Data from 1991 to 2001 were used to estimate the parameters, while data from 2002 to 2003 were used to test the forecasting ability of the model. After controlling for seasonality, autocorrelation, and a time-lagged effect, the results indicate that there was a significant negative association between the number of dysentery cases and the SOI, with a lagged effect of 2 months. A one-standard-deviation decrease in the SOI might cause up to 207 more dysentery cases per month in Shandong Province. This is the first report of the impact of the Southern Oscillation on dysentery risk in China, indicating that the SOI may be a useful early indicator of potential dysentery risk in Shandong Province.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996PhDT.........7X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996PhDT.........7X"><span>Predictability of a Coupled Model of <span class="hlt">ENSO</span> Using Singular Vector Analysis: Optimal Growth and Forecast Skill.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xue, Yan</p> <p></p> <p>The optimal growth and its relationship with the forecast skill of the Zebiak and Cane model are studied using a simple statistical model best fit to the original nonlinear model and local linear tangent models about idealized climatic states (the mean background and <span class="hlt">ENSO</span> cycles in a long model run), and the actual forecast states, including two sets of runs using two different initialization procedures. The seasonally varying Markov model best fit to a suite of 3-year forecasts in a reduced EOF space (18 EOFs) fits the original nonlinear model reasonably well and has comparable or better forecast skill. The initial error growth in a linear evolution operator A is governed by the eigenvalues of A^{T}A, and the square roots of eigenvalues and eigenvectors of A^{T}A are named singular values and singular vectors. One dominant growing singular vector is found, and the optimal 6 month growth rate is largest for a (boreal) spring start and smallest for a fall start. Most of the variation in the optimal growth rate of the two forecasts is seasonal, attributable to the seasonal variations in the mean background, except that in the cold events it is substantially suppressed. It is found that the mean background (zero anomaly) is the most unstable state, and the "forecast IC states" are more unstable than the "coupled model states". One dominant growing singular vector is found, characterized by north-south and east -west dipoles, convergent winds on the equator in the eastern Pacific and a deepened thermocline in the whole equatorial belt. This singular vector is insensitive to initial time and optimization time, but its final pattern is a strong function of initial states. The <span class="hlt">ENSO</span> system is inherently unpredictable for the dominant singular vector can amplify 5-fold to 24-fold in 6 months and evolve into the large scales characteristic of <span class="hlt">ENSO</span>. However, the inherent <span class="hlt">ENSO</span> predictability is only a secondary factor, while the mismatches between the model and data is a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000090520&hterms=climate+change+climate+patterns&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dclimate%2Bchange%2Bclimate%2Bpatterns','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000090520&hterms=climate+change+climate+patterns&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dclimate%2Bchange%2Bclimate%2Bpatterns"><span>The Evolution of Tropical Precipitation Patterns During <span class="hlt">ENSO</span> Events Using 21+ Years of GPCP Merged Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, Scott; Adler, Robert</p> <p>2000-01-01</p> <p>The <span class="hlt">ENSO</span> phenomenon is characterized by fluctuations in the climate system of the tropical Pacific. Quantifying changes in the precipitation component of this system is important in understanding the distribution of heating in the atmosphere which drives the large-scale circulation and affects the weather patterns in the mid-latitudes. Monitoring precipitation anomalies in the Pacific is also an important component for tracking the evolution of <span class="hlt">ENSO</span>. The most timely and complete observations of the earth come from satellite instruments. In this study, the state of the art satellite-gauge merged monthly precipitation data set from the Global Precipitation Climatology Project (GPCP) is used to depict tropical rainfall patterns during <span class="hlt">ENSO</span> events over the past two decades and quantify these patterns using indices. This analysis will be complemented by daily precipitation data which can resolve the Madden-Julian Oscillation and westerly wind burst events. The 1997-98 El Nino and 1998-2000 La Nina were the best observed <span class="hlt">ENSO</span> cycle in the historic record. Prior to the El Nino (in terms of anomalous warming of the east Pacific) dry anomalies over the Maritime Continent were observed in February 1997 as a westerly wind burst advected convection to the east. The largest SST anomalies occurred around November-December 1997, which were followed by the largest precipitation anomalies in the beginning of 1998. The largest precipitation departures from normal were not colocated with the SST anomalies, but were further west, In the spring of 1998 negative precipitation anomalies to the north of the equator intensified, signaling the mature phase of the El Nino. A rapid increase in the precipitation-based La Nina index from December-January 1998 to March-April 1998 signaled the coming La Nina. The 1982-1983 El Nino was comparable in strength (according to several indices) and the precipitation patterns evolved in a similar fashion. For the 1998-2000 La Nina, the coldest anomalies</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21369003','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21369003"><span>GaInAsP/InP lateral-current-injection distributed feedback laser with <span class="hlt">a-Si</span> surface grating.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shindo, Takahiko; Okumura, Tadashi; Ito, Hitomi; Koguchi, Takayuki; Takahashi, Daisuke; Atsumi, Yuki; Kang, Joonhyun; Osabe, Ryo; Amemiya, Tomohiro; Nishiyama, Nobuhiko; Arai, Shigehisa</p> <p>2011-01-31</p> <p>We fabricated a novel lateral-current-injection-type distributed feedback (DFB) laser with amorphous-Si (<span class="hlt">a-Si</span>) surface grating as a step to realize membrane lasers. This laser consists of a thin GaInAsP core layer grown on a semi-insulating InP substrate and a 30-nm-thick <span class="hlt">a-Si</span> surface layer for DFB grating. Under a room-temperature continuous-wave condition, a low threshold current of 7.0 mA and high efficiency of 43% from the front facet were obtained for a 2.0-μm stripe width and 300-μm cavity length. A small-signal modulation bandwidth of 4.8 GHz was obtained at a bias current of 30 mA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMOS24C..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMOS24C..08S"><span>Long-Term <span class="hlt">ENSO</span> Variation Over the Last 20,000 Years From the Peru Continental Margin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skilbeck, G.; Fink, D.; Gagan, M.; Rein, B.</p> <p>2006-12-01</p> <p>Three ODP Leg 201 cores from the Peru continental margin comprise highly laminated diatomaceous ooze spanning Last Glacial Maximum to present. Geochemical proxy data, layer counting and spectral analysis of red color variation suggest the layers represent interannual accumulation under the influence tropical <span class="hlt">ENSO</span> conditions, with darker layers representing El Niño events. AMS 14-C dating (Skilbeck &Fink, 2006) of bulk sediment from Sites 201-1228 and -1229 (~11°S) and comparison with Rein et al. (2005) Core SO147-106KL (~12°S) show that where the shelf is narrow south of ~10.5°S, regionally consistent rates of sediment accumulation have occurred over the late Deglaciation and Holocene, with high rates characterising the late (0-2.0 kyrBP, ~100 cm/ka) and the early (8.5-10 kyrBP, ~80 cm/ka) Holocene. Over these intervals laminae are of interannual resolution. Further north where the shelf is broader, Holocene-Late Deglaciation sediments are thin or absent, but the Early Deglaciation is well represented. In a core from ODP Site 201-1227 (~9°S, 427m water depth), the period 15.5-17.5 kyrBP is characterised by sediment accumulation rates in excess of 300 cm/ka, and interannual laminations are again present. Spectral analysis of the instrumental record of <span class="hlt">ENSO</span>, the SOI, shows a relative stable mode of variation with an average frequency of about 5.5 yr for the past 130 years. Analysis of our ODP cores shows that the <span class="hlt">ENSO</span> mode appears to be relatively stable for periods of 300-500 years throughout the Holocene with frequencies varying mostly between 5 and 8 years and relatively sudden mode switches, suggesting inter alia that the instrumental record is not long enough to test predictive models of <span class="hlt">ENSO</span> variation. Throughout the Holocene, this pattern of variation transcends the sedimentation-rate zones identified above, with the inference that changes in the rate of sedimentation have not influenced the temporal pattern. The later part of the deglaciation period (10</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP11A1790X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP11A1790X"><span>Changes in Indonesian Outflow in relation to East Asian Monsoon and <span class="hlt">ENSO</span> Activities since the Last Glacial</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, J.</p> <p>2013-12-01</p> <p>The Indonesian Throughflow (ITF) links upper ocean waters of the west Pacific and Indian Ocean, modulates heat and fresh water budgets between these oceans and in turn plays an important role in global climate change. It was suggested that East Asian monsoon and El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) exert a strong influence on flux, water properties and vertical stratification of the modern ITF. Possible link of the ITF to <span class="hlt">ENSO</span> is also supported by significant linear correlation (R2=0.43) between thermocline temperature (TT) of the ITF outflow and NINO3.4 index over the past 50 years. In this work, seawater temperatures and salinity and vertical thermal structure of the ITF outflow since the last glacial were reconstructed from Core SO18462 that was retrieved from exit of the ITF to the Timor Sea (TS) (Holbourn et al., 2011). The records of Core SO18462 were then compared with records of Core 3cBX that were considered to reveal <span class="hlt">ENSO</span>-like conditions in the center of the western Pacific warm pool (WPWP) (Sagawa et al., 2012). The results show that surface waters were comparable in the TS and the WPWP prior to ~16ka, and then diverged with much freshening in the TS. On the contrary, thermocline waters were largely diverged, warmer and more saline in the TS than in the WPWP, and then started to converge from ~16ka. Sea surface temperature (SST) remained over 28°C (the temperature defining range of modern WPWP) in both of the regions during 11.5-6ka. SST then slightly decreased below 28°C in the TS when it kept all the way above 28°C in the WPWP towards the late Holocene. In contrast, TT and thermocline depth remained overall unchanged in the WPWP, concurring with decreasing of TT and shoaling of thermocline in the TS during 11.5-6ka. After 6ka, thermocline continued shoaling in the TS, when TT remained decreasing and thermocline salinity approached to be similar in both of the regions. Comparison of TS and WPWP records conspicuously disclose two categories of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4270789','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4270789"><span>El Niño Southern Oscillation (<span class="hlt">ENSO</span>) Enhances CO2 Exchange Rates in Freshwater Marsh Ecosystems in the Florida Everglades</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Malone, Sparkle L.; Staudhammer, Christina L.; Oberbauer, Steven F.; Olivas, Paulo; Ryan, Michael G.; Schedlbauer, Jessica L.; Loescher, Henry W.; Starr, Gregory</p> <p>2014-01-01</p> <p>This research examines the relationships between El Niño Southern Oscillation (<span class="hlt">ENSO</span>), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009–2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in <span class="hlt">ENSO</span> phase, suggesting that extreme <span class="hlt">ENSO</span> phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in both <span class="hlt">ENSO</span> phase and annual net CO2 exchange rates co-occurred with changes in wet and dry season length and intensity. Combined with site-specific seasonality in CO2 exchanges rates, El Niño and La Niña phases magnified season intensity and CO2 exchange rates at both sites. At TS, net CO2 uptake rates were higher in the dry season, whereas SRS had greater rates of carbon sequestration during the wet season. As La Niña phases were concurrent with drought years and extended dry seasons, TS became a greater sink for CO2 on an annual basis (−11 to −110 g CO2 m−2 yr−1) compared to El Niño and neutral years (−5 to −43.5 g CO2 m−2 yr−1). SRS was a small source for CO2 annually (1.81 to 80 g CO2 m−2 yr−1) except in one exceptionally wet year that was associated with an El Niño phase (−16 g CO2 m−2 yr−1). Considering that future climate predictions suggest a higher frequency and intensity in El Niño and La Niña phases, these results indicate that changes in extreme <span class="hlt">ENSO</span> phases will significantly alter CO2 dynamics in the Florida Everglades. PMID:25521299</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22098712-forward-bias-method-lag-correction-si-flat-panel-detector','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22098712-forward-bias-method-lag-correction-si-flat-panel-detector"><span>A forward bias method for lag correction of an <span class="hlt">a-Si</span> flat panel detector</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Starman, Jared; Tognina, Carlo; Partain, Larry</p> <p>2012-01-15</p> <p>Purpose: Digital <span class="hlt">a-Si</span> flat panel (FP) x-ray detectors can exhibit detector lag, or residual signal, of several percent that can cause ghosting in projection images or severe shading artifacts, known as the radar artifact, in cone-beam computed tomography (CBCT) reconstructions. A major contributor to detector lag is believed to be defect states, or traps, in the <span class="hlt">a-Si</span> layer of the FP. Software methods to characterize and correct for the detector lag exist, but they may make assumptions such as system linearity and time invariance, which may not be true. The purpose of this work is to investigate a new hardwaremore » based method to reduce lag in an <span class="hlt">a-Si</span> FP and to evaluate its effectiveness at removing shading artifacts in CBCT reconstructions. The feasibility of a novel, partially hardware based solution is also examined. Methods: The proposed hardware solution for lag reduction requires only a minor change to the FP. For pulsed irradiation, the proposed method inserts a new operation step between the readout and data collection stages. During this new stage the photodiode is operated in a forward bias mode, which fills the defect states with charge. A Varian 4030CB panel was modified to allow for operation in the forward bias mode. The contrast of residual lag ghosts was measured for lag frames 2 and 100 after irradiation ceased for standard and forward bias modes. Detector step response, lag, SNR, modulation transfer function (MTF), and detective quantum efficiency (DQE) measurements were made with standard and forward bias firmware. CBCT data of pelvic and head phantoms were also collected. Results: Overall, the 2nd and 100th detector lag frame residual signals were reduced 70%-88% using the new method. SNR, MTF, and DQE measurements show a small decrease in collected signal and a small increase in noise. The forward bias hardware successfully reduced the radar artifact in the CBCT reconstruction of the pelvic and head phantoms by 48%-81%. Conclusions: Overall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AMT....11.1333W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AMT....11.1333W"><span>Atmospheric QBO and <span class="hlt">ENSO</span> indices with high vertical resolution from GNSS radio occultation temperature measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilhelmsen, Hallgeir; Ladstädter, Florian; Scherllin-Pirscher, Barbara; Steiner, Andrea K.</p> <p>2018-03-01</p> <p>We provide atmospheric temperature variability indices for the tropical troposphere and stratosphere based on global navigation satellite system (GNSS) radio occultation (RO) temperature measurements. By exploiting the high vertical resolution and the uniform distribution of the GNSS RO temperature soundings we introduce two approaches, both based on an empirical orthogonal function (EOF) analysis. The first method utilizes the whole vertical and horizontal RO temperature field from 30° S to 30° N and from 2 to 35 km altitude. The resulting indices, the leading principal components, resemble the well-known patterns of the Quasi-Biennial Oscillation (QBO) and the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) in the tropics. They provide some information on the vertical structure; however, they are not vertically resolved. The second method applies the EOF analysis on each altitude level separately and the resulting indices contain information on the horizontal variability at each densely available altitude level. They capture more variability than the indices from the first method and present a mixture of all variability modes contributing at the respective altitude level, including the QBO and <span class="hlt">ENSO</span>. Compared to commonly used variability indices from QBO winds or <span class="hlt">ENSO</span> sea surface temperature, these new indices cover the vertical details of the atmospheric variability. Using them as proxies for temperature variability is also of advantage because there is no further need to account for response time lags. Atmospheric variability indices as novel products from RO are expected to be of great benefit for studies on atmospheric dynamics and variability, for climate trend analysis, as well as for climate model evaluation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmRe.198...56K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmRe.198...56K"><span>Variability modes of precipitation along a Central Mediterranean area and their relations with <span class="hlt">ENSO</span>, NAO, and other climatic patterns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalimeris, Anastasios; Ranieri, Ezio; Founda, Dimitra; Norrant, Caroline</p> <p>2017-12-01</p> <p>This study analyses a century-long set of precipitation time series in the Central Mediterranean (encompassing the Greek Ionian and the Italian Puglia regions) and investigates the statistically significant modes of the interannual precipitation variability using efficient methods of spectral decomposition. The statistical relations and the possible physical couplings between the detected modes and the global or hemispheric patterns of climatic variability (the El Niño Southern Oscillation or <span class="hlt">ENSO</span>, the North Atlantic Oscillation or NAO, the East Atlantic or EA, the Scandinavian or SCAND, and others) were examined in the time-frequency domain and low-order synchronization events were sought. Significant modes of precipitation variability were detected in the Taranto Gulf and the southern part of the Greek Ionian region at the sub-decadal scales (mostly driven by the SCAND pattern) and particularly at the decadal and quasi-decadal scales, where strong relations found with the <span class="hlt">ENSO</span> activity (under complex implications of EA and NAO) prior to the 1930s or after the early-1970s. The precipitation variations in the Adriatic stations of Puglia are dominated by significant bi-decadal modes which found to be coherent with the <span class="hlt">ENSO</span> activity and also weakly related with the Atlantic Ocean sea surface temperature intrinsic variability. Additionally, important discontinuities characterize the evolution of precipitation in certain stations of the Taranto Gulf and the Greek Ionian region during the early-1960s and particularly during the early-1970s, followed by significant reductions in the mean annual precipitation. These discontinuities seem to be associated with regional effects of NAO and SCAND, probably combined with the impact of the 1970s climatic shift in the Pacific and the <span class="hlt">ENSO</span> variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5467L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5467L"><span>Characterization of extreme flood and drought events in Singapore and investigation of their relationships with <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xin; Babovic, Vladan</p> <p>2016-04-01</p> <p>Flood and drought are hydrologic extreme events that have significant impact on human and natural systems. Characterization of flood and drought in terms of their start, duration and strength, and investigation of the impact of natural climate variability (i.e., <span class="hlt">ENSO</span>) and anthropogenic climate change on them can help decision makers to facilitate adaptions to mitigate potential enormous economic costs. To date, numerous studies in this area have been conducted, however, they are primarily focused on extra-tropical regions. Therefore, this study presented a detailed framework to characterize flood and drought events in a tropical urban city-state (i.e., Singapore), based on daily data from 26 precipitation stations. Flood and drought events are extracted from standardized precipitation anomalies from monthly to seasonal time scales. Frequency, duration and magnitude of flood and drought at all the stations are analyzed based on crossing theory. In addition, spatial variation of flood and drought characteristics in Singapore is investigated using ordinary kriging method. Lastly, the impact of <span class="hlt">ENSO</span> condition on flood and drought characteristics is analyzed using regional regression method. The results show that Singapore can be prone to extreme flood and drought events at both monthly and seasonal time scales. <span class="hlt">ENSO</span> has significant influence on flood and drought characteristics in Singapore, but mainly during the South West Monsoon season. During the El Niño phase, drought can become more extreme. The results have implications for water management practices in Singapore.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70098178','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70098178"><span>Rocky Mountain hydroclimate: Holocene variability and the role of insolation, <span class="hlt">ENSO</span>, and the North American Monsoon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anderson, Lesleigh</p> <p>2012-01-01</p> <p>Over the period of instrumental records, precipitation maximum in the headwaters of the Colorado Rocky Mountains has been dominated by winter snow, with a substantial degree of interannual variability linked to Pacific ocean–atmosphere dynamics. High-elevation snowpack is an important water storage that is carefully observed in order to meet increasing water demands in the greater semi-arid region. The purpose here is to consider Rocky Mountain water trends during the Holocene when known changes in earth's energy balance were caused by precession-driven insolation variability. Changes in solar insolation are thought to have influenced the variability and intensity of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>), Pacific Decadal Oscillation (PDO), and North American Monsoon and the seasonal precipitation balance between rain and snow at upper elevations. Holocene records are presented from two high elevation lakes located in northwest Colorado that document decade-to-century scale precipitation seasonality for the past ~ 7000 years. Comparisons with sub-tropical records of <span class="hlt">ENSO</span> indicate that the snowfall-dominated precipitation maxima developed ~ 3000 and 4000 years ago, coincident with evidence for enhanced <span class="hlt">ENSO</span>/PDO dynamics. During the early-to-mid Holocene the records suggest a more monsoon affected precipitation regime with reduced snowpack, more rainfall, and net moisture deficits that were more severe than recent droughts. The Holocene perspective of precipitation indicates a far broader range of variability than that of the past century and highlights the non-linear character of hydroclimate in the U.S. west.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/2437','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/2437"><span>Statewide Intelligent Transportation Systems <span class="hlt">As-Is</span> Agency Reports For Minnesota, Volume 1: Mn/DOT Metropolitan Division</span></a></p> <p><a target="_blank" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>1996-08-01</p> <p>THIS DOCUMENT, STATEWIDE ITS <span class="hlt">AS-IS</span> AGENCY REPORTS FOR MINNESOTA, CONSISTS OF A COLLECTION OF INDIVIDUAL SYSTEM SURVEY REPORTS RELATED TO TRANSPORTATION SYSTEMS. THE POLARIS PROJECT WILL USE THE SURVEY INFORMATION COLLECTED TO DERIVE THE EXISTING ARCH...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PEPS....4....5B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PEPS....4....5B"><span>A 2700-year record of <span class="hlt">ENSO</span> and PDO variability from the Californian margin based on coccolithophore assemblages and calcification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaufort, Luc; Grelaud, Michaël</p> <p>2017-12-01</p> <p>The El Niño Southern Oscillation (<span class="hlt">ENSO</span>) and the Pacific Decadal Oscillation (PDO) account for a large part of modern climate variability. Over the last decades, understanding of these modes of climate variability has increased but prediction in the context of global warming has proven difficult because of the lack of pertinent and reproducible paleodata. Here, we infer the dynamics of these oscillations from fossil assemblage and calcification state of coccolithophore in the Californian margin because El Niño has a strong impact on phytoplankton ecology and PDO on the upwelling intensity and hence on the ocean chemistry. Intense Californian upwelling brings water rich in CO2 and poor in carbonate ions and coccolithophores secrete lower calcified coccoliths. Seasonally laminated sediments of the Santa Barbara Basin are used to document <span class="hlt">ENSO</span> variability and PDO index for the last 2700 years at a temporal resolution of 3 years. The records present the same characteristics as other PDO or <span class="hlt">ENSO</span> records from the same area spanning the last centuries. We are therefore confident on the value produced here for the last 2.7 millennia. The records show important centennial variability that is equivalent to solar cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1916140S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1916140S"><span>The impact of the 2015-2016 El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) event on greenhouse gas exchange and surface energy budget in an Indonesian oil palm plantation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stiegler, Christian; Meijide, Ana; June, Tania; Knohl, Alexander</p> <p>2017-04-01</p> <p>The 2015-2016 El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) event was one of the strongest observed in the last 20 years. Oil palm plantations cover a large fraction of tropical lowlands in Southeast Asia but despite their growing areal extent, measurements and observations of greenhouse gas exchange and surface energy balance are still scarce. In addition, the effects of extreme events such as <span class="hlt">ENSO</span> on carbon sequestration and the partitioning of surface energy balance components are widely unknown. In this study, we use micrometeorological measurements located in commercial oil palm plantations in the Jambi province (Sumatra, Indonesia) to assess the impact of the 2015-2016 <span class="hlt">ENSO</span> event and severe forest fires on greenhouse gas exchange and surface energy budget. Continuous measurements are in operation since July 2013 and we assess turbulent fluxes of carbon dioxide (CO2), water vapour and sensible heat using the eddy covariance technique before, during and after the 2015-2016 <span class="hlt">ENSO</span> event. In the beginning of the <span class="hlt">ENSO</span> event, the area experienced a strong drought with decreasing soil moisture, increasing air and surface temperatures, and strong atmospheric vapour pressure deficit. During the peak of the drought from August to October 2015, hundreds of forest fires in the area resulted in strong smoke production, decreasing incoming solar radiation by 35% compared to pre-<span class="hlt">ENSO</span> values and diffuse radiation became almost the sole shortwave radiation flux. During the beginning of the drought, carbon uptake of the oil palm plantation was around 2.1 gC m-2 d-1 and initially increased by 50% due to clear-sky conditions and high incoming photosynthetically active radiation (PAR) but increasing density of smoke turned the oil palm plantation into a source of carbon. The turbulent heat fluxes experienced an increase in sensible heat fluxes due to drought conditions at the cost of latent heat fluxes resulting in an increase in the midday Bowen-ratio from 0.17 to 0.40. Strong smoke</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911292C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911292C"><span>Analysis of the <span class="hlt">ENSO</span> temperature and specific humidity signals in the troposphere and lower stratosphere with global COSMIC GPS RO observations from June 2006 to June 2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Zhiping; Luo, Jia</p> <p>2017-04-01</p> <p>The specific humidity and the temperature response of El Niño-Southern Oscillation in the troposphere and lower stratosphere (TLS) over different areas i.e., Niño 3.4 (N3.4); -5˚ S-5˚ N, 180˚ W-180˚ E (G5); -30˚ S-30˚ N, 180˚ W-180˚ E (G30); -60˚ S-60˚ N, 180˚ W-180˚ E (G60); -90˚ S-90˚ N, 180˚ W-180˚ E (G90) were investigated using Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) data from June 2006 to June 2014. The empirical orthogonal functions (EOFs) and band-pass filtering with different filtering ranges at different altitudes were used to extract the <span class="hlt">ENSO</span>-related signals of the specific humidity and the temperature over different altitude levels in the TLS. The time series that has the maximum correlation coefficient between the <span class="hlt">ENSO</span>-related signals and the ONI were regarded as the strongest response to <span class="hlt">ENSO</span>. The results confirmed that the <span class="hlt">ENSO</span> was originated from tropical Pacific Ocean. The lag time and the phase of the maximum specific humidity or temperature response to <span class="hlt">ENSO</span> event does not show a uniform patern at different altitudes in the troposphere over different areas, but the 1-2 seasons lag ONI was found and consistent with previous study results. The maximum correlation coefficient between the specific humidity and the ONI was about 0.94 at a lag time of 3 months at about 225 hpa altitude over the statistical areas while the maximum correlation coefficients (0.91) between the temperature and the ONI was found at ˜325 hpa altitude level at a lag time of 1 month in the TLS. The well agreement between the <span class="hlt">ENSO</span>-related signals in the troposphere and the ONI indicates that the specific humidity and temperature derived from COSMIC GPS RO observations are significant for monitoring the <span class="hlt">ENSO</span> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AtmRe.200..117L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AtmRe.200..117L"><span>Multi-scale linkages of winter drought variability to <span class="hlt">ENSO</span> and the Arctic Oscillation: A case study in Shaanxi, North China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Zhiyong; Zhang, Xin; Fang, Ruihong</p> <p>2018-02-01</p> <p>Understanding the potential connections between climate indices such as the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and Arctic Oscillation (AO) and drought variability will be beneficial for making reasonable predictions or assumptions about future regional droughts, and provide valuable information to improve water resources planning and design for specific regions of interest. This study is to examine the multi-scale relationships between winter drought variability over Shaanxi (North China) and both <span class="hlt">ENSO</span> and AO during the period 1960-2009. To accomplish this, we first estimated winter dryness/wetness conditions over Shaanxi based on the self-calibrating Palmer drought severity index (PDSI). Then, we identified the spatiotemporal variability of winter dryness/wetness conditions in the study area by using the empirical orthogonal function (EOF). Two primary sub-regions of winter dryness/wetness conditions across Shaanxi were identified. We further examined the periodical oscillations of dryness/wetness conditions and the multi-scale relationships between dryness/wetness conditions and both <span class="hlt">ENSO</span> and AO in winter using wavelet analysis. The results indicate that there are inverse multi-scale relations between winter dryness/wetness conditions and <span class="hlt">ENSO</span> (according to the wavelet coherence) for most of the study area. Moreover, positive multi-scale relations between winter dryness/wetness conditions and AO are mainly observed. The results could be beneficial for making reasonable predictions or assumptions about future regional droughts and provide valuable information to improve water resources planning and design within this study area. In addition to the current study area, this study may also offer a useful reference for other regions worldwide with similar climate conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..4312634J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..4312634J"><span><span class="hlt">ENSO</span> modulation of tropical Indian Ocean subseasonal variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, Eunsil; Kirtman, Ben P.</p> <p>2016-12-01</p> <p>In this study, we use 30 years of retrospective climate model forecasts and observational estimates to show that El Niño/Southern Oscillation (<span class="hlt">ENSO</span>) affects the amplitude of subseasonal variability of sea surface temperature (SST) in the southwest Indian Ocean, an important Tropical Intraseasonal Oscillation (TISO) onset region. The analysis shows that deeper background mixed-layer depths and warmer upper ocean conditions during El Niño reduce the amplitude of the subseasonal SST variability over Seychelles-Chagos Thermocline Ridge (SCTR), which may reduce SST-wind coupling and the amplitude of TISO variability. The opposite holds for La Niña where the shallower mixed-layer depth enhances SST variability over SCTR, which may increase SST-wind coupling and the amplitude of TISO variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29636483','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29636483"><span><span class="hlt">ENSO</span>-driven climate variability promotes periodic major outbreaks of dengue in Venezuela.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vincenti-Gonzalez, M F; Tami, A; Lizarazo, E F; Grillet, M E</p> <p>2018-04-10</p> <p>Dengue is a mosquito-borne viral disease of global impact. In Venezuela, dengue has emerged as one of the most important public health problems of urban areas with frequent epidemics since 2001. The long-term pattern of this disease has involved not only a general upward trend in cases but also a dramatic increase in the size and frequency of epidemic outbreaks. By assuming that climate variability has a relevant influence on these changes in time, we quantified the periodicity of dengue incidence in time-series of data from two northern regions of Venezuela. Disease cycles of 1 and 3-4 years (p < 0.05) were detected. We determined that dengue cycles corresponded with local climate and the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) variation at both seasonal and inter-annual scales (every 2-3 years). Dengue incidence peaks were more prevalent during the warmer and dryer years of El Niño confirming that <span class="hlt">ENSO</span> is a regional climatic driver of such long-term periodicity through local changes in temperature and rainfall. Our findings support the evidence of the effect of climate on dengue dynamics and advocate the incorporation of climate information in the surveillance and prediction of this arboviral disease in Venezuela.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015rtpm.book..173S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015rtpm.book..173S"><span>A New Technique to Observe <span class="hlt">ENSO</span> Activity via Ground-Based GPS Receivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suparta, Wayan; Iskandar, Ahmad; Singh, Mandeep Singh Jit</p> <p></p> <p>In an attempt to study the effects of global climate change in the tropics for improving global climate model, this paper aims to detect the <span class="hlt">ENSO</span> events, especially El Nino phase by using ground-based GPS receivers. Precipitable water vapor (PWV) obtained from the Global Positioning System (GPS) Meteorology measurements in line with the sea surface temperature anomaly (SSTa) are used to connect their response to El Niño activity. The data gathered from four selected stations over the Southeast Asia, namely PIMO (Philippines), KUAL (Malaysia), NTUS (Singapore) and BAKO (Indonesia) for the year of 2009/2010 were processed. A strong correlation was observed for PIMO station with a correlation coefficient of -0.90, significantly at the 99 % confidence level. In general, the relationship between GPS PWV and SSTa at all stations on a weekly basis showed with a negative correlation. The negative correlation indicates that during the El Niño event, the PWV variation was in decreased trend. Decreased trend of PWV value is caused by a dry season that affected the GPS signals in the ocean-atmospheric coupling. Based on these promising results, we can propose that the ground-based GPS receiver is capable used to monitor <span class="hlt">ENSO</span> activity and this is a new prospective method that previously unexplored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPP22A..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPP22A..08H"><span><span class="hlt">ENSO</span> variability of Quelccaya Ice Cap δ18O driven by monsoon control of vapor isotope ratios</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurley, J. V.; Vuille, M. F.; Hardy, D. R.</p> <p>2016-12-01</p> <p>The δ18O from the Quelccaya Ice Cap (QIC), Peru corresponds with and has been used to reconstruct Nino region SSTs but the physical mechanisms that tie <span class="hlt">ENSO</span>-variable equatorial Pacific SSTs to snow δ18O at 5680 m in the Andes have not been fully described. We use a proxy system forward model to simulate and explore <span class="hlt">ENSO</span> variable snow δ18O at the QIC, which is observed and accurately simulated with our model to be respectively higher and lower than average during El Nino and La Nina. We then explore the relative roles of <span class="hlt">ENSO</span>-forcing on components of the forward model: the seasonality of snowfall at the QIC, vapor initial δ18O values, and temperature. The local hydrologic cycle is characterized by earlier onset and reduced duration of peak snowfall during El Nino, and more snow accumulation during La Nina. When we isolate the influence of the local hydrologic cycle in the forward model, El Nino and La Nina snowfall seasonalities yield respectively higher and lower snow δ18O values, compared with the control simulation. The South American summer monsoon (SASM) is characterized by enhanced convection over the Amazon during La Nina and as a consequence, lower vapor δ18O values over the western Amazon Basin. When we isolate the influence of the vapor initial delta-value in the forward model, higher initial delta-values during El Nino yield higher snow δ18O at the QIC. The seasonality of temeratures over the western Amazon Basin and near Quelccaya is amplified during El Nino when there are higher and lower temperatures respectively during austral summer and winter. When we isolate the temperature influence in the forward model, the warmer summer El Nino conditions require a more humid initial vapor and result in lower snow δ18O values. Most (more than two-thirds) of the <span class="hlt">ENSO</span> variability in QIC δ18O can be accounted for by SASM activity and its influence on the vapor initial delta-value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NIMPA.796...93P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NIMPA.796...93P"><span><span class="hlt">aSi</span> EPIDs for the in-vivo dosimetry of static and dynamic beams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piermattei, A.; Cilla, S.; Azario, L.; Greco, F.; Russo, M.; Grusio, M.; Orlandini, L.; Fidanzio, A.</p> <p>2015-10-01</p> <p>Portal imaging by amorphous silicon (<span class="hlt">aSi</span>) photodiode is currently the most applied technology for in-vivo dosimetry (IVD) of static and dynamic radiotherapy beams. The strategy, adopted in this work to perform the IVD procedure by <span class="hlt">aSi</span> EPID, is based on: in patient reconstruction of the isocenter dose and day to day comparison between 2D-portal images to verify the reproducibility of treatment delivery. About 20.000 tests have been carried out in this last 3 years in 8 radiotherapy centers using the SOFTDISO program. The IVD results show that: (i) the procedure can be implemented for linacs of different manufacturer, (ii) the IVD analysis can be obtained on a computer screen, in quasi real time (about 2 min after the treatment delivery) and (iii) once the causes of the discrepancies were eliminated, all the global IVD tests for single patient were within the acceptance criteria defined by: ±5% for the isocenter dose, and Pγ<1≥90% of the checked points for the 2D portal image γ-analysis. This work is the result of a project supported by the Istituto Nazionale di Fisica Nucleare (INFN) and Università Cattolica del S.Cuore (UCSC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..12111486K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..12111486K"><span>Zonally resolved impact of <span class="hlt">ENSO</span> on the stratospheric circulation and water vapor entry values</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Konopka, Paul; Ploeger, Felix; Tao, Mengchu; Riese, Martin</p> <p>2016-10-01</p> <p>Based on simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) for the period 1979-2013, with model transport driven by the ECMWF ERA-Interim reanalysis, we discuss the impact of the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) on the variability of the dynamics, water vapor, ozone, and mean age of air (AoA) in the tropical lower stratosphere during boreal winter. Our zonally resolved analysis at the 390 K potential temperature level reveals that not only (deseasonalized) <span class="hlt">ENSO</span>-related temperature anomalies are confined to the tropical Pacific (180-300°E) but also anomalous wave propagation and breaking, as quantified in terms of the Eliassen-Palm (EP) flux divergence, with strongest local contribution during the La Niña phase. This anomaly is coherent with respective anomalies of water vapor (±0.5 ppmv) and ozone (±100 ppbv) derived from CLaMS being in excellent agreement with the Aura Microwave Limb Sounder observations. Thus, during El Niño a more zonally symmetric wave forcing drives a deep branch of the Brewer-Dobson (BD) circulation. During La Niña this forcing increases at lower levels (≈390 K) over the tropical Pacific, likely influencing the shallow branch of the BD circulation. In agreement with previous studies, wet (dry) and young (old) tape recorder anomalies propagate upward in the subsequent months following El Niño (La Niña). Using CLaMS, these anomalies are found to be around +0.3 (-0.2) ppmv and -4 (+4) months for water vapor and AoA, respectively. The AoA <span class="hlt">ENSO</span> anomaly is more strongly affected by the residual circulation (≈2/3) than by eddy mixing (≈1/3).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000086133','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000086133"><span>Evolution of Tropical and Extratropical Precipitation Anomalies During the 1997 to 1999 <span class="hlt">ENSO</span> Cycle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, Scott; Adler, Robert; Huffman, George; Nelkin, Eric; Bolvin, David; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>The 1997-1999 <span class="hlt">ENSO</span> period was very powerful, but also well observed. Multiple satellite rainfall estimates combined with gauge observations allow for a quantitative analysis of precipitation anomalies in the tropics and elsewhere accompanying the 1997-99 <span class="hlt">ENSO</span> cycle. An examination of the evolution of the El Nino and accompanying precipitation anomalies revealed that a dry Maritime Continent preceded the formation of positive SST anomalies in the eastern Pacific Ocean. 30-60 day oscillations in the winter of 1996/97 may have contributed to this lag relationship. Furthermore, westerly wind burst events may have maintained the drought over the Maritime Continent. The warming of the equatorial Pacific was then followed by an increase in convection. A rapid transition from El Nino to La Nina occurred in May 1998, but as early as October-November 1997 precipitation indices captured substantial changes in Pacific rainfall anomalies. The global precipitation patterns for this event were in good agreement with the strong consistent <span class="hlt">ENSO</span>-related precipitation signals identified in earlier studies. Differences included a shift in precipitation anomalies over Africa during the 1997-98 El Nino and unusually wet conditions over northeast Australia during the later stages of the El Nino. Also, the typically wet region in the north tropical Pacific was mostly dry during the 1998-99 La Nina. Reanalysis precipitation was compared to observations during this time period and substantial differences were noted. In particular, the model had a bias towards positive precipitation anomalies and the magnitudes of the anomalies in the equatorial Pacific were small compared to the observations. Also, the evolution of the precipitation field, including the drying of the Maritime Continent and eastward progression of rainfall in the equatorial Pacific was less pronounced for the model compared to the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMPP43A0603S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMPP43A0603S"><span>Reconstruction of the West Pacific <span class="hlt">ENSO</span> precipitation anomaly using the compound-specific hydrogen isotopic record of marine lake sediments of Palau</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smittenberg, R. H.; Sachs, J. P.; Dawson, M. N.</p> <p>2004-12-01</p> <p>There is still much uncertainty whether the El Niño Southern Oscillation (<span class="hlt">ENSO</span>) will become stronger or more frequent in a warming global climate. A principal reason for this uncertainty stems from a glaring lack of paleoclimate data in the equatorial Pacific, which hampers model validation. To partly resolve this data deficiency, sediments of three marine anoxic lakes were cored in Palau, an island group that lies in the heart of the West Pacific Warm Pool. The lakes contain seawater that seeps through fissures in the surrounding karst, and they are permanently stratified due to fresh water input provided by the year-round wet climate (map 1970-2000 = 3.7m). During <span class="hlt">ENSO</span> events, however, the islands suffer from drought. The surface water hydrogen isotopic compositions in the lakes are sensitive to the relative proportions of D-depleted rainwater and D-enriched seawater, and are therefore sensitive to <span class="hlt">ENSO</span> events. The lake surface water H/D values are recorded by algal and bacterial biomarkers that are preserved well in the highly organic and anoxic sediments, which accumulate relatively fast (mean 1 mm/yr). Ongoing down core measurement will eventually result in a precipitation proxy record of the islands. To obtain endmember D/H values, a comprehensive set of water samples from sea, lakes and rain water was obtained, as well as suspended particulate matter. Higher plant biomarker D/H values derived from the jungle vegetation surrounding the lakes may render supporting climatic proxy data, being influenced by evapotranspiration. Some lakes are inhabited by millions of jellyfish (Mastigias) that live in symbiosis with zooxanthellae. The jellyfish of one of the investigated lakes disappeared completely after the last large <span class="hlt">ENSO</span> event in 1998 (returning in 2000-01), and a correlation is suggested. To reconstruct the history of jellyfish occurrence, jellyfish and sedimentary lipids were extracted and compared. In addition to a possible <span class="hlt">ENSO</span> proxy record, this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4846189','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4846189"><span>The use of adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R) technique in evaluation of patients with cervical spine trauma: impact on radiation dose reduction and image quality</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sheikh, Adnan</p> <p>2016-01-01</p> <p>Objective: The aim of this study was to evaluate the impact of adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R) technique on the image quality and radiation dose reduction. The comparison was made with the traditional filtered back projection (FBP) technique. Methods: We retrospectively reviewed 78 patients, who underwent cervical spine CT for blunt cervical trauma between 1 June 2010 and 30 November 2010. 48 patients were imaged using traditional FBP technique and the remaining 30 patients were imaged using the <span class="hlt">ASi</span>R technique. The patient demographics, radiation dose, objective image signal and noise were recorded; while subjective noise, sharpness, diagnostic acceptability and artefacts were graded by two radiologists blinded to the techniques. Results: We found that the <span class="hlt">ASi</span>R technique was able to reduce the volume CT dose index, dose–length product and effective dose by 36%, 36.5% and 36.5%, respectively, compared with the FBP technique. There was no significant difference in the image noise (p = 0.39), signal (p = 0.82) and signal-to-noise ratio (p = 0.56) between the groups. The subjective image quality was minimally better in the <span class="hlt">ASi</span>R group but not statistically significant. There was excellent interobserver agreement on the subjective image quality and diagnostic acceptability for both groups. Conclusion: The use of <span class="hlt">ASi</span>R technique allowed approximately 36% radiation dose reduction in the evaluation of cervical spine without degrading the image quality. Advances in knowledge: The present study highlights that the <span class="hlt">ASi</span>R technique is extremely helpful in reducing the patient radiation exposure while maintaining the image quality. It is highly recommended to utilize this novel technique in CT imaging of different body regions. PMID:26882825</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26882825','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26882825"><span>The use of adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R) technique in evaluation of patients with cervical spine trauma: impact on radiation dose reduction and image quality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patro, Satya N; Chakraborty, Santanu; Sheikh, Adnan</p> <p>2016-01-01</p> <p>The aim of this study was to evaluate the impact of adaptive statistical iterative reconstruction (<span class="hlt">ASi</span>R) technique on the image quality and radiation dose reduction. The comparison was made with the traditional filtered back projection (FBP) technique. We retrospectively reviewed 78 patients, who underwent cervical spine CT for blunt cervical trauma between 1 June 2010 and 30 November 2010. 48 patients were imaged using traditional FBP technique and the remaining 30 patients were imaged using the <span class="hlt">ASi</span>R technique. The patient demographics, radiation dose, objective image signal and noise were recorded; while subjective noise, sharpness, diagnostic acceptability and artefacts were graded by two radiologists blinded to the techniques. We found that the <span class="hlt">ASi</span>R technique was able to reduce the volume CT dose index, dose-length product and effective dose by 36%, 36.5% and 36.5%, respectively, compared with the FBP technique. There was no significant difference in the image noise (p = 0.39), signal (p = 0.82) and signal-to-noise ratio (p = 0.56) between the groups. The subjective image quality was minimally better in the <span class="hlt">ASi</span>R group but not statistically significant. There was excellent interobserver agreement on the subjective image quality and diagnostic acceptability for both groups. The use of <span class="hlt">ASi</span>R technique allowed approximately 36% radiation dose reduction in the evaluation of cervical spine without degrading the image quality. The present study highlights that the <span class="hlt">ASi</span>R technique is extremely helpful in reducing the patient radiation exposure while maintaining the image quality. It is highly recommended to utilize this novel technique in CT imaging of different body regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS51A2024S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS51A2024S"><span>Contrasting <span class="hlt">ENSO</span> types with novel satellite derived ocean phytoplankton biomass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, P.; Singh, A. M.; Marinov, I.; Kostadinov, T. S.</p> <p>2016-12-01</p> <p>Observed variations in community structure and biogeochemical processes in the tropics and the North Atlantic have been linked, in the first order, to the El Niño Southern Oscillation phenomenon (e.g., Bates, 2001; Karl et al., 2001; Di Lorenzo et al., 2010; Di Lorenzo et al., 2013). Current significant technical advances have allowed for the retrieval of biological data from the optical properties of the water via satellite ocean color remote sensing, providing an opportunity for quantifying the relationships between biological and climate indices. Studies have focused in-depth on contrasting flavors of the <span class="hlt">ENSO</span> types with various physical (e.g., Singh et al. 2011; Turk et al. 2011) and biological (e.g., Radenac et al. 2012) indices. Here, we analyze the impact of different <span class="hlt">ENSO</span> types on biology via analysis of recently-derived backscattering-based biomass separated into size-groups (Kostadinov et al. 2010, 2016) over the 17-year (1997-2013). We further contrast the responses of biomass with those of chlorophyll (Chl) and particulate inorganic carbon (PIC). We analyze the complex spatial differences in both physical (SST, mixed layer depth, winds) and biological (Chl, total and size-partitioned biomass) variability across the Pacific warm pool and equatorial tongue via simple EOF, combined regression-EOF and Agglomerative Hierarchical Clustering (AHC) analysis. The interannual variability in the physical and biological fields show clear signatures of the Niño cold-tongue (NCT) and Niño warm pool (NWP). Possible mechanisms responsible for these signatures are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H43D1679S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H43D1679S"><span>Effect of Modulation of <span class="hlt">ENSO</span> by Decadal and Multidecadal Ocean-Atmospheric Oscillations on Continental US Streamflows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, S.; Abebe, A.; Srivastava, P.; Chaubey, I.</p> <p>2017-12-01</p> <p>Evaluation of the influences of individual and coupled oceanic-atmospheric oscillations on streamflow at a regional scale in the United States is the focus of this study. The main climatic oscillations considered in this study are: El Niño Southern Oscillation (<span class="hlt">ENSO</span>), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and North Atlantic Oscillation (NAO). Unimpacted or minimally impacted by water management streamflow data from the Model Parameter Estimation Experiment (MOPEX) were used in this study. Two robust and novel non-parametric tests, namely, the rank based partial least square (PLS) and the Joint Rank Fit (JRFit) procedures were used to identify the individual and coupled effect of oscillations on streamflow across continental U.S. (CONUS), respectively. Moreover, the interactive effects of <span class="hlt">ENSO</span> with decadal and multidecadal cycles were tested and quantified using the JRFit interaction test. The analysis of <span class="hlt">ENSO</span> indicated higher streamflows during La Niña phase compared to the El Niño phase in Northwest, Northeast and the lower part of Ohio Valley while the opposite occurs for rest of the climatic regions in US. Two distinct climate regions (Northwest and Southeast) were identified from the PDO analysis where PDO negative phase results in increased streamflow than PDO positive phase. Consistent negative and positive correlated regions around the CONUS were identified for AMO and NAO, respectively. The interaction test of <span class="hlt">ENSO</span> with decadal and multidecadal oscillations showed that El Niño is modulated by the negative phase of PDO and NAO, and the positive phase of AMO, respectively, in the Upper Midwest. However, La Niña is modulated by the positive phase of AMO and PDO in Ohio Valley and Northeast while in Southeast and the South it is modulated by AMO negative phase. Results of this study will assist water managers to understand the streamflow change patterns across the CONUS at decadal and multi-decadal time scales. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19267731','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19267731"><span>Patients' perceptions and experiences of using a mobile phone-based advanced symptom management system (<span class="hlt">ASy</span>MS) to monitor and manage chemotherapy related toxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCann, L; Maguire, R; Miller, M; Kearney, N</p> <p>2009-03-01</p> <p>Chemotherapy forms a core component of treatment for the majority patients with cancer. Recent changes in cancer services mean patients frequently receive such treatment as outpatients and are often required to manage side effects at home without direct support from oncology health professionals. Information technology continues to develop to support patients in the community; this study evaluated the impact of a mobile phone-based advanced symptom management system (<span class="hlt">ASy</span>MS) on chemotherapy related toxicity in patients with lung, breast or colorectal cancer. One hundred and twelve patients were randomized from seven clinical sites across the UK; 56 patients used the mobile phone to record their symptoms, sending their reports directly to the nurses at their clinical site; 56 control group patients received standard care. Health professionals were alerted about any severe or life-threatening symptoms through the development of a chemotherapy symptom risk model. Patients' perceptions of <span class="hlt">ASy</span>MS were evaluated pre and post participation. Patients reported many benefits of using <span class="hlt">ASy</span>MS including improved communication with health professionals, improvements in the management of their symptoms, and feeling reassured their symptoms were being monitored while at home. <span class="hlt">ASy</span>MS has the potential to positively impact on the management of symptoms in patients receiving chemotherapy treatment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9431L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9431L"><span>What do we need to know to predict <span class="hlt">ENSO</span>? Student-centered learning in a Master course in Climate Physics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lübbecke, Joke; Glessmer, Mirjam</p> <p>2017-04-01</p> <p>An important learning outcome of a Master of Sciences program is to empower students to understand which information they need, how they can gain the required knowledge and skills, and how to apply those to solve a given scientific problem. In designing a class on the El-Nino-Southern-Oscillation (<span class="hlt">ENSO</span>) for students in the Climate Physics program at Kiel University, Germany, we have implemented various active learning strategies to meet this goal. The course is guided by an overarching question, embedded in a short story: What would we need to know to successfully predict <span class="hlt">ENSO</span>? The students identify desired learning outcomes and collaboratively construct a concept map which then serves as a structure for the 12 weeks of the course, where each individual topic is situated in the larger context of the students' own concept map. Each learning outcome of the course is therefore directly motivated by a need to know expressed by the students themselves. During each session, students are actively involved in the learning process. They work individually or in small groups, for example testing different index definitions, analyzing data sets, setting up simple numerical models and planning and constructing hands-on experiments to demonstrate physical processes involved in the formation of El Niño events. The instructor's role is to provide the necessary background information and guide the students where it is needed. Insights are shared between groups as students present their findings to each other and combine the information, for example by cooperatively constructing a world map displaying the impacts of <span class="hlt">ENSO</span> or by exchanging experts on different <span class="hlt">ENSO</span> oscillator theories between groups. Development of this course was supported by the PerLe Fonds for teaching innovations at Kiel University. A preliminary evaluation has been very positive with students in particular appreciating their active involvement in the class.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A11R..07H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A11R..07H"><span>Anomalously Strong and Rapid Drying of the Tropical Lower Stratosphere in 2016: Connections to Both the QBO and <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurst, D. F.; Davis, S. M.; Rosenlof, K. H.; Lambert, A.; Read, W. G.; Hall, E.; Jordan, A. F.</p> <p>2017-12-01</p> <p>Variations in tropical lower stratospheric water vapor are generally attributable to annual cycles in the Brewer-Dobson circulation and inter-annual phenomenon like the quasi-biennial oscillation (QBO) and the El Niño Southern Oscillation (<span class="hlt">ENSO</span>). Extremes in tropical lower stratospheric water vapor (SWV) occur when these annual and inter-annual changes are constructively superimposed. The atypical progression of the 2015-16 QBO led to a strong and rapid cooling of the tropical lower stratosphere during 2016. From December 2015 to November 2016, monthly tropical mean (15°S-15°N) coldpoint temperature (CPT) anomalies decreased 3.2°C, from 1.1 to -2.1°C. Accordingly, monthly tropical mean SWV anomalies at 83 hPa dropped 1.9 ppm, from 0.85 to -1.05 ppm. This decline in SWV anomalies is equivalent to 40% of the long-term December average tropical abundance of SWV at 83 hPa. The 2016 decreases in tropical anomalies of both CPTs and SWV were not zonally uniform, with average Eastern Hemisphere reductions greater by 2°C and 0.9 ppm (50%), respectively. Since the QBO typically has a zonally uniform effect on tropical CPTs, this implies a zonally non-uniform mechanism like <span class="hlt">ENSO</span> also influenced CPTs during 2016. The transition of <span class="hlt">ENSO</span> from strong El Niño to weak La Niña conditions in 2016 would induce this zonal non-uniformity by shifting convective activity from the Eastern Pacific to the Western Pacific and Indian Ocean regions. Evidence indicates the simultaneous cooling of tropical CPTs by both the QBO and <span class="hlt">ENSO</span> during 2016 rapidly dried the tropical lower stratosphere with anomalous strength, especially in the Eastern Hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29745100','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29745100"><span>Comparative performance evaluation of a new <span class="hlt">a-Si</span> EPID that exceeds quad high-definition resolution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McConnell, Kristen A; Alexandrian, Ara; Papanikolaou, Niko; Stathakis, Sotiri</p> <p>2018-01-01</p> <p>Electronic portal imaging devices (EPIDs) are an integral part of the radiation oncology workflow for treatment setup verification. Several commercial EPID implementations are currently available, each with varying capabilities. To standardize performance evaluation, Task Group Report 58 (TG-58) and TG-142 outline specific image quality metrics to be measured. A LinaTech Image Viewing System (IVS), with the highest commercially available pixel matrix (2688x2688 pixels), was independently evaluated and compared to an Elekta iViewGT (1024x1024 pixels) and a Varian <span class="hlt">aSi</span>-1000 (1024x768 pixels) using a PTW EPID QC Phantom. The IVS, iViewGT, and <span class="hlt">aSi</span>-1000 were each used to acquire 20 images of the PTW QC Phantom. The QC phantom was placed on the couch and aligned at isocenter. The images were exported and analyzed using the epidSoft image quality assurance (QA) software. The reported metrics were signal linearity, isotropy of signal linearity, signal-tonoise ratio (SNR), low contrast resolution, and high-contrast resolution. These values were compared between the three EPID solutions. Computed metrics demonstrated comparable results between the EPID solutions with the IVS outperforming the <span class="hlt">aSi</span>-1000 and iViewGT in the low and high-contrast resolution analysis. The performance of three commercial EPID solutions have been quantified, evaluated, and compared using results from the PTW QC Phantom. The IVS outperformed the other panels in low and high-contrast resolution, but to fully realize the benefits of the IVS, the selection of the monitor on which to view the high-resolution images is important to prevent down sampling and visual of resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS13A1804Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS13A1804Q"><span><span class="hlt">ENSO</span> related sea surface salinity variability in the equatorial Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qu, T.</p> <p>2016-12-01</p> <p>Recently available satellite and Argo data have shown coherent, large-scale sea surface salinity (SSS) variability in the equatorial Pacific. Based on this variability, several SSS indices of El Nino have been introduced by previous studies. Combining results from an ocean general circulation model with available satellite and in-situ observations, this study investigates the SSS variability and its associated SSS indices in the equatorial Pacific. The ocean's role and in particular the vertical entrainment of subtropical waters in this variability are discussed, which suggests that the SSS variability in the equatorial Pacific may play some active role in <span class="hlt">ENSO</span> evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.9107H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.9107H"><span>Exploring the combined effects of the Arctic Oscillation and <span class="hlt">ENSO</span> on the wintertime climate over East Asia using self-organizing maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Wenyu; Chen, Ruyan; Yang, Zifan; Wang, Bin; Ma, Wenqian</p> <p>2017-09-01</p> <p>To examine the combined effects of the different spatial patterns of the Arctic Oscillation (AO)-related sea level pressure (SLP) anomalies and the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>)-related sea surface temperature (SST) anomalies on the wintertime surface temperature anomalies over East Asia, a nonlinear method based on self-organizing maps is employed. Investigation of identified regimes reveals that the AO can affect East Asian temperature anomalies when there are significant SLP anomalies over the Arctic Ocean and northern parts of Eurasian continent. Analogously, <span class="hlt">ENSO</span> is found to affect East Asian temperature anomalies when significant SST anomalies are present over the tropical central Pacific. The regimes with the warmest and coldest temperature anomalies over East Asia are both associated with the negative phase of the AO. The <span class="hlt">ENSO</span>-activated, Pacific-East Asian teleconnection pattern could affect the higher latitude continental regions when the impact of the AO is switched off. When the spatial patterns of the AO and <span class="hlt">ENSO</span> have significant, but opposite, impacts on the coastal winds, no obvious temperature anomalies can be observed over south China. Further, the circulation state with nearly the same AO and Niño3 indices may drive rather different responses in surface temperature over East Asia. The well-known continuous weakening (recovery) of the East Asian winter monsoon that occurred around 1988 (2009) can be attributed to the transitions of the spatial patterns of the SLP anomalies over the Arctic Ocean and Eurasian continent, through their modulation on the occurrences of the Ural and central Siberian blocking events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ThApC.132..465R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ThApC.132..465R"><span>Diversity in the representation of large-scale circulation associated with <span class="hlt">ENSO</span>-Indian summer monsoon teleconnections in CMIP5 models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramu, Dandi A.; Chowdary, Jasti S.; Ramakrishna, S. S. V. S.; Kumar, O. S. R. U. B.</p> <p>2018-04-01</p> <p>Realistic simulation of large-scale circulation patterns associated with El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is vital in coupled models in order to represent teleconnections to different regions of globe. The diversity in representing large-scale circulation patterns associated with <span class="hlt">ENSO</span>-Indian summer monsoon (ISM) teleconnections in 23 Coupled Model Intercomparison Project Phase 5 (CMIP5) models is examined. CMIP5 models have been classified into three groups based on the correlation between Niño3.4 sea surface temperature (SST) index and ISM rainfall anomalies, models in group 1 (G1) overestimated El Niño-ISM teleconections and group 3 (G3) models underestimated it, whereas these teleconnections are better represented in group 2 (G2) models. Results show that in G1 models, El Niño-induced Tropical Indian Ocean (TIO) SST anomalies are not well represented. Anomalous low-level anticyclonic circulation anomalies over the southeastern TIO and western subtropical northwest Pacific (WSNP) cyclonic circulation are shifted too far west to 60° E and 120° E, respectively. This bias in circulation patterns implies dry wind advection from extratropics/midlatitudes to Indian subcontinent. In addition to this, large-scale upper level convergence together with lower level divergence over ISM region corresponding to El Niño are stronger in G1 models than in observations. Thus, unrealistic shift in low-level circulation centers corroborated by upper level circulation changes are responsible for overestimation of <span class="hlt">ENSO</span>-ISM teleconnections in G1 models. Warm Pacific SST anomalies associated with El Niño are shifted too far west in many G3 models unlike in the observations. Further large-scale circulation anomalies over the Pacific and ISM region are misrepresented during El Niño years in G3 models. Too strong upper-level convergence away from Indian subcontinent and too weak WSNP cyclonic circulation are prominent in most of G3 models in which <span class="hlt">ENSO</span>-ISM teleconnections are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3861369','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3861369"><span>Effects of <span class="hlt">ENSO</span> and Temporal Rainfall Variation on the Dynamics of Successional Communities in Old-Field Succession of a Tropical Dry Forest</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Maza-Villalobos, Susana; Poorter, Lourens; Martínez-Ramos, Miguel</p> <p>2013-01-01</p> <p>The effects of temporal variation of rainfall on secondary succession of tropical dry ecosystems are poorly understood. We studied effects of inter-seasonal and inter-year rainfall variation on the dynamics of regenerative successional communities of a tropical dry forest in Mexico. We emphasized the effects caused by the severe El Niño Southern Oscillation (<span class="hlt">ENSO</span>) occurred in 2005. We established permanent plots in sites representing a chronosequence of Pasture (abandoned pastures, 0–1 years fallow age), Early (3–5), Intermediate (8–12), and Old-Growth Forest categories (n = 3 per category). In total, 8210 shrubs and trees 10 to 100-cm height were identified, measured, and monitored over four years. Rates of plant recruitment, growth and mortality, and gain and loss of species were quantified per season (dry vs. rainy), year, and successional category, considering whole communities and separating seedlings from sprouts and shrubs from trees. Community rates changed with rainfall variation without almost any effect of successional stage. Mortality and species loss rates peaked during the <span class="hlt">ENSO</span> year and the following year; however, after two rainy years mortality peaked in the rainy season. Such changes could result from the severe drought in the <span class="hlt">ENSO</span> year, and of the outbreak of biotic agents during the following rainy years. Growth, recruitment and species gain rates were higher in the rainy season but they were significantly reduced after the <span class="hlt">ENSO</span> year. Seedlings exhibited higher recruitment and mortality rate than sprouts, and shrubs showed higher recruitment than trees. <span class="hlt">ENSO</span> strongly impacted both the dynamics and trajectory of succession, creating transient fluctuations in the abundance and species richness of the communities. Overall, there was a net decline in plant and species density in most successional stages along the years. Therefore, strong drought events have critical consequences for regeneration dynamics, delaying the successional process</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/55476','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/55476"><span>Relationships of the symmetric and asymmetric components of <span class="hlt">ENSO</span> to US extreme precipitation</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Lejiang Yu; Warren E. Heilman; Shiyuan Zhong; Xindi Bian</p> <p>2017-01-01</p> <p>We used 35-year (1979–2013) hourly rainfall data from theNorth American LandData Assimilation System (NLDAS-2) to examine the relationships of the symmetric and asymmetric components of two types of El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) (El Niño and ElNiño Modoki) episodes with occurrences of extreme precipitation events across the United States. During the cold season,...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1916970M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1916970M"><span>Mechanisms of the global electric circuit and lightning variability on the <span class="hlt">ENSO</span> time scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mareev, Evgeny; Volodin, Evgeny; Slyunyaev, Nikolay</p> <p>2017-04-01</p> <p>Many studies of lightning activity on the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) time scale show increased activity over tropical land areas during the warm El Niño phase (e.g., Satori et al., 2009; Price, 2009). The mechanisms of this variability—particularly in terms of its role in the global electric circuit (GEC)—are still under debate (e.g., Williams and Mareev, 2014). In this study a general circulation model of the atmosphere and ocean INMCM4.0 (Institute of Numerical Mathematics Coupled Model) is used for modelling the GEC variability on the <span class="hlt">ENSO</span> time scale. The ionospheric potential (IP) and the lightning flash rate are calculated to study regional peculiarities and possible mechanisms of lightning variation. The IP parameterisation is used (Mareev and Volodin, 2014) which takes into account quasi-stationary currents of electrified clouds (including thunderstorms) as principal contributors into the DC global circuit. The account of conductivity variation in the IP parameterisation is suggested based on the approach realised in (Slyunyaev et al., 2014). Comparison of simulation results with the observational data on lightning activity on the <span class="hlt">ENSO</span> time scale is discussed. Numerical simulations suggest that the inter-annual IP variability is low and does not exceed 1% of the mean value, being tightly correlated with the mean sea surface temperature (SST) in the Pacific Ocean (180W-100W, 5S-5N—El Niño area). The IP maximum corresponds to the SST minimum. This result can be explained taking into account that during El Niño (positive temperature anomaly) precipitations in the equatorial part of the Pacific increase while in other tropic zones including the land areas they decrease. Comparison of simulation results with the observational data on lightning activity on the <span class="hlt">ENSO</span> time scale is discussed. During the El Niño period in the model, the mean aerosol content in the atmosphere decrease, which is caused by the weakening of the winds over Sahara and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRD..11216107J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRD..11216107J"><span>Subregional precipitation climate of the Caribbean and relationships with <span class="hlt">ENSO</span> and NAO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jury, Mark; Malmgren, BjöRn A.; Winter, Amos</p> <p>2007-08-01</p> <p>Thirty-five meteorological stations encompassing the Caribbean region (Cuba, Bahamas, Jamaica, Dominican Republic, Puerto Rico, US Virgin Islands, St. Maarten, and Barbados) were analyzed over the time interval 1951-1981 to assess regional precipitation patterns and their relationships with the North Atlantic Oscillation (NAO) and El Niño-Southern Oscillation (<span class="hlt">ENSO</span>). Application of factor analysis to these series revealed the existence of four geographically distinct precipitation regions, (C1) western Cuba and northwestern Bahamas, (C2) Jamaica, eastern Cuba, and southeastern Bahamas, (C3) Dominican Republic and northwestern Puerto Rico, and (C4) eastern Puerto Rico, US Virgin Islands, St. Maarten, and Barbados. This regionalization is related to different annual cycles and interannual fluctuations of rainfall. The annual cycle is more unimodal and largest in the northwest Caribbean (C1) and becomes increasingly bimodal toward lower latitudes (C4) as expected. Year-to-year variations of precipitation are compared with two well-known climatic indices. The <span class="hlt">ENSO</span> relationship, represented by Niño 3.4 sea surface temperatures (SST), is positive and stable at all lags, but tends to reverse over the SE Caribbean (C4) in late summer. The NAO influence is weak and seasonally dependent. Early summer rainfall in the northwest Caribbean (C1) increases under El Niño conditions. Clusters 2 and 3 are less influenced by the global predictors and more regional in character.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18953579','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18953579"><span>Evaluation of a mobile phone-based, advanced symptom management system (<span class="hlt">ASy</span>MS) in the management of chemotherapy-related toxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kearney, N; McCann, L; Norrie, J; Taylor, L; Gray, P; McGee-Lennon, M; Sage, M; Miller, M; Maguire, R</p> <p>2009-04-01</p> <p>To evaluate the impact of a mobile phone-based, remote monitoring, advanced symptom management system (<span class="hlt">ASy</span>MS) on the incidence, severity and distress of six chemotherapy-related symptoms (nausea, vomiting, fatigue, mucositis, hand-foot syndrome and diarrhoea) in patients with lung, breast or colorectal cancer. A two group (intervention and control) by five time points (baseline, pre-cycle 2, pre-cycle 3, pre-cycle 4 and pre-cycle 5) randomised controlled trial. Seven clinical sites in the UK; five specialist cancer centres and two local district hospitals. One hundred and twelve people with breast, lung or colorectal cancer receiving outpatient chemotherapy. A mobile phone-based, remote monitoring, advanced symptom management system (<span class="hlt">ASy</span>MS). Chemotherapy-related morbidity of six common chemotherapy-related symptoms (nausea, vomiting, fatigue, mucositis, hand-foot syndrome and diarrhoea). There were significantly higher reports of fatigue in the control group compared to the intervention group (odds ratio = 2.29, 95%CI = 1.04 to 5.05, P = 0.040) and reports of hand-foot syndrome were on average lower in the control group (odds ratio control/intervention = 0.39, 95%CI = 0.17 to 0.92, P = 0.031). The study demonstrates that <span class="hlt">ASy</span>MS can support the management of symptoms in patients with lung, breast and colorectal cancer receiving chemotherapy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B31G0546S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B31G0546S"><span>The impact of the 2015-2016 El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) event on greenhouse gas exchange and surface energy budget in an Indonesian oil palm plantation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stiegler, C.; Meijide, A.; June, T.; Knohl, A.</p> <p>2016-12-01</p> <p>Oil palm plantations cover a large fraction of tropical lowlands in Southeast Asia. However, despite their growing areal extent, measurements and observations of greenhouse gas exchange and surface energy balance are still scarce. In addition, the effects of extreme events such as El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) on carbon sequestration and the partitioning of surface energy balance components are widely unknown. In this study, we use micrometeorological measurements located in commercial oil palm plantations in the Jambi province (Sumatra, Indonesia) to assess the impact of the 2015-2016 <span class="hlt">ENSO</span> event on greenhouse gas exchange and surface energy budget. Measurements are in operation since July 2013 and we assess continuously turbulent fluxes of carbon dioxide (CO2), water vapour and sensible heat using the eddy covariance technique before, during and after the 2015-2016 <span class="hlt">ENSO</span> event. The full surface energy budget is completed by measurements of radiative components, ground heat fluxes, and soil thermal and hydrological properties. The study is part of a large interdisciplinary project focussing on the ecological and socioeconomic functions of lowland rainforest transformation systems (EFForTS). During the <span class="hlt">ENSO</span> event, the area experienced a strong drought with decreasing soil moisture and increasing air and surface temperatures. During the peak in September and October 2015, hundreds of fires in the area resulted in strong smoke production decreasing incoming solar radiation and increasing the diffuse fraction. Compared to regular years, the carbon uptake of the oil palm plantation decreased during the <span class="hlt">ENSO</span> event. The turbulent heat fluxes experienced an increase in sensible heat fluxes due to drought conditions at the cost of latent heat fluxes resulting in an increase in the Bowen-ratio. Overall, the <span class="hlt">ENSO</span> event resulted in a major anomaly of exchange processes between the oil palm plantation and the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMPP53B1127C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMPP53B1127C"><span>Precipitation and ice core isotopes from the Asian Summer Monsoon region reflect coherent <span class="hlt">ENSO</span> variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Z.; Tian, L.; Bowen, G. J.</p> <p>2017-12-01</p> <p>Oxygen isotope signals (δ18O) from paleo-archives are important proxies for past Asian Summer Monsoon (ASM) climate reconstruction. However, causes of interannual variation in the δ18O values of modern precipitation across the ASM region remain in argument. We report interannual δ18O variation in southern Tibetan Plateau precipitation based on long-term observations at Lhasa. These data, together with precipitation δ18O records from five Global Network of Isotopes in Precipitation (GNIP) stations and two ice core δ18O records, were used to define a regional metric of ASM precipitation δ18O (ASMOI). Back-trajectory analyses for rainy season precipitation events indicate that moisture sources vary little between years with relatively high and low δ18O values, a result that is consistent for the south (Lhasa), southeast (Bangkok), and east ASM regions (Hong Kong). In contrast, δ18O values at these three locations are significantly correlated with convection in the estimated source regions and along transport paths. These results suggest that upstream convection, rather than moisture source change, causes interannual variation in ASM precipitation δ18O values. Contrasting values of the ASMOI in El Niño and La Niña years reveal a positive isotope-El Niño Southern Oscillation (<span class="hlt">ENSO</span>) response (e.g., high values corresponding to warm phases), which we interpret as a response to changes in regional convection. We show that the isotope-<span class="hlt">ENSO</span> response is amplified at high elevation sites and during La Niña years. These findings should improve interpretations of paleo-δ18O data as a proxy for past ASM variation and provide new opportunities to use data from this region to study paleo-<span class="hlt">ENSO</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70022697','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70022697"><span>Predicting and downscaling <span class="hlt">ENSO</span> impacts on intraseasonal precipitation statistics in California: The 1997/98 event</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Gershunov, A.; Barnett, T.P.; Cayan, D.R.; Tubbs, T.; Goddard, L.</p> <p>2000-01-01</p> <p>Three long-range forecasting methods have been evaluated for prediction and downscaling of seasonal and intraseasonal precipitation statistics in California. Full-statistical, hybrid-dynamical - statistical and full-dynamical approaches have been used to forecast El Nin??o - Southern Oscillation (<span class="hlt">ENSO</span>) - related total precipitation, daily precipitation frequency, and average intensity anomalies during the January - March season. For El Nin??o winters, the hybrid approach emerges as the best performer, while La Nin??a forecasting skill is poor. The full-statistical forecasting method features reasonable forecasting skill for both La Nin??a and El Nin??o winters. The performance of the full-dynamical approach could not be evaluated as rigorously as that of the other two forecasting schemes. Although the full-dynamical forecasting approach is expected to outperform simpler forecasting schemes in the long run, evidence is presented to conclude that, at present, the full-dynamical forecasting approach is the least viable of the three, at least in California. The authors suggest that operational forecasting of any intraseasonal temperature, precipitation, or streamflow statistic derivable from the available records is possible now for <span class="hlt">ENSO</span>-extreme years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DyAtO..76...93J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DyAtO..76...93J"><span>Teleconnections of <span class="hlt">ENSO</span> and IOD to summer monsoon and rice production potential of India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jha, Somnath; Sehgal, Vinay Kumar; Raghava, Ramesh; Sinha, Mourani</p> <p>2016-12-01</p> <p>Regional trend of summer monsoon precipitation has been analyzed for broad physical regions of India namely, (i) Indo-Gangetic plain, (ii) Central and East India, (iii) Coastal and Peninsular India and (iv) Western India. A significantly drying trend has been found in the two regions namely, Indo-Gangetic plain and Central and East India with comparative seasonal rate of drying higher in the latter region. A complex relation between the regional trend of summer monsoon precipitation, global teleconnection parameters and rice production of the regions have been studied. El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and Indian Ocean dipole (IOD) have a significant role in the precipitation anomaly of Indo-Gangetic plain unlike Central and East India where the <span class="hlt">ENSO</span> only plays role as global teleconnection parameter. Rice production of Central and East India has been found to be affected adversely during the El Nino years. Central and East India is found to be the worst affected region compared to the Indo-Gangetic plain with respect to its fragile rainfed rice production potential and strong adverse teleconnection of El Nino on the rice production in this zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.1643C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.1643C"><span>The influence of <span class="hlt">ENSO</span> on an oceanic eddy pair in the South China Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Xiaoqing; Dong, Changming; Qi, Yiquan</p> <p>2017-03-01</p> <p>An eddy pair off the Vietnam coast is one of the most important features of the summertime South China Sea circulation. Its variability is of interest due to its profound impact on regional climate, ecosystems, biological processes, and fisheries. This study examines the influence of the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), a basin-scale climatic mode, on the interannual variability of this regional eddy pair using satellite observational data and historical hydrographic measurements. Over the last three decades, the eddy pair strengthened in 1994 and 2002, and weakened in 2006, 2007, and 2008. It was absent in 1988, 1995, 1998, and 2010, coinciding with strong El Nino-to-La Nina transitions. Composite analyses showed that the strong transition events of <span class="hlt">ENSO</span> led to radical changes in the summer monsoon, through the forcing of a unique sea surface temperature anomaly structure over the tropical Indo-Pacific basin. With weaker zonal wind, a more northward wind direction, and the disappearance of a pair of positive and negative wind stress curls, the eastward current jet turns northward along the Vietnam coast and the eddy pair disappears.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24200104','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24200104"><span>Changes in quality of life (WHOQOL-BREF) and addiction severity index (<span class="hlt">ASI</span>) among participants in opioid substitution treatment (OST) in low and middle income countries: an international systematic review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Feelemyer, Jonathan P; Jarlais, Don C Des; Arasteh, Kamyar; Phillips, Benjamin W; Hagan, Holly</p> <p>2014-01-01</p> <p>Opioid substitution treatment (OST) can increase quality of life (WHOQOL-BREF) and reduce addiction severity index (<span class="hlt">ASI</span>) scores among participants over time. OST program participants have noted that improvement in quality of life is one of the most important variables to their reduction in drug use. However, there is little systematic understanding of WHOQOL-BREF and <span class="hlt">ASI</span> domain changes among OST participants in low and middle-income countries (LMIC). Utilizing PRISMA guidelines we conducted a systematic literature search to identify OST program studies documenting changes in WHOQOL-BREF or <span class="hlt">ASI</span> domains for participants in buprenorphine or methadone programs in LMIC. Standardized mean differences for baseline and follow-up domain scores were compared along with relationships between domain scores, OST dosage, and length of follow-up. There were 13 OST program studies with 1801 participants from five countries eligible for inclusion in the review. Overall, statistically significant changes were noted in all four WHOQOL-BREF domain and four of the seven <span class="hlt">ASI</span> domain scores (drug, psychological, legal, and family) documented in studies. Dosage of pharmacologic medication and length of follow-up did not affect changes in domain scores. WHOQOL-BREF and <span class="hlt">ASI</span> domain scoring is a useful tool in measuring overall quality of life and levels of addiction among OST participants. Coupled with measurements of blood-borne infection, drug use, relapse, and overdose, WHOQOL-BREF and <span class="hlt">ASI</span> represent equally important tools for evaluating the effects of OST over time and should be further developed as integrated tools in the evaluation of participants in LMIC. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3984P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3984P"><span><span class="hlt">ASI</span>/CGS products and services in support of GNSS-meteorology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pacione, Rosa; Pace, Brigida; Bianco, Giuseppe</p> <p>2013-04-01</p> <p>For more than a decade, <span class="hlt">ASI</span>/CGS has supported ground-based GNSS meteorology in Europe participating in various projects such as MAGIC, COST-716, TOUGH, E-GVAP (phase I and II) and providing Zenith Tropospheric path Delays (ZTD) derived from a European network of GNSS stations covering mainly the central Mediterranean area. Working in close cooperation with the meteorological community, GNSS data are analyzed in order to provide ZTD with different latencies ranging from post-processing, useful for climate studies, to near-real time, for hourly assimilation into Numerical Weather Prediction (NWP) model. However advancements in NWP models (such as the Met Office UKV 1.5km model) with rapid update cycles require observations with improved timeliness and with greater spatial and temporal resolution than is currently available. To fulfil this requirement a sub-hourly PPP processing has been set-up, and is under evaluation, thanks to the availability of the IGS RT orbit and clock corrections. Moreover ZTD estimates are the input data for developing new and enhanced products: ZTD residuals fields and Integrated Water Vapour (IWV) maps. The former will be helpful in augmenting empirical tropospheric models for positioning applications. The latter are useful for nowcasting and severe weather monitoring since they let to follow IWV time evolution. We present an overview of the developed products and services; the new directions in support of NWP applications and the nowcasting and forecasting of severe weather events that emerge within E-GVAP phase III and the EU COST Action "Advanced Global Navigation Satellite Systems tropospheric products for monitoring Severe Weather Events and Climate" (GNSS4SWEC). Acknowledgements. This work has been carried out under <span class="hlt">ASI</span> contract I-014-10-0.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12698354','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12698354"><span>An examination of scale of assessment, logging and <span class="hlt">ENSO</span>-induced fires on butterfly diversity in Borneo.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cleary, Daniel F R</p> <p>2003-04-01</p> <p>The impact of disturbance on species diversity may be related to the spatial scales over which it occurs. Here I assess the impact of logging and <span class="hlt">ENSO</span> (El Niño Southern Oscillation) -induced burning and forest isolation on the species richness (477 species out of more than 28,000 individuals) and community composition of butterflies and butterfly guilds using small (0.9 ha) plots nested within large (450 ha) landscapes. The landscapes were located in three habitat classes: (1) continuous, unburned forest; (2) unburned isolates surrounded by burned forest; and (3) burned forest. Plots with different logging histories were sampled within the two unburned habitat classes, allowing for independent assessment of the two disturbance factors (logging and burning). Disturbance within habitat classes (logging) had a very different impact on butterfly diversity than disturbance among habitat classes (due to <span class="hlt">ENSO</span>-induced burning and isolation). Logging increased species richness, increased evenness, and lowered dominance. Among guilds based on larval food plants, the species richness of tree and herb specialists was higher in logged areas but their abundance was lower. Both generalist species richness and abundance was higher in logged areas. Among habitat classes, species richness was lower in burned forest and isolates than continuous forest but there was no overall difference in evenness or dominance. Among guilds, generalist species richness was significantly lower in burned forest and isolates than continuous forest. Generalist abundance was also very low in the isolates. There was no difference among disturbance classes in herb specialist species richness but abundance was significantly higher in the isolates and burned forest than in continuous forest. Tree specialist species richness was lower in burned forest than continuous forest but did not differ between continuous forest and isolates. The scale of assessment proved important in estimating the impact of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1610644V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1610644V"><span>Significant influences of global mean temperature and <span class="hlt">ENSO</span> on extreme rainfall over Southeast Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Villafuerte, Marcelino, II; Matsumoto, Jun</p> <p>2014-05-01</p> <p>Along with the increasing concerns on the consequences of global warming, and the accumulating records of disaster related to heavy rainfall events in Southeast Asia, this study investigates whether a direct link can be detected between the rising global mean temperature, as well as the El Niño-Southern Oscillation (<span class="hlt">ENSO</span>), and extreme rainfall over the region. The maximum likelihood modeling that allows incorporating covariates on the location parameter of the generalized extreme value (GEV) distribution is employed. The GEV model is fitted to annual and seasonal rainfall extremes, which were taken from a high-resolution gauge-based gridded daily precipitation data covering a span of 57 years (1951-2007). Nonstationarities in extreme rainfall are detected over the central parts of Indochina Peninsula, eastern coasts of central Vietnam, northwest of the Sumatra Island, inland portions of Borneo Island, and on the northeastern and southwestern coasts of the Philippines. These nonstationarities in extreme rainfall are directly linked to near-surface global mean temperature and <span class="hlt">ENSO</span>. In particular, the study reveals that a kelvin increase in global mean temperature anomaly can lead to an increase of 30% to even greater than 45% in annual maximum 1-day rainfall, which were observed pronouncedly over central Vietnam, southern coast of Myanmar, northwestern sections of Thailand, northwestern tip of Sumatra, central portions of Malaysia, and the Visayas island in central Philippines. Furthermore, a pronounced <span class="hlt">ENSO</span> influence manifested on the seasonal maximum 1-day rainfall; a northward progression of 10%-15% drier condition over Southeast Asia as the El Niño develops from summer to winter is revealed. It is important therefore, to consider the results obtained here for water resources management as well as for adaptation planning to minimize the potential adverse impact of global warming, particularly on extreme rainfall and its associated flood risk over the region</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1244792-interannual-modulation-subtropical-atlantic-boreal-summer-dust-variability-enso','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1244792-interannual-modulation-subtropical-atlantic-boreal-summer-dust-variability-enso"><span>Interannual Modulation of Subtropical Atlantic Boreal Summer Dust Variability by <span class="hlt">ENSO</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>DeFlorio, Mike; Goodwin, Ian D.; Cayan, Dan</p> <p>2016-01-01</p> <p>Dust variability in the climate system has been studied for several decades, yet there remains an incomplete understanding of the dynamical mechanisms controlling interannual and decadal variations in dust transport. The sparseness of multi-year observational datasets has limited our understanding of the relationship between climate variations and atmospheric dust. We use available observations and a century-length fully coupled Community Earth System Model (CESM) simulation to show that the El Niño- Southern Oscillation (<span class="hlt">ENSO</span>) exerts a control on North African dust transport during boreal summer. In CESM, this relationship is stronger over the dusty tropical North Atlantic than near Barbados, onemore » of the few sites having a multi-decadal observed record. During strong La Niña summers in CESM, a statistically significant increase in lower tropospheric easterly wind is associated with an increase in North African dust transport over the Atlantic. Barbados dust and Pacific SST variability are only weakly correlated in both observations and CESM, suggesting that other processes are controlling the crossbasin variability of dust. We also use our CESM simulation to show that the relationship between downstream North African dust transport and <span class="hlt">ENSO</span> fluctuates on multidecadal timescales and may be modulated by the North Atlantic Oscillation (NAO). Our findings indicate that existing observations of dust over the tropical North Atlantic are not extensive enough to completely describe the variability of dust and dust transport, and demonstrate the importance of global models to supplement and interpret observational records.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pices.int/publications/scientific_reports/Report10/default.aspx','USGSPUBS'); return false;" href="http://www.pices.int/publications/scientific_reports/Report10/default.aspx"><span>Biological effects of the 1997/98 <span class="hlt">ENSO</span> in Cook Inlet, Alaska</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Piatt, John F.; Drew, Gary S.; van Pelt, Thomas I.; Abookire, Alisa A.; Nielsen, April; Shultz, Michael T.; Kitaysky, Alexander S.</p> <p>1999-01-01</p> <p>We have been conducting detailed studies of the biology of seabirds in relation to oceanography and forage fish ecology in lower Cook Inlet, Alaska, since 1995. This fortuitously allowed us to document biological effects of the 1997/98 <span class="hlt">ENSO</span> in this region. Anomalously warm sea surface temperatures (SSTs) were observed in the Gulf of Alaska (GOA) beginning in June of 1997, but not in Cook Inlet until September, 1997. Warm temperature anomalies at the surface and at depth persisted until May of 1998, when temperatures returned to average in the GOA and Cook Inlet. Thus, temperature anomalies occurred outside the core window of productivity (June–August) for forage fish and seabirds in both 1997 and 1998. Abundance or production of phytoplankton, zooplankton, fish, and seabirds in lower Cook Inlet varied among years, and overall appeared to be depressed in 1998. We observed a few biological anomalies that might be attributed to <span class="hlt">ENSO</span> effects: (1) a significant die-off of Common Murres occurred in March–May of 1998, (2) murres and Black-legged Kittiwakes were physiologically stressed during the 1998 breeding season, (3) murres failed to reproduce at one colony in 1998, (4) kittiwake breeding success was lower than usual at colonies in 1998, and (5) phenology of breeding was later in 1998 for both murres and kittiwakes. We presume that seabird die-offs, reduced productivity and delayed phenology were linked to a reduction or delay in food availability, but the mechanism by which anomalously warm water temperatures in winter reduce forage fish availability during the summer breeding season for seabirds is not known.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/15000039','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/15000039"><span>Photothermal Stability of an E-Beam Pre-Crosslinked EVA Encapsulant and Its Performance Degradation on <span class="hlt">a-Si</span> Submodules: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pern, F. J.; Watson, G. L.; Glick, S. H.</p> <p>2001-10-01</p> <p>Presented at the 2001 NCPV Program Review Meeting: Study of photothermal stability of special EVA encapsulant by accelerated exposure testing and analysis of causes of performance degradation on <span class="hlt">a-Si</span> modules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990079379&hterms=pacific+ocean+phytoplankton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpacific%2Bocean%2Bphytoplankton','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990079379&hterms=pacific+ocean+phytoplankton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpacific%2Bocean%2Bphytoplankton"><span>Ocean Thermal and Color Evolution During the 1997/1998 <span class="hlt">ENSO</span> Event</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rienecker, Michele</p> <p>1998-01-01</p> <p>A reduced gravity primitive equation modeling and assimilation system is used to study the evolution of the tropical Pacific during the 1997/1998 <span class="hlt">ENSO</span> cycle. The modeling/assimilation scheme ingests satellite altimeter data and TAO temperature profiles and uses SSM/I satellite derived winds as surface boundary forcing. The four-dimensional structure of the upper ocean circulation structure will be compared against available in situ observations across the Pacific basin. In particular, variability near the Galapagos Islands will be highlighted during the spring of 1998 when phytoplankton concentrations were observed to increase a hundred-fold over a two week period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JPhCS.444a2002M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JPhCS.444a2002M"><span>Dosimetry in radiotherapy using <span class="hlt">a-Si</span> EPIDs: Systems, methods, and applications focusing on 3D patient dose estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCurdy, B. M. C.</p> <p>2013-06-01</p> <p>An overview is provided of the use of amorphous silicon electronic portal imaging devices (EPIDs) for dosimetric purposes in radiation therapy, focusing on 3D patient dose estimation. EPIDs were originally developed to provide on-treatment radiological imaging to assist with patient setup, but there has also been a natural interest in using them as dosimeters since they use the megavoltage therapy beam to form images. The current generation of clinically available EPID technology, amorphous-silicon (<span class="hlt">a-Si</span>) flat panel imagers, possess many characteristics that make them much better suited to dosimetric applications than earlier EPID technologies. Features such as linearity with dose/dose rate, high spatial resolution, realtime capability, minimal optical glare, and digital operation combine with the convenience of a compact, retractable detector system directly mounted on the linear accelerator to provide a system that is well-suited to dosimetric applications. This review will discuss clinically available <span class="hlt">a-Si</span> EPID systems, highlighting dosimetric characteristics and remaining limitations. Methods for using EPIDs in dosimetry applications will be discussed. Dosimetric applications using <span class="hlt">a-Si</span> EPIDs to estimate three-dimensional dose in the patient during treatment will be overviewed. Clinics throughout the world are implementing increasingly complex treatments such as dynamic intensity modulated radiation therapy and volumetric modulated arc therapy, as well as specialized treatment techniques using large doses per fraction and short treatment courses (ie. hypofractionation and stereotactic radiosurgery). These factors drive the continued strong interest in using EPIDs as dosimeters for patient treatment verification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM41A2673G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM41A2673G"><span>Utilizing field-aligned current profiles derived from Swarm to estimate the peak emission height of 630 nm auroral arcs: a comparison of methods and discussion of associated error estimates in the <span class="hlt">ASI</span> data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gillies, D. M.; Knudsen, D. J.; Donovan, E.; Jackel, B. J.; Gillies, R.; Spanswick, E.</p> <p>2017-12-01</p> <p>We compare field-aligned currents (FACs) measured by the Swarm constellation of satellites with the location of red-line (630 nm) auroral arcs observed by all-sky imagers (<span class="hlt">ASIs</span>) to derive a characteristic emission height for the optical emissions. In our 10 events we find that an altitude of 200 km applied to the <span class="hlt">ASI</span> maps gives optimal agreement between the two observations. We also compare the new FAC method against the traditional triangulation method using pairs of all-sky imagers (<span class="hlt">ASIs</span>), and against electron density profiles obtained from the Resolute Bay Incoherent Scatter Radar-Canadian radar (RISR-C), both of which are consistent with a characteristic emission height of 200 km. We also present the spatial error associated with georeferencing REdline Geospace Observatory (REGO) and THEMIS all-sky imagers (<span class="hlt">ASIs</span>) and how it applies to altitude projections of the mapped image. Utilizing this error we validate the estimated altitude of redline aurora using two methods: triangulation between <span class="hlt">ASIs</span> and field-aligned current profiles derived from magnetometers on-board the Swarm satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170010650&hterms=tropospheric+ozone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtropospheric%2Bozone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170010650&hterms=tropospheric+ozone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtropospheric%2Bozone"><span>Tropospheric Column Ozone Response to <span class="hlt">ENSO</span> in GEOS-5 Assimilation of OMI and MLS Ozone Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Olsen, Mark A.; Wargan, Krzysztof; Pawson, Steven</p> <p>2016-01-01</p> <p>We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Nino Southern Oscillation (<span class="hlt">ENSO</span>) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the <span class="hlt">ENSO</span> influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Nino 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Nino 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, <span class="hlt">ENSO</span> related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9- year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Nino influence on tropospheric ozone in the middle latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ThApC.tmp..288L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ThApC.tmp..288L"><span>The dependence on atmospheric resolution of <span class="hlt">ENSO</span> and related East Asian-western North Pacific summer climate variability in a coupled model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Bo; Zhao, Guijie; Huang, Gang; Wang, Pengfei; Yan, Bangliang</p> <p>2017-08-01</p> <p>The authors present results for El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) and East Asian-western North Pacific climate variability simulated in a new version high-resolution coupled model (ICM.V2) developed at the Center for Monsoon System Research of the Institute of Atmospheric Physics (CMSR, IAP), Chinese Academy of Sciences. The analyses are based on the last 100-year output of a 1000-year simulation. Results are compared to an earlier version of the same coupled model (ICM.V1), reanalysis, and observations. The two versions of ICM have similar physics but different atmospheric resolution. The simulated climatological mean states show marked improvement over many regions, especially the tropics in ICM.V2 compared to those in ICM.V1. The common bias in the cold tongue has reduced, and the warm biases along the ocean boundaries have improved as well. With improved simulation of <span class="hlt">ENSO</span>, including its period and strength, the <span class="hlt">ENSO</span>-related western North Pacific summer climate variability becomes more realistic compared to the observations. The simulated East Asian summer monsoon anomalies in the El Niño decaying summer are substantially more realistic in ICM.V2, which might be related to a better simulation of the Indo-Pacific Ocean capacitor (IPOC) effect and Pacific decadal oscillation (PDO).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160006463','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160006463"><span>The <span class="hlt">ENSO</span> Effects on Tropical Clouds and Top-of-Atmosphere Cloud Radiative Effects in CMIP5 Models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Su, Wenying; Wang, Hailan</p> <p>2015-01-01</p> <p>The El Nino-Southern Oscillation (<span class="hlt">ENSO</span>) effects on tropical clouds and top-of-atmosphere (TOA) cloud radiative effects (CREs) in Coupled Model Intercomparison Project Phase5 (CMIP5) models are evaluated using satellite-based observations and International Satellite Cloud Climatology Project satellite simulator output. Climatologically, most CMIP5 models produce considerably less total cloud amount with higher cloud top and notably larger reflectivity than observations in tropical Indo-Pacific (60 degrees East - 200 degrees East; 10 degrees South - 10 degrees North). During <span class="hlt">ENSO</span>, most CMIP5 models considerably underestimate TOA CRE and cloud changes over western tropical Pacific. Over central tropical Pacific, while the multi-model mean resembles observations in TOA CRE and cloud amount anomalies, it notably overestimates cloud top pressure (CTP) decreases; there are also substantial inter-model variations. The relative effects of changes in cloud properties, temperature and humidity on TOA CRE anomalies during <span class="hlt">ENSO</span> in the CMIP5 models are assessed using cloud radiative kernels. The CMIP5 models agree with observations in that their TOA shortwave CRE anomalies are primarily contributed by total cloud amount changes, and their TOA longwave CRE anomalies are mostly contributed by changes in both total cloud amount and CTP. The model biases in TOA CRE anomalies particularly the strong underestimations over western tropical Pacific are, however, mainly explained by model biases in CTP and cloud optical thickness (tau) changes. Despite the distinct model cloud biases particularly in tau regime, the TOA CRE anomalies from cloud amount changes are comparable between the CMIP5 models and observations, because of the strong compensations between model underestimation of TOA CRE anomalies from thin clouds and overestimation from medium and thick clouds.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25182667','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25182667"><span>Sensitivity of an Elekta iView GT <span class="hlt">a-Si</span> EPID model to delivery errors for pre-treatment verification of IMRT fields.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Herwiningsih, Sri; Hanlon, Peta; Fielding, Andrew</p> <p>2014-12-01</p> <p>A Monte Carlo model of an Elekta iViewGT amorphous silicon electronic portal imaging device (<span class="hlt">a-Si</span> EPID) has been validated for pre-treatment verification of clinical IMRT treatment plans. The simulations involved the use of the BEAMnrc and DOSXYZnrc Monte Carlo codes to predict the response of the iViewGT <span class="hlt">a-Si</span> EPID model. The predicted EPID images were compared to the measured images obtained from the experiment. The measured EPID images were obtained by delivering a photon beam from an Elekta Synergy linac to the Elekta iViewGT <span class="hlt">a-Si</span> EPID. The <span class="hlt">a-Si</span> EPID was used with no additional build-up material. Frame averaged EPID images were acquired and processed using in-house software. The agreement between the predicted and measured images was analyzed using the gamma analysis technique with acceptance criteria of 3 %/3 mm. The results show that the predicted EPID images for four clinical IMRT treatment plans have a good agreement with the measured EPID signal. Three prostate IMRT plans were found to have an average gamma pass rate of more than 95.0 % and a spinal IMRT plan has the average gamma pass rate of 94.3 %. During the period of performing this work a routine MLC calibration was performed and one of the IMRT treatments re-measured with the EPID. A change in the gamma pass rate for one field was observed. This was the motivation for a series of experiments to investigate the sensitivity of the method by introducing delivery errors, MLC position and dosimetric overshoot, into the simulated EPID images. The method was found to be sensitive to 1 mm leaf position errors and 10 % overshoot errors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ams.confex.com/ams/93Annual/webprogram/Paper219818.html','USGSPUBS'); return false;" href="https://ams.confex.com/ams/93Annual/webprogram/Paper219818.html"><span>The anomalous circulation associated with the <span class="hlt">ENSO</span>-related west Pacific sea surface temperature gradient</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hoell, Andrew; Funk, Christopher C.</p> <p>2013-01-01</p> <p>The temporal evolution and distribution of Pacific SST as well as the near-surface tropical Pacific zonal wind, tropical divergence and vertical velocity are considerably different during <span class="hlt">ENSO</span> events partitioned according to the strength of the WPG. Modifications to the tropical circulation result in changes to the Indo-west Pacific precipitation and vertically integrated energy budgets and are linked to strong and consistent circulation and precipitation modifications throughout the Northern Hemisphere during winter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ClDy...36.2233P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ClDy...36.2233P"><span>Hydro-climatic variability over the Andes of Colombia associated with <span class="hlt">ENSO</span>: a review of climatic processes and their impact on one of the Earth's most important biodiversity hotspots</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poveda, Germán; Álvarez, Diana M.; Rueda, Óscar A.</p> <p>2011-06-01</p> <p>The hydro-climatic variability of the Colombian Andes associated with El Niño-Southern Oscillation (<span class="hlt">ENSO</span>) is reviewed using records of rainfall, river discharges, soil moisture, and a vegetation index (NDVI) as a surrogate for evapotranspiration. Anomalies in the components of the surface water balance during both phases of <span class="hlt">ENSO</span> are quantified in terms of their sign, timing, and magnitude. During El Niño (La Niña), the region experiences negative (positive) anomalies in rainfall, river discharges (average and extremes), soil moisture, and NDVI. <span class="hlt">ENSO</span>'s effects are phase-locked to the seasonal cycle, being stronger during December-February, and weaker during March-May. Besides, rainfall and river discharges anomalies show that the <span class="hlt">ENSO</span> signal exhibits a westerly wave-like propagation, being stronger (weaker) and earlier (later) over the western (eastern) Andes. Soil moisture anomalies are land-cover type dependant, but overall they are enhanced by <span class="hlt">ENSO</span>, showing very low values during El Niño (mainly during dry seasons), but saturation values during La Niña. A suite of large-scale and regional mechanisms cooperating at the ocean-atmosphere-land system are reviewed to explaining the identified hydro-climatic anomalies. This review contributes to an understanding of the hydro-climatic framework of a region identified as the most critical hotspot for biodiversity on Earth, and constitutes a wake-up call for scientists and policy-makers alike, to take actions and mobilize resources and minds to prevent the further destruction of the region's valuable hydrologic and biodiversity resources and ecosystems. It also sheds lights towards the implementation of strategies and adaptation plans to coping with threats from global environmental change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29715773','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29715773"><span><span class="hlt">ASI</span> aurora search: an attempt of intelligent image processing for circular fisheye lens.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Xi; Gao, Xinbo; Song, Bin; Wang, Nannan; Yang, Dong</p> <p>2018-04-02</p> <p>The circular fisheye lens exhibits an approximately 180° angular field-of-view (FOV), which is much larger than that of an ordinary lens. Thus, images captured with a circular fisheye lens are distributed non-uniformly with spherical deformation. Along with the fast development of deep neural networks for normal images, how to apply it to achieve intelligent image processing for a circular fisheye lens is a new task of significant importance. In this paper, we take the aurora images captured with all-sky-imagers (<span class="hlt">ASI</span>) as a typical example. By analyzing the imaging principle of <span class="hlt">ASI</span> and the magnetic characteristics of the aurora, a deformed region division (DRD) scheme is proposed to replace the region proposals network (RPN) in the advanced mask regional convolutional neural network (Mask R-CNN) framework. Thus, each image can be regarded as a "bag" of deformed regions represented with CNN features. After clustering all CNN features to generate a vocabulary, each deformed region is quantified to its nearest center for indexing. On the stage of an online search, a similarity score is computed by measuring the distances between regions in the query image and all regions in the data set, and the image with the highest value is outputted as the top rank search result. Experimental results show that the proposed method greatly improves the search accuracy and efficiency, demonstrating that it is a valuable attempt of intelligent image processing for circular fisheye lenses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18539527','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18539527"><span>Nurse's perceptions and experiences of using of a mobile-phone-based Advanced Symptom Management System (<span class="hlt">ASy</span>MS) to monitor and manage chemotherapy-related toxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maguire, R; McCann, L; Miller, M; Kearney, N</p> <p>2008-09-01</p> <p>Many people diagnosed with cancer will receive chemotherapy as a core component of their care. Recent changes in the delivery of cancer services mean that patients frequently receive care on an out-patient basis and are therefore often required to manage related side effects at home without direct support from oncology health professionals. The use of information and communications technology may be seen as a means of supporting patients receiving chemotherapy in the home care setting. This mixed methods study, reports on the perceptions of nurses (n=35) who participated in a randomised controlled trial of a mobile phone based, Advanced Symptom Management System (<span class="hlt">ASy</span>MS), in the management of chemotherapy-related toxicity in patients with breast, lung and colorectal cancer. Nurses' perceptions of <span class="hlt">ASy</span>MS were evaluated at the start and the end of the study. Overall, they could see the benefits of <span class="hlt">ASy</span>MS in the remote monitoring of chemotherapy toxicity and its role in facilitating early intervention and subsequent management, demonstrating the potential utility of the system within clinical practice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=324084','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=324084"><span>Impacts of forest to urban land conversion and <span class="hlt">ENSO</span> phase on water quality of a public water supply reservoir</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>We used coupled watershed and reservoir models to evaluate the impacts of deforestation and <span class="hlt">ENSO</span> phase on drinking water quality. Source water total organic carbon (TOC) is especially important due to the potential for production of carcinogenic disinfection byproducts (DBPs). The Environmental Flui...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1326147-impacts-enso-events-cloud-radiative-effects-preindustrial-conditions-changes-cloud-fraction-dependence-interactive-aerosol-emiss