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Sample records for late summer vertical

  1. The use of early summer mosquito surveillance to predict late summer West Nile virus activity

    USGS Publications Warehouse

    Ginsberg, Howard S.; Rochlin, Ilia; Campbell, Scott R.

    2010-01-01

    Utility of early-season mosquito surveillance to predict West Nile virus activity in late summer was assessed in Suffolk County, NY. Dry ice-baited CDC miniature light traps paired with gravid traps were set weekly. Maximum-likelihood estimates of WNV positivity, minimum infection rates, and % positive pools were generally well correlated. However, positivity in gravid traps was not correlated with positivity in CDC light traps. The best early-season predictors of WNV activity in late summer (estimated using maximum-likelihood estimates of Culex positivity in August and September) were early date of first positive pool, low numbers of mosquitoes in July, and low numbers of mosquito species in July. These results suggest that early-season entomological samples can be used to predict WNV activity later in the summer, when most human cases are acquired. Additional research is needed to establish which surveillance variables are most predictive and to characterize the reliability of the predictions.

  2. Global Views of Mars in late Northern Summer

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Mars Global Surveyor (MGS) orbits around the red planet 12 times a day. Each orbit goes from pole to pole. Over the course of a single day, the wide angle cameras of the Mars Orbiter Camera (MOC) system take 24 pictures--12 red and 12 blue--that are assembled to create a daily global map. Such global views are used to monitor the martian weather and observe changes in the patterns of frost and dust distribution on the surface. These two pictures are examples of what Mars looks like in late northern summer, which is also late southern winter. At this time of year, the south polar cap (bottom, white feature in each image) is very large, extending from the south pole northward to 60oS. Also at this time of year, clouds of water ice crystals are common over the four largest volcanoes in Tharsis. The picture on the right shows Tharsis, with the four volcanoes forming a triangle resembling the pattern of holes on a bowling ball. The image on the left is centered on Syrtis Major, a dark, windswept volcanic plain so large that it has been known to science since the first telescopes were turned toward Mars in the 1600s. The elliptical bright feature at lower-center in the left image is the Hellas Basin, the largest unequivocal impact basin (formed by an asteroid or comet) on the planet. Hellas is approximately 2200 km (1,370 mi) across.

  3. How can anomalous western North Pacific Subtropical High intensify in late summer?

    NASA Astrophysics Data System (ADS)

    Xiang, Baoqiang; Wang, Bin; Yu, Weidong; Xu, Shibin

    2013-05-01

    The western North Pacific (WNP) Subtropical High (WNPSH) is a controlling system for East Asian Summer monsoon and tropical storm activities, whereas what maintains the anomalous summertime WNPSH has been a long-standing riddle. Here we demonstrate that the local convection-wind-evaporation-SST (CWES) feedback relying on both mean flows and mean precipitation is key in maintaining the WNPSH, while the remote forcing from the development of the El Niño/Southern Oscillation is secondary. Strikingly, the majority of strong WNPSH cases exhibit anomalous intensification in late summer (August), which is dominantly determined by the seasonal march of the mean state. That is, enhanced mean precipitation associated with strong WNP monsoon trough in late summer makes atmospheric response much more sensitive to local SST forcing than early summer.

  4. Contribution of the phase transition of Pacific Decadal Oscillation to the late 1990s' shift in East China summer rainfall

    NASA Astrophysics Data System (ADS)

    zhu, yali

    2016-04-01

    Based on our previous study, the interdecadal changes in summer rainfall over East China in the late 1990s are further explored here. The increased local rising motion is implicated as the dominant factor of increased rainfall in the lower Huang-Huai River valley (LHR). Both the observation and numerical experiments using Community Atmosphere Model, version 4 suggest that the negative Pacific Decadal Oscillation (PDO) mode can result in rising anomalies and thus more rainfall in the LHR. The East Asian westerly jet stream (EAWJS) is suggested as a bridge to link the Pacific sea surface temperature anomalies and East Asian summer rainfall. Model results reveal that the negative PDO mode can lead to significant easterly anomalies over East Asia. As a result, the EAWJS is weakened and shifts poleward, which coincides with observed changes in EAWJS after the late 1990s. In addition, weakened and poleward shifted EAWJS can result in an anomalous ascending motion to its south (in the LHR) by modulating the jet-related secondary meridional-vertical circulation. Consequently, rainfall increased in the LHR after the late 1990s. Besides, the positive Atlantic Meridional Oscillation can only induce insignificant changes over East Asia and partly counteract the negative PDO effect there.

  5. Southern European rainfall reshapes the early-summer circumglobal teleconnection after the late 1970s

    NASA Astrophysics Data System (ADS)

    Lin, Zhongda; Liu, Fei; Wang, Bin; Lu, Riyu; Qu, Xia

    2016-08-01

    The summer circumglobal teleconnection (CGT), which crucially affects mid-latitude climate in the Northern Hemisphere, is generally characterized by a mid-latitude wave train along the strong upper-tropospheric westerly jet. In this study a significant change is identified in the spatial pattern of the early-summer CGT after the late 1970s: An additional high-latitude wave train has occurred over northern Eurasia. Based on observational evidences and simulation results with a linear baroclinic model, it is proposed that the post-1970s CGT change is induced by enhanced impact of rainfall over southern Europe (SE) after the late 1970s. Specifically, the mid-latitude wave train of CGT in early summer is dominated by Indian rainfall before the late 1970s but by both rainfall over India and SE after the late 1970s; the high-latitude wave train of CGT occurring after the late 1970s, however, is induced only by the SE rainfall. The coupled Indian and SE rainfall after the late 1970s, which is probably due to the basic flow change over the North Atlantic, induce both mid-latitude and high-latitude wave trains of the CGT.

  6. Hydroclimatic controls on late-summer low flow in British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Stahl, K.; Moore, R. D.; Allen, D. M.; Whitfield, P. H.

    2009-05-01

    For catchments in the Pacific Northwest of North America the summer period is typically dominated by low flows associated with the relatively warm, dry summers in that region. In recent years streamflow during this period has been critical in terms of water use and fisheries, and there is increasing concern regarding how future climate change with potentially more severe summer droughts may affect late-summer flows. In addition, it is feared that earlier snowmelt timing in spring causes longer recession periods and consequently lower streamflow during summer. This study examined the sensitivity of late summer flows of 153 unregulated rivers over the period 1976-2003 to hydroclimatic influences by fitting regression models using simultaneous and lagged variables of precipitation and timing and magnitude of the snowmelt. To assess potential additional influences of long-term storage changes the residuals were tested for trends and serial correlation. A decrease in September flows across most of the region is broadly consistent with a decline in September precipitation. The most important control on August flows for all streamflow regimes is August precipitation. Lagged variables including July precipitation and the previous winter's precipitation are also positively but more weakly related to August streamflow. Rain-dominated and hybrid catchments tended to have positive trends in their residuals in August, suggesting an increasing trend in groundwater storage. Snow-melt dominated catchments showed no tendency to trends but the runs test detected a substantial number of stations with non-random residuals. This regional study greatly improves the understanding of the hydroclimatic influences on extreme summer low flow in the region. Results suggest that (the less predictable) summer climate is a larger influence than previously assumed. They also help to identify where seasonal snow processes or long- term groundwater storage should be considered in model development

  7. Vertical variations in the influence of the amount effect: South American Summer Monsoon Region

    NASA Astrophysics Data System (ADS)

    Samuels-Crow, K. E.; Galewsky, J.; Worden, J. R.

    2014-12-01

    Recent theoretical studies have shown that convective recycling of atmospheric water vapor gives rise to the isotope "amount effect" in which d values are lower than predicted by simple Rayleigh distillation processes (i.e. (DdD = dDvapor ­- dDRayleigh < 0‰). Several studies have linked isotopes in precipitation [e.g. Vimeux et al., 2009] and atmospheric water vapor [e.g. Samuels-Crow et al., 2014] in the tropical Andes to upwind convection associated with the South American Summer Monsoon (SASM). The vertical structure of this convective influence, however, remains unknown. Understanding the vertical structure of the amount effect over South America is essential for improving theoretical constraints and developing better models of the influence of the SASM on southern hemisphere humidity. Additionally, evaluating the vertical and lateral extent of the SASM's convective influence can provide important constraints for interpreting paleoclimate proxies in the region. We use data from the Tropospheric Emission Spectrometer (TES) to examine the vertical structure of the amount effect associated with the SASM and relate these results to regional convective precipitation and local subcloud equivalent potential temperature. Preliminary results show that DdD is below 0‰ from the boundary layer through the mid-troposphere over tropical South America during austral summer, and meridional averages show that convective precipitation is highest over these areas where DdD < 0‰ extends higher in the atmosphere. We hypothesize that the depth of convection in the monsoon region controls the vertical structure of DdD, which should also be coherently linked to local equivalent potential temperature. References Vimeux et al. (2009), Palaeogeogr Palaeocl, 281(3-4), 229-241, doi:10.1016/j.palaeo.2008.03.054. Samuels-Crow et al. (2014), J Geophys Res-Atmos, doi:10.1002/(ISSN)2169-8996.

  8. Influences of ENSO on the vertical coupling of atmospheric circulation during the onset of South Asian summer monsoon

    NASA Astrophysics Data System (ADS)

    Liu, Boqi; Wu, Guoxiong; Ren, Roncai

    2015-10-01

    Based on multiple sources of atmospheric and oceanic data, this study performs a series of composite analysis of the South Asian summer monsoon (SASM) onset against ENSO events, and indicates that warm/cold ENSO events induce later/earlier onset of the SASM by modulating the vertical coupling of the upper- and lower-level circulation over the South Asia. Specifically, during the monsoon onset of Bay of Bengal (BOB), the ENSO-induced convection anomalies over the southern Philippines can modulate the position of South Asian high (SAH) in late April in the upper troposphere, which evolves to affect the monsoon onset convection by changing the upper divergence-pumping effect. In the lower troposphere, ENSO induces an anomalous zonal gradient of sea surface temperature (SST) over the Indian-western Pacific Ocean to alter the barotropic instability which further affects the formation of BOB monsoon onset convection. During the Indian summer monsoon onset, the anomalous convection over northeastern BOB and Indochina Peninsula in late May act to change the SAH position and its relevant upper divergence-pumping over the Arabian Sea (AS). Meanwhile, the Indian monsoon onset convection is also modulated by the ENSO-induced changes in intensity of the inertial instability and the forced convection over the AS, which are related to an ENSO-induced anomalous cross-equatorial SST gradient and zonally asymmetric meridional gradient of sea level pressure, and an anomalous westerly over the central AS in the lower troposphere. Results demonstrate that during the BOB and India monsoon onset, the influences of ENSO on the upper circulation are similar, but are distinctly different on the lower-level circulation.

  9. Factors determining the vertical profile of dimethylsulfide in the Sargasso Sea during summer

    NASA Astrophysics Data System (ADS)

    Gabric, A. J.; Matrai, P. A.; Kiene, R. P.; Cropp, R.; Dacey, J. W. H.; DiTullio, G. R.; Najjar, R. G.; Simó, R.; Toole, D. A.; delValle, D. A.; Slezak, D.

    2008-05-01

    The major source of reduced sulfur in the remote marine atmosphere is the biogenic compound dimethylsulfide (DMS), which is ubiquitous in the world's oceans and released through food web interactions. Relevant fluxes and concentrations of DMS, its phytoplankton-produced precursor, dimethylsulfoniopropionate (DMSP) and related parameters were measured during an intensive Lagrangian field study in two mesoscale eddies in the Sargasso Sea during July-August 2004, a period characterized by high mixed-layer DMS and low chlorophyll—the so-called 'DMS summer paradox'. We used a 1-D vertically variable DMS production model forced with output from a 1-D vertical mixing model to evaluate the extent to which the simulated vertical structure in DMS and DMSP was consistent with changes expected from field-determined rate measurements of individual processes, such as photolysis, microbial DMS and dissolved DMSP turnover, and air-sea gas exchange. Model numerical experiments and related parametric sensitivity analyses suggested that the vertical structure of the DMS profile in the upper 60 m was determined mainly by the interplay of the two depth-variable processes—vertical mixing and photolysis—and less by biological consumption of DMS. A key finding from the model calibration was the need to increase the DMS(P) algal exudation rate constant, which includes the effects of cell rupture due to grazing and cell lysis, to significantly higher values than previously used in other regions. This was consistent with the small algal cell size and therefore high surface area-to-volume ratio of the dominant DMSP-producing group—the picoeukaryotes.

  10. Analysis of extreme summers and prior late winter/spring conditions in central Europe

    NASA Astrophysics Data System (ADS)

    Träger-Chatterjee, C.; Müller, R. W.; Bendix, J.

    2013-05-01

    Drought and heat waves during summer in mid-latitudes are a serious threat to human health and agriculture and have negative impacts on the infrastructure, such as problems in energy supply. The appearance of such extreme events is expected to increase with the progress of global warming. A better understanding of the development of extremely hot and dry summers and the identification of possible precursors could help improve existing seasonal forecasts in this regard, and could possibly lead to the development of early warning methods. The development of extremely hot and dry summer seasons in central Europe is attributed to a combined effect of the dominance of anticyclonic weather regimes and soil moisture-atmosphere interactions. The atmospheric circulation largely determines the amount of solar irradiation and the amount of precipitation in an area. These two variables are themselves major factors controlling the soil moisture. Thus, solar irradiation and precipitation are used as proxies to analyse extreme sunny and dry late winter/spring and summer seasons for the period 1958-2011 in Germany and adjacent areas. For this purpose, solar irradiation data from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis dataset, as well as remote sensing data are used. Precipitation data are taken from the Global Precipitation Climatology Project. To analyse the atmospheric circulation geopotential data at 850 hPa are also taken from the European Center for Medium Range Weather Forecast 40-yr and interim re-analysis datasets. For the years in which extreme summers in terms of high solar irradiation and low precipitation are identified, the previous late winter/spring conditions of solar irradiation and precipitation in Germany and adjacent areas are analysed. Results show that if the El Niño-Southern Oscillation (ENSO) is not very intensely developed, extremely high solar irradiation amounts, together with extremely low precipitation

  11. The effect of vertical and horizontal symmetry on memory for tactile patterns in late blind individuals.

    PubMed

    Cattaneo, Zaira; Vecchi, Tomaso; Fantino, Micaela; Herbert, Andrew M; Merabet, Lotfi B

    2013-02-01

    Visual stimuli that exhibit vertical symmetry are easier to remember than stimuli symmetric along other axes, an advantage that extends to the haptic modality as well. Critically, the vertical symmetry memory advantage has not been found in early blind individuals, despite their overall superior memory, as compared with sighted individuals, and the presence of an overall advantage for identifying symmetric over asymmetric patterns. The absence of the vertical axis memory advantage in the early blind may depend on their total lack of visual experience or on the effect of prolonged visual deprivation. To disentangle this issue, in this study, we measured the ability of late blind individuals to remember tactile spatial patterns that were either vertically or horizontally symmetric or asymmetric. Late blind participants showed better memory performance for symmetric patterns. An additional advantage for the vertical axis of symmetry over the horizontal one was reported, but only for patterns presented in the frontal plane. In the horizontal plane, no difference was observed between vertical and horizontal symmetric patterns, due to the latter being recalled particularly well. These results are discussed in terms of the influence of the spatial reference frame adopted during exploration. Overall, our data suggest that prior visual experience is sufficient to drive the vertical symmetry memory advantage, at least when an external reference frame based on geocentric cues (i.e., gravity) is adopted. PMID:23150215

  12. Temporal variation and stoichiometric ratios of organic matter remineralization in bottom waters of the northern Gulf of Mexico during late spring and summer

    NASA Astrophysics Data System (ADS)

    Xue, Jianhong; Cai, Wei-Jun; Hu, Xinping; Huang, Wei-Jen; Lohrenz, Steven E.; Gundersen, Kjell

    2015-12-01

    An improved extended optimum multiparameter (eOMP) analysis was applied to hydrographic (temperature and salinity), and water chemistry data, including dissolved oxygen (O2), nutrients (nitrate plus nitrite, phosphate, and silicate), dissolved inorganic carbon (DIC), and total alkalinity (TAlk) data collected during late spring and summer from 2006 to 2012 in bottom waters off the Louisiana coast, to explore the dynamics and stoichiometry of DIC production during the development and maintenance of summer hypoxia. Our analysis demonstrated that DIC in bottom water was relatively low from April to June, but increased significantly in July, peaked in August, and dropped slightly in September. Furthermore, DIC production resulted from both aerobic organic carbon (OC) respiration and denitrification, as well as substantial loss due to vertical mixing with surface water. The average summer gross OC respiration rate was estimated to be 0.19 g C m-2 d-1, with the highest values occurring in late summer when hypoxic conditions dominated. We also found that Corg/N/P/-O2 remineralization ratios for aerobic respiration were generally consistent with the classic Redfield ratio (106/16/1/138) except individual C/N and C/P ratios were slightly lower, indicating that marine OC was the major source of the DIC production in the bottom water. This study quantified the role of temporal bottom-water microbial respiration to seasonal DIC dynamics and provided a means for studying the stoichiometry of biogeochemical processes in coastal waters.

  13. Vertical profiling of aerosol particles and trace gases over the central Arctic Ocean during summer

    NASA Astrophysics Data System (ADS)

    Kupiszewski, P.; Leck, C.; Tjernström, M.; Sjogren, S.; Sedlar, J.; Graus, M.; Müller, M.; Brooks, B.; Swietlicki, E.; Norris, S.; Hansel, A.

    2013-12-01

    Unique measurements of vertical size-resolved aerosol particle concentrations, trace gas concentrations and meteorological data were obtained during the Arctic Summer Cloud Ocean Study (ASCOS, www.ascos.se), an International Polar Year project aimed at establishing the processes responsible for formation and evolution of low-level clouds over the high Arctic summer pack ice. The experiment was conducted from on board the Swedish icebreaker Oden, and provided both ship- and helicopter-based measurements. This study focuses on the vertical helicopter profiles and onboard measurements obtained during a three-week period when Oden was anchored to a drifting ice floe, and sheds light on the characteristics of Arctic aerosol particles and their distribution throughout the lower atmosphere. Distinct differences in aerosol particle characteristics within defined atmospheric layers are identified. Within the lowermost couple hundred metres, transport from the marginal ice zone (MIZ), condensational growth and cloud processing develop the aerosol population. During two of the four representative periods defined in this study, such influence is shown. At altitudes above about 1 km, long-range transport occurs frequently. However, only infrequently does large-scale subsidence descend such air masses to become entrained into the mixed layer in the high Arctic, and therefore long-range transport plumes are unlikely to directly influence low-level stratiform cloud formation. Nonetheless, such plumes can influence the radiative balance of the planetary boundary layer (PBL) by influencing formation and evolution of higher clouds, as well as through precipitation transport of particles downwards. New particle formation was occasionally observed, particularly in the near-surface layer. We hypothesize that the origin of these ultrafine particles could be in biological processes, both primary and secondary, within the open leads between

  14. Vertical profiling of aerosol particles and trace gases over the central Arctic Ocean during summer

    NASA Astrophysics Data System (ADS)

    Kupiszewski, P.; Leck, C.; Tjernström, M.; Sjogren, S.; Sedlar, J.; Graus, M.; Müller, M.; Brooks, B.; Swietlicki, E.; Norris, S.; Hansel, A.

    2013-04-01

    Unique measurements of vertical size resolved aerosol particle concentrations, trace gas concentrations and meteorological data were obtained during the Arctic Summer Cloud Ocean Study (ASCOS, http://www.ascos.se), an International Polar Year project aimed at establishing the processes responsible for formation and evolution of low-level clouds over the high Arctic summer pack ice. The experiment was conducted from onboard the Swedish icebreaker Oden, and provided both ship- and helicopter-based measurements. This study focuses on the vertical helicopter profiles and onboard measurements obtained during a three-week period when Oden was anchored to a drifting ice floe, and sheds light on the characteristics of Arctic aerosol particles and their distribution throughout the lower atmosphere. Distinct differences in aerosol particle characteristics within defined atmospheric layers are identified. Near the surface (lowermost couple hundred meters), transport from the marginal ice zone (MIZ), if sufficiently short (less than ca. 2 days), condensational growth and cloud-processing develop the aerosol population. During two of the four representative periods defined in this study, such influence is shown. At altitudes above about 1 km, long-range transport occurs frequently. However, only infrequently does large-scale subsidence descend such air masses to become entrained into the mixed layer in the high Arctic, and therefore they are unlikely to directly influence low-level stratiform cloud formation. Nonetheless, long-range transport plumes can influence the radiative balance of the PBL by influencing formation and evolution of higher clouds, as well as through precipitation transport of particles downwards. New particle formation was occasionally observed, particularly in the near-surface layer. We hypothesize that the origin of these ultrafine particles can be from biological processes, both primary and secondary

  15. Evidence for ice-free summers in the late Miocene central Arctic Ocean.

    PubMed

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-01-01

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate. PMID:27041737

  16. Evidence for ice-free summers in the late Miocene central Arctic Ocean

    PubMed Central

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-01-01

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate. PMID:27041737

  17. Evidence for ice-free summers in the late Miocene central Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Niessen, Frank; Forwick, Matthias; Gebhardt, Catalina; Jensen, Laura; Kaminski, Michael; Kopf, Achim; Matthiessen, Jens; Jokat, Wilfried; Lohmann, Gerrit

    2016-04-01

    Although the permanently to seasonally ice-covered Arctic Ocean is a unique and sensitive component in the Earth's climate system, the knowledge of its long-term climate history remains very limited due to the restricted number of pre-Quaternary sedimentary records. During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides along Lomonosov Ridge. Removal of younger sediments from steep headwalls has led to exhumation of Miocene sediments close to the seafloor. Here we document the presence of IP25 as a proxy for spring sea-ice cover and alkenone-based summer sea-surface temperatures >4 °C that support a seasonal sea-ice cover with an ice-free summer season being predominant during the late Miocene in the central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or a weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate.

  18. Impact of Sea Surface Temperature Trend on Late Summer Asian Rainfall in the 20th century

    NASA Astrophysics Data System (ADS)

    Bian, Qiying; Lu, Riyu

    2013-04-01

    The impact of the global sea surface temperature (SST) warming trend, which is the leading mode of SST variability, on late summer Asian rainfall is analyzed based on the simulations of five atmospheric general circulation models (AGCMs), which are performed by the U. S. Climate Variability and Predictability (CLIVAR) Drought Working Group. Our evaluations of the model outputs indicate that these models roughly capture the main features of climatological rainfall and circulations over Asia and the western North Pacific (WNP), but they simulate a too strong monsoon trough and a too northward shifted in the subtropical anticyclone in the WNP, and fail to reproduce the rainy belt over East Asia. It is found that all of the models simulate an intensified WNP subtropical high (WNPSH) in late summer, and an enhanced precipitation in the tropical Indian Ocean and the maritime continent, and a suppressed precipitation in the tropical WNP, when the models are forced with the SST trend, which is characterized by a significant increase in the Indian Ocean and western Pacific. All these changes are suggested to be dynamically coherent. In addition, precipitation changes forced by the SST trend are similar in the tropics, but show an apparent difference over extratropical Asia, in comparison with the observed rainfall trend. The possible reasons for this similarity and difference are discussed.

  19. Late Holocene Asian summer monsoon dynamics from small but complex networks of paleoclimate data

    NASA Astrophysics Data System (ADS)

    Rehfeld, Kira; Marwan, Norbert; Breitenbach, Sebastian F. M.; Kurths, Jürgen

    2013-07-01

    Internal variability of the Asian monsoon system and the relationship amongst its sub-systems, the Indian and East Asian Summer Monsoon, are not sufficiently understood to predict its responses to a future warming climate. Past environmental variability is recorded in Palaeoclimate proxy data. In the Asian monsoon domain many records are available, e.g. from stalagmites, tree-rings or sediment cores. They have to be interpreted in the context of each other, but visual comparison is insufficient. Heterogeneous growth rates lead to uneven temporal sampling. Therefore, computing correlation values is difficult because standard methods require co-eval observation times, and sampling-dependent bias effects may occur. Climate networks are tools to extract system dynamics from observed time series, and to investigate Earth system dynamics in a spatio-temporal context. We establish paleoclimate networks to compare paleoclimate records within a spatially extended domain. Our approach is based on adapted linear and nonlinear association measures that are more efficient than interpolation-based measures in the presence of inter-sampling time variability. Based on this new method we investigate Asian Summer Monsoon dynamics for the late Holocene, focusing on the Medieval Warm Period (MWP), the Little Ice Age (LIA), and the recent period of warming in East Asia. We find a strong Indian Summer Monsoon (ISM) influence on the East Asian Summer Monsoon during the MWP. During the cold LIA, the ISM circulation was weaker and did not extend as far east. The most recent period of warming yields network results that could indicate a currently ongoing transition phase towards a stronger ISM penetration into China. We find that we could not have come to these conclusions using visual comparison of the data and conclude that paleoclimate networks have great potential to study the variability of climate subsystems in space and time.

  20. Black-footed ferret areas of activity during late summer and fall at Meeteetse, Wyoming

    USGS Publications Warehouse

    Fagerstone, K.A.; Biggins, D.E.

    2011-01-01

    Radiotelemetry was used during 1983 and 1984 to collect information on short-term areas of activity for black-footed ferrets (Mustela nigripes) near Meeteetse, Wyoming. This population ultimately provided ferrets for the captive-breeding program that bred and released offspring into the wild since 1991. We fitted 5 adult ferrets and 13 juveniles with radiotransmitters and followed their movements during late summer and fall. Adult males had 7-day areas of activity that were >6 times as large as those of adult females. Activity areas of adult males varied little in coverage or location on a weekly basis, but females sequentially shifted their areas. Unlike juvenile females, juvenile males tended to leave their natal colonies. ?? 2011 American Society of Mammalogists.

  1. Late Summer Ozone Variability in the Lower Troposphere of the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Tsamalis, Christoforos; Papayannis, Alexandros; Ancellet, Gerard; Ravetta, François

    2016-06-01

    During the STAAARTE 96 Hellen aircraft campaign the lidar ALTO together with in situ measurements examined the ozone and aerosols variability in the lower troposphere over the Eastern Mediterranean region. Ozone mean value in the free troposphere (FT) measured from ALTO was 48 ppb, while it was 45 ppb from in situ observations; the aerosols mean scattering coefficient (550 nm) was 31 Mm-1. The FT ozone distributions of the two instruments are significantly different to distinct sampling. Air masses origin examination using the FLEXPART model for low and high FT ozone observations during late summer indicate that low ozone masses come from Mediterranean/North Africa regions travelling at low altitude, while high ozone masses emanate from Europe's middle or upper troposphere.

  2. The vertical structure of cloud radiative heating over the Indian subcontinent during summer monsoon

    NASA Astrophysics Data System (ADS)

    Johansson, E.; Devasthale, A.; L'Ecuyer, T.; Ekman, A. M. L.; Tjernström, M.

    2015-10-01

    Clouds forming during the summer monsoon over the Indian subcontinent affect its evolution through their radiative impact as well as the release of latent heat. While the latter is previously studied to some extent, comparatively little is known about the radiative impact of different cloud types and the vertical structure of their radiative heating/cooling effects. Therefore, the main aim of this study is to partly fill this knowledge gap by investigating and documenting the vertical distributions of the different cloud types associated with the Indian monsoon and their radiative heating/cooling using the active radar and lidar sensors onboard CloudSat and CALIPSO. The intraseasonal evolution of clouds from May to October is also investigated to understand pre-to-post monsoon transitioning of their radiative heating/cooling effects. The vertical structure of cloud radiative heating (CRH) follows the northward migration and retreat of the monsoon from May to October. Throughout this time period, stratiform clouds radiatively warm the middle troposphere and cool the upper troposphere by more than ±0.2 K day-1 (after weighing by cloud fraction), with the largest impacts observed in June, July and August. During these months, the fraction of high thin cloud remains high in the tropical tropopause layer (TTL). Deep convective towers cause considerable radiative warming in the middle and upper troposphere, but strongly cool the base and inside of the TTL. This cooling is stronger during active (-1.23 K day-1) monsoon periods compared to break periods (-0.36 K day-1). The contrasting radiative warming effect of high clouds in the TTL is twice as large during active periods than in break periods. These results highlight the increasing importance of CRH with altitude, especially in the TTL. Stratiform (made up of alto- and nimbostratus clouds) and deep convection clouds radiatively cool the surface by approximately -100 and -400 W m-2 respectively while warming the

  3. Modeling Late-Summer Distribution of Golden Eagles (Aquila chrysaetos) in the Western United States.

    PubMed

    Nielson, Ryan M; Murphy, Robert K; Millsap, Brian A; Howe, William H; Gardner, Grant

    2016-01-01

    Increasing development across the western United States (USA) elevates concerns about effects on wildlife resources; the golden eagle (Aquila chrysaetos) is of special concern in this regard. Knowledge of golden eagle abundance and distribution across the western USA must be improved to help identify and conserve areas of major importance to the species. We used distance sampling and visual mark-recapture procedures to estimate golden eagle abundance from aerial line-transect surveys conducted across four Bird Conservation Regions in the western USA between 15 August and 15 September in 2006-2010, 2012, and 2013. To assess golden eagle-habitat relationships at this scale, we modeled counts of golden eagles seen during surveys in 2006-2010, adjusted for probability of detection, and used land cover and other environmental factors as predictor variables within 20-km2 sampling units randomly selected from survey transects. We found evidence of positive relationships between intensity of use by golden eagles and elevation, solar radiation, and mean wind speed, and of negative relationships with the proportion of landscape classified as forest or as developed. The model accurately predicted habitat use observed during surveys conducted in 2012 and 2013. We used the model to construct a map predicting intensity of use by golden eagles during late summer across our ~2 million-km2 study area. The map can be used to help prioritize landscapes for conservation efforts, identify areas where mitigation efforts may be most effective, and identify regions for additional research and monitoring. In addition, our map can be used to develop region-specific (e.g., state-level) density estimates based on the latest information on golden eagle abundance from a late-summer survey and aid designation of geographic management units for the species. PMID:27556735

  4. Modeling Late-Summer Distribution of Golden Eagles (Aquila chrysaetos) in the Western United States

    PubMed Central

    Gardner, Grant

    2016-01-01

    Increasing development across the western United States (USA) elevates concerns about effects on wildlife resources; the golden eagle (Aquila chrysaetos) is of special concern in this regard. Knowledge of golden eagle abundance and distribution across the western USA must be improved to help identify and conserve areas of major importance to the species. We used distance sampling and visual mark-recapture procedures to estimate golden eagle abundance from aerial line-transect surveys conducted across four Bird Conservation Regions in the western USA between 15 August and 15 September in 2006–2010, 2012, and 2013. To assess golden eagle-habitat relationships at this scale, we modeled counts of golden eagles seen during surveys in 2006–2010, adjusted for probability of detection, and used land cover and other environmental factors as predictor variables within 20-km2 sampling units randomly selected from survey transects. We found evidence of positive relationships between intensity of use by golden eagles and elevation, solar radiation, and mean wind speed, and of negative relationships with the proportion of landscape classified as forest or as developed. The model accurately predicted habitat use observed during surveys conducted in 2012 and 2013. We used the model to construct a map predicting intensity of use by golden eagles during late summer across our ~2 million-km2 study area. The map can be used to help prioritize landscapes for conservation efforts, identify areas where mitigation efforts may be most effective, and identify regions for additional research and monitoring. In addition, our map can be used to develop region-specific (e.g., state-level) density estimates based on the latest information on golden eagle abundance from a late-summer survey and aid designation of geographic management units for the species. PMID:27556735

  5. Impact of sea surface temperature trend on late summer Asian rainfall in the twentieth century

    NASA Astrophysics Data System (ADS)

    Bian, Qiying; Lu, Riyu

    2013-05-01

    impact of the global sea surface temperature (SST) warming trend, which is the leading mode of SST variability, on late summer Asian rainfall is analyzed based on the simulations of five atmospheric general circulation models, which are performed by the U. S. Climate Variability and Predictability Drought Working Group. Our evaluations of the model outputs indicate that these models roughly capture the main features of climatological rainfall and circulations over Asia and the western North Pacific (WNP), but they simulate a too strong monsoon trough and a too northward shifted in the subtropical anticyclone in the WNP and fail to reproduce the rain belt over East Asia. It is found that all of the models simulate an intensified WNP subtropical high (WNPSH) in late summer, an enhanced precipitation in the tropical Indian Ocean and the maritime continent, and a suppressed precipitation in the South Asian monsoon region, the South China Sea, and the Philippine Sea, when the models are forced with the SST trend, which is characterized by a significant increase in the Indian Ocean and western Pacific. All these changes are suggested to be dynamically coherent. The warmer SST trend in the Indian Ocean and western Pacific may suppress precipitation over the Philippine Sea and thus result in a lower tropospheric anticyclonic circulation over the subtropical WNP. The warmer SSTs in the Indian Ocean may also be responsible for the anomalous easterlies and resultant less rainfall over the South Asian monsoon region. The precipitation changes forced by the SST trend are similar in the maritime continent but show an apparent difference over East Asia, in comparison with the observed rainfall trend over lands. The possible reasons for this difference are discussed.

  6. Late Holocene Indian summer monsoon variations recorded at Lake Erhai, Southwestern China

    NASA Astrophysics Data System (ADS)

    Xu, Hai; Zhou, Xinying; Lan, Jianghu; Liu, Bin; Sheng, Enguo; Yu, Keke; Cheng, Peng; Wu, Feng; Hong, Bin; Yeager, Kevin M.; Xu, Sheng

    2015-03-01

    In this study we report changes in Indian summer monsoon (ISM) intensity during the past ~ 3500 yr inferred from proxy indices at Lake Erhai, southwestern China. Both the pollen concentrations and other proxy indices, including sediment grain size, total organic carbon contents (TOC), and elemental contents (e.g., Fe, Al), clearly indicate a long term decreasing trend in ISM intensity over the late Holocene. During the period from approximately AD 750 to AD 1200, pollen concentrations of conifer and broadleaf trees, and herbs reached the lowest levels over the past ~ 3500 yr; while the pollen percentages of both herbs and broadleaf trees increased, suggesting a significant medieval drought. The grain size, TOC, and elemental contents also support an arid climate during the medieval period. The Little Ice Age (LIA) at Lake Erhai was characterized as cold and wet. The medieval and LIA climatic patterns at Lake Erhai were similar to those over most of the ISM areas, but anti-phase with those over East Asian summer monsoon (EASM) areas. We suspect that sea surface temperature variations in the Indo-Pacific oceans and the related land-sea thermal contrasts may be responsible for such hydroclimatic differences between EASM and ISM areas.

  7. Dynamic Earth Models: Sea Level and Vertical Motion of Continents since the Late Cretaceous

    NASA Astrophysics Data System (ADS)

    Spasojevic, S.; Gurnis, M.

    2010-12-01

    We show results from global dynamic earth models (DEMs) since the Late Cretaceous, which combine inverse and forward models of mantle convection, with viscosity that varies vertically and laterally. DEMs assimilate plate tectonic reconstructions, and account for the influence of the geoid and the evolving paleogeography of the sea floor self-consistently. Global DEMs are computed in the mantle frame, but we implement the integrated plate reconstruction-mantle convection system that enables linkage between geologic observations obtained in a plate frame of reference and dynamic topography, which is essential for sea-level studies. Since DEMs account for the most important factors controlling long-term sea-level change self-consistently, we present implications for the influence of the mantle on vertical motion of earth’s surface and regional and global sea-level change since Late Cretaceous. We find that neither dynamic topography nor eustasy dominant the global patterns of marine sedimentation on continents since the Late Cretaceous. Dynamic topography appears to be important in controlling the flooding patterns in North America, Australia and southern India since the Late Cretaceous, Sundaland since the Oligocene, and Arabia during Cenozoic. Eustasy has a larger role in controlling flooding in Eurasia and northern India. Mantle dynamics also seems to be an important factor contributing to Cenozoic long-wavelength tilting in Australia and Siberia. Interpretation of modeling results and the relative importance of eustatic versus dynamic factors is difficult in Africa and South America due to either unknown paleotopography or limited stratigraphic data.

  8. Bowhead whale acoustic activity in the southeast Beaufort Sea during late summer 2008-2010.

    PubMed

    Charif, Russell A; Rahaman, Ashakur; Muirhead, Charles A; Pitzrick, Michael S; Warde, Ann M; Hall, James; Pyć, Cynthia; Clark, Christopher W

    2013-12-01

    Autonomous passive acoustic recorders were deployed to record sounds of bowhead whales (Balaena mysticetus) in the southeast Beaufort Sea for periods of 30-55 days during the late summer, open-water seasons of 2008-2010. Recordings were made in three areas licensed for hydrocarbon exploration, spanning the continental slope and adjacent outer shelf, and in a shallow inner-shelf area where bowheads have been observed congregating to feed in recent decades. Bowhead sounds were counted in samples comprising 10% of each recorded hour. In mid-August and September in all 3 years, the rate of bowhead calling at outer shelf sites exceeded that at adjacent continental slope sites by one to two orders of magnitude. Higher rates of calling occurred on the slope in late July and early August than at later dates. Calling rates varied by an order of magnitude between years in the one area that was monitored in different years. The highest rates of calling occurred on the inner shelf, offshore of the northern Tuktoyaktuk Peninsula. These trends are consistent with patterns of habitat use previously reported from aerial surveys in this and nearby areas of the Beaufort Sea and with the results of satellite tagging studies. PMID:25669244

  9. Horizontal Divergence and Vertical Velocity Adjacent to the Pyrenees Measured During the Boundary Layer Late Afternoon & Sunset Turbulence (BLLAST) Experiment

    NASA Astrophysics Data System (ADS)

    Faloona, I. C.; Lothon, M.

    2014-12-01

    Because of the dominant influence of surface solar heating on atmospheric boundary layer (ABL) flows, the character and even underlying theories of turbulence vary diurnally over the continents. While great strides have been made in our understanding of the stable boundary layers that prevail overnight, the period of transition from a convective daytime to a stable nighttime ABL remains a very challenging problem in no small part because of its inherently non-stationary nature and because both of the main forcings, wind stress and surface heat flux, tend to flag at this time of day. These underexplored topics motivated the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field experiment held in the summer of 2011 at the CNRS Laboratorie d'Aerologie in Campistrous, France. On three of the twelve intensive observational days of the experiment, three rawinsondes were launched simultaneously approximately 3 km apart throughout the afternoon transition in order to directly measure mesoscale horizontal divergence in the ABL and lower free troposphere. Using the assumption of incompressibility, the observed divergence is integrated and a vertical profile of mean vertical wind is derived for the lower troposphere. Although the magnitude of the inferred vertical winds are much larger than expected (of order 0.1 ms-1), the measurements do indicate a clear trend in afternoon subsidence giving way to evening uplift at the site, which is within ~10 km of the Pyrenees' foothills. The observed transition from low-level divergence to convergence was accompanied by a deep surface pressure minimum that fluctuated by nearly 300 Pa diurnally, and we propose that it is likely related to the reversal of the plain-mountain circulation across the region. The impact of such behavior on boundary layer growth and entrainment during the afternoon hours are discussed along with evidence of similar behavior observed elsewhere in mountainous terrain.

  10. Late Cretaceous paleomagnetism of the Tucson Mountains: implications for vertical axis rotations in south central Arizona

    USGS Publications Warehouse

    Hagstrum, J.T.; Lipman, P.W.

    1991-01-01

    The Tucson Mountains of southern Arizona are the site of an Upper Cretaceous caldera from which the rhyolitic Cat Mountain Tuff was erupted at about 72 Ma. Two magnetic units within the Cat Mountain Tuff are distinguished by paleomagnetic data in both the northern and southern Tucson Mountains. The available paleomagnetic data indicate that rocks in southern Arizona have not remained unrotated with respect to North America since Late Cretaceous time and that vertical axis rotations may have played an important role in the region during Laramide deformation. -from Authors

  11. Distribution and Diet of 0+ Fish within a Canyon-Shaped European Reservoir in Late Summer

    NASA Astrophysics Data System (ADS)

    Vaek, Mojmír; Kubeka, Jan; Matna, Josef; Sea, Jaromír

    2006-05-01

    The distribution and diet of age 0+ fish were studied in the deep canyon-shaped ímov Reservoir (Czech Republic), which is characterized by a longitudinal trophic gradient. During late summer of two years, 0+ fish were sampled from inshore and offshore habitats along the longitudinal reservoir axis. Offshore catches of 0+ fish from the surface layer were dominated by roach (Rutilus rutilus ), bream (Abramis brama ) and perch (Perca fluviatilis ), whereas in the deeper open water perch predominated. Inshore catches of 0+ fish were constituted mainly by perch and roach. The proportions of roach in the inshore catches were highest at the upper and most eutrophic part of the reservoir, whereas the proportions of perch in the inshore catches were higher at the downstream areas. Total catches of both inshore and offshore 0+ fish increased upstream in the reservoir. Offshore 0+ perch were of consistently smaller size than inshore 0+ perch. Inshore 0+ perch had significantly smaller size at the upstream reservoir part than at the downstream, more lacustrine regions. The diet of both inshore and offshore 0+ fish consisted predominantly of crustacean zooplankton. Perch diet was generally dominated both by cladocerans and copepods, whereas roach diet consisted chiefly of cladocerans.

  12. Analysis of a chemical defense in sawfly larvae: easy bleeding targets predatory wasps in late summer.

    PubMed

    Müller, Caroline; Brakefield, Paul M

    2003-12-01

    Contact of certain sawfly larvae with predators frequently elicits an easy bleeding behavior involving local disruption of the integument and release of hemolymph droplets. The efficacy of this putative antipredator defense was investigated in the turnip sawfly, Athalia rosae, by using common garden experiments in which particular guilds of predators were excluded, and through manipulations of the chemical defense of larval prey. After 3 d of exposure to walking and/or flying arthropod predators, the proportion of surviving sawfly larvae remained quite high at 71.3% in midsummer, but dropped to 37.5% in late summer. However, Pieris rapae caterpillars without the bleeding defense were killed within hours by predatory wasps (Vespula vulgaris). Topical treatment of P. rapae caterpillars with sawfly hemolymph or sinalbin, a glucosinolate sequestered by the sawflies, revealed that the easy bleeding of A. rosae is an efficient defense against wasps, partially due to this compound. These experiments are the first to demonstrate the efficacy of this chemical defense mechanism in a natural setting. PMID:14969355

  13. Late-summer food of red-winged blackbirds in a fresh tidal-river marsh

    USGS Publications Warehouse

    Meanley, B.

    1961-01-01

    During late summer in the Delaware Valley and Chesapeake Bay region, hundreds of thousands of Red-winged Blackbirds feed in wild rice beds of fresh tidal-river marshes. The period during which wild rice seed is available coincides with the ripening period of a part of the corn crop, and there is evidence to indicate that the availability of the wild rice reduces bird feeding pressure on corn in the area. The importance of wild rice and other marsh plants to the redwing during the period when wild rice seed is available was studied further by field observations and by analysis of stomach contents of 130 birds collected in wild rice beds of the Patuxent River in southern Maryland. Seeds of marsh plants formed the bulk of the food of redwings collected. Dotted smartweed, wild rice, and Walter?s millet were the most important food plants. Corn was the fourth most important item. It occurred in 35, approximately one-fourth, of the stomachs

  14. Wetting and greening Tibetan Plateau in early summer since the late 1970s due to advanced Asian summer monsoon onset

    NASA Astrophysics Data System (ADS)

    Zhang, Wenxia; Zhou, Tianjun; Zhang, Lixia

    2016-04-01

    Known as the "the world water tower", the Tibetan Plateau (TP) is the origin of the ten largest rivers in Asia, breeding more than 1.4 billion people, and exerts substantial influences on water resources, agriculture, and ecosystems in downstream countries. This region is one of the most susceptible areas around the world to changing climate due to the high elevation. Observed evidence have shown significant climate changes over the TP, including surface air warming and moistening, glaciers shrinking, winds stilling, solar dimming, and atmospheric heat source weakening. However, as an essential part of the hydrological cycle, precipitation changes on the TP remain an ambiguous picture. Changes in precipitation vary largely with different seasons, time periods and climate zones considered. This study shows a robust increase in precipitation amount over the TP in May, when the rainy season starts, over the period 1979-2014 (31% relative to the climatology). The wetting trend is spatially consistent over the south-eastern TP, to which both precipitation frequency and intensity contribute. Circulation trends show that the wetting TP in May is resulted from the advanced onset of Asian summer monsoon, which onsets 1~2 pentads earlier since 1979. It intensified water vapor transport from the Bay of Bengal (BOB) to south of the TP in May and local anomalous convection. This relationship is further validated by the significant correlation coefficient (0.47) between the onset dates of Asian summer monsoon (particularly the BOB summer monsoon, 0.68) and precipitation over the south-eastern TP in May. The wetting TP in May has further exerted profound impacts on the hydrological cycle and ecosystem, such as moistening the soil and animating vegetation activities throughout early summer. Both decadal variations of soil moisture (from May to June) and Normalized Difference Vegetation Index (NDVI) (from May to July) coincide well with that of precipitation over the south

  15. Features of the vertical phytoplankton structure in the deep-sea parts of the Caspian Sea in summer

    NASA Astrophysics Data System (ADS)

    Pautova, L. A.; Kravchishina, M. D.; Vostokov, S. V.; Zernova, V. V.; Silkin, V. A.

    2015-06-01

    The new features of the vertical phytoplankton distribution in the central and southern deep-water parts of the Caspian Sea are identified on the basis of long-term observations (2004-2012, 419 samples). Systematic study of phytoplankton in the Middle Caspian for nine years has shown that the interannual variability in the dominant summer phytoplankton complex is due to traditional species of diatoms and dinoflagellates and also coccolithophores, a new systematic group for the Caspian Sea (June 2010). It was first determined that summer phytoplankton of the deep-water parts in the Middle and Southern Caspian is similar in species, quantitative, and spatial (vertical) structure. A zone of higher phytoplankton productivity was first found in the area of the Absheron Sill. Two types of communities and their boundary were first distinguished in the vertical structure of summer phytoplankton of the deep-sea parts: warm-water and cold-water (below the thermocline). The boundary between them corresponds to the lower boundary of the seasonal thermocline (maximum depths up to 50-60 m) with the highest wet total phytoplankton biomass and chlorophyll a concentrations. The intensity of stratification of the water column by temperature mainly causes the vertical phytoplankton structure. The anomalously large deep-sea accumulations of diatoms cells containing chlorophyll (remains of winter-spring blooms) were first found in the near-bottom layers of the northern slope of the Derbent Depression. Their presence at the depths of 300-400 m is probably caused by the slope cascading. The lower boundary (500 m) of phytoplankton abundance in the Caspian Sea with chlorophyll-containing cells of fresh water green algae were registered by the authors for the first time in the central areas of the Derbent and South Caspian depressions. This phenomenon was caused by the contribution of cold Caucasus rivers through a system of submarine canyons from the shelf to the deep sea areas.

  16. Separation of Changes in Hydroclimatic and Basin Controls on Late-Summer Low Flow in British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Stahl, K.; Moore, R. D.; Allen, D. M.; Whitfield, P. H.

    2009-12-01

    For catchments in the Pacific Northwest of North America with minimal or no glacier cover, the summer period is typically dominated by low flows associated with the relatively warm, dry summers in that region. In recent years summer low flow has become more critical in terms of water use and fisheries, and there is increasing concern regarding effects of future climate change. In particular, it is expected that earlier snowmelt timing in spring causes longer recession periods and consequently lower streamflow during late summer. This study examined the sensitivity of late summer flows of 153 ‘unregulated’ rivers over the period 1976-2003 to hydroclimatic influences using trend tests accounting for exogenous variables by regression. Regression models were fitted using simultaneous and lagged variables of precipitation and timing and magnitude of snowmelt. The residuals were tested for trends and serial correlation to assess potential secondary influences such as long-term groundwater storage changes or mid-term changes in evapotranspiration. The decrease in September flows found across most of the region is broadly consistent with a decline in September precipitation. The most important control on August flows for all streamflow regimes is August precipitation. The influence of lagged variables including snowmelt timing varies. Rain-dominated and hybrid catchments along the coast tended to have positive trends in their residuals in August, suggesting an increasing trend in groundwater storage. Snowmelt dominated catchments show varied trends but the runs test detected a substantial number of stations with non-random residuals, suggesting mid-term secondary influences possibly associated with evapotranspiration changes due to progressive forest harvesting. This regional study greatly improves the understanding of the hydroclimatic influences on extreme summer low flow in the region. Results suggest that (the less predictable) summer climate is a larger influence

  17. Late-Summer Tundra Methane Concentrations and Fluxes on the North Slope of Alaska

    NASA Astrophysics Data System (ADS)

    Smith, J. P.; Suriben, R. S.; Coffin, R. B.; Boyd, T. J.; Rose, P. S.; Douglas, T. A.; Millholland, L. C., IV; Boudart, E. R.; Woods, J. E.

    2014-12-01

    Scientific evidence indicates wide-scale changes in Arctic climate. The Arctic contains large expanses of tundra with permafrost, or permanently frozen subsoil. Climate change impacts on the tundra have the potential to enhance biogenic methane (CH4) production in thawed, active soils or release CH4 trapped in or below the permafrost. Methane is a highly effective greenhouse gas so CH4 released from thawing tundra or melting massive ice features constitutes a potential positive feedback to Arctic climate change. In August, 2013 the U.S. Naval Research Laboratory (NRL-6114) led an expedition to investigate late-summer tundra CH4 concentrations and fluxes on the North Slope of Alaska near Prudhoe Bay. Permafrost cores were collected to measure tundra CH4 concentrations and soil parameters and a series of gas traps were deployed to measure tundra CH4 flux at 9 locations spread across a study area of ~1800 km2. Thaw probe measurements at each site provided information on the depth of the seasonally-thawed (active) layer. Results show large differences in tundra CH4 concentrations with depth through the active layer and into the upper permafrost terrain and fine-scale variability in daily CH4 flux over a relatively small spatial area. It is likely that variations in biogeochemical and geomorphological characteristics such as soil composition, microbial activity, moisture type, active layer composition and extent from site-to-site control the CH4 regime. In order to provide more accurate estimates of permafrost tundra CH4 storage and fluxes, controls on CH4 variability from location to location must be better understood. Further research is required to quantify and predict tundra CH4 flux in order to better understand the potential impact it will have on Arctic climate, particularly if, as predicted, climate warming leads to the liberation of permafrost carbon in these landscapes.

  18. Influence of Amur River discharge on phytoplankton photophysiology in the Sea of Okhotsk during late summer

    NASA Astrophysics Data System (ADS)

    Isada, Tomonori; Iida, Takahiro; Liu, Hongbin; Saitoh, Sei-Ichi; Nishioka, Jun; Nakatsuka, Takeshi; Suzuki, Koji

    2013-04-01

    We investigated the photosynthetic parameters of phytoplankton in the Sea of Okhotsk during the late summer of 2006 to characterize their spatiotemporal variability and to test the hypothesis that discharge from the Amur River could influence the algal photophysiology. The highest maximum quantum yield of carbon fixation in photosynthesis (Φcmax; 0.098 mol C mol photons-1) was found near the Amur River mouth, where nitrate was depleted. However, none of the photosynthetic parameters, including primary productivity (PP) at the surface, were correlated with temperature, daily photosynthetically available radiation (PAR), or ambient nutrient concentrations. Variations in Φcmax depended on the variations in not only the mean chlorophyll a specific absorption coefficient of phytoplankton (ā*ph) but also the slope index of the absorption coefficient of phytoplankton (aph slope), an indicator for the ratio of nonphotosynthetic carotenoids to photosynthetic carotenoids. These results indicated that the phytoplankton assemblages acclimated to the ambient light conditions by regulating their cellular pigments. Additionally, ā*ph and euphotic depth (Zeu) were significantly correlated with salinity, suggesting that photoacclimation of the phytoplankton assemblages observed in this study could be induced by discharge of Amur River. Because spatiotemporal variations in PP were concomitant with Φcmax, ā*ph, and the chlorophyll a concentration, PP models based on inherent optical property (IOP) were suitable for estimating PP in the Sea of Okhotsk. This study is the first to investigate the factors controlling phytoplankton photophysiology in the Sea of Okhotsk, one of the highest primary production areas in the world.

  19. Organic matter production during late summer-winter period in a temperate sea

    NASA Astrophysics Data System (ADS)

    Marić, Daniela; Frka, Sanja; Godrijan, Jelena; Tomažić, Igor; Penezić, Abra; Djakovac, Tamara; Vojvodić, Vjeročka; Precali, Robert; Gašparović, Blaženka

    2013-03-01

    The quantity and quality of fresh organic matter (OM) formed by primary production in relation to phytoplankton community structure was calculated for the late summer-winter 2009/2010 in the northern Adriatic Sea (Mediterranean). Phytoplankton species, as a direct measure of fresh OM, chlorophyll a, the OM pool (DOC and POC) and lipids, including classes, were analyzed. Data for temperature, salinity and nutrients enabled deeper insight into the conditions that promoted fresh OM production and associated processes at two stations of different trophic status. Phytoplankton growth was controlled by bottom regenerated nutrients and to lesser extent by riverine nutrients. The phytoplankton community was mainly dominated by nanoplankton. Species of moderate carbon content Chaetoceros compressus, Asterionellopsis glacialis, Leptocylindrus danicus and Bacteriastrum jadranum dominated the microplankton fraction. Availability of orthophosphates was the key factor influencing fresh OM production. POC varied from 37-522 μg l-1. Freshphyto POC, i.e. carbon fixed in phytoplankton cells, contributed 7-79% to the POC pool. The DOC (890-1560 μg l-1) level decreased during the investigated period. Calculation of fresh DOC, i.e. carbon fixed during primary production and released as dissolved OM, revealed it as a minor part (0-2%) of the DOC pool. Lipid concentrations varied from 9.9-55.0 μg l-1 and 20.0-40.2 μg l-1 in the particulate and dissolved fractions, respectively. Nutrient limitation caused increased synthesis of lipids, among which energy reserve lipids triacylglycerols, which are further immobilized for the construction of glycolipids with increasing depletion of orthophosphates.

  20. Late Holocene Asian summer monsoon variability reflected by δ18O in tree-rings from Tibetan junipers

    NASA Astrophysics Data System (ADS)

    Grießinger, Jussi; Bräuning, Achim; Helle, Gerd; Thomas, Axel; Schleser, Gerhard

    2011-02-01

    Recent warming in High Asia might have a strong impact on Asian summer monsoon variability with consequences for the hydrological cycle. Based on correlations between climate data, the tree-ring δ18O of high-elevation junipers is an indicator of August precipitation. Thus, our 800-year long annually resolved oxygen isotope series reflects long-term variations in summer monsoon activity on the southern Tibetan plateau. Summer precipitation was reduced during 13th-15th centuries and since the 19th century, whereas the Little Ice Age period (15th-19th century) was rather moist. The late 20th century was among the driest periods during the past 800 years, showing a tendency to slightly wetter conditions after AD 1990.

  1. Vertical tectonics in northern Escanaba Trough as recorded by thick late Quaternary turbidites

    USGS Publications Warehouse

    Normark, W.R.; Serra, F.

    2001-01-01

    Escanaba Trough, the southernmost segment of the Gorda Ridge, is filled by as much as 500 m of late Quaternary turbidite and hemipelagic sediment. Coring at Deep Sea Drilling Project Site 35 and Ocean Drilling Program (ODP) Sites 1037 and 1038 together with 4.5-kHz deep-tow and 3.5-kHz surface-ship seismic reflection profiles enable a distinct pattern of reflections to be mapped throughout Escanaba Trough in the upper part of this sediment fill. The uppermost 80 m of turbidite sediment, which includes at least 11 turbidity current events, were deposited in 3200 m. The turbidity currents were trapped upon entering Escanaba Trough, resulting in all of the sediment in suspension in the flows being deposited. The thickness of the turbidite layers reflects both the flow thickness and the vertical grain concentration within the flow that deposited the layer. Variations in the turbidite thickness with respect to water depth can be used to estimate the degree of relative vertical movement within the floor of Escanaba Trough. In the area of hydrothermal activity near ODP Site 1038, uplift of as much as 140 m has occurred over the past 8 kyr. Copyright 2001 by the American Geophysical Union.

  2. Multi-Summer Climatology of Cumuli at SGP site: Vertical Structure

    SciTech Connect

    Kassianov, Evgueni I.; Berg, Larry K.

    2011-10-01

    We perform a case study for estimating the impact of the vertical distribution of cloud fraction on the normalized cloud radiative forcing (CRF) using a decade-long (2000-2009) high resolution dataset of cloud macrophysical and radiative properties. This dataset is developed for fair-weather cumuli (FWC) observed at the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site. The design of the case study reduces effects associated with non-cloud factors, such as the diurnal changes of aerosol loading and solar zenith angle. The results of the case study suggest that the impact of the vertical cloud structure can be substantial. Therefore, taking into account the vertical distribution of clouds would be beneficial for more comprehensive parameterizations aimed to portray the complex interactions between clouds and radiation more accurately

  3. Uniform summer cooling drove glacier re-advance across New Zealand during the late-glacial climate reversal

    NASA Astrophysics Data System (ADS)

    Eaves, S.; Mackintosh, A. N.; Winckler, G.; Schaefer, J. M.; Anderson, B.; Townsend, D.

    2014-12-01

    Rapid, millennial-scale climate events characterised the last global glacial-interglacial transition (18-11 ka). In New Zealand, the timing and magnitude of climatic events during this period are poorly understood. Improving our understanding of these events will help to identify the mechanisms via which rapid shifts in climate occur. In this study, we report results from geomorphological mapping, cosmogenic 3He exposure dating and numerical glacier modelling, which show evidence for re-advance of mountain glaciers on Mt Ruapehu in central North Island, New Zealand (39°S) during the late glacial chron (15-11 ka). Using a distributed energy balance model, coupled with a 2D ice flow model, we perform a range of experiments and sensitivity analyses to constrain estimates of past temperature associated with the mapped and dated former ice limits. We find that glaciers in North Island re-advanced early in the late glacial period in response to a likely temperature cooling of 2.5 - 3.4 °C relative to present day, assuming precipitation remained within ± 20% of present. This reconstructed cooling is greater than recorded in nearby pollen archives, which may reflect a seasonal bias between climate proxies. Using our glacier model, we quantify the length sensitivity of glaciers on Mt. Ruapehu to seasonal climate changes. We find that a 3 °C cooling relative to present causes a c. 80% increase in glacier length when applied to the austral summer months (Dec-Feb), compared to c. 20% in winter (June-August). Thus, glaciers in North Island, New Zealand are most sensitive to temperature changes during summer. Strong agreement between our late-glacial reconstructions and other summer temperature proxy records (e.g. mountain glaciers, chironomids) from the Southern Alps, suggest New Zealand experienced uniform summertime cooling during the late-glacial climate reversal.

  4. Zooplankton data: Vertical distributions of zooplankton in the Norweigian and Greenland Seas during summer, 1989

    SciTech Connect

    Lane, P.V.Z.; Smith, S.L.; Schwarting, E.M.

    1993-08-01

    Recent studies of zooplankton populations in the Greenland Sea have focused on processes at the Marginal Ice Zone (MIZ) and the areas immediately adjacent to it under the ice and in open water. These studies have shown a relatively short period of intense secondary productivity which is closely linked temporally and spatially to phytoplankton blooms occurring near the ice edge in spring and early summer. During the summer of 1989 we participated in a project focusing on benthic and water column processes in the basins of the Norwegian and Greenland Seas. This study allowed us to compare biological processes at the MIZ with those occurring in the open waters of the Greenland Sea, and to compare processes at both of these locations with those in the Norwegian Sea. The data presented in this report are the results of zooplankton net tows covering the upper 1000 meters of the water column over the Norwegian Sea basin and the Greenland Sea basin, and the upper 500 meters of open water adjacent to the MIZ in the Greenland Sea. Sampling was conducted between 12 and 29 July 1989.

  5. Evolution of Vertical Moist Thermodynamic Structure Associated with the Indian Summer Monsoon 2010 in a Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Raju, A.; Parekh, Anant; Gnanaseelan, C.

    2014-07-01

    The 2010 boreal summer marked a worldwide abnormal climate. An unprecedented heat wave struck East Asia in July and August 2010. In addition to this, the tropical Indian Ocean was abnormally warm during the summer of 2010. Several heavy rainfall events and associated floods were also reported in the Indian monsoon region. During the season, the monsoon trough (an east-west elongated area of low pressure) was mostly located south of its normal position and monsoon low pressure systems moved south of their normal tracks. This resulted in an uneven spatial distribution with above-normal rainfall over peninsular and Northwest India, and deficient rainfall over central and northeastern parts of India, thus prediction (and simulation) of such anomalous climatic summer season is important. In this context, evolution of vertical moist thermodynamic structure associated with Indian summer monsoon 2010 is studied using regional climate model, reanalysis and satellite observations. This synergised approach is the first of its kind to the best of our knowledge. The model-simulated fields (pressure, temperature, winds and precipitation) are comparable with the respective in situ and reanalysis fields, both in intensity and geographical distribution. The correlation coefficient between model and observed precipitation is 0.5 and the root-mean-square error (RMSE) is 4.8 mm day-1. Inter-comparison of model-simulated fields with satellite observations reveals that the midtropospheric temperature [Water vapour mixing ratio (WVMR)] has RMSE of 0.5 K (1.6 g kg-1), whereas the surface temperature (WVMR) has RMSE of 3.4 K (2.2 g kg-1). Similarly, temporal evolution of vertical structure of temperature with rainfall over central Indian region reveals that the baroclinic nature of monsoon is simulated by the model. The midtropospheric warming associated with rainfall is captured by the model, whereas the model failed to capture the surface response to high and low rainfall events. The

  6. The vertical structure of cloud radiative heating over the Indian subcontinent during summer monsoon

    NASA Astrophysics Data System (ADS)

    Johansson, E.; Devasthale, A.; L'Ecuyer, T.; Ekman, A. M. L.; Tjernström, M.

    2015-02-01

    Every year the monsoonal circulation over the Indian subcontinent gives rise to a variety of cloud types that differ considerably in their ability to heat or cool the atmosphere. These clouds in turn affect monsoon dynamics via their radiative impacts, both at the surface and in the atmosphere. New generation of satellites carrying active radar and lidar sensors are allowing realistic quantification of cloud radiative heating (CRH) by resolving the vertical structure of the atmosphere in an unprecedented detail. Obtaining this information is a first step in closing the knowledge gap in our understanding of the role that different clouds play as regulators of the monsoon and vice versa. Here, we use collocated CloudSat-CALIPSO data sets to understand following aspects of cloud-radiation interactions associated with Indian monsoon circulation. (1) How does the vertical distribution of CRH evolve over the Indian continent throughout monsoon season? (2) What is the absolute contribution of different clouds types to the total CRH? (3) How do active and break periods of monsoon affect the distribution of CRH? And finally, (4) what are the net radiative effects of different cloud types on surface heating? In general, the vertical structure of CRH follows the northward migration and the retreat of monsoon from May to October. It is found that the alto- and nimbostratus clouds intensely warm the middle troposphere and equally strongly cool the upper troposphere. Their warming/cooling consistently exceeds ±0.2 K day-1 (after weighing by vertical cloud fraction) in monthly mean composites throughout the middle and upper troposphere respectively, with largest impact observed in June, July and August. Deep convective towers cause considerable warming in the middle and upper troposphere, but strongly cool the base and inside of the tropical tropopause layer (TTL). Such cooling is stronger during active (-1.23 K day-1) monsoon conditions compared to break periods (-0.36 K day-1

  7. Vertical biogenic particle flux during Austral summer in the Antarctic Peninsula area

    NASA Astrophysics Data System (ADS)

    Anadón, Ricardo; Alvarez-Marqués, Florentina; Fernández, Emilio; Varela, Manuel; Zapata, Manuel; Gasol, Josep M.; Vaqué, Dolors

    During both FRUELA cruises, we performed eight circum-diel stations in the Bellingshausen Sea (South of Drake Passage), and the Bransfield and Gerlache straits, where MULTITRAP sediment-traps were deployed for periods of 24 h in order to study carbon (C) and nitrogen (N) export from the photic layer. Two types of regions were visited: High chlorophyll a (Chl a) areas dominated by large-sized diatoms (>10 μm), and low Chl a areas dominated by Cryptomonas sp. or microflagellates. The vertical fluxes of C, N, and Chl a, and the number of fecal pellets (FP) were measured, and the taxonomic composition of the sedimented microplankton was analysed; the results compared to the standing stocks in the water column overlaying the sediment traps. We measured higher carbon export rates in the diatom-dominated regions (Gerlache Strait), than in the stations dominated by small phytoplankton (Bransfield Strait and Bellingshausen Sea). The measured C-fluxes ranged from 115 to 800 mg C m -2 day -1. Typical C : N ratio (by atoms) varied from 5.5 to 16.4. Nitrogen export, however, was not directly related to C export and, thus, we measured changes in the C : N ratio with stations having higher abundance of FP or detritus presenting higher C : N ratios. Variations in the vertical C-flux were related to biological variables such as FP number, algal community composition (quantitative counts and qualitative SEM observations), and photosynthetic and prokaryotic activity of the sedimented material. We calculated photic layer loss rates of C, N, Chl a (0.53-8.0% day -1) and of the different microplankton taxonomic entities (0.27-9.5% day -1). Some exceptionally high loss values were found for Cryptophyceae during Fruela 96. The obtained results are discussed within the conceptual framework set by the relationships between phytoplankton size and food web structure, and concomitant carbon export from the photic layer.

  8. Late summer sea ice segmentation with multi-polarisation SAR features in C- and X-band

    NASA Astrophysics Data System (ADS)

    Fors, A. S.; Brekke, C.; Doulgeris, A. P.; Eltoft, T.; Renner, A. H. H.; Gerland, S.

    2015-09-01

    In this study we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg-fast first-year and old sea ice during a week with air temperatures varying around zero degrees Celsius. In situ data consisting of sea ice thickness, surface roughness and aerial photographs were collected during a helicopter flight at the site. Six polarimetric SAR features were extracted for each of the scenes. The ability of the individual SAR features to discriminate between sea ice types and their temporally consistency were examined. All SAR features were found to add value to sea ice type discrimination. Relative kurtosis, geometric brightness, cross-polarisation ratio and co-polarisation correlation angle were found to be temporally consistent in the investigated period, while co-polarisation ratio and co-polarisation correlation magnitude were found to be temporally inconsistent. An automatic feature-based segmentation algorithm was tested both for a full SAR feature set, and for a reduced SAR feature set limited to temporally consistent features. In general, the algorithm produces a good late summer sea ice segmentation. Excluding temporally inconsistent SAR features improved the segmentation at air temperatures above zero degrees Celcius.

  9. Late-summer sea ice segmentation with multi-polarisation SAR features in C and X band

    NASA Astrophysics Data System (ADS)

    Fors, Ane S.; Brekke, Camilla; Doulgeris, Anthony P.; Eltoft, Torbjørn; Renner, Angelika H. H.; Gerland, Sebastian

    2016-02-01

    In this study, we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg-fast first-year and old sea ice during a week with air temperatures varying around 0 °C. Sea ice thickness, surface roughness and aerial photographs were collected during a helicopter flight at the site. Six polarimetric SAR features were extracted for each of the scenes. The ability of the individual SAR features to discriminate between sea ice types and their temporal consistency were examined. All SAR features were found to add value to sea ice type discrimination. Relative kurtosis, geometric brightness, cross-polarisation ratio and co-polarisation correlation angle were found to be temporally consistent in the investigated period, while co-polarisation ratio and co-polarisation correlation magnitude were found to be temporally inconsistent. An automatic feature-based segmentation algorithm was tested both for a full SAR feature set and for a reduced SAR feature set limited to temporally consistent features. In C band, the algorithm produced a good late-summer sea ice segmentation, separating the scenes into segments that could be associated with different sea ice types in the next step. The X-band performance was slightly poorer. Excluding temporally inconsistent SAR features improved the segmentation in one of the X-band scenes.

  10. Amplified melt and flow of the Greenland ice sheet driven by late-summer cyclonic rainfall

    NASA Astrophysics Data System (ADS)

    Doyle, Samuel H.; Hubbard, Alun; van de Wal, Roderik S. W.; Box, Jason E.; van As, Dirk; Scharrer, Kilian; Meierbachtol, Toby W.; Smeets, Paul C. J. P.; Harper, Joel T.; Johansson, Emma; Mottram, Ruth H.; Mikkelsen, Andreas B.; Wilhelms, Frank; Patton, Henry; Christoffersen, Poul; Hubbard, Bryn

    2015-08-01

    Intense rainfall events significantly affect Alpine and Alaskan glaciers through enhanced melting, ice-flow acceleration and subglacial sediment erosion, yet their impact on the Greenland ice sheet has not been assessed. Here we present measurements of ice velocity, subglacial water pressure and meteorological variables from the western margin of the Greenland ice sheet during a week of warm, wet cyclonic weather in late August and early September 2011. We find that extreme surface runoff from melt and rainfall led to a widespread acceleration in ice flow that extended 140 km into the ice-sheet interior. We suggest that the late-season timing was critical in promoting rapid runoff across an extensive bare ice surface that overwhelmed a subglacial hydrological system in transition to a less-efficient winter mode. Reanalysis data reveal that similar cyclonic weather conditions prevailed across southern and western Greenland during this time, and we observe a corresponding ice-flow response at all land- and marine-terminating glaciers in these regions for which data are available. Given that the advection of warm, moist air masses and rainfall over Greenland is expected to become more frequent in the coming decades, our findings portend a previously unforeseen vulnerability of the Greenland ice sheet to climate change.

  11. Vitamin D status and its determinants in children and adults among families in late summer in Denmark.

    PubMed

    Madsen, Katja H; Rasmussen, Lone B; Mejborn, Heddie; Andersen, Elisabeth W; Mølgaard, Christian; Nissen, Janna; Tetens, Inge; Andersen, Rikke

    2014-09-14

    The impact of the familial relationship on vitamin D status has not been investigated previously. The objective of the present cross-sectional study was to assess serum 25-hydroxyvitamin D (25(OH)D) concentration and its determinants in children and adults among families in late summer in Denmark (56°N). Data obtained from 755 apparently healthy children (4-17 years) and adults (18-60 years) recruited as families (n 200) in the VitmaD study were analysed. Blood samples were collected in September-October, and serum 25(OH)D concentration was measured by liquid chromatography-tandem MS. Information on potential determinants was obtained using questionnaires. The geometric mean serum 25(OH)D concentration was 72·1 (interquartile range 61·5-86·7) nmol/l (range 9-162 nmol/l), with 9 % of the subjects having 25(OH)D concentrations < 50 nmol/l. The intra-family correlation was 0·27 in all subjects, 0·24 in the adults and 0·42 in the children. Serum 25(OH)D concentration was negatively associated with BMI (P< 0·001) and positively associated with dietary vitamin D intake (P= 0·008), multivitamin use (P= 0·019), solarium use (P= 0·006), outdoor stay (P= 0·001), sun preference (P= 0·002) and sun vacation (P< 0·001), but was not associated with lifestyle-related factors in the adults when these were assessed together with the other determinants. In conclusion, the majority of children and adults among the families had serum 25(OH)D concentrations >50 nmol/l in late summer in Denmark. Both dietary and sun-related factors were determinants of vitamin D status and the familial component was stronger for the children than for the adults. PMID:24932732

  12. Formulation of a wind specification for Titan late polar summer exploration

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Newman, Claire E.; Tokano, Tetsuya; Mitchell, Jonathan L.; Charnay, Benjamin; Lebonnois, Sebastien; Achterberg, Richard K.

    2012-09-01

    Titan's polar regions, and its hydrocarbon lakes in particular, are of interest for future exploration. The polar conditions have considerable seasonal variation and are distinct from the equatorial environment experienced by Huygens. Thus specific environmental models are required for these regions. This paper, informed by Cassini and groundbased observations and four independent Global Circulation Models (GCMs), summarizes northern summer polar conditions (specifically, regions north of 65°N, during the 2023-2024 period, or solar longitude Ls˜150o-170°) and presents a simple analytical formulation of expected, minimum and maximum winds as a function of altitude to aid spacecraft and instrument design for future exploration, with particular reference to the descent dispersions of the Titan Mare Explorer (TiME) mission concept presently under development. We also consider winds on the surface, noting that these (of relevance for impact conditions, for waves, and for wind-driven drift of a floating capsule) are weaker than those in the lowest cell in most GCMs: some previously-reported estimates of 'surface' wind speeds (actually at 90-500 m altitude) should be reduced by 20-35% to refer to the standard 10 m 'anemometer height' applicable for surface phenomena. A Weibull distribution with scale speed C=0.4 m/s and shape parameter k=2.0 embraces the GCM-predicted surface wind speeds.

  13. Contrasting ice sheet response to early and late summer rapid supraglacial lake drainage events on the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Stevens, L. A.; Behn, M. D.; Das, S. B.; Joughin, I. R.; Herring, T.; King, M. A.; McGuire, J. J.

    2013-12-01

    Across much of the ablation region of the western Greenland Ice Sheet, hydro-fracture events related to supraglacial lake drainages rapidly deliver large volumes of meltwater to the bed and create conduits providing efficient surface-to-bed drainage networks for the remainder of the summer melt season. Using a network of 20 GPS stations installed in 2011, and supplemented with a smaller network operating back to 2006, we observe ice surface motion during a series of lake draining hydro-fracture events. These data are used to investigate (1) the location and propagation geometry of the fracture opening and (2) the acceleration of ice in response to the rapid input of surface meltwater to the bed. Observations at the same location show varying surface motion following early versus late summer rapid lake drainage events from multiple years. During a late-season (July 29) rapid drainage in 2006, results from a single GPS station show velocity in the direction of mean ice flow and surface uplift returned to pre-drainage values within ~24 hours (Das et al., 2008), indicating the large subglacial meltwater pulse was efficiently dissipated into the subglacial hydrologic network. In contrast, an early-season (June 11) rapid drainage at the same lake in 2011 induced uplift that persisted for much longer. Specifically, we find that elevations at stations nearest the moulin did not return to pre-drainage elevations for 4 to 8 days post-drainage, suggesting a more inefficient subglacial hydrologic system during the early summer season. These results indicate that the ice-sheet response is modulated, at least in part, by the seasonal evolution of the subglacial hydrological system. We also plan to investigate new GPS data from 2 rapid drainage events in the early portion of the melt season in 2012 and 2013. Findings from these events will ultimately improve our understanding of the mechanics of ice-sheet hydro-fracture and the influence of surface meltwater on ice-sheet flow.

  14. Dynamic-analogue correction of the decadal change of East Asian summer precipitation in the late 1990s

    NASA Astrophysics Data System (ADS)

    Gong, Zhiqiang; Li, Shangfeng; Hu, Po; Shen, Baizhu; Feng, Guolin

    2016-06-01

    This paper systematically evaluates the deviations that appear in the hindcasts of the East Asian summer precipitation (EASP) decadal change in the late 1990s in two global coupled models (BCC_CGCM and BCC_CSM). The possible causes for the deviations between the model hindcasts and observations are analyzed. The results show that the hindcasts of EASP by BCC_CGCM and BCC_CSM deviate from observations, with the anomaly correlation coefficient (ACC) being -0.01 and -0.09 for the two models, respectively. The SST anomalies in North and West Pacific and the SST index values predicted by the two models also deviate from the observations, indicating that inconsistent SST fields may be the key factor leading to the deviation in the prediction of the EASP decadal shift. Thus, a dynamic-analogue scheme is proposed to correct the precipitation hindcasts by using SSTs, where SST and EASP are highly correlated, to select historical analogue cases. Cross validations show that the average ACC of the temporal-latitude distribution of the EASP between the corrected hindcasts and observations is 0.18 for BCC_CGCM and 0.02 for BCC_CSM; both are much higher than the uncorrected hindcasts. Applying the dynamic-analogue correction scheme in both models successfully improves prediction of the EASP decadal change in the late 1990s.

  15. Effect of the early and late onset of summer monsoon over the Bay of Bengal on Asian precipitation in May

    NASA Astrophysics Data System (ADS)

    Xing, Nan; Li, Jianping; Wang, Lanning

    2016-04-01

    The impact of early and late Bay of Bengal (BoB) summer monsoon (BoBSM) onset on Asian precipitation in May is investigated. When the BoBSM occurs earlier (later), May rainfall tends to be enhanced (suppressed) in the southern Indian peninsula (SIP), the Indochinese peninsula (ICP), southwest China (SWC) and the South China Sea (SCS), while south China (SC) rainfall tends to be suppressed (enhanced). When the BoBSM occurs earlier than the climatological mean (late April), strong convective activity emerges earlier over the BoB, which causes local strong convective heating earlier. Then, earlier spread of heating in the BoB towards both sides leads to earlier retreat of the subtropical highs in the western Pacific (WPSH) and Indian Ocean (IOSH) outwards the BoB. Thus, compared to the climatological mean, the two subtropical highs present larger retreat outwards the BoB and smaller meridional extent over the SCS and Arabian Sea in May, which contributes to positive heating anomalies over the SCS and Arabian Sea. Therefore, anomalous cyclonic circulations occur over the BoB, SCS and Arabian Sea in May. Anomalous cyclonic circulation is favorable for low-level convergence over the SIP, and thus resulting in local heavy rainfall. Associated with cyclonic circulation anomalies over the BoB and SCS, anomalous low-level convergent winds and ascending flows favor positive precipitation anomalies in the ICP, SWC, and SCS, while anomalous northeasterlies and descending flows affected by the southward retreat of the WPSH lessen SC rainfall. In late onset years the opposite occurs.

  16. Effect of the early and late onset of summer monsoon over the Bay of Bengal on Asian precipitation in May

    NASA Astrophysics Data System (ADS)

    Xing, Nan; Li, Jianping; Wang, Lanning

    2015-12-01

    The impact of early and late Bay of Bengal (BoB) summer monsoon (BoBSM) onset on Asian precipitation in May is investigated. When the BoBSM occurs earlier (later), May rainfall tends to be enhanced (suppressed) in the southern Indian peninsula (SIP), the Indochinese peninsula (ICP), southwest China (SWC) and the South China Sea (SCS), while south China (SC) rainfall tends to be suppressed (enhanced). When the BoBSM occurs earlier than the climatological mean (late April), strong convective activity emerges earlier over the BoB, which causes local strong convective heating earlier. Then, earlier spread of heating in the BoB towards both sides leads to earlier retreat of the subtropical highs in the western Pacific (WPSH) and Indian Ocean outwards the BoB. Thus, compared to the climatological mean, the two subtropical highs present larger retreat outwards the BoB and smaller meridional extent over the SCS and Arabian Sea in May, which contributes to positive heating anomalies over the SCS and Arabian Sea. Therefore, anomalous cyclonic circulations occur over the BoB, SCS and Arabian Sea in May. Anomalous cyclonic circulation is favorable for low-level convergence over the SIP, and thus resulting in local heavy rainfall. Associated with cyclonic circulation anomalies over the BoB and SCS, anomalous low-level convergent winds and ascending flows favor positive precipitation anomalies in the ICP, SWC, and SCS, while anomalous northeasterlies and descending flows affected by the southward retreat of the WPSH lessen SC rainfall. In late onset years the opposite occurs.

  17. Late Pleistocene-Holocene vegetation and Indian summer monsoon record from the Lahaul, Northwest Himalaya, India

    NASA Astrophysics Data System (ADS)

    Rawat, Suman; Gupta, Anil K.; Sangode, S. J.; Srivastava, Priyeshu; Nainwal, H. C.

    2015-04-01

    The high resolution Holocene paleomonsoon records from Northwest (NW) Himalaya are limited. The carbon isotope (δ13C), Total organic carbon (TOC) and pollen analysis were therefore carried out from a peat-lake sediment sequence developed in alpine meadows of the Chandra valley, Lahaul, NW Himalaya, in order to reconstruct centennial to millennial scale vegetational changes and Indian summer monsoon (ISM) variability during the Holocene. The chronology of peat-lake sediments is constrained with 9 AMS 14C dates. The recovered non-arboreal pollen (NAP) suggested that during Holocene alpine desert-steppe, meadows and shrubs growing along the stream had developed in the Lahaul valley whereas arboreal pollens (AP) e.g. Pinus, Quercus, Cedrus and Ulmus presently growing in the southern hill slopes of Pir Panjal range indicated moisture carrying monsoonal air flow from the South. The increased δ13C and low TOC values between ∼12,880 and 11,640 calibrated years before present (cal yr BP) suggested weakening of ISM and low organic carbon production corresponding to the Younger Dryas (YD) cold event. The gradual depletion in carbon isotope ratio from ∼11,640 to 8810 cal yr BP indicated enhanced precipitation in the Chandra valley in response of increased ISM strength in early Holocene. The short spell of cold and dry climate with gradual decrease in ISM intensity between ca 10,398 and 9778 cal yr BP is closely linked with Bond event-7. The other prominent cold-dry events recorded in present study are (i) ∼8810 to 8117 cal yr BP roughly corresponding to global 8.2 ka cold event, (ii) ∼4808 to 4327 cal yr BP closely preceding the global 4.2 ka cold-arid period, and (iii) ∼1303 to 1609 cal AD corresponding to Little Ice Age (LIA) event. The expansion of thermophillous broad leaved taxa viz. Betula utilis, Alnus nepalensis, Quercus semicarpifolia and Juglans regia and effective growth of meadow vegetation such as grasses, Caryophyllaceae and Artemisia along with

  18. Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

    NASA Astrophysics Data System (ADS)

    Pelto, M.

    2011-12-01

    On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient derived from the TSL and SWE measured in snowpits at 1000 m from 1998-2010 ranges from 2.6-3.8 mm m-1. Probing transects from 950 m-1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3-3.8 mm m-1. The TSL on Taku Glacier is identified in MODIS and Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004-2010 period to assess the consistency of its rate of rise and reliability in assessing ablation for mass balance assessment. For example, in 2010, the TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m-1, combined with the TSL rise of 3.7 m day-1 yields an ablation rate of 12.2 mm day-1 from mid-July to mid-Sept, 2010. The TSL rise in the region from 750-1100 m on Taku Glacier during eleven periods each covering more than 14 days during the ablation season indicates a mean TSL rise of 3.7 m day-1, the rate of rise is relatively consistent ranging from 3.1 to 4.4 m day-1. This rate is useful for ascertaining the final ELA if images or observations are not available near the end of the ablation season. The mean ablation from 750-1100 m during the July-September period determined from the TSL rise and the observed balance gradient is 11-13 mm day-1 on Taku Glacier during the 2004-2010 period. The potential for providing an estimate of bn from TSL observations late in the melt season from satellite images combined with the frequent availability of such images provides a means for efficient mass balance assessment in many years and on many glaciers.

  19. Ice-free summers predominant in the late Miocene central Arctic Ocean - New insights from a proxy-modeling approach

    NASA Astrophysics Data System (ADS)

    Stein, Ruediger; Fahl, Kirsten; Schreck, Michael; Knorr, Gregor; Forwick, Matthias; Lohmann, Gerrit; Niessen, Frank

    2016-04-01

    During Polarstern Expedition PS87/2014, we discovered multiple submarine landslides over a distance of >350 km along Lomonosov Ridge between about 81°N and 84°N (Stein, 2015). The load and erosional behaviour of an extended ice sheet/shelf that probably occurred during major Quaternary glaciations, may have caused physical conditions that triggered these landslides and major down-slope transport of sediments at this part of Lomonosov Ridge (Stein et al., 2016 and further references therein). The removal of younger sediments from steep headwalls has led to exhumation of Miocene to early Quaternary sediments close to the seafloor, allowing the retrieval of such old sediments by gravity coring and multi-proxy studies of theses sediments. Within one of these studies (Stein et al., 2016), we used for the first time the sea-ice biomarker IP25 (for background of approach see Belt et al., 2007; Müller et al., 2009, 2011) together with alkenone-based sea-surface temperatures (SST) to reconstruct upper Miocene Arctic Ocean sea-ice and SST conditions. The presence of IP25 as proxy for spring sea-ice cover and alkenone-based relatively warm summer SST of >4 °C support a seasonal sea-ice cover with an ice-free summer season being dominant during (most of) the late Miocene central Arctic Ocean. A comparison of our proxy data with Miocene climate simulations seems to favour either relatively high late Miocene atmospheric CO2 concentrations and/or an overly weak sensitivity of the model to simulate the magnitude of high-latitude warming in a warmer than modern climate. References: Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, and C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25, Organic Geochemistry 38, 16-27. Müller, J., Massé, G., Stein, R., and Belt, S., 2009. Extreme variations in sea ice cover for Fram Strait during the past 30 ka. Nature Geoscience, DOI: 10.1038/NGEO665. Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., and

  20. Herbage intake and milk production of late-lactation dairy cows offered a second-year chicory crop during summer.

    PubMed

    Muir, S K; Ward, G N; Jacobs, J L

    2015-12-01

    Chicory (Cichorum intybus L.) is a summer-active forage herb which has been proposed as an option to increase summer feed supply, increase dry matter intake, nutrient intake, and milk yield from nonirrigated dairy production systems in southern Australia. Dry matter intake, nutrient intake, milk yield, and yield of milk fat and protein of predominantly Holstein-Friesian dairy cows in late lactation consuming 3 herbage-based diets (4 replicates per treatment) were measured. The 3 grazed herbages were second-year chicory (CHIC) and perennial ryegrass (Lolium perenne L.; PRG) monocultures and a mixed sward (~50:50) of chicory and perennial ryegrass (MIX). All diets (CHIC, PRG, and MIX) were supplemented with alfalfa (Medicago sativa L.) hay (5.5kg of DM/cow per day) and an energy-based concentrate pellet (4.0kg of DM/cow per day). There were no significant differences in milk yield (12.0 to 12.6kg/d across the treatments) or the yield of milk fat (539 to 585g/d) and milk protein (433 to 447g/d) between the 3 herbage-based diets. No differences in DMI (17.9 to 19.2kg/d) or estimated metabolizable energy intake (173 to 185MJ/d) were noted between treatments. Estimated metabolizable energy concentrations in the forages on offer were lower in CHIC than PRG (7.6 vs. 8.2MJ/kg of dry matter), but the concentration in consumed herbage was not different (9.1 vs. 9.2MJ/kg of dry matter); as such, potential for increased milk yield in cows offered CHIC was limited. Increased concentration of polyunsaturated fatty acids was observed in chicory herbage compared with perennial ryegrass. This was associated with increased milk conjugated linoleic acid and milk polyunsaturated fatty acids when chicory formed part of the diet (CHIC compared to PRG and MIX). Chicory could be used as an alternative to perennial ryegrass in summer; however, the developmental stage of chicory will influence concentrations of metabolizable energy and neutral detergent fiber and, therefore, intake and milk

  1. Century-scale variability in late-summer rainfall events recorded over seven centuries in subannually laminated lacustrine sediments, White Pass, British Columbia

    NASA Astrophysics Data System (ADS)

    Cockburn, Jaclyn M. H.; Lamoureux, Scott F.

    2007-03-01

    Formation of annually laminated sediments in Summit Lake, White Pass, British Columbia is controlled by runoff generated by snowpack and glacier melt and major rainfall events. The 700-yr varve record is divided into two subannual series (early and late) based on sedimentological criteria and sedimentary structures within each varve. A comparison of recent subannual laminae with nearby meteorological records supports the interpretation they are formed by river discharge events generated by major snow and glacier melt events and large late-summer rainfall events. A significant correlation exists between the late subannual thickness series and the size of the largest rainfall events in late summer. The long record indicates there was an abrupt increase in the thickness and frequency of major rainfall-induced sedimentary events at the end of the seventeenth century. In addition, the frequency of laminae generated by early runoff events also increased. However, early subannual varve thickness component remains statistically the same as the thickness prior to the end of the seventeenth century. This suggests the change in varve thickness at this time is due to increases in major late-summer rainfall frequency rather than increased sediment availability caused by regional Little Ice Age glacier advances.

  2. Late summer heat-transfer regimes at adjacent permafrost and non-permafrost sites in central Alaska

    SciTech Connect

    Hinkel, K.M.; Nicholas, J. . Dept. of Geography); Outcalt, S.I. . Dept. of Geological Sciences)

    1992-01-01

    Hourly observations of soil temperature and a surrogate index of soil water ion concentration were collected during late summer from the upper 50 cm of soil at two adjacent sites in the discontinuous permafrost zone of central Alaska. One site is above permafrost while the other, 13 m away in an area of weak groundwater discharge, has no underlying permafrost. At the permafrost site, temperatures at the surface of the dry, porous organic mat experienced large diurnal variation but temperature amplitude was strongly attenuated with depth. Steep thermal gradients induce diffusion of water vapor from the base of the active layer toward the surface. Evaporative cooling thus inhibits heat penetration and maintains subfreezing temperatures at depth. However, infiltration of precipitation is an effective method of transporting sensible heat to the base of the active layer and extending seasonal thaw depth above permafrost. Conversely, at the groundwater seep site, saturation maintained by throughflow damps temperature variation with time and depth, and precipitation has little impact on the evolution of the thermal regime. Soil conditions and precipitation patterns strongly influence the nonconductive heat flux component and produce complex spatial and temporal thaw patterns.

  3. Recent ice cap snowmelt in Russian High Arctic and anti-correlation with late summer sea ice extent

    NASA Astrophysics Data System (ADS)

    Zhao, Meng; Ramage, Joan; Semmens, Kathryn; Obleitner, Friedrich

    2014-04-01

    Glacier surface melt dynamics throughout Novaya Zemlya (NovZ) and Severnaya Zemlya (SevZ) serve as a good indicator of ice mass ablation and regional climate change in the Russian High Arctic. Here we report trends of surface melt onset date (MOD) and total melt days (TMD) by combining multiple resolution-enhanced active and passive microwave satellite datasets and analyze the TMD correlations with local temperature and regional sea ice extent. The glacier surface snowpack on SevZ melted significantly earlier (-7.3 days/decade) from 1992 to 2012 and significantly longer (7.7 days/decade) from 1995 to 2011. NovZ experienced large interannual variability in MOD, but its annual mean TMD increased. The snowpack melt on NovZ is more sensitive to temperature fluctuations than SevZ in recent decades. After ruling out the regional temperature influence using partial correlation analysis, the TMD on both archipelagoes is statistically anti-correlated with regional late summer sea ice extent, linking land ice snowmelt dynamics to regional sea ice extent variations.

  4. Late Summer Booklist.

    ERIC Educational Resources Information Center

    Heins, Ethel L.; And Others

    1980-01-01

    Lists and annotates new books for children, arranged according to the following categories: picture books; stories for younger, for intermediate, and for older readers; folklore and legends; poetry and songs; and nonfiction. Also annotates a book about folktales that is of interest to adults. (GT)

  5. Late Summer Booklist.

    ERIC Educational Resources Information Center

    And Others; Heins, Ethel L.

    1979-01-01

    Lists and annotates new books for children, arranged according to the following categories: picture books; stories for younger, for intermediate, and for older readers; folklore and legends; poetry; and nonfiction. (GT)

  6. The Impact of Enhanced Summer Thaw, Hillslope Disturbances, and Late Season Rainfall on Solute Fluxes from High Arctic Headwater Catchments

    NASA Astrophysics Data System (ADS)

    Lafreniere, M. J.; Lamoureux, S. F.

    2011-12-01

    This study examines variations in the composition and total seasonal fluxes of dissolved solutes in several small High Arctic headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut (74°54'N, 109°35'W) over multiple snowmelt seasons (2007, 2008, 2009) with contrasting climate and permafrost active layer conditions. Climate warming in the High Arctic will affect a number processes that will alter the hydrological and biogeochemical exports from the landscape. Climate change is projected to alter precipitation regimes, resulting in increases in both winter and summer precipitation in the High Arctic, thereby altering hydrological regimes. Warming will result in thickening of the seasonal active layer, which will alter hydrological flow paths and water and solute sources. Additionally, active layer thickening and permafrost warming is also project to enhance the development of thermokarst features, including hillslope disturbances, such as active layer detachment slides and retrogressive thaw slumps. This research compares the flux of inorganic and organic solutes emanating from a group of catchments that were subject to a range hillslope disturbances, or active layer detachment slides (ALDs), at the end of summer 2007. One of the catchments, Goose, was not subject to any disturbance, while active layer slides covered between 6% and 46% of the catchment area in the disturbed catchments. It was hypothesised that solute fluxes would increase primarily with increasing extent and degree of disturbance. This however, was not observed. Rather, comparing five sites with varying degrees of disturbance in 2009 illustrates that on a specific area and specific volume of runoff basis, solute fluxes were unrelated to disturbance extent. Comparing two catchments that were monitored from 2007 (pre-disturbance) through to 2009 (2 yrs post disturbance), shows that both catchments were subject to solute flux increases, however the solute

  7. Climate inferences between paleontological, geochemical, and geophysical proxies in Late Pleistocene lacustrine sediments from Summer Lake, Oregon, western Great Basin

    NASA Astrophysics Data System (ADS)

    Heaton, Eric; Thompson, Greg; Negrini, Rob; Wigand, Peter

    2016-04-01

    Paleontological, geochemical, and geophysical data from western Great Basin pluvial Summer Lake, Oregon have established a high resolution paleoclimate record during the late Pleistocene Mono Lake Excursion (~34.75 ka), Dansgaard-Oeschger interstadials 6-8, and the end of Heinrich Even 4 (~38 ka). Proxies of grain-size, magnetic susceptibility, carbon/nitrogen ratio, ostracode analysis and palynology from a depocenter core show new results with improved age control regarding high amplitude, high frequency changes in lake level, lake temperature, and regional precipitation and temperature which correspond directly with colder/warmer and respectively drier/wetter climates as documented with Northern Atlantic Greenland ice core data. Results from geophysical and geochemical analysis, and the presence of ostracode Cytherissa lacustris consistently demonstrate the correspondence of low lake conditions and colder water temperatures during Dansgaard-Oeschger stadials and the Mono Lake Excursion. The opposite holds true during interstadials. Smaller grain size, increases in carbon/nitrogen ratio and consistent absence of C. lacustris suggest periods of increased discharge into the lake, increased lake level, and warmer water temperatures. Warmer/wetter climate conditions are confirmed during interstadials 7 and 8 from pollen analysis. Existence of Atriplex, Rosaceae, Chrysothamnus and Ambrosia, and pollen ratios of Juniperus/Dip Pinus and (Rosaceae+Atriplex+Poaceae+Chrysothamnus+Ambrosia)/(Pinus+Picea+T. mertensiana+Sarcobatus) suggest warmer/wetter semi-arid woodland conditions during interstadials 7 and 8. This contrasts with absences in these pollens and pollen ratios indicating colder/drier continental montane woodland conditions during stadials and the Mono Lake Excursion. Increases in Juniper/Dip Pinus ratio suggest a warmer/wetter climate during interstadial 6 however additional proxies do not demonstrate comparative warmer/wetter climate, deeper lake level or

  8. Interdecadal changes on the seasonal prediction of the western North Pacific summer climate around the late 1970s and early 1990s

    NASA Astrophysics Data System (ADS)

    Li, Chaofan; Lu, Riyu; Dong, Buwen

    2016-04-01

    Identifying predictability and the corresponding sources for the western North Pacific (WNP) summer climate in the case of non-stationary teleconnections during recent decades benefits for further improvements of long-range prediction on the WNP and East Asian summers. In the past few decades, pronounced increases on the summer sea surface temperature (SST) and associated interannual variability are observed over the tropical Indian Ocean and eastern Pacific around the late 1970s and over the Maritime Continent and western-central Pacific around the early 1990s. These increases are associated with significant enhancements of the interannual variability for the lower-tropospheric wind over the WNP. In this study, we further assess interdecadal changes on the seasonal prediction of the WNP summer anomalies, using May-start retrospective forecasts from the ENSEMBLES multi-model project in the period 1960-2005. It is found that prediction of the WNP summer anomalies exhibits an interdecadal shift with higher prediction skills since the late 1970s, particularly after the early 1990s. Improvements of the prediction skills for SSTs after the late 1970s are mainly found around tropical Indian Ocean and the WNP. The better prediction of the WNP after the late 1970s may arise mainly from the improvement of the SST prediction around the tropical eastern Indian Ocean. The close teleconnections between the tropical eastern Indian Ocean and WNP summer variability work both in the model predictions and observations. After the early 1990s, on the other hand, the improvements are detected mainly around the South China Sea and Philippines for the lower-tropospheric zonal wind and precipitation anomalies, associating with a better description of the SST anomalies around the Maritime Continent. A dipole SST pattern over the Maritime Continent and the central equatorial Pacific Ocean is closely related to the WNP summer anomalies after the early 1990s. This teleconnection mode is quite

  9. The Asian summer monsoon: an intercomparison of CMIP5 vs. CMIP3 simulations of the late 20th century

    NASA Astrophysics Data System (ADS)

    Sperber, K. R.; Annamalai, H.; Kang, I.-S.; Kitoh, A.; Moise, A.; Turner, A.; Wang, B.; Zhou, T.

    2013-11-01

    The boreal summer Asian monsoon has been evaluated in 25 Coupled Model Intercomparison Project-5 (CMIP5) and 22 CMIP3 GCM simulations of the late twentieth Century. Diagnostics and skill metrics have been calculated to assess the time-mean, climatological annual cycle, interannual variability, and intraseasonal variability. Progress has been made in modeling these aspects of the monsoon, though there is no single model that best represents all of these aspects of the monsoon. The CMIP5 multi-model mean (MMM) is more skillful than the CMIP3 MMM for all diagnostics in terms of the skill of simulating pattern correlations with respect to observations. Additionally, for rainfall/convection the MMM outperforms the individual models for the time mean, the interannual variability of the East Asian monsoon, and intraseasonal variability. The pattern correlation of the time (pentad) of monsoon peak and withdrawal is better simulated than that of monsoon onset. The onset of the monsoon over India is typically too late in the models. The extension of the monsoon over eastern China, Korea, and Japan is underestimated, while it is overestimated over the subtropical western/central Pacific Ocean. The anti-correlation between anomalies of all-India rainfall and Niño3.4 sea surface temperature is overly strong in CMIP3 and typically too weak in CMIP5. For both the ENSO-monsoon teleconnection and the East Asian zonal wind-rainfall teleconnection, the MMM interannual rainfall anomalies are weak compared to observations. Though simulation of intraseasonal variability remains problematic, several models show improved skill at representing the northward propagation of convection and the development of the tilted band of convection that extends from India to the equatorial west Pacific. The MMM also well represents the space-time evolution of intraseasonal outgoing longwave radiation anomalies. Caution is necessary when using GPCP and CMAP rainfall to validate (1) the time

  10. The summer 2012 Saharan dust season in the western Mediterranean with focus on the intense event of late June during the Pre-ChArMEx campaign

    NASA Astrophysics Data System (ADS)

    Dulac, François; Nicolas, José B.; Sciare, Jean; Mallet, Marc; Léon, Jean-François; Pont, Véronique; Sicard, Michaël; Renard, Jean-Baptiste; Nabat, Pierre; El Amraoui, Laaziz; Jaumouillé, Elodie; Roberts, Greg; Attié, Jean-Luc; Somot, Samuel; Laurent, Benoît; Losno, Rémi; Vincent, Julie; Formenti, Paola; Bergametti, Gilles; Ravetta, François

    2013-04-01

    Saharan dust is an usual aerosol over the Mediterranean basin that contributes to the high average aerosol load during summer in the western Mediterranean marine environment. Satellite monitoring shows that dust events were numerous during summer 2012. Even though most of the transport of dust particles occurs in altitude, as shown by surface lidars and airborne data, dust events significantly impact surface PM10 concentrations even in urban traffic type of air quality monitoring stations, and background stations are needed to assess the contribution of desert dust. During the pre-ChArMEx field campaign and associated field campaigns TRAQA and VESSAER in the north-western Mediterranean, a large scale African dust event occurred in late June-early July with optical depth levels in the visible up to 0.5-0.7 rather unusual in that area according to long time remote sensing AERONET or satellite series. We have performed measurements in the dust plume for several days with a particularly large variety of both ground-based and airborne (from sounding balloons, an aircraft and an ultra-light aircraft) remote sensing and in situ instruments. In addition to satellite aerosol products including MSG/SEVIRI, which provides the spatial distribution of the aerosol optical depth over the basin up to 4 times per hour, POLDER and CALIOP, this yields a complete set of unusual quantitative constraints for model simulations of this event, combining data on aerosol optical depth, vertical distribution, particle size distribution, chemical, optical and microphysical properties. We shall provide an overview of the data set that includes original measurements of the vertical profile of the aerosol size distribution with a new small balloon borne OPC called LOAC (Light Optical Aerosol Counter) showing large dust particles (up to 30 µm in diameter) within a thick dust layer between 1 and 5 km above south-eastern France, and original network measurement of weekly dust deposition with a new

  11. Coupling the Mars Dust and Water Cycles: Investigating the Role of Clouds in Controlling the Vertical Distribution of Dust During N. H. Summer

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Wilson, R. J.

    2014-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere (Gierasch and Goody, 1968; Haberle et al., 1982; Zurek et al., 1992). Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer (Smith, 2004). Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across (Cantor et al., 2001). During some years, regional storms combine to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by as much as 40 K (Smith et al., 2002). Key recent observations of the vertical distribution of dust indicate that elevated layers of dust exist in the tropics and sub-tropics throughout much of the year (Heavens et al., 2011). These observations have brought particular focus on the processes that control the vertical distribution of dust in the Martian atmosphere. The goal of this work is to further our understanding of how clouds in particular control the vertical distribution of dust, particularly during N. H. spring and summer

  12. Predicted Impacts of Conjunctive Water Management Scenarios on Late Summer Streamflow in an Agricultural Groundwater Basin with Limited Storage, Scott Valley, CA.

    NASA Astrophysics Data System (ADS)

    Tolley, D. G., III; Foglia, L.; Harter, T.

    2015-12-01

    Late summer streamflow for the Scott River in northern California has decreased approximately 50% since the mid 1960's, resulting in increased water temperatures and disconnection of the stream. This negatively impacts aquatic habitat of fish species such as coho and fall-run Chinook salmon. In collaboration with local stakeholders, the Scott Valley Integrated Hydrologic Model has been developed, which combines a water budget model and a groundwater-surface water model (MODFLOW) of the 200 km2 basin. The goal of the integrated model is to better understand the hydrologic system of the valley and explore effects of different conjunctive management scenarios on late summer streamflow. The groundwater model has a 100 m lateral resolution with aggregated monthly stresses over a 21 year simulation period (1990-2011). The Scott River and tributaries are represented using the streamflow routing (SFR) package. A sensitivity analysis and calibration were performed by hand using 812 head observations from 50 wells in the basin and average daily streamflow observations from a USGS stream gauge during the simulation period. The calibrated model was used to evaluate two different management scenarios: 1) in-lieu recharge where surface-water instead of groundwater is used to irrigate fields near the river while streamflow is sufficiently high, and 2) managed aquifer recharge during the winter months on agricultural fields located in gulches on the eastern side of the valley using existing infrastructure. Preliminary results indicate that implementation of conjunctive water management may increase late summer streamflow at the gauging station by 1-2 cubic feet per second (cfs), a significant amount given that flows are around 10-20 cfs during this time. This increase in flow during the late summer decreases the length of dry reaches both spatially and temporally, allowing for earlier reconnection of the Scott River and decreased stress on fish.

  13. Dike orientations in the late jurassic independence dike swarm and implications for vertical-axis tectonic rotations in eastern California

    USGS Publications Warehouse

    Hopson, R.F.; Hillhouse, J.W.; Howard, K.A.

    2008-01-01

    Analysis of the strikes of 3841 dikes in 47 domains in the 500-km-long Late Jurassic Independence dike swarm indicates a distribution that is skewed clockwise from the dominant northwest strike. Independence dike swarm azimuths tend to cluster near 325?? ?? 30??, consistent with initial subparallel intrusion along much of the swarm. Dike azimuths in a quarter of the domains vary widely from the dominant trend. In domains in the essentially unrotated Sierra Nevada block, mean dike azimuths range mostly between 300?? and 320??, with the exception of Mount Goddard (247??). Mean dike azimuths in domains in the Basin and Range Province in the Argus, Inyo, and White Mountains areas range from 291?? to 354?? the mean is 004?? in the El Paso Mountains. In the Mojave Desert, mean dike azimuths range from 318?? to 023??, and in the eastern Transverse Ranges, they range from 316?? to 051??. Restoration for late Cenozoic vertical-axis rotations, suggested by paleodeclinations determined from published studies from nearby Miocene and younger rocks, shifts dike azimuths into better agreement with azimuths measured in the tectonically stable Sierra Nevada. This confirms that vertical-axis tectonic rotations explain some of the dispersion in orientation, especially in the Mojave Desert and eastern Transverse Ranges, and that the dike orientations can be a useful if imperfect guide to tectonic rotations where paleomagnetic data do not exist. Large deviations from the main trend of the swarm may reflect (1) clockwise rotations for which there is no paleomagnetic evidence available, (2) dike intrusions of other ages, (3) crack filling at angles oblique or perpendicular to the main swarm, (4) pre-Miocene rotations, or (5) unrecognized domain boundaries between dike localities and sites with paleomagnetic determinations. ?? 2008 The Geological Society of America.

  14. Unexpected consequences of a drier world: evidence that delay in late summer rains biases the population sex ratio of an insect.

    PubMed

    Bonal, Raul; Hernández, Marisa; Espelta, Josep M; Muñoz, Alberto; Aparicio, José M

    2015-09-01

    The complexity of animal life histories makes it difficult to predict the consequences of climate change on their populations. In this paper, we show, for the first time, that longer summer drought episodes, such as those predicted for the dry Mediterranean region under climate change, may bias insect population sex ratio. Many Mediterranean organisms, like the weevil Curculio elephas, become active again after summer drought. This insect depends on late summer rainfall to soften the soil and allow adult emergence from their underground refuges. We found that, as in many protandric species, more C. elephas females emerged later in the season. Male emergence timing was on average earlier and also more dependent on the beginning of late summer rainfall. When these rains were delayed, the observed weevil sex ratio was biased towards females. So far, the effects of global warming on animal sex ratios has been reported for temperature-dependent sex determination in reptiles. Our results show that rainfall timing can also bias the sex ratio in an insect, and highlight the need for keeping a phenological perspective to predict the consequences of climate change. We must consider not just the magnitude of the predicted changes in temperature and rainfall but also the effects of their timing. PMID:26473046

  15. Vertical displacement during late-collisional escape tectonics (Brasiliano Orogeny) in the Ribeira Belt, São Paulo State, Brazil

    NASA Astrophysics Data System (ADS)

    Hackspacher, P. C.; Godoy, A. M.

    1999-07-01

    During the Brasiliano-Pan-African Orogeny, West Gondwana formed by collisional processes around the São Francisco-Congo Craton. The Ribeira belt, in southeastern Brazil, resulted from northwestward collision (650-600 Ma), followed by large-scale northeast-southwest dextral strike-slip shear movements related to late-collisional escape tectonics ( ca 600 Ma). In São Paulo State, three groups, also interpreted as terranes, are recognised in the Ribeira Belt, the Embu, Itapira and São Roque Groups. The Embu and Itapira Groups are formed of sillimanite-gneisses, schists and migmatites intruded by Neoproterozoic calc-alkaline granitoids, all thrusted northwestward. The São Roque Group is composed of metasediments and metavolcanics in greenschist-facies. Its deformation indicates a transpressional regime associated with tectonic escape. Sub-alkaline granites were emplaced in shallow levels during this regime. Microstructural studies along the Itu, Moreiras and Taxaquara Shear Zones demonstrate the coexistence of horizontal and vertical displacement components during the transpressional regime. The vertical component is regarded as responsible for the lateral juxtaposition of different crustal levels.

  16. Late Neogene evolution of the East Asian monsoon revealed by terrestrial mollusk record in Western Chinese Loess Plateau: From winter to summer dominated sub-regime

    NASA Astrophysics Data System (ADS)

    Li, Fengjiang; Rousseau, Denis-Didier; Wu, Naiqin; Hao, Qingzhen; Pei, Yunpeng

    2008-10-01

    More and more evidence indicates that the onset of the East Asian (EA) monsoon can be traced back to the Oligocene-Miocene boundary (at about 23 Ma). However, the process of its evolution is still less well-known until now. Here we investigate its late Neogene evolution by analyzing a terrestrial mollusk sequence, from the Chinese Loess Plateau (CLP), covering the period between 7.1 and 3.5 Ma. Considering the modern ecological requirements of these organisms, we were able to define two groups of cold-aridiphilous (CA) and thermo-humidiphilous (TH) species, representing the EA winter and summer monsoon variations, respectively, as previously defined in the Quaternary glacial-interglacial cycles. Variations in these two groups indicate two different monsoon dominated periods during 7.1-3.5 Ma. First, between 7.1 and 5.5 Ma, the EA winter monsoon, with a 100-kyr periodicity, was dominant. Second, between 5.1 and 4 Ma, the EA summer monsoon dominated, with a 41-kyr periodicity. Furthermore, our mollusk record yields valuable evidence for a late Miocene-Pliocene transition of about 400 kyr from winter monsoon dominated towards summer monsoon dominated, associated with a periodicity transition from weak 100 kyr to 41 kyr. The strengthened winter monsoon interval, with a 100-kyr periodicity, is coeval with orbital-scale global ice-volume changes, in conjunction with the uplift of the Tibetan Plateau which probably reinforced the winter monsoon sub-regime. Conversely, closures of the Panama and Indonesian seaways, associated with changes in obliquity between 5.1 and 4 Ma, are probably major forcing factors for the observed dominant summer monsoon with 41-kyr frequency, favoring heat and moisture transports between low and high latitudes to allow TH mollusks to grow and develop in the CLP.

  17. Radiative energy budget estimates for the 1979 southwest summer monsoon

    NASA Technical Reports Server (NTRS)

    Ackerman, Steven A.; Cox, Stephen K.

    1987-01-01

    A major objective of the summer monsoon experiment (SMONEX) was the determination of the heat sources and sinks associated with the southwest summer monsoon. The radiative component is presented here. The vertically integrated tropospheric radiation energy budget is negative and varies significantly as a function of monsoon activity. The gradient in the latitudinal mean tropospheric cooling reverses between the winter periods and the late spring/early summer periods. The radiative component of the vertical profile of the diabatic heating is derived. These profiles are a strong function of the stage of the monsoon as well as the geographic region. In general, the surface experiences a net gain of radiative energy during the late spring and early summer periods. During the winter periods, areas northward of 25 N display net surface losses, while the remaining areas exhibit net gains.

  18. Inferences about winter temperatures and summer rains from the late Quaternary record of C4 perennial grasses and C3 desert shrubs in the northern Chihuahuan Desert

    USGS Publications Warehouse

    Holmgren, Camille A.; Norris, Jodi; Betancourt, Julio L.

    2007-01-01

    Late Quaternary histories of two North American desert biomes—C4 grasslands and C3 shrublands—are poorly known despite their sensitivity and potential value in reconstructing summer rains and winter temperatures. Plant macrofossil assemblages from packrat midden series in the northern Chihuahuan Desert show that C4 grasses and annuals typical of desert grassland persisted near their present northern limits throughout the last glacial-interglacial cycle. By contrast, key C3 desert shrubs appeared somewhat abruptly after 5000cal.yrBP. Bioclimatic envelopes for select C4 and C3 species are mapped to interpret the glacial-interglacial persistence of desert grassland and the mid-to-late Holocene expansion of desert shrublands. The envelopes suggest relatively warm Pleistocene temperatures with moist summers allowed for persistence of C4 grasses, whereas winters were probably too cold (or too wet) for C3 desert shrubs. Contrary to climate model results, core processes associated with the North American Monsoon and moisture transport to the northern Chihuahuan Desert remained intact throughout the last glacial-interglacial cycle. Mid-latitude effects, however, truncated midsummer (July-August) moisture transport north of 35° N. The sudden expansion of desert shrublands after 5000cal.yrBP may be a threshold response to warmer winters associated with increasing boreal winter insolation, and enhanced El Niño-Southern Oscillation variability.

  19. [MAX-DOAS measurements of NO2 column densities and vertical distribution at Ny-Alesund, Arctic during summer].

    PubMed

    Luo, Yu-Han; Sun, Li-Guang; Liu, Wen-Qing; Xie, Pin-Hua; Si, Fu-Qi; Zhou, Hai-Jin

    2012-09-01

    The multi-axis differential optical absorption spectroscopy (MAX-DOAS), one of the remote sensing techniques for trace gases measurements, is sensitive to the lower atmosphere by eliminating the influence of stratosphere retrieved from zenith-sky spectroscopy. Ground-based MAX-DOAS measurements were carried out to observe NO2 at Ny-Alesund, Arctic from 5th Jul to 1st Aug 2011. The differential slant column densities (DSCDs) of NO2 at four off-axis angles showed typical pattern of tropospheric absorbers. Based on the assumption that NO2 was well mixed in 0-1 km of the troposphere, the mean mixing ratio of NO2 during the measurement period was 1.023E11 molec x cm(-3). The fluctuation of NO2 might be related to the fossil fuel combustions and the photochemical reactions. The vertical distribution of NO2 at 0-3 km showed that NO2 was mainly originated from boundary layer of sea surface. PMID:23240391

  20. Vertical structure of cumulonimbus towers and intense convective clouds over the South Asian region during the summer monsoon season

    NASA Astrophysics Data System (ADS)

    Bhat, G. S.; Kumar, Shailendra

    2015-03-01

    The vertical structure of radar reflectivity factor in active convective clouds that form during the South Asian monsoon season is reported using the 2A25 version 6 data product derived from the precipitation radar measurements on board the Tropical Rainfall Measuring Mission satellite. We define two types of convective cells, namely, cumulonimbus towers (CbTs) and intense convective cells (ICCs). CbT is defined referring to a reflectivity threshold of 20 dBZ at 12 km altitude and is at least 9 km thick. ICCs are constructed referring to reflectivity thresholds at 8 km and 3 km altitudes. Cloud properties reported here are based on 10 year climatology. It is observed that the frequency of occurrence of CbTs is highest over the foothills of Himalayas, plains of northern India and Bangladesh, and minimum over the Arabian Sea and equatorial Indian Ocean west of 90°E. The regional differences depend on the reference height selected, namely, small in the case of CbTs and prominent in 6-13 km height range for ICCs. Land cells are more intense than the oceanic ones for convective cells defined using the reflectivity threshold at 3 km, whereas land versus ocean contrasts are not observed in the case of CbTs. Compared to cumulonimbus clouds elsewhere in the tropics, the South Asian counterparts have higher reflectivity values above 11 km altitude.

  1. Late Pleistocene C4 plant dominance and summer rainfall in the southwestern United States from isotopic study of herbivore teeth

    USGS Publications Warehouse

    Connin, S.L.; Betancourt, J.; Quade, Jay

    1998-01-01

    Patterns of climate and C4 plant abundance in the southwestern United States during the last glaciation were evaluated from isotopic study of herbivore tooth enamel. Enamel ??13C values revealed a substantial eastward increase in C4 plant consumption for Mammuthus spp., Bison spp., Equus spp., and Camelops spp. The ??13C values were greatest in Bison spp. (-6.9 to + 1.7???) and Mammuthus spp. (-9.0 to +0.3???), and in some locales indicated C4-dominated grazing. The ??13C values of Antilocaprids were lowest among taxa (-12.5 to -7.9???) and indicated C3 feeding at all sites. On the basis of modern correlations between climate and C4 grass abundance, the enamel data imply significant summer rain in parts of southern Arizona and New Mexico throughout the last glaciation. Enamel ??18O values range from +19.0 to +31.0??? and generally increase to the east. This pattern could point to a tropical or subtropical source of summer rainfall. At a synoptic scale, the isotope data indicate that interactions of seasonal moisture, temperature, and lowered atmospheric pCO2 determined glacial-age C4 abundance patterns.

  2. Late Neogene East Asian monsoon: from winter to summer dominated sub-regime and periodicity transition from 100 kyr to 41 kyr

    NASA Astrophysics Data System (ADS)

    Li, F.; Rousseau, D.-D.; Wu, N.; Hao, Q.; Pei, Y.

    2009-04-01

    More and more evidence indicates that the onset of the East Asian (EA) monsoon can be traced back to the Oligocene-Miocene boundary (at about 23 Ma). However, the process of its evolution is still less well known until now. Here we investigate its late Neogene evolution by analyzing a terrestrial mollusk sequence, from the Chinese Loess Plateau (CLP), covering the period between 7.1 and 3.5 Ma. Considering the modern ecological requirements of these organisms, we were able to define two groups of cold-aridiphilous (CA) and thermo-humidiphilous (TH) species, representing the EA winter and summer monsoon variations, respectively, as previously defined in the Quaternary glacial-interglacial cycles. Variations in these two groups indicate two different monsoon dominated periods during 7.1-3.5 Ma. First, between 7.1 and 5.5 Ma, the EA winter monsoon, with a 100 kyr periodicity, was dominant. Second, between 5.1 and 4 Ma, the EA summer monsoon dominated, with a 41 kyr periodicity. Furthermore, our mollusk record yields valuable evidence for a late Miocene-Pliocene transition of about 400 kyr from winter monsoon dominated towards summer monsoon dominated, associated with a periodicity transition from weak 100 kyr to 41 kyr. The strengthened winter monsoon interval, with a 100 kyr periodicity, is coeval with orbital-scale global ice volume changes, in conjunction with the uplift of the Tibetan Plateau which probably reinforced the winter monsoon sub-regime. Conversely, closures of the Panama and Indonesian seaways, associated with changes in obliquity between 5.1 and 4 Ma, are probably major forcing factors for the observed dominant summer monsoon with 41 kyr frequency, favoring heat and moisture transports between low and high latitudes to allow TH mollusks to grow and develop in the CLP. The transition from a 100 kyr dominated interval towards a 41 kyr dominated one is contrary to the mid-Pleistocene transition (MPT), which corresponds to ice volume expansion at high

  3. Booktalking: Avoiding Summer Drift

    ERIC Educational Resources Information Center

    Whittingham, Jeff; Rickman, Wendy A.

    2015-01-01

    Summer drift, otherwise known as loss of reading comprehension skills or reading achievement, has been a well-known and well-documented phenomenon of public education for decades. Studies from the late twentieth century to the present have demonstrated a slowdown in summer drift attributed to specific summer reading programs addressing motivation…

  4. Descriptions of the Animas River-Cement Creek confluence and mixing zone near Silverton, Colorado, during the late summers of 1996 and 1997

    USGS Publications Warehouse

    Schemel, Laurence E.; Cox, Marisa H.

    2005-01-01

    Acidic waters from Cement Creek discharge into the circum-neutral Animas River in a high-elevation region of the San Juan Mountains near Silverton, Colorado. Cement Creek is acidic and enriched in metals and sulfate because it is fed by discharges from abandoned mines and natural mineral deposits. Mixing with the Animas River raises the pH and produces precipitates of iron and aluminum (oxy)hydroxides, which in turn can adsorb other metals. This confluence was studied in 1996 and 1997 to better understand mixing and sorption processes which are common during the neutralization of acidic streams. The photographs in this report show flow braiding and other features that influenced the way the two streams mixed during the late summers of the two years. They also show 'banding' due to incomplete mixing and 'opalescence' due to chemical reactions and the formation of colloidal-size particles in the mixing zone.

  5. Late summer and fall use of stream margins by young-of year brown trout in a high-elevation stream

    USGS Publications Warehouse

    La Voie, W. J., IV; Hubert, W.A.

    1997-01-01

    We determined the relative abundance of young-of-year (YOY) brown trout (Salmo trutta) from late summer to fall during day and night in stream margin habitats of Douglas Creek, Wyoming. No significant differences in relative abundance were observed from August 14 through October 26. Few YOY brown trout were observed during the day over the entire sampling period, but significantly greater numbers were seen at night. Within stream margins, YOY brown trout of 36-75 mm total length primarily resided in concealment cover among interstices of cobbie during the day and emerged at night. Because no significant change in relative abundance was observed throughout the study period, we conclude that a shift to winter habitat did not occur up until three days prior to ice formation when the diurnal range in water temperature was 2.5-7.5??C.

  6. The distribution of bioluminescence and chlorophyll during the late summer in the North Atlantic: Maps and a predictive model

    NASA Astrophysics Data System (ADS)

    Ondercin, Daniel G.; Atkinson, Charles A.; Kiefer, Dale A.

    1995-04-01

    During August 1991 an instrument array (the Paravane) was towed continuously for several days over long distances in the North Atlantic and around the Marine Light-Mixed Layer (MLML) mooring (60°N, 21°W). Among other sensors, the Paravane carried a thermistor, a fluorometer that measured the fluorescence emitted by chlorophyll a, a bathyphotometer that measured stimulable bioluminescence, and a beam transmissometer that measured the volume attenuation coefficient at 490 nm. The record of these biooptical measurements provides a detailed description of the upper 150 m of the water column as well as of diel variability. An examination of the transects, which covered a latitudinal range from 43°N to 60°N and a longitudinal range from 13°W to 54°W, indicates that in the colder and more northerly waters most of the chlorophyll a, attenuation, and bioluminescence were found within the surface mixed layer. In the warmer waters to the south, there were subsurface maxima for all three parameters. We have used the Paravane records to test a model that provides predictions of the vertical distribution of chlorophyll a, bioluminescence, and beam attenuation from oceanographie parameters that characterize the surface mixed layer: temperature, chlorophyll a concentration, irradiance incident to the sea surface, mixed layer depth, and nitrate concentration. The first three parameters can be measured from sensors aboard satellites while the last two parameters can be obtained from oceanographie databases. The model is based upon a description of the acclimation of the phytoplankton, an assumption about the vertical distribution of phytoplankton within the euphotic zone, and an empirical description of the relationship between bioluminescence, light intensity, and phytoplankton concentration.

  7. Shift in principal equilibrium current from a vertical to a toroidal one towards the initiation of a closed flux surface in ECR plasmas in the LATE device

    NASA Astrophysics Data System (ADS)

    Kuroda, Kengoh; Wada, Manato; Uchida, Masaki; Tanaka, Hitoshi; Maekawa, Takashi

    2016-02-01

    In toroidal electron cyclotron resonance (ECR) plasmas under a weak external vertical field {{B}\\text{V}} a part of the pressure driven vertical charge separation current returns along the helical field lines, generating a toroidal current. The rest circulates via the conducting vacuum vessel. Only the toroidal current contributes to the production of a closed flux surface. Both the toroidal and vertical currents are an equilibrium current that provides a radial force by the interaction with the vertical field and the toroidal field, respectively, to counter-balance the outward pressure ballooning force. We have done experiments using 2.45 GHz microwaves in the low aspect ratio torus experiment (LATE) device to investigate in what way and how much the toroidal current is generated towards the initiation of a closed flux surface. In steady discharges by {{P}\\text{inj}}=1.5 kW under various {{B}\\text{V}} both the pressure and the toroidal current become large with {{B}\\text{V}} . When {{B}\\text{V}}=6.8 G, a toroidal current of 290 A is generated and the vertical field is reduced to 1.2 G inside the current channel, being close to the initiation of a closed flux surface. In this plasma the return current does not obey Ohm’s law. Instead, the return current flows so that the electric force on the electron fluid is balanced with the pressure gradient along the field lines. Near the top and bottom boundaries superthermal electrons flow beyond the potential barrier onto the walls along the field lines. In another discharge by the low power of {{P}\\text{inj}}=1.0 kW under {{B}\\text{V}}=8.3 G, both the toroidal current and the pressure steadily increase for an initial duration of 1.1 s and then abruptly jump, generating an initial closed flux surface. While the counter force from the vertical current is initially dominant, that from the toroidal current gradually increases and becomes four times larger than that from the vertical current just before the initiation

  8. Late-summer mass deposition of gelatinous phytodetritus along the slope of the N.W. European Continental Margin

    NASA Astrophysics Data System (ADS)

    de Wilde, P. A. W. J.; Duineveld, G. C. A.; Berghuis, E. M.; Lavaleye, M. S. S.; Kok, A.

    1998-12-01

    In the period 1993-1995 the OMEX area has been visited 3 times to address the question of across-slope transport of suspended matter from the shelf to the deep sea. By analyzing phytopigments and nucleic acids in the sediment and water of the N.W. European Continental slope and rise seasonal patterns of benthic food input were investigated and relation between input and the structure and activity of the benthic community were explored. Chloropigments in the surface sediments indicated that a spring bloom effect could be traced down to about 2500 m. During late August 1995 heavy deposits of gelatinous matter, characterized by high concentrations of chloropigments and nucleic acids, were detected all over the ocean floor of the outer slope and continental rise below 3500 m. It is estimated that this mucus layer had a carbon load of 250 mmol C m -2 over an area of 50,000 km 2. The recent state of the mucus allowed us to search for its origin. Characteristic pigment composition and the presence of coccoliths pointed to prymnesiophytes (coccolithophorids) as a major contributor, but dinoflagellates (peridinin) and green algae (chlorophyll-b, lutein) must have contributed as well. Simultaneous observations of the overlying water column, deep chlorophyll maximum, revealed the presence of a coccolithophorid bloom in a recent stage of disintegration at St. III. An obvious relation with the mucus carpet, however, could not be indicated. This, and the significant differences in pigment composition and pigment ratios at the various deep stations lead us to understand that the extended mucus field at the Celtic slope originates from different, more or less synoptically occurring surface blooms. The presence of large `vacuum-cleaning' sea-cucumbers is considered indicative of the occurrence of phytodetritus pulses.

  9. Late Holocene South American and Indian summer monsoon variability: Assessing the regional significance of the Medieval Climate Anomaly and Little Ice Age

    NASA Astrophysics Data System (ADS)

    Bird, B. W.; Rudloff, O. M.; Escobar, J.; Polissar, P. J.; Steinman, B. A.; Thompson, L. G.; Yao, T.

    2014-12-01

    The response of Earth's major climate systems to natural forcings during the last 2000 years can provide valuable insight into the affect that ongoing climate change may have on these systems. Understanding the relationship between temperature, monsoonal hydroclimate and radiative forcing is of particular interest because hydrologic responses in these systems have the ability to impact over half of the global population. Here, late Holocene variability in the South American and Indian summer monsoon regions is examined using sedimentological, geochemical and isotopic proxies from high altitude lake sediment archives from the Colombian Andes and the southeastern Tibetan Plateau. New results from Laguna de Ubaque, a small moraine dammed lake at 2060 m ASL in the Eastern Cordillera of the Colombian Andes, suggest a reduction in Andean South American summer monsoon (SASM) rainfall during the Medieval Climate Anomaly (MCA; 900 to 1200 CE) that is consistent with other records from the Andes. During the Little Ice Age (LIA; 1450 to 1900 CE), Ubaque shows wet conditions between 1450 and 1600 CE and drier conditions from1600 to 1900 CE. This pattern is similar to accumulation at the Quelccaya Ice Cap, but differs from ice core, speleothem and lake sediment oxygen isotope records of synoptic-scale monsoonal precipitation, suggesting that Andean rainfall anomalies may have differed from upstream monsoonal trends over the Amazon. In contrast, results from Badi Namco and Paru Co on the southeastern Tibetan Plateau suggest that the MCA and LIA were relatively minor hydroclimate events superimposed on a larger millennial scale variation in Indian summer monsoon precipitation (1200 to 200 cal yr B.P.) that was associated with changes in the position of the ITCZ, surface air temperature over the Tibetan Plateau and sea surface temperatures in the western tropical Pacific. The unique hydroclimate variations in the ISM and SASM regions supports the idea that while spatially

  10. Carbonate leaching processes in the Red Clay Formation, Chinese Loess Plateau: Fingerprinting East Asian summer monsoon variability during the late Miocene and Pliocene

    NASA Astrophysics Data System (ADS)

    He, Tong; Chen, Yang; Balsam, William; Qiang, Xiaoke; Liu, Lianwen; Chen, Jun; Ji, Junfeng

    2013-01-01

    High-resolution variations in carbonate minerals from the Jiaxian Red Clay section, located at the northern limit of the present East Asian summer monsoon (EASM) on Chinese Loess Plateau were quantified using Fourier transform infrared spectroscopy. We analyzed a large quantity of sediments dated from the late Miocene to Pliocene (8.2-2.6 Ma). The carbonates in this interval show high-frequency variations alternating between leached and calcareous horizons. The low carbonate contents and high values of magnetic susceptibility and high Rb/Sr ratios were found in the leached zones, a pattern that is consistent with that observed in the overlying Quaternary loess-paleosol sequences. This pattern suggests that East Asian Monsoon (EAM) rainwater enhanced leaching and accumulation processes of carbonate minerals in the Red Clay Formation in a way similar to the loess-paleosol sequence. Seven alternating leached and calcareous zones are identified, suggesting oscillations of the EASM and East Asian winter monsoon intervals. The calcareous zones were also found to have high Zr/Rb ratio. These indications of shifts from a strong EASM to East Asian winter monsoon dominance correlate well with the cooling transition indicated by deep sea δ18O isotopes. This evidence suggests that the EAM was active during the late Miocene and Pliocene and was similar to the Quaternary monsoon. The presence of a strong EAM during the Pliocene Warm Period also raises questions about the hypothesis that past and future warm climate conditions could produce a permanent El Niño-like state.

  11. Short scale variations in nutrients, ectoenzymatic activities and bottom-up effects on bacterial production and community structure during late summer-autumn transition in the open NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    van Wambeke, F.; Ghiglione, J.-F.; Nedoma, J.; Mével, G.; Raimbault, P.

    2009-01-01

    We examined the vertical and temporal dynamics of nutrients, ectoenzymatic activities under late summer-fall transition period (September-October 2004) in NW Mediterranean Sea in relation to temporal change in factors limiting bacterial production. The depth of the mixed layer (12.8±5.3 m) was extremely stable until the onset of the destratification period after 11 October, creating a zone where diffusion of nutrient from the much deeper phosphacline (69±12 m) and nitracline (50±8 m) was probably strongly limited. However during the second half of the cruise, a shallowing of nutriclines occured, particularly marked for nitracline. Hence, the nitrate to phosphate ratio within the mixed layer, although submitted to a high short term variability, shifted the last week of the cruise from 1.1±1.2 to 4.6±3.8, and nitrate increased by a factor 2 (0.092±0.049 μM). A corresponding switch from more than one limitation (PN) to P-only limitation of bacterial production was observed during the month as detected by enrichment bioassays. Differences in the identity of the limiting nutrient in surface (5 m: N and P at the beginning, strictly P at the end of the study) versus 80 m (labile carbon) influence greatly bacterial community structure shift between these two layers. The two communities (5 and 80 m) reacted rapidly (24 h) to changes in nutrient concentrations by drastic modification of total and active population assemblages resulting in changes in activity. For bacterial production values less than 10 ng C l-1h-1 (associated to deeper layers), aminopeptidase and lipase exhibited higher activity relative to production whereas phosphatase varied in the same proportions than BP on the range of activities tested. Our results illustrate the effect of bottom-up control on bacterial community structure and activities in the epipelagic NW Mediterranean Sea.

  12. The role of biophysical indicators in the reconstruction of long-term late-spring - summer temperatures for the region of Western Hungary and Eastern Austria

    NASA Astrophysics Data System (ADS)

    Kiss, Andrea; Wilson, Rob; Holawe, Franz; Strömmer, Elisabeth; Bariska, István.

    2010-05-01

    , Sopron and Bratislava series and all presented analyses were developed within the framework of the EU project 'Millenium'. The Austrian series are partly based on published series (Pribram 1938, Lauscher 1985, Strömmer 2003) although in some cases modified and extended for this study, as well as newly developed data. The present work is a continuation of the 'Analysis of late spring-summer temperatures for Western Hungary based on vine, grain tithes and harvest records', presented at the annual congress of EGU in 2009 (Kiss and Wilson 2009). References Böhm, R., Jones, P.D., Hiebl, J., Frank, D., Brunetti, M., Maugeri and M. 2009: The early instrumental warm-bias: a solution for long central European temperature series 1760-2007. Climatic Change, doi: 10.1007/s10584-009-9649-4. Kiss, A. and Wilson, R. 2009: Analysis of late spring-summer temperatures for Western Hungary based on vine, grain tithes and harvest records. Geophysical Research Abstracts Vol 11, EGU2009-10945-1. Lauscher, F. 1985: Beiträge zur Wetterchronik seit dem Mittelalter. In: Sitzungsberichte, Abtheilung II, Mathematische, Physikalische und Technische Wissenschaften, Band 194, Heft 1-3. pp. 93-131. Leijonhufvud, L., Wilson, R., Möberg, A., Söderberg, J., Retső, D. and Söderlind, U. 2009: Five centuries of Stockholm winter/spring temperatures reconstructed from documentary evidence and instrumental observations. Climatic Change, doi: 10.1007/s10584-009-9650-y. Pribram, A. F. 1938: Materialien zur Geschichte der Preise und Löhne in Österreich. Band. I. Carl Ueberreuters Verlag, Wien. pp. 364-370. Strömmer, E. 2003: Klima-Geschichte. Methoden der Rekonstruction und historische Perspektive. Ostösterreich 1700 bis 1830. Forschungen und Beiträge zur Wiener Stadtgescichte 39. Franz Deuticke, Wien. pp. 59-71.

  13. Inconsistent Climate Inferences between Pollen and other Paleontological, Geochemical, and Geophysical Proxies in Late Pleistocene Lacustrine Sediments from Summer Lake, Oregon, Western Great Basin

    NASA Astrophysics Data System (ADS)

    Heaton, E.; Thompson, G.; Negrini, R. M.; Wigand, P. E.

    2015-12-01

    This study has established a high resolution paleoclimate record from western Great Basin pluvial Summer Lake, Oregon during the late Pleistocene Mono Lake Excursion (~34 ka), Dansgaard-Oeschger (D-O) interstadials 7 and 8, and the end of Heinrich Even 4 (~38 ka). Proxies of grain-size, carbon/nitrogen (C/N) ratio, ostracode analysis and palynology from a depocenter core show new results regarding high amplitude, high frequency changes in lake level, precipitation and temperature which correspond directly with colder/warmer and respectively drier/wetter climates as documented with Northern Atlantic Greenland ice core data. The granulometry, geochemical, and ostracode results consistently demonstrate the correspondence of low lake conditions and colder water temperatures during D-O stadials and warmer/wetter climate during interstadials. These results are contradicted by the pollen results. Existence of cold temperature spores Botrychium and Selaginella coincide with increases in Artemisia, Atriplex, Sarcobatus, Cyperaceae and decreases in Pinus, also suggesting periods of colder/drier climate and shallower lake levels but the timing does not match that of those conditions inferred by the other methods. Granulometry, geochemical, and ostracode proxies denote cold periods and low lake levels roughly between 37.5-35.6 ka and 34.6-33.8 ka. Pollen analysis suggests near-opposite time intervals with cold periods roughly 38-37.5 ka, 35.6-35 ka. This pollen inconsistency suggests the possibility of (1) a millennial-scale lag response of vegetation to climate change, (2) runoff from stadial precipitation causing influx in pollen abundances and variety found in the depocenter core, or (3) turbulent mixing from shallow lake level causing resuspension and redeposition of pollen (Bradley 1999).

  14. Late Quaternary depositional history, Holocene sea-level changes, and vertical crustal movement, southern San Francisco Bay, California

    USGS Publications Warehouse

    Atwater, Brian F.; Hedel, Charles W.; Helley, Edward J.

    1977-01-01

    Sediments collected for bridge foundation studies at southern San Francisco Bay, Calif., record estuaries that formed during Sangamon (100,000 years ago) and post-Wisconsin (less than 10,000 years ago) high stands of sea level. The estuarine deposits of Sangamon and post-Wisconsin ages are separated by alluvial and eolian deposits and by erosional unconformities and surfaces of nondeposition, features that indicate lowered base levels and oceanward migrations of the shoreline accompanying low stands of the sea. Estuarine deposits of mid-Wisconsin age appear to be absent, suggesting that sea level was not near its present height 30,000–40,000 years ago in central California. Holocene sea-level changes are measured from the elevations and apparent 14C ages of plant remains from 13 core samples. Uncertainties of ±2 to ±4 m in the elevations of the dated sea levels represent the sum of errors in determination of (1) sample elevation relative to present sea level, (2) sample elevation relative to sea level at the time of accumulation of the dated material, and (3) postdepositional subsidence of the sample due to compaction of underlying sediments. Sea level in the vicinity of southern San Francisco Bay rose about 2 cm/yr from 9,500 to 8,000 years ago. The rate of relative sea-level rise then declined about tenfold from 8,000 to 6,000 years ago, and it has averaged 0.1–0.2 cm/yr from 6,000 years ago to the present. This submergence history indicates that the rising sea entered the Golden Gate 10,000–11,000 years ago and spread across land areas as rapidly as 30 m/yr until 8,000 years ago. Subsequent shoreline changes were more gradual because of the decrease in rate of sea-level rise. Some of the sediments under southern San Francisco Bay appear to be below the level at which they initially accumulated. The vertical crustal movement suggested by these sediments may be summarized as follows: (1) Some Quaternary(?) sediments have sustained at least 100 m of

  15. The role of vertical land movements on late 19th century sea level rise at Cuxhaven, Germany

    NASA Astrophysics Data System (ADS)

    Niehüser, Sebastian; Jensen, Jürgen; Wahl, Thomas; Dangendorf, Sönke; Hofstede, Jacobus

    2015-04-01

    Tide gauges, located along the world's coastlines, represent one of the most important data sources with information about sea level change back into the 17th century, bridging the gap between paleo proxies and modern remote sensing data sources. While the worldwide coverage of tide gauges has increased considerably since the mid-20th century, there are only a few gauges available providing information about regional sea level changes before 1900. Furthermore, these tide gauge measurements are often contaminated by local vertical land movements (VLM) resulting from tectonic processes or local anthropogenic interventions. Such non-climatic effects need to be removed from the raw data to uncover climate signals, which are important, for instance, for answering the question whether and when sea level started to accelerate from the nearly constant rates over the past 2000 years. Here we focus on one of these long tide gauge records: Cuxhaven, which is located in the German Bight and provides uninterrupted digital time series of tidal high and low water levels since 1843. The record has been extensively studied during the past decades with respect to regional and global sea level rise. However, a question that still remains is the role of local subsidence before 1900 at the lighthouse of Cuxhaven, located close to the tide gauge. In 1855 Lentz installed a granite height mark at the lighthouse, which was later used as a proxy for VLMs of the tide gauge itself. The height of the control mark was derived by a levelling between Hamburg and Cuxhaven. These levellings were repeated five times between 1855 and 1900 and later evaluated by Siefert and Lassen (1985) with respect to the role of local subsidence. Based on a linear regression of individual levellings Siefert and Lassen (1985) concluded that the lighthouse subsided by an average rate of 2.8 mm/yr (1855-1875: 4.2 mm/yr; 1876-1890: 2 mm/yr; 1890-1900: 1.2 mm/yr). However, due to the massive uncertainties of these early

  16. Preliminary Vertical Slip Rate for the West Tahoe Fault from six new Cosmogenic 10Be Exposure Ages of Late Pleistocene Glacial Moraines at Cascade Lake, Lake Tahoe, California

    NASA Astrophysics Data System (ADS)

    Pierce, I. K. D.; Wesnousky, S. G.; Kent, G. M.; Owen, L. A.

    2015-12-01

    The West Tahoe Fault is the primary range bounding fault of the Sierra Nevada at the latitude of Lake Tahoe. It is a N-NW striking, east dipping normal fault that has a pronounced onshore quaternary scarp extending from highway 50 southwest of Meyers, CA to Emerald Bay. At Cascade Lake, the fault cuts and progressively offsets late Pleistocene right lateral moraines. The fault vertically offsets the previously mapped Tahoe moraine ~83 m and the Tioga moraine ~23 m, measured from lidar data. Seventeen samples were collected for 10Be cosmogenic age analysis from boulders on both the hanging and footwalls of the fault along the crests of these moraines.We report here the initial analysis of 6 of these boulders and currently await processing of the remainder. The 10Be exposure ages of 3 boulders each on the younger Tioga and older Tahoe moraines range from 12.7 +/- 1.6 to 20.7 +/- 3.3 ka and 13.3 +/- 2.1 to 72.5 +/- 8.8 ka, respectively. Using the oldest ages as minima, these preliminary results suggest that the slip rate has averaged ~1 mm/yr since the penultimate glaciation, in accord with estimates of previous workers, and place additional bounds on the age of glaciation in the Lake Tahoe basin. The Last Glacial Maxima and penultimate glaciation near Lake Tahoe thus appear to coincide with the Tioga and Tahoe II glaciations of the Eastern Sierra.

  17. High resolution satellite microwave record of Russian High Arctic snowmelt timing, duration, and relation to late summer sea ice extent (Invited)

    NASA Astrophysics Data System (ADS)

    Ramage, J. M.; Zhao, M.; Semmens, K. A.; Obleitner, F.

    2013-12-01

    and passive microwave satellite data, and analyze the TMD correlations with local temperature and regional sea ice extent. MOD for the icecaps is defined as the first day when more than 90% of ice-covered pixels start melting and is derived from multiple sensors between 1992 and 2012. Total TMD are the cumulative number of days that experienced melt days over the entire year, including short-lived events before or after the main melt season. The glacier surface snowpack on SevZ melted significantly earlier (-7.3 days/decade) from 1992 to 2012 and significantly longer (7.7 days/decade) from 1995 to 2011. NovZ experienced large interannual variability in MOD, but its annual mean TMD increased. The snowpack melt on NovZ is more sensitive to temperature fluctuations than SevZ in recent decades. The TMD on both archipelagoes is statistically anti-correlated with regional late summer sea ice extent, linking land ice melt dynamics to regional sea ice extent variations.

  18. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    NASA Astrophysics Data System (ADS)

    Yao, Fengchao; Hoteit, Ibrahim; Pratt, Larry J.; Bower, Amy S.; Zhai, Ping; Köhl, Armin; Gopalakrishnan, Ganesh

    2014-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  19. Composition and distribution of planktonic ciliates in the southern South China Sea during late summer: Comparison between surface and 75 m deep layer

    NASA Astrophysics Data System (ADS)

    Liu, Huaxue; Shen, Pingping; Li, Chunhou; Chen, Zuozhi; Qi, Zhanhui; Huang, Honghui

    2016-02-01

    Ciliates are very important components in most marine ecosystem. They are trophic link between the microbial food web and grazing food chain. In this study, ciliates were collected from 11 sites in the southern South China Sea (SCS) during August 25 to September 28, 2011. Their composition and distribution at the surface and 75 m deep depth of the ocean were studied. A total of 30 species belonging to 22 genera were identified, and 22 species of 15 genera were Tintinnids. Eutintinnus fraknoii and E. stramentus were the most common species. The other dominants were strombidiids ciliates including Strombidium conicum and S. globosaneum, which were followed by the tide form, Mesodinium pulex. Ciliates abundance ranged from 46 ind L-1 to 368 ind L-1 in the open sites, 46-368 ind L-1 at surface and 73-198 ind L-1 at 75 m deep layer. In the Yongshu reef, ciliates abundance ranged from 167 ind L-1 to 365 ind L-1 in the water column, similar to that in Sanya coral reef waters. Ciliates composition showed obvious difference between surface and 75 m deep layer at station S2 ( P < 0.05), while no similar result was observed at other sites. At 75 m deep layer, salinity was negatively related to mixed layer depth ( P < 0.05), but positively to chlorophyll a concentration ( P < 0.05), indicating that the change of vertical mixing in water column influenced vertical distribution of ciliates in the southern SCS.

  20. Multi-scale, multi-year investigations of H2O ice deposits observed in late summer, at the time of minimum extent of the Southern polar cap of Mars

    NASA Astrophysics Data System (ADS)

    Langevin, Y.; Seelos, K.; Russell, P.; Bibring, J.-P.; Vincendon, M.; Gondet, B.

    2012-09-01

    Extended regions exhibiting water ice signatures have been observed by OMEGA on Mars Express at the boundary of the CO2 perennial cap during the first months of operation of the mission [1]. This period in late summer (Ls 335°-340°) corresponds to the minimum extent of the ice coverage around the South pole. The retreat of the South seasonal cap, spectrally dominated by CO2 frost [2, 3] ends at Ls 310° - 315° for years which do not present a global dust storm [4], and the first signs of H2O frost recondensation are observed before the fall equinox (Ls 0°). A large outlier had been identified by OMEGA observations at longitudes from 290°E to 10°E. It was shown to extend over an area representing ~ 25% of the surface of the perennial cap by Themis observations [5]. The H2O covered regions at the boundary of the cap and within the outlier have an intermediate albedo (30-35%) between that of the perennial cap (> 60%) and that of surrounding terrains (~ 20%). These southern surface H2O ice deposits constitute a major source of atmospheric H2O at the end of the Southern summer. They are much smaller in extent than the northern perennial cap and they are exposed to sunlight for 2 months in late summer instead of 6 months in the North over the whole summer. This is in line with the highly asymmetric seasonal cycle of atmospheric water [6, 7]. In late 2009, OMEGA observations of the South cap at the time of minimum extent (Ls 340°) showed a much larger extent of H2O ice signatures compared to what had been observed in early 2004 [1]. H2O ice covered regions appeared homogeneous at the km scales corresponding to OMEGA observations. A series of CRISM observations were planned for the next southern fall season (mid-2011), in order to further investigate the time variability of the southern H2O ice deposits within the outlier at the 20 m scale (CRISM high resolution mode). Combining OMEGA and CRISM observations demonstrates that variegation of surface H2O ice is mainly

  1. Signals of the South China Sea summer rainfall variability in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    He, Zhuoqi; Wu, Renguang; Wang, Weiqiang

    2016-05-01

    The present study investigates signals of the South China Sea (SCS) summer rainfall variability in the Indian Ocean. It is found that the SCS summer rainfall has a negative relationship with December-January-February (DJF) western-equatorial Indian Ocean (WIO) sea surface temperature (SST), a positive relationship with an asymmetric mode of precipitation anomalies in the tropical Indian Ocean during March-April-May (MAM), and a positive relationship with June-July-August (JJA) South Indian Ocean (SIO) SST. The WIO SST anomalies induce same-sign southeast Indian Ocean SST anomalies through an anomalous zonal vertical circulation. The southeast Indian Ocean SST anomalies last from late winter to early summer and induce opposite-sign SCS summer rainfall anomalies via an anomalous meridional vertical circulation. The asymmetric mode influences the SCS summer rainfall variation via the North Indian Ocean (NIO) SST anomalies with significant cloud-radiation and wind-evaporation effect. Positive (negative) SIO SST anomalies drive an anomalous direct circulation between the SIO and the NIO, and an anomalous indirect circulation between the NIO and the SCS which facilitates the occurrence of cyclonic (anti-cyclonic) wind anomalies over the SCS-western North Pacific and results in positive (negative) SCS summer rainfall anomalies. Partial correlation analysis indicates that the influence of DJF WIO SST anomalies and JJA SIO SST anomalies on the SCS summer rainfall is partly ENSO-independent, while the MAM asymmetric mode is mostly related to the preceding DJF eastern Pacific SST anomalies.

  2. Non-serotinous woody plants behave as aerial seed bank species when a late-summer wildfire coincides with a mast year

    PubMed Central

    Pounden, Edith; Greene, David F; Michaletz, Sean T

    2014-01-01

    Abstract Trees which lack obvious fire-adaptive traits such as serotinous seed-bearing structures or vegetative resprouting are assumed to be at a dramatic disadvantage in recolonization via sexual recruitment after fire, because seed dispersal is invariably quite constrained. We propose an alternative strategy in masting tree species with woody cones or cone-like structures: that the large clusters of woody tissue in a mast year will sufficiently impede heat transfer that a small fraction of seeds can survive the flaming front passage; in a mast year, this small fraction would be a very large absolute number. In Kootenay National Park in British Columbia, we examined regeneration by Engelmann spruce (Picea engelmannii), a non-serotinous conifer, after two fires, both of which coincided with mast years. Coupling models of seed survivorship within cones and seed maturation schedule to a spatially realistic recruitment model, we show that (1) the spatial pattern of seedlings on a 630 m transect from the forest edge into the burn was best explained if there was in situ seed dissemination by burnt trees; (2) in areas several hundred meters from any living trees, recruitment density was well correlated with local prefire cone density; and (3) spruce was responding exactly like its serotinous codominant, lodgepole pine (Pinus contorta). We conclude that non-serotinous species can indeed behave like aerial seed bank species in mast years if the fire takes place late in the seed maturation period. Using the example of the circumpolar boreal forest, while the joint probability of a mast year and a late-season fire will make this type of event rare (we estimate P = 0.1), nonetheless, it would permit a species lacking obvious fire-adapted traits to occasionally establish a widespread and abundant cohort on a large part of the landscape. PMID:25614797

  3. Spatial variability of the species composition, abundance, and productivity of the phytoplankton in the white sea in the late summer period

    NASA Astrophysics Data System (ADS)

    Ilyash, L. V.; Radchenko, I. G.; Kuznetsov, L. L.; Lisitzyn, A. P.; Martynova, D. M.; Novigatskiy, A. N.; Chul'Tsova, A. L.

    2011-02-01

    The species composition, cell concentration ( N), and biomass ( B) of the phytoplankton, as well as the chlorophyll a (Chl a) concentration, primary production ( PP), and the concentrations of the dissolved inorganic micronutrients (phosphorus, silica, nitrogen as nitrite), were estimated for Kandalaksha Bay (KB), Dvina Bay (DB), and the basin (Bas) of the White Sea in August of 2004. The micronutrient concentrations were lower compared to the average long-term values for the summer period. The Chl a concentration varies from 0.9 to 2.0 mg/m3 for most of the studied areas, reaching up to 7.5 mg/m3 in the Northern Dvina River estuary. The surface water layer of the DB was the most productive area, where the PP reached up to 270-375 mg C/(m3 day). The phytoplankton biomass varied from 11 to 205 mg C/m3 with the highest values observed in the Bas and DB. Three groups of stations were defined during the analysis of the phytoplankton's species composition similarity. The dinoflagellates Dinophysis norvegica and Ceratium fusus were particular to the phytoplankton assemblages in the KB; the diatom Ditylum brightwellii was particular to the upper and central parts of the DB. These three phytoplankton species were less abundant in the Bas.

  4. Vertical air mass exchange driven by the local circulation on the northern slope of Mount Everest

    NASA Astrophysics Data System (ADS)

    Zhou, Libo; Zou, Han; Ma, Shupo; Li, Peng; Zhu, Jinhuan; Huo, Cuiping

    2011-01-01

    To better understand vertical air mass exchange driven by local circulation in the Himalayas, the volume flux of air mass is estimated in the Rongbuk Valley on the northern slope of Mount Everest, based on a volume closure method and wind-profiler measurements during the HEST2006 campaign in June 2006. Vertical air mass exchange was found to be dominated by a strong downward mass transfer from the late morning to late night. The average vertical air volume flux was 0.09 m s-1, which could be equivalent to a daily ventilation of 30 times the enclosed valley volume. This vertical air mass exchange process was greatly affected by the evolution of the South Asian summer monsoon (SASM), with a strong downward transfer during the SASM break stage, and a weak transfer during the SASM active stage.

  5. Summer Learners.

    ERIC Educational Resources Information Center

    Harrington-Lueker, Donna

    2000-01-01

    Many urban districts are sending thousands of poorly performing students to summer school to boost achievement. Boston, New York City, and other districts are finding summer school a costly, complicated intervention that does not always show immediate results or resolve social-promotion problems. Implementation strategies are outlined. (MLH)

  6. Summer Astronomy

    ERIC Educational Resources Information Center

    Riddle, Bob

    2004-01-01

    This brief article describes what can be expected of the skies in the summer of 2004 with quite a few celestial thrills to anticipate. In addition to the planet viewing opportunities, there is a very rare Venus transit of the Sun and the annual Perseid meteor shower. The 2004 summer also marks both an end and beginning for the Cassini/Huygens…

  7. Late-summer zooplankton community structure, abundance, and distribution in the Hudson Bay system (Canada) and their relationships with environmental conditions, 2003-2006

    NASA Astrophysics Data System (ADS)

    Estrada, Rafael; Harvey, Michel; Gosselin, Michel; Starr, Michel; Galbraith, Peter S.; Straneo, Fiammetta

    2012-08-01

    weakly stratified Arctic-North Atlantic waters coming from southwestern Davis Strait (inflow). In general, the RDA models tested among the HBS regions were very consistent with its general surface circulation pattern for summer conditions in terms of environmental variables and distinct zooplankton assemblages. Overall, zooplankton biomass and diversity indices (H‧, J‧, and S) were lower in the most stratified environment (i.e., HB) than in the deeper (FB) and more dynamic (HS) regions. The results of this work clearly show that the spatial differentiation and structure of the zooplankton communities are strongly influenced by the hydrodynamic conditions in the HBS that, trough their actions on temperature, salinity, stratification, mixing conditions and depth strata, lead to the spatial differentiation of these communities.

  8. Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines.

    PubMed

    Cryan, Paul M; Jameson, Joel W; Baerwald, Erin F; Willis, Craig K R; Barclay, Robert M R; Snider, E Apple; Crichton, Elizabeth G

    2012-01-01

    Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines. PMID:23094065

  9. Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines

    USGS Publications Warehouse

    Cryan, P.M.; Jameson, J.W.; Baerwald, E.F.; Willis, C.K.R.; Barclay, R.M.R.; Snider, E.A.; Crichton, E.G.

    2012-01-01

    Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

  10. Evidence of Late-Summer Mating Readiness and Early Sexual Maturation in Migratory Tree-Roosting Bats Found Dead at Wind Turbines

    PubMed Central

    Cryan, Paul M.; Jameson, Joel W.; Baerwald, Erin F.; Willis, Craig K. R.; Barclay, Robert M. R.; Snider, E. Apple; Crichton, Elizabeth G.

    2012-01-01

    Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines. PMID:23094065

  11. Evidence for Late Devonian vertical movements and extensional deformation in northern Africa and Arabia: Integration in the geodynamics of the Devonian world

    NASA Astrophysics Data System (ADS)

    Frizon de Lamotte, Dominique; Tavakoli-Shirazi, Saeid; Leturmy, Pascale; Averbuch, Olivier; Mouchot, Nicolas; Raulin, Camille; Leparmentier, FrançOis; Blanpied, Christian; Ringenbach, Jean-Claude

    2013-03-01

    The Upper Paleozoic geodynamic evolution is discussed at the scale of a wide part of Gondwana from North Africa to Arabia. With the aim of giving an integrated tectonic scenario for the study domain, we revisit six key areas, namely, the Anti-Atlas Belt (Morocco), the Bechar Basin (west Algeria), the Hassi R'Mel High (central Algeria), the Talemezane Arch (south Tunisia), the Western Desert (Egypt), and, finally, the High Zagros Belt (Iran). Below the so-called "Hercynian unconformity," which is in reality a highly composite discontinuity, surface and subsurface data display a well-known arch-and-basin geometry, with basement highs and intervening Paleozoic basins. We show that this major feature results mainly from a Late Devonian event and can no longer be interpreted as a far effect of the Variscan Orogeny. This event is characterized by a more or less diffuse extensional deformation and accompanied either by subsidence, in the western part of the system, or by an important uplift of probable thermal origin followed by erosion and peneplanation. By the end of the Devonian, the whole region suffered a general subsidence governed by the progressive cooling of the lithosphere. Such a primary configuration is preserved in Arabia with typical sag geometry of the Carboniferous and Permian deposits but strongly disturbed elsewhere by the conjugated effects of the Variscan Orogeny during the Carboniferous and/or by subsequent uplifts linked to the central Atlantic and Neo-Tethys rifting episodes. In conclusion, we try to integrate this new understanding in the geodynamics of the Late Devonian, which at world scale is characterized by the onset of the Variscan Orogeny on the one hand and by magmatism, rifting, and basement uplift on the other hand.

  12. Late-summer Martian Dust Storm

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an image of Mars taken from orbit by the Mars Reconnaissance Orbiter's Mars Color Imager (MARCI). The Red Planet's polar ice-cap is in the middle of the image. Captured in this image is a 37,000 square-kilometer (almost 23,000 miles) dust storm that moved counter-clockwise through the Phoenix landing site on Oct 11, 2008, or Sol 135 of the mission.

    Viewing this image as if it were the face of a clock, Phoenix is shown as a small white dot, located at about 10 AM. The storm, which had already passed over the landing site earlier in the day, is located at about 9:30 AM.

  13. Fish distribution studies near N Reactor, Summer 1983

    SciTech Connect

    Dauble, D.D.; Page, T.L.

    1984-06-01

    This report summarizes field studies that were initiated in July 1983 to provide estimates of the relative distribution of late-summer outmigrant juvenile salmonids and juvenile resident fish upstream of the N Reactor 009 Outfall. Chinook salmon are among the fish species most sensitive to thermal effects, and impacts to the juvenile outmigrant populations are of particular concern to state and federal regulatory and fisheries management agencies. Therefore, the distribution studies were conducted from late July through September, a period when high ambient river temperatures and low river flows make these salmonid populations most susceptible to thermal effects. In addition, data were not available on the spatial distribution of outmigrant juvenile chinook salmon in late summer. Information on the relative distribution of resident fish populations was also gathered. Previous studies of midstream distribution of juvenile resident fish were limited to a description of ichthyoplankton populations (Beak Consultants, Inc. 1980 Page et al. 1982), and no data were available on vertical or horizontal distribution of juvenile resident fish species near N Reactor. Relative densities and spatial distribution estimates of juvenile salmonid and resident fish species will be used in conjunction with laboratory thermal effects studies (Neitzel et al. 1984) and with plume characterization studies (Ecker et al. 1983) to assess potential impacts of thermal discharge on fish populations near N Reactor.

  14. Summer Journal.

    ERIC Educational Resources Information Center

    Evansville-Vanderburgh School Corp., IN.

    This student activity book is intended for junior high or high school students. Originally written to be used in a summer television course, the material can be adapted to a regular class situation. The wide variety of materials are relevant to courses in reading, literature, composition, speech, psychology, and social studies. The book includes…

  15. Summer Skies

    ERIC Educational Resources Information Center

    Science Scope, 2005

    2005-01-01

    During the evening hours of the summer of 2005, there will be numerous opportunities to observe several of the brighter planets as they move along their respective orbits, overtaking and passing one another, performing a planetary dance with the choreography set to orbital speeds. With the exception of Mars, the visible planets will all be in the…

  16. Summer Programs.

    ERIC Educational Resources Information Center

    Toussaint, Isabella H.

    An intensive 6-week summer readiness program held in the Beaver Area School District, Beaver, Pennsylvania, developed linguistic facility among 15 preschool children. Daily activities included discussion, picture study, creative arts, field trips, developing experience charts, and other nonlanguage arts activities. A combined experiential,…

  17. Reconstructing the Late Pleistocene Southern Ocean biological pump using the vertical gradient of Cd/Ca in planktic and benthic foraminifera

    NASA Astrophysics Data System (ADS)

    Charidemou, Miros; Hall, Ian; Ziegler, Martin

    2015-04-01

    The Southern Ocean is a particularly important region in the global carbon cycle because its wind-driven upwelling regime brings CO2-rich deep waters to the ocean surface. However, outgassing of CO2 to the atmosphere is ultimately determined by the efficiency of the soft-tissue biological pump which transfers carbon back into the deep sea. Biological productivity in the Southern Ocean on glacial-interglacial timescales is thought to be influenced by the availability of iron from terrestrial dust sources (Martin, 1990). However, the exact nature of the relationship between productivity and dust flux is still debated (Ziegler et al., 2013; Martinez-Garcia et al., 2014) and remains unclear for earlier times such as during the Middle Pleistocene Transition (MPT). Changes in the strength of the soft-tissue biological pump can be reconstructed with relative ease by measuring carbon isotopes in planktic and benthic foraminifera and quantifying the vertical gradient between them (Ziegler et al., 2013). Our ultimate aim is to use this technique to reconstruct changes in the biological pump in the Southern Ocean during the MPT, when a sharp rise in dust flux is observed in the sedimentary record (Martinez-Garcia et al., 2011). This will allow us to assess the contribution of changes in the Southern Ocean biological pump to the climatic reorganisation that occurred during the MPT. However, before the Δδ13C record is constructed for the MPT it is vital to confirm that this method is indeed a reliable proxy for the soft-tissue biological pump. Records of Δδ13C can be influenced by changes in the whole ocean inventory of δ13C, changes in circulation and changes in the degree of fractionation between the ocean and the atmosphere. The impact of inventory and circulation changes can be minimised by careful selection of study sites and by targeting foraminifera that live within specific water masses. However, deviations of Δδ13C from the biological signal could certainly

  18. Decapod crustacean larval communities in the Balearic Sea (western Mediterranean): Seasonal composition, horizontal and vertical distribution patterns

    NASA Astrophysics Data System (ADS)

    Torres, Asvin P.; Dos Santos, Antonina; Balbín, Rosa; Alemany, Francisco; Massutí, Enric; Reglero, Patricia

    2014-10-01

    Decapod crustaceans are the main target species of deep water bottom trawl fisheries in the Balearic Sea but little is known about their larval stages. This work focuses on the species composition of the decapod larval community, describing the main spatio-temporal assemblages and assessing their vertical distribution. Mesozooplankton sampling was carried out using depth-stratified sampling devices at two stations located over the shelf break and the mid slope, in the north-western and southern Mallorca in late autumn 2009 and summer 2010. Differences among decapod larvae communities, in terms of composition, adult's habitat such as pelagic or benthic, and distribution patterns were observed between seasons, areas and station. Results showed that for both seasons most species and developmental stages aggregated within the upper water column (above 75 m depth) and showed higher biodiversity in summer compared to late autumn. Most abundant species were pelagic prawns (e.g., Sergestidae) occurring in both seasons and areas. The larval assemblages' distributions were different between seasonal hydrographic scenarios and during situations of stratified and non-stratified water column. The vertical distribution patterns of different larval developmental stages in respect to the adult's habitat were analyzed in relation to environmental variables. Fluorescence had the highest explanatory power. Four clearly different vertical patterns were identified: two corresponding to late autumn, which were common for all the main larval groups and other two in summer, one corresponding to larvae of coastal benthic and the second to pelagic species larvae.

  19. Intensified impact of northern tropical Atlantic SST on tropical cyclogenesis frequency over the western North Pacific after the late 1980s

    NASA Astrophysics Data System (ADS)

    Cao, Xi; Chen, Shangfeng; Chen, Guanghua; Wu, Renguang

    2016-08-01

    Previous studies suggest that spring SST anomalies over the northern tropical Atlantic (NTA) affect the tropical cyclone (TC) activity over the western North Pacific (WNP) in the following summer and fall. The present study reveals that the connection between spring NTA SST and following summer-fall WNP TC genesis frequency is not stationary. The influence of spring NTA SST on following summer-fall WNP TC genesis frequency is weak and insignificant before, but strong and significant after, the late 1980s. Before the late 1980s, the NTA SST anomaly-induced SST anomalies in the tropical central Pacific are weak, and the response of atmospheric circulation over the WNP is not strong. As a result, the connection between spring NTA SST and following summer-fall WNP TC genesis frequency is insignificant in the former period. In contrast, after the late 1980s, NTA SST anomalies induce pronounced tropical central Pacific SST anomalies through an Atlantic-Pacific teleconnection. Tropical central Pacific SST anomalies further induce favorable conditions for WNP TC genesis, including vertical motion, mid-level relative humidity, and vertical zonal wind shear. Hence, the connection between NTA SST and WNP TC genesis frequency is significant in the recent period. Further analysis shows that the interdecadal change in the connection between spring NTA SST and following summer-fall WNP TC genesis frequency may be related to the climatological SST change over the NTA region.

  20. Indian Summer

    SciTech Connect

    Galindo, E.

    1997-08-01

    This paper focuses on preserving and strengthening two resources culturally and socially important to the Shoshone-Bannock Indian Tribe on the Fort Hall Reservation in Idaho; their young people and the Pacific-Northwest Salmon. After learning that salmon were not returning in significant numbers to ancestral fishing waters at headwater spawning sites, tribal youth wanted to know why. As a result, the Indian Summer project was conceived to give Shoshone-Bannock High School students the opportunity to develop hands-on, workable solutions to improve future Indian fishing and help make the river healthy again. The project goals were to increase the number of fry introduced into the streams, teach the Shoshone-Bannock students how to use scientific methodologies, and get students, parents, community members, and Indian and non-Indian mentors excited about learning. The students chose an egg incubation experiment to help increase self-sustaining, natural production of steelhead trout, and formulated and carried out a three step plan to increase the hatch-rate of steelhead trout in Idaho waters. With the help of local companies, governmental agencies, scientists, and mentors students have been able to meet their project goals, and at the same time, have learned how to use scientific methods to solve real life problems, how to return what they have used to the water and land, and how to have fun and enjoy life while learning.

  1. Predictability of Zimbabwe summer rainfall

    NASA Astrophysics Data System (ADS)

    Makarau, Amos; Jury, Mark R.

    1997-11-01

    Predictors of Zimbabwe summer rainfall are investigated with a view to improved long-range forecasts. Teleconnectivity is assessed in respect of sea-surface temperatures, the Southern Oscillation index, the Quasi-biennial Oscillation (QBO), outgoing longwave radiation (OLR) and wind. Spectral analyses of historical rainfall gives an indication of cycles in the range 2.3, 18 and 3.8 years, possibly associated with the QBO, the luni-solar tide and the El No-Southern Oscillation (ENSO), respectively. Pair-wise correlations are found between Zimbabwe summer rainfall and SST in the central Indian Ocean (r<-0.5) in austral spring. Below normal OLR values in September over southern Africa corresponds with good rains in the following summer. Rainfall-upper-wind correlations are optimum (r<-0.7) over the equatorial Atlantic in spring. Comparatively weak correlation with the QBO may also reflect biennial adjustment of monsoon and global ENSO teleconnections. Additional predictor variables are utilized and multivariate models are formulated for early and late summer rainfall and maize yield in Zimbabwe. The models use three to five predictors, are trained over a 22-year period and perform well in jack-knife skill tests. Summer rainfall forecasts with one season lead times are viable and could ameliorate hardship caused by drought.

  2. Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992

    NASA Technical Reports Server (NTRS)

    Emmons, Louisa K.; Reeves, John M.; Shindell, Drew T.; Dezafra, Robert L.

    1994-01-01

    Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio.

  3. Next Generation Summer School

    NASA Astrophysics Data System (ADS)

    Eugenia, Marcu

    2013-04-01

    On 21.06.2010 the "Next Generation" Summer School has opened the doors for its first students. They were introduced in the astronomy world by astronomical observations, astronomy and radio-astronomy lectures, laboratory projects meant to initiate them into modern radio astronomy and radio communications. The didactic programme was structure as fallowing: 1) Astronomical elements from the visible spectrum (lectures + practical projects) 2) Radio astronomy elements (lectures + practical projects) 3) Radio communication base (didactic- recreative games) The students and professors accommodation was at the Agroturistic Pension "Popasul Iancului" situated at 800m from the Marisel Observatory. First day (summer solstice day) began with a practical activity: determination of the meridian by measurements of the shadow (the direction of one vertical alignment, when it has the smallest length). The experiment is very instructive and interesting because combines notions of physics, spatial geometry and basic astronomy elements. Next day the activities took place in four stages: the students processed the experimental data obtained on first day (on sheets of millimetre paper they represented the length of the shadow alignments according the time), each team realised its own sun quadrant, point were given considering the design and functionality of these quadrant, the four teams had to mimic important constellations on carton boards with phosphorescent sticky stars and the students, accompanied by the professors took a hiking trip to the surroundings, marking the interest point coordinates, using a GPS to establish the geographical coronations and at the end of the day the students realised a small map of central Marisel area based on the GPS data. On the third day, the students were introduced to basic notions of radio astronomy, the principal categories of artificial Earth satellites: low orbit satellites (LEO), Medium orbit satellites (MEO) and geostationary satellites (GEO

  4. THE VERTICAL

    NASA Technical Reports Server (NTRS)

    Albert, Stephen L.; Spencer, Jeffrey B.

    1994-01-01

    'THE VERTICAL' computer keyboard is designed to address critical factors which contribute to Repetitive Motion Injuries (RMI) (including Carpal Tunnel Syndrome) in association with computer keyboard usage. This keyboard splits the standard QWERTY design into two halves and positions each half 90 degrees from the desk. In order to access a computer correctly. 'THE VERTICAL' requires users to position their bodies in optimal alignment with the keyboard. The orthopaedically neutral forearm position (with hands palms-in and thumbs-up) reduces nerve compression in the forearm. The vertically arranged keypad halves ameliorate onset occurrence of keyboard-associated RMI. By utilizing visually-reference mirrored mylar surfaces adjustable to the user's eye, the user is able to readily reference any key indicia (reversed) just as they would on a conventional keyboard. Transverse adjustability substantially reduces cumulative musculoskeletal discomfort in the shoulders. 'THE VERTICAL' eliminates the need for an exterior mouse by offering a convenient finger-accessible curser control while the hands remain in the vertically neutral position. The potential commercial application for 'THE VERTICAL' is enormous since the product can effect every person who uses a computer anywhere in the world. Employers and their insurance carriers are spending hundreds of millions of dollars per year as a result of RMI. This keyboard will reduce the risk.

  5. Summer Precipitation Patterns Alter Soil Moisture and Carbon Dynamics in a High Elevation Meadow

    NASA Astrophysics Data System (ADS)

    Arnold, C. L.; Berhe, A. A.; Ghezzehei, T. A.

    2014-12-01

    High elevation meadow ecosystems in the Sierra Nevada Mountains and beyond are expected to experience shifts in precipitation patterns over the coming century. While the majority of precipitation falls in the form of rain and snow during the winter months, smaller discrete precipitation events occur during the summer months. These events play an important role in regulating soil moisture dynamics, and biogeochemical cycling of essential elements, including carbon and nitrogen. Preliminary data from a large subalpine meadow in Yosemite National Park, shows a marked decrease in the number of June, July and August pulse events over the last 30 years and a shift toward more smaller events earlier in June and infrequent larger events in July and August. In order to better understand the overall impact these changes have on carbon cycling in meadow ecosystems, detailed studies of current ecosystem functioning is critical. The overall objective of this study is to clarify the spatial and temporal distribution of soil moisture and carbon dioxide fluxes in response to precipitation pulses extending from spring melt through late summer in dry vs. wet meadow sites at a high elevation ecosystem. We found that: (1) Vertical and horizontal heterogeneity in soil moisture is a function of the timing, amount and duration of summer convective precipitation pulse events; (2) The effect of summer convective precipitation pulse events on soil respiration is most heavily influenced by timing between events rather than the magnitude of each event, with more pronounced effects in dry rather than wet meadow locations.

  6. The annual cycle of vertical mixing and restratification in the Northern Gulf of Eilat/Aqaba (Red Sea) based on high temporal and vertical resolution observations

    NASA Astrophysics Data System (ADS)

    Carlson, Daniel F.; Fredj, Erick; Gildor, Hezi

    2014-02-01

    The stratification in the Northern Gulf of Eilat/Aqaba follows a well-known annual cycle of well-mixed conditions in winter, surface warming in spring and summer, maximum vertical temperature gradient in late summer, and erosion of stratification in fall. The strength and structure of the stratification influences the diverse coral reef ecosystem and also affects the strength of the semi-diurnal tidal currents. Long-term (13 months) moored thermistor data, combined with high temporal and vertical resolution density profiles in deep water, show that transitions from summer to fall and winter to spring/summer occur in unpredictable, pulses and are not slow and gradual, as previously deduced from monthly hydrographic measurements and numerical simulations forced by monthly climatologies. The cooling and deepening of the surface layer in fall is marked by a transition to large amplitude, semi-diurnal isotherm displacements in the stratified intermediate layer. Stratification is rebuilt in spring and summer by intermittent pulses of warm, buoyant water that can increase the upper 100-150 m by 2 °C that force surface waters down 100-150 m over a matter of days. The stratification also varies in response to short-lived eddies and diurnal motions during winter. Thus, the variability in the stratification exhibits strong depth and seasonal dependence and occurs over range of timescales: from tidal to seasonal. We show that monthly or weekly single-cast hydrographic data under-samples the variability of the stratification in the Gulf and we estimate the error associated with single-cast assessments of the stratification.

  7. Slithering into Summer

    ERIC Educational Resources Information Center

    Scott, Catherine; Matthews, Catherine

    2012-01-01

    The summer provides a unique opportunity for children to further their interests in science, especially science in the out-of-doors. Once school is out for the summer, there is seemingly unlimited time, with no strict curriculum guidelines to follow. For students with a passion for the out-of-doors, summer science camps and school-based summer…

  8. Slowing the Summer Slide

    ERIC Educational Resources Information Center

    Smith, Lorna

    2012-01-01

    Research shows that summer slide--the loss of learning over the summer break--is a huge contributor to the achievement gap between low-income students and their higher-income peers. In fact, some researchers have concluded that two-thirds of the 9th-grade reading achievement gap can be explained by unequal access to summer learning opportunities…

  9. Summer Programs for Educators

    ERIC Educational Resources Information Center

    Curriculum Review, 2009

    2009-01-01

    There are so many great ways to extend oneself professionally--or personally--over the summer. This paper presents several opportunities for summer 2009: (1) The Teacher-to-Teacher Initiative; (2) Courage to Teach; (3) University of South Carolina's Summer Institute in Computer Science; (4) Online Program in Online Teaching; and (5) College Board…

  10. Summer Library Reading Programs

    ERIC Educational Resources Information Center

    Fiore, Carole D.

    2007-01-01

    Virtually all public libraries in the United States provide some type of summer library reading program during the traditional summer vacation period. Summer library reading programs provide opportunities for students of many ages and abilities to practice their reading skills and maintain skills that are developed during the school year. Fiore…

  11. Summer School: Unfulfilled Promise.

    ERIC Educational Resources Information Center

    Denton, David R.

    This report reviews the research on summer school and demonstrates that summer school makes a difference in students' lives if it is done right. A survey of more than 1,000 schools in the southern United States found that one-third of the responding schools did not offer summer school, many programs being the victims of budget cuts. Of those…

  12. Vertical structure of recent Arctic warming.

    PubMed

    Graversen, Rune G; Mauritsen, Thorsten; Tjernström, Michael; Källén, Erland; Svensson, Gunilla

    2008-01-01

    Near-surface warming in the Arctic has been almost twice as large as the global average over recent decades-a phenomenon that is known as the 'Arctic amplification'. The underlying causes of this temperature amplification remain uncertain. The reduction in snow and ice cover that has occurred over recent decades may have played a role. Climate model experiments indicate that when global temperature rises, Arctic snow and ice cover retreats, causing excessive polar warming. Reduction of the snow and ice cover causes albedo changes, and increased refreezing of sea ice during the cold season and decreases in sea-ice thickness both increase heat flux from the ocean to the atmosphere. Changes in oceanic and atmospheric circulation, as well as cloud cover, have also been proposed to cause Arctic temperature amplification. Here we examine the vertical structure of temperature change in the Arctic during the late twentieth century using reanalysis data. We find evidence for temperature amplification well above the surface. Snow and ice feedbacks cannot be the main cause of the warming aloft during the greater part of the year, because these feedbacks are expected to primarily affect temperatures in the lowermost part of the atmosphere, resulting in a pattern of warming that we only observe in spring. A significant proportion of the observed temperature amplification must therefore be explained by mechanisms that induce warming above the lowermost part of the atmosphere. We regress the Arctic temperature field on the atmospheric energy transport into the Arctic and find that, in the summer half-year, a significant proportion of the vertical structure of warming can be explained by changes in this variable. We conclude that changes in atmospheric heat transport may be an important cause of the recent Arctic temperature amplification. PMID:18172495

  13. Hydromania: Summer Science Camp Curriculum.

    SciTech Connect

    Moura, Joan

    1995-07-01

    In 1992, Bonneville Power Administration (BPA) and the US Department of Energy (DOE) began a collaborative pilot project with the Portland Parks and Recreation Community Schools Program and others to provide summer science camps to children in Grades 4--6. Camps run two weeks in duration between late June and mid-August. Sessions are five days per week, from 9 a.m. to 3 p.m. In addition to hands-on science and math curriculum, at least three field trips are incorporated into the educational learning experience. The purpose of the BPA/DOE summer camps is to make available opportunities for fun, motivating experiences in science to students who otherwise would have difficulty accessing them. This includes inner city, minority, rural and low income students. Public law 101-510, which Congress passed in 1990, authorizes DOE facilities to establish collaborative inner-city and rural partnership programs in science and math. A primary goal of the BPA summer hands on science camps is to bring affordable science camp experiences to students where they live. It uses everyday materials to engage students` minds and to give them a sense that they have succeeded through a fun hands-on learning environment.

  14. Summer Harvest in Saratov, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Russia's Saratov Oblast (province) is located in the southeastern portion of the East-European plain, in the Lower Volga River Valley. Southern Russia produces roughly 40 percent of the country's total agricultural output, and Saratov Oblast is the largest producer of grain in the Volga region. Vegetation changes in the province's agricultural lands between spring and summer are apparent in these images acquired on May 31 and July 18, 2002 (upper and lower image panels, respectively) by the Multi-angle Imaging SpectroRadiometer (MISR).

    The left-hand panels are natural color views acquired by MISR's vertical-viewing (nadir) camera. Less vegetation and more earth tones (indicative of bare soils) are apparent in the summer image (lower left). Farmers in the region utilize staggered sowing to help stabilize yields, and a number of different stages of crop maturity can be observed. The main crop is spring wheat, cultivated under non-irrigated conditions. A short growing season and relatively low and variable rainfall are the major limitations to production. Saratov city is apparent as the light gray pixels on the left (west) bank of the Volga River. Riparian vegetation along the Volga exhibits dark green hues, with some new growth appearing in summer.

    The right-hand panels are multi-angle composites created with red band data from MISR's 60-degree backward, nadir and 60-degree forward-viewing cameras displayed as red, green and blue respectively. In these images, color variations serve as a proxy for changes in angular reflectance, and the spring and summer views were processed identically to preserve relative variations in brightness between the two dates. Urban areas and vegetation along the Volga banks look similar in the two seasonal multi-angle composites. The agricultural areas, on the other hand, look strikingly different. This can be attributed to differences in brightness and texture between bare soil and vegetated land. The chestnut-colored soils in

  15. Your Best Summer Ever

    ERIC Educational Resources Information Center

    Cleaver, Samantha

    2012-01-01

    "It must be nice to have summers off." Only other teachers know just how short summer is, with much of August devoted to planning for the new school year. This article offers 17 fresh ideas for exploring, making money, and preparing for next year. Plus, a reading list that hits all the marks!

  16. Book Your Summer Vacation

    ERIC Educational Resources Information Center

    Texley, Juliana

    2012-01-01

    Summer's the time for teachers to travel, not only physically from the confines of the classroom to exotic places, but vicariously, through the magic of books. Summer adventures help teachers expand their experience and enrich their store of context so that they can offer their students more when school resumes in the fall. That's why each year…

  17. School Construction Summer Slam

    ERIC Educational Resources Information Center

    Jensen, Richard F.

    2012-01-01

    Every school has a list of renovations, upgrades and repairs that need attention, but many are too distracting and disruptive to carry out during the school year. Often, the best time to address these nagging construction projects is during the summer when students are on break and the campus is quieter. Although these "summer slammers" often are…

  18. Special Summer Section.

    ERIC Educational Resources Information Center

    G/C/T, 1981

    1981-01-01

    The section on summer programs for the gifted includes a directory of 62 programs and eight brief articles on independent learning; Project IDEA, a psychomotor program; miscellaneous offerings; The College Academy, Framingham College, MA; The College for Kids Project, IL; environmental education; an animal behavior course; and a summer academy.…

  19. Celebrate Summer with Reading

    ERIC Educational Resources Information Center

    Texley, Juliana

    2007-01-01

    School is out and the summer is full of both official and unofficial holidays that prompt us to enjoy science and the profession of sharing it. As in past years, the reviewers and editors of "NSTA Recommends"--ready and willing to share their enthusiasm for reading with you--have been gathering suggestions for the summer. So along with your beach…

  20. Under Summer Skies

    ERIC Educational Resources Information Center

    Texley, Juliana

    2009-01-01

    There's no better way to celebrate 2009, the International Year of Astronomy, than by curling up with a good book under summer skies. To every civilization, in every age, the skies inspired imagination and scientific inquiry. There's no better place to start your summer reading than under their influence. Here are a few selections identified by…

  1. What controls early or late onset of tropical North Atlantic hurricane season?

    NASA Astrophysics Data System (ADS)

    Zuo, Heng; Li, Tim; Liu, Jia; Peng, Melinda

    2016-06-01

    The occurrence of first hurricane in early summer signifies the onset of an active Atlantic hurricane season. The interannual variation of this hurricane onset date is examined for the period 1979-2013. It is found that the onset date has a marked interannual variation. The standard deviation of the interannual variation of the onset day is 17.5 days, with the climatological mean onset happening on July 23. A diagnosis of tropical cyclone (TC) genesis potential index (GPI) indicates that the major difference between an early and a late onset group lies in the maximum potential intensity (MPI). A further diagnosis of the MPI shows that it is primarily controlled by the local SST anomaly (SSTA). Besides the SSTA, vertical shear and mid-tropospheric relative humidity anomalies also contribute significantly to the GPI difference between the early and late onset groups. It is found that the anomalous warm (cold) SST over the tropical Atlantic, while uncorrelated with the Niño3 index, persists from the preceding winter to concurrent summer in the early (late) onset group. The net surface heat flux anomaly always tends to damp the SSTA, which suggests that ocean dynamics may play a role in maintaining the SSTA in the tropical Atlantic. The SSTA pattern with a maximum center in northeastern tropical Atlantic appears responsible for generating the observed wind and moisture anomalies over the main TC development region. A further study is needed to understand the initiation mechanism of the SSTA in the Atlantic.

  2. Late paternities.

    PubMed

    Cohen, Jean

    2007-06-01

    Late paternities are frequent. Very often these couples ask for medically assisted procreation. In general, it is considered that the couple should not be treated differently from the couple where the father is younger. Recent studies show a certain number of specific risks linked to the late paternities. Doctors and society do not act in the same way towards men and women: a 'sensible age' for women to no longer attempt pregnancy has been set in many countries at 42 years of age, whereas men aged 80 can benefit from IVF attempts and be reimbursed by the state or insurance companies. This is an obvious inequity. PMID:17579995

  3. Vertical migration and nighttime distribution of adult bloaters in Lake Michigan

    USGS Publications Warehouse

    TeWinkel, Leslie M.; Fleischer, Guy W.

    1999-01-01

    The vertical migration and nighttime vertical distribution of adult bloaters Coregonus hoyi were investigated during late summer in Lake Michigan using acoustics simultaneously with either midwater or bottom trawling. Bloaters remained on or near bottom during the day. At night, bloaters were distributed throughout 30-65 m of water, depending on bottom depth. Shallowest depths of migration were not related to water temperature or incident light. Maximum distances of migration increased with increasing bottom depth. Nighttime midwater densities ranged from 0.00 to 6.61 fish/1,000 mA? and decreased with increasing bottom depth. Comparisons of length distributions showed that migrating and nonmigrating bloaters did not differ in size. However, at most sites, daytime bottom catches collected a greater proportion of larger individuals compared with nighttime midwater or bottom catches. Mean target strengths by 5-m strata indicated that migrating bloaters did not stratify by size in the water column at night. Overall, patterns in frequency of empty stomachs and mean digestive state of prey indicated that a portion of the bloater population fed in the water column at night. Bloater diet composition indicated both midwater feeding and bottom feeding. In sum, although a portion of the bloater population fed in the water column at night, bloaters were not limited to feeding at this time. This research confirmed that bloaters are opportunistic feeders and did not fully support the previously proposed hypothesis that bloater vertical migration is driven by the vertically migrating macroinvertebrate the opossom shrimp Mysis relicta.

  4. Dynamics of summer tropopause folds over the eastern Mediterranean and the Middle East.

    NASA Astrophysics Data System (ADS)

    Tyrlis, Evangelos; Sprenger, Michael; Wernli, Heini; Lelieveld, Jos

    2013-04-01

    Tropopause folds are atmospheric structures occurring in the subtropical and extratropical regions, while deep folds are a special category of tropopause folds, identified predominantly in the extratropics with their dynamics closely linked to those of midlatitude baroclinic waves. In the zonal mean, a distinct seasonal cycle is recognized featuring a summer minimum, especially for deep midlatitude folds, due to the weaker summer midlatitude baroclinicity. However, the investigation of the seasonal cycle of the vertical distribution of potential vorticity (PV) confirmed the findings of an earlier 1-year global climatolology that reported abundant summer folds over a sector ranging from the eastern Mediterranean to Afghanistan. This region lies at the western and northern flanks of the upper level South Asian Monsoon anticyclone. From late spring, it is gradually brought under the influence of the zonally asymmetric background state induced by the monsoon, which features an elevated tropopause and depression of isentropic surfaces. As areas of sharply sloping isentropes develop over the eastern Mediterranean and Iran-Afghanistan, which are exposed to the midlatitude westerlies, subsidence and tropopause fold formation are favored. The present study aims at the further quantification of the above initial findings through the compilation of a comprehensive climatology of folds over the eastern Mediterranean and the Middle East. The methodology is based on an algorithm that detects folds as areas featuring multiple crossings of the dynamical tropopause. The analysis is based on the ERA-Interim data interpolated on a 1x1 regular grid, spanning the period 1979-2012. The methodology allows the identification of geometrical features of tropopause folds and their classification into deep and shallow structures. This allows us the understanding of the distinct dynamical links with the monsoon on intra-seasonal timescales and the investigation of the evolution and vertical

  5. Evolution of the Southern Hemisphere subpolar middle atmosphere during summer and autumn

    NASA Technical Reports Server (NTRS)

    Miles, T.; Grose, W. L.; Remsberg, E. E.; Lingenfelser, G.

    1994-01-01

    The evolution of zonal wind and zonal wavenumber one (wave 1) in the Southern Hemisphere subpolar middle atmosphere is described for the period December 1978 - May 1979 using temperature and ozone measurements from the Limb Infrared Monitor of the Stratosphere (LIMS) experiment. In late December maximum zonal easterlies of approx. -70 m/s are observed at 0.1 mb, 60 deg S. A zonal flow reversal occurs during late February and westerlies subsequently increase to 60-70 m/s in the upper stratosphere by April - May. LIMS zonal winds are compared with rocketsonde measurements and nadir sounder (derived) winds for summer and autumn. Although quantitative agreement is found at stratospheric levels, substantial discrepancies are evident in the mesosphere, most likely a reflection of sampling and resolution differences in the respective datasets. Stationary and traveling wave 1 temperature disturbances (amplitudes approx. 1 - 2 K at 60 deg S) are observed by LIMS during summer. The stationary wave is confined to the lower stratosphere near the level of zero zonal- mean wind flow, whereas the traveling wave is prominent in the middle stratosphere moves west at a rate similar to the zonal-mean wind, and exhibits a vertical - meridional structure similar to a P(sub 4)(sup 1) normal mode Rossby wave. A substantial intensification of wave 1 activity occurs during autumn (amplitudes approx. 5 - 10 K), which is found to be associated with an upward-directed Eliasse - Palm flux near the subpolar tropopause level. Evidence relating wave 1 activity in the lower - middle stratosphere to the occurrence of zonal ozone perturbations of 10% - 20% amplitude is presented for summer and autumn.

  6. IISME Summer Fellowship Program

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the summer of 1997, NASA-Ames scientists served as mentors to six teachers who worked as IISME (Industry Initiatives for Science and Math Education) Teacher Fellows over the summer. These six teachers were among 91 IISME Teacher Fellows working at various corporate, government agency, and university sites throughout the San Francisco Bay Area. These NASA-Ames fellowship positions are described in brief. One requirement of the IISME Summer Fellowship program is that teachers develop a personal Action Plan for classroom transfer. These Action Plans are published in abstract form in an annual catalog. I have also attached the abstracts of NASA-Ames teachers.

  7. Understanding the influence of predation on introduced fishes on juvenile salmonids in the Columbia River Basin: Closing some knowledge gaps. Late summer and fall diet and condition of smallmouth bass, walleye, and channel catfish in the middle Columbia River, USA. Interim Report of Research 2011.

    USGS Publications Warehouse

    Rose, Brien P.; Hansen, Gabriel S.; Weaver, Michele; Ayers, David; Van Dyke, Erick S.; Mesa, Matthew G.

    2012-01-01

    American shad Alosa sapidissima in the middle Columbia River (MCR)—a high energy food available in the summer and fall—may be contributing to the increased growth and enhanced condition of nonnative piscivores. To test this hypothesis we quantified the late summer and autumn diets of smallmouth bass Micropterus dolomieu, walleye Sander vitreus, and channel catfish Ictalurus punctatus in the three lowermost reservoirs on the Columbia River (Bonneville [BON], The Dalles [TDA], and John Day [JDA]). The diet of smallmouth bass (SMB) was fairly similar among reservoirs, with crustaceans (52–82%) and fish (13–38%) being the dominant prey groups by percent mass. Cottidae were usually the dominant fish prey in the diet of SMB at all areas and the contribution of juvenile shad ranged from 0–8.2%. Fish (mostly Cyprinidae and Cottidae) were always the dominant prey item for walleye (WAL) at all areas and at all times, ranging from 70–100% of their diet by mass. Juvenile American shad composed from 10–27% (by mass) of the diet of walleye, depending on area and month. For channel catfish (CHC), the most common prey items consumed were crustaceans (20%–80% by mass) and unidentified items (30%–80%). Fish represented a relatively small component (< 4%) of their diet. We also evaluated the condition of SMB and WAL by determining relative weights (Wr) and hepatosomatic indices (HSI). Mean Wr for SMB greater than 300 mm ranged from 0.89 to 0.94 depending on area and month and showed a significant increase from August to September for fish in BON only. Overall, mean Wr of WAL was similar at all areas, ranging from 0.89–0.91, and increased significantly from September to mid-October and November for fish in TDA only. Overall, mean HSI of SMB ranged from 1.18 to 1.48, did not differ between fish in different reservoirs, and increased significantly from September to mid-October and November for fish from the lower JDA only. Mean HSI of WAL was significantly higher in

  8. Northeast China summer temperature and North Atlantic SST

    NASA Astrophysics Data System (ADS)

    Wu, Renguang; Yang, Song; Liu, Shi; Sun, Li; Lian, Yi; Gao, Zongting

    2011-08-01

    A previous study revealed a close relationship between interannual variations of northeast China (NEC) summer temperature and a tripole sea surface temperature (SST) anomaly pattern in the North Atlantic in preceding spring. The present study investigates the change in the above relationship and the plausible causes for the change. A tripole SST index is defined with its positive value corresponding to positive SST anomalies in the tropics and midlatitudes and negative SST anomalies in the subtropics. The tripole SST anomaly pattern has a weak correlation with NEC summer temperature during the 1950s through the mid-1970s, in sharp contrast to the 1980s and 1990s. This change is related to the difference in the persistence of the tripole SST pattern. Before the late 1970s, the tripole SST pattern weakened from spring to summer, and thus, the spring North Atlantic tripole SST pattern had a weak connection with NEC summer temperature. On the contrary, after the late 1970s, the tripole SST pattern displayed a tendency of persistence from spring to summer, contributing to circulation changes that affected NEC summer temperature. There are two factors for the persistence of the tripole SST pattern from spring to summer. One is the North Atlantic air-sea interaction, and the other is the persistence of SST anomalies in the eastern equatorial Pacific during the decay of El Niño-Southern Oscillation (ENSO). It is shown that the North Atlantic SST anomalies can have an impact on NEC summer temperature independent of ENSO.

  9. Chemical Physics Summer School

    SciTech Connect

    2002-06-28

    The Gordon Research Conference (GRC) on Chemical Physics Summer School was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  10. A Summer Camp Assessment.

    ERIC Educational Resources Information Center

    Pratte, Janice L.; DiNardi, Salvatore R.

    1979-01-01

    Reported are the results of a project assessing the impact of a revised Massachusetts sanitary code on 500 summer camps for children. The study compared camp compliances with the proposed regulations to the level of compliance with existing regulations. (BT)

  11. Summer Water Safety Guide

    MedlinePlus

    ... this flyer at your pool, community center and beach bulletin boards. • Visit RedCross. org for more swimming ... GREAT SUMMER SAVINGS AT RED CROSS STORE! VINTAGE BEACH TOWEL ALL RED CROSS GEAR USE DISCOUNT CODE: ...

  12. Summer Success Story.

    ERIC Educational Resources Information Center

    Matika, Francis W.

    1994-01-01

    Pennsylvania's Beaver Valley Intermediate Unit built a collaborative 2-week summer academy, opening it to students in the other 14 school districts in the county. Cooperation among all the districts provided students opportunities for expanded learning experiences. (MLF)

  13. Effect of sea-ice melt on inherent optical properties and vertical distribution of solar radiant heating in Arctic surface waters

    NASA Astrophysics Data System (ADS)

    Granskog, Mats A.; Pavlov, Alexey K.; Sagan, Sławomir; Kowalczuk, Piotr; Raczkowska, Anna; Stedmon, Colin A.

    2015-10-01

    The inherent optical properties (IOPs) of Polar Waters (PW) exiting the Arctic Ocean in the East Greenland Current (EGC) and of the inflowing Atlantic waters (AW) in the West Spitsbergen Current (WSC) were studied in late summer when surface freshening due to sea-ice melt was widespread. The absorption and attenuation coefficients in PW were significantly higher than previous observations from the western Arctic. High concentrations of colored dissolved organic matter (CDOM) resulted in 50-60% more heat deposition in the upper meters relative to clearest natural waters. This demonstrates the influence of terrigenous organic material inputs on the optical properties of waters in the Eurasian basin. Sea-ice melt in CDOM-rich PW decreased CDOM absorption, but an increase in scattering nearly compensated for lower absorption, and total attenuation was nearly identical in the sea-ice meltwater layer. This suggests a source of scattering material associated with sea-ice melt, relative to the PW. In the AW, melting sea-ice forms a stratified surface layer with lower absorption and attenuation, than well-mixed AW waters in late summer. It is likely that phytoplankton in the surface layer influenced by sea-ice melt are nutrient limited. The presence of a more transparent surface layer changes the vertical radiant heat absorption profile to greater depths in late summer both in EGC and WSC waters, shifting accumulation of solar heat to greater depths and thus this heat is not directly available for ice melt during periods of stratification.

  14. Modeling the Frozen-In Anticyclone in the 2005 Arctic Summer Stratosphere

    NASA Technical Reports Server (NTRS)

    Allen, D. R.; Douglass, A. R.; Manney, G. L.; Strahan, S. E.; Krosschell, J. C.; Trueblood, J.

    2010-01-01

    Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N2O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from approximately 580 to 1100 K (approximately 25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N2O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the VanLeer Icosahedral Triangular Advection isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at approximately 70-90 deg N, marked with elevated N2O. GMI, Replay, and VITA all reliably simulted the spin-up of the FrIAC, although the GMI and Replay peak N2O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7th and 14th of April. The VITA and Replay simulations transported the N2O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical hear during the anticyclonic phase, and it thereby protected the embedded N20 anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N2O anomaly exposed to

  15. The Forest, Part 4: Late Summer and Fall

    ERIC Educational Resources Information Center

    Johnson, Elfriede Nemetz

    1973-01-01

    Briefly describes the ecology of a deciduous forest, and suggests activities for observing and appreciating the changes that occur during the Fall. Simple experiments relating to mosses and lichens are outlined. (JR)

  16. Outside the paradigm: satellite discoveries of large summer chlorophyll blooms

    NASA Astrophysics Data System (ADS)

    Wilson, C.

    2010-12-01

    It is becoming increasingly rare to discover a new natural phenomenon on our planet that we don’t understand. Such a discovery has been made from satellite data showing the consistence occurrence of summer chlorophyll blooms in both the eastern region of the North Pacific Subtropical Gyre and in the southern Indian Ocean off of Madagascar. In the open ocean, outside of upwelling regions, phytoplankton blooms generally occur in the springtime, when sufficient light because available to utilize nutrients brought into the mixed-layer by winter mixing. Neither the NE Pacific blooms nor the blooms off of Madagascar fit this paradigm. The North Pacific blooms appear as ocean oases in the middle of the oligotrophic gyre, without an obvious source of nutrients to sustain the elevated chlorophyll. These blooms have a consistent seasonality, developing in the late summer, July-Sept, and lasting anywhere between 6 weeks to 5 months. Although they do not appear every year, they have been observed in 12 of 18 years of satellite ocean color data. These features are quite extensive, spanning hundreds of kms; the largest observed bloom, in 1997, matched the size of California (>400,000 km2). The blooms also have a consistent location, developing northeast of Hawaii, in the region bounded by 27-33°N and 135-155°W. Based on available in-situ data from the region it has been proposed that nitrogen fixation and the vertical migration of Rhizosolenia diatom mats below the nutricline as two possible mechanisms supplying nutrients (nitrogen) to these blooms. However, it remains unknown what physical conditions cause the blooms to develop in this one very specific spot of the N. Pacific. Satellite ocean color data has also led to the discovery of large chlorophyll blooms that develop east of Madagascar in Feb-Apr (austral summer). These blooms originate at the southern tip of Madagascar and extend eastward to 70°E, covering a distance of ~2500 km. In the SeaWiFS era (1997-present

  17. Two distinct mechanisms on East Asian surface temperature variability during summer

    NASA Astrophysics Data System (ADS)

    Yeh, Sang-Wook; Won, Yujin; Yeo, Sae-Rim; Yim, Bo Young

    2016-04-01

    The surface air temperature (SAT) in East Asia was examined in order to find global scale versus local scale factors that affected its variability during the summer (June-July-August). It was found that there exist a distinguished sub-seasonal variation, showing remarkable differences in its variability between early summer (June) and late summer (July and August). In particular, we pay attention to the variability of Korean SAT. This study revealed that Korean SAT during early and late summer is affected by different principal modes of SAT over East Asia domain. In particular, there was a significant warming trend in the Korean SAT during early summer, which was primarily influenced by a global warming trend that manifested in East Asia. Meanwhile, there exists the local scale variability of the Korean SAT, which is independent from the global warming signal. During late summer, on the other hand, the SAT variability in Korea was not significantly influenced by a warming trend, although the warming signal still accounts for majority of the SAT variance over East Asia. Instead, Korean SAT during late summer appears to be closely related to the atmospheric variability originated from the western tropical sea surface temperature (SST) forcing. These results implied that the East Asian SAT variability during early and late summer has different sources.

  18. STRAPOLETE : Studying summer polar stratosphere

    NASA Astrophysics Data System (ADS)

    Payan, Sebastien

    2010-05-01

    The polar stratosphere in the summertime remains largely unexplored. Dynamical conditions are characterized by large scale transport and mixing between air masses of higher and lower latitude origins. Understanding these exchanges is crucial since they have a large impact on the distribution of trace gases and aerosols at polar latitudes, and thus on the stratospheric ozone budget. Ozone change affects the radiative balance, the coupling between troposphere and stratosphere, and therefore the climate. In the framework of the International Polar Year, the STRAPOLETE project starts on January 2009. It is associated with a successful balloon borne campaign which took place close to Kiruna (Sweeden) from 2 August 2009 to 12 September 2009 with eight balloon flights. During this campaign the main characteristics of the summertime arctic stratosphere have been captured. The data set obtained using UV-visible and infrared instruments, remote and in situ sensing embarked spectrometers provided detailed information on vertical distributions of more than fifteen chemical tracers and reactive species from the upper troposphere to the middle stratosphere. A number of in situ optical aerosol counters, a UV-visible remote spectrometer for the aerosol extinction and a photopolarimeter provided information on the nature and size distribution of the stratospheric aerosols. These balloon measurements with high precision and high vertical resolution are relevant to qualify the dynamical processes occurring in this region during summertime, the aerosols variability, the bromine abundance and establish a reference state of the polar summer stratosphere. The data set is completed by satellite data offering large spatial coverage of the region of interest. Data analysis is made using relevant dynamical (trajectory calculations, contour advection model) and chemistry-transport models (CTM) to highlight major mechanisms that control the distribution of tracers, aerosols and bromine. An

  19. EOS Microwave Limb Sounder Observations of 'Frozen-in' Anticyclonic Air in Arctic Summer

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Livesey, N. J.; Jimenez, C. J.; Pumphrey, H. C.; Santee, M. L.; MacKenzie, I. A.; Waters, J. W.

    2006-01-01

    A previously unreported phenomenon, a 'frozen-in' anticyclone (FrIAC) after the 2005 Arctic spring vortex breakup, was discovered in Earth Observing System (EOS) Microwave Limb Sounder (MLS) long-lived trace gas data. A tongue of low-latitude (high-N2O, low-H2O) air was drawn into high latitudes and confined in a tight anticyclone, then advected intact in the summer easterlies through late August. A similar feature in O3 disappeared by early April as a result of chemical processes. The FrIAC was initially advected upright at nearly the same speed at all levels from approx.660 to 1300 K (approx.25-45 km); increasing vertical wind shear after early June tilted the FrIAC and weakened it at higher levels. The associated feature in PV disappeared by early June; transport calculations fail to reproduce the remarkable persistence of the FrIAC, suggesting deficiencies in summer high-latitude winds. The historical PV record suggests that this phenomenon may have occurred several times before. The lack of a persistent signature in O3 or PV, along with its small size and rapid motion, make it unlikely that a FrIAC could have been reliably identified without hemispheric daily longlived trace gas profiles such as those from EOS MLS.

  20. My Summer Vacation

    ERIC Educational Resources Information Center

    Galus, Pamela

    2010-01-01

    In this article, a science teacher from the Midwest reflects on her summer vacation to the Gulf of Mexico. She felt that this vacation would help improve her teaching about the environmental problems in the gulf and elsewhere. After all, anyone can show photos of oil-laden birds and dead sea turtles and read news clips of a distant place, but to…

  1. Summer Reading Loss

    ERIC Educational Resources Information Center

    Mraz, Maryann; Rasinski, Timothy V.

    2007-01-01

    Summer reading loss is a documented reality for many students. It is often of greatest concern for those who are already at risk, who typically have limited access to reading materials at home and whose parents or caregivers may be reluctant or unsure of how to help. By raising parents' awareness of the importance of supporting their children's…

  2. Active Healthy Summer

    ERIC Educational Resources Information Center

    Elliott, Eloise

    2005-01-01

    Summer break is almost here for most elementary teachers and students. Warmer weather and additional free time to make choices create more opportunities to be physically active, whether home alone or out with friends and family. This article describes ways by which physical education specialists can encourage students' physical activity by…

  3. Use Your Summer Wisely

    ERIC Educational Resources Information Center

    Vick, Julie Miller; Furlong, Jennifer S.

    2007-01-01

    Academics welcome summer with a collective sigh of relief. Finally they can get to those tasks that are nearly impossible to accomplish during a busy academic year: working on that manuscript, completing the revisions on an article, learning the new laboratory technique from the colleague across the hall. However, those going on the job market in…

  4. Books for Summer Reading.

    ERIC Educational Resources Information Center

    [Editors

    2001-01-01

    Teachers and education professors suggest various nonfiction and fiction books for summer reading enjoyment, from Robert Putnam's "Bowling Alone," C.A. Bowers's "Let Them Eat Data," and Larry McMurtry's "Roads: Driving America's Great Highways" to Kent Hauf's "Plainsong, J.M. Coetzee's "Disgrace," and Michael Cunningham's "The Hours." (MLH)

  5. Best New Summer Books

    ERIC Educational Resources Information Center

    Trierweiler, Hannah; Cleaver, Samantha

    2007-01-01

    When a colleague and friend gives you a new kids' book and says, "You have to read this," you pay attention. That's why the author asked a team of top teachers and librarians to share new favorites for summer. Here are their picks for every reader, each bearing a teachers' stamp of approval.

  6. Waunakee's Summer Science Program.

    ERIC Educational Resources Information Center

    O'Neil, J. Peter

    1981-01-01

    Describes Waunakee Community School's six-week Summer Science Program for students entering the seventh grade. Students are selected for this science enrichment program on the basis of interest, ability, and maturity. Program content includes wetlands, forests, prairies, and animals, concluding with a camping trip. (DS)

  7. Help for the Summer

    ERIC Educational Resources Information Center

    Greifner, Laura

    2006-01-01

    Throngs of people cover the concrete walkways of Dorney Park, an amusement park about an hour north of Philadelphia. Employees under the age of 18 make up about 40 percent of the park's summer workforce, and, park officials say, are even more crucial to its operations later in the season, when college-student employees go back to school and…

  8. Books for Summer Reading.

    ERIC Educational Resources Information Center

    Phi Delta Kappan, 1996

    1996-01-01

    Suggests several novels for educators' summer reading enjoyment, including classics by Robert Pirsig, Robertson Davies, John Steinbeck, Albert Camus, and Charles Dickens. Educators might also read Alex Kotlowitz's "There Are No Children Here" (Doubleday, 1991) and Sharon Quint's "Schooling Homeless Children" (Teachers College Press, 1994) to gain…

  9. Summer Fish Camp.

    ERIC Educational Resources Information Center

    Remick, Dennis; Pulu, Tupou L.

    The booklet presents a description and illustrates, with photographs, the Eskimo lifestyle and the kinds of activities that occur at a summer fish camp on the Yukon River. Eleven suggested activities are listed for the teacher to present when using the booklet. Activities include studying the map of Alaska; tracing the life cycle of the fish;…

  10. Books for Summer Reading.

    ERIC Educational Resources Information Center

    Phi Delta Kappan, 1993

    1993-01-01

    Recommends fine fiction for summer reading, including Nadine Gordimer's "My Son's Story" (1991), Lillian Smith's "Strange Fruit" (1944), Josephine Hart's "Damage" (1991), Jane Smiley's "A Thousand Acres" (1991), and George Eliot's "Middlemarch" (1874). Nonfiction suggestions include Harlan Lane's "Mask of Benevolence" (1992), Diane Ackerman's "A…

  11. Summer Study Abroad.

    ERIC Educational Resources Information Center

    Cohen, Gail A., Ed.

    This catalog describes summer study abroad programs around the world for students of college age and up. The included information was obtained from surveys conducted by the Institute of International Education in September 1978. The catalog contains programs of interest to the pre-college student who wants to improve his language skills before…

  12. A Flying Summer Camp

    ERIC Educational Resources Information Center

    Mercurio, Frank X.

    1975-01-01

    Describes a five-day summer camp which provided 12 children, ages 9-14, with a complete flying experience. The training consisted of ground school and one hour actual flying time, including the basics of aircraft control and a flight prepared and executed by the students. (MLH)

  13. Summer Roof Maintenance.

    ERIC Educational Resources Information Center

    Liscum, Curtis L.

    1999-01-01

    Presents the items to review in roofing maintenance to prepare for the impact of summer, including checking drainage, roof-field surface and membrane, flashings, sheet metal, and rooftop equipment, such as skylights and penthouses. A list of roofing facts facility managers should know are highlighted. (GR)

  14. Summer Reading That Inspires

    ERIC Educational Resources Information Center

    Texley, Juliana

    2012-01-01

    Why did you decide on science as a career? For many, it was the inspiration of a mentor or model--an explorer who could communicate excitement and a sense of adventure to others. During the school year, teachers take on that role of motivator for students. But as they recharge over summer break, it is great to treat themselves again to the stories…

  15. Superheroes and Summer Reading.

    ERIC Educational Resources Information Center

    Meyer, Ron; Buckner, Joyce

    1980-01-01

    To combat summer learning loss among remedial readers, teachers and consultants in the Omaha, Nebraska, Title I program designed a series of comic-book reading units and mailed them to students' homes. Parents were pleased with the project and it appeared that less reading skill had been lost by September. (SJL)

  16. International Summer Programs.

    ERIC Educational Resources Information Center

    Cox, June

    1979-01-01

    The article describes five summer programs for gifted and talented students offered internationally. The programs outlined are workshops in the publication arts, a study of humanistic development; computer science, writing, and photography workshops; a language study; a historical/social study of English history; and a workshop on photography,…

  17. Summer Youth Report, 1999.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Economic Security, St. Paul.

    This document presents 1999 outcome information for Minnesota's Summer Youth Employment and Training Programs (SYETPs). The document begins with a summary of statewide outcome information for the SYETPs, which served a total of 4,644 youths under Job Training Partnership Act Title IIB and 2,993 youths through the Minnesota Youth Program at an…

  18. Summer Programs, 1976.

    ERIC Educational Resources Information Center

    Rudolph, Thomas

    This document examines the 1976 High School Summer Programs and one evening program of the Atlanta Public Schools. This evaluation reports on the following variables: (1) school and faculty selection, (2) teacher certification, (3) enrollment and attendance, (4) pass-fail ratio of students, (5) cost data, and (6) questionnaire data from…

  19. Summer Youth Forestry Institute

    ERIC Educational Resources Information Center

    Roesch, Gabrielle E.; Neuffer, Tamara; Zobrist, Kevin

    2013-01-01

    The Summer Youth Forestry Institute (SYFI) was developed to inspire youth through experiential learning opportunities and early work experience in the field of natural resources. Declining enrollments in forestry and other natural resource careers has made it necessary to actively engage youth and provide them with exposure to careers in these…

  20. Martian north pole summer temperatures - Dirty water ice

    NASA Technical Reports Server (NTRS)

    Kieffer, H. H.; Martin, T. Z.; Chase, S. C., Jr.; Miner, E. D.; Palluconi, F. D.

    1976-01-01

    Broadband thermal and reflectance observations of the Martian north polar region in late summer yield temperatures for the residual polar cap near 205 K with albedos near 43 percent. The residual cap and several outlying smaller deposits are water ice with included dirt; there is no evidence for any permanent carbon dioxide polar cap.

  1. Manufacturing Dissent: Labor Revitalization, Union Summer and Student Protest

    ERIC Educational Resources Information Center

    Van Dyke, Nella; Dixon, Marc; Carlon, Helen

    2007-01-01

    During the late 1990s, college students across the United States mobilized around labor issues. Our research explores whether this explosion of student protest activity was generated, in part, by concerted efforts of the AFL-CIO through its Union Summer college student internship program. A statistical analysis of factors influencing the location…

  2. Summer Reading Summer Not: How Project READS Can Advance Equity

    ERIC Educational Resources Information Center

    Kim, James S.

    2010-01-01

    This paper has three goals. First, it describes the broader research on summer reading loss. Second, it discusses how research and development efforts informed the key components of Project READS (Reading Enhances Achievement During Summer), a scaffolded voluntary summer reading intervention for children in grades 3 to 5. The second part of the…

  3. Making Summer Count: How Summer Programs Can Boost Children's Learning

    ERIC Educational Resources Information Center

    McCombs, Jennifer Sloan; Augustine, Catherine; Schwartz, Heather; Bodilly, Susan; McInnis, Brian; Lichter, Dahlia; Cross, Amanda Brown

    2012-01-01

    During summer vacation, many students lose knowledge and skills. By the end of summer, students perform, on average, one month behind where they left off in the spring. Participation in summer learning programs should mitigate learning loss and could even produce achievement gains. Indeed, educators and policymakers increasingly promote summer…

  4. A numerical model simulation of a summer reversal of the Beaufort Gyre

    NASA Astrophysics Data System (ADS)

    Preller, Ruth H.; Posey, Pamela G.

    1989-01-01

    Ice drift derived from the Polar Ice Prediction System (PIPS) is used to study the sea ice circulation of the Beaufort and Chukchi seas in the late summer. Model simulations for the years 1983, 1986 and 1987 show that the anticyclonic Beaufort Gyre reverses to cyclonic circulation in the late summer. This result is due to a change in the mean atmospheric surface pressure. Drifting buoys from 1983 confirm this reversal of the Beaufort Gyre.

  5. Summer 2014 Pathways Report

    NASA Technical Reports Server (NTRS)

    Hand, Zachary

    2014-01-01

    Over the summer I had the exciting opportunity to work for NASA at the Kennedy Space Center as a Mission Assurance Engineering intern. When I was offered a position in mission assurance for the Safety and Mission Assurance directorate's Launch Services Division, I didn't really know what I would be doing, but I knew it would be an excellent opportunity to learn and grow professionally. In this report I will provide some background information on the Launch Services Division, as well as detail my duties and accomplishments during my time as an intern. Additionally, I will relate the significance of my work experience to my current academic work and future career goals. This report contains background information on Mission Assurance Engineering, a description of my duties and accomplishments over the summer of 2014, and relates the significance of my work experience to my school work and future career goals. It is a required document for the Pathways program.

  6. The Summer School Alpbach

    NASA Astrophysics Data System (ADS)

    Gitsch, Michaela; Manoharan, Periasamy K.

    2015-02-01

    Sixty young, highly qualified European science and engineering students converge annually for stimulating 10 days of work in the Austrian Alps. Four teams are formed, each of which designs a space mission, which are then judged by a jury of experts. Students learn how to approach the design of a satellite mission and explore new and startling ideas supported by experts. The Summer School Alpbach enjoys more than 30 years of tradition in providing in-depth teaching on different topics of space science and space technology, featuring lectures and concentrated working sessions on mission studies in self-organised working groups. The Summer School is organised by the Austrian Research Promotion Agency (FFG) and co-sponsored by the European Space Agency (ESA), the International Space Science Institute (ISSI), and the national space authorities of its member and cooperating states.

  7. Start a Summer Arts Program.

    ERIC Educational Resources Information Center

    Pedersen, Kirie

    1984-01-01

    Tips on organizing a creative teaching experience for summer vacation time are offered. Program organization, student selection, course content, publicity, and funding are aspects to be considered when planning a summer arts program. (DF)

  8. Goddard Summer Interns: Alejandro Arambula

    NASA Video Gallery

    Alejandro Arambula is an aerospace engineering student at M.I.T. and a 2011 summer intern in Goddard's Propulsion Lab. This summer he is working with his mentor Khary Parker in building a test asse...

  9. Dissociated Vertical Deviation

    MedlinePlus

    ... Eye Terms Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Dissociated Vertical Deviation En Español Read in Chinese What is Dissociated Vertical Deviation (DVD)? DVD is ...

  10. 75 FR 2820 - Fisheries of the Northeastern United States; Summer Flounder Fishery; Quota Transfer

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... (58 FR 65936), provided a mechanism for summer flounder quota to be transferred from one state to... necessitate a state quota transfer (70 FR 53969). This rule specified that such late- season quota transfers... United States; Summer Flounder Fishery; Quota Transfer AGENCY: National Marine Fisheries Service...

  11. Arctic Summer Ice Processes

    NASA Technical Reports Server (NTRS)

    Holt, Benjamin

    1999-01-01

    The primary objective of this study is to estimate the flux of heat and freshwater resulting from sea ice melt in the polar seas. The approach taken is to examine the decay of sea ice in the summer months primarily through the use of spaceborne Synthetic Aperture Radar (SAR) imagery. The improved understanding of the dynamics of the melt process can be usefully combined with ice thermodynamic and upper ocean models to form more complete models of ice melt. Models indicate that more heat is absorbed in the upper ocean when the ice cover is composed of smaller rather than larger floes and when there is more open water. Over the course of the summer, floes disintegrate by physical forcing and heating, melting into smaller and smaller sizes. By measuring the change in distribution of floes together with open water over a summer period, we can make estimates of the amount of heating by region and time. In a climatic sense, these studies are intended to improve the understanding of the Arctic heat budget which can then be eventually incorporated into improved global climate models. This work has two focus areas. The first is examining the detailed effect of storms on floe size and open water. A strong Arctic low pressure storm has been shown to loosen up the pack ice, increase the open water concentration well into the pack ice, and change the distribution of floes toward fewer and smaller floes. This suggests episodic melting and the increased importance of horizontal (lateral) melt during storms. The second focus area is related to an extensive ship-based experiment that recently took place in the Arctic called Surface Heat Budget of the Arctic (SHEBA). An icebreaker was placed purposely into the older pack ice north of Alaska in September 1997. The ship served as the base for experimenters who deployed extensive instrumentation to measure the atmosphere, ocean, and ice during a one-year period. My experiment will be to derive similar measurements (floe size, open

  12. Summer Learning: Accelerating Student Success

    ERIC Educational Resources Information Center

    Pitcock, Sarah; Seidel, Bob

    2015-01-01

    As numerous studies from 1906 on have confirmed, children lose ground in learning if they lack opportunities for building skills over the summer. Nonetheless, summer learning loss comes up but rarely in the national discussion of education reform. By the end of summer, students perform on average one month behind where they left off in the spring.…

  13. Summer Migrant Education Administrative Manual.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh.

    This manual helps local education agencies (LEAs) create and develop summer school programs for children of migrant workers in North Carolina. It includes models for summer programs in music, art, vocational education, reading, language arts and math. The manual includes sections on financing, planning, student transportation, summer lunch…

  14. Vertical Map Storage.

    ERIC Educational Resources Information Center

    Perry, Joanne M.

    1982-01-01

    Discusses the superiority of vertical filing of maps in compressor-style vertical units over horizontal filing in drawers, emphasizing such factors as physical protection of the collection, ease of filing and retrieval, and efficient use of space. Disadvantages of vertical filing are also reviewed. (Author/JL)

  15. Vertical bounce of two vertically aligned balls

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2007-11-01

    When a tennis ball rests on top of a basketball and both drop to the floor together, the tennis ball is projected vertically at high speed. A mass-spring model of the impact, as well as air track data, suggest that the tennis ball should be projected at relatively low speed. Measurements of the forces on each ball and the bounce of vertically aligned superballs are used to resolve the discrepancy.

  16. Vertical cable surveys deliver additional seismic data

    SciTech Connect

    1995-12-01

    Texaco and a Norwegian seismic firm have patented a new system for deploying hydrophones on vertical cables for offshore surveys. The system was used in Texaco North Sea UK Ltd.`s Strathspey field during the summer. The new technique was introduced in the article, ``Peaceful use for war technology,`` published in Texaco UK`s Agenda monthly news magazine, October 1995. That article is summarized here. Using technology developed by the US Navy for antisubmarine warfare, the vertical-cable survey relies on hydrophones attached at regular intervals vertically along cables secured to the ocean floor and held taut by a buoy. The shooting vessel fires the airguns in a pattern over a large area on the surface, over and around the cables. The cables are then moved to a new location and the process is repeated, up to six times in the Strathspey application described here.

  17. Improvement of vertical profiles of raindrop size distribution from micro rain radar using 2D video disdrometer measurements

    NASA Astrophysics Data System (ADS)

    Adirosi, E.; Baldini, L.; Roberto, N.; Gatlin, P.; Tokay, A.

    2016-03-01

    A measurement scheme aimed at investigating precipitation properties based on collocated disdrometer and profiling instruments is used in many experimental campaigns. Raindrop size distribution (RSD) estimated by disdrometer is referred to the ground level; the collocated profiling instrument is supposed to provide complementary estimation at different heights of the precipitation column above the instruments. As part of the Special Observation Period 1 of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, conducted between 5 September and 6 November 2012, a K-band vertically pointing micro rain radar (MRR) and a 2D video disdrometer (2DVD) were installed close to each other at a site in the historic center of Rome (Italy). The raindrop size distributions collected by 2D video disdrometer are considered to be fairly accurate within the typical sizes of drops. Vertical profiles of raindrop sizes up to 1085 m are estimated from the Doppler spectra measured by the micro rain radar with a height resolution of 35 m. Several issues related to vertical winds, attenuation correction, Doppler spectra aliasing, and range-Doppler ambiguity limit the performance of MRR in heavy precipitation or in convection, conditions that frequently occur in late summer or in autumn in Mediterranean regions. In this paper, MRR Doppler spectra are reprocessed, exploiting the 2DVD measurements at ground to estimate the effects of vertical winds at 105 m (the most reliable MRR lower height), in order to provide a better estimation of vertical profiles of raindrop size distribution from MRR spectra. Results show that the reprocessing procedure leads to a better agreement between the reflectivity computed at 105 m from the reprocessed MRR spectra and that obtained from the 2DVD data. Finally, vertical profiles of MRR-estimated RSDs and their relevant moments (namely median volume diameter and reflectivity) are presented and discussed in order to investigate the

  18. Vertical axis wind turbines

    DOEpatents

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  19. 2003 SOLAS Summer School

    NASA Technical Reports Server (NTRS)

    McGillis, Wade R.

    2003-01-01

    In 2003, the United States provided support for the participation of 18 students, three research assistants, and seven lecturers in the first international Surface Ocean Lower Atmosphere Study (SOLAS) Summer School. The purpose of this school was to introduce graduate students and young researchers to different components of SOLAS research including biogeochemical interactions and feedbacks, exchange processes, and air-sea fluxes. Support was provided through grants from: NASA (contact: Charles Trees); NSF (contact: Anne-Marie Schmoltner); NOAA (contact: Kathy Tedesco); and ONR (contact: Ronald Ferek).

  20. VERTICAL OZONE FLUXES AND RELATED DEPOSITION PARAMETERS OVER AGRICULTURAL AND FORESTED

    EPA Science Inventory

    The spatial variability and temporal behavior of the vertical flux of ozone has been investigated from turbulence measurements collected on aircraft flight legs in the daytime period during two consecutive summer experimental field studies. he data were obtained during horizontal...

  1. Assessment of Summer 1997 motor gasoline price increase

    SciTech Connect

    1998-05-01

    Gasoline markets in 1996 and 1997 provided several spectacular examples of petroleum market dynamics. The first occurred in spring 1996, when tight markets, following a long winter of high demand, resulted in rising crude oil prices just when gasoline prices exhibit their normal spring rise ahead of the summer driving season. Rising crude oil prices again pushed gasoline prices up at the end of 1996, but a warm winter and growing supplies weakened world crude oil markets, pushing down crude oil and gasoline prices during spring 1997. The 1996 and 1997 spring markets provided good examples of how crude oil prices can move gasoline prices both up and down, regardless of the state of the gasoline market in the United States. Both of these spring events were covered in prior Energy Information Administration (EIA) reports. As the summer of 1997 was coming to a close, consumers experienced yet another surge in gasoline prices. Unlike the previous increase in spring 1996, crude oil was not a factor. The late summer 1997 price increase was brought about by the supply/demand fundamentals in the gasoline markets, rather than the crude oil markets. The nature of the summer 1997 gasoline price increase raised questions regarding production and imports. Given very strong demand in July and August, the seemingly limited supply response required examination. In addition, the price increase that occurred on the West Coast during late summer exhibited behavior different than the increase east of the Rocky Mountains. Thus, the Petroleum Administration for Defense District (PADD) 5 region needed additional analysis (Appendix A). This report is a study of this late summer gasoline market and some of the important issues surrounding that event.

  2. Offset vertical radar profiling

    USGS Publications Warehouse

    Witten, A.; Lane, J.

    2003-01-01

    Diffraction tomography imaging was applied to VRP data acquired by vertically moving a receiving antenna in a number of wells. This procedure simulated a vertical downhole receiver array. Similarly, a transmitting antenna was sequentially moved along a series of radial lines extending outward from the receiver wells. This provided a sequence of multistatic data sets and, from each data set, a two-dimensional vertical cross-sectional image of spatial variations in wave speed was reconstructed.

  3. Vertical Axis Wind Turbine

    Energy Science and Technology Software Center (ESTSC)

    2002-04-01

    Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). VAWT-SAL Vertical Axis Wind Turbine- Stochastic Aerodynamic Loads Ver 3.2 numerically simulates the stochastic (random0 aerodynamic loads of the Vertical-Axis Wind Turbine (VAWT) created by the atomspheric turbulence. The program takes into account the rotor geometry, operating conditions, and assumed turbulence properties.

  4. Lack of Evidence for Laboratory and Natural Vertical Transmission of Bluetongue Virus in Culicoides sonorensis (Diptera: Ceratopogonidae)

    PubMed Central

    Mayo, C. E.; Mullens, B. A.; McDermott, E. G.; Gerry, A. C.; Reisen, W. K.; MacLachlan, N. J.

    2015-01-01

    Culicoides sonorensis (Wirth & Jones) is the principal North American vector of bluetongue virus (BTV). BTV infection of livestock is distinctly seasonal (late summer and fall) in temperate regions of the world such as California, which has led to speculation regarding vertical transmission of the virus within the midge vector as a potential mechanism for interseasonal maintenance (“overwintering”) of the virus. To evaluate potential vertical transmission of BTV in its midge vector, we fed adult midges BTV-spiked blood and used a BTV-specific quantitative reverse transcriptase polymerase chain reaction assay to evaluate parent, egg, and progeny stages of laboratory-reared C. sonorensis for the presence of viral nucleic acid. Whereas BTV nucleic acid was weakly detected in egg batches of virus-fed female midges, virus was never detected in subsequent progeny stages (larvae, pupae, and F1 generation adults). Similarly, BTV was not detected in pools of larvae collected from the waste-water lagoon of a BTV-endemic dairy farm in northern California during the seasonal period of virus transmission. Collectively, these results indicate that BTV is not readily transmitted vertically in C. sonorensis, and that persistence of the virus in long-lived parous female midges is a more likely mechanism for overwintering of BTV in temperate regions. PMID:26336312

  5. Lack of Evidence for Laboratory and Natural Vertical Transmission of Bluetongue Virus in Culicoides sonorensis (Diptera: Ceratopogonidae).

    PubMed

    Osborne, C J; Mayo, C E; Mullens, B A; McDermott, E G; Gerry, A C; Reisen, W K; MacLachlan, N J

    2015-03-01

    Culicoides sonorensis (Wirth & Jones) is the principal North American vector of bluetongue virus (BTV). BTV infection of livestock is distinctly seasonal (late summer and fall) in temperate regions of the world such as California, which has led to speculation regarding vertical transmission of the virus within the midge vector as a potential mechanism for interseasonal maintenance ("overwintering") of the virus. To evaluate potential vertical transmission of BTV in its midge vector, we fed adult midges BTV-spiked blood and used a BTV-specific quantitative reverse transcriptase polymerase chain reaction assay to evaluate parent, egg, and progeny stages of laboratory-reared C. sonorensis for the presence of viral nucleic acid. Whereas BTV nucleic acid was weakly detected in egg batches of virus-fed female midges, virus was never detected in subsequent progeny stages (larvae, pupae, and F1 generation adults). Similarly, BTV was not detected in pools of larvae collected from the waste-water lagoon of a BTV-endemic dairy farm in northern California during the seasonal period of virus transmission. Collectively, these results indicate that BTV is not readily transmitted vertically in C. sonorensis, and that persistence of the virus in long-lived parous female midges is a more likely mechanism for overwintering of BTV in temperate regions. PMID:26336312

  6. Summer-time salinity variability in the North Atlantic subtropical gyre; comparison of freshening events observed in June 2006 and in July-August 2012

    NASA Astrophysics Data System (ADS)

    Reverdin, G. P.; Morisset, S.; David, L.; Boutin, J.; Martin, N.; Marié, L.; Gaillard, F.; Centurioni, L. R.; Font, J.; Salvador, J.; Ward, B.; Diverrès, D.

    2012-12-01

    The largest surface salinity in the world ocean away from semi-enclosed seas is found in late summer in the North Atlantic subtropical gyre near 25-26°N 35-40°W, where it often exceeds 37.7 psu. This region is the site of the SPURS experiment. We examined all thermosalinograph data between 2002 and 2012 from two ships regularly crossing this region, the MN Colibri and MN Toucan. The data show that this region presents a minimum of spatial variability in summer, but is interspersed by occasional tongues of lower salinity, the best observed instance having happened in June 2006. In this case, we interpret the feature as advected from the north by southward currents in front of a high feature propagating to the west as Rossby waves. In the same region, recent salinity observations from instrumented drifters indicate occasional drops (by 0.3) in July and August 2012. We will discuss how advection and vertical stirring contribute to the surface salinity budget of these features. Data from the Strasse cruise surveys in August 2012 will be used to further diagnose the summer-time surface salinity budget in this region.

  7. Evaluation of a Summer Reading Program to Reduce Summer Setback

    ERIC Educational Resources Information Center

    Johnston, Jessica; Riley, Jessica; Ryan, Carey; Kelly-Vance, Lisa

    2015-01-01

    Summer setback, which is defined as a decline in academic achievement over the summer months, occurs in many academic areas but seems especially problematic in reading. We assessed students from a midwestern parochial school serving predominantly students from a low--socioeconomic status background for their reading achievement before they left…

  8. Super Summer Reader. 1991 Iowa Summer Library Program.

    ERIC Educational Resources Information Center

    Irving, Jan

    This manual presents information about Iowa's 1991 summer reading program, whose theme, "Super Summer Reader," celebrates both children and reading, as well as the "super people" found throughout history, in local communities, and in families. The manual contains a planning guide that is arranged by the following topics: scheduling, personnel,…

  9. Tsunami Summer! 2003 Young Adult Summer Library Program.

    ERIC Educational Resources Information Center

    Alabama Public Library Service, Montgomery.

    This manual is designed to assist public libraries in Alabama with setting up "Tsunami Summer!," a summer program for young adults, i.e., students in grades 6 through 12. The manual contains the following sections: (1) Publicity and Promotion; (2) Working with Schools; (3) Involving the Students, including teen volunteers, teen advisory councils,…

  10. Atlas of Japan (East) Sea hydrographic properties in summer, 1999

    NASA Astrophysics Data System (ADS)

    Talley, Lynne D.; Tishchenko, Pavel; Luchin, Vladimir; Nedashkovskiy, Alexander; Sagalaev, Sergey; Kang, Dong-Jin; Warner, Mark; Min, Dong-Ha

    2004-05-01

    Hydrographic properties from CTD and discrete bottle sample profiles covering the Japan (East) Sea in summer, 1999, are presented in vertical sections, maps at standard depths, maps on isopycnal surfaces, and as property-property distributions. This data set covers most of the Sea with the exception of the western boundary region and northern Tatar Strait, and includes nutrients, pH, alkalinity, and chlorofluorocarbons, as well as the usual temperature, salinity, and oxygen observations.

  11. Potential impacts of the Arctic on interannual and interdecadal summer precipitation over China

    SciTech Connect

    Li, Yuefeng; Leung, Lai-Yung R.

    2013-02-01

    After the end of the 1970s, there has been a tendency for enhanced summer precipitation over South China and the Yangtze River valley and drought over North China and Northeastern China. Coincidentally, Arctic ice concentration has decreased since the late 1970s, with larger reduction in summer than spring. However, the Arctic warming is more significant in spring than summer, suggesting that spring Arctic conditions could be more important in their remote impacts. This study investigates the potential impacts of the Arctic on summer precipitation in China. The leading spatial patterns and time coefficients of the unfiltered, interannual, and interdecadal precipitation (1960-2008) modes were analyzed and compared using empirical orthogonal function (EOF) analysis, which shows that the first three EOFs can capture the principal precipitation patterns (northern, central and southern patterns) over eastern China. Regression of the Arctic spring and summer temperature onto the time coefficients of the leading interannual and interdecadal precipitation modes shows that interdecadal summer precipitation in China is related to the Arctic spring warming, but the relationship with Arctic summer temperature is weak. Moreover, no notable relationships were found between the first three modes of interannual precipitation and Arctic spring or summer temperatures. Finally, correlations between summer precipitation and the Arctic Oscillation (AO) index from January to August were investigated, which indicate that summer precipitation in China correlates with AO only to some extent. Overall, this study suggests important relationships between the Arctic spring temperature and summer precipitation over China at the interdecadal time scale.

  12. Special Handbook: The Summer Scholar

    ERIC Educational Resources Information Center

    Thaler, Pat Koch; Shapiro, Sonya

    1978-01-01

    No longer is summer ushered in with that old "no more lessons, no more books" refrain. There are plenty of vacation learning opportunities--in and around New York, at college campuses, and even abroad--for all age groups. Here is a roundup of this summer's offerings. (Editor)

  13. Quality of Summer Teachers Examined

    ERIC Educational Resources Information Center

    Sawchuk, Stephen

    2011-01-01

    A hefty body of evidence documents the phenomenon of "summer learning loss," but consensus on the attributes of effective summer intervention, especially when it comes to access to high-quality teaching for students most at risk of falling behind, is only starting to emerge. Now, though, a handful of districts are beginning to wrestle with the…

  14. "Learning City" Summer Migrant Program.

    ERIC Educational Resources Information Center

    Presson, Johnny E.; Baker, Wilbur L.

    "Learning City" is the theme of a summer education project that provides a unique teaching atmosphere for migrant children. For 2 summers, 130 students have participated in this program that sustains and enforces reading and math skills, as well as helps develop self-concept. Industries in Learning City are the various branches of study: reading…

  15. Reverse Transfer Project, Summer 1986.

    ERIC Educational Resources Information Center

    Reis, Elizabeth

    In 1986, a Reverse Transfer Project was initiated at Moraine Valley Community College (MVCC) in order to promote the summer school attendance at MVCC of "reverse transfer" students (i.e., students who attended another institution during the regular academic year). A mailing, containing a cover letter, informational brochure, summer catalog, and…

  16. Evaluation of Summer Bridge Programs

    ERIC Educational Resources Information Center

    Garcia, Lisa D.; Paz, Chiara C.

    2009-01-01

    Many colleges and universities in the United States offer summer programs for their incoming students. While programs are structured and administered in a variety of ways and target various student populations, the most common type of summer bridge program aims to serve historically underrepresented students and students of low socioeconomic…

  17. On the linkage between the Asian summer monsoon and tropopause fold activity over the eastern Mediterranean and the Middle East

    NASA Astrophysics Data System (ADS)

    Tyrlis, Evangelos; Å kerlak, Bojan; Sprenger, Michael; Wernli, Heini; Zittis, George; Lelieveld, Jos

    2014-03-01

    A climatology of tropopause folds occurring over the Eastern Mediterranean and the Middle East (EMME) has been established using the ERA-Interim reanalyses for the years 1979-2012. The methodology employs an algorithm that detects folds at grid points where the vertical profile features multiple crossings of the dynamical tropopause and allows their classification according to their vertical extent. Our results confirm the findings of an earlier 1 year climatology that recognized a global "hot spot" of summertime fold activity between the eastern Mediterranean and central Asia, in the vicinity of the subtropical jet. Two distinct maxima of activity are identified over Turkey and Iran-Afghanistan where fold frequency exceeds 25%. Occasionally, medium and deep folds form over the two regions at surprisingly low latitudes. This summertime peak in fold activity diverges from the zonal mean seasonal cycle over the subtropics and is driven by the South Asian Monsoon. Starting in late spring, the EMME is gradually brought under the influence of the zonally asymmetric background state induced by the monsoon. As areas of sharply sloping isentropes develop especially over the eastern Mediterranean and Iran-Afghanistan, subsidence and fold formation are favored. Further investigation of the reanalysis data provided empirical evidence that the monsoon also drives the interannual variability of EMME fold activity. An upward trend in fold activity is identified, especially in May, attributed to the recent advanced monsoon onset and the deepening convective activity throughout summer, which promotes upper-level baroclinicity over the EMME and favors folding.

  18. Ozone vertical profile changes over South Pole

    NASA Technical Reports Server (NTRS)

    Oltmans, S. J.; Hofmann, D. J.; Komhyr, W. D.; Lathrop, J. A.

    1994-01-01

    Important changes in the ozone vertical profile over South Pole, Antarctica have occurred both during the recent period of measurements, 1986-1991, and since an earlier set of soundings was carried out from 1967-1971. From the onset of the 'ozone hole' over Antarctica in the early 1980s, there has been a tendency for years with lower spring ozone amounts to alternate with years with somewhat higher (although still depleted) ozone amounts. Beginning in 1989 there have been three consecutive years of strong depletion although the timing of the breakdown of the vortex has varied from year to year. Comparison of the vertical profiles between the two periods of study reveals the dramatic decreases in the ozone amounts in the stratosphere between 15-21 km during the spring. In addition, it appears that summer values are also now much lower in this altitude region.

  19. NEWS: AAPT Summer Meeting

    NASA Astrophysics Data System (ADS)

    Mellema, Steve

    2000-11-01

    The 2000 Summer Meeting of the American Association of Physics Teachers (AAPT) was held from 28~July-2~August at the University of Guelph in Ontario, Canada. Despite somewhat rainy weather throughout the week, the annual gathering was an enjoyable one, filled with interesting talks on the state of physics education in North America. Using a new scheduling format for the summer meeting, all of the paid workshops and tutorials were held on Saturday and Sunday 29-30 July. The invited and contributed papers for the main AAPT meeting were then presented on Monday, Tuesday and Wednesday. As had been done in 1999 in San Antonio, a two-day tandem meeting dedicated to Physics Education Research (PER) was held on Wednesday and Thursday 2-3 August, immediately after the main AAPT meeting. Over the three days of the main meeting, 60 sessions were held under the sponsorship of various AAPT committees. These included sessions (numbers in parentheses) organized by the committees on Apparatus (1), Astronomy Education (3), Awards (2), Computers (5), Graduate Education (2), High Schools (1), History and Philosophy (1), Instructional Media (3), International Education (1), Laboratories (2), Pre-High School Education (2), Programs (4), Professional Concerns (6), Research in Physics Education (8), Science Education for the Public (2), Two-Year Colleges (5), Undergraduate Education (7) and Women in Physics (4). Figure 1. Guelph Church of Our Lady. The main meeting opened on Sunday evening with an invited lecture by Dr John J Simpson from the host institution, the University of Guelph, describing the Sudbury Neutrino Observatory. At the ceremonial session that began the activities on Monday morning, recognition was given to Clifford Swartz for his almost 30 years of service as Editor of the AAPT journal, The Physics Teacher. This was followed by an invited talk by Jim Nelson from Seminole County Public School in Florida, who received the Excellence in Pre-College Teaching Award. The

  20. Climatology and dynamics of summer tropopause folds over the eastern Mediterranean and the Middle East

    NASA Astrophysics Data System (ADS)

    Tyrlis, E.; Skerlak, B.; Sprenger, M.; Wernli, H.; Zittis, G.; Lelieveld, J.

    2013-12-01

    A climatology of tropopause folds is presented that focus on the summer events occurring over the Eastern Mediterranean and the Middle East (EMME) based on the ERA-Interim dataset. The methodology employs an algorithm that detects folds as areas featuring multiple crossings of the dynamical tropopause and allows their classification according to their vertical extent. Our results confirm the findings of an earlier 1-year climatology that recognized a global ';hot spot' of fold activity over a sector extending from the eastern Mediterranean to Afghanistan, in the vicinity of the subtropical jet. Two distinct maxima of activity are recognized over Turkey and Iran-Afghanistan where fold occurrence exceeds 25%. Rarely, deep folds form over the Levantine Basin and Iran at surprising low latitudes. This summertime increase in fold activity defies the zonal mean seasonal cycle over the subtropics and it is driven by the South Asian Monsoon. From late spring, the EMME is gradually brought under the influence of the zonally asymmetric background state induced by the monsoon, which features an elevated tropopause and depression of isentropic surfaces. As areas of sharply sloping isentropes develop especially over the eastern Mediterranean and Iran-Afghanistan, subsidence and fold formation are favored. The monsoon also drives the interannual variability of EMME fold activity. An upward trend in fold activity is identified, especially during May that can be attributed to the recent advanced monsoon onset and the deeper convective activity throughout summer. This stronger upper level monsoon signature promotes enhanced upper level baroclinicity over the EMME that favors folding.

  1. Vertical sleeve gastrectomy

    MedlinePlus

    ... smaller stomach is about the size of a banana. It limits the amount of food you can ... staples. This creates a long vertical tube or banana-shaped stomach. The surgery does not involve cutting ...

  2. Micromachined electrostatic vertical actuator

    DOEpatents

    Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.; Krulevitch, Peter A.

    1999-10-19

    A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

  3. NEWS: AAPT Summer Meeting

    NASA Astrophysics Data System (ADS)

    Mellema, Steve

    2000-11-01

    The 2000 Summer Meeting of the American Association of Physics Teachers (AAPT) was held from 28~July-2~August at the University of Guelph in Ontario, Canada. Despite somewhat rainy weather throughout the week, the annual gathering was an enjoyable one, filled with interesting talks on the state of physics education in North America. Using a new scheduling format for the summer meeting, all of the paid workshops and tutorials were held on Saturday and Sunday 29-30 July. The invited and contributed papers for the main AAPT meeting were then presented on Monday, Tuesday and Wednesday. As had been done in 1999 in San Antonio, a two-day tandem meeting dedicated to Physics Education Research (PER) was held on Wednesday and Thursday 2-3 August, immediately after the main AAPT meeting. Over the three days of the main meeting, 60 sessions were held under the sponsorship of various AAPT committees. These included sessions (numbers in parentheses) organized by the committees on Apparatus (1), Astronomy Education (3), Awards (2), Computers (5), Graduate Education (2), High Schools (1), History and Philosophy (1), Instructional Media (3), International Education (1), Laboratories (2), Pre-High School Education (2), Programs (4), Professional Concerns (6), Research in Physics Education (8), Science Education for the Public (2), Two-Year Colleges (5), Undergraduate Education (7) and Women in Physics (4). Figure 1. Guelph Church of Our Lady. The main meeting opened on Sunday evening with an invited lecture by Dr John J Simpson from the host institution, the University of Guelph, describing the Sudbury Neutrino Observatory. At the ceremonial session that began the activities on Monday morning, recognition was given to Clifford Swartz for his almost 30 years of service as Editor of the AAPT journal, The Physics Teacher. This was followed by an invited talk by Jim Nelson from Seminole County Public School in Florida, who received the Excellence in Pre-College Teaching Award. The

  4. The Summer of Hydrogen

    NASA Technical Reports Server (NTRS)

    Weber, Philip

    2008-01-01

    Ground crew veterans at Kennedy Space Center still talk about what they call "the summer of hydrogen"-the long, frustrating months in 1990 when the shuttle fleet was grounded by an elusive hydrogen leak that foiled our efforts to fill the orbiter's external fuel tank. Columbia (STS-35) was on Launch Pad A for a scheduled May 30 launch when we discovered the hydrogen leak during - tanking. The external fuel tank is loaded through the orbiter. Liquid hydrogen flows through a 17-inch umbilical between the orbiter and the tank. During fueling, we purge the aft fuselage with gaseous nitrogen to reduce the risk of fire, and we have a leak-detection system in the mobile launch platform, which samples (via tygon tubing) the atmosphere in and around the vehicle, drawing it down to a mass spectrometer that analyzes its composition. When we progressed to the stage of tanking where liquid hydrogen flows through the vehicle, the concentration of hydrogen approached four percent-the limit above which it would be dangerously flammable. We had a leak. We did everything we could think of to find it, and the contractor who supplied the flight hardware was there every day, working alongside us. We did tanking tests, which involved instrumenting the suspected leak sources, and cryo-loaded the external tank to try to isolate precisely where the leak originated. We switched out umbilicals; we replaced the seals between the umbilical and the orbiter. We inspected the seals microscopically and found no flaws. We replaced the recirculation pumps, and we found and replaced a damaged teflon seal in a main propulsion system detent cover, which holds the prevalve-the main valve supplying hydrogen to Space Shuttle Main Engine 3 -in the open position. The seal passed leak tests at ambient temperature but leaked when cryogenic temperatures were applied. We added new leak sensors-up to twenty at a time and tried to be methodical in our placements to narrow down the possible sources of the problem

  5. Goddard Summer Interns: Andy Ryan

    NASA Video Gallery

    Andy Ryan is an intern staff assistant with the Lunar and Planetary Science Academy. This summer the LPSA traveled to the Channeled Scablands of eastern Washington to study and map the geology of t...

  6. The year without a summer

    NASA Astrophysics Data System (ADS)

    Luterbacher, J.; Pfister, C.

    2015-04-01

    The 1815 eruption of Tambora caused an unusually cold summer in much of Europe in 1816. The extreme weather led to poor harvests and malnutrition, but also demonstrated the capability of humans to adapt and help others in worse conditions.

  7. Goddard Summer Interns: Danielle Wood

    NASA Video Gallery

    Profile of Goddard intern Danielle Wood. Danielle is interning at Goddard in the Innovative Partnerships Program and at NASA Headquarters in the Office of the Chief Technologist in the summer of 20...

  8. Potentials Unlimited: A Summer Happening.

    ERIC Educational Resources Information Center

    Croskery, Beverly; Marten, Mary Elizabeth

    1980-01-01

    The article describes Potentials Unlimited, a summer camp program for gifted intermediate grade students in Cincinnati, Ohio. Aspects covered include priorities in selecting curricular activities and some of the camp activities themselves. (DLS)

  9. Summer climate of Madagascar and monsoon pulsing of its vortex

    NASA Astrophysics Data System (ADS)

    Jury, Mark R.

    2016-02-01

    This study analyzes the climate of Madagascar (12°-26°S, 43°-50°E) and its relation to the Indian Ocean during austral summer (Dec-Mar). Moisture converges onto a standing easterly wave and floods are prevalent in late summer. All-island daytime land temperatures exceed 38 °C in October and are ~4 °C above sea temperatures during summer. Analysis of thermally induced diurnal convection and circulation revealed inflow during the afternoon recirculated from the southeastern mountains and the warm Mozambique Channel. Summer rainfall follows latent and sensible heat flux during the first half of the day, and gains a surplus by evening via thunderstorms over the western plains. At the inter-annual time-scale, 2.3 years oscillations in all-island rainfall appear linked with the stratospheric quasi-biennial oscillation and corresponding 80 Dobson Unit ozone fluctuations during flood events. Wet spells at frequencies from 11-27 days derive from locally-formed tropical cyclones and NW-cloud bands. Flood case studies exhibit moisture recycling in the confluence zone between the sub-tropical anticyclone and the lee-side vortex. Hovmoller analysis of daily rainfall reinforces the concept of local generation and pulsing by cross-equatorial (Indian winter) monsoon flow rather than zonal atmospheric waves. Since the surface water budget is critical to agriculture in Madagascar, this study represents a further step to understand its meso-scale summer climate.

  10. Summer Final Report

    NASA Technical Reports Server (NTRS)

    Makidi, Nitou

    2012-01-01

    The summer of 2012 has been filled with many memorable events and activities. As an intern, I had responsibilities that had to be fulfilled. My tour of duty was completed as an administrative student trainee in the Information Technology and Communications Services Business Office (IT-A). In accordance with the Business Objectives and Agreement of the Business Office and my performance plan, I was to provide business office support, improve business, project management, and technical work processes. With this being stated, I supported a project called "The Big Move Project" (TBMP), which will take course over the next several years. The Big Move Project is the planning of the Information Technology (IT) Directorate's relocation to various buildings in the course of upcoming years, when designs and the building of Central Campus have been completed. Working directly with my supervisor and the project manager, I was responsible for gathering both administrative and operational area requirements for the Information Technology (IT) Directorate, along with its outsourced support and contractors, such as IMCS, NICS, and ACES. My first action was to create rubrics that will serve as a guideline for the information that should be given by each branch of IT. After receiving that information via a few KAITS actions, I was able to start the consolidation process, and begin working on a presentation. A SharePoint was created shortly after for others to view the progression of the project, which I managed. During the consolidation ofthis information, I would occasionally present to the IT Deputy Director and IT Chiefs. The draft of this presentation was shown to employees of Center Operations (T A) and stakeholders-IT Chief Officers and contractor managers-in the relocation of IT to make them aware of what requirements must be met that will enable IT to be accommodated appropriately in the design of Central Campus Phase 11-the time in which IT and its contractors are scheduled

  11. Changes in the relationship between Northeast China summer temperature and ENSO

    NASA Astrophysics Data System (ADS)

    Wu, Renguang; Yang, Song; Liu, Shi; Sun, Li; Lian, Yi; Gao, Zongting

    2010-11-01

    Northeast China (NEC) summer temperature tends to be lower (higher) than normal in El Niño (La Niña) developing years during 1950s through mid-1970s. The relationship between the NEC summer temperature and El Niño-Southern Oscillation (ENSO) is weakened or even becomes opposite in 1980s and 1990s. The present study documents this interdecadal change and investigates plausible reasons for this change. Before the late 1970s, ENSO affects the NEC summer temperature through modulating the South Asian heating and consequently the midlatitude Asian circulation. After the late 1970s, the connection between ENSO and the Indian summer monsoon and that between the South Asian heating and the midlatitude Asian circulation have been weakened. This leads to a weakening of ENSO impacts on the NEC summer temperature. It is found that the NEC summer temperature variations are closely related to the North Atlantic sea surface temperature (SST) and circulation changes in 1980s and 1990s. In particular, a tripole North Atlantic SST anomaly pattern in boreal spring is a good precursory for the NEC summer temperature anomalies. The NEC summer temperature displays a negative correlation with the summer SST surrounding the Maritime Continent in 1980s and 1990s. In many years, the tropical North Pacific and the North Atlantic SST anomalies can contribute in concert to the midlatitude Asian circulation changes and the NEC summer temperature anomalies. These effects overcome those of the central and eastern equatorial Pacific SST anomalies, leading to a same-sign relationship between the NEC summer temperature and the central and eastern equatorial Pacific SST anomalies.

  12. Warm summers during Younger Dryas cold reversal over Eurasia

    NASA Astrophysics Data System (ADS)

    Schenk, Frederik; Muschitiello, Francesco; Heikkilä, Miaja; Väliranta, Minna; Tarasov, Lev; Brandefelt, Jenny; Johansson, Arne; Näslund, Jens-Ove; Wohlfarth, Barbara

    2016-04-01

    The Younger Dryas cold reversal (GS-1) sticks out as a major stadial interrupting the mid to late deglaciation with a sharp temperature drop of several degrees around the North Atlantic with global teleconnections. The abrupt return to a very cold glacial-like ocean state introduces a strong temperature anomaly to the climate system contrasting the high solar radiation received by northern summers. Here we show that, in contrast to earlier coarse resolution climate simulations of the Younger Dryas, these competing factors result in rather warm summer conditions over Eurasia comparable to the preceding warm period of the late Allerød (GI-1a). Despite up to 10 K colder sea-surface-temperatures in summer, our high resolution simulation with the Community Earth System Model 1 (CESM1.0.5) suggests that the presence of large ice sheets over Scandinavia, Spitsbergen and the Kara Sea significantly modifies atmospheric flow in summer preventing cold westerly winds from the Atlantic to impact the continent. Instead, fluid dynamics around ice sheets deflect winds to the north or south along the coasts supported by divergent flow from ice domes, stratification and increased tendency to high pressure and atmospheric blocking. Consistent with our model simulation, we show that temperature reconstructions derived from an extended compilation of multi-proxy lake records (chironomids, aquatic pollen, macrofossils) suggest warm July conditions of 13-17° C for continental Europe with exception of coastal and high elevation sites. The analysis of simulated growing degree days, season length and first results from paleo lake modelling driven by climate model output suggests that severe winter to spring conditions significantly delay and shorten the vegetation season but do not produce cold summers as previously simulated.

  13. Changes in the association between summer temperature and mortality in Seoul, South Korea

    NASA Astrophysics Data System (ADS)

    Ha, Jongsik; Kim, Ho

    2013-07-01

    The health impact of climate change depends on various conditions at any given time and place, as well as on the person. Temporal variations in the relationship between high temperature and mortality need to be explored in depth to explain how changes in the level of exposure and public health interventions modify the temperature-mortality relationship. We examined changes in the relationship between human mortality and temperature in Seoul, which has the highest population in South Korea, considering the change in population structure from 1993-2009. Poisson regression models were used to estimate short-term temperature-related mortality impacts. Temperature-related risks were divided into two "time periods" of approximately equal length (1993 and 1995-2000, and 2001-2009), and were also examined according to early summer and late summer. Temperature-related mortality in summer over the past 17 years has declined. These decreasing patterns were stronger for cardiovascular disease-related mortality than for all non-accidental deaths. The novel finding is that declines in temperature-related mortality were particularly noteworthy in late summer. Our results indicate that temperature-related mortality is decreasing in Seoul, particularly during late summer and, to a lesser extent, during early summer. This information would be useful for detailed public health preparedness for hot weather.

  14. Vertical Seismoelectric Profiling

    NASA Astrophysics Data System (ADS)

    Araji, A.

    2011-12-01

    The seismoelectric method corresponds to the measurement of electromagnetic disturbances associated with the passage of seismic waves in a porous medium. The coupling is due to the existence of the electric double layer at the solid/water interfaces. We consider the case of vertical seismoelectric profiling in which we trigger a seismic source in a vertical borehole and measure the seismoelectric response on the surface. We aim to image hetrogeneities in that section of the subsurface by utilizing the seismoelectric sources created at interfaces. An iterative source localization inversion algorithm is used to achieve the imaging of interfaces.

  15. Winter/summer transition in the Antarctic mesopause region

    NASA Astrophysics Data System (ADS)

    Lübken, F.-J.; Höffner, J.; Viehl, T. P.; Becker, E.; Latteck, R.; Kaifler, B.; Murphy, D. J.; Morris, R. J.

    2015-12-01

    A new set of temperature data with unprecedented resolution and accuracy has been obtained from Fe lidar measurements at Davis, Antarctica (69°S). Here we concentrate on the months of the winter/summer transition (November to February) where we have collected a total of 1305 h of observations in the three seasons 2010/2011, 2011/2012, and 2012/2013. The temporal development of temperatures around the mesopause in 2012/2013 is rather similar to the Northern Hemisphere (NH), whereas the other seasons are significantly different, exhibiting, e.g., an unusual higher and colder mesopause around solstice (elevated summer mesopause). During this exceptional period mean daily mesopause heights and temperatures are approximately 92.0 ± 0.5 km and 125 K, respectively. The seasonal variation of temperatures in the mesopause region is closely related to the circulation in the stratosphere which exhibits an early (late) vortex breakdown in 2012/2013 (2010/2011). The situation is more complicated in 2011/2012. The early (late) transition in the mesopause region is accompanied by an early (late) appearance of polar mesosphere summer echoes. Zonal winds as measured by an MF radar also show systematic differences with westward winds reaching up to very high altitudes (nearly 100 km) for the late transition in 2010/2011 and to more common heights (˜90 km) for the early transition in 2012/2013. A mesopause being higher and colder compared to the NH (as occasionally observed at Davis) cannot be achieved by standard models. More sophisticated characterization of gravity wave forcing might be required.

  16. Vertical shaft windmill

    NASA Technical Reports Server (NTRS)

    Grana, D. C.; Inge, S. V., Jr. (Inventor)

    1983-01-01

    A vertical shaft has several equally spaced blades mounted. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.

  17. Aiding Vertical Guidance Understanding

    NASA Technical Reports Server (NTRS)

    Feary, Michael; McCrobie, Daniel; Alkin, Martin; Sherry, Lance; Polson, Peter; Palmer, Everett; McQuinn, Noreen

    1998-01-01

    A two-part study was conducted to evaluate modern flight deck automation and interfaces. In the first part, a survey was performed to validate the existence of automation surprises with current pilots. Results indicated that pilots were often surprised by the behavior of the automation. There were several surprises that were reported more frequently than others. An experimental study was then performed to evaluate (1) the reduction of automation surprises through training specifically for the vertical guidance logic, and (2) a new display that describes the flight guidance in terms of aircraft behaviors instead of control modes. The study was performed in a simulator that was used to run a complete flight with actual airline pilots. Three groups were used to evaluate the guidance display and training. In the training, condition, participants went through a training program for vertical guidance before flying the simulation. In the display condition, participants ran through the same training program and then flew the experimental scenario with the new Guidance-Flight Mode Annunciator (G-FMA). Results showed improved pilot performance when given training specifically for the vertical guidance logic and greater improvements when given the training and the new G-FMA. Using actual behavior of the avionics to design pilot training and FMA is feasible, and when the automated vertical guidance mode of the Flight Management System is engaged, the display of the guidance mode and targets yields improved pilot performance.

  18. Vertical Alignment and Collaboration.

    ERIC Educational Resources Information Center

    Bergman, Donna; Calzada, Lucio; LaPointe, Nancy; Lee, Audra; Sullivan, Lynn

    This study investigated whether vertical (grade level sequence) alignment of the curriculum in conjunction with teacher collaboration would enhance student performance on the Texas Assessment of Academic Skills (TAAS) test in south Texas school districts of various sizes. Surveys were mailed to the office of the superintendent of 47 school…

  19. Life history and vertical distribution of the mesopelagic fish Cyclothone alba (family Gonostomatidae) in Sagami Bay, Central Japan

    NASA Astrophysics Data System (ADS)

    Miya, Masaki; Nemoto, Takahisa

    1986-08-01

    Life history and vertical distribution of the mesopelagic fish Cyclothone alba (family Gonostomatidae) are described on the basis of over 4000 specimens taken during a series of 15 cruises from December 1982 to December 1984 at a station near the center of Sagami Bay, Central Japan. C. alba does not undertake diel vertical migrations, being concentrated in the mesopelagic zone between 300 and 500 m, with peak abundance at 350 m both day and night. Spawning occurs mainly during the late spring and summer months in Sagami Bay. C. alba is semelparous, releasing about 200-650 eggs at the end of its life. Duration of the egg and larval stages is estimated to be about 2-3 months. Many males and some females mature at 1 year, and all individuals mature by 2 years of age. Sexual dimorphism in smaller males and larger females results from an earlier decline of growth rate in males: on the average, males reach 17.5 mm SL (standard length) in 1 year and 21 mm SL in 2 years, whereas females reach 19 mm SL in 1 year and 26 mm SL in 2 years. It is suggested that such precocious maturation, together with its small larvalized form, is attained through progenesis.

  20. Hottest summers the new normal

    NASA Astrophysics Data System (ADS)

    Camargo, Suzana J.; Seth, Anji

    2016-08-01

    With the rise in temperature due to anthropogenic climate change, the occurrence of hot summers, temperature extremes and heat waves is increasing globally. Projections for the coming decades to century indicate increases in the occurrence, magnitude and duration of these events. In a recent paper, Mueller et al (2016 Environ. Res. Lett. 11 044011) showed that half of summers are expected to be ‘hot’ (warmer than the warmest on record) across much of the world in one or two decades. While these results are consistent with earlier work, what is new here includes (i) an earlier timing of emergence of the hot summer signal and (ii) additional confidence due to the rigorous statistical examination of the observations and the analyses of the latest improved suite of model experiments. The potential impacts of these projections on society are extremely serious.

  1. Summer Fun in the Sun

    NASA Astrophysics Data System (ADS)

    Alexander, D.; Noldon, D.

    2002-05-01

    We report here on the development of a program to incorporate a math/science component, emphasizing space science and solar physics, into an existing set of summer activities sponsored by the National Youth Sports Program (NYSP). NYSP provides summer sports and classroom training components to youth whose families fall within federal poverty guidelines. Recently, a partnership between Lockheed Martin Solar and Astrophysics Lab. and Chabot Community College received NASA IDEAS funding to develop a summer curriculum in math and science to augment the already successful program. This provides an opportunity to significantly enhance the experience of the participating students by giving them access to the latest in space data and direct interaction with space scientists. This paper discusses our goals, our approach and the current status of our curricular materials. We would like to acknowledge funding by the National Youth Sports Program and NASA IDEAS.

  2. Summer Ice and Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Kukla, G.; Gavin, J.

    1981-10-01

    The extent of Antarctic pack ice in the summer, as charted from satellite imagery, decreased by 2.5 million square kilometers between 1973 and 1980. The U.S. Navy and Russian atlases and whaling and research ship reports from the 1930's indicate that summer ice conditions earlier in this century were heavier than the current average. Surface air temperatures along the seasonally shifting belt of melting snow between 55 degrees and 80 degrees N during spring and summer were higher in 1974 to 1978 than in 1934 to 1938. The observed departures in the two hemispheres qualitatively agree with the predicted impact of an increase in atmospheric carbon dioxide. However, since it is not known to what extent the changes in snow and ice cover and in temperature can be explained by the natural variability of the climate system or by other processes unrelated to carbon dioxide, a cause-and-effect relation cannot yet be established.

  3. Summer ice and carbon dioxide

    SciTech Connect

    Kukla, G.; Gavin, J.

    1981-10-30

    The extent of Antarctic pack ice in the summer, as charted from satellite imagery, decreased by 2.5 million square kilometers between 1973 and 1980. The U.S. Navy and Russian atlases and whaling and reseach ship reports from the 1930's indicate that summer ice conditions earlier in this century were heavier than the current average. Surface air temperatures along the seasonally shifting belt of melting snow between 55/sup o/ and 80/sup o/N during spring and summer were higher in 1974 to 1978 than in 1934 to 1938. The observed departures in the two hemispheres qualitatively agree with the predicted impact of an increase in atmospheric carbon dioxide. However, since it is not known to what extent the changes in snow and ice cover and in temperature can be explained by the natural variability of the climate system or by other processes unrelated to carbon dioxide, a cause-and-effect relation cannot yet be established.

  4. Gibberellic acid (GA3) effects on late season grapefruit peel oil composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gibberellic acid (GA3) is commonly applied to citrus fruit in the late summer/early autumn to delay peel maturation and extend late season quality. The effect of August/September GA3 application on oil gland composition of "Marsh" white grapefruit harvested in March 18 and April 16 from three groves...

  5. Think Summer: Early Planning, Teacher Support Boost Summer Learning Programs

    ERIC Educational Resources Information Center

    Browne, Daniel

    2013-01-01

    A fundamental problem that continues to plague educators is the achievement gap between low-income and higher-income students. In the ongoing search for solutions, one of the more promising approaches is expanding opportunities for learning, particularly in the summer. This article describes a project funded by The Wallace Foundation that offers…

  6. 1998 Complex Systems Summer School

    SciTech Connect

    1998-12-15

    For the past eleven years a group of institutes, centers, and universities throughout the country have sponsored a summer school in Santa Fe, New Mexico as part of an interdisciplinary effort to promote the understanding of complex systems. The goal of these summer schools is to provide graduate students, postdoctoral fellows and active research scientists with an introduction to the study of complex behavior in mathematical, physical, and living systems. The Center for Nonlinear Studies supported the eleventh in this series of highly successful schools in Santa Fe in June, 1998.

  7. Late Glacial and Late Holocene Paleohydrology of Central Asia

    NASA Astrophysics Data System (ADS)

    Aichner, B.; Feakins, S. J.; Mischke, S.; Herzschuh, U.; Liu, X.; Rajabov, I.; Wang, Y.; Heinecke, L.

    2013-12-01

    The goal of this study is to deepen the understanding of past climatological, ecological and hydrological changes in Central Asia, by means of organic geochemical proxies and in close cooperation with other work groups providing biological and sedimentological data. We analysed an 8 m sediment core from Lake Karakuli, a small open freshwater lake situated at an altitude of 3,657 m between the massifs of Muztagh Ata (7,546 m) and Kongur Shan (7,719 m) in western China. Additional work is in progress on a 12 m core derived from Lake Karakul in Tajikistan, a large closed saline lake situated in a tectonic graben structure at an altitude of 3,928 m. The distance between the two lakes is 130 km and basal ages of the cores are ca. 4.7 ka BP (China) and ca. 27 ka BP (Tajikistan). The lake catchments may be classified as alpine steppe to alpine deserts with mean annual temperature of ca. 0 °C and mean annual precipitation of ca. 100 mm, respectively. Summer precipitation, associated with the Indian monsoon, accounts for <30% of the annual total, whereas most precipitation is supplied by mid-latitude Westerlies between March and May. In the small Chinese lake long-chain fatty acids (FAs) were mainly attributed to terrestrial sources by compound-specific carbon isotopic analyses. In contrast δ13C values up to -14‰ for abundant mid-chain FAs suggest aquatic origins in the large Lake Karakul. Hydrogen isotopic variability is ca. 15‰ in the mid-Holocene record and ca. 60‰ in the first data derived from the Late Glacial record. In the latter, the most pronounced change from higher to lower δD-values of aquatic biomarkers is tentatively interpreted as change from arid to more humid conditions at the Late Glacial to Holocene transition. Since in Central Asia isotopic variability of precipitation mainly correlates with temperature, we interpret high resolution δD data of terrestrial long-chain FAs in the younger core to mainly reflect mid-Holocene temperature variations

  8. Water deficit and induction of summer dormancy in perennial Mediterranean grasses

    PubMed Central

    Volaire, Florence; Seddaiu, Giovanna; Ledda, Luigi; Lelievre, François

    2009-01-01

    Background and Aims Summer dormancy is a trait conferring superior drought survival in Mediterranean perennial grasses. As the respective roles of environmental factors and water deficit on induction of summer dormancy are unclear, the effect of intense drought were tested under contrasting day lengths in a range of forage and native grasses. Methods Plants of Poa bulbosa, Dactylis glomerata ‘Kasbah’ and Lolium arundinaceum ‘Flecha’ were grown in pots (a) from winter to summer in a glasshouse and subjected to either an early or a late-spring drought period followed by a summer water deficit and (b) in controlled conditions, with long days (LD, 16 h) or short days (SD, 9 h) and either full irrigation or water deficit followed by rehydration. Leaf elongation, senescence of aerial tissues and dehydration of basal tissues were measured to assess dormancy. Endogenous abscisic acid (ABA) in basal tissues was determined by monoclonal immunoassay analysis. Key Results Even under irrigation, cessation of leaf elongation, senescence of lamina and relative dehydration of basal tissues were triggered only by a day length longer than 13 h 30 min (late spring and LD) in plants of Poa bulbosa and Dactylis glomerata ‘Kasbah’ which exhibit complete dormancy. Plants of Lolium arundinaceum ‘Flecha’ maintained leaf growth under irrigation irrespective of the day length since its dormancy is incomplete. ABA concentrations were not higher during late-spring drought than early, and could not be associated with spring dormancy induction. In summer, ABA concentration in bulbs of the desiccation-tolerant Poa were greater than in basal tissues of other species. Conclusions The results of both experiments tend to invalidate the hypothesis that water deficit has a role in early summer-dormancy induction in the range of tested grasses. However, a late-spring drought tends to increase plant senescence and ABA accumulation in basal tissues of forage grasses which could enhance

  9. Investigation of summer monsoon rainfall variability in Pakistan

    NASA Astrophysics Data System (ADS)

    Hussain, Mian Sabir; Lee, Seungho

    2016-08-01

    This study analyzes the inter-annual and intra-seasonal rainfall variability in Pakistan using daily rainfall data during the summer monsoon season (June to September) recorded from 1980 to 2014. The variability in inter-annual monsoon rainfall ranges from 20 % in northeastern regions to 65 % in southwestern regions of Pakistan. The analysis reveals that the transition of the negative and positive anomalies was not uniform in the investigated dataset. In order to acquire broad observations of the intra-seasonal variability, an objective criterion, the pre-active period, active period and post-active periods of the summer monsoon rainfall have demarcated. The analysis also reveals that the rainfall in June has no significant contribution to the increase in intra-seasonal rainfall in Pakistan. The rainfall has, however, been enhanced in the summer monsoon in August. The rainfall of September demonstrates a sharp decrease, resulting in a high variability in the summer monsoon season. A detailed examination of the intra-seasonal rainfall also reveals frequent amplitude from late July to early August. The daily normal rainfall fluctuates significantly with its maximum in the Murree hills and its minimum in the northwestern Baluchistan.

  10. Investigation of summer monsoon rainfall variability in Pakistan

    NASA Astrophysics Data System (ADS)

    Hussain, Mian Sabir; Lee, Seungho

    2016-01-01

    This study analyzes the inter-annual and intra-seasonal rainfall variability in Pakistan using daily rainfall data during the summer monsoon season (June to September) recorded from 1980 to 2014. The variability in inter-annual monsoon rainfall ranges from 20 % in northeastern regions to 65 % in southwestern regions of Pakistan. The analysis reveals that the transition of the negative and positive anomalies was not uniform in the investigated dataset. In order to acquire broad observations of the intra-seasonal variability, an objective criterion, the pre-active period, active period and post-active periods of the summer monsoon rainfall have demarcated. The analysis also reveals that the rainfall in June has no significant contribution to the increase in intra-seasonal rainfall in Pakistan. The rainfall has, however, been enhanced in the summer monsoon in August. The rainfall of September demonstrates a sharp decrease, resulting in a high variability in the summer monsoon season. A detailed examination of the intra-seasonal rainfall also reveals frequent amplitude from late July to early August. The daily normal rainfall fluctuates significantly with its maximum in the Murree hills and its minimum in the northwestern Baluchistan.