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Sample records for global temperature variation

  1. Global temperature variations

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1993-01-01

    Lower stratospheric temperature anomalies from MSU channel 4 were compared to ten years of radiosonde data to validate the satellite record, and the results were submitted for publication. Various assumed stratospheric weighting profiles were tested to determine whether the theoretical channel 4 weighting function had significant errors. It was found that the real weighting function is slightly sharper than the theoretical weighting function. We also found evidence for a step-function cooling in the radiosonde record during 1982, a period when two satellites were operating with no evidence of changes in the satellites. Lower tropospheric bulk temperature datasets continue to be sent to climate researchers and modelers, as well as to the Climate Analysis Center (CAC). The CAC is also implementing our MSU software to be able to do the MSU processing at their site. Drift in MSU channel 3 is being quantified and corrected to allow it to be used together with channel 2 for a better lowertropospheric gridpoint temperature product. A new global oceanic precipitation dataset has been produced from MSU channel 1 data, and compared to ten years of global raingage data.

  2. Global temperature variations

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1991-01-01

    Intercalibration statistics of all Microwave Sounding Units (MSUs) operating through 1990 were computed and brightness temperature anomalies on various space and time scales were compiled for MSU channels 2 (troposphere) and 4 (lower stratosphere). A tropospheric retrieval was developed through combination of channel 2 data from various view angles across the MSU scan swath to achieve cancellation of the influence of the lower stratosphere, and much of the upper troposphere, on that channel. Radiosonde validation of the MSU channel 2 and tropospheric retrieval anomalies was performed with 10 years of data at all U.S. controlled stations.

  3. Variational global analysis of satellite temperature soundings

    NASA Technical Reports Server (NTRS)

    Halem, M.; Kalnay, E.

    1983-01-01

    A variational spherical harmonic analysis is developed for the production of global geopotential height and geostropic wind fields from the TIROS-N spacecraft's temperature sounding profiles. This scheme is based on Tykhonov's (1964) regularization method, and the smoothing parameter is determined by cross validation. The scheme is noted to be stable and computationally efficient, and it does not depend on a priori information. Its applications to three-dimensional temperature retrievals and to four-dimensional spectral analyses are illustrated.

  4. Modulation of fossil fuel production by global temperature variations, 2

    SciTech Connect

    Rust, B.W.; Crosby, F.J.

    1994-01-01

    The report includes the inverse modulation of global fossil production by variations in Northern Hemispheric temperatures. The present study incorporates recent revisions and extensions of the fuel production record and uses a much improved temperature record. The authors show that the new data are consistent with the predictions of the original Rust-Kirk model which they then extend to allow for time lag between variations in the temperature and the corresponding responses in fuel production. The modulation enters the new model through the convolution of a lagged averaging function with the temperature time-series. The authors also include explicit terms to account for the perturbations caused by the Great Depression and World War II. The final model accounts for 99.84% of the total variance in the production record. This modulation represents a feedback which is consistent with the carbon dioxide problem; climate change; fossil fuel production; global warming Gaia hypothesis; temperature variations.

  5. Global patterns of cloud optical thickness variation with temperature

    NASA Technical Reports Server (NTRS)

    Tselioudis, George; Rind, David; Rossow, William B.

    1990-01-01

    A global cloud climatology dataset is used to study patterns of cloud optical thickness variation with temperature. The data, which cover the period from July 1983 through June 1995, contain detailed information on the distribution of cloud radiative properties and their diurnal and seasonal variations, as well as information on the vertical distribution of temperature and humidity in the troposphere. For cold low clouds over land, the temperature coefficient of change in optical thickness has a value of about 0.04, which is similar to that deduced from Soviet aircraft observations and derived from thermodynamic considerations for the change of cloud liquid water with temperature. It is suggested that, in this cold-temperature range, cloud optical thickness variations are dominated by changes in the liquid water content of the cloud and that the liquid water content changes in accordance with the thermodynamic theory.

  6. Global patterns of cloud optical thickness variation with temperature

    NASA Technical Reports Server (NTRS)

    Tselioudis, George; Rind, David; Rossow, William B.

    1990-01-01

    A global cloud climatology dataset is used to study patterns of cloud optical thickness variation with temperature. The data, which cover the period from July 1983 through June 1995, contain detailed information on the distribution of cloud radiative properties and their diurnal and seasonal variations, as well as information on the vertical distribution of temperature and humidity in the troposphere. For cold low clouds over land, the temperature coefficient of change in optical thickness has a value of about 0.04, which is similar to that deduced from Soviet aircraft observations and derived from thermodynamic considerations for the change of cloud liquid water with temperature. It is suggested that, in this cold-temperature range, cloud optical thickness variations are dominated by changes in the liquid water content of the cloud and that the liquid water content changes in accordance with the thermodynamic theory.

  7. Global patterns of cloud optical thickness variation with temperature

    SciTech Connect

    Tselioudis, G.; Rossow, W.B.; Rind, D. )

    1992-12-01

    The International Satellite Cloud Climatology Project (ISCCP) dataset is used to correlate variations of cloud optical thickness and cloud temperature in today's atmosphere. The analysis focuses on low clouds in order to limit the importance of changes in cloud vertical extent, particle size, and water phase. Coherent patterns of change are observed on several time and space scales. On the planetary scale, clouds in colder, higher latitudes are found to be optically thicker than clouds in warmer, lower latitudes. On the seasonal scale, winter clouds are, for the most part, optically thicker than summer clouds. The logarithmic derivative of cloud optical thickness with temperature is used to describe the sign and magnitude of the optical thickness - temperature correlation. The seasonal, latitudinal, and day-to-day variations of this relation are examined for Northern Hemisphere clouds in 1984. The analysis is done separately for clouds over land and ocean. In cold continental clouds, optical thickness increases with temperature, consistent with the temperature variation of the adiabatic cloud water content. In warm continental and in almost all maritime clouds, however, optical thickness decreases with temperature. The behavior of the optical thickness-temperature relation is usually, though not always, the same whether the temperature variations are driven by seasonal, latitudinal, or day-to-day changes. Important exceptions are noted. Some explanations for the observed behavior are proposed. 43 refs., 8 figs.

  8. Global patterns of cloud optical thickness variation with temperature

    NASA Technical Reports Server (NTRS)

    Tselioudis, George; Rossow, William B.; Rind, David

    1992-01-01

    The International Satellite Cloud Climatology Project dataset is used to correlate variations of cloud optical thickness and cloud temperature in today's atmosphere. The analysis focuses on low clouds in order to limit the importance of changes in cloud vertical extent, particle size, and water phase. Coherent patterns of change are observed on several time and space scales. On the planetary scale, clouds in colder, higher latitudes are found to be optically thicker than clouds in warmer, lower latitudes. On the seasonal scale, winter clouds are, for the most part, optically thicker than summer clouds. The logarithmic derivative of cloud optical thickness with temperature is used to describe the sign and magnitude of the optical thickness-temperature correlation. The seasonal, latitudinal, and day-to-day variations of this relation are examined for Northern Hemisphere clouds in 1984. In cold continental clouds, optical thickness increases with temperature, consistent with the temperature variation of the adiabatic cloud water content. In warm continental and in almost all maritime clouds, however, optical thickness decreases with temperature.

  9. Spatial correlations of interdecadal variation in global surface temperatures

    NASA Technical Reports Server (NTRS)

    Mann, Michael E.; Park, Jeffrey

    1993-01-01

    We have analyzed spatial correlation patterns of interdecadal global surface temperature variability from an empirical perspective. Using multitaper coherence estimates from 140-yr records, we find that correlations between hemispheres are significant at about 95 percent confidence for nonrandomness for most of the frequency band in the 0.06-0.24 cyc/yr range. Coherence estimates of pairs of 100-yr grid-point temperature data series near 5-yr period reveal teleconnection patterns consistent with known patterns of ENSO variability. Significant correlated variability is observed near 15 year period, with the dominant teleconnection pattern largely confined to the Northern Hemisphere. Peak-to-peak Delta-T is at about 0.5 deg, with simultaneous warming and cooling of discrete patches on the earth's surface. A global average of this pattern would largely cancel.

  10. Global circuit response to seasonal variations in global surface air temperature

    NASA Technical Reports Server (NTRS)

    Williams, Earle R.

    1994-01-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  11. Global circuit response to seasonal variations in global surface air temperature

    SciTech Connect

    Williams, E.R.

    1994-08-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  12. Global circuit response to seasonal variations in global surface air temperature

    NASA Technical Reports Server (NTRS)

    Williams, Earle R.

    1994-01-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  13. Global surface air temperature variations: 1851-1984

    SciTech Connect

    Jones, P.D.; Raper, S.C.B.; Kelly, P.M.

    1986-11-01

    Many attempts have been made to combine station surface air temperature data into an average for the Northern Hemisphere. Fewer attempts have been made for the Southern Hemisphere because of the unavailability of data from the Antarctic mainland before the 1950s and the uncertainty of making a hemispheric estimate based solely on land-based analyses for a hemisphere that is 80% ocean. Past estimates have been based largely on data from the World Weather Records (Smithsonian Institution, 1927, 1935, 1947, and U.S. Weather Bureau, 1959-82) and have been made without considerable effort to detect and correct station inhomogeneities. Better estimates for the Southern Hemisphere are now possible because of the availability of 30 years of climatological data from Antarctica. The mean monthly surface air temperature anomalies presented in this package for the than those previously published because of the incorporation of data previously hidden away in archives and the analysis of station homogeneity before estimation.

  14. Application of a global variational analysis to quasi three-dimensional temperature retrievals

    NASA Technical Reports Server (NTRS)

    Dalcher, A.; Kalnay, E.; Halem, M.

    1983-01-01

    The Halen and Kalnay (1983) hypothesis that the application of global variational analysis to clear column radiances will result in a reduction of both observational noise and data gaps is tested, together with the hypothesis of these authors that the estimate of clear column radiances furnished by the variational analysis can yield a useful reduction of the data gaps in the retrieved temperatures. In the first of two experiments conducted, attention is given to whether the nonlinearity of the temperature retrieval method is sufficiently strong to result in more accurate temperature retrievals. In the second experiment, realistic subgrid scale cloud fields and observational and temperature errors are included in the simulation system.

  15. Long-term global temperature variations under total solar irradiance, cosmic rays, and volcanic activity.

    PubMed

    Biktash, Lilia

    2017-07-01

    The effects of total solar irradiance (TSI) and volcanic activity on long-term global temperature variations during solar cycles 19-23 were studied. It was shown that a large proportion of climate variations can be explained by the mechanism of action of TSI and cosmic rays (CRs) on the state of the lower atmosphere and other meteorological parameters. The role of volcanic signals in the 11-year variations of the Earth's climate can be expressed as several years of global temperature drop. Conversely, it was shown that the effects of solar, geophysical, and human activity on climate change interact. It was concluded that more detailed investigations of these very complicated relationships are required, in order to be able to understand issues that affect ecosystems on a global scale.

  16. Long-term global temperature variations under the influence of different cosmophysical factors

    NASA Astrophysics Data System (ADS)

    Biktash, Lilia

    2016-07-01

    We have analyzed different cosmophysical factors which have effect on long-term global temperature variations during solar cycles 20-24. A detailed analysis of total solar irradiance (TSI), the spectral solar ultraviolet emission (UV), space weather and cosmic rays (CRs) have effects on the atmosphere processes. We have shown that increasing of global temperature is likely affected by TSI and UV during solar maxima. During the descending phases of these solar cycles the interplanetary magnetic field and long-lasting solar wind high speed streams occurred frequently and were the primary contributors to minimize of CRs effect on the Earth's atmosphere. In this case global temperature is increased extra as result of increase in the atmosphere's transparency. We show that there are a few effective physical mechanisms of the action of solar activity and space weather on the global temperature. TSI and CRs play essential role in climate change and main part of climate variations can be explained by the mechanism of action TSI and CRs modulated by the solar activity on the state of lower atmosphere and meteorological parameters.

  17. Further studies on the modulation of fossil fuel production by global temperature variations

    SciTech Connect

    Rust, B.W.; Crosby, F.J. )

    1994-01-01

    This study extends the earlier work of Rust and Kirk (1982) on the inverse modulation of global fossil fuel production by variations in Northern Hemispheric temperatures. Recent revisions and extensions of the fuel production record are incorporated and a much improved temperature record in used. The new data are consistent with the predictions of the original Rust-Kirk model which is extended to allow for time lags between variations in the temperature and the corresponding responses in fuel production. The modulation enters the new model through the convolution of a lagged averaging function with the temperature time-series. Explicit terms account for the perturbations caused by the Great Depression and World War II. The final model accounts for 99.84% of the total variance in the production record. The temperature modulation produces variations of as much as 30% in the total production. This modulation represents a feedback which is consistent with the predictions of the Gaia hypothesis for a planetary greenhouse temperature control. The new model calculates 20-y fuel production predictions for three temperature scenarios which hopefully bracket the possibilities for temperature behavior during that time.

  18. Global and Hemispheric Annual Temperature Variations Between 1854 and 1991 (revised 1994) (NDP-022)

    DOE Data Explorer

    Jones, P. D.; Wigley, T. M. L.; Wright, P. B.

    1994-01-01

    This data set contains estimates of global and hemispheric annual temperature variations, relative to a 1950 through 1979 reference period, for 1861 through 1991. The estimates are based on corrected land and ocean data. Land data were derived from meteorological data and fixed-position weather-ship data that were corrected for nonclimatic errors, such as station shifts and/or instrument changes. The marine data used were those in the Comprehensive Ocean-Atmosphere Data Set (COADS) compilation, which with updates covers to 1986. Updates to 1991 were made with hemispheric sea-surface temperature estimates produced by the U.K. Meteorological Office. Each record includes year and six annual temperature variations: one estimate each for the globe, the Northern Hemisphere, and the Southern Hemisphere and another estimate each that reflects an adjustment to account for the influence of El Niño/Southern Oscillation events. The data are in one file of 13 kB.

  19. Numerical simulation of global variations of temperature, ozone, and trace species in the stratosphere

    SciTech Connect

    Smith, A.K.

    1995-01-01

    A three-dimensional dynamical chemical model of the middle atmosphere is used to examine the global response to planetary waves in the middle and high latitudes of the northern hemisphere. The model indicates that larger wave activity in the lower stratosphere at 60 deg N is correlated with decreasing zonal mean temperatures throughout the tropical and summer hemisphere stratosphere as a result of an induced global-scale circulation. The tendency of mean ozone is positively correlated with the temperature tendency in the lower stratosphere and negatively correlated in the upper stratosphere. In the upper stratosphere, the anticorrelation of mean ozone and temperature is due primarily to the temperature dependence of many of the reaction rates. The quantitative agreement of the model results with available observations is better when the dependence of the ozone-temperature relation on the mean zone amount is removed (by taking the log of ozone) because the model ozone differs from the observed. A model run in which the atmospheric chlorine is removed indicates that the magnitude of the ozone change for a given temperature change can be substantial for modifications in the model photochemistry. Another run tested a more realistic change in which a key reaction rate is modified; the results indicate differences of greater than 10% in the ratio of ozone to temperature changes. With improved measurement capabilities differences of this order may now or soon be detectable. The variations of other chemical species in the model with temperature are also presented.

  20. Solar total irradiance variations and the global sea surface temperature record

    SciTech Connect

    Reid, G.C. Univ. of Colorado, Boulder )

    1991-02-20

    The record of globally averaged sea surface temperature (SST) over the past 130 years shows a highly significant correlation with the envelope of the 11-year cycle of solar activity over the same period. This correlation could be explained by a variation in the sun's total irradiance (the solar constant) that is in phase with the solar-cycle envelope, supporting and updating an earlier conclusion by Eddy (1976) that such variations could have played a major role in climate change over the past millennium. Measurements of the total irradiance from spacecraft, rockets, and balloons over the past 25 years have provided evidence of long-term variations and have been used to develop a simple linear relationship between irradiance and the envelope of the sunspot cycle. This relationship has been used to force a one-dimensional model of the thermal structure of the ocean, consisting of a 100-m mixed layer coupled to a deep ocean and including a thermohaline circulation. The model was started in the mid-seventeenth century, at the time of the Maunder Minimum of solar activity, and mixed-layer temperatures were calculated at 6-month intervals up to the present. The total range of irradiance values during the period was about 1%, and the total range of SST was about 1C. Cool periods, when temperatures were about 0.5C below present-day values, were found in the early decades of both the nineteenth and twentieth centuries. The results can be taken as indicating that solar variability has been an important contributor to global climate variations in recent decades. The growing atmospheric burden of greenhouse gases may well have played an important role in the immediate past.

  1. Statistical examination of climatological data relevant to global temperature variation. Final report

    SciTech Connect

    Gray, H.L.; Gunst, R.F.; Woodward, W.A.

    1998-07-01

    Advanced statistical procedures have been developed to analyze and model climatological data. Research has focused on the following areas: testing the global temperature series for trend; the effect of initial conditions on autoregressive models for global temperature data; long memory modeling of the carbon dioxide data; and spatial modeling of global temperature data.

  2. Global characteristics in the diurnal variations of the thermospheric temperature and composition

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Hedin, A. E.; Reber, C. A.; Carignan, G. R.

    1973-01-01

    Global characteristics in the diurnal components of OGO-6 neutral mass spectrometer measurements near 450 km are discussed qualitatively as well as quantitatively on the basis of a theoretical model. Observations and conclusion are summarized: (1) During equinox the temperature maximum occurs after 1600 LT at the equator and shifts toward 1500 LT at the poles, while the oxygen concentration at 450 km peaks about one hour earlier. (2) There is general agreement between the magnitudes and phases of the diurnal, semidiurnal and terdiuranal temperature components at 450 km from theory as well as OGO-6 and radar backscatter measurements. (3) The maximum in the diurnal variation of He is observed near 1030 LT consistent with theoretical results which further emphasize the importance of dynamics and diffusion. (4) During solstice conditions the diurnal temperature maximum shifts toward later local times, in substantial agreement with radar temperature measurements. (5) the temperature-oxygen density phase difference at 450 km is observed to decrease with latitude from the winter toward the summer hemisphere, where oxygen may even peak after the temperature at high latitudes.

  3. Variations in global temperature and precipitation for the period of 1948 to 2010.

    PubMed

    Sun, Qiaohong; Kong, Dongxian; Miao, Chiyuan; Duan, Qingyun; Yang, Tiantian; Ye, Aizhong; Di, Zhenhua; Gong, Wei

    2014-09-01

    Climate change has impacts on both natural and human systems. Accurate information regarding variations in precipitation and temperature is essential for identifying and understanding these potential impacts. This research applied Mann-Kendall, rescaled range analysis and wave transform methods to analyze the trends and periodic properties of global and regional surface air temperature (SAT) and precipitation (PR) over the period of 1948 to 2010. The results show that 65.34% of the area studied exhibits significant warming trends (p < 0.05) while only 3.18% of the area exhibits significant cooling trends. The greatest warming trends are observed in Antarctica (0.32 °C per decade) and Middle Africa (0.21 °C per decade). Notably, 62.26% of the area became wetter, while 22.01% of the area shows drying trends. Northern Europe shows the largest precipitation increase, 12.49 mm per decade. Western Africa shows the fastest drying, -21.05 mm per decade. The rescaled range analysis reveals large areas that show persistent warming trends; this behavior in SAT is more obvious than that in PR. Wave transform results show that a 1-year period of SAT variation dominates in all regions, while inconsistent 0.5-year bands are observed in East Asia, Middle Africa, and Southeast Asia. In PR, significant power in the wavelet power spectrum at a 1-year period was observed in 17 regions, i.e., in all regions studied except Western Europe, where precipitation is instead characterized by 0.5-year and 0.25-year periods. Overall, the variations in SAT and PR can be consistent with the combined impacts of natural and anthropogenic factors, such as atmospheric concentrations of greenhouse gases, the internal variability of climate system, and volcanic eruptions.

  4. Toward Spectroscopically Detecting the Global Latitudinal Temperature Variation on the Solar Surface

    NASA Astrophysics Data System (ADS)

    Takeda, Y.; UeNo, S.

    2017-09-01

    A very slight rotation-induced latitudinal temperature variation (presumably on the order of several kelvin) on the solar surface is theoretically expected. While recent high-precision solar brightness observations reported its detection, confirmation by an alternative approach using the strengths of spectral lines is desirable, for which reducing the noise due to random fluctuation caused by atmospheric inhomogeneity is critical. Toward this difficult task, we carried out a pilot study of spectroscopically investigating the relative variation of temperature (T) at a number of points in the solar circumference region near to the limb (where latitude dependence should be detectable, if any exists) based on the equivalent widths (W) of 28 selected lines in the 5367 - 5393 Å and 6075 - 6100 Å regions. We paid special attention to i) clarifying which types of lines should be employed and ii) how much precision is attainable in practice. We found that lines with strong T-sensitivity (|log W/log T|) should be used and that very weak lines should be avoided because they inevitably suffer strong relative fluctuations (Δ W/W). Our analysis revealed that a precision of Δ T/T ≈ 0.003 (corresponding to ≈ 15 K) can be achieved at best by a spectral line with comparatively large |log W/log T|, although this can possibly be further improved When a number of lines are used all together. Accordingly, if many such favorable lines could be measured with subpercent precision of Δ W/W and by averaging the resulting Δ T/T from each line, the random noise would eventually be reduced to ≲ 1 K and detection of a very subtle amount of global T-gradient might be possible.

  5. Reconstructing Variations of Global Sea-Surface Temperature during the Last Interglaciation

    NASA Astrophysics Data System (ADS)

    Hoffman, J. S.; Clark, P. U.; He, F.; Parnell, A. C.

    2015-12-01

    The last interglaciation (LIG; ~130-116 ka) was the most recent period in Earth history with higher-than-present global sea level (≥6 m) under similar-to-preindustrial concentrations of atmospheric CO2, suggesting additional feedbacks related to albedo, insolation, and ocean circulation in generating the apparent climatic differences between the LIG and present Holocene. However, our understanding of how much warmer the LIG sea surface was relative to the present interglaciation remains uncertain, with current estimates suggesting from 0°C to 2°C warmer than late-20thcentury average global temperatures. Moreover, the timing, spatial expression, and amplitude of regional and global sea surface temperature variability related to other climate forcing during the LIG are poorly constrained, largely due to uncertainties in age control and proxy temperature reconstructions. An accurate characterization of global and regional temperature change during the LIG can serve as a benchmark for paleoclimate modeling intercomparison projects and help improve understanding of sea-level sensitivity to temperature change. We will present a global compilation (~100 published records) of sea surface temperature (SST) and other climate reconstructions spanning the LIG. Using a Monte Carlo-enabled cross-correlation maximization algorithm to climatostratigraphically align proxy records and then account for both the resulting chronologic and proxy calibration uncertainties with Bayesian statistical inference, our results quantify the spatial timing, amplitude, and uncertainty in estimates of global and regional sea surface temperature change during the LIG and its relation to potential forcings.

  6. Global variation in the effects of ambient temperature on mortality: a systematic evaluation

    PubMed Central

    Guo, Yuming; Gasparrini, Antonio; Armstrong, Ben; Li, Shanshan; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; de Sousa Zanotti Stagliorio Coelho, Micheline; Leone, Michela; Pan, Xiaochuan; Tong, Shilu; Tian, Linwei; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue-Liang Leon; Wu, Chang-Fu; Punnasiri, Kornwipa; Yi, Seung-Muk; Michelozzi, Paola; Saldiva, Paulo Hilario Nascimento; Williams, Gail

    2014-01-01

    Background Studies have examined the effects of temperature on mortality in a single city, country or region. However, less evidence is available on the variation in the associations between temperature and mortality in multiple countries, analyzed simultaneously. Methods We obtained daily data on temperature and mortality in 306 communities from 12 countries/regions (Australia, Brazil, Thailand, China, Taiwan, Korea, Japan, Italy, Spain, United Kingdom, United States and Canada). Two-stage analyses were used to assess the non-linear and delayed relationship between temperature and mortality. In the first stage, a Poisson regression allowing over-dispersion with distributed lag non-linear model was used to estimate the community-specific temperature-mortality relationship. In the second stage, a multivariate meta-analysis was used to pool the non-linear and delayed effects of ambient temperature at the national level, in each country. Results The temperatures associated with the lowest mortality were around the 75th percentile of temperature in all the countries/regions, ranging from 66th (Taiwan) to 80th (UK) percentiles. The estimated effects of cold and hot temperatures on mortality varied by community and country. Meta-analysis results show that both cold and hot temperatures increased the risk of mortality in all the countries/regions. Cold effects were delayed and lasted for many days, while hot effects appeared quickly and did not last long. Conclusions People have some ability to adapt to their local climate type, but both cold and hot temperatures are still associated with the risk of mortality. Public health strategies to alleviate the impact of ambient temperatures are important, in particular in the context of climate change. PMID:25166878

  7. Dynamical evidence for causality between galactic cosmic rays and interannual variation in global temperature

    SciTech Connect

    Tsonis, Anastasios A.; Deyle, Ethan R.; May, Robert M.; Sugihara, George; Swanson, Kyle; Verbeten, Joshua D.; Wang, Geli

    2015-03-02

    As early as 1959, it was hypothesized that an indirect link between solar activity and climate could be mediated by mechanisms controlling the flux of galactic cosmic rays (CR). Although the connection between CR and climate remains controversial, a significant body of laboratory evidence has emerged at the European Organization for Nuclear Research and elsewhere, demonstrating the theoretical mechanism of this link. In this article, we present an analysis based on convergent cross mapping, which uses observational time series data to directly examine the causal link between CR and year-to-year changes in global temperature. Despite a gross correlation, we find no measurable evidence of a causal effect linking CR to the overall 20th-century warming trend. Furthermore, on short interannual timescales, we find a significant, although modest, causal effect between CR and short-term, year-to-year variability in global temperature that is consistent with the presence of nonlinearities internal to the system. Thus, although CR do not contribute measurably to the 20th-century global warming trend, they do appear as a nontraditional forcing in the climate system on short interannual timescales.

  8. Dynamical evidence for causality between galactic cosmic rays and interannual variation in global temperature

    DOE PAGES

    Tsonis, Anastasios A.; Deyle, Ethan R.; May, Robert M.; ...

    2015-03-02

    As early as 1959, it was hypothesized that an indirect link between solar activity and climate could be mediated by mechanisms controlling the flux of galactic cosmic rays (CR). Although the connection between CR and climate remains controversial, a significant body of laboratory evidence has emerged at the European Organization for Nuclear Research and elsewhere, demonstrating the theoretical mechanism of this link. In this article, we present an analysis based on convergent cross mapping, which uses observational time series data to directly examine the causal link between CR and year-to-year changes in global temperature. Despite a gross correlation, we findmore » no measurable evidence of a causal effect linking CR to the overall 20th-century warming trend. Furthermore, on short interannual timescales, we find a significant, although modest, causal effect between CR and short-term, year-to-year variability in global temperature that is consistent with the presence of nonlinearities internal to the system. Thus, although CR do not contribute measurably to the 20th-century global warming trend, they do appear as a nontraditional forcing in the climate system on short interannual timescales.« less

  9. Horizontal Temperature Variability in the Stratosphere: Global Variations Inferred from CRISTA Data

    NASA Technical Reports Server (NTRS)

    Eidmann, G.; Offermann, D.; Jarisch, M.; Preusse, P.; Eckermann, S. D.; Schmidlin, F. J.

    2001-01-01

    In two separate orbital campaigns (November, 1994 and August, 1997), the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) instrument acquired global stratospheric data of high accuracy and high spatial resolution. The standard limb-scanned CRISTA measurements resolved atmospheric spatial structures with vertical dimensions greater than or equal to 1.5 - 2 km and horizontal dimensions is greater than or equal to 100 - 200 km. A fluctuation analysis of horizontal temperature distributions derived from these data is presented. This method is somewhat complementary to conventional power-spectral analysis techniques.

  10. Venus mesosphere and thermosphere. II - Global circulation, temperature, and density variations

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Dickinson, R. E.; Ridley, E. C.; Roble, R. G.; Nagy, A. F.

    1986-01-01

    The Dickinson and Ridley (1977) symmetric, two-dimensional hydrodynamical model framework is presently used as the basis of a reexamination of the circulation and structure of the Venus thermosphere recently revealed by Pioneer Venus observations. The observed day-to-night variation of composition and temperatures can largely be derived by a wave-drag parameterization yielding a weaker circulation system than that predicted prior to Pioneer Venus. It is also suggested that eddy diffusion is a minor contributor to the maintenance of observed day and nightside densities, and that eddy coefficients are smaller than than those of one-dimensional composition models previously employed.

  11. Venus mesosphere and thermosphere. II - Global circulation, temperature, and density variations

    NASA Technical Reports Server (NTRS)

    Bougher, S. W.; Dickinson, R. E.; Ridley, E. C.; Roble, R. G.; Nagy, A. F.

    1986-01-01

    The Dickinson and Ridley (1977) symmetric, two-dimensional hydrodynamical model framework is presently used as the basis of a reexamination of the circulation and structure of the Venus thermosphere recently revealed by Pioneer Venus observations. The observed day-to-night variation of composition and temperatures can largely be derived by a wave-drag parameterization yielding a weaker circulation system than that predicted prior to Pioneer Venus. It is also suggested that eddy diffusion is a minor contributor to the maintenance of observed day and nightside densities, and that eddy coefficients are smaller than than those of one-dimensional composition models previously employed.

  12. Dynamical evidence for causality between galactic cosmic rays and interannual variation in global temperature.

    PubMed

    Tsonis, Anastasios A; Deyle, Ethan R; May, Robert M; Sugihara, George; Swanson, Kyle; Verbeten, Joshua D; Wang, Geli

    2015-03-17

    As early as 1959, it was hypothesized that an indirect link between solar activity and climate could be mediated by mechanisms controlling the flux of galactic cosmic rays (CR) [Ney ER (1959) Nature 183:451-452]. Although the connection between CR and climate remains controversial, a significant body of laboratory evidence has emerged at the European Organization for Nuclear Research [Duplissy J, et al. (2010) Atmos Chem Phys 10:1635-1647; Kirkby J, et al. (2011) Nature 476(7361):429-433] and elsewhere [Svensmark H, Pedersen JOP, Marsh ND, Enghoff MB, Uggerhøj UI (2007) Proc R Soc A 463:385-396; Enghoff MB, Pedersen JOP, Uggerhoj UI, Paling SM, Svensmark H (2011) Geophys Res Lett 38:L09805], demonstrating the theoretical mechanism of this link. In this article, we present an analysis based on convergent cross mapping, which uses observational time series data to directly examine the causal link between CR and year-to-year changes in global temperature. Despite a gross correlation, we find no measurable evidence of a causal effect linking CR to the overall 20th-century warming trend. However, on short interannual timescales, we find a significant, although modest, causal effect between CR and short-term, year-to-year variability in global temperature that is consistent with the presence of nonlinearities internal to the system. Thus, although CR do not contribute measurably to the 20th-century global warming trend, they do appear as a nontraditional forcing in the climate system on short interannual timescales.

  13. Global and seasonal variations in three-dimensional gravity wave momentum flux from satellite limb-sounding temperatures

    NASA Astrophysics Data System (ADS)

    Alexander, M. Joan

    2015-08-01

    Satellite limb-sounding methods provide the best global temperature data available for simultaneous measurement of gravity wave horizontal and vertical structures needed to estimate momentum flux and constrain wave effects on general circulation. Gravity waves vary in the three spatial dimensions and time, so the ideal measurement observes all three dimensions at high resolution nearly simultaneously. High Resolution Dynamics Limb Sounder (HIRDLS) measurements give near-simultaneous profiles in close proximity and at high vertical resolution, but these coincident profiles lie only along the plane of the measurement track. Here we combine HIRDLS and radio occultation data sets to obtain three-dimensional properties of gravity waves on a global scale as well as seasonal variations. The results show dramatic changes from previous estimates using either data set alone. Changes include much larger momentum fluxes and latitudinal variations in propagation direction that support an enhanced role for gravity wave forcing of middle atmosphere circulation.

  14. Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia

    PubMed Central

    Mann, Michael E.; Zhang, Zhihua; Hughes, Malcolm K.; Bradley, Raymond S.; Miller, Sonya K.; Rutherford, Scott; Ni, Fenbiao

    2008-01-01

    Following the suggestions of a recent National Research Council report [NRC (National Research Council) (2006) Surface Temperature Reconstructions for the Last 2,000 Years (Natl Acad Press, Washington, DC).], we reconstruct surface temperature at hemispheric and global scale for much of the last 2,000 years using a greatly expanded set of proxy data for decadal-to-centennial climate changes, recently updated instrumental data, and complementary methods that have been thoroughly tested and validated with model simulation experiments. Our results extend previous conclusions that recent Northern Hemisphere surface temperature increases are likely anomalous in a long-term context. Recent warmth appears anomalous for at least the past 1,300 years whether or not tree-ring data are used. If tree-ring data are used, the conclusion can be extended to at least the past 1,700 years, but with additional strong caveats. The reconstructed amplitude of change over past centuries is greater than hitherto reported, with somewhat greater Medieval warmth in the Northern Hemisphere, albeit still not reaching recent levels. PMID:18765811

  15. Global and Regional Variations in Mean Temperature and Warm Extremes in Large-Member Historical AGCM Simulation

    NASA Astrophysics Data System (ADS)

    Kamae, Y.; Shiogama, H.; Imada, Y.; Mori, M.; Arakawa, O.; Mizuta, R.; Yoshida, K.; Ishii, M.; Watanabe, M.; Kimoto, M.; Ueda, H.

    2015-12-01

    Frequency of heat extremes during the summer season has increased continuously since the late 20th century despite the global warming hiatus. In previous studies, anthropogenic influences, natural variation in sea surface temperature (SST), and internal atmospheric variabilities are suggested to be factors contributing to the increase in the frequency of warm extremes. Here 100-member ensemble historical simulations were performed (called "database for Probabilistic Description of Future climate"; d4PDF) to examine physical mechanisms responsible for the increasing hot summers and attribute to the anthropogenic influences or natural climate variability. 60km resolution MRI-AGCM ensemble simulations can reproduce historical variations in the mean temperature and warm extremes. Natural SST variability in the Pacific and Atlantic Oceans contribute to the decadal variation in the frequency of hot summers in the Northern Hemisphere middle latitude. For example, the surface temperature over western North America, including California, is largely influenced by anomalous atmospheric circulation pattern associated with Pacific SST variability. Future projections based on anomalous SST patterns derived from coupled climate model simulations will also be introduced.

  16. A New Global Empirical Model of the Electron Temperature with the Inclusion of the Solar Activity Variations for IRI

    NASA Technical Reports Server (NTRS)

    Truhlik, V.; Triskova, L.

    2012-01-01

    A data-base of electron temperature (T(sub e)) comprising of most of the available LEO satellite measurements in the altitude range from 350 to 2000 km has been used for the development of a new global empirical model of T(sub e) for the International Reference Ionosphere (IRI). For the first time this will include variations with solar activity. Variations at five fixed altitude ranges centered at 350, 550, 850, 1400, and 2000 km and three seasons (summer, winter, and equinox) were represented by a system of associated Legendre polynomials (up to the 8th order) in terms of magnetic local time and the earlier introduced in vdip latitude. The solar activity variations of T(sub e) are represented by a correction term of the T(sub e) global pattern and it has been derived from the empirical latitudinal profiles of T(sub e) for day and night (Truhlik et al., 2009a). Comparisons of the new T(sub e) model with data and with the IRI 2007 Te model show that the new model agrees well with the data generally within standard deviation limits and that the model performs better than the current IRI T(sub e) model.

  17. A New Global Empirical Model of the Electron Temperature with the Inclusion of the Solar Activity Variations for IRI

    NASA Technical Reports Server (NTRS)

    Truhlik, V.; Triskova, L.

    2012-01-01

    A data-base of electron temperature (T(sub e)) comprising of most of the available LEO satellite measurements in the altitude range from 350 to 2000 km has been used for the development of a new global empirical model of T(sub e) for the International Reference Ionosphere (IRI). For the first time this will include variations with solar activity. Variations at five fixed altitude ranges centered at 350, 550, 850, 1400, and 2000 km and three seasons (summer, winter, and equinox) were represented by a system of associated Legendre polynomials (up to the 8th order) in terms of magnetic local time and the earlier introduced in vdip latitude. The solar activity variations of T(sub e) are represented by a correction term of the T(sub e) global pattern and it has been derived from the empirical latitudinal profiles of T(sub e) for day and night (Truhlik et al., 2009a). Comparisons of the new T(sub e) model with data and with the IRI 2007 Te model show that the new model agrees well with the data generally within standard deviation limits and that the model performs better than the current IRI T(sub e) model.

  18. Interannual Variations in Arctic Winter Temperature: The Role of Global Scale Teleconnections

    DTIC Science & Technology

    2015-06-01

    Research Laboratory FMA February-April GCC Global Climate Change GPH geopotential height hPa hectoPascal IR infrared radiative JAS July-September...highlights that the changes observed in Arctic climate can rapidly affect multiple interconnected areas within the Arctic and around the globe (NRC 2014...These cause and effect relationships are also known as a teleconnections. When trying to understand or predict changes in Arctic climate (or

  19. Statistical examination of climatological data relevant to global temperature variation. Final report

    SciTech Connect

    Gray, H.L.; Gunst, R.F.; Woodward, W.A.

    1994-07-01

    Since the writing of the original proposal, debate within the scientific community continues concerning the existence of a global warming trend due to the build-up of CO{sub 2} and other greenhouse gases. Thus sound statistical analysis of the pertinent data continues to be a critical need. As indicated in the original proposal, the goals of this project are to critically examine the quality of existing data sets upon which conclusions are being drawn as well as to use state-of-the-art statistical techniques to model appropriate data for purposes of assessing whether a warming trend exists and identifying and understanding the explanatory variables. In this report the progress which has been made is discussed.

  20. Global sea level linked to global temperature

    PubMed Central

    Vermeer, Martin; Rahmstorf, Stefan

    2009-01-01

    We propose a simple relationship linking global sea-level variations on time scales of decades to centuries to global mean temperature. This relationship is tested on synthetic data from a global climate model for the past millennium and the next century. When applied to observed data of sea level and temperature for 1880–2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance. For future global temperature scenarios of the Intergovernmental Panel on Climate Change's Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. PMID:19995972

  1. Global Surface Temperature Change

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Ruedy, R.; Sato, M.; Lo, K.

    2010-12-01

    We update the Goddard Institute for Space Studies (GISS) analysis of global surface temperature change, compare alternative analyses, and address questions about perception and reality of global warming. Satellite-observed night lights are used to identify measurement stations located in extreme darkness and adjust temperature trends of urban and periurban stations for nonclimatic factors, verifying that urban effects on analyzed global change are small. Because the GISS analysis combines available sea surface temperature records with meteorological station measurements, we test alternative choices for the ocean data, showing that global temperature change is sensitive to estimated temperature change in polar regions where observations are limited. We use simple 12 month (and n × 12) running means to improve the information content in our temperature graphs. Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior 2 decades, despite year-to-year fluctuations associated with the El Niño-La Niña cycle of tropical ocean temperature. Record high global 12 month running mean temperature for the period with instrumental data was reached in 2010.

  2. Global model of longitude/UT variations in thermospheric composition and temperature based on mass spectrometer data

    NASA Technical Reports Server (NTRS)

    Hedin, A. E.; Reber, C. A.; Spencer, N. W.; Brinton, H. C.; Kayser, D. C.

    1979-01-01

    Measurements of N2, O, He, and Ar densities from neutral gas mass spectrometers on four satellites and inferred O2 and H densities from an ion mass spectrometer have been combined to produce a model of longitude/UT variations in thermospheric neutral composition and temperature. The longitude/UT model is an extension of the mass spectrometer-incoherent scatter thermospheric model (Hedin et al., 1977) and uses spherical harmonic terms dependent on geographic latitude, longitude, and UT. The combined longitude and UT variations reflect the influence of the geomagnetic field but indicate that the variations may not simply be represented in magnetic coordinates.

  3. Variation among genotypes in responses to increasing temperature in a marine parasite: evolutionary potential in the face of global warming?

    PubMed

    Berkhout, Boris W; Lloyd, Melanie M; Poulin, Robert; Studer, Anja

    2014-11-01

    Climates are changing worldwide, and populations are under selection to adapt to these changes. Changing temperature, in particular, can directly impact ectotherms and their parasites, with potential consequences for whole ecosystems. The potential of parasite populations to adapt to climate change largely depends on the amount of genetic variation they possess in their responses to environmental fluctuations. This study is, to our knowledge, the first to look at differences among parasite genotypes in response to temperature, with the goal of quantifying the extent of variation among conspecifics in their responses to increasing temperature. Snails infected with single genotypes of the trematode Maritrema novaezealandensis were sequentially acclimatised to two different temperatures, 'current' (15°C) and 'elevated' (20°C), over long periods. These temperatures are based on current average field conditions in the natural habitat and those predicted to occur during the next few decades. The output and activity of cercariae (free-swimming infective stages emerging from snails) were assessed for each genotype at each temperature. The results indicate that, on average, both cercarial output and activity are higher at the elevated acclimation temperature. More importantly, the output and activity of cercariae are strongly influenced by a genotype-by-temperature interaction, such that different genotypes show different responses to increasing temperature. Both the magnitude and direction (increase or decrease) of responses to temperature varied widely among genotypes. Therefore, there is much potential for natural selection to act on this variation, and predicting how the trematode M. novaezealandensis will respond to the climate changes predicted for the next century will prove challenging.

  4. Reconciliation of global temperatures

    NASA Astrophysics Data System (ADS)

    Benestad, R. E.

    2012-03-01

    /warming (Isaksen et al 2007), all point to unusual warm conditions in the Arctic. Foster and Rahmstorf examine global mean temperature trends after accounting for variations associated with three different naturally occurring phenomena: El Niño-Southern Oscillation, volcanic aerosols and solar variability. They used a similar approach to Lean and Rind (2008), but unlike Solomon et al (2010), they did not account for stratospheric water vapour concentrations. Their findings agree with Kaufmann et al (2011) who argue that this factor plays a minor role. Foster and Rahmstorf did not need to account for anthropogenic sulfur aerosols, as a fairly linear warming trend became discernable once the ENSO, solar activity and volcanism were accounted for. There is always a risk that multiple regression analysis may misattribute significance to unrelated factors (Benestad and Schmidt 2009), and Foster and Rahmstorf made some efforts to test whether their results could be affected by such spurious effects, making their results more convincing. Unfortunately, this is not always the case for papers in the scientific literature, and sometimes papers appear in journals even if they cannot be justified on scientific grounds (i.e. Wagner 2011). An interesting aside, however, is that similar physical principles implying a warming resulting from higher CO2 concentrations also are the basis for estimating the temperature from the microwave channels measured by satellite-borne instruments. The fact that Foster and Rahmstorf reconcile the trends seen in the in situ surface and satellite-borne remote sensing data brings out the consistency with the physics believed to be central to global warming. In my view, Foster and Rahmstorf do not come up with new ground-breaking results, but rather a view that fits in with the tacit knowledge about climate. The most interesting aspect is perhaps the different implications for effects associated with stratospheric water vapour and sulfur aerosols. It is also

  5. Global temperature monitoring from space

    NASA Technical Reports Server (NTRS)

    Spencer, R. W.

    1994-01-01

    Global and regional temperature variations in the lower troposphere and lower stratosphere are examined for the period 1979-92 from Microwave Sounder Unit (MSU) data obtained by the Television Infrared Observation Satellite (TIROS)-N series of National Oceanic and Atmospheric Administration (NOAA) operational satellites. In the lower troposphere, globally-averaged temperature variations appear to be dominated by tropical El Nino (warm) and La Nina (cool) events and volcanic eruptions. The Pinatubo volcanic eruption in June 1991 appears to have initiated a cooling trend which persisted through the most recent data analyzed (July, 1992), and largely overwhelmed the warming from the 1991-92 El Nino. The cooling has been stronger in the Northern Hemisphere than in the Southern Hemisphere. The temperature trend over the 13.5 year satellite record is small (+0.03 C) compared to the year-to-year variability (0.2-0.4 C), making detection of any global warming signal fruitless to date. However, the future global warming trend, currently predicted to be around 0.3 C/decade, will be much easier to discern should it develop. The lower stratospheric temperature record is dominated by warm episodes from the Pinatubo eruption and the March 1982 eruption of El Chichon volcano.

  6. Global temperature monitoring from space

    NASA Technical Reports Server (NTRS)

    Spencer, R. W.

    1994-01-01

    Global and regional temperature variations in the lower troposphere and lower stratosphere are examined for the period 1979-92 from Microwave Sounder Unit (MSU) data obtained by the Television Infrared Observation Satellite (TIROS)-N series of National Oceanic and Atmospheric Administration (NOAA) operational satellites. In the lower troposphere, globally-averaged temperature variations appear to be dominated by tropical El Nino (warm) and La Nina (cool) events and volcanic eruptions. The Pinatubo volcanic eruption in June 1991 appears to have initiated a cooling trend which persisted through the most recent data analyzed (July, 1992), and largely overwhelmed the warming from the 1991-92 El Nino. The cooling has been stronger in the Northern Hemisphere than in the Southern Hemisphere. The temperature trend over the 13.5 year satellite record is small (+0.03 C) compared to the year-to-year variability (0.2-0.4 C), making detection of any global warming signal fruitless to date. However, the future global warming trend, currently predicted to be around 0.3 C/decade, will be much easier to discern should it develop. The lower stratospheric temperature record is dominated by warm episodes from the Pinatubo eruption and the March 1982 eruption of El Chichon volcano.

  7. Global temperature change.

    PubMed

    Hansen, James; Sato, Makiko; Ruedy, Reto; Lo, Ken; Lea, David W; Medina-Elizade, Martin

    2006-09-26

    Global surface temperature has increased approximately 0.2 degrees C per decade in the past 30 years, similar to the warming rate predicted in the 1980s in initial global climate model simulations with transient greenhouse gas changes. Warming is larger in the Western Equatorial Pacific than in the Eastern Equatorial Pacific over the past century, and we suggest that the increased West-East temperature gradient may have increased the likelihood of strong El Niños, such as those of 1983 and 1998. Comparison of measured sea surface temperatures in the Western Pacific with paleoclimate data suggests that this critical ocean region, and probably the planet as a whole, is approximately as warm now as at the Holocene maximum and within approximately 1 degrees C of the maximum temperature of the past million years. We conclude that global warming of more than approximately 1 degrees C, relative to 2000, will constitute "dangerous" climate change as judged from likely effects on sea level and extermination of species.

  8. Global temperature change

    PubMed Central

    Hansen, James; Sato, Makiko; Ruedy, Reto; Lo, Ken; Lea, David W.; Medina-Elizade, Martin

    2006-01-01

    Global surface temperature has increased ≈0.2°C per decade in the past 30 years, similar to the warming rate predicted in the 1980s in initial global climate model simulations with transient greenhouse gas changes. Warming is larger in the Western Equatorial Pacific than in the Eastern Equatorial Pacific over the past century, and we suggest that the increased West–East temperature gradient may have increased the likelihood of strong El Niños, such as those of 1983 and 1998. Comparison of measured sea surface temperatures in the Western Pacific with paleoclimate data suggests that this critical ocean region, and probably the planet as a whole, is approximately as warm now as at the Holocene maximum and within ≈1°C of the maximum temperature of the past million years. We conclude that global warming of more than ≈1°C, relative to 2000, will constitute “dangerous” climate change as judged from likely effects on sea level and extermination of species. PMID:17001018

  9. Precipitation drives global variation in natural selection.

    PubMed

    Siepielski, Adam M; Morrissey, Michael B; Buoro, Mathieu; Carlson, Stephanie M; Caruso, Christina M; Clegg, Sonya M; Coulson, Tim; DiBattista, Joseph; Gotanda, Kiyoko M; Francis, Clinton D; Hereford, Joe; Kingsolver, Joel G; Augustine, Kate E; Kruuk, Loeske E B; Martin, Ryan A; Sheldon, Ben C; Sletvold, Nina; Svensson, Erik I; Wade, Michael J; MacColl, Andrew D C

    2017-03-03

    Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation-natural selection-are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale.

  10. Correlation between the variation in observed melting temperatures and structural motifs of the global minima of gallium clusters: an ab initio study.

    PubMed

    Susan, Anju; Kibey, Aniruddha; Kaware, Vaibhav; Joshi, Kavita

    2013-01-07

    We have investigated the correlation between the variation in the melting temperature and the growth pattern of small positively charged gallium clusters. Significant shift in the melting temperatures was observed for a change of only few atoms in the size of the cluster. Clusters with size between 31-42 atoms melt between 500-600 K whereas those with 46-48 atoms melt around 800 K. Density functional theory based first principles simulations have been carried out on Ga(n)(+) clusters with n = 31, ..., 48. At least 150 geometry optimizations have been performed towards the search for the global minima for each size resulting in about 3000 geometry optimizations. For gallium clusters in this size range, the emergence of spherical structures as the ground state leads to higher melting temperature. The well-separated core and surface shells in these clusters delay isomerization, which results in the enhanced stability of these clusters at elevated temperatures. The observed variation in the melting temperature of these clusters therefore has a structural origin.

  11. Correlation between the variation in observed melting temperatures and structural motifs of the global minima of gallium clusters: An ab initio study

    NASA Astrophysics Data System (ADS)

    Susan, Anju; Kibey, Aniruddha; Kaware, Vaibhav; Joshi, Kavita

    2013-01-01

    We have investigated the correlation between the variation in the melting temperature and the growth pattern of small positively charged gallium clusters. Significant shift in the melting temperatures was observed for a change of only few atoms in the size of the cluster. Clusters with size between 31-42 atoms melt between 500-600 K whereas those with 46-48 atoms melt around 800 K. Density functional theory based first principles simulations have been carried out on Ga+n clusters with n = 31, …, 48. At least 150 geometry optimizations have been performed towards the search for the global minima for each size resulting in about 3000 geometry optimizations. For gallium clusters in this size range, the emergence of spherical structures as the ground state leads to higher melting temperature. The well-separated core and surface shells in these clusters delay isomerization, which results in the enhanced stability of these clusters at elevated temperatures. The observed variation in the melting temperature of these clusters therefore has a structural origin.

  12. Global Stress Variation over Time

    NASA Astrophysics Data System (ADS)

    Yi, H.; Lu, Z.; Wen, L.

    2015-12-01

    Understanding how stress changes over time is important as it is related to studies of earthquake triggering and mantle rheology. We calculate stress variation at the Earth's surface on the global scale from 2003 to 2014, resultant from several major physical forces acting on the Earth. The physical forces we considered include the surface loading due to terrestrial water storage (TWS), force associated with post-glacial rebound (PGR) and tidal loading (including solid tide and ocean tide). The stress change associated with TWS is calculated in this way: we infer TWS from monthly gravity field of the Gravity Recovery and Climate Experiment (GRACE), in which gravity variation associated with PGR has been removed; we then estimate stress change at the Earth's surface as the elastic response of the GRACE-inferred TWS change. The stress change associated with PGR is calculated as the rate of viscoelastic stress change responding to ice loading from ICE-5G model. And, tidal stress is calculated as the elastic response of the Earth to the traction forces of the Sun and the Moon (solid tide) and to the loading of ocean tide. The total stress change is the sum of the stress changes associated with these three types of forces. As first result, in the study period from 2003 to 2014, the radial normal stress variation exhibits a prominent decreasing trend in southern Africa and Queen Maud Land of Antarctica, an increasing trend in Alaska of the US (United States), Greenland and Marie Byrd Land of Antarctica, and strong annual cycles in southern Africa and Alaska of the US. We will present the geographical distribution of global stress variation from 2003 to 2014 and discuss its possible implications.

  13. The influence of composition and final pyrolysis temperature variations on global kinetics of combustion of segregated municipal solid waste

    NASA Astrophysics Data System (ADS)

    Pranoto; Himawanto, D. A.; Arifin, N. A.

    2017-04-01

    The combustion of segregated municipal solid waste (MSW) and the resulted char from the pyrolysis process were investigated in this research. The segregated MSW that was collected and used can be divided into organic and inorganic waste materials. The organic materials were bamboo and banana leaves and the inorganic materials were Styrofoam and snack wrappings. The composition ratio of the waste was based on the percentage of weight of each sample. The thermal behaviour of the segregated MSW was investigated by thermo gravimetric analysis. For the pyrolysis process the prepared samples of 200gram were heated from ambient temperature until a variance of final pyrolysis temperature of 550°C, 650°C and 750°C at a constant heating rate of 25°C/min. It was found that the highest activation energy of the raw materials is achieved from sample CC1 (Char with 100% inorganic materials). The activation energy of the raw materials is relatively lower than that of the char. The higher the final pyrolysis temperature, the lower the calorific value of char. The calorific value gradually increases with the amount of inorganic materials.

  14. ACS PSF Variations with Temperatures

    NASA Astrophysics Data System (ADS)

    Sahu, Kailash C.; Lallo, Matt; Makidon, Russ

    2007-09-01

    We have used the HST ACS/WFC observations of a Galactic bulge field taken over a continuous interval of 7 days (Prop 9750) to investigate the possible dependence of the ACS focus with the external temperatures. This dataset allows us to investigate possible focus variations over timescales of a few hours to a few days. The engineering data related to the external temperatures for this duration show that the maximum temperature change occurred over the first 1.5 days. Among all the different temperatures recorded, the truss diametric differential and the truss axial temperatures are the only two temperatures which have the same timescale of variation as the PSFwidth variations. The PSF-widths also strongly correlate with these two temperatures during this time interval. We empirically fit the PSF-width variations with these 2 temperature sensor values. This suggests that the focus has a similar dependence, and we recommend that this finding be followed up with the determination of actual focus values to check if the focus values indeed have the same correlation. If so, the temperature data can be useful in estimating the focus values, which can then be used to predict the PSFs to a first order.

  15. Variation in electromagnetic parameters of the solar magnetic cycle as cause of the 22-year oscillation in global temperature and rotation rate of the Earth

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Tamara; Laptukhov, Alexej

    Solar radiation is not the only heat source of the upper atmosphere. Solar energy is captured by magnetosphere and atmosphere via electromagnetic interaction of the solar wind with terrestrial field. Aim of the paper is to explain correlated 22-year variations of sunspot numbers W, global temperature Tgl and angular velocity w of the Earth derived by us on basis of observational data. First of all we analyze data of the interplanetary magnetic field (IMF) and the solar wind velocity measured at the Earth's orbit for the period of 1964-2005. Based on the data we show that heliomagnetic moment during 11-year solar activity cycle changes its direction, rotating from north pole through equators to south pole, and back. Manifestation of this magnetic solar cycle is annual variation of the electromagnetic parameters. The annual variations of values of electric field E, vector of Poyting P, IMF were obtained for different phases of the 22-yr solar cycle. We show that all the parameters are higher for odd 11-yr cycles than ones for even 11-yr cycles (11-yr cycle is determined between maxima of W). Moreover, the contrast between two cycles displays strength in summer months, when heat machine in atmosphere raised by the temperature difference between sunlit north polar cap and dark south polar cap works actively. The difference of the parameters of W1 and W2 cycles leads in the end to difference of their influence to polar magnetosphere and ionosphere. Processes in magnetosphere controlled by the solar wind causes two main phenomena in the upper polar atmosphere: particle precipitation and convection of ionospheric plasma caused by E. The particle precipitation influences on conductivities and currents. As result the Poyting flux P=[ExB] coming to polar cap leads to heating of polar ionosphere and atmosphere, temperature contrast between two caps, intensification of the inter-hemisphere heat machine in the upper atmosphere, change of angular moment of atmospheric zonal

  16. Global surface temperatures and the atmospheric electrical circuit

    NASA Technical Reports Server (NTRS)

    Price, Colin

    1993-01-01

    To monitor future global temperature trends, it would be extremely useful if parameters nonlinearly related to surface temperature could be found, thereby amplifying any warming signal that may exist. Evidence that global thunderstorm activity is nonlinearly related to diurnal, seasonal and interannual temperature variations is presented. Since global thunderstorm activity is also well correlated with the earth's ionospheric potential, it appears that variations of ionospheric potential, that can be measured at a single location, may be able to supply valuable information regarding global surface temperature fluctuations. The observations presented enable a prediction that a 1 percent increase in global surface temperatures may result in a 20 percent increase in ionospheric potential.

  17. Global surface temperatures and the atmospheric electrical circuit

    NASA Technical Reports Server (NTRS)

    Price, Colin

    1993-01-01

    To monitor future global temperature trends, it would be extremely useful if parameters nonlinearly related to surface temperature could be found, thereby amplifying any warming signal that may exist. Evidence that global thunderstorm activity is nonlinearly related to diurnal, seasonal and interannual temperature variations is presented. Since global thunderstorm activity is also well correlated with the earth's ionospheric potential, it appears that variations of ionospheric potential, that can be measured at a single location, may be able to supply valuable information regarding global surface temperature fluctuations. The observations presented enable a prediction that a 1 percent increase in global surface temperatures may result in a 20 percent increase in ionospheric potential.

  18. Global temperatures and the global warming ``debate''

    NASA Astrophysics Data System (ADS)

    Aubrecht, Gordon

    2009-04-01

    Many ordinary citizens listen to pronouncements on talk radio casting doubt on anthropogenic global warming. Some op-ed columnists likewise cast doubts, and are read by credulous citizens. For example, on 8 March 2009, the Boston Globe published a column by Jeff Jacoby, ``Where's global warming?'' According to Jacoby, ``But it isn't such hints of a planetary warming trend that have been piling up in profusion lately. Just the opposite.'' He goes on to write, ``the science of climate change is not nearly as important as the religion of climate change,'' and blamed Al Gore for getting his mistaken views accepted. George Will at the Washington Post also expressed denial. As a result, 44% of U.S. voters, according to the January 19 2009 Rasmussen Report, blame long-term planetary trends for global warming, not human beings. Is there global cooling, as skeptics claim? We examine the temperature record.

  19. Coastal eutrophication and temperature variation

    SciTech Connect

    Ganoulis, J.; Rafailidis, S.; Bogardi, I.; Duckstein, L.; Matyasovszky, I.

    1994-12-31

    A 3-D hydroecological model has been developed to simulate the impact of climate-change-induced daily temperature variation on coastal water quality and eutrophication. Historical daily temperature time series over a thirty-year period have been used to link local meteorological variables to large-scale atmospheric circulation patterns (CPs). Then, CPs generated under a 2{times}CO{sub 2} scenario have been used to simulate climate-change-induced local daily temperature variations. Both historical and climate-change-induced temperature time series have been introduced as inputs into the hydroecological model to simulate coastal water quality and eutrophication. Subject to model validation with available data, a case study in the bay of Thessaloniki (N. Greece) indicates a risk of increasing eutrophication and oxygen depletion in coastal areas due to possible climate change.

  20. Global Color Variations on Io

    NASA Astrophysics Data System (ADS)

    Geissler, P. E.; McEwen, A. S.; Simonelli, D. P.; Lopes-Gautier, R.; Davies, A. G.; Granahan, J.; Denk, T.; Galileo Imaging Team

    1997-07-01

    Galileo multispectral imaging of Io augments existing Voyager color data by extending the sensitivity of the observations to near-infrared wavelengths. Global 4-color coverage was obtained during Galileo's first two orbits, at resolutions ranging from 10 to 23 km/pixel and phase angles from 4 to 55 degrees, and again during the 4th orbit with a similar range of resolutions and phase angles. We have used these data to derive the distribution of bright red, presumably pyroclastic deposits such as produced by the currently active plume Pele. This unit is indistinct in Voyager images but can be effectively mapped in the longer wavelength data from Galileo. The bright red materials appear to be associated with high temperature, low albedo edifices which show significant change between the Voyager and Galileo eras. Because of their association with regions of current or recent geologic activity, the bright red deposits are inferred to have been recently emplaced. Preliminary comparisons of Voyager and Galileo data suggest that the red materials fade over relatively short time scales, consistent with their interpretation [1] as metastable sulfur allotropes. Further analysis should allow us to quantify the rates of optical alteration and compare to possible mechanisms such as phase transformations, sublimation, and sputtering by charged particles. [1] Spencer, J., et al., Volcanic resurfacing of Io: Post-repair HST imaging, Icarus, in press, 1997.

  1. Interannual variation of global atmospheric angular momentum

    SciTech Connect

    Chen, Tsing-Chang; Yen, Ming-Cheng; Tribbia, J.J.

    1996-10-01

    The relative atmospheric angular momentum (RAM) integrated over the globe is an explicit variable representing the state of the atmospheric general circulation. After removing the annual, semiannual, and higher-frequency components, the filtered global RAM time series for the past 14 years (1979-92) is highly correlated with both the Southern Oscillation index and the tropical Pacific sea surface temperature averaged over Area NINO-3 (5{degrees}S-5{degrees}N, 150{degrees}W-90{degrees}W). The interannual variation of global RAM is coherent with the poleward propagation of RAM anomalies. The global RAM anomalies reach their minimum values when westerly anomalies emerge in the Tropics and higher latitudes during a cold El Nino-Southern Oscillation (ENSO) event. On the other hand, global RAM anomalies attain their maximum values when westerly anomalies arrive at the subtropics of both hemispheres during a warm ENSO event. It is demonstrated that the poleward propagation of RAM anomalies results from the flip-flop oscillation of the anomalous circulation between cold and warm ENSO events. 11 refs., 3 figs.

  2. MEx/SPICAM Dayside Exospheric Temperatures Derived from Airglow Emissions and Comparisons with Global Model Simulations: Do We Understand the Variations?

    NASA Astrophysics Data System (ADS)

    Bougher, S. W.; Stiepen, A.; Gerard, J. M.; Pawlowski, D. J.; Montmessin, F.

    2013-12-01

    For ten years now, the SPectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) instrument on board Mars Express has collected tangential limb dayglow observations of the CO Cameron bands (170-270 nm) and the CO2+ doublet emission lines (289 nm). The CO2+ emission arises from the relaxation of the CO2+* molecule in the B2Σ+ state to the X2Π state. The CO Cameron emissions arise from the forbidden transition between CO in the exited a3 Π triplet state to the ground (X1Σ+) state. CO2+*and CO* molecules are mainly produced in the Martian dayside through photoionization and photoelectron impact. The temperature of the neutral thermosphere-exosphere region of the Martian atmosphere (above 150 km) has been derived from the top scale height of these emission vertical profiles. The database contains temperatures obtained from observations that cover all latitudes, seasons, dayside solar zenith angles, etc. for solar minimum to moderate conditions. A search for the key factors that influence the temperature in this region of the Martian atmosphere is presented. In addition, 3-D global model simulations are conducted appropriate to these SPICAM sampling conditions. Comparisons among Mars Thermosphere General Circulation Model (MTGCM), Mars Global Ionosphere Thermosphere Model (MGITM), and SPICAM derived temperatures are made. The capability of these solar EUV controlled 3-D models to reproduce observed dayside temperatures is discussed.

  3. Change in global temperature: A statistical analysis

    SciTech Connect

    Richards, G.R. )

    1993-03-01

    This paper investigates several issues relating to global climatic change using statistical techniques that impose minimal restrictions on the data. The main findings are as follows: (1) The global temperature increase since the last century is a systematic development. (2) Short-term variations in temperature do not have long-lasting effects on the final realizations of the series over time, stochastic perturbations dissipate and temperature reverts to trend. (3) Multivariate tests for causality demonstrate that atmospheric CO[sub 2] is a significant forcing factor. The implied change in temperature with respect to a doubling of atmospheric CO[sub 2] lies in a range of 2.17[degrees] to 2.57[degrees]C, with a mean value of 2.34[degrees]C. The contributions of solar irradiance and volcanic loading are much smaller. (4) In a multivariate system, shocks to forcing factors generate stochastic cycles in temperature comparable to the results from unforced simulations of climatological models. (5) Extrapolation of regression equations predict changes in global temperature that are marginally lower than the results from climatological simulation models.

  4. Global Color Variations on Callisto

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Jupiter's icy moon Callisto is shown in approximate natural color (left) and in false color to enhance subtle color variations (right). This image of Callisto's Jupiter-facing hemisphere shows the ancient, multi-ring impact structure Valhalla just above the center of the image. Valhalla, possibly created by a large asteroid or comet which impacted Callisto, is the largest surface feature on this icy moon. Valhalla consists of a bright inner region, about 600 kilometers (360 miles) in diameter surrounded by concentric rings 3000 to 4000 kilometers (1800-2500 miles) in diameter. The bright central plains were possibly created by the excavation and ejection of 'cleaner' ice from beneath the surface, with a fluid-like mass (impact melt) filling the crater bowl after impact. The concentric rings are fractures in the crust resulting from the impact.

    The false color in the right image shows new information, including ejecta from relatively recent craters, which are often not apparent in the natural color image. The color also reveals a gradual variation across the moon's hemisphere, perhaps due to implantation of materials onto the surface from space.

    These color images were obtained with the 1 micrometer (infrared), green, and violet filters of the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. The false color is created from ratios of infrared/violet and its inverse (violet/infrared) which are then combined so the infrared/violet, green, and violet/infrared are assigned to red, green, and blue in a composite product.

    North is to the top of the picture and the sun illuminates the surface from near the center, in the same way a full moon is seen from Earth when illuminated by the sun. The image, centered at 0.5 degrees south latitude and 56.3 degrees longitude, covers an area about 4800 by 4800 kilometers. The resolution is 14 kilometers per picture element. The images were taken on November 5, 1997 at a range of 68,400 kilometers (41,000 miles

  5. Global variations of zonal mean ozone during stratospheric warming events

    NASA Technical Reports Server (NTRS)

    Randel, William J.

    1993-01-01

    Eight years of Solar Backscatter Ultraviolet (SBUV) ozone data are examined to study zonal mean variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50 deg in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.

  6. Global variations of zonal mean ozone during stratospheric warming events

    SciTech Connect

    Randel, W.J. )

    1993-10-01

    Eight years of Solar Backscatter Ultraviolet ozone data are examined to study zonal mean ozone variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50[degrees] in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of ozone-temperature sensitivity in the upper stratosphere. 39 refs., 16 rigs.

  7. Global variations of zonal mean ozone during stratospheric warming events

    NASA Technical Reports Server (NTRS)

    Randel, William J.

    1993-01-01

    Eight years of Solar Backscatter Ultraviolet (SBUV) ozone data are examined to study zonal mean variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50 deg in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.

  8. MODIS Global Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

  9. MODIS Global Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

  10. Climate variation explains a third of global crop yield variability

    PubMed Central

    Ray, Deepak K.; Gerber, James S.; MacDonald, Graham K.; West, Paul C.

    2015-01-01

    Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32–39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability. PMID:25609225

  11. Climate variation explains a third of global crop yield variability

    NASA Astrophysics Data System (ADS)

    Ray, Deepak K.; Gerber, James S.; MacDonald, Graham K.; West, Paul C.

    2015-01-01

    Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32-39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability.

  12. Climate variation explains a third of global crop yield variability.

    PubMed

    Ray, Deepak K; Gerber, James S; MacDonald, Graham K; West, Paul C

    2015-01-22

    Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32-39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability.

  13. Monitoring global monthly mean surface temperatures

    SciTech Connect

    Trenberth, K.E.; Hurrell, J.W. ); Christy, J.R. )

    1992-12-01

    An assessment is made of how well the monthly mean surface temperatures for the decade of the 1980s are known. The sources of noise in the data, the numbers of observations, and the spatial coverage are appraised for comparison with the climate signal, and different analyzed results are compared to see how reproducible they are. The data are further evaluated by comparing anomalies of near-global monthly mean surface temperatures with those of global satellite channel 2 microwave sounding unit (MSU) temperatures for 144 months from 1979 to 1990. Very distincitve patterns are seen in the correlation coefficients, which range from high (> 0.8) over the extratropical continents of the Northern Hemisphere, to moderate ([approximately] 0.5) over tropical and subtropical land areas, to very low over the southern oceans and tropical western Pacific. The physical difference between the two temperature measurements is one factor in these patterns. The correlation coefficient is a measure of the signal-to-noise ratio, and largest values are found where the climate signal is largest, but the spatial variation in the inherent noise in the surface observations over the oceans is the other major factor in accounting for the pattern. 42 refs., 12 figs., 4 tab.

  14. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Eikelboom, T.; van Vliet, M. T.; Van Beek, L. P.

    2011-12-01

    ERA40 re-analysis data. We compared our simulation results with daily temperature data from rivers and lakes (USGS, limited to the USA) and compared mean monthly temperatures with those recorded in the GEMS data set. Results show that the model is able to capture well the mean monthly surface temperature for the majority of the GEMS stations both in time as well as in space, while the inter-annual variability as derived from the USGS data was captured reasonably well. Results are poorest for the arctic rivers, possibly because the timing of ice-breakup is predicted too late in the year due to the lack of including a mechanical break-up mechanism. The spatio-temporal variation of water temperature reveals large temperature differences between water and atmosphere for the higher latitudes, while considerable lateral transport of heat can be observed for rivers crossing hydroclimatic zones such as the Nile, the Mississippi and the large rivers flowing into the Arctic. Overall, our model results show great promise for future projection of global fresh surface water temperature under global change.

  15. A global reference for human genetic variation.

    PubMed

    Auton, Adam; Brooks, Lisa D; Durbin, Richard M; Garrison, Erik P; Kang, Hyun Min; Korbel, Jan O; Marchini, Jonathan L; McCarthy, Shane; McVean, Gil A; Abecasis, Gonçalo R

    2015-10-01

    The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals from 26 populations using a combination of low-coverage whole-genome sequencing, deep exome sequencing, and dense microarray genotyping. We characterized a broad spectrum of genetic variation, in total over 88 million variants (84.7 million single nucleotide polymorphisms (SNPs), 3.6 million short insertions/deletions (indels), and 60,000 structural variants), all phased onto high-quality haplotypes. This resource includes >99% of SNP variants with a frequency of >1% for a variety of ancestries. We describe the distribution of genetic variation across the global sample, and discuss the implications for common disease studies.

  16. A global reference for human genetic variation

    PubMed Central

    2016-01-01

    The 1000 Genomes Project set out to provide a comprehensive description of common human genetic variation by applying whole-genome sequencing to a diverse set of individuals from multiple populations. Here we report completion of the project, having reconstructed the genomes of 2,504 individuals from 26 populations using a combination of low-coverage whole-genome sequencing, deep exome sequencing, and dense microarray genotyping. We characterized a broad spectrum of genetic variation, in total over 88 million variants (84.7 million single nucleotide polymorphisms (SNPs), 3.6 million short insertions/deletions (indels), and 60,000 structural variants), all phased onto high-quality haplotypes. This resource includes >99% of SNP variants with a frequency of >1% for a variety of ancestries. We describe the distribution of genetic variation across the global sample, and discuss the implications for common disease studies. PMID:26432245

  17. Toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus changes under a global warming perspective: Variations in air temperature and soil moisture content.

    PubMed

    González-Alcaraz, M Nazaret; van Gestel, Cornelis A M

    2016-12-15

    This study aimed to assess how the current global warming perspective, with increasing air temperature (20°C vs. 25°C) and decreasing soil moisture content (50% vs. 30% of the soil water holding capacity, WHC), affected the toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus. Enchytraeids were exposed for 21d to a dilution series of the agricultural soil with Lufa 2.2 control soil under four climate situations: 20°C+50% WHC (standard conditions), 20°C+30% WHC, 25°C+50% WHC, and 25°C+30% WHC. Survival, reproduction and bioaccumulation of As, Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn were obtained as endpoints. Reproduction was more sensitive to both climate factors and metal(loid) pollution. High soil salinity (electrical conductivity~3dSm(-1)) and clay texture, even without the presence of high metal(loid) concentrations, affected enchytraeid performance especially at drier conditions (≥80% reduction in reproduction). The toxicity of the agricultural soil increased at drier conditions (10% reduction in EC10 and EC50 values for the effect on enchytraeid reproduction). Changes in enchytraeid performance were accompanied by changes in As, Fe, Mn, Pb and Zn bioaccumulation, with lower body concentrations at drier conditions probably due to greater competition with soluble salts in the case of Fe, Mn, Pb and Zn. This study shows that apart from high metal(loid) concentrations other soil properties (e.g. salinity and texture) may be partially responsible for the toxicity of metal(loid)-polluted soils to soil invertebrates, especially under changing climate conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Variation in the urban vegetation, surface temperature, air temperature nexus.

    PubMed

    Shiflett, Sheri A; Liang, Liyin L; Crum, Steven M; Feyisa, Gudina L; Wang, Jun; Jenerette, G Darrel

    2017-02-01

    Our study examines the urban vegetation - air temperature (Ta) - land surface temperature (LST) nexus at micro- and regional-scales to better understand urban climate dynamics and the uncertainty in using satellite-based LST for characterizing Ta. While vegetated cooling has been repeatedly linked to reductions in urban LST, the effects of vegetation on Ta, the quantity often used to characterize urban heat islands and global warming, and on the interactions between LST and Ta are less well characterized. To address this need we quantified summer temporal and spatial variation in Ta through a network of 300 air temperature sensors in three sub-regions of greater Los Angeles, CA, which spans a coastal to desert climate gradient. Additional sensors were placed within the inland sub-region at two heights (0.1m and 2m) within three groundcover types: bare soil, irrigated grass, and underneath citrus canopy. For the entire study region, we acquired new imagery data, which allowed calculation of the normalized difference vegetation index (NDVI) and LST. At the microscale, daytime Ta measured along a vertical gradient, ranged from 6 to 3°C cooler at 0.1 and 2m, underneath tall canopy compared to bare ground respectively. At the regional scale NDVI and LST were negatively correlated (p<0.001). Relationships between diel variation in Ta and daytime LST at the regional scale were progressively weaker moving away from the coast and were generally limited to evening and nighttime hours. Relationships between NDVI and Ta were stronger during nighttime hours, yet effectiveness of mid-day vegetated cooling increased substantially at the most arid region. The effectiveness of vegetated Ta cooling increased during heat waves throughout the region. Our findings suggest an important but complex role of vegetation on LST and Ta and that vegetation may provide a negative feedback to urban climate warming.

  19. Global Surface Temperatures of the Moon

    NASA Astrophysics Data System (ADS)

    Williams, J. P.; Paige, D. A.; Greenhagen, B. T.; Sefton-Nash, E.

    2015-12-01

    The Diviner instrument aboard the Lunar Reconnaissance Orbiter (LRO) is providing the most comprehensive view of how regoliths on airless body store and exchange thermal energy with the space environment. Approximately a quarter trillion calibrated radiance measurements of the Moon, acquired over 5.5 years by Diviner, have been compiled into a 0.5° resolution global dataset with a 0.25 hour local time resolution. Maps generated with this dataset provide a global perspective of the surface energy balance of the Moon and reveal the complex and extreme nature of the lunar surface thermal environment. Daytime maximum temperatures are sensitive to the radiative properties of the surface and are ~387-397 K at the equator, dropping to ~95 K before sunrise. Asymmetry between the morning and afternoon temperatures is observed due to the thermal inertia of the regolith with the dusk terminator ~30 K warmer than the dawn terminator at the equator. An increase in albedo with incidence angle is required to explain the observed temperatures with latitude. At incidence angles >40° topography and surface roughness result in increasing anisothermality between spectral passbands and scatter in temperatures. Minimum temperatures reflect variations in thermophysical properties (Figure). Impact craters are found to modify regolith properties over large distances. The thermal signature of Tycho is asymmetric consistent with an oblique impact coming from the west. Some prominent crater rays are visible in the thermal data and require material with a higher thermal inertial than nominal regolith. The influence of the formation of the Orientale basin on the regolith properties is observable over a substantial portion of the western hemisphere despite its age (~3.8 Gyr), and may have contributed to mixing of highland and mare material on the southwest margin of Oceanus Procellarum where the gradient in radiative properties at the mare-highland contact are observed to be broad (~200 km).

  20. Circadian temperature variation and ageing.

    PubMed

    Weinert, Dietmar

    2010-01-01

    In the present paper, an attempt is made to summarize current knowledge concerning the daily body temperature rhythm and its age-dependent alterations. Homeostatic and circadian control mechanisms are considered. Special attention is paid to the circadian system, as the mechanisms of autonomic control are the topic of another contribution to this special issue. Also, the interactions of the core body temperature rhythm with other circadian functions are discussed in detail as they constitute an essential part of the internal temporal order of living systems and thus guarantee their optimal functioning. In the second part of the paper, age-dependent changes in the circadian body temperature rhythm and their putative causes, considering circadian and homeostatic components, are described. Consequences for health and fitness and some possibilities to prevent adverse effect are mentioned in the final section.

  1. Global Variation of Meteor Trail Plasma Turbulence

    NASA Technical Reports Server (NTRS)

    Dyrud, L. P.; Hinrichs, J.; Urbina, J.

    2011-01-01

    We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere will the resulting trail become plasma turbulent, what are the factors influencing the development of turbulence, and how do they vary on a global scale. Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars, and turbulence influences the evolution of specular radar meteor trails, particularly regarding the inference of mesospheric temperatures from trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and density, and ionospheric plasma density have on the variability of meteor trail evolution and the observation of nonspecular meteor trails, and demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends using non-specular and specular meteor trails.

  2. Variations of mesopause temperatures in Europe

    NASA Astrophysics Data System (ADS)

    Offermann, D.; Gerndt, R.; Lange, G.; Trinks, H.

    Mesopause temperatures were derived from ground measurements of the near infrared OH(asterisk) spectrum. Preliminary data are presented. Seasonal variations at Wuppertal (51 deg N, 7 deg E) are well represented if the Cole and Kantor (1978) model is raised by 10 K and shifted by about 18 days. Latitudinal variations from 68 deg N to 51 deg N are found much smaller than the model variations. During a stratospheric warming, mesopause and stratosphere temperatures were found to be in anticorrelation only if a substantial longitudinal shift is introduced.

  3. Global temperature evolution: recent trends and some pitfalls

    NASA Astrophysics Data System (ADS)

    Rahmstorf, Stefan; Foster, Grant; Cahill, Niamh

    2017-05-01

    Global surface temperatures continue to rise. In most surface temperature data sets, the years 2014, 2015 and again 2016 set new global heat records since the start of regular measurements. Never before have three record years occurred in a row. We show that this recent streak of record heat does not in itself provide statistical evidence for an acceleration of global warming, nor was it preceded by a ‘slowdown period’ with a significantly reduced rate of warming. Rather, the data are fully consistent with a steady global warming trend since the 1970s, superimposed with random, stationary, short-term variability. All recent variations in short-term trends are well within what was to be expected, based on the observed warming trend and the observed variability from the 1970s up to the year 2000. We discuss some pitfalls of statistical analysis of global temperatures which have led to incorrect claims of an unexpected or significant warming slowdown.

  4. Global surface temperature changes since the 1850s

    SciTech Connect

    Jones, P.D.

    1996-12-31

    Temperature data from land and marine areas form the basis for many studies of climatic variations on local, regional and hemispheric scales, and the global mean temperature is a fundamental measure of the state of the climate system. In this paper it is shown that the surface temperature of the globe has warmed by about 0.5{degrees}C since the mid-nineteenth century. This is an important part of the evidence in the {open_quote}global warming{close_quote} debate. How certain are we about the magnitude of the warming? Where has it been greatest? In this paper, these and related issues will be addressed.

  5. Monitoring Global Temperatures From Satellites

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1992-01-01

    Report provides evidence that passive microwave radiometry from satellites provides more-precise information on atmospheric temperatures than sparse distribution of thermometers. Accurate temperatures needed for detection of "greenhouse" warming, evaluation of computer models of change in climate, and for understanding important factors in climate system.

  6. Global Economic Exposure to Future Temperature Changes

    NASA Astrophysics Data System (ADS)

    Hsiang, S. M.

    2011-12-01

    In global-scale analyses of future climate change, "global average temperature change" is a commonly used summary statistic. Unfortunately, this statistic may not be useful for many types of economic analyses because it is an average over the planet's entire surface and is therefore dominated by changes over oceans and other uninhabited regions. Here, we attempt to summarize projected temperature changes in a manner that is more useful for economic analyses: we construct the distributions of future temperature exposure for a randomly selected person, a random hectare of cropland, and a random dollar of value-added. Our results streamline global cost analyses, enabling future studies to estimate global losses by combining their locally derived loss-functions with our estimates of global exposure. We demonstrate this application by estimating that low and middle income populations may suffer income losses of 9% annually due only to the effects of thermal stress on workers, a mechanism previously omitted from global cost estimates. In ancillary findings, we also document that (1) when exposure distributions are substituted for global average temperature change in standard models of economic costs, projected annual losses increase by trillions of dollars; (2) low and middle income populations will be twice as exposed to harmful temperatures as high income populations, based only on their locations; and (3) it is unlikely the direct effects of warming can have a positive net impact on the global economy.

  7. Rising Temperatures Reduce Global Wheat Production

    NASA Technical Reports Server (NTRS)

    Asseng, S.; Ewert, F.; Martre, P.; Rötter, R. P.; Lobell, D. B.; Cammarano, D.; Kimball, B. A.; Ottman, M. J.; Wall, G. W.; White, J. W.; Reynolds, M. P.; Alderman, P. D.; Prasad, P. V. V.; Aggarwal, P. K.; Anothai, J.; Basso, B.; Biernath, C.; Challinor, A. J.; De Sanctis, G.; Doltra, J.; Fereres, E.; Garcia-Vila, M.; Gayler, S.; Hoogenboom, G.; Hunt, L. A.; Izaurralde, R. C.; Jabloun, M.; C. D. Jones,; Kersebaum, K. C.; Koehler, A-K.; Müller, C.; Naresh Kumar, S.; Nendel, C.; O’Leary, G.; Olesen, J. E.; Palosuo, T.; Priesack, E.; Eyshi Rezaei, E.; Ruane, A. C.; Semenov, M. A.; Shcherbak, I.; Stöckle, C.; Stratonovitch, P.; Streck, T.; Supit, I.; Tao, F.; Thorburn, P. J.; Waha, K.; Wang, E.; Wallach, D.; Wolf, J.; Zhao, Z.; Zhu, Y.

    2015-01-01

    Crop models are essential tools for assessing the threat of climate change to local and global food production. Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature. Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32? degrees C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each degree C of further temperature increase and become more variable over space and time.

  8. Rising temperatures reduce global wheat production

    NASA Astrophysics Data System (ADS)

    Asseng, S.; Ewert, F.; Martre, P.; Rötter, R. P.; Lobell, D. B.; Cammarano, D.; Kimball, B. A.; Ottman, M. J.; Wall, G. W.; White, J. W.; Reynolds, M. P.; Alderman, P. D.; Prasad, P. V. V.; Aggarwal, P. K.; Anothai, J.; Basso, B.; Biernath, C.; Challinor, A. J.; de Sanctis, G.; Doltra, J.; Fereres, E.; Garcia-Vila, M.; Gayler, S.; Hoogenboom, G.; Hunt, L. A.; Izaurralde, R. C.; Jabloun, M.; Jones, C. D.; Kersebaum, K. C.; Koehler, A.-K.; Müller, C.; Naresh Kumar, S.; Nendel, C.; O'Leary, G.; Olesen, J. E.; Palosuo, T.; Priesack, E.; Eyshi Rezaei, E.; Ruane, A. C.; Semenov, M. A.; Shcherbak, I.; Stöckle, C.; Stratonovitch, P.; Streck, T.; Supit, I.; Tao, F.; Thorburn, P. J.; Waha, K.; Wang, E.; Wallach, D.; Wolf, J.; Zhao, Z.; Zhu, Y.

    2015-02-01

    Crop models are essential tools for assessing the threat of climate change to local and global food production. Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature. Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 °C to 32 °C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each °C of further temperature increase and become more variable over space and time.

  9. Rising Temperatures Reduce Global Wheat Production

    NASA Technical Reports Server (NTRS)

    Asseng, S.; Ewert, F.; Martre, P.; Rötter, R. P.; Lobell, D. B.; Cammarano, D.; Kimball, B. A.; Ottman, M. J.; Wall, G. W.; White, J. W.; hide

    2015-01-01

    Crop models are essential tools for assessing the threat of climate change to local and global food production. Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature. Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32? degrees C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each degree C of further temperature increase and become more variable over space and time.

  10. Monitoring global monthly mean surface temperatures

    NASA Technical Reports Server (NTRS)

    Trenberth, Kevin E.; Christy, John R.; Hurrell, James W.

    1992-01-01

    The accuracy of the global surface air temperature (SST) estimates for a particular month over the past decade is assessed using all of the in situ observations available today. The sources of noise in the data, the numbers of observations, and the spatial coverage are appraised for the comparison with the climate signal, and different analyzed results are compared to determine their reproducibility. The data are further evaluated by comparing anomalies of near-global monthly mean surface temperatures with those of global satellite channel 2 microwave sounding unit temperatures for 144 months from 1979 to 1990. The results indicate that the inherent noise level in an SST observation is about 1.0 C, and this is compounded when the observation is made in regions of large temperature gradient.

  11. Global color and albedo variations on Io

    USGS Publications Warehouse

    McEwen, A.S.

    1988-01-01

    Three multispectral mosaics of Io have been produced from Voyager imaging data: a global mosaic from each of the Voyager 1 and Voyager 2 data sets and a high-resolution mosaic of the region surrounding the volcano Ra Patera. The mosaics are maps of normal albedo and color in accurate geometric map formats. Io's photometric behavior, mapped with a two-image technique, is spatially variable, especially in the bright white areas. The disk-integrated color and albedo of the satellite have been remarkably constant over recent decades, despite the volcanic activity and the many differences between Voyager 1 and 2 images (acquired just 4 months apart). This constancy is most likely due to the consistent occurrence of large Pele-type plumes with relatively dark, red deposits in the region from long 240 to 360??. A transient brightening southeast of Pele during the Voyager 1 encounter was probably due to real changes in surface and/or atmospheric materials, rather than to photometric behavior. The intrinsic spectral variability of Io, as seen in a series of two-dimensional histograms of the multispectral mosaics, consists of continuous variation among three major spectral end members. The data were mapped into five spectral units to compare them with laboratory measurements of candidate surface materials and to show the planimetric distributions. Unit 1 is best fit by the spectral reflectance of ordinary elemental sulfur, and it is closely associated with the Peletype plume deposits. Unit 2 is strongly confined to the polar caps above about latitude ??50??, but its composition is unknown. Unit 5 is probably SO2 with relatively minor contamination; it is concentrated in the equatorial region and near the long-lived Prometheus-type plumes. Units 3 and 4 are gradational between units 1 and 5. In addition to SO2 and elemental sulfur, other plausible components of the surface are polysulfur oxides, FeCl2, Na2S, and NaHS. ?? 1988.

  12. Modeling of global surface air temperature

    NASA Astrophysics Data System (ADS)

    Gusakova, M. A.; Karlin, L. N.

    2012-04-01

    A model to assess a number of factors, such as total solar irradiance, albedo, greenhouse gases and water vapor, affecting climate change has been developed on the basis of Earth's radiation balance principle. To develop the model solar energy transformation in the atmosphere was investigated. It's a common knowledge, that part of the incoming radiation is reflected into space from the atmosphere, land and water surfaces, and another part is absorbed by the Earth's surface. Some part of outdoing terrestrial radiation is retained in the atmosphere by greenhouse gases (carbon dioxide, methane, nitrous oxide) and water vapor. Making use of the regression analysis a correlation between concentration of greenhouse gases, water vapor and global surface air temperature was obtained which, it is turn, made it possible to develop the proposed model. The model showed that even smallest fluctuations of total solar irradiance intensify both positive and negative feedback which give rise to considerable changes in global surface air temperature. The model was used both to reconstruct the global surface air temperature for the 1981-2005 period and to predict global surface air temperature until 2030. The reconstructions of global surface air temperature for 1981-2005 showed the models validity. The model makes it possible to assess contribution of the factors listed above in climate change.

  13. Observed seasonal variations in exospheric effective temperatures

    NASA Astrophysics Data System (ADS)

    Mierkiewicz, E. J.; Roesler, F. L.; Nossal, S. M.

    2012-06-01

    High spectral resolution line profile observations indicate a reproducible semi-annual variation in the geocoronal hydrogen Balmer α effective temperature. These observations were made between 08 January 2000 and 21 November 2001 from Pine Bluff Observatory (WI) with a second generation double etalon Fabry-Perot annular summing spectrometer operating at a resolving power of 80,000. This data set spans sixty-four nights of observations (1404 spectra in total) over 20 dark-moon periods. A two cluster Gaussian model fitting procedure is used to determine Doppler line widths, accounting for fine structure contributions to the line, including those due to cascade; cascade contributions at Balmer α are found to be 5 ± 3%. An observed decrease in effective temperature with increasing shadow altitude is found to be a persistent feature for every night in which a wide range of shadow altitudes were sampled. A semiannual variation is observed in the column exospheric effective temperature with maxima near day numbers 100 and 300 and minima near day numbers 1 and 200. Temperatures ranged from ˜710 to 975 K. Average MSIS model exobase temperatures for similar conditions are approximately 1.5× higher than those derived from the Balmer α observations, a difference likely due to contributions to the observed Balmer α column emission from higher, cooler regions of the exosphere.

  14. Global latitudinal variations in marine copepod diversity and environmental factors.

    PubMed

    Rombouts, Isabelle; Beaugrand, Grégory; Ibanez, Frédéric; Gasparini, Stéphane; Chiba, Sanae; Legendre, Louis

    2009-09-07

    Latitudinal gradients in diversity are among the most striking features in ecology. For terrestrial species, climate (i.e. temperature and precipitation) is believed to exert a strong influence on the geographical distributions of diversity through its effects on energy availability. Here, we provide the first global description of geographical variation in the diversity of marine copepods, a key trophic link between phytoplankton and fish, in relation to environmental variables. We found a polar-tropical difference in copepod diversity in the Northern Hemisphere where diversity peaked at subtropical latitudes. In the Southern Hemisphere, diversity showed a tropical plateau into the temperate regions. This asymmetry around the Equator may be explained by climatic conditions, in particular the influence of the Inter-Tropical Convergence Zone, prevailing mainly in the northern tropical region. Ocean temperature was the most important explanatory factor among all environmental variables tested, accounting for 54 per cent of the variation in diversity. Given the strong positive correlation between diversity and temperature, local copepod diversity, especially in extra-tropical regions, is likely to increase with climate change as their large-scale distributions respond to climate warming.

  15. Global temperature distributions from OGO-6 6300 A airglow measurements

    NASA Technical Reports Server (NTRS)

    Blamont, J. E.; Luton, J. M.; Nisbet, J. S.

    1974-01-01

    The OGO-6 6300 A airglow temperature measurements have been used to develop models of the global temperature distributions under solstice and equinox conditions for the altitude region from 240 to 300 km and for times ranging from dawn in this altitude region to shortly after sunset. The distributions are compared with models derived from satellite orbital decay and incoherent scatter sounding. The seasonal variation of the temperature as a function of latitude is shown to be very different from that derived from static diffusion models with constant boundary conditions.

  16. Global temperature distributions from OGO-6 6300 A airglow measurements

    NASA Technical Reports Server (NTRS)

    Blamont, J. E.; Luton, J. M.; Nisbet, J. S.

    1974-01-01

    The OGO-6 6300 A airglow temperature measurements have been used to develop models of the global temperature distributions under solstice and equinox conditions for the altitude region from 240 to 300 km and for times ranging from dawn in this altitude region to shortly after sunset. The distributions are compared with models derived from satellite orbital decay and incoherent scatter sounding. The seasonal variation of the temperature as a function of latitude is shown to be very different from that derived from static diffusion models with constant boundary conditions.

  17. High Predictive Skill of Global Surface Temperature a Year Ahead

    NASA Astrophysics Data System (ADS)

    Folland, C. K.; Colman, A.; Kennedy, J. J.; Knight, J.; Parker, D. E.; Stott, P.; Smith, D. M.; Boucher, O.

    2011-12-01

    We discuss the high skill of real-time forecasts of global surface temperature a year ahead issued by the UK Met Office, and their scientific background. Although this is a forecasting and not a formal attribution study, we show that the main instrumental global annual surface temperature data sets since 1891 are structured consistently with a set of five physical forcing factors except during and just after the second World War. Reconstructions use a multiple application of cross validated linear regression to minimise artificial skill allowing time-varying uncertainties in the contribution of each forcing factor to global temperature to be assessed. Mean cross validated reconstructions for the data sets have total correlations in the range 0.93-0.95,interannual correlations in the range 0.72-0.75 and root mean squared errors near 0.06oC, consistent with observational uncertainties.Three transient runs of the HadCM3 coupled model for 1888-2002 demonstrate quite similar reconstruction skill from similar forcing factors defined appropriately for the model, showing that skilful use of our technique is not confined to observations. The observed reconstructions show that the Atlantic Multidecadal Oscillation (AMO) likely contributed to the re-commencement of global warming between 1976 and 2010 and to global cooling observed immediately beforehand in 1965-1976. The slowing of global warming in the last decade is likely to be largely due to a phase-delayed response to the downturn in the solar cycle since 2001-2, with no net ENSO contribution. The much reduced trend in 2001-10 is similar in size to other weak decadal temperature trends observed since global warming resumed in the 1970s. The causes of variations in decadal trends can be mostly explained by variations in the strength of the forcing factors. Eleven real-time forecasts of global mean surface temperature for the year ahead for 2000-2010, based on broadly similar methods, provide an independent test of the

  18. Global variations in abyssal peridotite compositions

    NASA Astrophysics Data System (ADS)

    Warren, Jessica M.

    2016-04-01

    Abyssal peridotites are ultramafic rocks collected from mid-ocean ridges that are the residues of adiabatic decompression melting. Their compositions provide information on the degree of melting and melt-rock interaction involved in the formation of oceanic lithosphere, as well as providing constraints on pre-existing mantle heterogeneities. This review presents a compilation of abyssal peridotite geochemical data (modes, mineral major elements, and clinopyroxene trace elements) for > 1200 samples from 53 localities on 6 major ridge systems. On the basis of composition and petrography, peridotites are classified into one of five lithological groups: (1) residual peridotite, (2) dunite, (3) gabbro-veined and/or plagioclase-bearing peridotite, (4) pyroxenite-veined peridotite, and (5) other types of melt-added peridotite. Almost a third of abyssal peridotites are veined, indicating that the oceanic lithospheric mantle is more fertile, on average, than estimates based on residual peridotites alone imply. All veins appear to have formed recently during melt transport beneath the ridge, though some pyroxenites may be derived from melting of recycled oceanic crust. A limited number of samples are available at intermediate and fast spreading rates, with samples from the East Pacific Rise indicating high degrees of melting. At slow and ultra-slow spreading rates, residual abyssal peridotites define a large (0-15% modal clinopyroxene and spinel Cr# = 0.1-0.6) compositional range. These variations do not match the prediction for how degree of melting should vary as a function of spreading rate. Instead, the compositional ranges of residual peridotites are derived from a combination of melting, melt-rock interaction and pre-existing compositional variability, where melt-rock interaction is used here as a general term to refer to the wide range of processes that can occur during melt transport in the mantle. Globally, ~ 10% of abyssal peridotites are refractory (0

  19. Joint variability of global runoff and global sea surface temperatures

    USGS Publications Warehouse

    McCabe, G.J.; Wolock, D.M.

    2008-01-01

    Global land surface runoff and sea surface temperatures (SST) are analyzed to identify the primary modes of variability of these hydroclimatic data for the period 1905-2002. A monthly water-balance model first is used with global monthly temperature and precipitation data to compute time series of annual gridded runoff for the analysis period. The annual runoff time series data are combined with gridded annual sea surface temperature data, and the combined dataset is subjected to a principal components analysis (PCA) to identify the primary modes of variability. The first three components from the PCA explain 29% of the total variability in the combined runoff/SST dataset. The first component explains 15% of the total variance and primarily represents long-term trends in the data. The long-term trends in SSTs are evident as warming in all of the oceans. The associated long-term trends in runoff suggest increasing flows for parts of North America, South America, Eurasia, and Australia; decreasing runoff is most notable in western Africa. The second principal component explains 9% of the total variance and reflects variability of the El Ni??o-Southern Oscillation (ENSO) and its associated influence on global annual runoff patterns. The third component explains 5% of the total variance and indicates a response of global annual runoff to variability in North Aflantic SSTs. The association between runoff and North Atlantic SSTs may explain an apparent steplike change in runoff that occurred around 1970 for a number of continental regions.

  20. Global patterns of shallow groundwater temperatures

    NASA Astrophysics Data System (ADS)

    Benz, Susanne A.; Bayer, Peter; Blum, Philipp

    2017-03-01

    Only meters below our feet, shallow aquifers serve as sustainable energy source and provide freshwater storage and ecological habitats. All of these aspects are crucially impacted by the thermal regime of the subsurface. Due to the limited accessibility of aquifers however, temperature measurements are scarce. Most commonly, shallow groundwater temperatures are approximated by adding an offset to annual mean surface air temperatures. Yet, the value of this offset is not well defined, often arbitrarily set, and rarely validated. Here, we propose the usage of satellite-derived land surface temperatures instead of surface air temperatures. 2 548 measurement points in 29 countries are compiled, revealing characteristic trends in the offset between shallow groundwater temperatures and land surface temperatures. Here it is shown that evapotranspiration and snow cover impact on this offset globally, through latent heat flow and insulation. Considering these two processes only, global shallow groundwater temperatures are estimated in a resolution of approximately 1 km × 1 km. When comparing these estimated groundwater temperatures with measured ones a coefficient of determination of 0.95 and a root mean square error of 1.4 K is found.

  1. Global trends of measured surface air temperature

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lebedeff, Sergej

    1987-01-01

    The paper presents the results of surface air temperature measurements from available meteorological stations for the period of 1880-1985. It is shown that the network of meteorological stations is sufficient to yield reliable long-term, decadal, and interannual temperature changes for both the Northern Hemisphere and the Southern Hemisphere, despite the fact that most stations are located on the continents. The results indicate a global warming of about 0.5-0.7 C in the past century, with warming of similar magnitude in both hemispheres. A strong warming trend between 1965 and 1980 raised the global mean temperature in 1980 and 1981 to the highest level in the period of instrumental records. Selected graphs of the temperature change in each of the eight latitude zones are included.

  2. Global trends of measured surface air temperature

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lebedeff, Sergej

    1987-01-01

    The paper presents the results of surface air temperature measurements from available meteorological stations for the period of 1880-1985. It is shown that the network of meteorological stations is sufficient to yield reliable long-term, decadal, and interannual temperature changes for both the Northern Hemisphere and the Southern Hemisphere, despite the fact that most stations are located on the continents. The results indicate a global warming of about 0.5-0.7 C in the past century, with warming of similar magnitude in both hemispheres. A strong warming trend between 1965 and 1980 raised the global mean temperature in 1980 and 1981 to the highest level in the period of instrumental records. Selected graphs of the temperature change in each of the eight latitude zones are included.

  3. Circadian variations in body temperature during dialysis.

    PubMed

    Usvyat, Len A; Kotanko, Peter; van der Sande, Frank M; Kooman, Jeroen P; Carter, Mary; Leunissen, Karel M L; Levin, Nathan W

    2012-03-01

    Thermal changes during dialysis strongly influence intra-dialytic hemodynamics. The mechanisms behind the increase in body temperature during hemodialysis (HD) are still not completely understood. The objective of this retrospective observational cohort study is to assess the effect of circadian variation on body temperature changes during HD by comparing results in patients treated on different treatment shifts. Data from the Renal Research Institute, New York, clinical database encompassing patients treated in six states in the USA were used. Data from January and August 2008 were used for analysis. Body temperature changes during HD were categorized by dialysis shifts. Patients with morning shifts (n = 1064), afternoon shifts (n = 730) and evening shifts (n = 210) were compared. Pre-dialysis body temperatures were significantly different among the different shifts [morning, 36.41 (95% confidence interval: 36.39-36.43°C), afternoon, 36.47 (36.45-36.49°C), evening, 36.67 (36.64-36.70°C), P < 0.001]. In August, but not in January, intra-dialytic increases in body temperature were significantly different between patients treated during morning [0.07 (0.058-0.082°C)], afternoon [0.03 (0.016-0.044°C)] and evening shifts [-0.01 (-0.032 to 0.012°C); P < 0.001 analysis of variance], although in January, treatment shift was a significant predictor of the intra-dialytic increase in body temperature. The intra-dialytic change in body temperature was related not only to the pre-dialysis body temperature (r(2) = 0.31; P < 0.001) but also to microbiological dialysate quality, treatment time and dialysate temperature. The intra-dialytic change in blood pressure (BP) was significantly related to changes in intra-dialytic body temperature irrespective of the study month. Both pre-dialytic body temperature as well as changes in body temperature are significantly related to the timing of the dialysis shifts, in phase with the circadian body temperature rhythm. Due to the

  4. Global variation of carbon use efficiency in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Tang, Xiaolu; Carvalhais, Nuno; Moura, Catarina; Reichstein, Markus

    2017-04-01

    Carbon use efficiency (CUE), defined as the ratio between net primary production (NPP) and gross primary production (GPP), is an emergent property of vegetation that describes its effectiveness in storing carbon (C) and is of significance for understanding C biosphere-atmosphere exchange dynamics. A constant CUE value of 0.5 has been widely used in terrestrial C-cycle models, such as the Carnegie-Ames-Stanford-Approach model, or the Marine Biological Laboratory/Soil Plant-Atmosphere Canopy Model, for regional or global modeling purposes. However, increasing evidence argues that CUE is not constant, but varies with ecosystem types, site fertility, climate, site management and forest age. Hence, the assumption of a constant CUE of 0.5 can produce great uncertainty in estimating global carbon dynamics between terrestrial ecosystems and the atmosphere. Here, in order to analyze the global variations in CUE and understand how CUE varies with environmental variables, a global database was constructed based on published data for crops, forests, grasslands, wetlands and tundra ecosystems. In addition to CUE data, were also collected: GPP and NPP; site variables (e.g. climate zone, site management and plant function type); climate variables (e.g. temperature and precipitation); additional carbon fluxes (e.g. soil respiration, autotrophic respiration and heterotrophic respiration); and carbon pools (e.g. stem, leaf and root biomass). Different climate metrics were derived to diagnose seasonal temperature (mean annual temperature, MAT, and maximum temperature, Tmax) and water availability proxies (mean annual precipitation, MAP, and Palmer Drought Severity Index), in order to improve the local representation of environmental variables. Additionally were also included vegetation phenology dynamics as observed by different vegetation indices from the MODIS satellite. The mean CUE of all terrestrial ecosystems was 0.45, 10% lower than the previous assumed constant CUE of 0

  5. Temperature Variations in Spain Since 1901: a Preliminary Analysis

    NASA Astrophysics Data System (ADS)

    Oñate, Juan J.; Pou, Antonio

    1996-07-01

    The long-term temperature trends since 1901 at ten meteorological stations on the Iberian Peninsula and one in the Canary Islands are analysed. These trends are identified by applying the Mann-Kendall trend test to the series of maximum and minimum temperatures, the variability of both, and the diurnal temperature range. A multidimensional scaling analysis is used to produce an automatic grouped systemization of all trends.The results appear to confirm the hypothesis of a local regionalization of the more global influences, yielding three types of regional trends in temperature variations since 1901: (i) less extreme in the north and north-west; (ii) more extreme conditions in the south-east and centre-east; and (iii) an overall increase in the south-west.

  6. A physically based model of global freshwater surface temperature

    NASA Astrophysics Data System (ADS)

    Beek, Ludovicus P. H.; Eikelboom, Tessa; Vliet, Michelle T. H.; Bierkens, Marc F. P.

    2012-09-01

    the Arctic rivers because the timing of ice breakup is predicted too late in the year due to the lack of including a mechanical breakup mechanism. Moreover, surface water temperatures for tropical rivers were overestimated, most likely due to an overestimation of rainfall temperature and incoming shortwave radiation. The spatiotemporal variation of water temperature reveals large temperature differences between water and atmosphere for the higher latitudes, while considerable lateral transport of heat can be observed for rivers crossing hydroclimatic zones, such as the Nile, the Mississippi, and the large rivers flowing to the Arctic. Overall, our model results show promise for future projection of global surface freshwater temperature under global change.

  7. Estimating pre-industrial global temperature

    NASA Astrophysics Data System (ADS)

    Hawkins, Ed; Ortega, Pablo; Suckling, Emma; Schurer, Andrew; Hegerl, Gabi; Jones, Phil; Joshi, Manoj; Osborn, Tim; Mignot, Juliette; Thorne, Peter; van Oldenborgh, Geert Jan

    2016-04-01

    The United Nations Framework Convention on Climate Change (UNFCCC) process has recently agreed to try and limit global temperature rise to `well below 2°C above pre-industrial levels'. But what period is `pre-industrial'? Remarkably, perhaps, this is not defined within the UNFCCC or its many agreements and protocols. Neither was the term used in the IPCC's fifth assessment report (AR5) when discussing when particular temperature levels might be reached, due to the lack of a robust definition. Here, we discuss the important factors to consider when defining a period to call pre-industrial, based on estimates of historical radiative forcings and the availability of climate observations. There is no perfect period to choose, but we suggest that 1720-1800 is the optimal choice. We also attempt to estimate the change in global temperatures since this pre-industrial period using a range of approaches based on observations, radiative forcings, global climate model simulations and proxy evidence. We discuss how such an assessment might be improved in future and conclude that 2015 was likely the first year in which global temperatures were more than 1°C above pre-industrial levels.

  8. Global water cycle and solar activity variations

    NASA Astrophysics Data System (ADS)

    Al-Tameemi, Muthanna A.; Chukin, Vladimir V.

    2016-05-01

    The water cycle is the most active and most important component in the circulation of global mass and energy in the Earth system. Furthermore, water cycle parameters such as evaporation, precipitation, and precipitable water vapour play a major role in global climate change. In this work, we attempt to determine the impact of solar activity on the global water cycle by analyzing the global monthly values of precipitable water vapour, precipitation, and the Solar Modulation Potential in 1983-2008. The first object of this study was to calculate global evaporation for the period 1983-2008. For this purpose, we determined the water cycle rate from satellite data, and precipitation/evaporation relationship from 10 years of Planet Simulator model data. The second object of our study was to investigate the relationship between the Solar Modulation Potential (solar activity index) and the evaporation for the period 1983-2008. The results showed that there is a relationship between the solar modulation potential and the evaporation values for the period of study. Therefore, we can assume that the solar activity has an impact on the global water cycle.

  9. Global Cooling: Effect of Urban Albedo on Global Temperature

    SciTech Connect

    Akbari, Hashem; Menon, Surabi; Rosenfeld, Arthur

    2007-05-22

    In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). The roof and the pavement albedo can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60%. We estimate U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills. Increasing albedo of urban surfaces can reduce the summertime urban temperature and improve the urban air quality. Increasing the urban albedo has the added benefit of reflecting more of the incoming global solar radiation and countering the effect of global warming. We estimate that increasing albedo of urban areas by 0.1 results in an increase of 3 x 10{sup -4} in Earth albedo. Using a simple global model, the change in air temperature in lowest 1.8 km of the atmosphere is estimated at 0.01K. Modelers predict a warming of about 3K in the next 60 years (0.05K/year). Change of 0.1 in urban albedo will result in 0.01K global cooling, a delay of {approx}0.2 years in global warming. This 0.2 years delay in global warming is equivalent to 10 Gt reduction in CO2 emissions.

  10. Increasing Temperature Extremes during the Recent Global Warming Hiatus

    NASA Astrophysics Data System (ADS)

    Johnson, N. C.; Kosaka, Y.; Xie, S. P.

    2015-12-01

    Although the recent global warming hiatus has featured a slowdown in the annual, global mean surface air temperature trend, temperature extremes have exhibited contrasting changes, as both wintertime cold and summertime hot extremes have increased over Northern Hemisphere (NH) land from 2002-2014. To investigate the sources of NH temperature extreme variability, we use multiple linear regression analysis that includes as predictors the typical drivers of global-scale climate variability - tropical Pacific sea surface temperatures (SST), volcanic aerosols, solar variability, and the linear time trend. This analysis suggests that natural forcings, including tropical SSTs and solar variations, have contributed to the recent increase in NH winter cold extremes. The magnitude of the recent increase in summer hot extremes is only captured after including an additional SST predictor for a pattern that resembles the Atlantic Multidecadal Oscillation, which suggests the importance of Atlantic Ocean SSTs for recent increases in hot extremes. When the regression models are applied to local, grid point scales, they indicate the promise for substantial skill in seasonal predictions of extreme temperature over some NH regions. Overall, this work reveals important sources of natural variability in extreme temperature trends superimposed upon the long-term increase of hot extremes and decrease of cold extremes.

  11. Stellar luminosity variations and global warming.

    PubMed

    Foukal, P

    1994-04-08

    Recent studies indicate that variation in the sun's luminosity is less than that observed in many other stars of similar magnetic activity. Current findings also indicate that in more active stars, the attenuation by faculae of sunspot luminosity modulation is less effective than in the sun at present. The sun could thus become photometrically more variable (and dimmer) if its magnetic activity exceeded present levels. But the levels of solar activity required for this to occur are not observed in carbon-14 and beryllium-10 records over the past several millennia, which indicates that such an increase in amplitude of surface magnetism-driven variations in solar luminosity is unlikely in the present epoch.

  12. Analysis of global and hemispheric temperature records and prognosis

    NASA Astrophysics Data System (ADS)

    Werner, Rolf; Valev, Dimitar; Danov, Dimitar; Guineva, Veneta; Kirillov, Andrey

    2015-06-01

    Climate changes are connected to long term variations of global and hemispheric temperatures, which are important for the work out of socio-political strategy for the near future. In the paper the annual temperature time series are modeled by linear multiple regression to identify important climate forcings including external climate factors such as atmospheric CO2 content, volcanic emissions, and the total solar irradiation as well as internal factors such as El Niño-Southern oscillation, Pacific decadal oscillation and Atlantic multidecadal oscillation. Adjusted temperatures were determined by removal of all significant influences except CO2. The adjusted temperatures follow a linear dependence toward the logarithm of the CO2 content, and the coefficient of determination is about 0.91. The evolution of the adjusted temperatures suggests that the warming due to CO2 from the beginning of the studied here time interval in 1900 has never stopped and is going on up to now. The global warming rate deduced from the adjusted temperatures since 1980 is about 0.14 ± 0.02 °C/decade. The warming rate reported in the IPCC assessment report 4 based on observed global surface temperature set is about 20% higher, due to the warming by the Atlantic multidecadal oscillation additional to the anthropogenic warming. The predicted temperature evolution based on long time changes of CO2 and the Atlantic multidecadal oscillation index shows that the Northern Hemispheric temperatures are modulated by the Atlantic multidecadal oscillation influence and will not change significantly to about 2040, after that they will increase speedily, just like during the last decades of the past century. The temperatures of the Southern Hemisphere will increase almost linearly and don't show significant periodic changes due to Atlantic multidecadal oscillation. The concrete warming rates of course are strongly depending on the future atmospheric CO2 content.

  13. Effects of Fertile Mantle Compositional Variation and Spreading Rate Variation on the Working of Global Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Niu, Y.; O'Hara, M. J.

    2014-12-01

    Mantle temperature variation, plate spreading rate variation and mantle compositional variation have been considered to be the three fundamental variables that govern the working of global ocean ridges [1]. An analysis demonstrates that mantle compositional variation exerts the primary control on ocean ridge processes; it determines (1) variation in both composition and mode of mantle mineralogy, (2) variation of mantle density, (3) variation of ridge axial depth, (4) source-inherited MORB compositional variation, (4) density-controlled variation in the amplitude of mantle upwelling, (5) apparent variation in the extent of melting, and (6) the correlated variation of MORB chemistry with ridge axial depth [2]. The above interpretations are reinforced by the updated MORB database [3]. The new database also confirms spreading rate control on the extent of melting as shown previously [4]. Mantle temperature variation could play a part, but its overstated role [3,5] results from a basic error (1) in treating ridge axial depth variation as evidence of mantle temperature variation by ignoring the intrinsic control of mantle composition, (2) in treating "mantle plume" influenced ridges (e.g., Iceland) as normal ridges of plate spreading origin, and (3) in treating low Vs at greater depths (> 300 km vs. < 200 km beneath ridges) beneath these "mantle plume" influenced ridges as evidence for hot ridge mantle. In order to understand the working of global ocean ridges, we must avoid plume-influenced ridges (e.g., in the vicinity of Iceland) and remove/average out data from such ridges. As a result, the correlations (e.g., between ridge axial depth, mantle low Vs anomaly, and some geochemical parameters) required for the interpretation of mantle temperature control all disappear. There is thus no evidence for large mantle temperature variation away from ridges influenced by "mantle plumes". References: [1] Niu et al., 2001, Earth Planet Sci. Lett., 186, 383-399; [2] Niu & O

  14. Possibility to explain global climate variations by earthquakes influence

    NASA Astrophysics Data System (ADS)

    Molchanov, O.

    2009-12-01

    An additional natural source of the global warming could be heat flux from seismicity. Estimated earthquakes energy release in the near-equatorial Pacific area during a year ≈ 1020 J that is equivalent to the energy released in the detonation about one million atomic bombs of Hiroshima class and produce average power flux due to seismicity ≈ 0.3-1 W/m2 . We have analyzed together the slow climate temperature variations in the near-equatorial Pacific Ocean area (SSTOI indices) and crustal seismic activity in the same region during 1973-2008 time period using correlation analysis and found similarity in seismic and ENSO periodicities (the latter with time lag about 1.5 years). Trends of the processes are also similar showing about 2 times increase in average seismic energy release during the whole period of analysis and conventional 0.10C/(10 years) increase in SSTOI index anomalies. Our main conclusion is on real possibility of climate-seismicity coupling. It is rather probable that at least partially climate ENSO oscillations and temperature anomaly trends are induced by similar variation in seismicity. A mechanism of several years periodicity in the seismic activity is unclear at present. Probably it is initiated in the upper mantle of the Earth (depth 600-700 km) and then penetrates in the crust as so-called deformation (or stress) wave with time delay from 3 to 10 years [1] [1] O.A. Molchanov and S. Uyeda, Upward migration of earthquake hypocenters in Japan,Kurile- Kamchatka and Sunda subduction zones, Physics and Chemistry of the Earth, 34, 423-430, 2009; doi:10.1016/j.pce.2008.09.011.

  15. Constraints on global temperature target overshoot

    NASA Astrophysics Data System (ADS)

    MacMartin, D. G.; Ricke, K.; Millar, R.

    2016-12-01

    The climate science and policy communities are beginning to assess the feasibility and potential benefits of limiting global warming to 1.5°C or 2°C. Understanding the dependence of the magnitude and duration of possible temporary exceedance (i.e., "overshoot") of these targets on sustainable energy decarbonization futures and carbon dioxide (CO2) removal rates will be an important contribution of the scientific community to this policy discussion. Drawing upon results from the mitigation literature and the IPCC Working Group 3 (WG3) scenario database, we examine the global mean temperature implications of differing independent pathways for the decarbonization of global energy supply and the implementation of negative emissions technologies. We find that within the range of decarbonization and negative emissions futures considered by WG3, the most ambitious rates of both decarbonization and deployment of negative emissions technologies are required to avoid overshoot of 1.5°C. The magnitude of temperature overshoot is more sensitive to the rate of decarbonization, but limiting the duration of overshoot to less than two centuries will require ambitious deployment of both decarbonization and negative emissions technology. The dependencies of temperature overshoots properties upon currently untested negative emissions technologies suggests that it will be important to assess how climate impacts depend on the magnitude and duration of overshoot, not just long term residual warming. As a new round of research proceeds with a 1.5°C threshold in mind, it will be important to understand the drivers behind various global temperature linked impacts and how these are influenced by both the duration and magnitude of a temporary overshoot of the target. This understanding will allow policy makers to better link climate policy goals to specific technological needs. Figure: Magnitude and duration of 1.5°C temperature target overshoot for "likely" range of climate response

  16. Global color and albedo variations on Triton

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1990-01-01

    Global multispectral mosaics of Triton have been produced from Voyager approach images; six spectral units are defined and mapped. The margin of the south polar cap (SPC) is scalloped and ranges in latitude from + 10 deg to -30 deg. A bright fringe is closely associated with the cap's margin; form it, diffuse bright rays extend north-northeast for hundreds of kilometers. Thus, the rays may consist of fringe materials that were redistributed by northward-going Coriolis-deflected winds. From 1977 to 1989, Triton's full-disk spectrum changed from markedly red and UV-dark to nearly neutral white and UV-bright. This spectral change can be explained by new deposition of nitrogen frost over both the northern hemisphere and parts of a formerly redder SPC. Frost deposition in the southern hemisphere during southern summer is possible over relatively high albedo areas of the cap (Stansberry et al., 1990), which helps to explain the apparent stability of the unexpectedly large SPC and the presence of the bright fringe.

  17. Variations in Global Precipitation: Climate-scale to Floods

    NASA Technical Reports Server (NTRS)

    Adler, Robert

    2006-01-01

    Variations in global precipitation from climate-scale to small scale are examined using satellite-based analyses of the Global Precipitation Climatology Project (GPCP) and information from the Tropical Rainfall Measuring Mission (TRMM). Global and large regional rainfall variations and possible long-term changes are examined using the 27- year (1979-2005) monthly dataset from the GPCP. In addition to global patterns associated with phenomena such as ENSO, the data set is explored for evidence of longterm change. Although the global change of precipitation in the data set is near zero, the data set does indicate a small upward trend in the Tropics (25S-25N), especially over ocean. Techniques are derived to isolate and eliminate variations due to ENS0 and major volcanic eruptions and the significance of the trend is examined. The status of TRMM estimates is examined in terms of evaluating and improving the long-term global data set. To look at rainfall variations on a much smaller scale TRMM data is used in combination with observations from other satellites to produce a 3-hr resolution, eight-year data set for examination of weather events and for practical applications such as detecting floods. Characteristics of the data set are presented and examples of recent flood events are examined.

  18. Global Patterns in Leaf Respiration and its Temperature Response

    NASA Astrophysics Data System (ADS)

    Heskel, M.; Atkin, O. K.; O'Sullivan, O. S.; Reich, P. B.; Tjoelker, M. G.; Weerasinghe, L. K.; Penillard, A.; Egerton, J. J. G.; Creek, D.; Bloomfield, K. J.; Xiang, J.; Sinca, F.; Stangl, Z.; Martinez-de la Torre, A.; Griffin, K. L.; Huntingford, C.; Hurry, V.; Meir, P.; Turnbull, M.

    2015-12-01

    Leaf respiration (R) represents a massive flux of carbon to the atmosphere. Currently, neither physiological models nor terrestrial biosphere models are able to disentangle sources of variation in leaf R among different plant species and contrasting environments. Similarly, such models do not adequately describe the short-term temperature (T) response of R, which can lead to inaccurate representation of leaf R in simulation models of regional and global terrestrial carbon cyling. Even minor differences in the underlying basal rate of leaf R and/or shape of the T-response curve can significantly impact estimates of carbon released and stored in ecosystems. Given this, we recently assembled and analyzed two new global databases (arctic-to-tropics) of leaf R and its short-term T-dependence. The results highlight variation in basal leaf R among species and across global gradients in T and aridity, with leaf R at a standard T (e.g. 25°C) being greatest in plants growing in the cold, dry Arctic and lowest in the warm, moist tropics. Arctic plants also exhibit higher rates of leaf R at a given photosynthetic capacity or leaf N concentration than their tropical counterparts. The results also point to convergence in the short-term temperature response of respiration across biomes and plant functional types. The applicability and significance of the short-term T-response of R for simulation models of plant and ecosystem carbon fluxes will be discussed.

  19. A global monthly sea surface temperature climatology

    NASA Technical Reports Server (NTRS)

    Shea, Dennis J.; Trenberth, Kevin E.; Reynolds, Richard W.

    1992-01-01

    The paper presents a new global 2 deg x 2 deg monthly sea surface temperature (SST) climatology, referred here to as the Shea-Trenberth-Reynolds (STR) climatology, which was derived by modifying a 1950-1979-based SST climatology from the Climate Analysis Center (CAC), by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. A comparison of the STR climatology with the Alexander and Mobley SST climatology showed that the STR climatology is warmer in the Northern Hemisphere, and colder poleward of 45 deg S.

  20. A global monthly sea surface temperature climatology

    NASA Technical Reports Server (NTRS)

    Shea, Dennis J.; Trenberth, Kevin E.; Reynolds, Richard W.

    1992-01-01

    The paper presents a new global 2 deg x 2 deg monthly sea surface temperature (SST) climatology, referred here to as the Shea-Trenberth-Reynolds (STR) climatology, which was derived by modifying a 1950-1979-based SST climatology from the Climate Analysis Center (CAC), by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. A comparison of the STR climatology with the Alexander and Mobley SST climatology showed that the STR climatology is warmer in the Northern Hemisphere, and colder poleward of 45 deg S.

  1. Variational Tricomplex, Global Symmetries and Conservation Laws of Gauge Systems

    NASA Astrophysics Data System (ADS)

    Sharapov, Alexey A.

    2016-10-01

    Using the concept of variational tricomplex endowed with a presymplectic structure, we formulate the general notion of symmetry. We show that each generalized symmetry of a gauge system gives rise to a sequence of conservation laws that are represented by on-shell closed forms of various degrees. This extends the usual Noether's correspondence between global symmetries and conservation laws to the case of lower-degree conservation laws and not necessarily variational equations of motion. Finally, we equip the space of conservation laws of a given degree with a Lie bracket and establish a homomorphism of the resulting Lie algebra to the Lie algebra of global symmetries.

  2. Variations in FASST Predictions of Soil Surface Temperatures

    DTIC Science & Technology

    2006-04-01

    shows more variation in temperature with perturbations in incident solar radiation. That the low-albedo soil would have the hottest surface is...ER D C/ CR R EL T R -0 6 -9 Variations in FASST Predictions of Soil Surface Temperatures Lindamae Peck April 2006 C ol d R eg io n s...April 2006 Variations in FASST Predictions of Soil Surface Temperatures Lindamae Peck Cold Regions Research and Engineering Laboratory U.S

  3. Glacier fluctuations, global temperature and sea-level change

    NASA Astrophysics Data System (ADS)

    Leclercq, P. W.

    2012-02-01

    The current world-wide glacier retreat is a clear sign of global warming. In addition, glaciers contribute to sea-level rise as a consequence of the current retreat. In this thesis we use records of past glacier fluctuations to reconstruct past climate variations and the glacier contribution to sea-level change. Firstly, a coherent data set of world-wide glacier fluctuations over the past centuries is compiled. Most available information of glacier fluctuations concerns glacier length fluctuations. There is currently a large number of sources available, varying from field observations, satellite images and aerial photography to reconstructions from historical documents and geological evidence. The data set, resulting from the compilation of available data, contains 374 length records of glaciers from all continents and is described in Chapter 2. In Chapter 3, a climatic interpretation of the length fluctuations of Glaciar Frías is presented. This glacier in North Patagonia has the longest detailed length record in southern South America. The glacier behaviour is modelled with a simplified mass balance model that is coupled with a flow line model. A warming of North Patagonian climate with 1.16 °Csince the mid 17th century, or a decrease in precipitation of 34%, would best explain the observed retreat since 1639. Driving the glacier model with existing climate reconstructions shows that the uncertainties in these reconstructions are rather large. In addition, it appears that the length fluctuations are mainly driven by variations in temperature rather than variations in precipitation. The development of such detailed models is not feasible for all glaciers in the length fluctuations data set. In the next chapter a simplified approach is used to reconstruct global and hemispheric temperature for the period 1600-2000 from world-wide glacier length fluctuations. The reconstructions show that global temperature was more or less constant from 1600 until the middle of

  4. The contribution of subsistence to global human cranial variation.

    PubMed

    Noback, Marlijn L; Harvati, Katerina

    2015-03-01

    Diet-related cranial variation in modern humans is well documented on a regional scale, with ample examples of cranial changes related to the agricultural transition. However, the influence of subsistence strategy on global cranial variation is less clear, having been confirmed only for the mandible, and dietary effects beyond agriculture are often neglected. Here we identify global patterns of subsistence-related human cranial shape variation. We analysed a worldwide sample of 15 populations (n = 255) with known subsistence strategies using 3-D landmark datasets designed to capture the shape of different units of the cranium. Results show significant correlations between global cranial shape and diet, especially for temporalis muscle shape and general cranial shape. Importantly, the differences between populations with either a plant- or an animal-based diet are more pronounced than those between agriculturalists and hunter-gatherers, suggesting that the influence of diet as driver of cranial variation is not limited to Holocene transitions to agricultural subsistence. Dental arch shape did not correlate with subsistence pattern, possibly indicating the high plasticity of this region of the face in relation to age, disease and individual use of the dentition. Our results highlight the importance of subsistence strategy as one of the factors underlying the evolution of human geographic cranial variation.

  5. Testing empirical relationships between global sea-level and global temperature in long climate model simulations

    NASA Astrophysics Data System (ADS)

    von Storch, H.; Zorita, E.; Gonzalez-Rouco, F.

    2009-04-01

    Estimations of future global sea-level rise brought about by increasing concentrations of atmospheric greenhouse gases of anthropogenic origin are based on simulations with coarse-resolution global climate models, which imposes some limitations on the skill of future projections because some of the processes that modulate the heat and fresh water flux into may not be adequately represented. To fill this gap, and until more complex climate models are available, some ad-hoc methods have been proposed that link the rise in global average temperature with the global mean sea-level rise. The statistical methods can be calibrated with observations and applied to the future global temperature rise simulated by climate models. This methods can be tested in the virtual reality simulated by global atmosphere.ocean models. Thereby, deficiencies can be identified and improvement suggested. The output of 1000-year long climate model simulation with the coupled atmosphere-ocean model ECHO-G over the past millennium has been used to determine the skill of different predictors to describe the variations of the rate of sea-level change in the simulation. These predictor variables comprise the global mean near-surface temperature, its rate of change with time and the heat-flux into the ocean. It is found that, in the framework of this climate simulation, global mean temperature is not a good predictor for the rate-of-change of sea-level. The correlation between both variables is not stable along the simulations and even its sign changes. A better predictor is the rate-of-change of temperature. Its correlation with the rate-of-change of sea-level is much more stable, it is always positive along the simulation, and there exists a lead-lag relationship between both that can be understood in simple physical terms. The best predictor among those tested is the heat-flux into the ocean. Its correlation is higher and there exists no time lag to the rate-of-change of sea-level, as expected

  6. High temperature and temperature variation undermine future disease susceptibility in a population of the invasive garden ant Lasius neglectus

    NASA Astrophysics Data System (ADS)

    Pamminger, Tobias; Steier, Thomas; Tragust, Simon

    2016-06-01

    Environmental temperature and temperature variation can have strong effects on the outcome of host-parasite interactions. Whilst such effects have been reported for different host systems, long-term consequences of pre-infection temperatures on host susceptibility and immunity remain understudied. Here, we show that experiencing both a biologically relevant increase in temperature and temperature variation undermines future disease susceptibility of the invasive garden ant Lasius neglectus when challenged with a pathogen under a constant temperature regime. In light of the economic and ecological importance of many social insects, our results emphasise the necessity to take the hosts' temperature history into account when studying host-parasite interactions under both natural and laboratory conditions, especially in the face of global change.

  7. High temperature and temperature variation undermine future disease susceptibility in a population of the invasive garden ant Lasius neglectus.

    PubMed

    Pamminger, Tobias; Steier, Thomas; Tragust, Simon

    2016-06-01

    Environmental temperature and temperature variation can have strong effects on the outcome of host-parasite interactions. Whilst such effects have been reported for different host systems, long-term consequences of pre-infection temperatures on host susceptibility and immunity remain understudied. Here, we show that experiencing both a biologically relevant increase in temperature and temperature variation undermines future disease susceptibility of the invasive garden ant Lasius neglectus when challenged with a pathogen under a constant temperature regime. In light of the economic and ecological importance of many social insects, our results emphasise the necessity to take the hosts' temperature history into account when studying host-parasite interactions under both natural and laboratory conditions, especially in the face of global change.

  8. The influence of global sea surface temperature variability on the large-scale land surface temperature

    NASA Astrophysics Data System (ADS)

    Tyrrell, Nicholas L.; Dommenget, Dietmar; Frauen, Claudia; Wales, Scott; Rezny, Mike

    2015-04-01

    In global warming scenarios, global land surface temperatures () warm with greater amplitude than sea surface temperatures (SSTs), leading to a land/sea warming contrast even in equilibrium. Similarly, the interannual variability of is larger than the covariant interannual SST variability, leading to a land/sea contrast in natural variability. This work investigates the land/sea contrast in natural variability based on global observations, coupled general circulation model simulations and idealised atmospheric general circulation model simulations with different SST forcings. The land/sea temperature contrast in interannual variability is found to exist in observations and models to a varying extent in global, tropical and extra-tropical bands. There is agreement between models and observations in the tropics but not the extra-tropics. Causality in the land-sea relationship is explored with modelling experiments forced with prescribed SSTs, where an amplification of the imposed SST variability is seen over land. The amplification of to tropical SST anomalies is due to the enhanced upper level atmospheric warming that corresponds with tropical moist convection over oceans leading to upper level temperature variations that are larger in amplitude than the source SST anomalies. This mechanism is similar to that proposed for explaining the equilibrium global warming land/sea warming contrast. The link of the to the dominant mode of tropical and global interannual climate variability, the El Niño Southern Oscillation (ENSO), is found to be an indirect and delayed connection. ENSO SST variability affects the oceans outside the tropical Pacific, which in turn leads to a further, amplified and delayed response of.

  9. Intraseasonal oscillation in global ocean temperature inferred from Argo

    NASA Astrophysics Data System (ADS)

    Hu, Ruijin; Wei, Meng

    2013-01-01

    The intraseasonal oscillation (ISO; 14-97-day periods) of temperature in the upper 2000 m of the global ocean was studied based on Argo observations from 2003-2008. It is shown that near the surface the ISO existed mainly in a band east of 60°E, between 10°S and 10°N, and the region around the Antarctic Circumpolar Current (ACC). At other levels analyzed, the ISOs also existed in the regions of the Kuroshio, the Gulf Stream, the Indonesian throughflow, the Somalia current, and the subtropical countercurrent (STCC) of the North Pacific. The intraseasonal signals can be seen even at depths of about 2000 m in some regions of the global ocean. The largest amplitude of ISO appeared at the thermocline of the equatorial Pacific, Atlantic and Indian Ocean, with maximum standard deviation (STD) exceeding 1.2°C. The ACC, the Kuroshio, and the Gulf Stream regions all exhibited large STD for all levels analyzed. Especially at 1000 m, the largest STD appeared in the south and southeast of South Africa-a part of the ACC, with a maximum value that reached 0.5°C. The ratios of the intraseasonal temperature variance to the total variance at 1000 m and at the equator indicated that, in a considerable part of the global deep ocean, the ISO was dominant in the variations of temperature, since such a ratio exceeded even 50% there. A case study also confirmed the existence of the ISO in the deep ocean. These results provide useful information for the design of field observations in the global ocean. Analysis and discussion are also given for the mechanism of the ISO.

  10. Atmospheric response to variations in sea surface temperature

    NASA Technical Reports Server (NTRS)

    Spar, J.; Atlas, R.

    1974-01-01

    An extended range prediction experiment was performed with the GISS atmospheric model on a global data to test the sensitivity of the model to sea surface temperature (SST) variation over a two-week forecast period. The use of an initial observed SST field in place of the climatological monthly mean sea temperatures for surface flux calculations in the model was found to have a significant effect on the predicted precipitation over the ocean, with enhanced convection computed over areas where moderately large warm SST anomalies are found. However, there was no detectable positive effect of the SST anomaly field on forecast quality. The influence of the SST anomalies on the daily predicted fields of pressure and geopotential is relatively insignificant up to about one week compared with the growth of prediction error, and is no greater over a two-week period than that resulting from random errors in the initial meteorological state. The 14-day average fields of sea level pressure and 500-mb height predicted by the model, appear to be similarly insensitive to anomalies of sea surface temperature.

  11. Global Precipitation: Means, Variations and Trends During the Satellite Era (1979-2014)

    NASA Astrophysics Data System (ADS)

    Adler, Robert F.; Gu, Guojun; Sapiano, Matthew; Wang, Jian-Jian; Huffman, George J.

    2017-07-01

    Global precipitation variations over the satellite era are reviewed using the Global Precipitation Climatology Project (GPCP) monthly, globally complete analyses, which integrate satellite and surface gauge information. Mean planetary values are examined and compared, over ocean, with information from recent satellite programs and related estimates, with generally positive agreements, but with some indication of small underestimates for GPCP over the global ocean. Variations during the satellite era in global precipitation are tied to ENSO events, with small increases during El Ninos, and very noticeable decreases after major volcanic eruptions. No overall significant trend is noted in the global precipitation mean value, unlike that for surface temperature and atmospheric water vapor. However, there is a pattern of positive and negative trends across the planet with increases over tropical oceans and decreases over some middle latitude regions. These observed patterns are a result of a combination of inter-decadal variations and the effect of the global warming during the period. The results reviewed here indicate the value of such analyses as GPCP and the possible improvement in the information as the record lengthens and as new, more sophisticated and more accurate observations are included.

  12. Air temperature variation across the seed cotton dryer mixpoint

    USDA-ARS?s Scientific Manuscript database

    Eighteen tests were conducted in six gins in the fall of 2008 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the...

  13. Development of a Pressure Sensitive Paint System with Correction for Temperature Variation

    NASA Technical Reports Server (NTRS)

    Simmons, Kantis A.

    1995-01-01

    Pressure Sensitive Paint (PSP) is known to provide a global image of pressure over a model surface. However, improvements in its accuracy and reliability are needed. Several factors contribute to the inaccuracy of PSP. One major factor is that luminescence is temperature dependent. To correct the luminescence of the pressure sensing component for changes in temperature, a temperature sensitive luminophore incorporated in the paint allows the user to measure both pressure and temperature simultaneously on the surface of a model. Magnesium Octaethylporphine (MgOEP) was used as a temperature sensing luminophore, with the pressure sensing luminophore, Platinum Octaethylporphine (PtOEP), to correct for temperature variations in model surface pressure measurements.

  14. Global Oxygen Atom and Temperature (GOAT) Mapping

    NASA Astrophysics Data System (ADS)

    Slanger, T. G.; Huestis, D. L.

    2001-12-01

    We suggest that global maps of temperature and oxygen-atom density, in the 120-250 km altitude range, can be inferred from space-based observations of the band profiles of O2 Atmospheric band emissions in the 755-785 nm spectral region. Unpublished data from the GLO [1] and MSX [2] programs show that the O2(b-X) 0-0 and 1-1 bands are observable up to 250 km. The width of the rotational band profiles and the relative intensity of O2(b-X) 1-1 emission increase towards higher altitudes. Local kinetic temperatures can be derived from the rotational band profiles, and oxygen atom densities can be derived from the ratio of the O2(b-X) 0-0 and 1-1 intensities. No observational calibration is required, other than spectral response and tangent altitude. For long-term global measurements of [O] and T, the International Space Station would provide an excellent platform. In the thermosphere, O2(b,v=0) and O2(b,v=1) are produced principally by energy transfer from O(1D) to O2. The O(1D) comes from photodissociation of O2, electron impact on O, and dissociative recombination of O2+, with the latter process dominant in the nightglow. At high altitudes both O2(b,v=0) and O2(b,v=1) radiate efficiently, in spite of the long 12-sec radiative lifetime, and their approximately equal emission intensities reflect the known equal production yields. The GLO data show that the relative intensity of O2(b,v=1) emission begins to drop as the altitude is reduced below 200 km. The known rates of quenching in collisions with O2 and N2 are far too small to be effective at such high altitudes, while O2(b,v=0) is unquenched at all altitudes above 100 km. We conclude that the principal quencher of O2(b,v=1) is the ground state of atomic oxygen, O(3P), and infer a rate coefficient of approximately 1x10-11 cm3 s-1. After this rate coefficient has been measured in the laboratory, we will be able to use the ratio of the O2(b-X) 0-0 and 1-1 band intensities to determine the absolute oxygen atom altitude

  15. Global variations in the geoid/topography admittance of venus.

    PubMed

    Simons, M; Hager, B H; Solomon, S C

    1994-05-06

    Global representations of geoid height and topography are used to map variations in the geoid/topography ratio (admittance) of Venus. The admittance values are permissive of two mutually exclusive models for convection-driven topography. In the first, compressive highland plateaus are expressions of present mantle downwelling, broad volcanic rises are expressions of mantle upwelling, and lowlands overlie regions with no substantial vertical motion in the mantle. In the second, compressive highland plateaus are remnants of an earlier regime of high crustal strain, and most other long-wavelength topographic variations arise from normal convective tractions at the base of the lithosphere.

  16. Global and Regional Diurnal Variations of Organized Convection.

    NASA Astrophysics Data System (ADS)

    Tsakraklides, Giorgos; Evans, Jenni L.

    2003-05-01

    An automated objective classification procedure, the Convection Classification and Automated Tracking System (CCATS), is used to analyze the mean life cycles of organized convection in the global Tropics and midlatitudes (40°N-40°S). Five years (1989-93) of infrared satellite imagery are examined for the Pacific and Atlantic basins and one year (April 1988-March 1989) is studied for the Indian basin.Two main classes of organized convection (lifetime of 6 h or more) are tracked: MCT and CCC. MCT represent a combined dataset of tropical cyclones and mesoscale convective complexes (MCC). Convective cloud clusters (CCC) meet the same cold cloud-top temperature, time, and size criteria used to distinguish MCC, but fail to sustain the same high degree of symmetry for at least 6 h. That is, CCC represent more elongated systems, such as squall lines. The frequency of CCC exceeds that of MCT by a factor of 30 over both land and sea.MCT and CCC are each stratified to into 12 continental and oceanic regions and the diurnal variation of system characteristics in each geographic region are studied, leading to composite life cycle descriptions for each region. Oceanic CCC formed overnight and the shorter-lived, land-based CCC formed in the afternoon; apart from this time offset, oceanic and land-based CCC were found to have very similar life cycle evolution patterns.Continental MCT exhibit a rapid size expansion early; this is not part of the oceanic system life cycle. Apart from this growth spurt, the evolution of land and ocean MCT follows the same pattern of CCC with early symmetry, then size expansion until just before termination. Land-based MCT are longer lived and more symmetric than oceanic MCT.

  17. Microchannel plate modal gain variations with temperature

    NASA Technical Reports Server (NTRS)

    Slater, David C.; Timothy, J. G.

    1993-01-01

    Measurements of the modal gain of two high-gain curved-channel microchannel plates (MCPs) at various operating temperatures are presented. Both MCPs were fabricated from the Long Life glass with 12-micron diam channels on 15-micron centers. The modal gain was found to decrease with increasing temperature at a rate of -0.1 percent C. This reduction of gain with temperature is attributed primarily to an axial temperature gradient along each MCP channel creating a nonuniform electric field within the channel that lowers the effective output gain. A lowering of the secondary electron yield resulting from increased phonon scattering of secondary electrons released within the walls of the MCP channels was assessed, but was found to have a negligible contribution to the drop in gain with temperature.

  18. Global Average Brightness Temperature for April 2003

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site] Figure 1

    This image shows average temperatures in April, 2003, observed by AIRS at an infrared wavelength that senses either the Earth's surface or any intervening cloud. Similar to a photograph of the planet taken with the camera shutter held open for a month, stationary features are captured while those obscured by moving clouds are blurred. Many continental features stand out boldly, such as our planet's vast deserts, and India, now at the end of its long, clear dry season. Also obvious are the high, cold Tibetan plateau to the north of India, and the mountains of North America. The band of yellow encircling the planet's equator is the Intertropical Convergence Zone (ITCZ), a region of persistent thunderstorms and associated high, cold clouds. The ITCZ merges with the monsoon systems of Africa and South America. Higher latitudes are increasingly obscured by clouds, though some features like the Great Lakes, the British Isles and Korea are apparent. The highest latitudes of Europe and Eurasia are completely obscured by clouds, while Antarctica stands out cold and clear at the bottom of the image.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  19. Global Biomass Variation and its Geodynamic Effects, 1982-1998

    NASA Technical Reports Server (NTRS)

    Rodell, M.; Chao, B. F.; Au, A. Y.; Kimball, J. S.; McDonald, K. C.

    2005-01-01

    Redistribution of mass near Earth's surface alters its rotation, gravity field, and geocenter location. Advanced techniques for measuring these geodetic variations now exist, but the ability to attribute the observed modes to individual Earth system processes has been hampered by a shortage of reliable global data on such processes, especially hydrospheric processes. To address one aspect of this deficiency, 17 yrs of monthly, global maps of vegetation biomass were produced by applying field-based relationships to satellite-derived vegetation type and leaf area index. The seasonal variability of biomass was estimated to be as large as 5 kg m(exp -2). Of this amount, approximately 4 kg m(exp -2) is due to vegetation water storage variations. The time series of maps was used to compute geodetic anomalies, which were then compared with existing geodetic observations as well as the estimated measurement sensitivity of the Gravity Recovery and Climate Experiment (GRACE). For gravity, the seasonal amplitude of biomass variations may be just within GRACE'S limits of detectability, but it is still an order of magnitude smaller than current observation uncertainty using the satellite-laser-ranging technique. The contribution of total biomass variations to seasonal polar motion amplitude is detectable in today's measurement, but it is obscured by contributions from various other sources, some of which are two orders of magnitude larger. The influence on the length of day is below current limits of detectability. Although the nonseasonal geodynamic signals show clear interannual variability, they are too small to be detected.

  20. Global Biomass Variation and its Geodynamic Effects, 1982-1998

    NASA Technical Reports Server (NTRS)

    Rodell, M.; Chao, B. F.; Au, A. Y.; Kimball, J. S.; McDonald, K. C.

    2005-01-01

    Redistribution of mass near Earth's surface alters its rotation, gravity field, and geocenter location. Advanced techniques for measuring these geodetic variations now exist, but the ability to attribute the observed modes to individual Earth system processes has been hampered by a shortage of reliable global data on such processes, especially hydrospheric processes. To address one aspect of this deficiency, 17 yrs of monthly, global maps of vegetation biomass were produced by applying field-based relationships to satellite-derived vegetation type and leaf area index. The seasonal variability of biomass was estimated to be as large as 5 kg m(exp -2). Of this amount, approximately 4 kg m(exp -2) is due to vegetation water storage variations. The time series of maps was used to compute geodetic anomalies, which were then compared with existing geodetic observations as well as the estimated measurement sensitivity of the Gravity Recovery and Climate Experiment (GRACE). For gravity, the seasonal amplitude of biomass variations may be just within GRACE'S limits of detectability, but it is still an order of magnitude smaller than current observation uncertainty using the satellite-laser-ranging technique. The contribution of total biomass variations to seasonal polar motion amplitude is detectable in today's measurement, but it is obscured by contributions from various other sources, some of which are two orders of magnitude larger. The influence on the length of day is below current limits of detectability. Although the nonseasonal geodynamic signals show clear interannual variability, they are too small to be detected.

  1. Regionalized temperature variations in the upper 400 km of the Earth's mantle

    NASA Astrophysics Data System (ADS)

    Tralli, David M.; Ita, Joel J.

    Tectonically regionalized variations in the temperature of the upper 400 km of the Earth's mantle are estimated from analysis of global seismic travel-time data cataloged by the International Seismological Centre (ISC). Seismic parameter profiles are determined from estimates of P and S velocities obtained by tau inversion. Summary phase diagrams for the olivine and pyroxene-garnet subsystems are constructed in conjunction with a thermodynamic potential formulation that allows self-consistent determination of density, bulk modulus and adiabats throughout the pressure and temperature regimes of the mantle. Perturbations in estimated seismic parameters are expressed in terms of variations in temperature using the model temperature derivatives of the bulk modulus and density at a given temperature and pressure. Confidence bounds on the velocity estimates are used to place corresponding bounds on the constructed seismic parameters. A simple differential relationship is solved iteratively to obtain a temperature variation for a given variation in seismic parameter. This approach allows the estimation of a range of seismically determined temperature variations by employing a given compositional model. Results indicate that whereas the P and S velocity variations in the upper mantle are consistent with the tectonic regionalization, variations in V p/V s ratios are irregular. This leads to unstable estimates of the seismic parameters and thus estimates of mean temperature anomalies, typically within 600°C of the weighted mean, that are inconsistent with the regionalized seismic data. A comparison of two compositional models is used to show the trade-off with estimated temperature variations. A refined regionalization and analysis of a larger ISC data set are suggested to stabilize the S velocity inversion, reduce statistical uncertainties on the seismic parameters, and thus improve constraints on estimated temperature variations.

  2. Variation in Plant Traits Explains Global Biogeographic Variation in the Abundance of Major Forest Functional Types

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2015-12-01

    Contrasting leaf types (needle vs. broadleaf) with different lifespans (annual vs. perennial) represent different adaptive strategies of plants under different environmental conditions. Previous studies explained adaptive advantages of different strategies using empirical models but cannot adequately explain the co-dominance of multiple plant functional types (PFTs) as observed in many parts of the world. Here we used a process-based model to explore whether observed inter- and intra-PFT variation in key plant traits can explain global biogeographic variation in co-dominance of major forest functional types. Using a parameter screening method, we identified the four most important plant traits for simulating annual net primary production (NPP) using the Australian Community Atmosphere-Biosphere-Land Exchange model (CABLE). Using ensemble CABLE simulations, we estimated the fraction of global land cover attributed to each PFT by comparing the simulated NPP for all three PFTs at each land point, globally. Our results were consistent with land area cover fractions of major forest types estimated from remote sensing data products; i.e., evergreen needle-leaf forests dominate in boreal regions, evergreen broadleaf forests dominate in tropical regions, and deciduous broadleaf forests are distributed widely across a broad range of environmental conditions. More importantly our approach successfully explained a paradox that has puzzled ecologists for over a century: why evergreen leaf types dominate in both boreal and tropical regions. We conclude that variation in and co-variation between key plant traits can explain significant fractions of global biogeographic variation of three major forest types, and should be taken into account when simulating global vegetation dynamics.

  3. Connection between variations of the atmosphere temperature profile and variations of the meson component intensity

    NASA Technical Reports Server (NTRS)

    Blokh, Y. L.; Rogovaya, S. I.

    1985-01-01

    The influence of temperature effects on intensity variations of the cosmic ray meson component were studied. The connection between the temperature variation delta T and the intensity variation delta I was established by using the temperature coefficient density technique. To realize how many devices are needed on the Earth for predicting the temperature variation of the atmosphere profile with a reasonable accuracy, IO isobaric levels and IO were calculated. The set of initial elements of the cosmic ray mesons are varied and it is shown that the matrix of the coefficients B sub ij is rather sensitive to their choice. It is found that if for the calculations of the atmospheric temperature variations the model is used, the number of meson components, essentially exceeding 3, should be considered.

  4. Comparative terrestrial planet thermospheres 3. Solar cycle variation of global structure and winds at solstices

    NASA Astrophysics Data System (ADS)

    Bougher, S. W.; Engel, S.; Roble, R. G.; Foster, B.

    2000-07-01

    The comparison of planetary upper atmospheres using global databases has entered a new era with the advent of recent aerobraking measurements of the Mars thermosphere [e.g., Keating, et al., 1998a]. The present maturity of available modeling capabilities also permits us to contrast the Earth and Mars thermosphere structures, winds, and controlling processes using global three-dimensional models [e.g., Bougher et al., 1999b]. This present effort focuses upon the comparison of the combined seasonal-solar cycle responses of the thermospheres of Earth and Mars using the National Center for Atmospheric Research (NCAR) Thermospheric General Circulation Model (TGCM) utility to address the coupled energetics, dynamics, and neutral-ion composition above ~100 km. Extreme thermospheric conditions are expected at solstices, thereby revealing the changing importance of fundamental physical processes controlling the Earth and Mars thermospheric structures and winds. Seasonal-solar cycle extremes in Mars exobase temperatures are calculated to range from 200 to 380 K, giving rise to maximum horizontal winds of nearly 215 to 400 m/s. Corresponding extremes in Earth exobase temperatures are 700 to 1600 K, with rather small variations in global winds. The orbital eccentricities of Earth and Mars are also shown to drive substantial variations in their thermospheric temperatures. For Mars, dayside exobase temperatures vary by ~60 K (18%) from aphelion to perihelion during solar maximum conditions. Such large temperature variations strongly impact thermospheric densities and global winds. The corresponding Earth dayside temperatures also vary by 60-80 K between solstices. However, the percent temperature variation (5%) over the Earth's orbit and its overall impact on the thermospheric structure and winds are much smaller. Auroral activity may in fact obscure these orbital variations. Changing dust conditions throughout the Martian year modulate the aerosol heating of its lower

  5. Effect of Periodic Surface Air Temperature Variations on Subsurface Thermal Structure with Vertical Fluid flow

    NASA Astrophysics Data System (ADS)

    D, R. V.; Ravi, M.; Srivastava, K.

    2016-12-01

    The influence of climate change on near subsurface temperatures is an important research topic for global change impact assessment at the regional scale. The varying temperature of the air over the surface in long term will disturb subsurface thermal structure. Groundwater flow is another important process which perturbs the thermal distribution into the subsurface. To investigate the effect of periodic air temperature on nonisothermal subsurface, one dimensional transient heat conduction-advection equation is solved numerically using finite element method. Thermal response of subsurface for periodic variations in surface air temperature (SAT) with robin type boundary condition on the surface with vertical ground water flow are calculated and the amplitude attenuation of propagation of surface temperature information in the subsurface for different scenarios of advection and convective coefficient are discussed briefly. The results show the coupled response of trigonometric variation in air temperature with surface temperatures along with ground water velocity has significant implications for the effects of climate change.

  6. Global surface temperature change analysis based on MODIS data in recent twelve years

    NASA Astrophysics Data System (ADS)

    Mao, K. B.; Ma, Y.; Tan, X. L.; Shen, X. Y.; Liu, G.; Li, Z. L.; Chen, J. M.; Xia, L.

    2017-01-01

    Global surface temperature change is one of the most important aspects in global climate change research. In this study, in order to overcome shortcomings of traditional observation methods in meteorology, a new method is proposed to calculate global mean surface temperature based on remote sensing data. We found that (1) the global mean surface temperature was close to 14.35 °C from 2001 to 2012, and the warmest and coldest surface temperatures of the global in the recent twelve years occurred in 2005 and 2008, respectively; (2) the warmest and coldest surface temperatures on the global land surface occurred in 2005 and 2001, respectively, and on the global ocean surface in 2010 and 2008, respectively; and (3) in recent twelve years, although most regions (especially the Southern Hemisphere) are warming, global warming is yet controversial because it is cooling in the central and eastern regions of Pacific Ocean, northern regions of the Atlantic Ocean, northern regions of China, Mongolia, southern regions of Russia, western regions of Canada and America, the eastern and northern regions of Australia, and the southern tip of Africa. The analysis of daily and seasonal temperature change indicates that the temperature change is mainly caused by the variation of orbit of celestial body. A big data model based on orbit position and gravitational-magmatic change of celestial body with the solar or the galactic system should be built and taken into account for climate and ecosystems change at a large spatial-temporal scale.

  7. Tsunami speed variations in density-stratified compressible global oceans

    NASA Astrophysics Data System (ADS)

    Watada, Shingo

    2013-08-01

    Tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth-variable sound speeds and density gradients. For a 4 km deep ocean, the total tsunami speed reduction is 0.44% compared with incompressible homogeneous seawater; two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression. Tsunami speeds are computed for global ocean density and sound speed profiles, and characteristic structures are discussed. Tsunami speed reductions are proportional to ocean depth with small variations, except in warm Mediterranean seas. The impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of transoceanic tsunamis.

  8. Geophysical and geochemical evidence for deep temperature variations beneath mid-ocean ridges.

    PubMed

    Dalton, Colleen A; Langmuir, Charles H; Gale, Allison

    2014-04-04

    The temperature and composition of Earth's mantle control fundamental planetary properties, including the vigor of mantle convection and the depths of the ocean basins. Seismic wave velocities, ocean ridge depths, and the composition of mid-ocean ridge basalts can all be used to determine variations in mantle temperature and composition, yet are typically considered in isolation. We show that correlations among these three data sets are consistent with 250°C variation extending to depths >400 kilometers and are inconsistent with variations in mantle composition at constant temperature. Anomalously hot ridge segments are located near hot spots, confirming a deep mantle-plume origin for hot spot volcanism. Chemical heterogeneity may contribute to scatter about the global trend. The coherent temperature signal provides a thermal calibration scale for interpreting seismic velocities located distant from ridges.

  9. Modeling seasonal surface temperature variations in secondary tropical dry forests

    NASA Astrophysics Data System (ADS)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  10. The Variation of Electrochemical Cell Potentials with Temperature

    ERIC Educational Resources Information Center

    Peckham, Gavin D.; McNaught, Ian J.

    2011-01-01

    Electrochemical cell potentials have no simple relationship with temperature but depend on the interplay between the sign and magnitude of the isothermal temperature coefficient, dE[degrees]/dT, and on the magnitude of the reaction quotient, Q. The variations in possible responses of standard and non-standard cell potentials to changes in the…

  11. The Variation of Electrochemical Cell Potentials with Temperature

    ERIC Educational Resources Information Center

    Peckham, Gavin D.; McNaught, Ian J.

    2011-01-01

    Electrochemical cell potentials have no simple relationship with temperature but depend on the interplay between the sign and magnitude of the isothermal temperature coefficient, dE[degrees]/dT, and on the magnitude of the reaction quotient, Q. The variations in possible responses of standard and non-standard cell potentials to changes in the…

  12. Temperature Variations Recorded During Interinstitutional Air Shipments of Laboratory Mice

    PubMed Central

    Syversen, Eric; Pineda, Fernando J; Watson, Julie

    2008-01-01

    Despite extensive guidelines and regulations that govern most aspects of rodent shipping, few data are available on the physical environment experienced by rodents during shipment. To document the thermal environment experienced by mice during air shipments, we recorded temperatures at 1-min intervals throughout 103 routine interinstitutional shipments originating at our institution. We found that 49.5% of shipments were exposed to high temperatures (greater than 29.4 °C), 14.6% to low temperatures (less than 7.2 °C), and 61% to temperature variations of 11 °C or more. International shipments were more likely than domestic shipments to experience temperature extremes and large variations in temperature. Freight forwarders using passenger airlines rather than their own airplanes were more likely to have shipments that experienced temperature extremes or variations. Temperature variations were most common during stopovers. Some airlines were more likely than others to experience inflight temperature extremes or swings. Most domestic shipments lasted at least 24 h, whereas international shipments lasted 48 to 72 h. Despite exposure to high and low temperatures, animals in all but 1 shipment arrived alive. We suggest that simple measures, such as shipping at night during hot weather, provision of nesting material in shipping crates, and specifying aircraft cargo-hold temperatures that are suitable for rodents, could reduce temperature-induced stress. Measures such as additional training for airport ground crews, as previously recommended by the American Veterinary Medical Association, could further reduce exposure of rodents to extreme ambient temperatures during airport stopovers. PMID:18210996

  13. [Responses of Chinese pine tree ring in Shenyang suburb (Fu Mausoleum) to global temperature fluctuation].

    PubMed

    Chen, Zhen-Ju; He, Xing-Yuan; Chen, Wei; Sun, Yu; Zhang, Chun-Tao; Fu, Yin-Dong; Tian, Wei; Liu, Tie-Hong

    2007-09-01

    In this paper, the correlations between the variations of Chinese pine (Pinus tabulaeformis Carr.) tree ring width in Shenyang suburb (Fu Mausoleum) and the local temperature variables, Global Surface Air Temperature Anomaly (GSATA) from 1880 to 2004, Global Land-Ocean Temperature (GLOTI) from 1880 to 2004 and North Hemisphere Temperature Anomaly (NHTA) from 1880 to 2004 were studied. Some close correlations were detected, and the local temperature variables, GSATA, GLOTI and NHTA had some similar influences on the Chinese pine tree ring width. The air temperature in last winter (December and January) and in spring (April and May) affected the growth of Chinese pine significantly (P < 0.05). There existed a 3-8-year periodicity of the variation of Chinese pine tree ring width and the GSATA, GLOTI and NHTA, and the 19.3-year and 23.2-year quasi-periodicity of the variation of Chinese pine tree ring width corresponded with the 20.8-year quasi-periodicity of GSATA, GLOTI and NHTA. This study suggested that the Chinese pine tree ring width in Shenyang Fu Mausoleum had positive correlations with global-scale temperature fluctuation, and the temperature increase in the past had a positive effect on the Chinese pine growth.

  14. Rising temperatures reduce global wheat production

    USDA-ARS?s Scientific Manuscript database

    Crop models are essential to assess the threat of climate change for food production but have not been systematically tested against temperature experiments, despite demonstrated uncertainty in temperature response. Herein, we compare 30 different wheat crop models against field experiments in which...

  15. Global relationships among the earth's radiation budget, cloudiness, volcanic aerosols, and surface temperature

    NASA Technical Reports Server (NTRS)

    Ardanuy, Philip E.; Kyle, H. L.; Hoyt, Douglas

    1992-01-01

    Global relationships among the earth's radiation budget, cloudiness, solar constant, volcanic aerosols, and surface temperature are analyzed using data obtained by the Nimbus-7 spacecraft. It was found that these parameters were interrelated on interannual time scales, demonstrating that the interannual variability in the earth's climate (i.e., radiation budget) is detectable and observable by current spaceborne instruments. The degree of global interannual variation is on the order of tenths of percent.

  16. Global relationships among the earth's radiation budget, cloudiness, volcanic aerosols, and surface temperature

    SciTech Connect

    Ardanuy, P.E.; Kyle, H.L.; Hoyt, D. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1992-10-01

    Global relationships among the earth's radiation budget, cloudiness, solar constant, volcanic aerosols, and surface temperature are analyzed using data obtained by the Nimbus-7 spacecraft. It was found that these parameters were interrelated on interannual time scales, demonstrating that the interannual variability in the earth's climate (i.e., radiation budget) is detectable and observable by current spaceborne instruments. The degree of global interannual variation is on the order of tenths of percent. 41 refs.

  17. Global relationships among the earth's radiation budget, cloudiness, volcanic aerosols, and surface temperature

    NASA Technical Reports Server (NTRS)

    Ardanuy, Philip E.; Kyle, H. L.; Hoyt, Douglas

    1992-01-01

    Global relationships among the earth's radiation budget, cloudiness, solar constant, volcanic aerosols, and surface temperature are analyzed using data obtained by the Nimbus-7 spacecraft. It was found that these parameters were interrelated on interannual time scales, demonstrating that the interannual variability in the earth's climate (i.e., radiation budget) is detectable and observable by current spaceborne instruments. The degree of global interannual variation is on the order of tenths of percent.

  18. Tsunami Speed Variations in Density-stratified Compressible Global Oceans

    NASA Astrophysics Data System (ADS)

    Watada, S.

    2013-12-01

    Recent tsunami observations in the deep ocean have accumulated unequivocal evidence that tsunami traveltime delays compared with the linear long-wave tsunami simulations occur during tsunami propagation in the deep ocean. The delay is up to 2% of the tsunami traveltime. Watada et al. [2013] investigated the cause of the delay using the normal mode theory of tsunamis and attributed the delay to the compressibility of seawater, the elasticity of the solid earth, and the gravitational potential change associated with mass motion during the passage of tsunamis. Tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth-variable sound speeds and density gradients. For a 4-km deep ocean, the total tsunami speed reduction is 0.45% compared with incompressible homogeneous seawater; two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression. Tsunami speeds are computed for global ocean density and sound speed profiles and characteristic structures are discussed. Tsunami speed reductions are proportional to ocean depth with small variations, except for in warm Mediterranean seas. The impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of trans-oceanic tsunamis. Data locations where a vertical ocean profile deeper than 2500 m is available in World Ocean Atlas 2009. The dark gray area indicates the Pacific Ocean defined in WOA09. a) Tsunami speed variations. Red, gray and black bars represent global, Pacific, and Mediterranean Sea, respectively. b) Regression lines of the tsunami velocity reduction for all oceans. c)Vertical ocean profiles at grid points indicated by the stars in Figure 1.

  19. Global variation and uniformity of eggshell thickness for chicken eggs.

    PubMed

    Sun, C J; Chen, S R; Xu, G Y; Liu, X M; Yang, N

    2012-10-01

    Damaged eggshells result in losses of eggs. Numerous efforts have been carried out to improve eggshell quality, which may lead to increased eggshell thickness. The conventional way of enhancing eggshell strength with thicker eggshell on average may be replaced by a new strategy to improve eggshell uniformity without increasing eggshell thickness. To achieve this, it is necessary to investigate global variation of eggshell thickness. In this study, we used 100 fresh eggs from 52-wk-old layers of a commercial brown-egg variety. To determine the global variation of eggshell thickness, 42 points for each egg along both longitudinal and latitudinal axes were selected to measure thickness using an eggshell thickness gauge. The eggshell thickness from blunt to sharp end varied significantly (P < 0.05). The area surrounding the blunt end was the thinnest (0.341 ± 0.025 mm), whereas the area surrounding the sharp end was the thickest (0.367 ± 0.023 mm). It was found that the thickness of the sharp end was the closest to the average thickness of the whole eggshell and could be considered as a valid measurement of eggshell thickness. A new parameter, eggshell thickness uniformity, was defined as the reciprocal of the coefficient of variation (1/CV) of eggshell thickness from 42 points of each egg and can be used to evaluate the eggshell quality. Eggshell thickness uniformity was positively correlated with breaking strength (r = 0.341; P < 0.01), suggesting that the parameter may be used as a potential selection criterion in breeding program to improve eggshell quality without increasing eggshell thickness.

  20. Hydroclimatic Controls over Global Variations in Phenology and Carbon Flux

    NASA Technical Reports Server (NTRS)

    Koster, Randal; Walker, G.; Thornton, Patti; Collatz, G. J.

    2012-01-01

    The connection between phenological and hydroclimatological variations are quantified through joint analyses of global NDVI, LAI, and precipitation datasets. The global distributions of both NDVI and LAI in the warm season are strongly controlled by three quantities: mean annual precipitation, the standard deviation of annual precipitation, and Budyko's index of dryness. Upon demonstrating that these same basic (if biased) relationships are produced by a dynamic vegetation model (the dynamic vegetation and carbon storage components of the NCAR Community Land Model version 4 combined with the water and energy balance framework of the Catchment Land Surface Model of the NASA Global Modeling and Assimilation Office), we use the model to perform a sensitivity study focusing on how phenology and carbon flux might respond to climatic change. The offline (decoupled from the atmosphere) simulations show us, for example, where on the globe a given small increment in precipitation mean or variability would have the greatest impact on carbon uptake. The analysis framework allows us in addition to quantify the degree to which climatic biases in a free-running GCM are manifested as biases in simulated phenology.

  1. Environmental variation and population responses to global change.

    PubMed

    Lawson, Callum R; Vindenes, Yngvild; Bailey, Liam; van de Pol, Martijn

    2015-07-01

    Species' responses to environmental changes such as global warming are affected not only by trends in mean conditions, but also by natural and human-induced environmental fluctuations. Methods are needed to predict how such environmental variation affects ecological and evolutionary processes, in order to design effective strategies to conserve biodiversity under global change. Here, we review recent theoretical and empirical studies to assess: (1) how populations respond to changes in environmental variance, and (2) how environmental variance affects population responses to changes in mean conditions. Contrary to frequent claims, empirical studies show that increases in environmental variance can increase as well as decrease long-term population growth rates. Moreover, environmental variance can alter and even reverse the effects of changes in the mean environment, such that even if environmental variance remains constant, omitting it from population models compromises their ability to predict species' responses to changes in mean conditions. Drawing on theory relating these effects of environmental variance to the curvatures of population growth responses to the environment, we outline how species' traits such as phylogenetic history and body mass could be used to predict their responses to global change under future environmental variability. © 2015 John Wiley & Sons Ltd/CNRS.

  2. Active structural vibration control: Robust to temperature variations

    NASA Astrophysics Data System (ADS)

    Gupta, Vivek; Sharma, Manu; Thakur, Nagesh

    2012-11-01

    d-form augmented piezoelectric constitutive equations which take into account temperature dependence of piezoelectric strain coefficient (d31) and permittivity (∈33), are converted into e-form. Using e-form constitutive equations, a finite element model of a smart two dimensional plate instrumented with piezoelectric patches is derived. Equations of motion are derived using Hamilton's variational principle. Coupled equations of motion are uncoupled using modal analysis. Modal state vectors are estimated using the Kalman observer. The first mode of smart cantilevered plate is actively controlled using negative first modal velocity feedback at various temperatures. Total control effort required to do so is calculated using the electro-mechanical impedance method. The temperature dependence of sensor voltage, control voltage, control effort and Kalman observer equations is shown analytically. Simulation results are presented using MATLAB. Variations in (i) peak sensor voltage, (ii) actual and estimated first modal velocities, (iii) peak control voltage, (iv) total control effort and (v) settling time with respect to temperature are presented. Active vibration control performance is not maintained at temperature away from reference temperature when the temperature dependence of piezoelectric stress coefficient ‘e31' and permittivity ‘∈33' is not included in piezoelectric constitutive equations. Active control of vibrations becomes robust to temperature variations when the temperature dependence of ‘e31' and ‘∈33' is included in piezoelectric constitutive equations.

  3. Global near-surface temperature estimation using statistical reconstruction techniques

    NASA Astrophysics Data System (ADS)

    Morice, C. P.; Rayner, N. A.; Kennedy, J.

    2015-12-01

    Incomplete and non-uniform observational coverage of the globe is a prominent source of uncertainty in instrumental records of global near-surface temperature change. In this study the capabilities of a range of statistical analysis methods are assessed in producing improved estimates of global near-surface temperature change since the mid 19th century for observational coverage in the HadCRUT4 data set. Methods used include those that interpolate according to local correlation structure (kriging) and reduced space methods that learn large-scale temperature patterns. The performance of each method in estimating regional and global temperature changes has been benchmarked in application to a subset of CMIP5 simulations. Model fields are sub-sampled and simulated observational errors added to emulate observational data, permitting assessment of temperature field reconstruction algorithms in controlled tests in which globally complete temperature fields are known. The reconstruction methods have also been applied to the HadCRUT4 data set, yielding a range of estimates of global near-surface temperature change since the mid 19th century. Results show relatively increased warming in the global average over the 21st century owing to reconstruction of temperatures in high northern latitudes, supporting the findings of Cowtan & Way (2014) and Karl et al. (2015). While there is broad agreement between estimates of global and hemispheric changes throughout much of the 20th and 21st century, agreement is reduced in the 19th and early 20th century. This finding is supported by the climate model trials that highlight uncertainty in reconstructing data sparse regions, most notably in the Southern Hemisphere in the 19th century. These results underline the importance of continued data rescue activities, such as those of the International Surface Temperature Initiative and ACRE. The results of this study will form an addition to the HadCRUT4 global near-surface temperature data

  4. Temperature variation makes ectotherms more sensitive to climate change.

    PubMed

    Paaijmans, Krijn P; Heinig, Rebecca L; Seliga, Rebecca A; Blanford, Justine I; Blanford, Simon; Murdock, Courtney C; Thomas, Matthew B

    2013-08-01

    Ectotherms are considered to be particularly vulnerable to climate warming. Descriptions of habitat temperatures and predicted changes in climate usually consider mean monthly, seasonal or annual conditions. Ectotherms, however, do not simply experience mean conditions, but are exposed to daily fluctuations in habitat temperatures. Here, we highlight how temperature fluctuation can generate 'realized' thermal reaction (fitness) norms that differ from the 'fundamental' norms derived under standard constant temperatures. Using a mosquito as a model organism, we find that temperature fluctuation reduces rate processes such as development under warm conditions, increases processes under cool conditions, and reduces both the optimum and the critical maximum temperature. Generalizing these effects for a range of terrestrial insects reveals that prevailing daily fluctuations in temperature should alter the sensitivity of species to climate warming by reducing 'thermal safety margins'. Such effects of daily temperature dynamics have generally been ignored in the climate change literature. © 2013 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

  5. Computation of photovoltaic parameters under lunar temperature variation

    NASA Technical Reports Server (NTRS)

    Dhere, Neelkanth G.; Santiago, James V.

    1993-01-01

    Photovoltaic (PV) arrays with regenerative-fuel-cell energy storage is a prime, power-system candidate for lunar photo-power. The PV module performance decreases at higher temperatures. Surface temperature variations of the moon are extreme, the maximum (noon) temperature being 384 K. The present work utilizes detailed computations of photovoltaic parameters with computer program developed earlier for the computation of optimum bandgaps of single- and two-junction solar cells at different temperatures, and calculates the power output of single and two-junction solar modules under different configurations which constitutes an improvement over the assumption of a linear variation of efficiency with temperature. The program also calculates the necessary PV-array size to satisfy stipulated levels of day- and night-time power consumption.

  6. Influence of lunar phase on daily global temperatures

    SciTech Connect

    Balling, R.C. Jr.; Cerveny, R.S.

    1995-03-10

    A newly available data set of daily satellite-derived, lower-tropospheric global temperature anomalies provides an opportunity to assess the influence of lunar phase on planetary temperature. These results reveal a statistically significant 0.02 K modulation between new moon and full moon, with the warmest daily global temperatures over a synodic month coincident with the occurrence of the full moon. Spectral analysis of the daily temperature record confirms the presence of a periodicity that matches the lunar synodic (29-53-day) cycle. The precision of the satellite-based daily temperature record allows verification that the moon exerts a discernible influence on the short-term, global temperature record. 25 refs., 2 figs.

  7. Evolution of global temperature over the past two million years

    NASA Astrophysics Data System (ADS)

    Snyder, Carolyn W.

    2016-10-01

    Reconstructions of Earth’s past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today’s greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.

  8. Evolution of global temperature over the past two million years.

    PubMed

    Snyder, Carolyn W

    2016-10-13

    Reconstructions of Earth's past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today's greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.

  9. Partitioning Variation of Plant Biomass Responses to Global Warming into Experimental, Ecological, Phylogenetic, and Intraspecific Components

    NASA Astrophysics Data System (ADS)

    Shao, J.

    2016-12-01

    Global warming has great consequences on plant growth and carbon accumulation, and eventually influences plant biomass. The results from numerous warming experiments showed that the responses of plant biomass to warming exhibited large variation. Some studies have attributed this variation to experimental design (e.g., warming facility and magnitude), thermal niche and plant traits (eg., growth form and leaf longevity). However, these factors could not fully explain the variation in plant biomass responses to warming. Species relatedness and intraspecific variation might be two missing factors which have not been considered yet. Therefore, in this study, we compiled a dataset from published papers which contained 284 species belonging to 185 genera and 63 families, to quantify the relative contributions of experimental design, ecological traits, phylogenetic relatedness and intraspecific variation to the plant biomass responses to experimental warming. Our results showed that 31.0% of the total variance could only be explained by phylogenetic information, with another 26.7% being jointly explained by phylogenetic information and experimental design or ecological traits. Intraspecific variation also accounted for 32.3% of total variance. Among experimental design and ecological traits, Growth temperature and warming magnitude contributed the largest variance, followed by plant growth form and experimental setting, with other factors had little contributions. These results highlighted the importance of phylogenetic information and intraspecific variation to plant biomass responses to warming, which had been largely neglected.

  10. Consistency of Estimated Global Water Cycle Variations Over the Satellite Era

    NASA Technical Reports Server (NTRS)

    Robertson, F. R.; Bosilovich, M. G.; Roberts, J. B.; Reichle, R. H.; Adler, R.; Ricciardulli, L.; Berg, W.; Huffman, G. J.

    2013-01-01

    Motivated by the question of whether recent indications of decadal climate variability and a possible "climate shift" may have affected the global water balance, we examine evaporation minus precipitation (E-P) variability integrated over the global oceans and global land from three points of view-remotely sensed retrievals / objective analyses over the oceans, reanalysis vertically-integrated moisture convergence (MFC) over land, and land surface models forced with observations-based precipitation, radiation and near-surface meteorology. Because monthly variations in area-averaged atmospheric moisture storage are small and the global integral of moisture convergence must approach zero, area-integrated E-P over ocean should essentially equal precipitation minus evapotranspiration (P-ET) over land (after adjusting for ocean and land areas). Our analysis reveals considerable uncertainty in the decadal variations of ocean evaporation when integrated to global scales. This is due to differences among datasets in 10m wind speed and near-surface atmospheric specific humidity (2m qa) used in bulk aerodynamic retrievals. Precipitation variations, all relying substantially on passive microwave retrievals over ocean, still have uncertainties in decadal variability, but not to the degree present with ocean evaporation estimates. Reanalysis MFC and P-ET over land from several observationally forced diagnostic and land surface models agree best on interannual variations. However, upward MFC (i.e. P-ET) reanalysis trends are likely related in part to observing system changes affecting atmospheric assimilation models. While some evidence for a low-frequency E-P maximum near 2000 is found, consistent with a recent apparent pause in sea-surface temperature (SST) rise, uncertainties in the datasets used here remain significant. Prospects for further reducing uncertainties are discussed. The results are interpreted in the context of recent climate variability (Pacific Decadal

  11. On the global mean temperature of the thermosphere

    NASA Technical Reports Server (NTRS)

    Roble, R. G.; Emergy, B. A.

    1983-01-01

    It is pointed out that the global mean temperature structure of the thermosphere above 120 km is primarily maintained by the absorption of solar extreme ultraviolet (EUV) flux at wavelengths less than 1025 A and solar ultraviolet (UV) flux. A number of previous calculations of the global mean temperature profile have determined that it is not possible to obtain agreement between the calculated global mean exospheric temperature and observed values. Since those studies, a considerable amount of new information on this problem has been obtained, including data obtained with the aid of the Atmospheric Explorer satellites. The present investigation is, therefore, concerned with a reexamination of the question whether there is enough solar UV radiation and auroral energy input to maintain the observed global mean temperature structure of the thermosphere above 120 km. It is found that for solar cycle minimum conditions there is an approximate balance between absorbed solar radiation and downward molecular thermal conduction.

  12. An examination of global variations of sunset NO2 as measured by SAGE II

    NASA Technical Reports Server (NTRS)

    Callis, L. B.

    1994-01-01

    Global variations of sunset NO2 are examined for the period October 24, 1984 through May 28, 1991 using Stratospheric Aerosol and Gas Experiment (SAGE) II data. Between 60 deg S and 60 deg N declining trends are observed at all latitudes and at all altitudes above 25 km. For the column NO2 above 25 km, the area-weighted integrated trend between these latitudes is -2.5%/year. The largest rates of decline (5%/year) are at mid to high latitudes in each hemisphere. Different temporal behavior is observed with latitude and in the two hemispheres. The largest percentage changes of NO2 from year to year are observed near 40 km at high latitudes and can be as large as 160%. These results and previously reported simulations suggest that a modulating polar source of NO(y) and variations in atmospheric temperature and advective transport both contribute to the observed NO2 variations.

  13. Variational Equation for Quantum Number Projection at Finite Temperature

    NASA Astrophysics Data System (ADS)

    Tanabe, Kosai; Nakada, Hitoshi

    2008-04-01

    To describe phase transitions in a finite system at finite temperature, we develop a formalism of the variation-after-projection (VAP) of quantum numbers based on the thermofield dynamics (TFD). We derive a new Bardeen-Cooper-Schrieffer (BCS)-type equation by variating the free energy with approximate entropy without violating Peierls inequality. The solution to the new BCS equation describes the S-shape in the specific heat curve and the superfluid-to-normal phase transition caused by the temperature effect. It simulates the exact quantum Monte Carlo results well.

  14. Interannual Variations of Shallow Firn Temperature at Greenland Summit

    NASA Technical Reports Server (NTRS)

    Jun, Li; Wang, W. L.; Zwally, H. J.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Firn-temperature profiles are calculated in a thermal model using continuous surface temperatures derived from Automatic Weather Station (AWS) data and passive microwave data in the Greenland Summit region during the period 1987-1999. The results show that significant interannual variations of mean summer (June to August) and annual temperatures occur in the top 15 m, in addition to the normal seasonal cycle of firn temperature. At 5 m depth, the seasonal cycle is damped to 13% of the surface seasonal amplitude, but even at 15 m about 1% or 0.6 C of the seasonal cycle persists. Both summer and mean annual temperatures decrease from 1987 to 1992, followed by a general increasing trend. Interannual variability is 5 C at the surface, but only is only dampened to 3.2 C at 10 m depth and 0.7 C at 15 m depth. Dampening of the interannual variability with depth is slower than dampening of the seasonal cycle, because of the longer time constant of the interannual variation. The warmer spring and summer temperatures experienced in the top 5 m, due to both the seasonal cycle and interannual variations, affect the rate of firn densification, which is non-linearly dependent on temperature. During the 12 year period 1987-1999, the mean annual surface temperature is -29.2 C, and the mean annual 15 m temperature is -30. 1 C, which is more than 1 C warmer than a 15-m borehole temperature representing the period of about 1959 and warmer than the best-fit temperature history by Alley and Koci back to 1500 A.D..

  15. Global surface air temperatures - Update through 1987

    NASA Technical Reports Server (NTRS)

    Hansen, James; Lebedeff, Sergej

    1988-01-01

    Data from meteorological stations show that surface air temperatures in the 1980s are the warmest in the history of instrumental records. The four warmest years on record are all in the 1980s, with the warmest years in the analysis being 1981 and 1987. The rate of warming between the mid-1960s and the present is higher than that which occurrred in the previous period of rapid warming between the 1880s and 1940.

  16. Global solar wind variations over the last four centuries.

    PubMed

    Owens, M J; Lockwood, M; Riley, P

    2017-01-31

    The most recent "grand minimum" of solar activity, the Maunder minimum (MM, 1650-1710), is of great interest both for understanding the solar dynamo and providing insight into possible future heliospheric conditions. Here, we use nearly 30 years of output from a data-constrained magnetohydrodynamic model of the solar corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global solar wind variations over the last 400 years. Relative to the modern era, the MM shows a factor 2 reduction in near-Earth heliospheric magnetic field strength and solar wind speed, and up to a factor 4 increase in solar wind Mach number. Thus solar wind energy input into the Earth's magnetosphere was reduced, resulting in a more Jupiter-like system, in agreement with the dearth of auroral reports from the time. The global heliosphere was both smaller and more symmetric under MM conditions, which has implications for the interpretation of cosmogenic radionuclide data and resulting total solar irradiance estimates during grand minima.

  17. Global solar wind variations over the last four centuries

    PubMed Central

    Owens, M. J.; Lockwood, M.; Riley, P.

    2017-01-01

    The most recent “grand minimum” of solar activity, the Maunder minimum (MM, 1650–1710), is of great interest both for understanding the solar dynamo and providing insight into possible future heliospheric conditions. Here, we use nearly 30 years of output from a data-constrained magnetohydrodynamic model of the solar corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global solar wind variations over the last 400 years. Relative to the modern era, the MM shows a factor 2 reduction in near-Earth heliospheric magnetic field strength and solar wind speed, and up to a factor 4 increase in solar wind Mach number. Thus solar wind energy input into the Earth’s magnetosphere was reduced, resulting in a more Jupiter-like system, in agreement with the dearth of auroral reports from the time. The global heliosphere was both smaller and more symmetric under MM conditions, which has implications for the interpretation of cosmogenic radionuclide data and resulting total solar irradiance estimates during grand minima. PMID:28139769

  18. Global solar wind variations over the last four centuries

    NASA Astrophysics Data System (ADS)

    Owens, M. J.; Lockwood, M.; Riley, P.

    2017-01-01

    The most recent “grand minimum” of solar activity, the Maunder minimum (MM, 1650–1710), is of great interest both for understanding the solar dynamo and providing insight into possible future heliospheric conditions. Here, we use nearly 30 years of output from a data-constrained magnetohydrodynamic model of the solar corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global solar wind variations over the last 400 years. Relative to the modern era, the MM shows a factor 2 reduction in near-Earth heliospheric magnetic field strength and solar wind speed, and up to a factor 4 increase in solar wind Mach number. Thus solar wind energy input into the Earth’s magnetosphere was reduced, resulting in a more Jupiter-like system, in agreement with the dearth of auroral reports from the time. The global heliosphere was both smaller and more symmetric under MM conditions, which has implications for the interpretation of cosmogenic radionuclide data and resulting total solar irradiance estimates during grand minima.

  19. Global biogeography of mating system variation in seed plants.

    PubMed

    Moeller, David A; Briscoe Runquist, Ryan D; Moe, Annika M; Geber, Monica A; Goodwillie, Carol; Cheptou, Pierre-Olivier; Eckert, Christopher G; Elle, Elizabeth; Johnston, Mark O; Kalisz, Susan; Ree, Richard H; Sargent, Risa D; Vallejo-Marin, Mario; Winn, Alice A

    2017-03-01

    Latitudinal gradients in biotic interactions have been suggested as causes of global patterns of biodiversity and phenotypic variation. Plant biologists have long speculated that outcrossing mating systems are more common at low than high latitudes owing to a greater predictability of plant-pollinator interactions in the tropics; however, these ideas have not previously been tested. Here, we present the first global biogeographic analysis of plant mating systems based on 624 published studies from 492 taxa. We found a weak decline in outcrossing rate towards higher latitudes and among some biomes, but no biogeographic patterns in the frequency of self-incompatibility. Incorporating life history and growth form into biogeographic analyses reduced or eliminated the importance of latitude and biome in predicting outcrossing or self-incompatibility. Our results suggest that biogeographic patterns in mating system are more likely a reflection of the frequency of life forms across latitudes rather than the strength of plant-pollinator interactions. © 2017 John Wiley & Sons Ltd/CNRS.

  20. Recent Development on the NOAA's Global Surface Temperature Dataset

    NASA Astrophysics Data System (ADS)

    Zhang, H. M.; Huang, B.; Boyer, T.; Lawrimore, J. H.; Menne, M. J.; Rennie, J.

    2016-12-01

    Global Surface Temperature (GST) is one of the most widely used indicators for climate trend and extreme analyses. A widely used GST dataset is the NOAA merged land-ocean surface temperature dataset known as NOAAGlobalTemp (formerly MLOST). The NOAAGlobalTemp had recently been updated from version 3.5.4 to version 4. The update includes a significant improvement in the ocean surface component (Extended Reconstructed Sea Surface Temperature or ERSST, from version 3b to version 4) which resulted in an increased temperature trends in recent decades. Since then, advancements in both the ocean component (ERSST) and land component (GHCN-Monthly) have been made, including the inclusion of Argo float SSTs and expanded EOT modes in ERSST, and the use of ISTI databank in GHCN-Monthly. In this presentation, we describe the impact of those improvements on the merged global temperature dataset, in terms of global trends and other aspects.

  1. Global Temperature and Salinity Pilot Project

    NASA Technical Reports Server (NTRS)

    Searle, Ben

    1992-01-01

    Data exchange and data management programs have been evolving over many years. Within the international community there are two main programs to support the exchange, management and processing of real time and delayed mode data. The Intergovernmental Oceanographic Commission (IOC) operate the International Oceanographic Data and Information Exchange (IODE) program which coordinates the exchange of delayed mode data between national oceanographic data centers, World Data Centers and the user community. The Integrated Global Ocean Services System is a joint IOC/World Meteorological Organization (WMO) program for the exchange and management of real-time data. These two programs are complemented by mechanisms that have been established within scientific programs to exchange and manage project data sets. In particular TOGA and WOCE have identified a data management requirement and established the appropriate infrastructure to achieve this. Where GTSPP fits into this existing framework is discussed.

  2. Robust Optimization of a MEMS Accelerometer Considering Temperature Variations

    PubMed Central

    Liu, Guangjun; Yang, Feng; Bao, Xiaofan; Jiang, Tao

    2015-01-01

    A robust optimization approach for a MEMS accelerometer to minimize the effects of temperature variations is presented. The mathematical model of the accelerometer is built. The effects of temperature variations on the output performance of the accelerometer are determined, and thermal deformation of the accelerometer is analyzed. The deviations of the output capacitance and resonance frequency due to temperature fluctuations are calculated and discussed. The sensitivity analysis method is employed to determine the design variables for robust optimization and find out the key structural parameters that have most significant influence on the output capacitance and resonance frequency of the accelerometer. The mathematical model and procedure for the robust optimization of the accelerometer are proposed. The robust optimization problem is solved and discussed. The robust optimization results show that an optimized accelerometer with high sensitivity, high temperature robustness and decoupling structure is finally obtained. PMID:25785308

  3. Robust optimization of a MEMS accelerometer considering temperature variations.

    PubMed

    Liu, Guangjun; Yang, Feng; Bao, Xiaofan; Jiang, Tao

    2015-03-16

    A robust optimization approach for a MEMS accelerometer to minimize the effects of temperature variations is presented. The mathematical model of the accelerometer is built. The effects of temperature variations on the output performance of the accelerometer are determined, and thermal deformation of the accelerometer is analyzed. The deviations of the output capacitance and resonance frequency due to temperature fluctuations are calculated and discussed. The sensitivity analysis method is employed to determine the design variables for robust optimization and find out the key structural parameters that have most significant influence on the output capacitance and resonance frequency of the accelerometer. The mathematical model and procedure for the robust optimization of the accelerometer are proposed. The robust optimization problem is solved and discussed. The robust optimization results show that an optimized accelerometer with high sensitivity, high temperature robustness and decoupling structure is finally obtained.

  4. Systematic variations in morphological characteristics of global transform faults

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Lin, J.

    2015-12-01

    We quantify systematic variations in morphological characteristics of global transform faults and investigate their dependence on spreading rate, local magma supply, and other tectonic variables. Detailed analyses were conducted on 78 transform faults where high-resolution multibeam bathymetry data are available. The investigated transform systems span a wide range of spreading rate and local magma supply, including examples from the East Pacific Rise, Juan de Fuca Ridge, Chile Rise, Pacific-Antarctic Ridge, Southeast Indian Ridge, Central Indian Ridge, Mid-Atlantic Ridge, American-Antarctic Ridge, Southwest Indian Ridge, and other systems. The analyses revealed systematic global and local variations in transform morphological characteristics: (1) The average transform age offset and depths shows a moderate increase with decreasing spreading rate: 1.0 Ma and 3.6 km (s = 0.21 km), 1.5 Ma (s = 0.9 Ma) and 3.8 km (s = 0.12 km), 2.2 Ma (s = 1.7 Ma and 4.5 km (s = 0.14 km), and 5.3 Ma (s = 3.5 Ma) and 4.8 km (s = 0.20 km) for the fast, intermediate fast, slow, and ultraslow ridges, respectively, corresponding to average transform length of 111 km (s = 75 km), 81 km (s = 73 km), 71 km (s = 40 km), and 92 km (s = 49 km), respectively. (2) Morphological "hooks", i.e., axial morphological highs that curve around a ridge-transform intersection, appear to be most distinctive in regions of relatively robust magma supply, especially at fast and intermediate fast ridges. (3) In contrast, "nodal basins" usually develop at the ridge-transform intersection of relatively slow spreading systems and low magma supply. The depth of the nodal basin appears to moderately increase with decreasing spreading rate with an average depth of 3.8 km (s = 0.5 km) for the investigated systems. Thus the calculated values of average transform fault depth, ridge-transform intersection depth, and age-offset of the investigated systems all appear to increase with decreasing spreading rate. However, the

  5. GOAT (Global Oxygen And Temperature) Mapping

    NASA Astrophysics Data System (ADS)

    Slanger, T. G.; Kostko, O.; Pejakovic, D. A.; Kalogerakis, K. S.

    2012-04-01

    The O2(b1Σg+ - X3Σg-) Atmospheric Band system has been studied extensively since the days of Fraunhofer, who first showed that solar photoabsorption in the 762 nm region was caused by terrestrial oxygen; in this case, the 0-0 band of the b - X system. The O2(b) state is generated by two different mechanisms in the atmosphere: by O(3P ) atom recombination, where O2(b) is one of several excited O2 states produced, and by the energy transfer from O(1D) to O2, where the products are O2(b, v = 0, 1). The latter is an ionospheric process and is the case of interest here. Recent studies at SRI International have demonstrated that O2(b, v = 1) is the predominant product of the energy transfer, with the nascent [v = 1]/[v = 0] ratio being close to 4 and temperature independent. Collisional quenching of b(1) by O2, to produce b(0), proceeds six orders of magnitude faster than b(0) quenching [Slanger and Copeland, 2003]. As a consequence, the [b - X(1-1)]/[b - X(0-0)] intensity ratio as a function of thermospheric altitude shows the degree to which b(1) has been converted to b(0), which can be interpreted in terms of atmospheric composition. Of the three colliders - O2, O(3P ), and N2 - it is the first two that control the b(1) → b(0) relaxation rate. To observe the b(v = 0, 1) emission requires space-based measurements in the 755-780 nm region of the 0-0 and 1-1 bands. In addition to the varying intensity ratio of the two bands, the shapes will differ as a function of temperature as the rotational temperature changes. Thus, observations of the shapes and the relative intensities of the two bands will simultaneously lead to information on temperature and on the [O2] + [O(3P )] densities as a function of altitude. The technique is relevant to the dayglow and to the portion of the night when O(1D) is still detectable. T. G. Slanger and R. A. Copeland, Chem. Rev. 103, 4731-65, 2003. Supported by NASA ITM Grant NNX10AL08G and NSF Aeronomy Grant AGS-0937317.

  6. Gentic variation for high temperature tolerance in maize

    USDA-ARS?s Scientific Manuscript database

    As global warming becomes inevitable, the sustainability of agricultural production in US and worldwide faces serious threat from extreme weather conditions, such as drought and high temperature (heat) stresses. While drought stress can be alleviated through irrigation, little can be done with high ...

  7. Modern average global sea-surface temperature

    USGS Publications Warehouse

    Schweitzer, Peter N.

    1993-01-01

    The data contained in this data set are derived from the NOAA Advanced Very High Resolution Radiometer Multichannel Sea Surface Temperature data (AVHRR MCSST), which are obtainable from the Distributed Active Archive Center at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The JPL tapes contain weekly images of SST from October 1981 through December 1990 in nine regions of the world ocean: North Atlantic, Eastern North Atlantic, South Atlantic, Agulhas, Indian, Southeast Pacific, Southwest Pacific, Northeast Pacific, and Northwest Pacific. This data set represents the results of calculations carried out on the NOAA data and also contains the source code of the programs that made the calculations. The objective was to derive the average sea-surface temperature of each month and week throughout the whole 10-year series, meaning, for example, that data from January of each year would be averaged together. The result is 12 monthly and 52 weekly images for each of the oceanic regions. Averaging the images in this way tends to reduce the number of grid cells that lack valid data and to suppress interannual variability.

  8. Local warming: daily temperature change influences belief in global warming.

    PubMed

    Li, Ye; Johnson, Eric J; Zaval, Lisa

    2011-04-01

    Although people are quite aware of global warming, their beliefs about it may be malleable; specifically, their beliefs may be constructed in response to questions about global warming. Beliefs may reflect irrelevant but salient information, such as the current day's temperature. This replacement of a more complex, less easily accessed judgment with a simple, more accessible one is known as attribute substitution. In three studies, we asked residents of the United States and Australia to report their opinions about global warming and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual believed more in and had greater concern about global warming than did respondents who thought that day was colder than usual. They also donated more money to a global-warming charity if they thought that day seemed warmer than usual. We used instrumental variable regression to rule out some alternative explanations.

  9. Genetic variation of body temperature of Coturnix coturnix in two ambient temperatures.

    PubMed

    Becker, W A; Harrison, P

    1975-05-01

    Coturnix quail were placed in an environmental chamber maintained at 21 degree C. and rectal temperatures taken. The birds were subjected to an abrupt change to 36 degree C. and the temperatures taken hourly for eight hours and at 25, 38 and 72 hours. Females had higher temperatures than males. When birds were moved to 36 degrees C. their temperatures rose rapidly and then dropped to a level higher than when birds were in the 21 degrees C. chamber. The genetic and total variation estimated from the analysis of variance method decreased under this sudden thermal stress condition. Birds kept in 36 degrees C. for three weeks were shifted to 21 degrees C. Their body temperature dropped sharply and then increased to a level lower than that obtained in the 36 degrees C. environment. The genetic variation was essentially zero when shifted to a lower temperature while the total variation increased.

  10. Forcing, feedback and internal variability in global temperature trends.

    PubMed

    Marotzke, Jochem; Forster, Piers M

    2015-01-29

    Most present-generation climate models simulate an increase in global-mean surface temperature (GMST) since 1998, whereas observations suggest a warming hiatus. It is unclear to what extent this mismatch is caused by incorrect model forcing, by incorrect model response to forcing or by random factors. Here we analyse simulations and observations of GMST from 1900 to 2012, and show that the distribution of simulated 15-year trends shows no systematic bias against the observations. Using a multiple regression approach that is physically motivated by surface energy balance, we isolate the impact of radiative forcing, climate feedback and ocean heat uptake on GMST--with the regression residual interpreted as internal variability--and assess all possible 15- and 62-year trends. The differences between simulated and observed trends are dominated by random internal variability over the shorter timescale and by variations in the radiative forcings used to drive models over the longer timescale. For either trend length, spread in simulated climate feedback leaves no traceable imprint on GMST trends or, consequently, on the difference between simulations and observations. The claim that climate models systematically overestimate the response to radiative forcing from increasing greenhouse gas concentrations therefore seems to be unfounded.

  11. Global non-linear effect of temperature on economic production

    NASA Astrophysics Data System (ADS)

    Burke, Marshall; Hsiang, Solomon M.; Miguel, Edward

    2015-11-01

    Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human-natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

  12. Global non-linear effect of temperature on economic production.

    PubMed

    Burke, Marshall; Hsiang, Solomon M; Miguel, Edward

    2015-11-12

    Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human-natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

  13. Regionalized Temperature Variations in the Upper 400 km of the Earth's Mantle

    NASA Technical Reports Server (NTRS)

    Tralli, D. M.; Ita, J. J.

    1995-01-01

    Tectonically regionalized variations in the temperature of the upper 400 km of the Earth's mantle are estimated from analysis of global seismic travel-time data catalogued by the International Seismological Centre (ISC). Seismic parameter profiles are determined from estimates of P and S velocities obtained by tau inversion, and summary phase diagrams for the olivine and pyroxene- garnet subsystems are constructed in conjunction with a thermodynamic potential formulation.

  14. Global, seasonal cloud variations from satellite radiance measurements. II - Cloud properties and radiative effects

    NASA Technical Reports Server (NTRS)

    Rossow, William B.; Lacis, Andrew A.

    1990-01-01

    Cloud and surface radiative properties and their effects on the earth and surface radiation budgets are obtained based on global daily visible and IR radiance measurements. The magnitude of cloud property variations and their effects on radiation increase strongly with decreasing space/time scales. Cloud properties are systematically different between land and ocean, with ocean having larger cloud cover with somewhat larger optical thicknesses and lower cloud top altitudes. Although cloud variations appear to be the primary cause of regional radiation budget variability at 5-30 daytime scales, the effects of their seasonal variations at larger spatial scales are less important than the changes associated with changes in solar declination and atmospheric/surface temperatures. The largest seasonal variations in radiation occur in the 30-60 deg latitude band in each hemisphere. Although clouds have a net cooling effect on the global, annual mean radiation balance at both the top of the atmosphere and the surface, their net effect on regional, seasonal balances is much more varied.

  15. Global, seasonal cloud variations from satellite radiance measurements. II - Cloud properties and radiative effects

    NASA Technical Reports Server (NTRS)

    Rossow, William B.; Lacis, Andrew A.

    1990-01-01

    Cloud and surface radiative properties and their effects on the earth and surface radiation budgets are obtained based on global daily visible and IR radiance measurements. The magnitude of cloud property variations and their effects on radiation increase strongly with decreasing space/time scales. Cloud properties are systematically different between land and ocean, with ocean having larger cloud cover with somewhat larger optical thicknesses and lower cloud top altitudes. Although cloud variations appear to be the primary cause of regional radiation budget variability at 5-30 daytime scales, the effects of their seasonal variations at larger spatial scales are less important than the changes associated with changes in solar declination and atmospheric/surface temperatures. The largest seasonal variations in radiation occur in the 30-60 deg latitude band in each hemisphere. Although clouds have a net cooling effect on the global, annual mean radiation balance at both the top of the atmosphere and the surface, their net effect on regional, seasonal balances is much more varied.

  16. Unabated global surface temperature warming: evaluating the evidence

    NASA Astrophysics Data System (ADS)

    Karl, T. R.; Arguez, A.

    2015-12-01

    New insights related to time-dependent bias corrections in global surface temperatures have led to higher rates of warming over the past few decades than previously reported in the IPCC Fifth Assessment Report (2014). Record high global temperatures in the past few years have also contributed to larger trends. The combination of these factors and new analyses of the rate of temperature change show unabated global warming since at least the mid-Twentieth Century. New time-dependent bias corrections account for: (1) differences in temperatures measured from ships and drifting buoys; (2) improved corrections to ship measured temperatures; and (3) the larger rates of warming in polar regions (particularly the Arctic). Since 1951, the period over which IPCC (2014) attributes over half of the observed global warming to human causes, it is shown that there has been a remarkably robust and sustained warming, punctuated with inter-annual and decadal variability. This finding is confirmed through simple trend analysis and Empirical Mode Decomposition (EMD). Trend analysis however, especially for decadal trends, is sensitive to selection bias of beginning and ending dates. EMD has no selection bias. Additionally, it can highlight both short- and long-term processes affecting the global temperature times series since it addresses both non-linear and non-stationary processes. For the new NOAA global temperature data set, our analyses do not support the notion of a hiatus or slowing of long-term global warming. However, sub-decadal periods of little (or no warming) and rapid warming can also be found, clearly showing the impact of inter-annual and decadal variability that previously has been attributed to both natural and human-induced non-greenhouse forcings.

  17. Tree growth variation in the tropical forest: understanding effects of temperature, rainfall and CO2.

    PubMed

    Schippers, Peter; Sterck, Frank; Vlam, Mart; Zuidema, Pieter A

    2015-01-28

    Tropical forest responses to climatic variability have important consequences for global carbon cycling, but are poorly understood. As empirical, correlative studies cannot disentangle the interactive effects of climatic variables on tree growth, we used a tree growth model (IBTREE) to unravel the climate effects on different physiological pathways and in turn on stem growth variation. We parameterized the model for canopy trees of Toona ciliata (Meliaceae) from a Thai monsoon forest and compared predicted and measured variation from a tree-ring study over a 30-year period. We used historical climatic variation of minimum and maximum day temperature, precipitation and carbon dioxide (CO2 ) in different combinations to estimate the contribution of each climate factor in explaining the inter-annual variation in stem growth. Running the model with only variation in maximum temperature and rainfall yielded stem growth patterns that explained almost 70% of the observed inter-annual variation in stem growth. Our results show that maximum temperature had a strong negative effect on the stem growth by increasing respiration, reducing stomatal conductance and thus mitigating a higher transpiration demand, and - to a lesser extent - by directly reducing photosynthesis. Although stem growth was rather weakly sensitive to rain, stem growth variation responded strongly and positively to rainfall variation owing to the strong inter-annual fluctuations in rainfall. Minimum temperature and atmospheric CO2 concentration did not significantly contribute to explaining the inter-annual variation in stem growth. Our innovative approach - combining a simulation model with historical data on tree-ring growth and climate - allowed disentangling the effects of strongly correlated climate variables on growth through different physiological pathways. Similar studies on different species and in different forest types are needed to further improve our understanding of the sensitivity of

  18. Responding to the Need for Better Global Temperature Data

    NASA Astrophysics Data System (ADS)

    Lawrimore, Jay; Rennie, Jared; Thorne, Peter

    2013-02-01

    Since the 1990s a number of national institutions have developed and maintained global data sets of land surface air temperature [Peterson and Vose, 1997; Hansen et al., 2010; Jones et al., 2012; Menne et al., 2012]. These efforts have led to great advances in understanding how Earth's temperatures have varied and changed. They also serve as essential sources of a fundamental climate variable, which is crucial for interpreting climate evolution in response to the interplay of radiative forcing, climate feedbacks, and ocean heating [e.g., Hansen et al., 2011]. However, more can be done to improve global surface temperature collections while enhancing data management, access, and public transparency with which data are collected, processed, and converted into climate information. To address these needs, the International Surface Temperature Initiative (ISTI), which began through a partnership of scientists from around the world [Thorne et al., 2011], released its first beta version of a global land surface databank in October 2012.

  19. The reliability of global and hemispheric surface temperature records

    NASA Astrophysics Data System (ADS)

    Jones, Philip

    2016-03-01

    The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time.

  20. Climatic change controls productivity variation in global grasslands

    NASA Astrophysics Data System (ADS)

    Gao, Qingzhu; Zhu, Wenquan; Schwartz, Mark W.; Ganjurjav, Hasbagan; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Williamson, Matthew A.; Li, Yue

    2016-05-01

    Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2–71.2% during 1982–2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms.

  1. Climatic change controls productivity variation in global grasslands.

    PubMed

    Gao, Qingzhu; Zhu, Wenquan; Schwartz, Mark W; Ganjurjav, Hasbagan; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Williamson, Matthew A; Li, Yue

    2016-05-31

    Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2-71.2% during 1982-2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms.

  2. Climatic change controls productivity variation in global grasslands

    PubMed Central

    Gao, Qingzhu; Zhu, Wenquan; Schwartz, Mark W.; Ganjurjav, Hasbagan; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Williamson, Matthew A.; Li, Yue

    2016-01-01

    Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2–71.2% during 1982–2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms. PMID:27243565

  3. Spatial and Temporal Variation of the Vertical Column Density of the Oxygen Dimer O4 on a Global Scale

    NASA Astrophysics Data System (ADS)

    Dörner, Steffen; Wang, Yang; Wagner, Thomas

    2017-04-01

    Measurements of the oxygen dimer O4 are often used in remote sensing applications to infer information on the atmospheric light path distribution. While such information is interesting in itself, it can also be used to retrieve properties of clouds and aerosols. The concentration of O4 is usually expressed as the square of the oxygen concentration, which can be derived from atmospheric temperature and pressure profiles. Accordingly, the atmospheric O4 concentration and the so called O4 vertical column density (VCD, the vertically integrated O4 concentration), change with variations of atmospheric temperature and pressure. Variations of the O4 VCD at a given location can be up to 20 % and thus have to be considered in the analysis and interpretation of O4 observations. Another important aspect is the temperature dependency of the O4 cross section, which can lead to systematic errors of about 10 % for a temperature mismatch of 30 K. This temperature dependency can be accounted for by using an empirically determined temperature dependent scaling factor to correct the atmospheric O4 VCD. This leads to a temperature independent O4 VCD(T_const), which can be then used for the interpretation of O4 results obtained using a cross section of the same temperature. In this study we use global meteorological data sets of temperature, pressure and humidity from ECMWF to calculate the corresponding O4 VCD. We also apply our empirical correction for the temperature dependence of the O4 cross-section to convert the O4 VCDs into a temperature independent O4 VCD(298 K). Our results indicate that due to variations of temperature and pressure, the local O4 VCD(298 K) can vary by up to 30 % while variations on a global scale are expected to be larger. In addition to the integrated VCD, we use the meteorological data set to quantify variations in the vertical profile of O_4.

  4. Global exospheric temperatures from ESRO 4 scale height measurements

    NASA Technical Reports Server (NTRS)

    Keating, G. M.; Prior, E. J.; Lake, L. R.; Nicholson, J. Y., III; Fricke, K.

    1977-01-01

    The scale height temperatures considered are based on molecular nitrogen measurements by the gas analyzer aboard the ESRO 4 in the altitude range from 280 to 310 km during the interval from December 1972 to April 1974, a period of low solar activity. At the altitude of measurement during the considered period, the scale height temperature is essentially the exospheric temperature. The mean scale height temperature derived from 1833 independent N2 scale heights is 708 K. It is concluded that the ESRO 4 data provides evidence of mean global temperatures of less than 800 K.

  5. Recent geographic convergence in diurnal and annual temperature cycling flattens global thermal profiles

    NASA Astrophysics Data System (ADS)

    Wang, George; Dillon, Michael E.

    2014-11-01

    Warming mean temperatures over the past century have probably shifted distributions, altered phenologies, increased extinction risks, and impacted agriculture and human health. However, knowledge of mean temperatures alone does not provide a complete understanding either of changes in the climate itself or of how changing climate will affect organisms. Temporal temperature variation, primarily driven by daily and annual temperature cycles, has profound effects on organism physiology and ecology, yet changes in temperature cycling over the past 40 years are still poorly understood. Here we estimate global changes in the magnitudes of diurnal and annual temperature cycles from 1975 to 2013 from an analysis of over 1.4 billion hourly temperature measurements from 7,906 weather stations. Increases in daily temperature variation since 1975 in polar (1.4 °C), temperate (1.0 °C) and tropical (0.3 °C) regions parallel increases in mean temperature. Concurrently, magnitudes of annual temperature cycles decreased by 0.6 °C in polar regions, increased by 0.4 °C in temperate regions, and remained largely unchanged in tropical regions. Stronger increases in daily temperature cycling relative to changes in annual temperature cycling in temperate and polar regions mean that, with respect to diurnal and annual cycling, the world is flattening as temperate and polar regions converge on tropical temperature cycling profiles.

  6. Global Average Brightness Temperature for April 2003

    NASA Image and Video Library

    2003-06-02

    This image shows average temperatures in April, 2003, observed by AIRS at an infrared wavelength that senses either the Earth's surface or any intervening cloud. Similar to a photograph of the planet taken with the camera shutter held open for a month, stationary features are captured while those obscured by moving clouds are blurred. Many continental features stand out boldly, such as our planet's vast deserts, and India, now at the end of its long, clear dry season. Also obvious are the high, cold Tibetan plateau to the north of India, and the mountains of North America. The band of yellow encircling the planet's equator is the Intertropical Convergence Zone (ITCZ), a region of persistent thunderstorms and associated high, cold clouds. The ITCZ merges with the monsoon systems of Africa and South America. Higher latitudes are increasingly obscured by clouds, though some features like the Great Lakes, the British Isles and Korea are apparent. The highest latitudes of Europe and Eurasia are completely obscured by clouds, while Antarctica stands out cold and clear at the bottom of the image. http://photojournal.jpl.nasa.gov/catalog/PIA00427

  7. Variations in the corneal surface temperature with contact lens wear.

    PubMed

    Ooi, E H; Ng, E Y K; Purslow, C; Acharya, R

    2007-05-01

    This paper presents the two-dimensional simulation of heat propagation in the human eye model during contact lens wear with finite element analysis. Three types of contact lens are studied: Lotrafilcon A, Balafilcon A, and Etafilcon A. The models are solved for both steady and transient solutions. The corneal surface temperature during contact lens wear is found to decrease (average, 0.52 +/- 0.05 degrees C compared with a bare cornea for all lens types). A contact lens with a higher water content has a lower steady state temperature than a contact lens with a lower water content does. Various initial temperatures for the contact lens are found to affect the first 400 s of the temperature variation. When the initial temperature is lower than the corneal temperature, a reduction in temperature is observed during contact lens insertion while the opposite is observed when the initial temperature is higher than the corneal temperature. The increase in evaporation rate when a contact lens is worn increases the cooling effect on the ocular surface. This is suggested to be the cause of lower corneal surface temperature when wearing a contact lens.

  8. Modeling of global variations and ring shadowing in Saturn's ionosphere

    NASA Astrophysics Data System (ADS)

    Moore, L. E.; Mendillo, M.; Müller-Wodarg, I. C. F.; Murr, D. L.

    2004-12-01

    A time-dependent one-dimensional model of Saturn's ionosphere has been developed as an intermediate step towards a fully coupled Saturn Thermosphere-Ionosphere Model (STIM). A global circulation model (GCM) of the thermosphere provides the latitude and local time dependent neutral atmosphere, from which a globally varying ionosphere is calculated. Four ion species are used (H +, H +2, H +3, and He +) with current cross-sections and reaction rates, and the SOLAR2000 model for the Sun's irradiance. Occultation data from the Voyager photopolarimeter system (PPS) are adapted to model the radial profile of the ultraviolet (UV) optical depth of the rings. Diurnal electron density peak values and heights are generated for all latitudes and two seasons under solar minimum and solar maximum conditions, both with and without shadowing from the rings. Saturn's lower ionosphere is shown to be in photochemical equilibrium, whereas diffusive processes are important in the topside. In agreement with previous 1-D models, the ionosphere is dominated by H + and H +3, with a peak electron density of ˜10 electrons cm -3. At low- and mid-latitudes, H + is the dominant ion, and the electron density exhibits a diurnal maximum during the mid-afternoon. At higher latitudes and shadowed latitudes (smaller ionizing fluxes), the diurnal maximum retreats towards noon, and the ratio of [H +]/[H +3] decreases, with H +3 becoming the dominant ion at altitudes near the peak (˜1200-1600 km) for noon-time hours. Shadowing from the rings leads to attenuation of solar flux, the magnitude and latitudinal structure of which is seasonal. During solstice, the season for the Cassini spacecraft's encounter with Saturn, attenuation has a maximum of two orders of magnitude, causing a reduction in modeled peak electron densities and total electron column contents by as much as a factor of three. Calculations are performed that explore the parameter space for charge-exchange reactions of H + with

  9. Has global warming modified the relationship between sunspot numbers and global temperatures?

    NASA Astrophysics Data System (ADS)

    Kristoufek, Ladislav

    2017-02-01

    We study time evolution of the relationship between sunspot numbers and global temperatures between 1880 and 2016 using wavelet coherence framework. The results suggest that the relationship is stable in time. Changes in the sunspot numbers precede changes in the temperatures by more than two years as suggested by the wavelet phase differences. This leading position of the sun activity is stable in time as well. However, the relationship has been disturbed by increasing CO2 emissions since 1960s. Without controlling for the effect of possible global warming, or more precisely the positive connection between increasing CO2 emissions and the global temperatures, the findings would have been quite different. Combination of the cointegration analysis and wavelet coherence framework has enabled uncovering a hidden relationship between the solar activity and global temperatures, and possibly explaining equivocal results in the topical literature.

  10. Global average net radiation sensitivity to cloud amount variations

    SciTech Connect

    Karner, O.

    1993-12-01

    Time series analysis performed using an autoregressive model is carried out to study monthly oscillations in the earth radiation budget (ERB) at the top of the atmosphere (TOA) and cloud amount estimates on a global basis. Two independent cloud amount datasets, produced elsewhere by different authors, and the ERB record based on the Nimbus-7 wide field-of-view 8-year (1978-86) observations are used. Autoregressive models are used to eliminate the effects of the earth`s orbit eccentricity on the radiation budget and cloud amount series. Nonzero cross correlation between the residual series provides a way of estimating the contribution of the cloudiness variations to the variance in the net radiation. As a result, a new parameter to estimate the net radiation sensitivity at the TOA to changes in cloud amount is introduced. This parameter has a more general character than other estimates because it contains time-lag terms of different length responsible for different cloud-radiation feedback mechanisms in the earth climate system. Time lags of 0, 1, 12, and 13 months are involved. Inclusion of the zero-lag term only shows that the albedo effect of clouds dominates, as is known from other research. Inclusion of all four terms leads to an average quasi-annual insensitivity. Approximately 96% of the ERB variance at the TOA can be explained by the eccentricity factor and 1% by cloudiness variations, provided that the data used are without error. Although the latter assumption is not fully correct, the results presented allow one to estimate the contribution of current cloudiness changes to the net radiation variability. Two independent cloud amount datasets have very similar temporal variability and also approximately equal impact on the net radiation at the TOA.

  11. Variations of nighttime enhancement in neutral and ion temperatures

    NASA Astrophysics Data System (ADS)

    Ruan, H.; Lei, J.; Wang, W.

    2014-12-01

    The midnight temperature maximum (MTM) over equatorial region has been reported since 1970s, while the recently reported enhancement of the nighttime thermospheric and ion temperatures at middle and high latitudes is suggested extending from the equatorial region. Recently, we used both ground-based and satellite measurements to investigate the solar activity, seasonal and latitudinal dependences of the nighttime temperature variation at different latitudes. It was found that the postmidnight enhancement occurred in neutral and ion temperatures over middle and high latitudes with a seasonal dependence. Moreover, the CHAMP neutral density data were used to reveal the averaged patterns of the signature of the MTM, which shows the extension of the nighttime enhancement from the equatorial region to higher latitudes. In this presentation, we will also compare the observed data with the results from the coupled ionosphere and thermosphere model to explore the possible mechanisms responsible for the nighttime temperature enhancements at different latitudes.

  12. Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales.

    PubMed

    Gilman, Sarah E; Wethey, David S; Helmuth, Brian

    2006-06-20

    Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species' organismal body temperature. This simple change is unlikely because an organism's body temperature is determined by a complex series of interactions between the organism and its environment. Using a biophysical model, validated with 5 years of field observations, we examined the relationship between environmental temperature change and body temperature of the intertidal mussel Mytilus californianus over 1,600 km of its geographic distribution. We found that at all locations examined simulated changes in air or water temperature always produced less than equivalent changes in the daily maximum mussel body temperature. Moreover, the magnitude of body temperature change was highly variable, both within and among locations. A simulated 1 degrees C increase in air or water temperature raised the maximum monthly average of daily body temperature maxima by 0.07-0.92 degrees C, depending on the geographic location, vertical position, and temperature variable. We combined these sensitivities with predicted climate change for 2100 and calculated increases in monthly average maximum body temperature of 0.97-4.12 degrees C, depending on location and climate change scenario. Thus geographic variation in body temperature sensitivity can modulate species' experiences of climate change and must be considered when predicting the biological consequences of climate change.

  13. Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales

    PubMed Central

    Gilman, Sarah E.; Wethey, David S.; Helmuth, Brian

    2006-01-01

    Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species’ organismal body temperature. This simple change is unlikely because an organism’s body temperature is determined by a complex series of interactions between the organism and its environment. Using a biophysical model, validated with 5 years of field observations, we examined the relationship between environmental temperature change and body temperature of the intertidal mussel Mytilus californianus over 1,600 km of its geographic distribution. We found that at all locations examined simulated changes in air or water temperature always produced less than equivalent changes in the daily maximum mussel body temperature. Moreover, the magnitude of body temperature change was highly variable, both within and among locations. A simulated 1°C increase in air or water temperature raised the maximum monthly average of daily body temperature maxima by 0.07–0.92°C, depending on the geographic location, vertical position, and temperature variable. We combined these sensitivities with predicted climate change for 2100 and calculated increases in monthly average maximum body temperature of 0.97–4.12°C, depending on location and climate change scenario. Thus geographic variation in body temperature sensitivity can modulate species’ experiences of climate change and must be considered when predicting the biological consequences of climate change. PMID:16763050

  14. The midlatitude North American background aerosol and global aerosol variation.

    PubMed

    Hidy, George M; Blanchard, Charles L

    2005-11-01

    Protocols for the particulate matter (PM) National Ambient Air Quality Standards (NAAQS), and the Regional Haze Rule (RHR) give two complementary definitions for "natural" background airborne particle concentrations in the United States. The definition for the NAAQS derives largely from reported annual averages, whereas the definition for the RHR takes into account the frequency of occurrence of a range of visibility conditions estimated using fine particle composition. These definitions are simple, static representations of background or "unmanageable" aerosol conditions in the United States. An accumulation of data from rural-remote sites representing global conditions indicates that the airborne particle concentrations are highly variable. Observational campaigns show weather-related variations, including incidents of regional or intercontinental transport of pollution that influence background aerosol levels over midlatitude North America. Defining a background in North America based on long-term observations relies mainly on the remote-rural IMPROVE network in the United States, with a few additional measurements from Canada. Examination of the frequency of occurrence of mass concentrations and particle components provides insight not only about annual median conditions but also the variability of apparent background conditions. The results of this analysis suggest that a more elaborate approach to defining an unmanageable background could improve the present approach taken for information input into the U.S. regulatory process. An approach interpreting the continental gradients in fine PM (PM2.5) concentrations and composition may be warranted.

  15. Global Surface Temperature Change and Uncertainties Since 1861

    NASA Technical Reports Server (NTRS)

    Shen, Samuel S. P.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The objective of this talk is to analyze the warming trend and its uncertainties of the global and hemi-spheric surface temperatures. By the method of statistical optimal averaging scheme, the land surface air temperature and sea surface temperature observational data are used to compute the spatial average annual mean surface air temperature. The optimal averaging method is derived from the minimization of the mean square error between the true and estimated averages and uses the empirical orthogonal functions. The method can accurately estimate the errors of the spatial average due to observational gaps and random measurement errors. In addition, quantified are three independent uncertainty factors: urbanization, change of the in situ observational practices and sea surface temperature data corrections. Based on these uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61 +/- 0.16 C between 1861 and 2000. This lecture will also touch the topics on the impact of global change on nature and environment. as well as the latest assessment methods for the attributions of global change.

  16. Global Surface Temperature Change and Uncertainties Since 1861

    NASA Technical Reports Server (NTRS)

    Shen, Samuel S. P.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The objective of this talk is to analyze the warming trend and its uncertainties of the global and hemi-spheric surface temperatures. By the method of statistical optimal averaging scheme, the land surface air temperature and sea surface temperature observational data are used to compute the spatial average annual mean surface air temperature. The optimal averaging method is derived from the minimization of the mean square error between the true and estimated averages and uses the empirical orthogonal functions. The method can accurately estimate the errors of the spatial average due to observational gaps and random measurement errors. In addition, quantified are three independent uncertainty factors: urbanization, change of the in situ observational practices and sea surface temperature data corrections. Based on these uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61 +/- 0.16 C between 1861 and 2000. This lecture will also touch the topics on the impact of global change on nature and environment. as well as the latest assessment methods for the attributions of global change.

  17. Coherent variations of monthly mean total ozone and lower stratospheric temperature

    NASA Technical Reports Server (NTRS)

    Randel, William J.; Cobb, Janel B.

    1994-01-01

    Space-time patterns of correlation between total ozone and lower stratospheric temperature are documented, based on 14 years (1979-1992) of global monthly mean observations. Data are obtained from the total ozone mapping spectrometer (TOMS) and microwave sounding unit (MSU) channel 4, the latter being a weighted mean temperature of the 150- to 50-mbar layer. These data are analyzed (separately) for linear trend, solar cycle, quasi-biennial oscillation (QBO), and El Nino-Southern Oscillation (ENSO) variations via linear regression: significant signals are identified for each term, and the corresponding structures in ozone and temperature are found to be highly coherent. The temperature trends derived here show significant cooling of the lower stratosphere over Northern Hemisphere (NH) midlatitudes in winter-spring and over Antarctica in Southern Hemisphere (SH) spring; the overall space-time patterns are similar to those determined for ozone trends. Interestingly, temperatures do not decrease over SH midlatitudes during midwinter, in spite of large ozone losses. These data furthermore show globally coherent ozone and temperature perturbations associated with both QBO and ENSO variations; a new result here show large total ozone anomalies in middle-to-high latitudes of both hemispheres associated with ENSO events. Residuals from the ozone and temperature time series (defined as the deseasonalized total minus the regression fits) show strong positive correlation in middle-to-high latitudes but weak correlations in the trop ics. Time periods following the volcanic eruptions of El Chichon and Pinatubo are clearly identified from the coupled signatures of decreased ozone and increased temperature, opposite to the positive ozone-temperature correlations observed at other times. The ratios of ozone to temperature anomalies derived here show quantitative signatures indicating that either radiative (trend, solar, and QBO) or dynamical (ENSO and residuals) processes are

  18. Natural changes in brain temperature underlie variations in song tempo during a mating behavior.

    PubMed

    Aronov, Dmitriy; Fee, Michale S

    2012-01-01

    The song of a male zebra finch is a stereotyped motor sequence whose tempo varies with social context--whether or not the song is directed at a female bird--as well as with the time of day. The neural mechanisms underlying these changes in tempo are unknown. Here we show that brain temperature recorded in freely behaving male finches exhibits a global increase in response to the presentation of a female bird. This increase strongly correlates with, and largely explains, the faster tempo of songs directed at a female compared to songs produced in social isolation. Furthermore, we find that the observed diurnal variations in song tempo are also explained by natural variations in brain temperature. Our findings suggest that brain temperature is an important variable that can influence the dynamics of activity in neural circuits, as well as the temporal features of behaviors that some of these circuits generate.

  19. Vertical and seasonal variations in temperature responses of leaf respiration in a Chamaecyparis obtusa canopy.

    PubMed

    Araki, Masatake G; Gyokusen, Koichiro; Kajimoto, Takuya

    2017-02-23

    Leaf respiration (R) is a major component of carbon balance in forest ecosystems. Clarifying the variability of leaf R within a canopy is essential for predicting the impact of global warming on forest productivity and the potential future function of the forest ecosystem as a carbon sink. We examined vertical and seasonal variations in short-term temperature responses of leaf R as well as environmental factors (light and mean air temperature) and physiological factors [leaf nitrogen (N), leaf mass per area (LMA), and shoot growth] in the canopy of a 10-year-old stand of hinoki cypress [Chamaecyparis obtusa (Sieb. et Zucc.) Endl.] in Kyushu, Japan. Leaf respiration rate adjusted to 20 °C (R20) exhibited evident vertical gradients in each season and was correlated with light, LMA and leaf N. In contrast, the temperature sensitivity of leaf R (Q10) did not vary vertically throughout the seasons. Seasonally, Q10 was higher in winter than in summer and was strongly negatively correlated to mean air temperature. A negative correlation of R20 with mean air temperature was also observed for each of the three canopy layers. These results clearly indicate that leaf R was able to adjust to seasonal changes in ambient temperature under field conditions and down-regulate during warmer periods. We also found that the degree of thermal acclimation did not vary with canopy position. Overall, our results suggest that vertical and seasonal variations in temperature responses of leaf R within a hinoki cypress canopy could be predicted by relatively simple parameters (light and temperature). There was an exception of extremely high R20 values in April that may have been due to the onset of shoot growth in spring. Understanding thermal acclimation and variations in leaf R within forest canopies will improve global terrestrial carbon cycle models. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Does Amazonian deforestation cause global effects on temperature and precipitation?

    NASA Astrophysics Data System (ADS)

    Lorenz, Ruth; Pitman, Andy J.; Sisson, Scott A.

    2015-04-01

    Some studies find global effects from Amazonian deforestation whereas others do not. The differences between the different studies are many, ranging from different resolution, quality of the control climate, land-atmosphere coupling to the statistical testing. The local effects are quite clear, generally deforestation leads to decreases in precipitation and increasing temperatures. The remaining question is whether some of these effects spread over to other regions of the globe. We investigate the following questions using the Australian Community Climate Earth System Simulator (ACCESS) with prescribed sea surface temperatures: (1) Which statistical method(s) should be used to investigate global effects from local deforestation? (2) Does Amazonian deforestation cause statistically significant global effects in temperature and precipitation in ACCESS? (3) If yes, how large does the perturbation need to be to trigger global scale effects? Our results show that a modified t-test, taking into account the autocorrelation in the time series, in addition with a test for field significance, taking into account the spatial correlation in the fields, can be a computationally efficient statistical method. In ACCESS, deforestation in Amazonia does not lead to statistically significant global effects, even if the perturbed area covers all of Amazonia. However, if we use simple statistical methods, significant teleconnections appear to emerge from the simulations but these are expressions of internal model variability. Further research will show if these results change if a slab-ocean is used instead of prescribed sea surface temperatures.

  1. A Data Gap Analysis and Efforts Towards Improving NOAA's Global Surface Temperature

    NASA Astrophysics Data System (ADS)

    Zhang, H. M.; Wuertz, D.; Nickl, E.; Banzon, P. V. F.; Gleason, B.; Huang, B.; Lawrimore, J. H.; Menne, M. J.; Rennie, J.; Thorne, P.; Williams, C. N., Jr.

    2014-12-01

    Estimates of global surface temperature trends from some sources have indicated slowing in the rate of warming over the last decade compared to the long-term warming trend since the industrial revolution. It has been debated whether this recent slowdown is due to natural variability or a missed signal due to gaps in the global observation networks, particularly over the Arctic Region. To examine this more closely, we quantify the impact of data gaps on the global surface temperature trends in several regions of the world (e.g. Polar Regions and the Continents of African and South America), using major global datasets including NOAA's Merged Land-Ocean Temperature dataset (NOAATemp). We also study the impact of the greater observational coverage in a recently released global temperature data set as part of the International Surface Temperature Initiative (ISTI), and analyze the spatial-temporal variation patterns of the homogenization effect on NOAATemp. A summary of the progress and challenges in filling in grid boxes where observations are sparse over large areas are presented.

  2. Quantitative assessment of drivers of recent global temperature variability: an information theoretic approach

    NASA Astrophysics Data System (ADS)

    Bhaskar, Ankush; Ramesh, Durbha Sai; Vichare, Geeta; Koganti, Triven; Gurubaran, S.

    2017-02-01

    Identification and quantification of possible drivers of recent global temperature variability remains a challenging task. This important issue is addressed adopting a non-parametric information theory technique, the Transfer Entropy and its normalized variant. It distinctly quantifies actual information exchanged along with the directional flow of information between any two variables with no bearing on their common history or inputs, unlike correlation, mutual information etc. Measurements of greenhouse gases: CO2 , CH4 and N2O; volcanic aerosols; solar activity: UV radiation, total solar irradiance (TSI) and cosmic ray flux (CR); El Niño Southern Oscillation (ENSO) and Global Mean Temperature Anomaly (GMTA) made during 1984-2005 are utilized to distinguish driving and responding signals of global temperature variability. Estimates of their relative contributions reveal that CO2 ({˜ } 24 % ), CH4 ({˜ } 19 % ) and volcanic aerosols ({˜ }23 % ) are the primary contributors to the observed variations in GMTA. While, UV ({˜ } 9 % ) and ENSO ({˜ } 12 % ) act as secondary drivers of variations in the GMTA, the remaining play a marginal role in the observed recent global temperature variability. Interestingly, ENSO and GMTA mutually drive each other at varied time lags. This study assists future modelling efforts in climate science.

  3. Comparative terrestrial planet thermospheres 2. Solar cycle variation of global structure and winds at equinox

    NASA Astrophysics Data System (ADS)

    Bougher, S. W.; Engel, S.; Roble, R. G.; Foster, B.

    1999-07-01

    The present maturity of available planetary databases and modeling capabilities now permits us to extend the comparison of terrestrial planetary thermospheres beyond the limited capability of one-dimensional models to global multidimensional models [e.g., Bougher and Roble, 1997]. This effort focuses upon the comparison of the solar cycle responses of the thermospheres of Venus, Earth, and Mars using three-dimensional global models that couple the energetics, dynamics, and neutral-ion composition above ~100 km for each planet. Standard solar EUV and UV fluxes are adopted for use in these simulations. The Venus, Earth, and Mars Thermosphere General Circulation Models (TGCMs) each share a common formulation scheme and development heritage making use of the computing facilities of the National Center for Atmospheric Research. The motivation of this research is not only to simulate the observed responses of these individual planets to solar EUV/UV flux variations but also to understand the relative importance of common processes that regulate this unique behavior. The role of O-CO2 enhanced 15-μm cooling is investigated in the context of global dynamics and its effect on atomic-O distributions. It is found that CO2 cooling is an effective thermostat for control of the Venus dayside temperatures, while Mars and Earth are only moderately affected. By contrast, the role of global dynamics in controlling temperature distributions is most pronounced for Mars and the Venus nightside but negligible for Earth. The net effect of these radiative and dynamical processes is to determine that Venus and Mars thermospheres respond rather quickly to solar flux variations (much less than an Earth day), while the Earth thermosphere is more sluggish in its behavior. This work confirms the relative importance of CO2 cooling in the Earth's lower thermosphere. Furthermore, the value of the CO2-O deactivation rate near 300 K is rather well constrained by these planetary comparisons.

  4. A temperature probe survey on the Louisiana shelf: Effects of bottom-water temperature variations

    SciTech Connect

    Cathles, L.M. ); Nunns, A.G. )

    1991-01-01

    A survey of temperature gradients in the uppermost sediments of the Louisiana continental shelf was done in 1983 by Gulf Oil Corporation, using a 5-m-long temperature probe. The survey covered 450 mi{sup 2}, with an average grid spacing of less than 1 mi. The purpose was to detect heat flow anomalies due to subsurface fluid flow. However, thermal perturbations due to seasonal variation of bottom-water temperature mask the temperature gradients due to geological heat flow. Bottom-water temperature variations similar to those recorded near the survey area in 1963-1965 explain most of the observed spatial and temporal changes in shallow temperature-depth profiles. The data set from this detailed survey has been donated to a publicly accessible scientific database, to spur research into heat flow measurement on continental shelves.

  5. Cloud Water Path Variation with Temperature over China

    NASA Astrophysics Data System (ADS)

    Li, X.; Guo, X.; Zhu, J.

    2009-12-01

    Cloud feedback has been one of the most concerned topics in climate change research. The insufficient understanding of cloud feedbacks is a major source of uncertainty in GCM simulations. With satellite cloud property data and reanalysis data, quantitative understanding of cloud feedback becomes possible. In this research, cloud water path (CWP) variation with temperature (Ta) is investigated and the research area locates in China. CWP, cloud top temperature (CTT) and cloud top pressure (CTP) data are from ISCCP (International Satellite Cloud Climatology Project). Ta data are from ERA-40. Data are collected from 1984 to 2001. According to regional climatic features, the analyses are carried out in five different areas. We use the same method, which was used by Tselioudis to analyze the relation between cloud optical thickness and temperature, to calculate the Logarithmic derivative of CWP with temperature. CWP is sampled from clouds with tops in the 680-800 mb range and Ta is the mean temperature of the 680-800 mb. According to the analysis over China, to the south of 35°N, CWP increased with Ta. But to the north of 35°N, CWP decreases with Ta in the temperature interval of 263-273K and increases with Ta in the other temperature intervals in the Northeastern China. The CWP decreases with Ta in the Northwestern China. The different seasonal patterns of CWP variation with temperature are also found. In the Northwestern China, CWP decreases with Ta in different seasons. In the Northeastern China, CWP decreases with Ta in spring and fall. CWP increases with Ta in the Southeastern China except summer. In the Southwestern China, CWP decreased with Ta in summer and fall. In the Tibetan Plateau CWP increased with Ta excluding winter.

  6. Summer temperature variation and implications for juvenile Atlantic salmon

    USGS Publications Warehouse

    Mather, M. E.; Parrish, D.L.; Campbell, C.A.; McMenemy, J.R.; Smith, Joseph M.

    2008-01-01

    Temperature is important to fish in determining their geographic distribution. For cool- and cold-water fish, thermal regimes are especially critical at the southern end of a species' range. Although temperature is an easy variable to measure, biological interpretation is difficult. Thus, how to determine what temperatures are meaningful to fish in the field is a challenge. Herein, we used the Connecticut River as a model system and Atlantic salmon (Salmo salar) as a model species with which to assess the effects of summer temperatures on the density of age 0 parr. Specifically, we asked: (1) What are the spatial and temporal temperature patterns in the Connecticut River during summer? (2) What metrics might detect effects of high temperatures? and (3) How is temperature variability related to density of Atlantic salmon during their first summer? Although the most southern site was the warmest, some northern sites were also warm, and some southern sites were moderately cool. This suggests localized, within basin variation in temperature. Daily and hourly means showed extreme values not apparent in the seasonal means. We observed significant relationships between age 0 parr density and days at potentially stressful, warm temperatures (???23??C). Based on these results, we propose that useful field reference points need to incorporate the synergistic effect of other stressors that fish encounter in the field as well as the complexity associated with cycling temperatures and thermal refuges. Understanding the effects of temperature may aid conservation efforts for Atlantic salmon in the Connecticut River and other North Atlantic systems. ?? 2008 Springer Science+Business Media B.V.

  7. Geographic variation in the response of Culex pipiens life history traits to temperature.

    PubMed

    Ruybal, Jordan E; Kramer, Laura D; Kilpatrick, A Marm

    2016-02-29

    Climate change is predicted to alter the transmission of many vector-borne pathogens. The quantitative impact of climate change is usually estimated by measuring the temperature-performance relationships for a single population of vectors, and then mapping this relationship across a range of temperatures or locations. However, life history traits of different populations often differ significantly. Specifically, performance across a range of temperatures is likely to vary due to local adaptation to temperature and other factors. This variation can cause spatial variation in pathogen transmission and will influence the impact of climate change on the transmission of vector-borne pathogens. We quantified variation in life history traits for four populations of Culex pipiens (Linnaeus) mosquitoes. The populations were distributed along altitudinal and latitudinal gradients in the eastern United States that spanned ~3 °C in mean summer temperature, which is similar to the magnitude of global warming expected in the next 3-5 decades. We measured larval and adult survival, development rate, and biting rate at six temperatures between 16 and 35 °C, in a common garden experiment. Temperature had strong and consistent non-linear effects on all four life history traits for all four populations. Adult female development time decreased monotonically with increasing temperature, with the largest decrease at cold temperatures. Daily juvenile and adult female survival also decreased with increasing temperature, but the largest decrease occurred at higher temperatures. There was significant among-population variation in the thermal response curves for the four life history traits across the four populations, with larval survival, adult survival, and development rate varying up to 45, 79, and 84 % among populations, respectively. However, variation was not correlated with local temperatures and thus did not support the local thermal adaptation hypothesis. These results suggest

  8. Prenatal exposure to diurnal temperature variation and early childhood pneumonia.

    PubMed

    Zeng, Ji; Lu, Chan; Deng, Qihong

    2017-04-01

    Childhood pneumonia is one of the leading single causes of mortality and morbidity in children worldwide, but its etiology still remains unclear. We investigate the association between childhood pneumonia and exposure to diurnal temperature variation (DTV) in different timing windows. We conducted a prospective cohort study of 2,598 children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed by a questionnaire administered by the parents. Individual exposure to DTV during both prenatal and postnatal periods was estimated. Logic regression models was used to examine the association between childhood pneumonia and DTV exposure in terms of odds ratios (OR) and 95% confidence interval (CI). Lifetime prevalence of childhood pneumonia in preschool children in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal DTV exposure, with adjusted OR (95%CI) =1.19 (1.02-1.38), particularly during the second trimester. However, childhood pneumonia not associated with postnatal DTV exposure. Sensitivity analysis indicated that boys are more susceptible to the pneumonia risk of diurnal temperature variation than girls. We further observed that the prevalence of childhood pneumonia was decreased in recent years as DTV shrinked. Early childhood pneumonia was associated with prenatal exposure to the diurnal temperature variation (DTV) during pregnancy, particularly in the second trimester, which suggests fetal origin of childhood pneumonia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Morice, C. P.; Rayner, N. A.; Auchmann, R.; Bessembinder, J.; Bronnimann, S.; Brugnara, Y.; Conway, E. A.; Ghent, D.; Good, E.; Herring, K.; Kennedy, J.; Lindgren, F.; Madsen, K. S.; Merchant, C. J.; van der Schrier, G.; Stephens, A.; Tonboe, R. T.; Waterfall, A. M.; Mitchelson, J.; Woolway, I.

    2015-12-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. These relationships can be derived either empirically or with the help of a physical model.Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals would be used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods.We will present plans and progress along this road in the EUSTACE project (2015-June 2018), i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras.Information will also be given on how interested users can become

  10. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Rayner, Nick

    2017-04-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project: 1. providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; 2. identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; 3. estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; 4. using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

  11. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Ghent, D.; Rayner, N. A.

    2016-12-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project, i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

  12. Sensitivity of regional climate to global temperature and forcing

    NASA Astrophysics Data System (ADS)

    Tebaldi, Claudia; O'Neill, Brian; Lamarque, Jean-François

    2015-07-01

    The sensitivity of regional climate to global average radiative forcing and temperature change is important for setting global climate policy targets and designing scenarios. Setting effective policy targets requires an understanding of the consequences exceeding them, even by small amounts, and the effective design of sets of scenarios requires the knowledge of how different emissions, concentrations, or forcing need to be in order to produce substantial differences in climate outcomes. Using an extensive database of climate model simulations, we quantify how differences in global average quantities relate to differences in both the spatial extent and magnitude of climate outcomes at regional (250-1250 km) scales. We show that differences of about 0.3 °C in global average temperature are required to generate statistically significant changes in regional annual average temperature over more than half of the Earth’s land surface. A global difference of 0.8 °C is necessary to produce regional warming over half the land surface that is not only significant but reaches at least 1 °C. As much as 2.5 to 3 °C is required for a statistically significant change in regional annual average precipitation that is equally pervasive. Global average temperature change provides a better metric than radiative forcing for indicating differences in regional climate outcomes due to the path dependency of the effects of radiative forcing. For example, a difference in radiative forcing of 0.5 W m-2 can produce statistically significant differences in regional temperature over an area that ranges between 30% and 85% of the land surface, depending on the forcing pathway.

  13. Global genetic variations predict brain response to faces.

    PubMed

    Dickie, Erin W; Tahmasebi, Amir; French, Leon; Kovacevic, Natasa; Banaschewski, Tobias; Barker, Gareth J; Bokde, Arun; Büchel, Christian; Conrod, Patricia; Flor, Herta; Garavan, Hugh; Gallinat, Juergen; Gowland, Penny; Heinz, Andreas; Ittermann, Bernd; Lawrence, Claire; Mann, Karl; Martinot, Jean-Luc; Nees, Frauke; Nichols, Thomas; Lathrop, Mark; Loth, Eva; Pausova, Zdenka; Rietschel, Marcela; Smolka, Michal N; Ströhle, Andreas; Toro, Roberto; Schumann, Gunter; Paus, Tomáš

    2014-08-01

    Face expressions are a rich source of social signals. Here we estimated the proportion of phenotypic variance in the brain response to facial expressions explained by common genetic variance captured by ∼ 500,000 single nucleotide polymorphisms. Using genomic-relationship-matrix restricted maximum likelihood (GREML), we related this global genetic variance to that in the brain response to facial expressions, as assessed with functional magnetic resonance imaging (fMRI) in a community-based sample of adolescents (n = 1,620). Brain response to facial expressions was measured in 25 regions constituting a face network, as defined previously. In 9 out of these 25 regions, common genetic variance explained a significant proportion of phenotypic variance (40-50%) in their response to ambiguous facial expressions; this was not the case for angry facial expressions. Across the network, the strength of the genotype-phenotype relationship varied as a function of the inter-individual variability in the number of functional connections possessed by a given region (R(2) = 0.38, p<0.001). Furthermore, this variability showed an inverted U relationship with both the number of observed connections (R2 = 0.48, p<0.001) and the magnitude of brain response (R(2) = 0.32, p<0.001). Thus, a significant proportion of the brain response to facial expressions is predicted by common genetic variance in a subset of regions constituting the face network. These regions show the highest inter-individual variability in the number of connections with other network nodes, suggesting that the genetic model captures variations across the adolescent brains in co-opting these regions into the face network.

  14. Global Genetic Variations Predict Brain Response to Faces

    PubMed Central

    Dickie, Erin W.; Tahmasebi, Amir; French, Leon; Kovacevic, Natasa; Banaschewski, Tobias; Barker, Gareth J.; Bokde, Arun; Büchel, Christian; Conrod, Patricia; Flor, Herta; Garavan, Hugh; Gallinat, Juergen; Gowland, Penny; Heinz, Andreas; Ittermann, Bernd; Lawrence, Claire; Mann, Karl; Martinot, Jean-Luc; Nees, Frauke; Nichols, Thomas; Lathrop, Mark; Loth, Eva; Pausova, Zdenka; Rietschel, Marcela; Smolka, Michal N.; Ströhle, Andreas; Toro, Roberto; Schumann, Gunter; Paus, Tomáš

    2014-01-01

    Face expressions are a rich source of social signals. Here we estimated the proportion of phenotypic variance in the brain response to facial expressions explained by common genetic variance captured by ∼500,000 single nucleotide polymorphisms. Using genomic-relationship-matrix restricted maximum likelihood (GREML), we related this global genetic variance to that in the brain response to facial expressions, as assessed with functional magnetic resonance imaging (fMRI) in a community-based sample of adolescents (n = 1,620). Brain response to facial expressions was measured in 25 regions constituting a face network, as defined previously. In 9 out of these 25 regions, common genetic variance explained a significant proportion of phenotypic variance (40–50%) in their response to ambiguous facial expressions; this was not the case for angry facial expressions. Across the network, the strength of the genotype-phenotype relationship varied as a function of the inter-individual variability in the number of functional connections possessed by a given region (R2 = 0.38, p<0.001). Furthermore, this variability showed an inverted U relationship with both the number of observed connections (R2 = 0.48, p<0.001) and the magnitude of brain response (R2 = 0.32, p<0.001). Thus, a significant proportion of the brain response to facial expressions is predicted by common genetic variance in a subset of regions constituting the face network. These regions show the highest inter-individual variability in the number of connections with other network nodes, suggesting that the genetic model captures variations across the adolescent brains in co-opting these regions into the face network. PMID:25122193

  15. Compensatory water effects link yearly global land CO2 sink changes to temperature

    NASA Astrophysics Data System (ADS)

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R.; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K.; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  16. Compensatory water effects link yearly global land CO2 sink changes to temperature.

    PubMed

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-26

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  17. Compensatory Water Effects Link Yearly Global Land CO2 Sink Changes to Temperature

    NASA Technical Reports Server (NTRS)

    Jung, Martin; Reichstein, Markus; Tramontana, Gianluca; Viovy, Nicolas; Schwalm, Christopher R.; Wang, Ying-Ping; Weber, Ulrich; Weber, Ulrich; Zaehle, Soenke; Zeng, Ning; hide

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems13. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales314. Here we use empirical models based on eddy covariance data15 and process-based models16,17 to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance36,9,11,12,14. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  18. Effect of gravity wave temperature variations on homogeneous ice nucleation

    NASA Astrophysics Data System (ADS)

    Dinh, Tra; Podglajen, Aurélien; Hertzog, Albert; Legras, Bernard; Plougonven, Riwal

    2015-04-01

    Observations of cirrus clouds in the tropical tropopause layer (TTL) have shown various ice number concentrations (INC) (e.g., Jensen et al. 2013), which has lead to a puzzle regarding their formation. In particular, the frequently observed low numbers of ice crystals seemed hard to reconcile with homogeneous nucleation knowing the ubuquity of gravity waves with vertical velocity of the order of 0.1 m/s. Using artificial time series, Spichtinger and Krämer (2013) have illustrated that the variation of vertical velocity during a nucleation event could terminate it and limit the INC. However, their study was limited to constructed temperature time series. Here, we carry out numerical simulations of homogeneous ice nucleation forced by temperature time series data collected by isopycnic balloon flights near the tropical tropopause. The balloons collected data at high frequency (30 s), so gravity wave signals are well resolved in the temperature time series. With the observed temperature time series, the numerical simulations with homogeneous freezing show a full range of ice number concentrations (INC) as previously observed in the tropical upper troposphere. The simulations confirm that the dynamical time scale of temperature variations (as seen from observations) can be shorter than the nucleation time scale. They show the existence of two regimes for homogeneous ice nucleation : one limited by the depletion of water vapor by the nucleated ice crystals (those we name vapor events) and one limited by the reincrease of temperature after its initial decrease (temperature events). Low INC may thus be obtained for temperature events when the gravity wave perturbations produce a non-persistent cooling rate (even with large magnitude) such that the absolute change in temperature remains small during nucleation. This result for temperature events is explained analytically by a dependence of the INC on the absolute drop in temperature (and not on the cooling rate). This

  19. Unexpected and Unexplained Surface Temperature Variations on Mimas

    NASA Astrophysics Data System (ADS)

    Howett, C.; Spencer, J. R.; Pearl, J. C.; Hurford, T. A.; Segura, M.; Cassini Cirs Team

    2010-12-01

    Until recently it was thought one of the most interesting things about Mimas, Saturn’s innermost classical icy moon, was its resemblance to Star Wars’ Death Star. However, a bizarre pattern of daytime surface temperatures was observed on Mimas using data obtained by Cassini’s Composite Infrared Spectrometer (CIRS) in February 2010. The observations were taken during Cassini’s closest ever encounter with Mimas (<10,000 km) and cover the daytime anti-Saturn hemisphere centered on longitude ~145° W. Instead of surface temperatures smoothly increasing throughout the morning and early afternoon, then cooling in the evening, as expected, a sharp V-shaped boundary is observed separating cooler midday and afternoon temperatures (~77 K) on the leading side from warmer morning temperatures (~92 K) on the trailing side. The boundary’s apex is centered at equatorial latitudes near the anti-Saturn point and extends to low north and south latitudes on the trailing side. Subtle differences in the surface colors have been observed that are roughly spatially correlated with the observed extent of the temperature anomaly, with the cooler regions tending to be bluer (Schenk et al., Submitted). However, visible-wavelength albedo is similar in the two regions, so albedo variations are probably not directly responsible for the thermal anomaly. It is more likely that thermal inertia variations produce the anomaly, with thermal inertia being unusually high in the region with anomalously low daytime temperatures. Comparison of the February 2010 CIRS data to previous lower spatial resolution data taken at different local times tentatively confirm that the cooler regions do indeed display higher thermal inertias. Bombardment of the surface by high energy electrons from Saturn’s radiation belts has been proposed to explain the observed color variations (Schenk et al., Submitted). Electrons above ~1 MeV preferentially impact Mimas’ leading hemisphere at low latitudes where they

  20. Seasonal variations in the subauroral electron temperature enhancement

    NASA Technical Reports Server (NTRS)

    Fok, M.-C.; Kozyra, J. U.; Warren, M. F.; Brace, L. H.

    1991-01-01

    A statistical study of the seasonal variations of the subauroral electron temperature enhancement was undertaken using data from the Langmuir probe experiment on the DE 2 satellite throughout most of the mission (1981-1982). In the winter hemisphere the nighttime background electron temperature is the highest and the magnitude of the peak Te responds most weakly to the geomagnetic activity. This behavior can be explained by seasonal trends in the nighttime downward heat flux due to conjugate photoelectrons. Moreover, model results indicate that a factor of about three increase in heat inflow during equinox relative to solstice is required to raise the electron temperature to a given level. This is a consequence of the higher electron densities at the Te peak near equinox. The Te peak occurs on field lines which thread the outer plasmasphere in the vicinity if the plasmapause and thus can be used as a tracer of the plasmapause position.

  1. Variation of the global electric circuit and Ionospheric potential in a general circulation model

    NASA Astrophysics Data System (ADS)

    Mareev, E. A.; Volodin, E. M.

    2014-12-01

    A general circulation model of the atmosphere and ocean INMCM4.0 (Institute of Numerical Mathematics Coupled Model) is used for modeling the global electric circuit short-time variability and long-term evolution. The ionospheric potential parameterization is proposed which takes into account quasi-stationary currents of electrified clouds (including thunderstorms) as principal contributors into the DC global circuit. The diurnal, seasonal, and interannual variations of the ionospheric potential (IP) are modeled and compared with available data. Numerical simulations suggest that the IP decreases in the mean with the global warming due to increasing greenhouse gas emission (by about 10% during the 21st century if the Representative Concentration Pathway 8.5 Wm-2 scenario is assumed). At the same time the lightning flash rate increases with global warming by about 5 fl/s per degree. Interannual IP variability is low and does not exceed 1% of the mean value, being tightly correlated with the mean sea surface temperature in the Pacific Ocean (El Niño area).

  2. [Health consequences of environmental temperature and climate variations].

    PubMed

    Swynghedauw, Bernard

    2012-01-01

    Recent climate change is a consequence of the greenhouse effect and human activity, and is directly responsible for extreme events such as heatwaves (see report of the French Académie des Sciences). Human thermoregulation depends more on behavior than on biology Air conditioning and building structure play an essential role. The 2003 heatwave was not a unique event. Preventive measures reduced mortality during subsequent heatwaves. Most deaths were due to heat stroke associated with dehydration. During strenuous exercise, especially during military training, heat stroke requires specific treatment. Temperature/ global mortality and temperature/cardiovascular mortality curves are both U-shaped. Usually, global mortality increases winter and is linked to temperature. During summer, global mortality increases only when heatwaves occur. Climate change participates in the spread of infectious diseases. Nevertheless, in continental France, for the moment, climate change is not a major factor in the incidence of infectious diseases, despite the fact that several bacteria, viruses and vectors are temperature-sensitive. The situation in Reunion, French Polynesia and French Departments of America is more complicated, due to their geographic heterogeneity. Some areas are more exposed to the climatic risk and could act as a gateway for new infections and mutations. The dramatic loss of biodiversity is partly a consequence of climate change. It increases the transmissibility of some pathogens and can also potentially lead to an increase in autoimmune diseases and obesity. Climate change plays a important role in allergic diseases, through changes in the diffusion and composition of pollens. These modifications are being monitored by several observatories. Six different veterinary diseases, including several zoonoses, are of particular concern.

  3. The Atlanto-Pacific multidecade oscillation and its imprint on the global temperature record

    NASA Astrophysics Data System (ADS)

    Nagy, Melinda; Petrovay, Kristóf; Erdélyi, Robert

    2017-03-01

    Results from a multiregression analysis of the global and sea surface temperature anomalies for the period 1950-2011 are presented where among the independent variables multidecade oscillation signals over various oceanic areas are included. These indices are defined in analogy with the Atlantic Multidecadal Oscillation (AMO) index. Unexpectedly we find that a strong multidecade oscillation signal echoing the AMO is also present in the Western and Northwestern Pacific region. The results indicate that naturally induced climate variations seem to be dominated by two internal variability modes of the ocean-atmosphere system: AMO and El Niño Southern Oscillation, with a marked geographical dichotomy in their respective areas of dominance. As the AMO index is directly derived from SST data the finding that the AMO signal is present on a large fraction of the global oceanic surface casts doubt on its use as an independent explanatory variable in regression analyses of the global surface temperature anomalies.

  4. The temperature variations of sinking rivers in karst

    NASA Astrophysics Data System (ADS)

    Gabrovsek, F.; Turk, J.

    2009-04-01

    Karst aquifers are often fed by concentrated inputs such as sinking streams originating from the adjacent non-karstic areas. When entering an underground conduit system a stream experiences new flow regime which can be much different from the surface one. An important parameter which also reflects the new environment is the temperature. The temperature of surface streams is a result of surface climatic and hydrological conditions, such as a stream discharge, air & ground temperatures and the solar radiation. These impose stream temperature variations of different amplitudes and frequencies. Water temperatures follow seasonal and diurnal cycles, latter being superimposed on the former. Along the underground course, a river exchanges heat with the surrounding karst massif. The conductive heat exchange between the stream water, the hyporheic zone and the cave walls become more important, whilst radiative heat fluxes is to a greater extent diminished. We present analyses of the long term continuous monitoring of temperature and discharge of sinking river Pivka in Postojnska jama, Slovenia. To analyse and interpret the results we applied a simple finite difference model assuming heat exchange between river, hyporheic zone and surrounding rock mass.

  5. Global atmospheric temperature anomaly monitoring with passive microwave radiometers

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1990-01-01

    The potential of microwave sounding units (MSU) for augmenting the surface-based thermometer record by providing a measurement representing a significant depth of the troposphere is considered. These radiometers measure the thermal emission by molecular oxygen in the atmosphere at different spectral intervals in the oxygen absorption complex near 60 GHz. Brightness temperature variations measured by NOAA-6 and NOAA-7 MSUs during a near-two year period are analyzed and compared with monthly averaged surface air temperature data. It is demonstrated that MSUs, while of limited use for vertical profiling of the atmosphere, provide stable measurements of vertically average atmospheric temperatures, centered at a constant pressure level.

  6. Rice yields decline with higher night temperature from global warming

    PubMed Central

    Peng, Shaobing; Huang, Jianliang; Sheehy, John E.; Laza, Rebecca C.; Visperas, Romeo M.; Zhong, Xuhua; Centeno, Grace S.; Khush, Gurdev S.; Cassman, Kenneth G.

    2004-01-01

    The impact of projected global warming on crop yields has been evaluated by indirect methods using simulation models. Direct studies on the effects of observed climate change on crop growth and yield could provide more accurate information for assessing the impact of climate change on crop production. We analyzed weather data at the International Rice Research Institute Farm from 1979 to 2003 to examine temperature trends and the relationship between rice yield and temperature by using data from irrigated field experiments conducted at the International Rice Research Institute Farm from 1992 to 2003. Here we report that annual mean maximum and minimum temperatures have increased by 0.35°C and 1.13°C, respectively, for the period 1979–2003 and a close linkage between rice grain yield and mean minimum temperature during the dry cropping season (January to April). Grain yield declined by 10% for each 1°C increase in growing-season minimum temperature in the dry season, whereas the effect of maximum temperature on crop yield was insignificant. This report provides a direct evidence of decreased rice yields from increased nighttime temperature associated with global warming. PMID:15226500

  7. Active Volcanism on Io: Global Distribution and Variations in Activity

    USGS Publications Warehouse

    Lopes-Gautier, R.; McEwen, A.S.; Smythe, W.B.; Geissler, P.E.; Kamp, L.; Davies, A.G.; Spencer, J.R.; Keszthelyi, L.; Carlson, R.; Leader, F.E.; Mehlman, R.; Soderblom, L.

    1999-01-01

    Io's volcanic activity has been monitored by instruments aboard the Galileo spacecraft since June 28, 1996. We present results from observations by the near-infrared mapping spectrometer (NIMS) for the first 10 orbits of Galileo, correlate them with results from the Solid State Imaging System (SSI) and from groundbased observations, and compare them to what was known about Io's volcanic activity from observations made during the two Voyager flybys in 1979. A total of 61 active volcanic centers have been identified from Voyager, groundbased, and Galileo observations. Of these, 41 are hot spots detected by NIMS and/or SSI. Another 25 locations were identified as possible active volcanic centers, mostly on the basis of observed surface changes. Hot spots are correlated with surface colors, particularly dark and red deposits, and generally anti-correlated with white, SO2-rich areas. Surface features corresponding to the hot spots, mostly calderas or flows, were identified from Galileo and Voyager images. Hot spot temperatures obtained from both NIMS and SSI are consistent with silicate volcanism, which appears to be widespread on Io. Two types of hot spot activity are present: persistent-type activity, lasting from months to years, and sporadic events, which may represent either short-lived activity or low-level activity that occasionally flares up. Sporadic events are not often detected, but may make an important contribution to Io's heat flow and resurfacing. The distribution of active volcanic centers on the surface does not show any clear correlation with latitude, longitude, Voyager-derived global topography, or heat flow patterns predicted by the asthenosphere and deep mantle tidal dissipation models. However, persistent hot spots and active plumes are concentrated toward lower latitudes, and this distribution favors the asthenosphere rather than the deep mantle tidal dissipation model. ?? 1999 Academic Press.

  8. Variation in Yield Responses to Elevated CO2 and a Brief High Temperature Treatment in Quinoa

    PubMed Central

    Bunce, James A.

    2017-01-01

    Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient”) and 600 (“elevated”) μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control”) temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures) for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control) or increased (1.70 × control) seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined. PMID:28678208

  9. Spatial patterns of historical temperature variability: Global correlations using spectral and wavelet techniques

    SciTech Connect

    Park, J.

    1995-12-31

    In order to assess man`s impact on global climate, we need to understand natural climate variability more fully. Using 100 years of global temperature data, we have developed time-series methods that identify coherent spatio-temporal {open_quotes}modes{close_quotes} of temperature variability e.g., El Nino-Southern Oscillation (ENSO) cycles. Methods based on multiple-taper spectral analysis estimate the correlated temperature variability within narrow frequency bands. Methods based on a multiple wavelet analysis identify short-term global temperature {open_quotes}events{close_quotes} on a range of time scales. We assess the statistical significance of narrow-band and event correlations from Monte Carlo confidence limits, which are derived from stochastic variations of uncorrelated white-noise time series. Significant patterns of variability with 2.8 to 5.7 year duration exhibit the characteristic ENSO pattern: warming in the tropics, followed by temperature excursions in middle latitudes. An interdecadal mode (15-18 years) appears to represent long-term ENSO variability, an interpretation supported by the persistence of warm Pacific Ocean surface water in the decade after the large 1982-3 El Nino episode. The interdecadal mode appears to explain much of the anomalous global warmth of the 1980s. North Atlantic variability dominates quasi-biennial (2.2 years) and decadal (7-12 years) modes.

  10. Diurnal variations of Titan's surface temperatures from Cassini - CIRS observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Samuelson, R. E.; Irwin, P. G. J.; Flasar, F. M.

    2010-04-01

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 micron (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the instrument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature profile by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface.

  11. Variability in the Atmosphere-Ocean System and Global Change: Insights via Sea Surface Temperature Analysis

    NASA Astrophysics Data System (ADS)

    Dickey, J. O.; de Viron, O.; Marcus, S. L.

    2003-12-01

    We have extended an earlier study [Dickey et al., GRL, 2003] of the sea surface temperature (SST) field to longer time span (1870 to 2002), using the newly available Global Sea Surface Temperature (HadISST 1.1), a set of SST data in monthly 1 degree area grids. In the previous study, poleward propagating atmospheric zonal wind anomalies were observed, originating at the equator and penetrating to high latitudes in both hemispheres on interannual, decadal and longer timescales. These patterns were shown to be linked to complementary oscillations in the sea surface temperature (SST) field. Results from these extended analyses will be presented and the increasing intensity of these interannual, decadal and multi-decadal variations will be examined for possible indications of Global Warming.

  12. Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; He, Nianpeng

    2017-04-01

    How to assess the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition and its regional variation with high accuracy is one of the largest uncertainties in determining the intensity and direction of the global carbon (C) cycle in response to climate change. In this study, we collected a series of soils from 22 forest sites and 30 grassland sites across China to explore regional variation in Q10 and its underlying mechanisms. We conducted a novel incubation experiment with periodically changing temperature (5-30 °C), while continuously measuring soil microbial respiration rates. The results showed that Q10 varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q10 was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q10 of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q10 significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q10 across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q10. The general negative relationships between Q10 and substrate quality among all ecosystem types supported the C quality temperature (CQT) hypothesis at a large scale, which indicated that soils with low quality should have higher temperature sensitivity. Furthermore, alpine grasslands, which had the highest Q10, were predicted to be more sensitive to climate change under the scenario of global warming.

  13. Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands.

    PubMed

    Liu, Yuan; He, Nianpeng; Zhu, Jianxing; Xu, Li; Yu, Guirui; Niu, Shuli; Sun, Xiaomin; Wen, Xuefa

    2017-01-05

    How to assess the temperature sensitivity (Q10 ) of soil organic matter (SOM) decomposition and its regional variation with high accuracy is one of the largest uncertainties in determining the intensity and direction of the global carbon (C) cycle in response to climate change. In this study, we collected a series of soils from 22 forest sites and 30 grassland sites across China to explore regional variation in Q10 and its underlying mechanisms. We conducted a novel incubation experiment with periodically changing temperature (5-30 °C), while continuously measuring soil microbial respiration rates. The results showed that Q10 varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q10 was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q10 of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q10 significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q10 across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q10 . The general negative relationships between Q10 and substrate quality among all ecosystem types supported the C quality temperature (CQT) hypothesis at a large scale, which indicated that soils with low quality should have higher temperature sensitivity. Furthermore, alpine grasslands, which had the highest Q10 , were predicted to be more sensitive to climate change under the scenario of global warming.

  14. Solar variations and their influence on trends in upper stratospheric ozone and temperature

    SciTech Connect

    Wuebbles, D.J.; Kinnison, D.E. ); Lean, J.L. . E.O. Hulburt Center for Space Research)

    1990-10-01

    Over the past decade, knowledge of the magnitude and temporal structure of the variations in the sun's ultraviolet irradiance has increased steadily. A number of theoretical modeling studies have shown that changes in the solar ultraviolet flux during the 11-year solar cycle can have a significant effect on stratospheric ozone concentrations. With the exception of Brasseur et al., who examined a very broad range of solar flux variations, all of these studies assumed much larger changes in the ultraviolet flux than measurements now indicate. These studies either calculated the steady-state effect at solar maximum and solar minimum or assumed sinusoidal variations in the solar flux changes with time. It is now possible to narrow the uncertainty range of the expected effects on upper stratospheric ozone and temperature resulting from the 11-year solar cycle. A more accurate representation of the solar flux changes with time is used in this analysis, as compared to previous published studies. This study also evaluates the relative roles of solar flux variations and increasing concentrations of long-lived trace gases in determining the observed trends in upper stratospheric ozone and temperature. The LLNL two-dimensional chemical-radiative-transport model of the global atmosphere is used to evaluate the combined effects on the stratosphere from changes in solar ultraviolet irradiances and trace gas concentrations over the last several decades. Derived trends in upper stratospheric ozone concentrations and temperature are then compared with available analyses of ground-based and satellite measurements over this time period.

  15. Temperature-associated increases in the global soil respiration record

    SciTech Connect

    Bond-Lamberty, Benjamin; Thomson, Allison M.

    2010-03-25

    Soil respiration (RS), the flux of CO2 from the soil surface to the atmosphere, comprises the second-largest terrestrial carbon flux, but its dynamics are incompletely understood, and the global flux remains poorly constrained. Ecosystem warming experiments, modelling analyses, and biokinetics all suggest that RS should change with climate. This has been difficult to confirm observationally because of the high spatial variability of RS, inaccessibility of the soil medium, and inability of remote sensing instruments to measure large-scale RS fluxes. Given these constraints, is it possible to discern climate-driven changes in regional or global RS fluxes in the extant four-decade record of RS chamber measurements? Here we use a database of worldwide RS observations, matched with high-resolution historical climate data, to show a previously unknown temporal trend in the RS record after accounting for mean annual climate, leaf area, nitrogen deposition, and changes in CO2 measurement technique. Air temperature anomaly (deviation from the 1961-1990 mean) is significantly and positively correlated with changes in RS fluxes; both temperature and precipitation anomalies exert effects in specific biomes. We estimate that the current (2008) annual global RS flux is 98±12 Pg and has increased 0.1 Pg yr-1 over the last 20 years, implying a global RS temperature response (Q10) of 1.5. An increasing global RS flux does not necessarily constitute a positive feedback loop to the atmosphere; nonetheless, the available data are consistent with an acceleration of the terrestrial carbon cycle in response to global climate change.

  16. Cultural Variations in Global versus Local Processing: A Developmental Perspective

    ERIC Educational Resources Information Center

    Oishi, Shigehiro; Jaswal, Vikram K.; Lillard, Angeline S.; Mizokawa, Ai; Hitokoto, Hidefumi; Tsutsui, Yoshiro

    2014-01-01

    We conducted 3 studies to explore cultural differences in global versus local processing and their developmental trajectories. In Study 1 ("N" = 363), we found that Japanese college students were less globally oriented in their processing than American or Argentine participants. We replicated this effect in Study 2 ("N" =…

  17. Cultural Variations in Global versus Local Processing: A Developmental Perspective

    ERIC Educational Resources Information Center

    Oishi, Shigehiro; Jaswal, Vikram K.; Lillard, Angeline S.; Mizokawa, Ai; Hitokoto, Hidefumi; Tsutsui, Yoshiro

    2014-01-01

    We conducted 3 studies to explore cultural differences in global versus local processing and their developmental trajectories. In Study 1 ("N" = 363), we found that Japanese college students were less globally oriented in their processing than American or Argentine participants. We replicated this effect in Study 2 ("N" =…

  18. A global thermospheric model based on mass spectrometer and incoherent scatter data MSIS. I - N2 density and temperature

    NASA Technical Reports Server (NTRS)

    Hedin, A. E.; Reber, C. A.; Newton, G. P.; Spencer, N. W.; Salah, J. E.; Evans, J. V.; Kayser, D. C.; Alcayde, D.; Bauer, P.; Cogger, L.

    1977-01-01

    Measurements of neutral nitrogen density from mass spectrometers on five satellites (AE-B, Ogo 6, San Marco 3, Aeros A, and AE-C) and neutral temperatures inferred from incoherent scatter measurements at four ground stations are combined to produce a model of thermospheric neutral temperatures and nitrogen densities similar to the Ogo 6 empirical model (Hedin et al., 1974). This global model is designated MSIS (mass spectrometer and incoherent scatter). The global average temperature, the annual temperature variation, lower bound density, and lower bound temperature are discussed. The data set covers the time period from the end of 1965 to mid-1975 and also a wide range of solar activities. Diurnal and semidiurnal variations in lower bound density and temperature are considered, as is magnetic activity.

  19. A global thermospheric model based on mass spectrometer and incoherent scatter data MSIS. I - N2 density and temperature

    NASA Technical Reports Server (NTRS)

    Hedin, A. E.; Reber, C. A.; Newton, G. P.; Spencer, N. W.; Salah, J. E.; Evans, J. V.; Kayser, D. C.; Alcayde, D.; Bauer, P.; Cogger, L.

    1977-01-01

    Measurements of neutral nitrogen density from mass spectrometers on five satellites (AE-B, Ogo 6, San Marco 3, Aeros A, and AE-C) and neutral temperatures inferred from incoherent scatter measurements at four ground stations are combined to produce a model of thermospheric neutral temperatures and nitrogen densities similar to the Ogo 6 empirical model (Hedin et al., 1974). This global model is designated MSIS (mass spectrometer and incoherent scatter). The global average temperature, the annual temperature variation, lower bound density, and lower bound temperature are discussed. The data set covers the time period from the end of 1965 to mid-1975 and also a wide range of solar activities. Diurnal and semidiurnal variations in lower bound density and temperature are considered, as is magnetic activity.

  20. Seasonal and interannual temperature variations in the tropical stratosphere

    SciTech Connect

    Reid, G.C.

    1994-09-20

    Temperature variations in the tropical lower and middle stratosphere are influenced by at least five distinct driving forces. These are (1) the mechanism of the regular seasonal cycle, (2) the quasi-biennial oscillation (QBO) in zonal winds, (3) the semiannual zonal wind oscillation (SAO) at higher levels, (4) El Nino-Southern Oscillation (ENSO) effects driven by the underlying troposphere, and (5) radiative effects, including volcanic aerosol heating. Radiosonde measurements of temperatures from a number of tropical stations, mostly in the western Pacific region, are used in this paper to examine the characteristic annual and interannual temperature variability in the stratosphere below the 10-hPa pressure level ({approximately} 31 km) over a time period of 17 years, chosen to eliminate or at least minimize the effect of volcanic eruptions. Both annual and interannual variations are found to show a fairly distinct transition between the lower and the middle stratosphere at about the 35-hPa level ({approximately} 23 km). The lower stratosphere, below this transition level, is strongly influenced by the ENSO cycle as well as by the QBO. The overall result of the interaction is to modulate the amplitude of the normal stratospheric seasonal cycle and to impose a biennial component on it, so that alternate seasonal cycles are stronger or weaker than normal. Additional modulation by the ENSO cycle occurs at its quasi-period of 3-5 years, giving rise to a complex net behavior. In the middle stratosphere above the transition level, there is no discernible ENSO influence, and departures from the regular semiannual seasonal cycle are dominated by the QBO. Recent ideas on the underlying physical mechanisms governing these variations are discussed, as is the relationship of the radiosonde measurements to recent satellite remote-sensing observations. 37 refs., 8 figs., 1 tab.

  1. Learn Locally, Act Globally: Learning Language from Variation Set Cues

    ERIC Educational Resources Information Center

    Onnis, Luca; Waterfall, Heidi R.; Edelman, Shimon

    2008-01-01

    Variation set structure--partial overlap of successive utterances in child-directed speech--has been shown to correlate with progress in children's acquisition of syntax. We demonstrate the benefits of variation set structure directly: in miniature artificial languages, arranging a certain proportion of utterances in a training corpus in variation…

  2. The Effects of Temperature on Political Violence: Global Evidence at the Subnational Level

    PubMed Central

    Bollfrass, Alexander; Shaver, Andrew

    2015-01-01

    A number of studies have demonstrated an empirical relationship between higher ambient temperatures and substate violence, which have been extrapolated to make predictions about the security implications of climate change. This literature rests on the untested assumption that the mechanism behind the temperature-conflict link is that disruption of agricultural production provokes local violence. Using a subnational-level dataset, this paper demonstrates that the relationship: (1) obtains globally, (2) exists at the substate level — provinces that experience positive temperature deviations see increased conflict; and (3) occurs even in regions without significant agricultural production. Diminished local farm output resulting from elevated temperatures is unlikely to account for the entire increase in substate violence. The findings encourage future research to identify additional mechanisms, including the possibility that a substantial portion of the variation is brought about by the well-documented direct effects of temperature on individuals' propensity for violence or through macroeconomic mechanisms such as food price shocks. PMID:25992616

  3. The effects of temperature on political violence: global evidence at the subnational level.

    PubMed

    Bollfrass, Alexander; Shaver, Andrew

    2015-01-01

    A number of studies have demonstrated an empirical relationship between higher ambient temperatures and substate violence, which have been extrapolated to make predictions about the security implications of climate change. This literature rests on the untested assumption that the mechanism behind the temperature-conflict link is that disruption of agricultural production provokes local violence. Using a subnational-level dataset, this paper demonstrates that the relationship: (1) obtains globally, (2) exists at the substate level--provinces that experience positive temperature deviations see increased conflict; and (3) occurs even in regions without significant agricultural production. Diminished local farm output resulting from elevated temperatures is unlikely to account for the entire increase in substate violence. The findings encourage future research to identify additional mechanisms, including the possibility that a substantial portion of the variation is brought about by the well-documented direct effects of temperature on individuals' propensity for violence or through macroeconomic mechanisms such as food price shocks.

  4. Decadal modulation of global surface temperature by internal climate variability

    NASA Astrophysics Data System (ADS)

    Dai, Aiguo; Fyfe, John C.; Xie, Shang-Ping; Dai, Xingang

    2015-06-01

    Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernible warming since about 2000, in sharp contrast to model simulations, which on average project strong warming. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific, intensifying trade winds, changes in El Niño activity, increasing volcanic activity and decreasing solar irradiance. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyse observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Interdecadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called `hiatus' period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from those associated with GHG-induced warming or aerosol-induced cooling. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.

  5. Decadal Modulation of Global Surface Temperature By Internal Climate Variability

    NASA Astrophysics Data System (ADS)

    Dai, A.; Fyfe, J. C.; Xie, S. P.; Dai, X.

    2014-12-01

    Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernable warming since about 2000, in sharp contrast to model simulations which on average project strong warming. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific, intensifying trade winds, changes in El Niño activity, increasing volcanic activity and decreasing solar irradiance. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyze observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Inter-decadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land since 1920. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called "hiatus" period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from GHG-induced warming. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.

  6. Studying Stratospheric Temperature Variation with Cosmic Ray Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohang; He, Xiaochun

    2015-04-01

    The long term stratospheric cooling in recent decades is believed to be equally important as surface warming as evidence of influences of human activities on the climate system. Un- fortunatly, there are some discrepancies among different measurements of stratospheric tem- peratures, which could be partially caused by the limitations of the measurement techniques. It has been known for decades that cosmic ray muon flux is sensitive to stratospheric temperature change. Dorman proposed that this effect could be used to probe the tempera- ture variations in the stratophere. In this talk, a method for reconstructing stratospheric temperature will be discussed. We verify this method by comparing the stratospheric tem- perature measured by radiosonde with the ones derived from cosmic ray measurement at multiple locations around the globe.

  7. Evidence for Solar-Cycle Forcing and Secular Variation in the Armagh Observatory Temperature Record

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1998-01-01

    A prominent feature of previous long-term temperature studies has been the appearance of warming since the 1880s, this often being taken as evidence for anthropogenic-induced global warming. In this investigation, the long-term, annual, mean temperature record (1844-1992) of the Armagh Observatory (Armagh, North Ireland), a set of temperature data based on maximum and minimum thermometers that predates the 1880s and correlates well with northern hemispheric and global standards, is examined for evidence of systematic variation, in particular, as related to solar-cycle forcing and secular variation. Indeed, both appear to be embedded within the Armagh data. Removal of these effects, each contributing about 8% to the overall reduction in variance, yields residuals that are randomly distributed. Application of the 10-year moving average to the residuals, furthermore, strongly suggests that the behavior of the residuals is episodic, inferring that (for extended periods of time) temperatures at Armagh sometimes were warmer or cooler (than expected), while at other times they were stable. Comparison of cyclic averages of annual mean temperatures against the lengths of the associated Hale cycles (i.e., the length of two, sequentially numbered, even-odd sunspot cycle pairs) strongly suggests that the temperatures correlate inversely (r = -0.886 at less than 2% level of significance) against the length of the associated Hale cycle. Because sunspot cycle 22 ended in 1996, the present Hale cycle probably will be shorter than average, implying that temperatures at Armagh over this Hale cycle will be warmer (about 9.31 q 0.23 C at the 90% confidence level) than average (= 9.00 C).

  8. Upper temperature limits of tropical marine ectotherms: global warming implications.

    PubMed

    Nguyen, Khanh Dung T; Morley, Simon A; Lai, Chien-Houng; Clark, Melody S; Tan, Koh Siang; Bates, Amanda E; Peck, Lloyd S

    2011-01-01

    Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour(-1), the upper lethal temperature range of intertidal ectotherms was 41-52°C, but this range was narrower and reduced to 37-41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2-3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming.

  9. Upper Temperature Limits of Tropical Marine Ectotherms: Global Warming Implications

    PubMed Central

    Nguyen, Khanh Dung T.; Morley, Simon A.; Lai, Chien-Houng; Clark, Melody S.; Tan, Koh Siang; Bates, Amanda E.; Peck, Lloyd S.

    2011-01-01

    Animal physiology, ecology and evolution are affected by temperature and it is expected that community structure will be strongly influenced by global warming. This is particularly relevant in the tropics, where organisms are already living close to their upper temperature limits and hence are highly vulnerable to rising temperature. Here we present data on upper temperature limits of 34 tropical marine ectotherm species from seven phyla living in intertidal and subtidal habitats. Short term thermal tolerances and vertical distributions were correlated, i.e., upper shore animals have higher thermal tolerance than lower shore and subtidal animals; however, animals, despite their respective tidal height, were susceptible to the same temperature in the long term. When temperatures were raised by 1°C hour−1, the upper lethal temperature range of intertidal ectotherms was 41–52°C, but this range was narrower and reduced to 37–41°C in subtidal animals. The rate of temperature change, however, affected intertidal and subtidal animals differently. In chronic heating experiments when temperature was raised weekly or monthly instead of every hour, upper temperature limits of subtidal species decreased from 40°C to 35.4°C, while the decrease was more than 10°C in high shore organisms. Hence in the long term, activity and survival of tropical marine organisms could be compromised just 2–3°C above present seawater temperatures. Differences between animals from environments that experience different levels of temperature variability suggest that the physiological mechanisms underlying thermal sensitivity may vary at different rates of warming. PMID:22242115

  10. Learn locally, act globally: learning language from variation set cues.

    PubMed

    Onnis, Luca; Waterfall, Heidi R; Edelman, Shimon

    2008-12-01

    Variation set structure--partial overlap of successive utterances in child-directed speech--has been shown to correlate with progress in children's acquisition of syntax. We demonstrate the benefits of variation set structure directly: in miniature artificial languages, arranging a certain proportion of utterances in a training corpus in variation sets facilitated word and phrase constituent learning in adults. Our findings have implications for understanding the mechanisms of L1 acquisition by children, and for the development of more efficient algorithms for automatic language acquisition, as well as better methods for L2 instruction.

  11. Global surface temperature/heat transfer measurements using infrared imaging

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran

    1992-01-01

    A series of studies were conducted to evaluate the use of scanning radiometric infrared imaging systems for providing global surface temperature/heat transfer measurements in support of hypersonic wind tunnel testing. The in situ precision of the technique with narrow temperature span setting over the temperature range of 20 to 200 C was investigated. The precision of the technique over wider temperature span settings was also determined. The accuracy of technique for providing aerodynamic heating rates was investigated by performing measurements on a 10.2-centimeter hemisphere model in the Langley 31-inch Mach 10 tunnel, and comparing the results with theoretical predictions. Data from tests conducted on a generic orbiter model in this tunnel are also presented.

  12. Precise monitoring of global temperature trends from satellites

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1990-01-01

    Passive microwave radiometry from satellites provides more precise atmospheric temperature information than that obtained from the relatively sparse distribution of thermometers over the earth's surface. Accurate global atmospheric temperature estimates are needed for detection of possible greenhouse warming, evaluation of computer models of climate change, and for understanding important factors in the climate system. Analysis of the first 10 years (1979 to 1988) of satellite measurements of lower atmospheric temperature changes reveals a monthly precision of 0.01 C, large temperature variability on time scales from weeks to several years, but no obvious trend for the 10-year period. The warmest years, in descending order, were 1987, 1988, 1983, and 1980. The years 1984, 1985, and 1986 were the coolest.

  13. Precise monitoring of global temperature trends from satellites

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1990-01-01

    Passive microwave radiometry from satellites provides more precise atmospheric temperature information than that obtained from the relatively sparse distribution of thermometers over the earth's surface. Accurate global atmospheric temperature estimates are needed for detection of possible greenhouse warming, evaluation of computer models of climate change, and for understanding important factors in the climate system. Analysis of the first 10 years (1979 to 1988) of satellite measurements of lower atmospheric temperature changes reveals a monthly precision of 0.01 C, large temperature variability on time scales from weeks to several years, but no obvious trend for the 10-year period. The warmest years, in descending order, were 1987, 1988, 1983, and 1980. The years 1984, 1985, and 1986 were the coolest.

  14. Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

    PubMed

    Valle-Guadarrama, Salvador; Espinosa-Solares, Teodoro; López-Cruz, Irineo L; Domaschko, Max

    2011-05-01

    A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.

  15. Seasonal variations in the subauroral electron temperature enhancement

    SciTech Connect

    Fok, M.C.; Kozyra, J.U.; Warren, M.F. ); Brace, L.H. )

    1991-06-01

    The subauroral nightside electron temperature peak is one of the phenomena showing the response of the subauroral ionosphere to the influx of magnetic storm energy in the vicinity of the plasmapause. A statistical study of the seasonal variations of the subauroral electron temperature enhancement was undertaken using data from the Langmuir probe experiment on the DE 2 satellite throughout most of the mission (1981-1982). In the winter hemisphere the nighttime background electron temperature is the highest and the magnitude of the peak T{sub e} responds most weakly to the geomagnetic activity. This behavior can be explained by seasonal trends in the nighttime downward heat flux due to conjugate photoelectrons. Moreover, model results indicate that a factor of {approximately}3 increase in heat inflow during equinox relative to solstice is required to raise the electron temperature to a given level. This is a consequence of the higher electron densities at the T{sub e} peak near equinox. The T{sub e} peak occurs on field lines which thread the outer plasmasphere in the vicinity of the plasmapause and thus can be used as a tracer of the plasmapause position. Correlating the position of the T{sub e} peak with K{sub p} (the highest value of 3-hour K{sub p} in the preceding 12 hours) indicates a trend toward a more expanded quiet time plasmasphere and one which is more easily compressed by magnetic storms at equinox than during the solstice period.

  16. Seasonal variation in equatorial mesospheric temperatures observed by SME

    NASA Astrophysics Data System (ADS)

    Garcia, Rolando R.; Clancy, R. Todd

    1990-07-01

    Observations made by the Solar Mesosphere Explorer (SME) satellite from 1982 through 1986 are used to examine the seasonal variation of temperature in the equatorial mesosphere between 58.5 and 90 km. Near the equator, seasonal variability is dominated by a strong semiannual oscillation (SAO) whose amplitude increases from about 3 K in the lower mesosphere to 7.3 K near 80 km. Above 80 k, the SAO amplitude decreases to a minimum at 83 km, but increases again sharply above that level, reaching 16.6 K at 90 km. The structure of the temperature SAO is consistent with previous observations of the SAOs in temperature and zonal wind, although the very large amplitude at 90 km may be due in part to contamination by the diurnal tide. Just below 80 km, temperatures are warm (cold) near the solstices (equinoxes), implying westerly (easterly) accelerations above; the behavior at 58.5 km lags that at 80 km by about 2 months.

  17. Variations in atmospheric CO2 growth rates coupled with tropical temperature

    PubMed Central

    Wang, Weile; Ciais, Philippe; Nemani, Ramakrishna R.; Canadell, Josep G.; Piao, Shilong; Sitch, Stephen; White, Michael A.; Hashimoto, Hirofumi; Milesi, Cristina; Myneni, Ranga B.

    2013-01-01

    Previous studies have highlighted the occurrence and intensity of El Niño–Southern Oscillation as important drivers of the interannual variability of the atmospheric CO2 growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r2 ≈ 0.50) between interannual variations of the CO2 growth rate and tropical land–surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to a 3.5 ± 0.6 Petagrams of carbon per year (PgC/y) CO2 growth-rate anomaly on average. Analysis of simulation results from Dynamic Global Vegetation Models suggests that this temperature–CO2 coupling is contributed mainly by the additive responses of heterotrophic respiration (Rh) and net primary production (NPP) to temperature variations in tropical ecosystems. However, we find a weaker and less consistent (r2 ≈ 0.25) interannual coupling between CO2 growth rate and tropical land precipitation than diagnosed from the Dynamic Global Vegetation Models, likely resulting from the subtractive responses of tropical Rh and NPP to precipitation anomalies that partly offset each other in the net ecosystem exchange (i.e., net ecosystem exchange ≈ Rh − NPP). Variations in other climate variables (e.g., large-scale cloudiness) and natural disturbances (e.g., volcanic eruptions) may induce transient reductions in the temperature–CO2 coupling, but the relationship is robust during the past 50 y and shows full recovery within a few years after any such major variability event. Therefore, it provides an important diagnostic tool for improved understanding of the contemporary and future global carbon cycle. PMID:23884654

  18. On the causal structure between CO2 and global temperature

    PubMed Central

    Stips, Adolf; Macias, Diego; Coughlan, Clare; Garcia-Gorriz, Elisa; Liang, X. San

    2016-01-01

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing, and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes. PMID:26900086

  19. On the causal structure between CO2 and global temperature

    NASA Astrophysics Data System (ADS)

    Stips, Adolf; Macias, Diego; Coughlan, Clare; Garcia-Gorriz, Elisa; Liang, X. San

    2016-02-01

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing, and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes.

  20. On the causal structure between CO2 and global temperature.

    PubMed

    Stips, Adolf; Macias, Diego; Coughlan, Clare; Garcia-Gorriz, Elisa; Liang, X San

    2016-02-22

    We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing, and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes.

  1. Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?

    USGS Publications Warehouse

    Love, J.J.; Mursula, K.; Tsai, V.C.; Perkins, D.M.

    2011-01-01

    Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868-2008, solar cycles 11-23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically- significant correlation between sunspot number and geomagnetic activity, Pearson p < 10-4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction. ?? 2011 by the American Geophysical Union.

  2. Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease.

    PubMed

    Rohr, Jason R; Raffel, Thomas R

    2010-05-04

    The role of global climate change in the decline of biodiversity and the emergence of infectious diseases remains controversial, and the effect of climatic variability, in particular, has largely been ignored. For instance, it was recently revealed that the proposed link between climate change and widespread amphibian declines, putatively caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), was tenuous because it was based on a temporally confounded correlation. Here we provide temporally unconfounded evidence that global El Niño climatic events drive widespread amphibian losses in genus Atelopus via increased regional temperature variability, which can reduce amphibian defenses against pathogens. Of 26 climate variables tested, only factors associated with temperature variability could account for the spatiotemporal patterns of declines thought to be associated with Bd. Climatic predictors of declines became significant only after controlling for a pattern consistent with epidemic spread (by temporally detrending the data). This presumed spread accounted for 59% of the temporal variation in amphibian losses, whereas El Niño accounted for 59% of the remaining variation. Hence, we could account for 83% of the variation in declines with these two variables alone. Given that global climate change seems to increase temperature variability, extreme climatic events, and the strength of Central Pacific El Niño episodes, climate change might exacerbate worldwide enigmatic declines of amphibians, presumably by increasing susceptibility to disease. These results suggest that changes to temperature variability associated with climate change might be as significant to biodiversity losses and disease emergence as changes to mean temperature.

  3. Linking global climate and temperature variability to widespread amphibian declines putatively caused by disease

    PubMed Central

    Rohr, Jason R.; Raffel, Thomas R.

    2010-01-01

    The role of global climate change in the decline of biodiversity and the emergence of infectious diseases remains controversial, and the effect of climatic variability, in particular, has largely been ignored. For instance, it was recently revealed that the proposed link between climate change and widespread amphibian declines, putatively caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), was tenuous because it was based on a temporally confounded correlation. Here we provide temporally unconfounded evidence that global El Niño climatic events drive widespread amphibian losses in genus Atelopus via increased regional temperature variability, which can reduce amphibian defenses against pathogens. Of 26 climate variables tested, only factors associated with temperature variability could account for the spatiotemporal patterns of declines thought to be associated with Bd. Climatic predictors of declines became significant only after controlling for a pattern consistent with epidemic spread (by temporally detrending the data). This presumed spread accounted for 59% of the temporal variation in amphibian losses, whereas El Niño accounted for 59% of the remaining variation. Hence, we could account for 83% of the variation in declines with these two variables alone. Given that global climate change seems to increase temperature variability, extreme climatic events, and the strength of Central Pacific El Niño episodes, climate change might exacerbate worldwide enigmatic declines of amphibians, presumably by increasing susceptibility to disease. These results suggest that changes to temperature variability associated with climate change might be as significant to biodiversity losses and disease emergence as changes to mean temperature. PMID:20404180

  4. Inland Water Temperature and the recent Global Warming Hiatus

    NASA Astrophysics Data System (ADS)

    Hook, S. J.; Healey, N.; Lenters, J. D.; O'Reilly, C.

    2015-12-01

    We are using thermal infrared satellite data in conjunction with in situ measurements to produce water temperatures for all the large inland water bodies in North America and the rest of the world for potential use as climate indicator. Recent studies have revealed significant warming of inland waters throughout the world. The observed rate of warming is - in many cases - greater than that of the ambient air temperature. These rapid, unprecedented changes in inland water temperatures have profound implications for lake hydrodynamics, productivity, and biotic communities. Scientists are just beginning to understand the global extent, regional patterns, physical mechanisms, and ecological consequences of lake warming. As part of our earlier studies we have collected thermal infrared satellite data from those satellite sensors that provide long-term and frequent spaceborne thermal infrared measurements of inland waters including ATSR, AVHRR, and MODIS and used these to examine trends in water surface temperature for approximately 169 of the largest inland water bodies in the world. We are now extending this work to generate temperature time-series of all North American inland water bodies that are sufficiently large to be studied using 1km resolution satellite data for the last 3 decades, approximately 268 lakes. These data are then being related to changes in the surface air temperature and compared with regional trends in water surface temperature derived from CMIP5/IPCC model simulations/projections to better predict future temperature changes. We will discuss the available datasets and processing methodologies together with the patterns they reveal based on recent changes in the global warming, with a particular focus on the inland waters of the southwestern USA.

  5. Control Performance of ER Engine Mount Subjected to Temperature Variations

    NASA Astrophysics Data System (ADS)

    Song, H. J.; Choi, S. B.; Kim, K. S.

    A key function of engine mount of vehicle systems is to support engine mass and isolate noise and vibration from engine disturbance forces. One of attractive candidates to achieve this goal is to utilize a semi-active ER engine mount. By applying this, we can effectively control damping force and hence the noise and vibration by just controlling the intensity of electric field. However, control performance of the engine mount may be very sensitive to temperature variation during engine operation. In this work, we investigate dynamic and control performances of ER engine mount with respect to the temperature variation. In order to undertake this, a flow-mode type of ER engine mount is designed and manufactured. Displacement transmissibility is experimentally evaluated for 1 degree of freedom. The ER engine mount is then incorporated with full-vehicle model in order to investigate vibration control performance. After formulating the governing equation of motion, a semi-active controller is designed. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at various engine speeds are evaluated in the frequency and time domains.

  6. Precipitation, temperature, and moisture transport variations associated with two distinct ENSO flavors during 1979-2014

    NASA Astrophysics Data System (ADS)

    Gu, Guojun; Adler, Robert F.

    2016-11-01

    Interannual precipitation and temperature variations during 1979-2014 are investigated by examining the effects of two distinct flavors of the El Niño-Southern Oscillation (ENSO), i.e., the tropical eastern Pacific (EP) and central Pacific (CP) ENSO events. Satellite- and ground-based observations with global coverage are applied including the monthly precipitation data from the Global Precipitation Climatology Project (GPCP) and surface temperature anomalies from the NASA-GISS surface temperature anomaly analysis. Related variations in other water-cycle components including atmospheric moisture transport are also examined by using the outputs from the NASA-Modern Era Retrospective-analysis for Research and Applications (MERRA). While the second leading mode from an EOF analysis of sea surface temperature (SST) anomalies between 30°N and 30°S is dominated by interdecadal-scale variability that is not a focus of this study, the first and third leading modes represent well the EP and CP events, respectively. The corresponding principal components (PC1 and PC3) are then applied as indices to estimate the influences of the two ENSO flavors on various physical components through linear regression. Because of their distinct SST configurations in the tropical Pacific, the two ENSO flavors manifest different spatial features of precipitation anomalies as shown in past studies. Differences can also be readily seen in satellite-retrieved tropospheric layered temperatures and oceanic columnar water vapor content. General agreements between observations and MERRA outputs can be obtained as judged by consistent respective anomalies corresponding to the two ENSO flavors, suggesting that MERRA could provide an accurate account of variations on the interannual time scale. Interannual variations in MERRA vertically integrated moisture transport (VIMT) are further examined to explore possible relations between precipitation and tropospheric moisture transport corresponding to the

  7. Temperature-associated increases in the global soil respiration record.

    PubMed

    Bond-Lamberty, Ben; Thomson, Allison

    2010-03-25

    Soil respiration, R(S), the flux of microbially and plant-respired carbon dioxide (CO(2)) from the soil surface to the atmosphere, is the second-largest terrestrial carbon flux. However, the dynamics of R(S) are not well understood and the global flux remains poorly constrained. Ecosystem warming experiments, modelling analyses and fundamental biokinetics all suggest that R(S) should change with climate. This has been difficult to confirm observationally because of the high spatial variability of R(S), inaccessibility of the soil medium and the inability of remote-sensing instruments to measure R(S) on large scales. Despite these constraints, it may be possible to discern climate-driven changes in regional or global R(S) values in the extant four-decade record of R(S) chamber measurements. Here we construct a database of worldwide R(S) observations matched with high-resolution historical climate data and find a previously unknown temporal trend in the R(S) record after accounting for mean annual climate, leaf area, nitrogen deposition and changes in CO(2) measurement technique. We find that the air temperature anomaly (the deviation from the 1961-1990 mean) is significantly and positively correlated with changes in R(S). We estimate that the global R(S) in 2008 (that is, the flux integrated over the Earth's land surface over 2008) was 98 +/- 12 Pg C and that it increased by 0.1 Pg C yr(-1) between 1989 and 2008, implying a global R(S) response to air temperature (Q(10)) of 1.5. An increasing global R(S) value does not necessarily constitute a positive feedback to the atmosphere, as it could be driven by higher carbon inputs to soil rather than by mobilization of stored older carbon. The available data are, however, consistent with an acceleration of the terrestrial carbon cycle in response to global climate change.

  8. A computer model of global thermospheric winds and temperatures

    NASA Technical Reports Server (NTRS)

    Killeen, T. L.; Roble, R. G.; Spencer, N. W.

    1987-01-01

    Output data from the NCAR Thermospheric GCM and a vector-spherical-harmonic (VSH) representation of the wind field are used in constructing a computer model of time-dependent global horizontal vector neutral wind and temperature fields at altitude 130-300 km. The formulation of the VSH model is explained in detail, and some typical results obtained with a preliminary version (applicable to December solstice at solar maximum) are presented graphically. Good agreement with DE-2 satellite measurements is demonstrated.

  9. Diurnal Variations of Titan's Surface Temperatures From Cassini -CIRS Observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, Conor; Jennings, Don; Anderson, Carrie; Samuelson, Robert; Irwin, Patrick; Flasar, F. Michael

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 m (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the in-strument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature pro-file by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp

  10. General atmospheric circulation driven by polar and diurnal surface temperature variations.

    NASA Technical Reports Server (NTRS)

    Bohachevsky, I. O.

    1973-01-01

    Described is a global circulation model for the Venus atmosphere that includes the effects of both polar cooling and diurnal temperature variation. It is based on a linearized Boussinesq approximation and boundary conditions derived from theoretical and empirical considerations. The time-dependent, three-dimensional flow field is deduced without any a priori assumptions about its configuration. Results show that the mean atmospheric motions are essentially zonal in a narrow belt near the equator and change to become meridional over most of the globe. The circulation pattern is not symmetrical and rotates about the polar axis of the planet with the period of the solar day.

  11. Regions of significant influence on unforced global mean surface air temperature variability in climate models

    NASA Astrophysics Data System (ADS)

    Brown, Patrick T.; Li, Wenhong; Xie, Shang-Ping

    2015-01-01

    We document the geographic regions where local variability is most associated with unforced global mean surface air temperature (GMT) variability in Coupled Model Intercomparison Project Phase 5 coupled global climate models (GCMs) at both the subdecadal and interdecadal timescales. For this purpose, Regions of Significant Influence on GMT are defined as locations that have a statistically significant correlation between local surface air temperature (SAT) and GMT (with a regression slope greater than 1), and where local SAT variation leads GMT variation in time. In both GCMs and observations, subdecadal timescale GMT variability is most associated with SAT variation over the eastern equatorial Pacific. At the interdecadal timescale, GMT variability is also linked with SAT variation over the Pacific in many GCMs, but the particular spatial patterns are GCM dependent, and several GCMs indicate a primary association between GMT and SAT over the Southern Ocean. We find that it is difficult to validate GCM behavior at the interdecadal timescale because the pattern derived from observations is highly depended on the method used to remove the forced variability from the record. The magnitude of observed GMT variability is near the ensemble median at the subdecadal timescale but well above the median at the interdecadal timescale. GCMs with a stronger subdecadal relationship between GMT and SAT over the Pacific tend to have more variable subdecadal GMT while GCMs with a stronger interdecadal relationship between GMT and SAT over parts of the Southern Ocean tend to have more variable GMT.

  12. Simultaneous stabilization of global temperature and precipitation through cocktail geoengineering

    NASA Astrophysics Data System (ADS)

    Cao, Long; Duan, Lei; Bala, Govindasamy; Caldeira, Ken

    2017-07-01

    Solar geoengineering has been proposed as a backup plan to offset some aspects of anthropogenic climate change if timely CO2 emission reductions fail to materialize. Modeling studies have shown that there are trade-offs between changes in temperature and hydrological cycle in response to solar geoengineering. Here we investigate the possibility of stabilizing both global mean temperature and precipitation simultaneously by combining two geoengineering approaches: stratospheric sulfate aerosol increase (SAI) that deflects sunlight to space and cirrus cloud thinning (CCT) that enables more longwave radiation to escape to space. Using the slab ocean configuration of National Center for Atmospheric Research Community Earth System Model, we simulate SAI by uniformly adding sulfate aerosol in the upper stratosphere and CCT by uniformly increasing cirrus cloud ice particle falling speed. Under an idealized warming scenario of abrupt quadrupling of atmospheric CO2, we show that by combining appropriate amounts of SAI and CCT geoengineering, global mean (or land mean) temperature and precipitation can be restored simultaneously to preindustrial levels. However, compared to SAI, cocktail geoengineering by mixing SAI and CCT does not markedly improve the overall similarity between geoengineered climate and preindustrial climate on regional scales. Some optimal spatially nonuniform mixture of SAI with CCT might have the potential to better mitigate climate change at both the global and regional scales.

  13. Response of tropical clouds to the interannual variation of sea surface temperature

    SciTech Connect

    Fu, Rong; Liu, W.T.

    1996-03-01

    Connections between large-scale interannual variations of clouds, deep convection, atmospheric winds, vertical thermodynamic structure, and sea surface temperatures (SST) over global tropical oceans are examined. SST warming associated with El Nino significantly impacted the global tropical cloud field. Extensive variations of the total cloud field, dominated by changes of high and middle clouds, occurred in the northeastern Indian, western and central Pacific, and western Atlantic Oceans. Total cloud variation, dominated by low cloud variation, was relatively weak in the eastern Pacific and the Atlantic due to cancellation between high and low cloud changes. Destabilization of the lapse rate between 900 and 750 mb was more important in enhancing convective instability than was the change of local SST in the equatorial central Pacific during the 1987 El Nino. In the subtropical Pacific, the change of lapse rate between 900 and 750 mb associated with anomalous subsidence and the decrease of boundary-layer buoyancy due to a decrease of temperature and moisture were important in enhancing convective stability. Consequently, convection and high and middle clouds decreased in these areas. The change of low clouds in the equatoral and southeastern Atlantic correlated to local SST and SST changes in the equatorial eastern Pacific, and the increase of low clouds was consistent with the sharper inversion during the 1987 El Nino. The coherence between clouds and SST tendency shows that SST tendency leads cloud variation in the equatorial Pacific. Thus, the change of clouds does not dominate the sign of SST tendency even though the cloud change was maximum during the 1987 El Nino. In some areas of the Indian, subtropical Pacific, and North Atlantic Oceans, cloud change leads SST tendency. Cloud change might affect SST tendency in these regions. 60 refs., 12 figs., 1 tab.

  14. Is the global mean temperature trend too low?

    NASA Astrophysics Data System (ADS)

    Venema, Victor; Lindau, Ralf

    2015-04-01

    The global mean temperature trend may be biased due to similar technological and economic developments worldwide. In this study we want to present a number of recent results that suggest that the global mean temperature trend might be steeper as generally thought. In the Global Historical Climate Network version 3 (GHCNv3) the global land surface temperature is estimated to have increased by about 0.8°C between 1880 and 2012. In the raw temperature record, the increase is 0.6°C; the 0.2°C difference is due to homogenization adjustments. Given that homogenization can only reduce biases, this 0.2°C stems from a partial correction of bias errors and it seems likely that the real non-climatic trend bias will be larger. Especially in regions with sparser networks, homogenization will not be able to improve the trend much. Thus if the trend bias in these regions is similar to the bias for more dense networks (industrialized countries), one would expect the real bias to be larger. Stations in sparse networks are representative for a larger region and are given more weight in the computation of the global mean temperature. If all stations are given equal weight, the homogenization adjustments of the GHCNv3 dataset are about 0.4°C per century. In the subdaily HadISH dataset one break with mean size 0.12°C is found every 15 years for the period 1973-2013. That would be a trend bias of 0.78°C per century on a station by station basis. Unfortunately, these estimates strongly focus on Western countries having more stations. It is known from the literature that rich countries have a (statistically insignificant) stronger trend in the global datasets. Regional datasets can be better homogenized than global ones, the main reason being that global datasets do not contain all stations known to the weather services. Furthermore, global datasets use automatic homogenization methods and have less or no metadata. Thus while regional data can be biased themselves, comparing them

  15. Impacts of climatic variation on trout: A global synthesis and path forward

    USGS Publications Warehouse

    Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Dunham, Jason; Letcher, Benjamin; Kershner, Jeffrey L.

    2016-01-01

    Despite increasing concern that climate change may negatively impact trout—a globally distributed group of fish with major economic, ecological, and cultural value—a synthetic assessment of empirical data quantifying relationships between climatic variation and trout ecology does not exist. We conducted a systematic review to describe how temporal variation in temperature and streamflow influences trout ecology in freshwater ecosystems. Few studies (n = 42) have quantified relationships between temperature or streamflow and trout demography, growth, or phenology, and nearly all estimates (96 %) were for Salvelinus fontinalis and Salmo trutta. Only seven studies used temporal data to quantify climate-driven changes in trout ecology. Results from these studies were beset with limitations that prohibited quantitatively rigorous meta-analysis, a concerning inadequacy given major investment in trout conservation and management worldwide. Nevertheless, consistent patterns emerged from our synthesis, particularly a positive effect of summer streamflow on trout demography and growth; 64 % of estimates were positive and significant across studies, age classes, species, and locations, highlighting that climate-induced changes in hydrology may have numerous consequences for trout. To a lesser degree, summer and fall temperatures were negatively related to population demography (51 and 53 % of estimates, respectively), but temperature was rarely related to growth. To address limitations and uncertainties, we recommend: (1) systematically improving data collection, description, and sharing; (2) appropriately integrating climate impacts with other intrinsic and extrinsic drivers over the entire lifecycle; (3) describing indirect consequences of climate change; and (4) acknowledging and describing intrinsic resiliency.

  16. Cosmic ray intensity variations in connection with the level of precipitation and ground temperature variations

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.; Pustil'Nik, L. A.

    If cosmic ray ionization of lower atmosphere influenced on cloudiness covering, we will expect also some correllation of cosmic ray intensity with the level of precipitation and ground temperature variations: with increasing of cosmic ray intensity will be increase cloudiness covering, so we will expect increasing of the level of precipitation and decreasing of the ground temperature. We compare observed during many years on many meteorological stations in former USSR and later in Russia, as well as in Israel and other countries available data on time variations of the level of precipitation and ground temperature variations with cosmic ray data on cosmic ray variations from many stations of worldwide network and determined the regression and correlation coefficients. We discuss the obtained results in the frame of the problem of possible cosmic ray influence on processes in the atmosphere, on weather and climate change experiments effects of atmospheric electric field in cosmic rays. On the basis of cosmic ray and atmospheric electric field one minute data obtained by NM and EFS of Emilio Segre' Observatory (hight 2025 m above s.l., cosmic ray cut-off rigidity for vertical direction 10.8 GV) we determine the atmospheric electric field effect in CR for total neutron intensity and for multiplicities m ≥ 1, m ≥ 2, m ≥ 3, m ≥ 4, m ≥ 5, m ≥ 6, m ≥ 7, and m ≥ 8, as well as for m = 1, m = 2, m = 3, m = 4, m = 5, m = 6, and m = 7. For comparison and excluding primary CR variations we use also one minute data on neutron multiplicities obtained by NM in Rome and other cosmic ray stations. According to the theoretical calculations of Dorman and Dorman (2004) the electric field effect in the NM counting rate must be caused mainly by captchuring of slow negative muons by lead nucleus with escaping few neutrons. As it was shown in Dorman and Dorman (2004), the biggest electric field effect is expected in the multiplicity m = 1, much smaller in m = 2 and

  17. Multicomponent, multiphase flow in porous media with temperature variation

    SciTech Connect

    Wingard, J.S.; Orr, F.M. Jr.

    1990-10-01

    Recovery of hydrocarbons from porous media is an ongoing concern. Advanced techniques augment conventional recovery methods by injecting fluids that favorably interact with the oil. These fluids interact with the oil by energy transfer, in the case of steam injection, or by mass transfer, as in a miscible gas flood. Often both thermal and compositional considerations are important. An understanding of these injection methods requires knowledge of how temperature variations, phase equilibrium and multiphase flow in porous media interact. The material balance for each component and energy balance are cast as a system of non-strictly hyperbolic partial differential equations. This system of equations is solved using the method of characteristics. The model takes into account the phase behavior by using the Peng-Robinson equation of state to partition the individual components into different phases. Temperature effects are accounted for by the energy balance. Flow effects are modelled by using fractional flow curves and a Stone's three phase relative permeability model. Three problems are discussed. The first problem eliminates the phase behavior aspect of the problem by studying the flow of a single component as it undergoes an isothermal phase change. The second couples the effects of temperature and flow behavior by including a second component that is immiscible with the original component. Phase behavior is added by using a set of three partially miscible components that partition into two or three separate phases. 66 refs., 54 figs., 14 tabs.

  18. Rapid variations in deep ocean temperature detected in the Holocene

    NASA Astrophysics Data System (ADS)

    Bova, Samantha C.; Herbert, Timothy D.; Fox-Kemper, Baylor

    2016-12-01

    The observational record of deep ocean variability is short, which makes it difficult to attribute the recent rise in deep ocean temperatures to anthropogenic forcing. Here we test a new proxy—the oxygen isotopic signature of individual benthic foraminifera—to detect rapid (i.e., monthly to decadal) variations in deep ocean temperature and salinity in the sedimentary record. We apply this technique at 1000 m water depth in the Eastern Equatorial Pacific during seven 200 year Holocene intervals. Variability in foraminifer δ18O over the past 200 years is below the detection limit, but δ18O signatures from two mid-Holocene intervals indicate temperature swings >2°C within 200 years. More vigorous transport between the surface and deep ocean or stronger eddy variability than that observed in the historical record are potential explanations. Distinguishing externally forced climate trends in deep ocean properties from unforced variability should be possible with systematic analysis of suitable deep sea cores.

  19. Global temperature responses to current emissions from the transport sectors

    PubMed Central

    Berntsen, Terje; Fuglestvedt, Jan

    2008-01-01

    Transport affects climate directly and indirectly through mechanisms that cause both warming and cooling of climate, and the effects operate on very different timescales. We calculate climate responses in terms of global mean temperature and find large differences between the transport sectors with respect to the size and mix of short- and long-lived effects, and even the sign of the temperature response. For year 2000 emissions, road transport has the largest effect on global mean temperature. After 20 and 100 years the response in net temperature is 7 and 6 times higher, respectively, than for aviation. Aviation and shipping have strong but quite uncertain short-lived warming and cooling effects, respectively, that dominate during the first decades after the emissions. For shipping the net cooling during the first 4 decades is due to emissions of SO2 and NOx. On a longer timescale, the current emissions from shipping cause net warming due to the persistence of the CO2 perturbation. If emissions stay constant at 2000 levels, the warming effect from road transport will continue to increase and will be almost 4 times larger than that of aviation by the end of the century. PMID:19047640

  20. Global temperature responses to current emissions from the transport sectors.

    PubMed

    Berntsen, Terje; Fuglestvedt, Jan

    2008-12-09

    Transport affects climate directly and indirectly through mechanisms that cause both warming and cooling of climate, and the effects operate on very different timescales. We calculate climate responses in terms of global mean temperature and find large differences between the transport sectors with respect to the size and mix of short- and long-lived effects, and even the sign of the temperature response. For year 2000 emissions, road transport has the largest effect on global mean temperature. After 20 and 100 years the response in net temperature is 7 and 6 times higher, respectively, than for aviation. Aviation and shipping have strong but quite uncertain short-lived warming and cooling effects, respectively, that dominate during the first decades after the emissions. For shipping the net cooling during the first 4 decades is due to emissions of SO(2) and NOx. On a longer timescale, the current emissions from shipping cause net warming due to the persistence of the CO(2) perturbation. If emissions stay constant at 2000 levels, the warming effect from road transport will continue to increase and will be almost 4 times larger than that of aviation by the end of the century.

  1. Global Surface Temperature Response Explained by Multibox Energy Balance Models

    NASA Astrophysics Data System (ADS)

    Fredriksen, H. B.; Rypdal, M.

    2016-12-01

    We formulate a multibox energy balance model, from which global temperature evolution can be described by convolving a linear response function and a forcing record. We estimate parameters in the response function from instrumental data and historic forcing, such that our model can produce a response to both deterministic forcing and stochastic weather forcing consistent with observations. Furthermore, if we make separate boxes for upper ocean layer and atmosphere over land, we can also make separate response functions for global land and sea surface temperature. By describing internal variability as a linear response to white noise, we demonstrate that the power-law form of the observed temperature spectra can be described by linear dynamics, contrary to a common belief that these power-law spectra must arise from nonlinear processes. In our multibox model, the power-law form can arise due to the multiple response times. While one of our main points is that the climate system responds over a wide range of time scales, we cannot find one set of time scales that can be preferred compared to other choices. Hence we think the temperature response can best be characterized as something that is scale-free, but still possible to approximate by a set of well separated time scales.

  2. Interactions between temperature and drought in global and regional crop yield variability during 1961-2014

    PubMed Central

    Matiu, Michael; Ankerst, Donna P.; Menzel, Annette

    2017-01-01

    Inter-annual crop yield variation is driven in large parts by climate variability, wherein the climate components of temperature and precipitation often play the biggest role. Nonlinear effects of temperature on yield as well as interactions among the climate variables have to be considered. Links between climate and crop yield variability have been previously studied, both globally and at regional scales, but typically with additive models with no interactions, or when interactions were included, with implications not fully explained. In this study yearly country level yields of maize, rice, soybeans, and wheat of the top producing countries were combined with growing season temperature and SPEI (standardized precipitation evapotranspiration index) to determine interaction and intensification effects of climate variability on crop yield variability during 1961–2014. For maize, soybeans, and wheat, heat and dryness significantly reduced yields globally, while global effects for rice were not significant. But because of interactions, heat was more damaging in dry than in normal conditions for maize and wheat, and temperature effects were not significant in wet conditions for maize, soybeans, and wheat. Country yield responses to climate variability naturally differed between the top producing countries, but an accurate description of interaction effects at the country scale required sub-national data (shown only for the USA). Climate intensification, that is consecutive dry or warm years, reduced yields additionally in some cases, however, this might be linked to spillover effects of multiple growing seasons. Consequently, the effect of temperature on yields might be underestimated in dry conditions: While there were no significant global effects of temperature for maize and soybeans yields for average SPEI, the combined effects of high temperatures and drought significantly decreased yields of maize, soybeans, and wheat by 11.6, 12.4, and 9.2%, respectively. PMID

  3. Interactions between temperature and drought in global and regional crop yield variability during 1961-2014.

    PubMed

    Matiu, Michael; Ankerst, Donna P; Menzel, Annette

    2017-01-01

    Inter-annual crop yield variation is driven in large parts by climate variability, wherein the climate components of temperature and precipitation often play the biggest role. Nonlinear effects of temperature on yield as well as interactions among the climate variables have to be considered. Links between climate and crop yield variability have been previously studied, both globally and at regional scales, but typically with additive models with no interactions, or when interactions were included, with implications not fully explained. In this study yearly country level yields of maize, rice, soybeans, and wheat of the top producing countries were combined with growing season temperature and SPEI (standardized precipitation evapotranspiration index) to determine interaction and intensification effects of climate variability on crop yield variability during 1961-2014. For maize, soybeans, and wheat, heat and dryness significantly reduced yields globally, while global effects for rice were not significant. But because of interactions, heat was more damaging in dry than in normal conditions for maize and wheat, and temperature effects were not significant in wet conditions for maize, soybeans, and wheat. Country yield responses to climate variability naturally differed between the top producing countries, but an accurate description of interaction effects at the country scale required sub-national data (shown only for the USA). Climate intensification, that is consecutive dry or warm years, reduced yields additionally in some cases, however, this might be linked to spillover effects of multiple growing seasons. Consequently, the effect of temperature on yields might be underestimated in dry conditions: While there were no significant global effects of temperature for maize and soybeans yields for average SPEI, the combined effects of high temperatures and drought significantly decreased yields of maize, soybeans, and wheat by 11.6, 12.4, and 9.2%, respectively.

  4. Climate, soil and plant functional types as drivers of global fine-root trait variation

    DOE PAGES

    Freschet, Grégoire T.; Valverde-Barrantes, Oscar J.; Tucker, Caroline M.; ...

    2017-03-08

    Ecosystem functioning relies heavily on below-ground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and environmental variation. We compiled a world-wide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypothesesmore » that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness. We demonstrate that: (i) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (ii) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (iii) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N2-fixing capacity positively relates to root nitrogen; and (iv) Plants growing in pots have higher SRL than those grown in the field. Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two

  5. Interannual Variations in Simulated and Observed MSU-2 Temperatures

    SciTech Connect

    Boyle, J.

    2000-08-16

    Microwave Sounding Unit (MSU) channel 2 temperatures are computed for three sets of model experiments and their interannual variation is compared to that of the observed. The models used are: (1) an ensemble of ten integrations of the NCAR CCM3 using prescribed SSTs for 1979 t o 1995, (2) A 300 year integration of the NCAR/DOE Parallel Climate Model (which has the CCM3 as the atmospheric model) and (3) a 300 year integration of the ECHAM4/OPYC coupled model at the Max Planck Institute for Meteorology. In addition Nino34 and AO indices were computed from SST and MSLP of each data set. The observed data spanned the period of 1979 to 1998. The CCM3 integrations used the observed SSTs from 1979 to 1995. The 300 year coupled runs were divided into non-overlapping 20 year segments and each segment was processed independently. The EOFs of the zonally averaged, monthly mean MSU-2 anomalies were computed. An SVD analysis of the covariance of the tropical (30S-30N) precipitation and MSU-2 was carried out. The first and second mode of the observations are related to the ENSO variations and the Arctic Oscillation, respectively. The Nino34 index leads the ENSO mode by 5 months in the observations. For the nine realizations of the CCM3, all have the ENSO as the leading mode but one does not have the AO as the second. The lag between the Nino34 and leading EOF decreases to about 3 months.The fourteen PCM 20 year segments show a similar variation to the CCM3, but the lag is decreased to 2 months. All fourteen of the ECHAM segments have the ENSO and AO as the leading and second modes. The fourteen ECHAM data sets evince smaller variations between segments than the PCM and even the CCM3 realizations. The lag between the ECHAM Nino34 and the leading EOF is about 3 months.Thus, both coupled models have a substantially faster response to variations in tropical SSTs. This can affect the way that these models simulate the relation between the seasonal cycle and ENSO.

  6. Possible forcing of global temperature by the oceanic tides

    PubMed Central

    Keeling, Charles D.; Whorf, Timothy P.

    1997-01-01

    An approximately decadal periodicity in surface air temperature is discernable in global observations from A.D. 1855 to 1900 and since A.D. 1945, but with a periodicity of only about 6 years during the intervening period. Changes in solar irradiance related to the sunspot cycle have been proposed to account for the former, but cannot account for the latter. To explain both by a single mechanism, we propose that extreme oceanic tides may produce changes in sea surface temperature at repeat periods, which alternate between approximately one-third and one-half of the lunar nodal cycle of 18.6 years. These alternations, recurring at nearly 90-year intervals, reflect varying slight degrees of misalignment and departures from the closest approach of the Earth with the Moon and Sun at times of extreme tide raising forces. Strong forcing, consistent with observed temperature periodicities, occurred at 9-year intervals close to perihelion (solar perigee) for several decades centered on A.D. 1881 and 1974, but at 6-year intervals for several decades centered on A.D. 1923. As a physical explanation for tidal forcing of temperature we propose that the dissipation of extreme tides increases vertical mixing of sea water, thereby causing episodic cooling near the sea surface. If this mechanism correctly explains near-decadal temperature periodicities, it may also apply to variability in temperature and climate on other times-scales, even millennial and longer. PMID:11607740

  7. Global warming and urbanization affect springwater temperatures in Tokyo, Japan

    NASA Astrophysics Data System (ADS)

    Matsuyama, H.

    2014-02-01

    Due to global warming and urbanization, air temperature in Tokyo has risen 1.6 degrees in the past 30-40 years which has also affected springwater temperatures. From 2005, we have proceeded with the observations of springs in Tokyo metropolis, Japan which had been conducted by Environment of Tokyo from the end of the 1980s to 2001. In the rainy season (October) and dry season (February), we have observed springwater temperatures in 25 springs. The field surveys have revealed that most springwater temperatures has steadly risen in the past 30 years. As of February 2013, water temperatures of 19/11 springs have risen with 5% level in the rainy/dry season. As of February 2006, water temperatures of 10/13 springs have risen with 5% level in the rainy/dry season, i.e., 9/2 springs have acquired/lost the significance as of February 2013. One possible reason is the recent hot summer/cold winter in Tokyo.

  8. UAH Version 6 global satellite temperature products: Methodology and results

    NASA Astrophysics Data System (ADS)

    Spencer, Roy W.; Christy, John R.; Braswell, William D.

    2017-02-01

    Version 6 of the UAH MSU/AMSU global satellite temperature dataset represents an extensive revision of the procedures employed in previous versions of the UAH datasets. The two most significant results from an end-user perspective are (1) a decrease in the global-average lower tropospheric temperature (LT) trend from +0.14°C decade-1 to +0.11°C decade-1 (Jan. 1979 through Dec. 2015); and (2) the geographic distribution of the LT trends, including higher spatial resolution, owing to a new method for computing LT. We describe the major changes in processing strategy, including a new method for monthly gridpoint averaging which uses all of the footprint data yet eliminates the need for limb correction; a new multi-channel (rather than multi-angle) method for computing the lower tropospheric (LT) temperature product which requires an additional tropopause (TP) channel to be used; and a new empirical method for diurnal drift correction. We show results for LT, the midtroposphere (MT, from MSU2/AMSU5), and lower stratosphere (LS, from MSU4/AMSU9). A 0.03°C decade-1 reduction in the global LT trend from the Version 5.6 product is partly due to lesser sensitivity of the new LT to land surface skin temperature (est. 0.01°C decade-1), with the remainder of the reduction (0.02°C decade-1) due to the new diurnal drift adjustment, the more robust method of LT calculation, and other changes in processing procedures.

  9. Calling behaviour under climate change: geographical and seasonal variation of calling temperatures in ectotherms.

    PubMed

    Llusia, Diego; Márquez, Rafael; Beltrán, Juan F; Benítez, Maribel; do Amaral, José P

    2013-09-01

    Calling behaviour is strongly temperature-dependent and critical for sexual selection and reproduction in a variety of ectothermic taxa, including anuran amphibians, which are the most globally threatened vertebrates. However, few studies have explored how species respond to distinct thermal environments at time of displaying calling behaviour, and thus it is still unknown whether ongoing climate change might compromise the performance of calling activity in ectotherms. Here, we used new audio-trapping techniques (automated sound recording and detection systems) between 2006 and 2009 to examine annual calling temperatures of five temperate anurans and their patterns of geographical and seasonal variation at the thermal extremes of species ranges, providing insights into the thermal breadths of calling activity of species, and the mechanisms that enable ectotherms to adjust to changing thermal environments. All species showed wide thermal breadths during calling behaviour (above 15 °C) and increases in calling temperatures in extremely warm populations and seasons. Thereby, calling temperatures differed both geographically and seasonally, both in terrestrial and aquatic species, and were 8-22 °C below the specific upper critical thermal limits (CTmax ) and strongly associated with the potential temperatures of each thermal environment (operative temperatures during the potential period of breeding). This suggests that calling behaviour in ectotherms may take place at population-specific thermal ranges, diverging when species are subjected to distinct thermal environments, and might imply plasticity of thermal adjustment mechanisms (seasonal and developmental acclimation) that supply species with means of coping with climate change. Furthermore, the thermal thresholds of calling at the onset of the breeding season were dissimilar between conspecific populations, suggesting that other factors besides temperature are needed to trigger the onset of reproduction. Our

  10. Variations in global thunderstorm activity inferred from the OTD records

    NASA Astrophysics Data System (ADS)

    Nickolaenko, A. P.; Hayakawa, M.; Sekiguchi, M.

    2006-03-01

    We use the data on the planetary distribution of thunderstorms collected by optical transient detector (OTD) to derive the properties of global electric activity. Processing of optical data indicates that modern observations from space confirm the general concept of thunderstorm distribution and motion. Close similarity is demonstrated between the World Meteorological Organization data and modern records including Carnegie curve. Departures noted might be caused by thunderstorms redistribution owing to climate change; the issue deserves a special examination.

  11. The Impacts of Global Scale Climate Variations on Southwest Asia

    DTIC Science & Technology

    2006-03-01

    very sparse, and often falls in the form of convective showers , which often are difficult to predict. We split the six-month period of...solutions for heat induced tropical circulation. Quart. J. Roy. Meteor . Soc., 106, 447-462. Halpert, M. S., and C. F. Ropelewski, 1992: Surface...Coauthors, 1996: The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteor . Soc. 77, 437-471. Kiladis, G. N. and H. F. Diaz, 1989: Global

  12. Global variation in copy number in the human genome

    PubMed Central

    Redon, Richard; Ishikawa, Shumpei; Fitch, Karen R.; Feuk, Lars; Perry, George H.; Andrews, T. Daniel; Fiegler, Heike; Shapero, Michael H.; Carson, Andrew R.; Chen, Wenwei; Cho, Eun Kyung; Dallaire, Stephanie; Freeman, Jennifer L.; Gonzalez, Juan R.; Gratacos, Monica; Huang, Jing; Kalaitzopoulos, Dimitrios; Komura, Daisuke; MacDonald, Jeffrey R.; Marshall, Christian R.; Mei, Rui; Montgomery, Lyndal; Nishimura, Kunihiro; Okamura, Kohji; Shen, Fan; Somerville, Martin J.; Tchinda, Joelle; Valsesia, Armand; Woodwark, Cara; Yang, Fengtang; Zhang, Junjun; Zerjal, Tatiana; Zhang, Jane; Armengol, Lluis; Conrad, Donald F.; Estivill, Xavier; Tyler-Smith, Chris; Carter, Nigel P.; Aburatani, Hiroyuki; Lee, Charles; Jones, Keith W.; Scherer, Stephen W.; Hurles, Matthew E.

    2009-01-01

    Copy number variation (CNV) of DNA sequences is functionally significant but has yet to be fully ascertained. We have constructed a first-generation CNV map of the human genome through the study of 270 individuals from four populations with ancestry in Europe, Africa or Asia (the HapMap collection). DNA from these individuals was screened for CNV using two complementary technologies: single nucleotide polymorphism (SNP) genotyping arrays, and clone-based comparative genomic hybridization. 1,447 copy number variable regions covering 360 megabases (12% of the genome) were identified in these populations; these CNV regions contained hundreds of genes, disease loci, functional elements and segmental duplications. Strikingly, these CNVs encompassed more nucleotide content per genome than SNPs, underscoring the importance of CNV in genetic diversity and evolution. The data obtained delineate linkage disequilibrium patterns for many CNVs, and reveal dramatic variation in copy number among populations. We also demonstrate the utility of this resource for genetic disease studies. PMID:17122850

  13. Global variation in thermal tolerances and vulnerability of endotherms to climate change.

    PubMed

    Khaliq, Imran; Hof, Christian; Prinzinger, Roland; Böhning-Gaese, Katrin; Pfenninger, Markus

    2014-08-22

    The relationships among species' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals-a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species' physiology and the geography of climate change will advance assessments of species' vulnerability to climate change. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  14. Global variation in thermal tolerances and vulnerability of endotherms to climate change

    PubMed Central

    Khaliq, Imran; Hof, Christian; Prinzinger, Roland; Böhning-Gaese, Katrin; Pfenninger, Markus

    2014-01-01

    The relationships among species' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals—a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species' physiology and the geography of climate change will advance assessments of species' vulnerability to climate change. PMID:25009066

  15. Global analysis of phase variation in Myxococcus xanthus.

    PubMed

    Furusawa, Gou; Dziewanowska, Katarzyna; Stone, Hannah; Settles, Matthew; Hartzell, Patricia

    2011-08-01

    Myxococcus xanthus can vary its phenotype or 'phase' to produce colonies that contain predominantly yellow or tan cells that differ greatly in their abilities to swarm, survive and develop. Yellow variants are proficient at swarming (++) and tend to lyse in liquid during stationary phase. In contrast, tan variants are deficient in swarming (+) and persist beyond stationary phase. The phenotypes and transcriptomes of yellow and tan variants were compared with mutants affected in phase variation. Thirty-seven genes were upregulated specifically in yellow variants including those for production of the yellow pigment, DKxanthene. A mutant in DKxanthene synthesis produced non-pigmented (tan) colonies but still phase varied for swarming suggesting that pigmentation is not the cause of phase variation. Disruption of a gene encoding a HTH-Xre-like regulator, highly expressed in yellow variants, abolished pigment production and blocked the ability of cells to switch from a swarm ++ to a swarm (+) phenotype, showing that HTH-Xre regulates phase variation. Among the four genes whose expression was increased in tan variants was pkn14, which encodes a serine-threonine kinase that regulates programmed cell death in Myxococcus via the MrpC-MazF toxin-antitoxin complex. High levels of phosphorylated Pkn14 may explain why tan cells enjoy enhanced survival.

  16. Global analysis of phase variation in Myxococcus xanthus

    PubMed Central

    Furusawa, Gou; Dziewanowska, Katarzyna; Stone, Hannah; Settles, Matthew; Hartzell, Patricia

    2011-01-01

    SUMMARY Myxococcus xanthus can vary its phenotype or “phase” to produce colonies that contain predominantly yellow or tan cells that differ greatly in their abilities to swarm, survive, and develop. Yellow variants are proficient at swarming (++) and tend to lyse in liquid during stationary phase. In contrast, tan variants are deficient in swarming (+) and persist beyond stationary phase. The phenotypes and transcriptomes of yellow and tan variants were compared with mutants affected in phase variation. Thirty-seven genes were upregulated specifically in yellow variants including those for production of the yellow pigment, DKxanthene. A mutant in DKxanthene synthesis produced nonpigmented (tan) colonies but still phase varied for swarming suggesting that pigmentation is not the cause of phase variation. Disruption of a gene encoding a HTH-Xre-like regulator, highly expressed in yellow variants, abolished pigment production and blocked the ability of cells to switch from a swarm ++ to a swarm (+) phenotype, showing that HTH-Xre regulates phase variation. Among the four genes whose expression was increased in tan variants was pkn14, which encodes a serine-threonine kinase that regulates programmed cell death in Myxococcus via the MrpC-MazF toxin-antitoxin complex. High levels of phosphorylated Pkn14 may explain why tan cells enjoy enhanced survival. PMID:21722202

  17. Global-scale modes of surface temperature variability on interannual to century timescales

    NASA Technical Reports Server (NTRS)

    Mann, Michael E.; Park, Jeffrey

    1994-01-01

    Using 100 years of global temperature anomaly data, we have performed a singluar value decomposition of temperature variations in narrow frequency bands to isolate coherent spatio-temporal modes of global climate variability. Statistical significance is determined from confidence limits obtained by Monte Carlo simulations. Secular variance is dominated by a globally coherent trend; with nearly all grid points warming in phase at varying amplitude. A smaller, but significant, share of the secular variance corresponds to a pattern dominated by warming and subsequent cooling in the high latitude North Atlantic with a roughly centennial timescale. Spatial patterns associated with significant peaks in variance within a broad period range from 2.8 to 5.7 years exhibit characteristic El Nino-Southern Oscillation (ENSO) patterns. A recent transition to a regime of higher ENSO frequency is suggested by our analysis. An interdecadal mode in the 15-to-18 years period and a mode centered at 7-to-8 years period both exhibit predominantly a North Atlantic Oscillation (NAO) temperature pattern. A potentially significant decadal mode centered on 11-to-12 years period also exhibits an NAO temperature pattern and may be modulated by the century-scale North Atlantic variability.

  18. Global-scale modes of surface temperature variability on interannual to century timescales

    NASA Technical Reports Server (NTRS)

    Mann, Michael E.; Park, Jeffrey

    1994-01-01

    Using 100 years of global temperature anomaly data, we have performed a singluar value decomposition of temperature variations in narrow frequency bands to isolate coherent spatio-temporal modes of global climate variability. Statistical significance is determined from confidence limits obtained by Monte Carlo simulations. Secular variance is dominated by a globally coherent trend; with nearly all grid points warming in phase at varying amplitude. A smaller, but significant, share of the secular variance corresponds to a pattern dominated by warming and subsequent cooling in the high latitude North Atlantic with a roughly centennial timescale. Spatial patterns associated with significant peaks in variance within a broad period range from 2.8 to 5.7 years exhibit characteristic El Nino-Southern Oscillation (ENSO) patterns. A recent transition to a regime of higher ENSO frequency is suggested by our analysis. An interdecadal mode in the 15-to-18 years period and a mode centered at 7-to-8 years period both exhibit predominantly a North Atlantic Oscillation (NAO) temperature pattern. A potentially significant decadal mode centered on 11-to-12 years period also exhibits an NAO temperature pattern and may be modulated by the century-scale North Atlantic variability.

  19. Interannual Variation in Phytoplankton Primary Production at a Global Scale

    NASA Technical Reports Server (NTRS)

    Rousseaux, Cecile Severine; Gregg, Watson W.

    2013-01-01

    We used the NASA Ocean Biogeochemical Model (NOBM) combined with remote sensing data via assimilation to evaluate the contribution of four phytoplankton groups to the total primary production. First, we assessed the contribution of each phytoplankton groups to the total primary production at a global scale for the period 1998-2011. Globally, diatoms contributed the most to the total phytoplankton production ((is)approximately 50%, the equivalent of 20 PgC·y1). Coccolithophores and chlorophytes each contributed approximately 20% ((is) approximately 7 PgC·y1) of the total primary production and cyanobacteria represented about 10% ((is) approximately 4 PgC·y1) of the total primary production. Primary production by diatoms was highest in the high latitudes ((is) greater than 40 deg) and in major upwelling systems (Equatorial Pacific and Benguela system). We then assessed interannual variability of this group-specific primary production over the period 1998-2011. Globally the annual relative contribution of each phytoplankton groups to the total primary production varied by maximum 4% (1-2 PgC·y1). We assessed the effects of climate variability on group-specific primary production using global (i.e., Multivariate El Niño Index, MEI) and "regional" climate indices (e.g., Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO)). Most interannual variability occurred in the Equatorial Pacific and was associated with climate variability as indicated by significant correlation (p (is) less than 0.05) between the MEI and the group-specific primary production from all groups except coccolithophores. In the Atlantic, climate variability as indicated by NAO was significantly correlated to the primary production of 2 out of the 4 groups in the North Central Atlantic (diatoms/cyanobacteria) and in the North Atlantic (chlorophytes and coccolithophores). We found that climate variability as indicated by SAM had only a limited effect

  20. Upper Tropospheric Water Vapor and Cloud Variations with Sea Surface Temperature in Observations and Models

    NASA Astrophysics Data System (ADS)

    Su, H.; Park, J.; Shen, T. P. J.; Jiang, J. H.; Choi, Y. S.; Zhai, C.; Huang, L.

    2015-12-01

    Upper tropospheric water vapor and clouds (UTWVC) are critical to global radiative balance. The UTWVC variations with sea surface temperature (SST) are important components for climate feedbacks. In particular, the iris effect hypothesized by Lindzen et al. (2001) highlights that the radiative role of UTWVC is effective in relieving global warming. The iris effect and its implication for climate sensitivity and hydrological change (Mauritsen and Stevens 2015) center on the sign and magnitude of UTWVC with SST. We assess the UTWVC variations with SST using satellite observations and model simulations. The nearly 30-year observations of high cloud from the International Satellite Cloud Climatology Project and the over 10-year observations of UT water vapor, cloud and radiative fluxes from NASA's A-Train satellites are examined, in comparison with the counterparts in 14 CMIP5 models. We find that models underestimate the increase of outgoing longwave radiation with increasing SST compared to the observations, and this behavior is linked to the modeled UTWVC variations with SST. Across the 14 models, the ones with weaker iris effect tend to have higher equilibrium climate sensitivity.

  1. Imprints of climate forcings in global gridded temperature data

    NASA Astrophysics Data System (ADS)

    Mikšovský, Jiří; Holtanová, Eva; Pišoft, Petr

    2016-03-01

    Monthly near-surface temperature anomalies from several gridded data sets (GISTEMP, Berkeley Earth, MLOST, HadCRUT4, 20th Century Reanalysis) were investigated and compared with regard to the presence of components attributable to external climate forcings (associated with anthropogenic greenhouse gases, as well as solar and volcanic activity) and to major internal climate variability modes (El Niño/Southern Oscillation, North Atlantic Oscillation, Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation and variability characterized by the Trans-Polar Index). Multiple linear regression was used to separate components related to individual explanatory variables in local monthly temperatures as well as in their global means, over the 1901-2010 period. Strong correlations of temperature and anthropogenic forcing were confirmed for most of the globe, whereas only weaker and mostly statistically insignificant connections to solar activity were indicated. Imprints of volcanic forcing were found to be largely insignificant in the local temperatures, in contrast to the clear volcanic signature in their global averages. Attention was also paid to the manifestations of short-term time shifts in the responses to the forcings, and to differences in the spatial fingerprints detected from individual temperature data sets. It is shown that although the resemblance of the response patterns is usually strong, some regional contrasts appear. Noteworthy differences from the other data sets were found especially for the 20th Century Reanalysis, particularly for the components attributable to anthropogenic forcing over land, but also in the response to volcanism and in some of the teleconnection patterns related to the internal climate variability modes.

  2. Intensification of seasonal temperature extremes prior to the 2°C global warming target

    NASA Astrophysics Data System (ADS)

    Anderson, B. T.

    2011-12-01

    Given current international efforts to limit human-induced global-mean near-surface temperature increases to 2°C, relative to the pre-industrial era, there is an interest in determining what unavoidable impacts to physical, biological, and socio-economic systems might occur even if this target were met. In our research we show that substantial fractions of the globe could experience seasonal-mean temperature extremes with unprecedented regularity, even if the global-mean temperature remains below the 2°C target currently envisioned. These results have significant implications for agriculture and crop yield; disease and human health; and ecosystems and biodiversity. To obtain these results, we first develop a novel method for combining numerical-model estimates of near-term increases in grid-point temperatures with stochastically generated anomalies derived from high-resolution observations during the last half of the 20th century. This method has practical advantages because it generates results at fine spatial resolution without relying on computationally-intensive regional-model experiments; it explicitly incorporates information derived from the observations regarding interannual-to-decadal variations in seasonal-mean temperatures; and it includes the generation of thousands of realizations of the possible impacts of a global mean temperature increase on local occurrences of hot extremes. Using this method we find that even given the "committed" future global-mean temperature increase of 0.6°C (1.4°C relative to the pre-industrial era) historical seasonal-mean temperature extremes will be exceeded in at least half of all years-equivalently, the historical extreme values will become the norm-for much of Africa, the southeastern and central portions of Asia, Indonesia, and the Amazon. Should the global-mean temperature increase reach 2°C (relative to the pre-industrial era), it is more likely than not that these same regions, along with large portions of

  3. Temperature treatments during larval development reveal extensive heritable and plastic variation in gene expression and life history traits.

    PubMed

    Kvist, Jouni; Wheat, Christopher W; Kallioniemi, Eveliina; Saastamoinen, Marjo; Hanski, Ilkka; Frilander, Mikko J

    2013-02-01

    Little is known about variation in gene expression that affects life history traits in wild populations of outcrossing species. Here, we analyse heritability of larval development traits and associated variation in gene expression in the Glanville fritillary butterfly (Melitaea cinxia) across three ecologically relevant temperatures. We studied the development of final-instar larvae, which is greatly affected by temperature, and during which stage larvae build up most of the resources for adult life. Larval development time and weight gain varied significantly among families sampled from hundreds of local populations, indicating substantial heritable variation segregating in the large metapopulation. Global gene expression analysis using common garden-reared F2 families revealed that 42% of the >8000 genes surveyed exhibited significant variation among families, 39% of the genes showed significant variation between the temperature treatments, and 18% showed a significant genotype-by-environment interaction. Genes with large family and temperature effects included larval serum protein and cuticle-binding protein genes, and the expression of these genes was closely correlated with the rate of larval development. Significant expression variation in these same categories of genes has previously been reported among adult butterflies originating from newly established versus old local populations, supporting the notion of a life history syndrome put forward based on ecological studies and involving larval development and adult dispersal capacity. These findings suggest that metapopulation dynamics in heterogeneous environments maintain heritable gene expression variation that affects the regulation of life history traits.

  4. Intraspecific trait variation across scales: implications for understanding global change responses.

    PubMed

    Moran, Emily V; Hartig, Florian; Bell, David M

    2016-01-01

    Recognition of the importance of intraspecific variation in ecological processes has been growing, but empirical studies and models of global change have only begun to address this issue in detail. This review discusses sources and patterns of intraspecific trait variation and their consequences for understanding how ecological processes and patterns will respond to global change. We examine how current ecological models and theories incorporate intraspecific variation, review existing data sources that could help parameterize models that account for intraspecific variation in global change predictions, and discuss new data that may be needed. We provide guidelines on when it is most important to consider intraspecific variation, such as when trait variation is heritable or when nonlinear relationships are involved. We also highlight benefits and limitations of different model types and argue that many common modeling approaches such as matrix population models or global dynamic vegetation models can allow a stronger consideration of intraspecific trait variation if the necessary data are available. We recommend that existing data need to be made more accessible, though in some cases, new experiments are needed to disentangle causes of variation. © 2015 John Wiley & Sons Ltd.

  5. Diurnal variation in the effect of the weekend in global seismic activity

    NASA Astrophysics Data System (ADS)

    Ruzhin, Yu. Ya.; Chertoprud, V. E.; Ivanov-Kholodnyi, G. S.

    2016-09-01

    The influence of the earthquake probability diurnal variation on specific features in the weekend effect in global seismic activity is revealed. The dependence of the global earthquake number on the local time and its possible relation to a quiet solar diurnal variation ( Sq) in the geomagnetic field have been considered in detail. It has been indicated that a stable diurnal effect, which has a maximum near midnight and a minimum near local noon, exists in the global seismicity of the Earth. The diurnal variation amplitude changes insignificantly during days of week and substantially decreases (by a factor of almost 3) on Saturday and Sunday. The weekend effect is not revealed during "local nights." Since the daily effect of a quiet solar diurnal variation ( Sq) should not depend on days of week, we arrive at the conclusion that the diurnal variation in global seismicity evidently contains the anthropogenic activity product. The Sunday effect in the earthquake number decreases over the course of time and is most probably real but weak and not stationary since weekly variations occur against a background (or under the action) of stronger variations, i.e., an increase in the earthquake number and diurnal variations.

  6. Decadal climate variation recorded in modern global carbonate archives (brachiopods, molluscs)

    NASA Astrophysics Data System (ADS)

    Romanin, Marco; Zaki, Amir H.; Davis, Alyssa; Shaver, Kristen; Wang, Lisha; Aleksandra Bitner, Maria; Capraro, Luca; Preto, Nereo; Brand, Uwe

    2017-04-01

    The progress of the Earth's warming trend has rapidly accelerated in the last few decades due to the increase in emission of anthropogenic greenhouse gases. The exchange of heat between the atmosphere and seawater has consequently elevated the rate of temperature buildup in the low and high latitude ocean. Records of the variation in seawater temperature in response to local and global changes in climate are preserved within the carbonate structures of marine biogenic archives. Investigating the isotopic composition of the archives' growth increments documents the magnitude of sea surface temperature (SST) change. A long-term (1956-2012) record of temperature change in sub-tropical seawater was acquired from the giant clam Tridacna maxima collected from the Red Sea in conjunction with published results of the oyster Hyotissa hyotis (Titschack et al., 2010). Variation in polar-subpolar SST was obtained from the brachiopod Magellania venosa recovered from the coastal area of southern Chile, and from the proxy record of Hemithiris psittacea of Hudson Bay (Brand et al., 2014). The former reveals a long-term (1961-2012) time-series of Antarctic-induced oceanographic change in the southern hemisphere, while the latter represents a trend of Hudson Bay seawater SST in the northern hemisphere. Evaluation of the isotopic compositions confirms the equilibrium incorporation of oxygen isotopes with respect to ambient seawater in brachiopods and some bivalves. A general trend of decreasing δ18O values in the Red Sea molluscs is observed, indicating an increase in tropical seawater temperature of about 0.79°C since 1988. The δ18O values of the polar-subpolar brachiopods display similar depletion slopes but of larger magnitudes than that of the Red Sea archives. This signifies a rise in seawater temperature of about 1.47°C in Hudson Bay since 1991, and about 2.08°C in southern Chile since 1988. The 2013 IPCC report suggests an increase in SST of +0.094°C per decade (average

  7. Counter-Gradient Variation in Respiratory Performance of Coral Reef Fishes at Elevated Temperatures

    PubMed Central

    Gardiner, Naomi M.; Munday, Philip L.; Nilsson, Göran E.

    2010-01-01

    The response of species to global warming depends on how different populations are affected by increasing temperature throughout the species' geographic range. Local adaptation to thermal gradients could cause populations in different parts of the range to respond differently. In aquatic systems, keeping pace with increased oxygen demand is the key parameter affecting species' response to higher temperatures. Therefore, respiratory performance is expected to vary between populations at different latitudes because they experience different thermal environments. We tested for geographical variation in respiratory performance of tropical marine fishes by comparing thermal effects on resting and maximum rates of oxygen uptake for six species of coral reef fish at two locations on the Great Barrier Reef (GBR), Australia. The two locations, Heron Island and Lizard Island, are separated by approximately 1200 km along a latitudinal gradient. We found strong counter-gradient variation in aerobic scope between locations in four species from two families (Pomacentridae and Apogonidae). High-latitude populations (Heron Island, southern GBR) performed significantly better than low-latitude populations (Lizard Island, northern GBR) at temperatures up to 5°C above average summer surface-water temperature. The other two species showed no difference in aerobic scope between locations. Latitudinal variation in aerobic scope was primarily driven by up to 80% higher maximum rates of oxygen uptake in the higher latitude populations. Our findings suggest that compensatory mechanisms in high-latitude populations enhance their performance at extreme temperatures, and consequently, that high-latitude populations of reef fishes will be less impacted by ocean warming than will low-latitude populations. PMID:20949020

  8. Improvements of COMS Land Surface Temperature Retrieval Algorithm by considering diurnal variations of boundary layer temperature

    NASA Astrophysics Data System (ADS)

    Choi, Y. Y.; Suh, M. S.

    2015-12-01

    National Meteorological Satellite Centre in Republic of Korea retrieves operationally land surface temperature (LST) by applying the split-window LST algorithm (CSW_v1.0) from Communication, Ocean, and Meteorological Satellite (COMS) data. In order to improve COMS LST accuracy, Cho et al. (2015) developed six types of LST retrieval equations (CSW_v2.0) by considering temperature lapse rate and water vapor/aerosol effect. Similar to CSW_v1.0, the LST retrieved by CSW_v2.0 had a correlation coefficient of 0.99 with the prescribed LST and the root mean square error (RMSE) improved from 1.41 K to 1.39 K. However, CSW_v2.0 showed relatively poor performance, in particular, the temperature lapse rate is certainly large (superadiabatic cases during daytime or strong inversion cases during early morning). In this study, we upgraded the CSW_v2.0 by considering diurnal variations of boundary layer temperature to reduce the relatively large errors under the large lapse rate conditions. To achieve the goals, the diurnal variations of air temperature along with the land surface temperature are included during radiative transfer simulations for the generation of the pseudo-match-up database. The preliminary analysis results showed that RMSE and bias are reduced from 1.39K to 1.14K and from -0.03K to -0.01K. In this presentation, we will show the detailed results of LST retrieval using new algorithms according to the viewing geometry, temperature lapse rate condition, and water vapour amount along with the intercomparison results with MODIS LST data.

  9. Temperature Variations from HST Imagery and Spectroscopy of NGC 7009

    NASA Technical Reports Server (NTRS)

    Rubin, R. H.; Bhatt, N. J.; Dufour, R. J.; Buckalew, B. A.; Barlow, M. J.; Liu, X.-W.; Storey, P. J.; Balick, B.; Harrington, J. P.; Ferland, G. J.

    2002-01-01

    We present new HST/WFPC2 imagery and STIS long-slit spectroscopy of the planetary nebula NGC 7009. The primary goal was to obtain high spatial resolution of the intrinsic line ratio [O III] 4364/5008 and thereby evaluate the electron temperature (Te) and the mean-square Te variation (t(sup 2, sub A)) across the nebula. The observations here do not address Te fluctuation along the line of sight. The WFPC2 Te map is rather uniform; almost all values are between 9000 - 11,000 K, with the higher Te's closely coinciding with the inner He(++)-zone. The results indicate very small values - certainly less than 0.01 - for t(sup 2, sub A) throughout. Our STIS data allow an even more direct determination of Te and t(sup 2, sub A), albeit for a much smaller area than with WFPC2. We present results from binning the data along the slit into tiles that are 0.5 in square (matching the slit width). The average [O III] temperature using 45 tiles (excluding the central star and STIS fiducial bars) is 10,146 K; t(sup 2, sub A) is 0.0036. Although we have measured t(sup 2, sub A) in only 2-dimensions, we conclude that temperature fluctuations alone are unlikely to explain for NGC 7009 the large discrepancy between heavy element abundances inferred from emission lines that are collisionally excited compared with those that are due to recombination lines.

  10. Middle Pliocene sea surface temperatures: A global reconstruction

    USGS Publications Warehouse

    Dowsett, H.; Barron, J.; Poore, R.

    1996-01-01

    Identification and analyses of Pliocene marine microfossils from 64 globally distributed stratigraphic sequences have been used to produce a middle Pliocene sea surface temperature reconstruction of the Earth. This reconstruction shows little or no change from current conditions in low latitude regions and significant warming of the ocean surface at mid and higher latitudes of both hemispheres. This pattern of warming is consistent with terrestrial records and suggests a combination of enhanced meridional ocean heat transport and enhanced greenhouse effect were responsible for the middle Pliocene warmth.

  11. Patterns of Spatial Variation of Assemblages Associated with Intertidal Rocky Shores: A Global Perspective

    PubMed Central

    Cruz-Motta, Juan José; Miloslavich, Patricia; Palomo, Gabriela; Iken, Katrin; Konar, Brenda; Pohle, Gerhard; Trott, Tom; Benedetti-Cecchi, Lisandro; Herrera, César; Hernández, Alejandra; Sardi, Adriana; Bueno, Andrea; Castillo, Julio; Klein, Eduardo; Guerra-Castro, Edlin; Gobin, Judith; Gómez, Diana Isabel; Riosmena-Rodríguez, Rafael; Mead, Angela; Bigatti, Gregorio; Knowlton, Ann; Shirayama, Yoshihisa

    2010-01-01

    Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses. PMID:21179546

  12. Patterns of spatial variation of assemblages associated with intertidal rocky shores: a global perspective.

    PubMed

    Cruz-Motta, Juan José; Miloslavich, Patricia; Palomo, Gabriela; Iken, Katrin; Konar, Brenda; Pohle, Gerhard; Trott, Tom; Benedetti-Cecchi, Lisandro; Herrera, César; Hernández, Alejandra; Sardi, Adriana; Bueno, Andrea; Castillo, Julio; Klein, Eduardo; Guerra-Castro, Edlin; Gobin, Judith; Gómez, Diana Isabel; Riosmena-Rodríguez, Rafael; Mead, Angela; Bigatti, Gregorio; Knowlton, Ann; Shirayama, Yoshihisa

    2010-12-16

    Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses.

  13. Temperature, density, and composition in the disturbed thermosphere from Esro 4 gas analyzer measurements - A global model

    NASA Technical Reports Server (NTRS)

    Jacchia, L. G.; Slowey, J. W.; Von Zahn, U.

    1977-01-01

    An analysis of density measurements of Ar, N2, O, and He made at 280 km with the gas analyzer aboard the polar-orbiting satellite Esro 4 has yielded a global model of the variations in temperature, density, and composition that occur in the disturbed thermosphere. In the model the increase of temperature over quiet conditions is a nonlinear function of the planetary geomagnetic index, its latitude profile being approximated by a fourth-power sin phi law, where phi is the 'invariant' magnetic latitude. A density wave proceeding from high latitudes is approximated by a fourth power cos phi law. A strong nonlinearity in the relation between the temperature variations and the variations in the height of the homopause explains a previously found behavioral difference in the variation of atomic oxygen during magnetic storms and during periods of sustained geomagnetic activity.

  14. Fitting the observed changes of global surface temperatures

    NASA Astrophysics Data System (ADS)

    Courtillot, V.; Le Mouël, J.; Kossobokov, V. G.; Gibert, D.; Lopes, F.

    2012-12-01

    The quality of the fit of a trivial or, conversely, delicately-designed model to the observed natural phenomena is the fundamental pillar stone of any forecasting, including forecasting of the Earth's Climate. Using precise mathematical and logical systems outside their range of applicability can be scientifically groundless, unwise, and even dangerous. The temperature data sets are naturally in the basis of any hypothesizing on variability and forecasting the Earth's Climate. Leaving open the question of the global temperature definitions and their determination (T), we have analyzed hemispheric and global monthly temperature anomaly series produced by the Climate Research Unit of the University of East Anglia (CRUTEM4 database) and more recently by the Berkeley Earth Surface Temperature consortium (BEST database). We first fit the data in 1850-2010 with polynomials of degrees 1 to 9 and compare it with exponential fit by the adjusted R-squared criterion that takes into consideration the number of free parameters of the model. In all the cases considered, the adjusted R-squared values for polynomials are larger than for the exponential as soon as the degree exceeds 1 or 2. The polynomial fits become even more satisfactory as soon as degree 5 or 6 is reached. Extrapolations of these trends outside of the data domain show quick divergence. For example, the CRUTEM4vNH fit in the decade 2010-2020, for degrees 2 to 5, rises steeply then, for degrees 6 to 9, reverses to steep decreasing: the reversal in extrapolated trends arises from improved ability to fit the observed "~60-yr" wave in 150 years of data prior to 2010. The extrapolations prior to 1850 are even more erratic, linked with the increased dispersion of the early data. When focusing the analysis of fits on 1900-2010 we find that the apparent oscillations of T can be modeled by a series of linear segments: An optimal fit suggests 4 slope breaks indicating two clear transitions in 1940 and 1975, and two that

  15. A statistical light use efficiency model explains 85% variations in global GPP

    NASA Astrophysics Data System (ADS)

    Jiang, C.; Ryu, Y.

    2016-12-01

    Photosynthesis is a complicated process whose modeling requires different levels of assumptions, simplification, and parameterization. Among models, light use efficiency (LUE) model is highly compact but powerful in monitoring gross primary production (GPP) from satellite data. Most of LUE models adopt a multiplicative from of maximum LUE, absorbed photosynthetically active radiation (APAR), and temperature and water stress functions. However, maximum LUE is a fitting parameter with large spatial variations, but most studies only use several biome dependent constants. In addition, stress functions are empirical and arbitrary in literatures. Moreover, meteorological data used are usually coarse-resolution, e.g., 1°, which could cause large errors. Finally, sunlit and shade canopy have completely different light responses but little considered. Targeting these issues, we derived a new statistical LUE model from a process-based and satellite-driven model, the Breathing Earth System Simulator (BESS). We have already derived a set of global radiation (5-km resolution), carbon and water fluxes (1-km resolution) products from 2000 to 2015 from BESS. By exploring these datasets, we found strong correlation between APAR and GPP for sunlit (R2=0.84) and shade (R2=0.96) canopy, respectively. A simple model, only driven by sunlit and shade APAR, was thus built based on linear relationships. The slopes of the linear function act as effective LUE of global ecosystem, with values of 0.0232 and 0.0128 umol C/umol quanta for sunlit and shade canopy, respectively. When compared with MPI-BGC GPP products, a global proxy of FLUXNET data, BESS-LUE achieved an overall accuracy of R2 = 0.85, whereas original BESS was R2 = 0.83 and MODIS GPP product was R2 = 0.76. We investigated spatiotemporal variations of the effective LUE. Spatially, the ratio of sunlit to shade values ranged from 0.1 (wet tropic) to 4.5 (dry inland). By using maps of sunlit and shade effective LUE the accuracy of

  16. Global gyrokinetic ion temperature gradient turbulence simulations of ITER

    NASA Astrophysics Data System (ADS)

    Villard, L.; Angelino, P.; Bottino, A.; Brunner, S.; Jolliet, S.; McMillan, B. F.; Tran, T. M.; Vernay, T.

    2013-07-01

    Global gyrokinetic simulations of ion temperature gradient (ITG) driven turbulence in an ideal MHD ITER equilibrium plasma are performed with the ORB5 code. The noise control and field-aligned Fourier filtering procedures implemented in ORB5 are essential in obtaining numerically healthy results with a reasonable amount of computational effort: typical simulations require 109 grid points, 109 particles and, despite a particle per cell ratio of unity, achieve a signal to noise ratio larger than 50. As compared with a circular concentric configuration with otherwise similar parameters (same ρ* = 1/720), the effective heat diffusivity is considerably reduced for the ITER MHD equilibrium. A self-organized radial structure appears, with long-lived zonal flows (ZF), modulating turbulence heat transport and resulting in a corrugated temperature gradient profile. The ratio of long-lived ZF to the fluctuating ZF is markedly higher for the ITER MHD equilibrium as compared with circular configurations, thereby producing a more effective ITG turbulence suppression, in spite of a higher linear growth rate. As a result, the nonlinear critical temperature gradient, R/LTcrit,NL, is about twice the linear critical temperature gradient, R/LTcrit,lin. Moreover, the heat transport stiffness above the nonlinear threshold is considerably reduced as compared with circular cases. Plasma elongation is probably one of the essential causes of this behaviour: indeed, undamped ZF residual levels and geodesic acoustic mode damping are both increasing with elongation. Other possible causes of the difference, such as magnetic shear profile effects, are also investigated.

  17. Temporal variations in Global Seismic Stations ambient noise power levels

    USGS Publications Warehouse

    Ringler, A.T.; Gee, L.S.; Hutt, C.R.; McNamara, D.E.

    2010-01-01

    Recent concerns about time-dependent response changes in broadband seismometers have motivated the need for methods to monitor sensor health at Global Seismographic Network (GSN) stations. We present two new methods for monitoring temporal changes in data quality and instrument response transfer functions that are independent of Earth seismic velocity and attenuation models by comparing power levels against different baseline values. Our methods can resolve changes in both horizontal and vertical components in a broad range of periods (∼0.05 to 1,000 seconds) in near real time. In this report, we compare our methods with existing techniques and demonstrate how to resolve instrument response changes in long-period data (>100 seconds) as well as in the microseism bands (5 to 20 seconds).

  18. Pacific Sea Level Rise Patterns and Global Surface Temperature Variability

    NASA Astrophysics Data System (ADS)

    Yin, J.; Peyser, C.; Landerer, F. W.; Cole, J. E.

    2016-12-01

    During 1998-2012, climate change and sea level rise (SLR) exhibit two notable features: a slowdown of global surface warming (hiatus) and a rapid SLR in the tropical western Pacific. To quantify their relationship, we analyse the long-term control simulations of 38 climate models. We find a significant and robust correlation between the east-west contrast of dynamic sea level (DSL) in the Pacific and global mean surface temperature (GST) variability on both interannual and decadal time scales. Based on linear regression of the multi-model ensemble mean, the anomalously fast SLR in the western tropical Pacific observed during 1998-2012 indicates suppression of a potential global surface warming of 0.16o±0.06oC. In contrast, the Pacific contributed 0.29o±0.10oC to the significant interannual GST increase in 1997/98. The Pacific DSL anomalies observed in 2015 suggest that the strong El Niño in 2015/16 could lead to a 0.21o±0.07oC GST jump.

  19. Pacific sea level rise patterns and global surface temperature variability

    NASA Astrophysics Data System (ADS)

    Peyser, Cheryl E.; Yin, Jianjun; Landerer, Felix W.; Cole, Julia E.

    2016-08-01

    During 1998-2012, climate change and sea level rise (SLR) exhibit two notable features: a slowdown of global surface warming (hiatus) and a rapid SLR in the tropical western Pacific. To quantify their relationship, we analyze the long-term control simulations of 38 climate models. We find a significant and robust correlation between the east-west contrast of dynamic sea level (DSL) in the Pacific and global mean surface temperature (GST) variability on both interannual and decadal time scales. Based on linear regression of the multimodel ensemble mean, the anomalously fast SLR in the western tropical Pacific observed during 1998-2012 indicates suppression of a potential global surface warming of 0.16° ± 0.06°C. In contrast, the Pacific contributed 0.29° ± 0.10°C to the significant interannual GST increase in 1997/1998. The Pacific DSL anomalies observed in 2015 suggest that the strong El Niño in 2015/2016 could lead to a 0.21° ± 0.07°C GST jump.

  20. Broad-scale adaptive genetic variation in alpine plants is driven by temperature and precipitation

    PubMed Central

    MANEL, STÉPHANIE; GUGERLI, FELIX; THUILLER, WILFRIED; ALVAREZ, NADIR; LEGENDRE, PIERRE; HOLDEREGGER, ROLF; GIELLY, LUDOVIC; TABERLET, PIERRE

    2014-01-01

    Identifying adaptive genetic variation is a challenging task, in particular in non-model species for which genomic information is still limited or absent. Here, we studied distribution patterns of amplified fragment length polymorphisms (AFLPs) in response to environmental variation, in 13 alpine plant species consistently sampled across the entire European Alps. Multiple linear regressions were performed between AFLP allele frequencies per site as dependent variables and two categories of independent variables, namely Moran’s eigenvector map MEM variables (to account for spatial and unaccounted environmental variation, and historical demographic processes) and environmental variables. These associations allowed the identification of 153 loci of ecological relevance. Univariate regressions between allele frequency and each environmental factor further showed that loci of ecological relevance were mainly correlated with MEM variables. We found that precipitation and temperature were the best environmental predictors, whereas topographic factors were rarely involved in environmental associations. Climatic factors, subject to rapid variation as a result of the current global warming, are known to strongly influence the fate of alpine plants. Our study shows, for the first time for a large number of species, that the same environmental variables are drivers of plant adaptation at the scale of a whole biome, here the European Alps. PMID:22680783

  1. Global patterns of the trends in satellite-derived crop yield proxy, temperature and soil moisture

    NASA Astrophysics Data System (ADS)

    Sakai, T.; Iizumi, T.; Sakurai, G.; Okada, M.; Nishimori, M.

    2014-12-01

    Crop productivity (yield) is sensitive to climate variability and change. To inform stakeholders, including food agencies in food-importing countries, about future variations in food supply associated with climate variability and change, understanding major climatic drivers of the spatiotemporal variations in crop yield over global cropland during the last few decades is crucial. Although remote sensing has difficulty distinguishing individual crops and misses entire cropping cycles in areas where extensive cloud cover during the monsoon limits satellite observations, it is still useful in deriving a proxy of crop yield over large spatial domain and estimating the impacts on crop yield proxy due to climate, including land-surface temperature and surface-layer soil moisture. This study presents an attempt to globally depict the impact of climate change on crop yield proxy by applying a time series analysis to MODIS and AMSR-E satellite images. The crop yield proxy used was the annual maximum or integrated MODIS-derived NDVI during the growing period predefined on the basis of the global crop calendar. The trends in the crop yield proxy in the interval 2001-2013 appeared positive in higher latitudes and negative in lower latitudes. In higher latitudes (and thus colder regions), the increased land-surface temperature led to an increase in crop yield in part due to the enhanced photosynthesis rate. In contrast, the crop yield proxy showed negative correlation with land-surface temperature in lower latitudes. The increased temperature might decrease crop yield by increasing evapotranspiration rate, plant respiration and/or heat stress. The crop yield proxy was also correlated with the AMSR-E-derived soil moisture, although the geographical distribution of soil moisture was highly heterogeneous.

  2. Spatiotemporal analysis of temperature-variation patterns under climate change in the upper reach of Mekong River basin.

    PubMed

    Wu, Feifei; Wang, Xuan; Cai, Yanpeng; Yang, Zhifeng; Li, Chunhui

    2012-06-15

    Occurrence of temperature anomaly has greatly affected natural cycles of water resources in Lancang River basin in China, which is the upper reach of Mekong River. An integrated spatiotemporal decomposition and analysis method was proposed for the identification of temperature-variation patterns under changing climatic conditions in the basin. This method was based on the combination of S-mode empirical orthogonal function analysis, IDW interpolation, liner regression, weighted moving average and Mann Kendall methods. Results indicated that the first two modes extracted nearly 80% of spatiotemporal variations in temperature. Temperature in the whole basin followed the same variation trend through the first mode analysis. Sensitive areas were mainly located in the southwest of the basin, which occupied nearly half of the basin. The associated time series presented that the basin appeared transition from cold periods to warm periods. Temperature increased significantly over the period of 1960 to 2009 at annual and seasonal scales, particularly over 1990s. At the same time, the most significant rising occurred in winter and the least in summer. In the second mode, a west-east inverse phase pattern of temperature variations was a distinct feature in most of the basin. Temporal trend indicated that the increasing trend in the west region was slightly stronger than that in the east. This was particularly the case of edge areas almost vertical juncture with monsoons. This research is not only helpful in improving understanding of temperature response to global warming in the basin but also provides a basis for basin management.

  3. Resistivity Variation due to CO2 Migration in Different Temperature and Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Nakatsuka, Y.; Onishi, K.; Yamada, Y.; Matsuoka, T.; Xue, Z.

    2007-12-01

    CO2 geological sequestration is one of the effective approaches solving the global warming problem. Captured CO2 is injected to the deep aquifers or depleted oil and gas fields. Injected CO2 migrates thorough the reservoir rock, however, the details behavior of injected CO2 under the ground at super critical phase is not yet fully understood. Migration of injected CO2 will change by the condition of the injected reservoir such as the temperature and pressure. Also density and permeability of the rock may be changed due to temperature or pressure variations. These changes control the migration behavior of injected CO2. In this study, experiments of resistivity measurements were conducted to detect the migration difference of CO2 in different temperature and pressure conditions by using sandstone core samples. Core sample was taken from Berea sandstone and processed to 5cm diameter and 12cm length. For the resistivity measurement, impression electrode was set on the both end and the measurement electrode of ring condition was set on the side of the rock sample. We stetted the core sample in the pressure vessel and recreated the condition of underground reservoir which is high pressure and high temperature. We injected supercritical CO2 in different pressure and temperature for each experiment. Pressure was changed in range of 8 to 11MPa and temperature was changed in range of 35° to 45°. This means that all the experiments were conducted in supercritical phase. From the measured resistivity variation, we verified the migration of CO2 and compared the migration behavior of CO2 in different conditions.

  4. Analysis of trait mean and variability versus temperature in trematode cercariae: is there scope for adaptation to global warming?

    PubMed

    Studer, A; Poulin, R

    2014-05-01

    The potential of species for evolutionary adaptation in the context of global climate change has recently come under scrutiny. Estimates of phenotypic variation in biological traits may prove valuable for identifying species, or groups of species, with greater or lower potential for evolutionary adaptation, as this variation, when heritable, represents the basis for natural selection. Assuming that measures of trait variability reflect the evolutionary potential of these traits, we conducted an analysis across trematode species to determine the potential of these parasites as a group to adapt to increasing temperatures. Firstly, we assessed how the mean number of infective stages (cercariae) emerging from infected snail hosts as well as the survival and infectivity of cercariae are related to temperature. Secondly and importantly in the context of evolutionary potential, we assessed how coefficients of variation for these traits are related to temperature, in both cases controlling for other factors such as habitat, acclimatisation, latitude and type of target host. With increasing temperature, an optimum curve was found for mean output and mean infectivity, and a linear decrease for survival of cercariae. For coefficients of variation, temperature was only an important predictor in the case of cercarial output, where results indicated that there is, however, no evidence for limited trait variation at the higher temperature range. No directional trend was found for either variation of survival or infectivity. These results, characterising general patterns among trematodes, suggest that all three traits considered may have potential to change through adaptive evolution.

  5. Analyses of global sea surface temperature 1856-1991

    NASA Astrophysics Data System (ADS)

    Kaplan, Alexey; Cane, Mark A.; Kushnir, Yochanan; Clement, Amy C.; Blumenthal, M. Benno; Rajagopalan, Balaji

    1998-08-01

    Global analyses of monthly sea surface temperature (SST) anomalies from 1856 to 1991 are produced using three statistically based methods: optimal smoothing (OS), the Kaiman filter (KF) and optimal interpolation (OI). Each of these is accompanied by estimates of the error covariance of the analyzed fields. The spatial covariance function these methods require is estimated from the available data; the timemarching model is a first-order autoregressive model again estimated from data. The data input for the analyses are monthly anomalies from the United Kingdom Meteorological Office historical sea surface temperature data set (MOHSST5) [Parker et al., 1994] of the Global Ocean Surface Temperature Atlas (GOSTA) [Bottomley et al., 1990]. These analyses are compared with each other, with GOSTA, and with an analysis generated by projection (P) onto a set of empirical orthogonal functions (as in Smith et al. [1996]). In theory, the quality of the analyses should rank in the order OS, KF, OI, P, and GOSTA. It is found that the first four give comparable results in the data-rich periods (1951-1991), but at times when data is sparse the first three differ significantly from P and GOSTA. At these times the latter two often have extreme and fluctuating values, prima facie evidence of error. The statistical schemes are also verified against data not used in any of the analyses (proxy records derived from corals and air temperature records from coastal and island stations). We also present evidence that the analysis error estimates are indeed indicative of the quality of the products. At most times the OS and KF products are close to the OI product, but at times of especially poor coverage their use of information from other times is advantageous. The methods appear to reconstruct the major features of the global SST field from very sparse data. Comparison with other indications of the El Niño-Southern Oscillation cycle show that the analyses provide usable information on

  6. Impact of Atlantic sea surface temperatures on the warmest global surface air temperature of 1998

    NASA Astrophysics Data System (ADS)

    Lu, Riyu

    2005-03-01

    The year 1998 is the warmest year in the record of instrumental measurements. In this study, an atmospheric general circulation model is used to investigate the role of sea surface temperatures (SSTs) in this warmth, with a focus on the role of the Atlantic Ocean. The model forced with the observed global SSTs captures the main features of land surface air temperature anomalies in 1998. A sensitivity experiment shows that in comparison with the global SST anomalies, the Atlantic SST anomalies can explain 35% of the global mean surface air temperature (GMAT) anomaly, and 57% of the land surface air temperature anomaly in 1998. The mechanisms through which the Atlantic Ocean influences the GMAT are likely different from season to season. Possible detailed mechanisms involve the impact of SST anomalies on local convection in the tropical Atlantic region, the consequent excitation of a Rossby wave response that propagates into the North Atlantic and the Eurasian continent in winter and spring, and the consequent changes in tropical Walker circulation in summer and autumn that induce changes in convection over the tropical Pacific. This in turn affects climate in Asia and Australia. The important role of the Atlantic Ocean suggests that attention should be paid not only to the tropical Pacific Ocean, but also to the tropical Atlantic Ocean in understanding the GMAT variability and its predictability.

  7. Seasonal variations of global lightning activity extracted from Schumann resonances using a genetic algorithm method

    NASA Astrophysics Data System (ADS)

    Yang, Heng; Pasko, Victor P.; SáTori, Gabriella

    2009-01-01

    A three-dimensional Finite Difference Time Domain (FDTD) model of the Earth-ionosphere cavity with a realistic conductivity profile is employed to study the global lightning activity using the observed intensity variations of Schumann resonances (SR). Comparison of the results derived from our FDTD model and the previous studies by other authors on related subjects shows that Schumann resonance is a good probe to indicate the seasonal variations of lightning activity in three main thunderstorm regions (Africa, southeast Asia, and South America). An inverse method based on genetic algorithms is developed to extract information on lightning intensity in these three regions from observed SR intensity data. Seasonal variations of the lightning activity in three thunderstorm centers are clearly observed in our results. Different SR frequency variations associated with seasonal variations of global lighting activity are also discussed.

  8. Pressure variation of melting temperatures of alkali halides

    NASA Astrophysics Data System (ADS)

    Arafin, Sayyadul; Singh, Ram N.

    2017-02-01

    The melting temperatures of alkali halides (LiCl, LiF, NaBr, NaCl, NaF, NaI, KBr, KCl, KF, KI, RbBr, RbCl, RbI and CsI) have been evaluated over a wide range of pressures. The solid-liquid transition of alkali halides is of considerable significance due to their huge industrial applications. Our formalism requires a priori knowledge of the bulk modulus and the Grüneisen parameter at ambient conditions to compute Tm at high pressures. The computed values are in very good agreement with the available experimental results. The formalism can satisfactorily be used to compute Tm at high pressures where the experimental data are scanty. Most of the melting curves (Tm versus P) exhibit nonlinear variation with increasing pressure having curvatures downward and exhibit a maximum in some cases like NaCl, RbBr, RbCl and RbI. The values of Tmmax and Pmax corresponding to the maxima of the curves are given.

  9. On the Assessment of Global Terrestrial Reference Frame Temporal Variations

    NASA Astrophysics Data System (ADS)

    Ampatzidis, Dimitrios; Koenig, Rolf; Zhu, Shengyuan

    2015-04-01

    Global Terrestrial Reference Frames (GTRFs) as the International Terrestrial Reference Frame (ITRF) provide reliable 4-D position information (3-D coordinates and their evolution through time). The given 3-D velocities play a significant role in precise position acquisition and are estimated from long term coordinate time series from the space-geodetic techniques DORIS, GNSS, SLR, and VLBI. GTRFs temporal evolution is directly connected with their internal stability: The more intense and inhomogeneous velocity field, the less stable TRF is derived. The assessment of the quality of the GTRF is mainly realized by comparing it to each individual technique's reference frame. E.g the comparison of GTRFs to SLR-only based TRF gives the sense of the ITRF stability with respect to the Geocenter and scale and their associated rates respectively. In addition, the comparison of ITRF to the VLBI-only based TRF can be used for the scale validation. However, till now there is not any specified methodology for the total assessment (in terms of origin, orientation and scale respectively) of the temporal evolution and GTRFs associated accuracy. We present a new alternative diagnostic tool for the assessment of GTRFs temporal evolution based on the well-known time-dependent Helmert type transformation formula (three shifts, three rotations and scale rates respectively). The advantage of the new methodology relies on the fact that it uses the full velocity field of the TRF and therefore all points not just the ones common to different techniques. It also examines simultaneously rates of origin, orientation and scale. The methodology is presented and implemented to the two existing GTRFs on the market (ITRF and DTRF which is computed from DGFI) , the results are discussed. The results also allow to compare directly each GTRF dynamic behavior. Furthermore, the correlations of the estimated parameters can also provide useful information to the proposed GTRFs assessment scheme.

  10. Analyses Reveal Record-Shattering Global Warm Temperatures in 2015

    NASA Image and Video Library

    2016-01-20

    2015 was the warmest year since modern record-keeping began in 1880, according to a new analysis by NASA’s Goddard Institute for Space Studies. The record-breaking year continues a long-term warming trend — 15 of the 16 warmest years on record have now occurred since 2001. Credits: Scientific Visualization Studio/Goddard Space Flight Center Details: Earth’s 2015 surface temperatures were the warmest since modern record keeping began in 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA). Globally-averaged temperatures in 2015 shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 Celsius). Only once before, in 1998, has the new record been greater than the old record by this much. The 2015 temperatures continue a long-term warming trend, according to analyses by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York (GISTEMP). NOAA scientists agreed with the finding that 2015 was the warmest year on record based on separate, independent analyses of the data. Because weather station locations and measurements change over time, there is some uncertainty in the individual values in the GISTEMP index. Taking this into account, NASA analysis estimates 2015 was the warmest year with 94 percent certainty.

  11. Trends and associated uncertainty in the global mean temperature record

    NASA Astrophysics Data System (ADS)

    Poppick, A. N.; Moyer, E. J.; Stein, M.

    2016-12-01

    Physical models suggest that the Earth's mean temperature warms in response to changing CO2 concentrations (and hence increased radiative forcing); given physical uncertainties in this relationship, the historical temperature record is a source of empirical information about global warming. A persistent thread in many analyses of the historical temperature record, however, is the reliance on methods that appear to deemphasize both physical and statistical assumptions. Examples include regression models that treat time rather than radiative forcing as the relevant covariate, and time series methods that account for natural variability in nonparametric rather than parametric ways. We show here that methods that deemphasize assumptions can limit the scope of analysis and can lead to misleading inferences, particularly in the setting considered where the data record is relatively short and the scale of temporal correlation is relatively long. A proposed model that is simple but physically informed provides a more reliable estimate of trends and allows a broader array of questions to be addressed. In accounting for uncertainty, we also illustrate how parametric statistical models that are attuned to the important characteristics of natural variability can be more reliable than ostensibly more flexible approaches.

  12. Global variations in the uptake of single embryo transfer.

    PubMed

    Maheshwari, Abha; Griffiths, Siriol; Bhattacharya, Siladitya

    2011-01-01

    Single embryo transfer (SET) is the most effective way of reducing multiple pregnancy rates associated with assisted reproductive technology (ART). Despite published evidence suggesting that the judicious use of elective SET can lead to near-elimination of multiples without compromising cumulative live birth rates, the uptake of this strategy has been variable. Medline, EMBASE and the Cochrane Database of Systematic Reviews (1978-2010) were searched using appropriate MeSH headings. Leading fertility journals along with appropriate cross references were hand searched and information retrieved from national ART registers and websites of national fertility societies in order to determine current rates of SET. We explored social, economic and clinical factors determining the uptake of SET. It was not possible to distinguish elective from non-elective SET from national ART reports. Data from 31 countries suggest that there has been a gradual increase in SET rates over a 3 year period (2003-2005) but major geographical differences were noted. SET rates are highest in Sweden (69.4%) but are as low as 2.8% in the USA. Access to public funding for ART, availability of good cryopreservation facilities and legislation appear to be the most important reasons favouring the uptake of SET. Personal choice plays a significant role as many subfertile couples have a strong preference for twins. Awareness that double embryo transfer (DET) increases live birth per fresh treatment cycle, inability to accurately identify women at high risk for twins and limitations of existing embryos selection criteria are barriers to a wider acceptance of SET. The current variation in the uptake of elective SET is likely to persist until there are major changes in the way ART is viewed, funded and legislated.

  13. Estimation of surface temperature variations due to changes in sky and solar flux with elevation.

    USGS Publications Warehouse

    Hummer-Miller, S.

    1981-01-01

    Sky and solar radiance are of major importance in determining the ground temperature. Knowledge of their behavior is a fundamental part of surface temperature models. These 2 fluxes vary with elevation and this variation produces temperature changes. Therefore, when using thermal-property differences to discriminate geologic materials, these flux variations with elevation need to be considered. -from Author

  14. Global features of the semiannual oscillation in stratospheric temperatures and comparison between seasons and hemispheres

    NASA Technical Reports Server (NTRS)

    Gao, Xin-Hai; Yu, Wen-Bi; Stanford, John L.

    1987-01-01

    Four years of satellite-derived microwave and infrared radiances are analyzed for the three-dimensional and seasonal variation of semiannual oscillations (SAO) in stratospheric temperatures, with particular focus on high latitudes, to investigate the effect of stratospheric warmings on SAO. Separate analyses of individual seasons in each hemisphere reveal that the strongest SAO in temperature occur in the Northern Hemisphere (NH) winter polar upper stratosphere. These results, together with the latitudinal structure of the temperature SAO and the fact that the NH polar SAO is nearly out of phase with the lower latitude SAO, are consistent with the existence of a global-scale, meridional circulation on the SAO time scale. The results suggest that polar stratospheric warmings are an important source of SAO in both high and low latitude stratospheric temperature fields. Interannual variations, three-dimensional phase structure, and zonal asymmetry of SAO are also detailed. The SH stratospheric SAO is dominated by a localized feature in the high-latitude, eastern hemisphere which tilts westward with height.

  15. Global features of the semiannual oscillation in stratospheric temperatures and comparison between seasons and hemispheres

    NASA Technical Reports Server (NTRS)

    Gao, Xin-Hai; Yu, Wen-Bi; Stanford, John L.

    1987-01-01

    Four years of satellite-derived microwave and infrared radiances are analyzed for the three-dimensional and seasonal variation of semiannual oscillations (SAO) in stratospheric temperatures, with particular focus on high latitudes, to investigate the effect of stratospheric warmings on SAO. Separate analyses of individual seasons in each hemisphere reveal that the strongest SAO in temperature occur in the Northern Hemisphere (NH) winter polar upper stratosphere. These results, together with the latitudinal structure of the temperature SAO and the fact that the NH polar SAO is nearly out of phase with the lower latitude SAO, are consistent with the existence of a global-scale, meridional circulation on the SAO time scale. The results suggest that polar stratospheric warmings are an important source of SAO in both high and low latitude stratospheric temperature fields. Interannual variations, three-dimensional phase structure, and zonal asymmetry of SAO are also detailed. The SH stratospheric SAO is dominated by a localized feature in the high-latitude, eastern hemisphere which tilts westward with height.

  16. Correlation of solar irradiance and atmospheric temperature variations derived from spacecraft radiometry

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Bolden, William C.; Gibson, M. A.; Paden, Jack; Pandey, Dhirendra K.; Thomas, Susan; Wilson, Robert S.

    1992-01-01

    Long-term changes in the mean global atmospheric temperature and the total solar irradiance were examined utilizing 1979-1989 spacecraft measurements. Outgoing longwave radiation at the top of the atmosphere was employed to infer global atmospheric temperatures. Evidence was determined that indicates the global temperatures should decline in the 1990-1997 period as the magnitude of the incoming solar irradiance declines with decreasing solar magnetic activity.

  17. Subtle porosity variation in the YBa2Cu3O(7-x) high-temperature superconductor revealed by ultrasonic imaging

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Generazio, E. R.; Stang, D. B.; Hepp, A. F.

    1990-01-01

    The characterization of global porosity variation within a nominally 93-percent-dense specimen of YBa2Cu3O(7-x) high-temperature superconductor is reported. With a computer-controlled scanning system, precision ultrasonic velocity measurements were obtained at 100 micron increments over an 8- by 8-mm area of the YBa2Cu3O(7-x) specimen. The measurements were used to form a color map of velocity variation across the scanned region of the specimen. Subtle velocity variation on the order of 1 percent was observed. The specimen was shown by experimental methods to be single-phase, untextured, and free of nonuniform residual microstresses. From this knowledge and an established velocity-density relationship, a likely conclusion is that the observed velocity variations are solely due to porosity variations of similar magnitude. Locating these subtle porosity variations is critical since they can result in an order of magnitude variation in J(sub c) for dense YBCO specimens. Thus, mapping the global porosity distribution within YBa2Cu3O(7-x) may reveal regions that have poorer superconducting properties. Ultrasonic velocity results are translated into useful microstructural information for the material scientist.

  18. Long-Range Correlations of Global Sea Surface Temperature.

    PubMed

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870-2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities.

  19. Long-Range Correlations of Global Sea Surface Temperature

    PubMed Central

    Jiang, Lei; Zhao, Xia; Wang, Lu

    2016-01-01

    Scaling behaviors of the global monthly sea surface temperature (SST) derived from 1870–2009 average monthly data sets of Hadley Centre Sea Ice and SST (HadISST) are investigated employing detrended fluctuation analysis (DFA). The global SST fluctuations are found to be strong positively long-range correlated at all pertinent time-intervals. The value of scaling exponent is larger in the tropics than those in the intermediate latitudes of the northern and southern hemispheres. DFA leads to the scaling exponent α = 0.87 over the globe (60°S~60°N), northern hemisphere (0°N~60°N), and southern hemisphere (0°S~60°S), α = 0.84 over the intermediate latitude of southern hemisphere (30°S~60°S), α = 0.81 over the intermediate latitude of northern hemisphere (30°N~60°N) and α = 0.90 over the tropics 30°S~30°N [fluctuation F(s) ~ sα], which the fluctuations of monthly SST anomaly display long-term correlated behaviors. Furthermore, the larger the standard deviation is, the smaller long-range correlations (LRCs) of SST in the corresponding regions, especially in three distinct upwelling areas. After the standard deviation is taken into account, an index χ = α * σ is introduced to obtain the spatial distributions of χ. There exists an obvious change of global SST in central east and northern Pacific and the northwest Atlantic. This may be as a clue on predictability of climate and ocean variabilities. PMID:27100397

  20. Simple circuit provides adjustable voltage with linear temperature variation

    NASA Technical Reports Server (NTRS)

    Moede, L. W.

    1964-01-01

    A bridge circuit giving an adjustable output voltage that varies linearly with temperature is formed with temperature compensating diodes in one leg. A resistor voltage divider adjusts to temperature range across the bridge. The circuit is satisfactory over the temperature range of minus 20 degrees centigrade to plus 80 degrees centigrade.

  1. Long-range persistence in the global mean surface temperature and the global warming "time bomb"

    NASA Astrophysics Data System (ADS)

    Rypdal, M.; Rypdal, K.

    2012-04-01

    Detrended Fluctuation Analysis (DFA) and Maximum Likelihood Estimations (MLE) based on instrumental data over the last 160 years indicate that there is Long-Range Persistence (LRP) in Global Mean Surface Temperature (GMST) on time scales of months to decades. The persistence is much higher in sea surface temperature than in land temperatures. Power spectral analysis of multi-model, multi-ensemble runs of global climate models indicate further that this persistence may extend to centennial and maybe even millennial time-scales. We also support these conclusions by wavelet variogram analysis, DFA, and MLE of Northern hemisphere mean surface temperature reconstructions over the last two millennia. These analyses indicate that the GMST is a strongly persistent noise with Hurst exponent H>0.9 on time scales from decades up to at least 500 years. We show that such LRP can be very important for long-term climate prediction and for the establishment of a "time bomb" in the climate system due to a growing energy imbalance caused by the slow relaxation to radiative equilibrium under rising anthropogenic forcing. We do this by the construction of a multi-parameter dynamic-stochastic model for the GMST response to deterministic and stochastic forcing, where LRP is represented by a power-law response function. Reconstructed data for total forcing and GMST over the last millennium are used with this model to estimate trend coefficients and Hurst exponent for the GMST on multi-century time scale by means of MLE. Ensembles of solutions generated from the stochastic model also allow us to estimate confidence intervals for these estimates.

  2. Validation of the Global Land Data Assimilation System based on measurements of soil temperature profiles

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Li, Xiuping; Chen, Yingying; Yang, Kun; Chen, Deliang

    2016-04-01

    Soil temperature is a key parameter in the soil-vegetation-atmosphere system. It plays an important role in the land surface water and energy cycles, and has a major influence on vegetation growth and other hydrological aspects. We evaluated the accuracy of the soil temperature profiles from the Global Land Data Assimilation System (GLDAS) using nine observational networks across the world and aimed to find a reliable global soil temperature profile dataset for future hydrological and ecological studies. In general, the soil temperature profile data generated by the Noah model driven by the GLDAS forcing data (GLDAS_Noah10 and GLDAS_Noah10_v2) were found to have high skills in terms of daily, monthly, and mean seasonal variations, indicated by smaller bias and root-mean-square-error (RMSE) (both < 3 °C) and correlation coefficients larger than 0.90. Conversely, the Community Land Model (CLM) results (GLDAS_CLM10) generally showed larger bias and RMSE (both > 4°C). Further analysis showed that the overestimation by GLDAS_CLM10 was mainly caused by overestimation of the ground heat flux, determined by the thermal conductivity parameterization scheme, whereas the underestimation by GLDAS_Noah10 was due to underestimation of downward longwave radiation from the forcing data. Thus, more accurate forcing data should be required for the Noah model and an improved thermal parameterization scheme should be developed for the CLM. These approaches will improve the accuracy of simulated soil temperatures. To our knowledge, it is the first study to evaluate the GLDAS soil temperatures with comprehensive in situ observations across the world, and has a potential to facilitate an overall improvement of the GLDAS products (not only soil temperatures but also the related energy and water fluxes) as well as a refinement of the land surface parameterization used in GLDAS.

  3. Solar cycle variation of Mars exospheric temperatures: Critical review of available dayside measurements and recent model simulations

    NASA Astrophysics Data System (ADS)

    Bougher, Stephen; Huestis, David

    The responses of the Martian dayside thermosphere to solar flux variations (on both solar rotation and solar cycle timescales) have been the subject of considerable debate and study for many years. Available datasets include: Mariner 6,7,9 (UVS dayglow), Viking Lander 1-2 (UAMS densities upon descent), several aerobraking campaigns (MGS, Odyssey, MRO densities), and Mars Express (SPICAM dayglow). Radio Science derived plasma scale heights near the ionospheric peak can be used to derive neutral temperatures in this region (only); such values are not applicable to exobase heights (e.g. Forbes et al. 2008; Bougher et al. 2009). Recently, densities and temperatures derived from precise orbit determination of the MGS spacecraft (1999-2005) have been used to establish the responses of Mars' exosphere to long-term solar flux variations (Forbes et al., 2008). From this multi-year dataset, dayside exospheric temperatures weighted toward moderate southern latitudes are found to change by about 120 K over the solar cycle. However, the applicability of these drag derived exospheric temperatures to near solar minimum conditions is suspect (e.g Bruinsma and Lemoine, 2002). Finally, re-evaluation of production mechanisms for UV dayglow emissions implies revised values for exospheric temperatures (e.g. Simon et al., 2009; Huestis et al. 2010). Several processes are known to influence Mars' exospheric temperatures and their variability (Bougher et al., 1999; 2000; 2009). Solar EUV heating and its variations with solar fluxes received at Mars, CO2 15-micron cooling, molecular thermal conduction, and hydrodynamic heating/cooling associated with global dynamics all contribute to regulate dayside thermo-spheric temperatures. Poorly measured dayside atomic oxygen abundances render CO2 cooling rates uncertain at the present time. However, global thermospheric circulation models can be exercised for conditions spanning the solar cycle and Mars seasons to address the relative roles of

  4. A long-term association between global temperature and biodiversity, origination and extinction in the fossil record.

    PubMed

    Mayhew, Peter J; Jenkins, Gareth B; Benton, Timothy G

    2008-01-07

    The past relationship between global temperature and levels of biological diversity is of increasing concern due to anthropogenic climate warming. However, no consistent link between these variables has yet been demonstrated. We analysed the fossil record for the last 520 Myr against estimates of low latitude sea surface temperature for the same period. We found that global biodiversity (the richness of families and genera) is related to temperature and has been relatively low during warm 'greenhouse' phases, while during the same phases extinction and origination rates of taxonomic lineages have been relatively high. These findings are consistent for terrestrial and marine environments and are robust to a number of alternative assumptions and potential biases. Our results provide the first clear evidence that global climate may explain substantial variation in the fossil record in a simple and consistent manner. Our findings may have implications for extinction and biodiversity change under future climate warming.

  5. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, D.; Darvenzia, M.; Orville, R. E.; Williams, E. R.; Goodman, S. J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.

  6. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, D.; Darvenzia, M.; Orville, R. E.; Williams, E. R.; Goodman, S. J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.

  7. Joint spatiotemporal variability of global sea surface temperatures and global Palmer drought severity index values

    USGS Publications Warehouse

    Apipattanavis, S.; McCabe, G.J.; Rajagopalan, B.; Gangopadhyay, S.

    2009-01-01

    Dominant modes of individual and joint variability in global sea surface temperatures (SST) and global Palmer drought severity index (PDSI) values for the twentieth century are identified through a multivariate frequency domain singular value decomposition. This analysis indicates that a secular trend and variability related to the El Niño–Southern Oscillation (ENSO) are the dominant modes of variance shared among the global datasets. For the SST data the secular trend corresponds to a positive trend in Indian Ocean and South Atlantic SSTs, and a negative trend in North Pacific and North Atlantic SSTs. The ENSO reconstruction shows a strong signal in the tropical Pacific, North Pacific, and Indian Ocean regions. For the PDSI data, the secular trend reconstruction shows high amplitudes over central Africa including the Sahel, whereas the regions with strong ENSO amplitudes in PDSI are the southwestern and northwestern United States, South Africa, northeastern Brazil, central Africa, the Indian subcontinent, and Australia. An additional significant frequency, multidecadal variability, is identified for the Northern Hemisphere. This multidecadal frequency appears to be related to the Atlantic multidecadal oscillation (AMO). The multidecadal frequency is statistically significant in the Northern Hemisphere SST data, but is statistically nonsignificant in the PDSI data.

  8. The international surface temperature initiative's global land surface databank

    NASA Astrophysics Data System (ADS)

    Lawrimore, J. H.; Rennie, J.; Gambi de Almeida, W.; Christy, J.; Flannery, M.; Gleason, B.; Klein-Tank, A.; Mhanda, A.; Ishihara, K.; Lister, D.; Menne, M. J.; Razuvaev, V.; Renom, M.; Rusticucci, M.; Tandy, J.; Thorne, P. W.; Worley, S.

    2013-09-01

    The International Surface Temperature Initiative (ISTI) consists of an end-to-end process for land surface air temperature analyses. The foundation is the establishment of a global land surface Databank. This builds upon the groundbreaking efforts of scientists in the 1980s and 1990s. While using many of their principles, a primary aim is to improve aspects including data provenance, version control, openness and transparency, temporal and spatial coverage, and improved methods for merging disparate sources. The initial focus is on daily and monthly timescales. A Databank Working Group is focused on establishing Stage-0 (original observation forms) through Stage-3 data (merged dataset without quality control). More than 35 sources of data have already been added and efforts have now turned to development of the initial version of the merged dataset. Methods have been established for ensuring to the extent possible the provenance of all data from the point of observation through all intermediate steps to final archive and access. Databank submission procedures were designed to make the process of contributing data as easy as possible. All data are provided openly and without charge. We encourage the use of these data and feedback from interested users.

  9. Brief Communication: Correlation of global earthquake rates with temperature and sunspot cycle

    NASA Astrophysics Data System (ADS)

    Rajesh, R.; Tiwari, R. K.

    2014-04-01

    We studied the complex and non-stationary records of global earthquake employing the robust statistical and spectral techniques to understand the patterns, processes and periodicity. Singular Spectral Analysis (SSA) and correlation methods are used to quantify the nature of principle dynamical processes of global annual earthquake rates. The SSA decomposes the principle component of earthquake rates (first mode), which suggests that there is a linear increase in the yearly earthquake number from 1975 to 2005 accounting for 93% variance and may be identified with the earth's internal dynamical processes. Superimposed on this monotonic trend, there is an 11 years cyclic variation (second and third modes) accounting for 5% variance, which may corresponds to the well-known solar cycle. The remaining 2% higher order fluctuating components appears to be associated with artificial recharge and natural triggering forces (reservoir, tidal triggering etc.). The correlation study indicates that there is strong positive and negative correlation among the global earthquake rates with surface air temperature and sunspot numbers respectively. Interesting coupling mechanisms do exist, in which atmospheric circulations perturbed by the abrupt temperature variability might change the torques/momentum of inertia (earth's angular momentum) of the earth and thereby may offer the required inputs to trigger earthquake activities at the "critical phases".

  10. Response of Tropical Clouds to the Interannual Variation of Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    Fu, Rong; Liu, W. Timothy; Dickinson, Robert E.

    1996-01-01

    Connections between the large-scale interannual variations of clouds, deep convection, atmospheric winds. vertical thermodynamic structure, and SSTs over global tropical oceans are examined over the period July 1983 - December 1990. The SST warming associated with El Nino had a significant impact on the global tropical cloud field, although the warming itself was confined to the equatorial central and eastern Pacific. Extensive variations of the total cloud field occurred in the northeastern Indian, western and central Pacific, and western Atlantic Oceans. The changes of high and middle clouds dominated the total cloud variation in these regions. Total cloud variation was relatively weak in the eastern Pacific and the Atlantic because of the cancellation between the changes of high and low clouds. The variation of low clouds dominated the total cloud change in those areas. The destabilization of the lapse rate between 900 and 750 mb was more important for enhancing convective instability than was the change of local SSTs in the equatorial central Pacific during the 1997 El Nino. This destabilization is associated with anomalous rising motion in that region. As a result. convection and high and middle clouds increased in the equatorial central Pacific, In the subtropical Pacific, both the change of lapse rate between 900 and 750 mb associated A,ith anomalous subsidence and the decrease of boundary-layer buoyancy due to a decrease of temperature and moisture played an important role in enhancing convective stability. Consequently, convection, as well its high and middle clouds, decreased in these areas. The change ot'low clouds in the equatorial and southeastern Atlantic was correlated to both local SSTs and the SST changes in the equatorial eastern Pacific. In this area. the increase of low clouds was consistent with the sharper inversion during the 1987 El Nino, The strengthening of the inversion was not caused by a local SST change. although the local SST change

  11. Response of Tropical Clouds to the Interannual Variation of Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    Fu, Rong; Liu, W. Timothy; Dickinson, Robert E.

    1996-01-01

    Connections between the large-scale interannual variations of clouds, deep convection, atmospheric winds. vertical thermodynamic structure, and SSTs over global tropical oceans are examined over the period July 1983 - December 1990. The SST warming associated with El Nino had a significant impact on the global tropical cloud field, although the warming itself was confined to the equatorial central and eastern Pacific. Extensive variations of the total cloud field occurred in the northeastern Indian, western and central Pacific, and western Atlantic Oceans. The changes of high and middle clouds dominated the total cloud variation in these regions. Total cloud variation was relatively weak in the eastern Pacific and the Atlantic because of the cancellation between the changes of high and low clouds. The variation of low clouds dominated the total cloud change in those areas. The destabilization of the lapse rate between 900 and 750 mb was more important for enhancing convective instability than was the change of local SSTs in the equatorial central Pacific during the 1997 El Nino. This destabilization is associated with anomalous rising motion in that region. As a result. convection and high and middle clouds increased in the equatorial central Pacific, In the subtropical Pacific, both the change of lapse rate between 900 and 750 mb associated A,ith anomalous subsidence and the decrease of boundary-layer buoyancy due to a decrease of temperature and moisture played an important role in enhancing convective stability. Consequently, convection, as well its high and middle clouds, decreased in these areas. The change ot'low clouds in the equatorial and southeastern Atlantic was correlated to both local SSTs and the SST changes in the equatorial eastern Pacific. In this area. the increase of low clouds was consistent with the sharper inversion during the 1987 El Nino, The strengthening of the inversion was not caused by a local SST change. although the local SST change

  12. Inversion of gravity and bathymetry in oceanic regions for long-wavelength variations in upper mantle temperature and composition

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.; Jordan, Thomas H.

    1993-01-01

    Long-wavelength variations in geoid height, bathymetry, and SS-S travel times are all relatable to lateral variations in the characteristic temperature and bulk composition of the upper mantle. The temperature and composition are in turn relatable to mantle convection and the degree of melt extraction from the upper mantle residuum. Thus the combined inversion of the geoid or gravity field, residual bathymetry, and seismic velocity information offers the promise of resolving fundamental aspects of the pattern of mantle dynamics. The use of differential body wave travel times as a measure of seismic velocity information, in particular, permits resolution of lateral variations at scales not resolvable by conventional global or regional-scale seismic tomography with long-period surface waves. These intermediate scale lengths, well resolved in global gravity field models, are crucial for understanding the details of any chemical or physical layering in the mantle and of the characteristics of so-called 'small-scale' convection beneath oceanic lithosphere. In 1991 a three-year project to the NASA Geophysics Program was proposed to carry out a systematic inversion of long-wavelength geoid anomalies, residual bathymetric anomalies, and differential SS-S travel time delays for the lateral variation in characteristic temperature and bulk composition of the oceanic upper mantle. The project was funded as a three-year award, beginning on 1 Jan. 1992.

  13. Testing for the Possible Influence of Unknown Climate Forcings upon Global Temperature Increases from 1950-2000

    SciTech Connect

    Anderson, Bruce T.; Knight, Jeff R.; Ringer, Mark A.; Yoon, Jin-Ho; Cherchi, Annalisa

    2012-10-15

    Global-scale variations in the climate system over the last half of the twentieth century, including long-term increases in global-mean near-surface temperatures, are consistent with concurrent human-induced emissions of radiatively active gases and aerosols. However, such consistency does not preclude the possible influence of other forcing agents, including internal modes of climate variability or unaccounted for aerosol effects. To test whether other unknown forcing agents may have contributed to multidecadal increases in global-mean near-surface temperatures from 1950 to 2000, data pertaining to observed changes in global-scale sea surface temperatures and observed changes in radiatively active atmospheric constituents are incorporated into numerical global climate models. Results indicate that the radiative forcing needed to produce the observed long-term trends in sea surface temperatures—and global-mean near-surface temperatures—is provided predominantly by known changes in greenhouse gases and aerosols. Further, results indicate that less than 10% of the long-term historical increase in global-mean near-surface temperatures over the last half of the twentieth century could have been the result of internal climate variability. In addition, they indicate that less than 25%of the total radiative forcing needed to produce the observed long-term trend in global-mean near-surface temperatures could have been provided by changes in net radiative forcing from unknown sources (either positive or negative). These results, which are derived from simple energy balance requirements, emphasize the important role humans have played in modifying the global climate over the last half of the twentieth century.

  14. Estimating trends in the global mean temperature record

    NASA Astrophysics Data System (ADS)

    Poppick, Andrew; Moyer, Elisabeth J.; Stein, Michael L.

    2017-06-01

    Given uncertainties in physical theory and numerical climate simulations, the historical temperature record is often used as a source of empirical information about climate change. Many historical trend analyses appear to de-emphasize physical and statistical assumptions: examples include regression models that treat time rather than radiative forcing as the relevant covariate, and time series methods that account for internal variability in nonparametric rather than parametric ways. However, given a limited data record and the presence of internal variability, estimating radiatively forced temperature trends in the historical record necessarily requires some assumptions. Ostensibly empirical methods can also involve an inherent conflict in assumptions: they require data records that are short enough for naive trend models to be applicable, but long enough for long-timescale internal variability to be accounted for. In the context of global mean temperatures, empirical methods that appear to de-emphasize assumptions can therefore produce misleading inferences, because the trend over the twentieth century is complex and the scale of temporal correlation is long relative to the length of the data record. We illustrate here how a simple but physically motivated trend model can provide better-fitting and more broadly applicable trend estimates and can allow for a wider array of questions to be addressed. In particular, the model allows one to distinguish, within a single statistical framework, between uncertainties in the shorter-term vs. longer-term response to radiative forcing, with implications not only on historical trends but also on uncertainties in future projections. We also investigate the consequence on inferred uncertainties of the choice of a statistical description of internal variability. While nonparametric methods may seem to avoid making explicit assumptions, we demonstrate how even misspecified parametric statistical methods, if attuned to the

  15. Analyses Reveal Record-Shattering Global Warm Temperatures in 2015

    NASA Image and Video Library

    2017-09-28

    2015 was the warmest year since modern record-keeping began in 1880, according to a new analysis by NASA’s Goddard Institute for Space Studies. The record-breaking year continues a long-term warming trend — 15 of the 16 warmest years on record have now occurred since 2001. Credits: Scientific Visualization Studio/Goddard Space Flight Center Details: Earth’s 2015 surface temperatures were the warmest since modern record keeping began in 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA). Globally-averaged temperatures in 2015 shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 Celsius). Only once before, in 1998, has the new record been greater than the old record by this much. The 2015 temperatures continue a long-term warming trend, according to analyses by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York (GISTEMP). NOAA scientists agreed with the finding that 2015 was the warmest year on record based on separate, independent analyses of the data. Because weather station locations and measurements change over time, there is some uncertainty in the individual values in the GISTEMP index. Taking this into account, NASA analysis estimates 2015 was the warmest year with 94 percent certainty. Read more: www.nasa.gov/press-release/nasa-noaa-analyses-reveal-reco... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  16. Interannual climate variations in Arctic as driven by the Global atmosphere oscillation

    NASA Astrophysics Data System (ADS)

    Serykh, Ilya; Byshev, Vladimir; Neiman, Victor; Sidorova, Alexandra; Sonechkin, Dmitry

    2015-04-01

    The present-day global climate change affects the Arctic basin substantially more because of the sea ice cover extinction and the permafrost melting. But there are essential variations of these effects from year to year. We believe that these variations might be a regional manifestation of a planetary-scale phenomenon named the Global atmospheric oscillation (GAO). GAO includes the well-known El Niño - Southern Oscillation (ENSO) process and similar processes in equatorial Atlantic and Indian Oceans within itself. The goal of this report is to present some arguments to support this point of view. For this goal, we have studied some interrelations between the above-mentioned Arctic anomalies and GAO as seen in global re-analyses of the sea level pressure (SLP) and near surface temperature (NST) for the period of 1920-2013. The mean global fields of SLP and NST have been computed for all El Niño events falling into this time period, and separately, for all and La Niña events. As a result, two (for SLP and NST as well) global fields of the mean El Niño/La Niña difference were obtained. Statistical significance of the non-zero values of these fields, i.e. the reality of GAO, was evaluated with the t-Student's test. It turned out that the main spatial structures of GAO, presented specifically by El Niño and La Niña events in Pacific region, exist at a very high level (up to 99%, t>4) of the significance. Therefore, one can conclude that the interannual-scale dynamics of GAO is actually reflected in the climate features of different regions of the Earth, including the Russian Arctic. In particular, when the boreal winter season coincides with an El Niño event GAO is indicative by a negative anomaly of NST (about -1°C) and a positive anomaly of SLP over the Arctic basin. In contrary, significant (about +1°C) positive anomaly of NST along with reduced SLP over the whole Arctic region is typical for any La Niña event (up to 95%, t>2). To control the reliability

  17. A two-fold increase of carbon cycle sensitivity to tropical temperature variations.

    PubMed

    Wang, Xuhui; Piao, Shilong; Ciais, Philippe; Friedlingstein, Pierre; Myneni, Ranga B; Cox, Peter; Heimann, Martin; Miller, John; Peng, Shushi; Wang, Tao; Yang, Hui; Chen, Anping

    2014-02-13

    Earth system models project that the tropical land carbon sink will decrease in size in response to an increase in warming and drought during this century, probably causing a positive climate feedback. But available data are too limited at present to test the predicted changes in the tropical carbon balance in response to climate change. Long-term atmospheric carbon dioxide data provide a global record that integrates the interannual variability of the global carbon balance. Multiple lines of evidence demonstrate that most of this variability originates in the terrestrial biosphere. In particular, the year-to-year variations in the atmospheric carbon dioxide growth rate (CGR) are thought to be the result of fluctuations in the carbon fluxes of tropical land areas. Recently, the response of CGR to tropical climate interannual variability was used to put a constraint on the sensitivity of tropical land carbon to climate change. Here we use the long-term CGR record from Mauna Loa and the South Pole to show that the sensitivity of CGR to tropical temperature interannual variability has increased by a factor of 1.9 ± 0.3 in the past five decades. We find that this sensitivity was greater when tropical land regions experienced drier conditions. This suggests that the sensitivity of CGR to interannual temperature variations is regulated by moisture conditions, even though the direct correlation between CGR and tropical precipitation is weak. We also find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming.

  18. Reconstructing last 2000 years of temperature variation from Pyrenean caves (N Spain)

    NASA Astrophysics Data System (ADS)

    Moreno, Ana; Bartolomé, Miguel; Pérez, Carlos; Sancho, Carlos; Cacho, Isabel; Stoll, Heather; Delgado-Huertas, Antonio; Edwards, R. Lawrence; Cheng, Hai

    2016-04-01

    The Central Pyrenees, and particularly the protected area known as Ordesa and Monte Perdido National Park, is a high-altitude karstic region rich in cavities with active drips and present precipitation of carbonates. Although not generally very abundant, there are speleothems growths in several of those cavities. We present here (1) a three-year seasonal monitoring survey to isolate the environmental parameters influencing isotopic composition of farmed carbonate and (2) the last 2000 years isotopic record resulting from compiling seven stalagmites from three different caves. In temperate regions such as the NE Iberian Peninsula is difficult to discern the influences on δ18O variation in speleothems since temperature, amount of precipitation or even source effect are usually acting simultaneously. Main results after three years monitoring period indicate a strong dependence on air temperature through its influence on rainfall δ18O, although a small amount effect is not discarded. The good overlapping during the observational period of δ18O from actively growing modern stalagmites and air temperature in the area supports this dependence and provides a reliable proxy for the temperature evolution along last millennia. The stalagmites belong to three different caves (Seso, Gloces and B-1 caves) but still present a very coherent isotopic signal allowing us to discard local effects (diagenetic imprint, non-equilibrium fractionation) and to produce a stacked record with decadal resolution. Interpreting this signal as regional temperature variation divides the temporal sequence in five main periods, in consonance with historical stages. Thus, a continuous decrease in temperature characterized the end of the Roman period (0-500 AD). Lower temperatures are dominant during "Dark Ages" (500-1000 AD) that increase during the Medieval Climate Anomaly (MCA, 1000-1400 AD). Following this warm period, the cold signal during the Little Ice Age is very well replicated in several

  19. Temperature variation makes ectotherms more sensitive to climate change

    PubMed Central

    Paaijmans, Krijn P; Heinig, Rebecca L; Seliga, Rebecca A; Blanford, Justine I; Blanford, Simon; Murdock, Courtney C; Thomas, Matthew B

    2013-01-01

    Ectotherms are considered to be particularly vulnerable to climate warming. Descriptions of habitat temperatures and predicted changes in climate usually consider mean monthly, seasonal or annual conditions. Ectotherms, however, do not simply experience mean conditions, but are exposed to daily fluctuations in habitat temperatures. Here, we highlight how temperature fluctuation can generate ‘realized’ thermal reaction (fitness) norms that differ from the ‘fundamental’ norms derived under standard constant temperatures. Using a mosquito as a model organism, we find that temperature fluctuation reduces rate processes such as development under warm conditions, increases processes under cool conditions, and reduces both the optimum and the critical maximum temperature. Generalizing these effects for a range of terrestrial insects reveals that prevailing daily fluctuations in temperature should alter the sensitivity of species to climate warming by reducing ‘thermal safety margins’. Such effects of daily temperature dynamics have generally been ignored in the climate change literature. PMID:23630036

  20. Analysis of temperature distribution during tension test of glass fiber reinforced plastic by fiber orientation variation.

    PubMed

    Kim, Jin-Woo; Kim, Hyoung-Seok; Lee, Dong-Gi

    2014-10-01

    In this paper, analysis of temperature distribution by fiber orientation variation under tension test was proposed through IR thermography camera. Lock-in method, which is one of technique in IR thermography camera to measure minute change in temperature, was utilized to monitor temperature distribution and change during crack propagation. Method to analyze of temperature distribution by fiber orientation variation under tension test of GFRP via IR thermography camera was suggested. At the maximum stress point, temperature was significantly increased. As shown previously, specimen with shorter fracture time showed abrupt increment of temperature at the maximum stress point. Specimen with longer fracture time displayed increment of temperature after the maximum stress point.

  1. Temperature and compositional variations in the Australian cratons

    NASA Astrophysics Data System (ADS)

    Tesauro, Magdala; Kaban, Mikhail; Aitken, Alan; Kennett, Brian

    2017-04-01

    The upper mantle of the Australian continent has been deeply investigated in the last two decades using a variety of geophysical methods. The resulting models have revealed the robust large-scale features of the continental lithosphere of Australia, i.e., faster seismic velocities in the Archean and Proterozoic cratons in the West, North and South Australia and slower velocities in the eastern Phanerozoic margin. Furthermore, it has been identified a layered velocity structure in central Australia. The zone of low seismic velocities in the uppermost mantle is underlain by the high-velocity zone. This layered structure may have a thermal origin, due to a redistribution of high heat producing elements within the crust or reflect compositional changes, e.g. a presence of amphibole. To discern temperature and compositional variations in the Australian upper mantle, we apply an iterative technique, which employs a joint inversion of the seismic tomography and gravity data. This technique consists in removing the effect of the crust from the observed gravity field and topography. In the second step, the residual mantle gravity field and residual topography are inverted to obtain a 3-D density model of the upper mantle. The inversion technique accounts for the notion that these fields are controlled by the same factors but in a different way (e.g., depending on depth and horizontal dimension of the heterogeneity.) This enables us to locate the position of principal density anomalies in the upper mantle. Afterwards, the thermal contribution to the density structure is estimated by inverting the seismic tomography model AusREM (http://rses.anu.edu.au/seismology/AuSREM/index.php). Based on the residual fields, we construct an initial compositional model of the upper mantle. In particular, a negative residual density anomaly is interpreted as the material having a larger Mg# and depleted in garnet and CPX Then, the initial thermal model is re-estimated with the new

  2. Analysis and prediction of global climate temperature change based on multiforced observational statistics.

    PubMed

    Schönwiese, C D

    1994-01-01

    The response of the climate system to increasing greenhouse gases was simulated by a number of climate model projections. There is an urgent need to verify or falsify these projections against observational climate data. Therefore, in this contribution, surface air temperature data are considered covering on a global average the period 1861-1990 and on a northern hemisphere average 1670-1990 (including proxy data). Based on a multiple correlation and coherence analysis a regression model is evaluated which is simultaneously forced by the observed or reconstructed atmospheric CO(2) or equivalent CO(2) concentration increase, volcanic activity, solar variations, and the ENSO (El Niño/southern oscillation) mechanism including phase shifts between cause and effect. This model reveals a greenhouse-gas-induced mean global temperature rise of 0.6-0.8 K since preindustrial time (c. 1800-1990). Following the IPCC business-as-usual scenario (trend extrapolation) this would lead to a hypothetical 3.8 K temperature rise in 2100 (best estimate, uncertainty + 0.7/-0.4 K compared to the 1985 value.

  3. Influence of tropical wind on global temperature from months to decades

    NASA Astrophysics Data System (ADS)

    Saenko, Oleg A.; Fyfe, John C.; Swart, Neil C.; Lee, Warren G.; England, Matthew H.

    2016-10-01

    Using an Earth System Model and observations we analyze the sequence of events connecting episodes of trade wind strengthening (or weakening) to global mean surface temperature (GMST) cooling (or warming), with tropical ocean wave dynamics partially setting the time scale. In this sequence tropical west Pacific wind stress signals lead equatorial east Pacific thermocline depth signals which lead tropical east Pacific sea surface temperature (SST) signals which lead GMST signals. Using the anthropogenic, natural and tropical wind signals extracted from our simulations in a multivariate linear regression with observed GMST makes clear the balance that exists between anthropogenic warming and tropical wind-induced cooling during the recent warming slowdown, and between volcanic cooling and tropical wind-induced warming during the El Chichón and Pinatubo eruptions. Finally, we find an anticorrelation between global-mean temperatures in the near-surface (upper ˜ 100 m) and subsurface (˜ 100-300 m) ocean layers, linked to wind-driven interannual to decadal variations in the strength of the subtropical cell overturning in the upper Pacific Ocean.

  4. Temperature Effect in Secondary Cosmic Rays (MUONS) Observed at the Ground: Analysis of the Global MUON Detector Network Data

    NASA Astrophysics Data System (ADS)

    de Mendonça, R. R. S.; Braga, C. R.; Echer, E.; Dal Lago, A.; Munakata, K.; Kuwabara, T.; Kozai, M.; Kato, C.; Rockenbach, M.; Schuch, N. J.; Jassar, H. K. Al; Sharma, M. M.; Tokumaru, M.; Duldig, M. L.; Humble, J. E.; Evenson, P.; Sabbah, I.

    2016-10-01

    The analysis of cosmic ray intensity variation seen by muon detectors at Earth's surface can help us to understand astrophysical, solar, interplanetary and geomagnetic phenomena. However, before comparing cosmic ray intensity variations with extraterrestrial phenomena, it is necessary to take into account atmospheric effects such as the temperature effect. In this work, we analyzed this effect on the Global Muon Detector Network (GMDN), which is composed of four ground-based detectors, two in the northern hemisphere and two in the southern hemisphere. In general, we found a higher temperature influence on detectors located in the northern hemisphere. Besides that, we noticed that the seasonal temperature variation observed at the ground and at the altitude of maximum muon production are in antiphase for all GMDN locations (low-latitude regions). In this way, contrary to what is expected in high-latitude regions, the ground muon intensity decrease occurring during summertime would be related to both parts of the temperature effect (the negative and the positive). We analyzed several methods to describe the temperature effect on cosmic ray intensity. We found that the mass weighted method is the one that best reproduces the seasonal cosmic ray variation observed by the GMDN detectors and allows the highest correlation with long-term variation of the cosmic ray intensity seen by neutron monitors.

  5. Diurnal variation in temperature, mental and physical performance, and tasks specifically related to football (soccer).

    PubMed

    Reilly, Thomas; Atkinson, Greg; Edwards, Ben; Waterhouse, Jim; Farrelly, Kelly; Fairhurst, Emma

    2007-01-01

    Football (soccer) training and matches are scheduled at different times throughout the day. Association football involves a variety of fitness components as well as psychomotor and game-related cognitive skills. The purpose of the present research, consisting of two separate studies, was to determine whether game-related skills varied with time of day in phase with global markers of both performance and the body clock. In the first study, eight diurnally active male association football players (19.1+/-1.9 yrs of age; mean+/-SD) with 10.8+/-2.1 yrs playing experience participated. Measurements were made on different days at 08:00, 12:00, 16:00, and 20:00 h in a counterbalanced manner. Time-of-day changes in intra-aural temperature (used as a marker of the body clock), grip strength, reaction times, flexibility (markers of aspects of performance), juggling and dribbling tasks, and wall-volley test (football-specific skills) were compared. Significant (repeated measures analysis of variance, ANOVA) diurnal variations were found for body temperature (p<0.0005), choice reaction time (p<0.05), self-rated alertness (p<0.0005), fatigue (p<0.05), forward (sit-and-reach) flexibility (p<0.02), and right-hand grip strength (p<0.02), but not left-hand grip strength (p=0.40) nor whole-body (stand-and-reach) flexibility (p=0.07). Alertness was highest and fatigue lowest at 20:00 h. Football-specific skills of juggling performance showed significant diurnal variation (p<0.05, peak at 16:00 h), whereas performance on the wall-volley test tended to peak at 20:00 h and dribbling showed no time-of-day effect (p=0.55). In a second study, eight diurnally active subjects (23.0+/-0.7 yrs of age) completed five test sessions, at the same times as in the first study but with a second session at 08:00 h. Test-re-test comparisons at 08:00 h for all components indicated good reliability. Intra-aural temperature showed a significant time-of-day effect (p<0.001) with mean temperature at 16:00 h

  6. Cultivar variation in cotton photosynthetic performance under different temperature regimes

    USDA-ARS?s Scientific Manuscript database

    Cotton (Gossypium hirsutum L.) yields are impacted by overall photosynthetic production. Factors that influence crop photosynthesis are the plants genetic makeup and the environmental conditions. This study investigated cultivar variation in photosynthesis when plants were grown in the field under...

  7. Sahel Precipitation Variability and Global Sea Surface Temperature Forcing

    NASA Astrophysics Data System (ADS)

    Bach, D. E.; Kushnir, Y.; Seager, R.; Goddard, L.; Giannini, A.

    2003-12-01

    In the last 50 years or so, the Sahel region in sub-Saharan Africa has experienced two multi-decadal wet and dry periods separated by a relatively sharp transition. The onset of the dry episode in the Sahel is associated with the start of a significant warming trend in Southern Hemisphere sea surface temperatures (SST) that persisted well into the late 1990's. It has been stipulated, based on general circulation model (GCM) experiments, that the SST rise in the southern ocean basins is the predominant driver of rainfall patterns over the Sahel. Here we support this notion by comparing the observed rate of change in Southern Hemisphere SST with that of Sahel summertime rainfall. We examine the variations in each ocean basin separately and find that the drought pattern is most prominently associated with SST changes in the Indian Ocean, which display maximum warming rates simultaneously with the wet to dry shift in the Sahel. We provide further support to the role of the Indian Ocean using results from GCM integrations forced with observed Indian Ocean SST values and climatological values elsewhere, which effectively recreate the dry Sahel rainfall pattern. While the variations in equatorial Pacific SST associated with El Ni¤o have been found to have an effect on Sahel rainfall during the summer months, their influence does not appear to be significantly connected with the prolonged drought episode. The dry period was accentuated by two severe droughts in the early 1970's and 1980s, which generated very different repercussions for the Sahelian people. The first drought resulted in widespread famine and death while the second more severe drought in 1983-84 generated very few casualties. The political and socioeconomic assessment of these episodes suggests that the extensive loss of life was due to inefficient transportation of supplies to the starving populations. International aid organizations initiated famine protection programs following the 1970's drought that

  8. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming.

    PubMed

    Lin, Yong; Franzke, Christian L E

    2015-08-11

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary.

  9. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming

    PubMed Central

    Lin, Yong; Franzke, Christian L. E.

    2015-01-01

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary. PMID:26259555

  10. An Open and Transparent Databank of Global Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Rennie, J.; Thorne, P.; Lawrimore, J. H.; Gleason, B.; Menne, M. J.; Williams, C.

    2013-12-01

    The International Surface Temperature Initiative (ISTI) consists of an effort to create an end-to-end process for land surface air temperature analyses. The foundation of this process is the establishment of a global land surface databank. The databank builds upon the groundbreaking efforts of scientists who led efforts to construct global land surface datasets in the 1980's and 1990's. A primary aim of the databank is to improve aspects including data provenance, version control, temporal and spatial coverage, and improved methods for bringing dozens of source data together into an integrated dataset. The databank consists of multiple stages, with each successive stage providing a higher level of processing, quality and integration. Currently more than 50 sources of data have been added to the databank. An automated algorithm has been developed that merges these sources into one complete dataset by removing duplicate station records, identifying two or more station records that can be merged into a single record, and incorporating new and unique stations. The program runs iteratively through all the sources which are ordered based upon criteria established by the ISTI. The highest preferred source, known as the target, runs through all the candidate sources, calculating station comparisons that are acceptable for merging. The process is probabilistic in approach, and the final fate of a candidate station is based upon metadata matching and data equivalence criteria. If there is not enough information, the station is withheld for further investigation. The algorithm has been validated using a pseudo-source of stations with a known time of observation bias, and correct matches have been made nearly 95% of the time. The final product, endorsed and recommended by ISTI, contains over 30,000 stations, however slight changes in the algorithm can perturb results. Subjective decisions, such as the ordering of the sources, or changing metadata and data matching thresholds

  11. Modeling fish community dynamics in Florida Everglades: Role of temperature variation

    USGS Publications Warehouse

    Al-Rabai'ah, H. A.; Koh, H. L.; DeAngelis, Donald L.; Lee, Hooi-Ling

    2002-01-01

    The model shows that the temperature dependent starvation mortality is an important factor that influences fish population densities. It also shows high fish population densities at some temperature ranges when this consumption need is minimum. Several sensitivity analyses involving variations in temperature terms, food resources and water levels are conducted to ascertain the relative importance of temperature dependence terms.

  12. Impact of solar versus volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum

    NASA Astrophysics Data System (ADS)

    Anet, J. G.; Muthers, S.; Rozanov, E. V.; Raible, C. C.; Stenke, A.; Shapiro, A. I.; Brönnimann, S.; Arfeuille, F.; Brugnara, Y.; Beer, J.; Steinhilber, F.; Schmutz, W.; Peter, T.

    2014-05-01

    The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles versus volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, AD 1780-1840). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere-ocean chemistry-climate model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decreased global mean temperature by up to 0.5 K for 2-3 years after the eruption. However, while the volcanic effect is clearly discernible in the Southern Hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only an insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top-down processes (stemming from changes at λ < 250 nm) relative to bottom-up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease in the ocean heat content (OHC) between 0 and 300 m in depth, whereas the changes in irradiance at λ < 250 nm or in energetic particles have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing

  13. Impact of solar vs. volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum

    NASA Astrophysics Data System (ADS)

    Anet, J. G.; Muthers, S.; Rozanov, E. V.; Raible, C. C.; Stenke, A.; Shapiro, A. I.; Brönnimann, S.; Arfeuille, F.; Brugnara, Y.; Beer, J.; Steinhilber, F.; Schmutz, W.; Peter, T.

    2013-11-01

    The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles vs. volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, 1780-1840 AD). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere-ocean chemistry-climate-model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decrease global mean temperature by up to 0.5 K for 2-3 yr after the eruption. However, while the volcanic effect is clearly discernible in the southern hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree-ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top-down processes (stemming from changes at λ < 250 nm) relative to bottom-up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease of the ocean heat content (OHC) between the 0 and 300 m of depth, whereas the changes in irradiance at λ < 250 nm or in energetic particle have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing the OHC

  14. The influence of ocean surface temperature gradient and continentality on the Walker circulation. II - Prescribed global changes

    NASA Technical Reports Server (NTRS)

    Stone, P. H.; Chervin, R. M.

    1984-01-01

    The series of experiments presently used to investigate the mechanisms responsible for forcing the global Walker circulation features worldwide changes in ocean surface temperatures (OSTs), topography, and/or continents. The primary factor affecting circulation is noted to be the global distribution of continents and oceans; while OST gradients are also important, topography emerges as comparatively unimportant. Continentality and OST gradients force the model atmosphere through the introduction of zonal variations in surface heating. The vertical motions to which they give rise yield moisture convergence and condensation variations which reinforce vertical motions. The forcing by OST gradients is partly nonlocal, and the atmospheric response is effected by continentality. In all cases, vertical motion zonal variations correlate with precipitation.

  15. The influence of ocean surface temperature gradient and continentality on the Walker circulation. II - Prescribed global changes

    NASA Technical Reports Server (NTRS)

    Stone, P. H.; Chervin, R. M.

    1984-01-01

    The series of experiments presently used to investigate the mechanisms responsible for forcing the global Walker circulation features worldwide changes in ocean surface temperatures (OSTs), topography, and/or continents. The primary factor affecting circulation is noted to be the global distribution of continents and oceans; while OST gradients are also important, topography emerges as comparatively unimportant. Continentality and OST gradients force the model atmosphere through the introduction of zonal variations in surface heating. The vertical motions to which they give rise yield moisture convergence and condensation variations which reinforce vertical motions. The forcing by OST gradients is partly nonlocal, and the atmospheric response is effected by continentality. In all cases, vertical motion zonal variations correlate with precipitation.

  16. Global Observations of Exospheric Temperature During the Bastille Day Event and Comparisons With the MTIEGCM Model and NRLMSIS-2000

    NASA Astrophysics Data System (ADS)

    Dymond, K. F.; Budzien, S. A.; McCoy, R. P.; Crowley, G.

    2005-12-01

    We present observations of the global exospheric temperature and its variation during the Bastille Day geomagnetic storm that occurred on July 14-18, 2000. The Bastiile Day event was initiated by an X-class solar flare that was followed by a coronal mass ejection. The CME eventually produced a major geomagnetic storm. Global exospheric temperatures were derived by fitting the topside intensity distribution of limb scan data observed by the Low Resolution Airglow and Aurora Spectrograph (LORAAS) on the Advanced Research and Global Observation Satellite (ARGOS). The ARGOS was launched into a sun-synchronous orbit on 23 February 1999 at 2:29:55 AM Pacific Standard Time. The LORAAS obtained limb scans every 90 seconds providing soundings spaced by approximately 5.4° of latitude. We compare the LORAAS-derived exospheric temperatures with exospheric temperatures predicted by the Mass Spectrometer and Incoherent Scatter (MSIS) with Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (MTIEGCM). We find that the measured temperatures are systematically higher, by ~200 K, than predicted by the NRLMSIS-2000 model and the temporal evolution of the temperature changes is also not well reproduced by the model. The MTIEGCM model, with its more accurate picture of the geomagnetic and solar effects, is shown to better capture both the time evolution of the storm-time temperature changes and to also more accurately predict the quiet time temperatures.

  17. Variation in rhinarium temperature indicates sensory specializations in placental mammals.

    PubMed

    Gläser, Nele; Kröger, Ronald H H

    2017-07-01

    The rhinarium, a specialized nose-tip characterized by an area of naked and wet skin around the nostrils, is a typical mammalian structure. The type and amount of innervation suggests a sensory role and morphological diversity implies so far unidentified species-specific functional specializations. Rhinaria also vary in temperature and this may be related to the functions of these sensory organs. We performed a comparative study on rhinarium temperature in order to learn more about possible correlations with phylogeny and ecology. We have concentrated on terrestrial carnivorans and large herbivores, but also investigated a number of other species, some of them lacking typical rhinaria. We used infrared (IR) thermography to determine nose skin temperatures from safe distances and without interfering with the animals' behavior. In all groups studied, the temperature of the rhinarium/nose-tip decreased with decreasing ambient temperature. At all ambient temperatures, rhinarium temperature was lower, by 9-17°C, in carnivorans compared to herbivores. Glires (rodents and lagomorphs), haplorrhine primates, and omnivorous Perisso- and Artiodactyla were intermediate. In strepsirrhine primates, rhinarium temperature was similar to ambient temperature. Our findings in Strepsirrhini are consistent with the hypothesis that their rhinaria have an indirect role in chemical communication. Warm rhinaria in herbivores suggest a tactile function, while the low skin temperatures on carnivoran rhinaria may make the skin particularly sensitive to warming. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Recent variations of sea ice and air temperature in high latitudes

    SciTech Connect

    Chapman, W.L.; Walsh, J.E. )

    1993-01-01

    Feedbacks resulting from the retreat of sea ice and snow contribute to the polar amplification of the greenhouse warming projected by global climate models. A gridded sea-ice database, for which the record length is now approaching four decades for the Arctic and two decades for the Antarctic, is summarized here. The sea-ice fluctuations derived from the data set are characterized by (1) temporal scales of several seasons to several years and (2) spatial scales of 30[degrees]-180[degrees] of longitude. The ice data are examined in conjunction with air temperature data for evidence of recent climate change in the polar regions. The arctic sea-ice variations over the past several decades are compatible with the corresponding air temperatures, which show a distinct warming that is strongest over northern land areas during the winter and spring. The temperature trends over the sub arctic seas are smaller and even negative in the southern Greenland region. Statistically significant decreases of the summer extent of arctic ice are apparent in the sea-ice data, and new summer minima have been achieved three times in the past 15 years. There is no significant trend of ice extent in the Arctic during winter or in the Antarctic during any season. The seasonal and geographical changes of sea-ice coverage are consistent with the more recent greenhouse experiments performed with coupled atmosphere-ocean models.

  19. Submillimeter Observations of Global Variations in Chemistry and Dynamics in the Venus Mesosphere

    NASA Astrophysics Data System (ADS)

    Clancy, R. T.; Sandor, B. J.; Moriarty-Schieven, G.

    2005-08-01

    Circulation and photochemical behaviors of the Venus middle atmosphere (mesosphere, 65-105 km altitudes) exhibit remarkable temporal variations that are often defined by ground-based studies. Sub-millimeter spectral line observations in particular play and important role in the investigation of the Venus mesosphere due to relatively strong transitions for CO, HDO, SO2, and SO in the wavelength region and the pressure-broadened lineshapes of these absorptions. Venus nightside sub-millimeter 12CO spectra (345 GHz) exhibit sharp, deep absorption cores that yield excellent temperature weighting functions about the Venus mesopause (Clancy et al., 2003) and maximum sensitivity to Doppler line shifts, a modest 10 m/sec line-of-sight wind is easily detectable in short integrations (5-10 minutes). An accumulated set of James Clerk Maxwell Telescope (JCMT) observations during Venus inferior conjunctions in 2000, 2002, and 2004 provide nightside mapping of Doppler winds, CO, and temperatures over the 95-105 km altitude region. The nightside distribution of winds varies over all observed timescales. For periods separated by one week, the Venus nightside global circulation changes character for zonal rotation to subsolar-to-antisolar (SS-AS) flow. On hourly timescales, wind velocities may vary by > 50 m/sec over 3000 km spatial scales. The instantaneous nightside circulation field is extremely asymmetric in latitude and local time. During the June 2004 inferior conjunction of Venus, we also obtained the first detection of mesospheric SO2 and a very sensitive upper limit for SO; indicating Venus mesospheric SO2 abundances roughly twice that predicted by the preferred photochemical model of Yung and DeMore (1982), and an SO2/SO ratio at least 8 times the same model predictions. These departures from the model are probably due in large part to the fixed water vapor abundance of 1 ppmv throughout the Venus mesosphere, employed in the Yung and DeMore model for lack of data. As an

  20. Global Electric Circuit Diurnal Variation Derived from Storm Overflight and Satellite Optical Lightning Datasets

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, R. J.; Bateman, M. J.; Bailey, J. C.

    2011-01-01

    We have combined analyses of over 1000 high altitude aircraft observations of electrified clouds with diurnal lightning statistics from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) to produce an estimate of the diurnal variation in the global electric circuit. Using basic assumptions about the mean storm currents as a function of flash rate and location, and the global electric circuit, our estimate of the current in the global electric circuit matches the Carnegie curve diurnal variation to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Mean contributions to the global electric circuit from land and ocean thunderstorms are 1.1 kA (land) and 0.7 kA (ocean). Contributions to the global electric circuit from ESCs are 0.22 kA for ocean storms and 0.04 kA for land storms. Using our analysis, the mean total conduction current for the global electric circuit is 2.0 kA.

  1. Changes of the Oceanic Long-term and seasonal variation in a Global-warming Climate

    NASA Astrophysics Data System (ADS)

    Xia, Q.; He, Y.; Dong, C.

    2015-12-01

    Abstract: Gridded absolute dynamic topography (ADT) from AVISO and outputs of sea surface height above geoid from a series of climate models run for CMIP5 are used to analysis global sea level variation. Variance has been calculated to determine the magnitude of change in sea level variation over two decades. Increasing trend of variance of ADT suggests an enhanced fluctuation as well as geostrophic shear of global ocean. To further determine on what scale does the increasing fluctuation dominate, the global absolute dynamic topography (ADT) has been separated into two distinguished parts: the global five-year mean sea surface (MSS) and the residual absolute dynamic topography (RADT). Increased variance of MSS can be ascribed to the nonuniform rising of global sea level and an enhancement of ocean gyres in the Pacific Ocean. While trend in the variance of RADT is found to be close to zero which suggests an unchanged ocean mesoscale variability. The Gaussian-like distribution of global ADT are used to study the change in extreme sea levels. Information entropy has also been adapted in our study. Increasing trend of information entropy which measures the degree of dispersion of a probability distribution suggests more appearance of extreme sea levels. Extreme high sea levels are increasing with a higher growing rate than the mean sea level rise.

  2. An improved global zenith tropospheric delay model GZTD2 considering diurnal variations

    NASA Astrophysics Data System (ADS)

    Yao, Yibin; Hu, Yufeng; Yu, Chen; Zhang, Bao; Guo, Jianjian

    2016-05-01

    The zenith tropospheric delay (ZTD) is an important atmospheric parameter in the wide application of global navigation satellite systems (GNSS) technology in geoscience. Given that the temporal resolution of the current global zenith tropospheric delay model (GZTD) is only 24 h, an improved model, GZTD2, has been developed by taking the diurnal variations into consideration and modifying the model expansion function. The data set used to establish this model is the global ZTD grid data provided by Global Geodetic Observing System (GGOS) Atmosphere spanning from 2002 to 2009. We validated the proposed model with respect to ZTD grid data from GGOS Atmosphere, which was not involved in modeling, as well as International GNSS Service (IGS) tropospheric product. The obtained results of ZTD grid data show that the global average bias and root mean square (rms) for the GZTD2 model are 0.2 and 3.8 cm, respectively. The global average bias is comparable to that of the GZTD model, but the global average rms is improved by 3 mm. The bias and rms are far better than the EGNOS model and the UNB series models. The testing results from global IGS tropospheric product show the bias and rms (-0.3 and 3.9 cm) of the GZTD2 model are superior to that of GZTD (-0.3 and 4.2 cm), suggesting higher accuracy and reliability compared to the EGNOS model, as well as the UNB series models.

  3. Variation of Azeotropic Composition and Temperature with Pressure

    ERIC Educational Resources Information Center

    Gibbard, H. Frank; Emptage, Michael R.

    1975-01-01

    Describes an undergraduate physical chemistry experiment in which an azeotropic mixture is studied using the vapor pressures of the components as functions of temperature and the azeotropic composition and temperature at one pressure. Discusses in detail the mathematical treatment of obtained thermodynamic data. (MLH)

  4. Antarctic Sea ice variations and seasonal air temperature relationships

    NASA Technical Reports Server (NTRS)

    Weatherly, John W.; Walsh, John E.; Zwally, H. J.

    1991-01-01

    Data through 1987 are used to determine the regional and seasonal dependencies of recent trends of Antarctic temperature and sea ice. Lead-lag relationships involving regional sea ice and air temperature are systematically evaluated, with an eye toward the ice-temperature feedbacks that may influence climatic change. Over the 1958-1087 period the temperature trends are positive in all seasons. For the 15 years (l973-l987) for which ice data are available, the trends are predominantly positive only in winter and summer, and are most strongly positive over the Antarctic Peninsula. The spatially aggregated trend of temperature for this latter period is small but positive, while the corresponding trend of ice coverage is small but negative. Lag correlations between seasonal anomalies of the two variables are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures. The implication is that summer temperatures predispose the near-surface waters to above-or below-normal ice coverage in the following fall and winter.

  5. The Seasonal and Diurnal Variations of Lower and Middle Atmosphere Temperatures at the South Pole

    NASA Astrophysics Data System (ADS)

    Chu, X.; Pan, W.; Gardner, C. S.

    2001-05-01

    An Fe Boltzmann Temperature Lidar was operated at the Amundsen-Scott South Pole Station from 1999-2001. Temperature profiles were obtained by combining the lidar data from 30-75 km and the balloon data from ground to around 35 km. We summarize the seasonal variations of the troposphere up to mesosphere temperatures at the South Pole. Furthermore, more than 24 hours continuous lidar observations at the South Pole allow us to study the diurnal variations of the stratosphere temperatures. We also present the seasonal and diurnal variations of the mesospheric Fe densities, which indicate the effects of Fe chemistry and the persistent oscillations at the South Pole.

  6. Temperature Variations in Lubricating Films Induced by Viscous Dissipation

    NASA Astrophysics Data System (ADS)

    Mozaffari, Farshad; Metcalfe, Ralph

    2015-11-01

    We have studied temperature distributions of lubricating films. The study has applications in tribology where temperature-reduced viscosity decreases load carrying capacity of bearings, or degrades elastomeric seals. The viscosity- temperature dependency is modeled according to ASTM D341-09. We have modeled the film temperature distribution by our finite element program. The program is made up of three modules: the first one solves the general form of Reynolds equation for the film pressure and velocity gradients. The other two solve the energy equation for the film and its solid boundary temperature distributions. The modules are numerically coupled and iteratively converged to the solutions. We have shown that the temperature distribution in the film is strongly coupled with the thermal response at the boundary. In addition, only thermal diffusion across film thickness is dominant. Moreover, thermal diffusion in the lateral directions, as well as all the convection terms, are negligible. The approximation reduces the energy equation to an ordinary differential equation, which significantly simplifies the modeling of temperature -viscosity effects in thin films. Supported by Kalsi Engineering, Inc.

  7. Global Snow Cover Estimation with Microwave Brightness Temperature Measurements and One-Class in situ Observations

    NASA Astrophysics Data System (ADS)

    Xu, X.; Liu, X.; Li, X.; Shi, Q.

    2016-12-01

    Brightness temperature (BT), which is remotely sensed by the space-borne microwave radiometer, is widely used in snow cover monitoring for its long time series imaging capabilities in all-weather conditions. Traditional linear fitting and stand-alone methods are usually uncertain with respect to the spatial distribution and temporal variation of derived snow cover, as they rarely consider local conditions and scene characteristics but fit the model with static empirical coefficients. In this paper, a novel method utilizing daily ground in situ observations is proposed and evaluated, with the purpose for accurate estimation of long-term daily snow cover. To solve the challenge that ground snow-free records are insufficient, a one-class classifier, namely the presence and background learning (PBL) algorithm, is employed to identify daily global snow cover. Benefiting from daily ground in situ observations on a global scale, the proposed method is temporally and spatially dynamic such that estimation errors are globally independent during the entire study period. The proposed method is applied to the estimation of global daily snow cover from 1987 to 2010; the results are validated by ground in situ observations and compared with available optical-based and microwave-based snow cover products. Promising accuracy and model stability are achieved in daily, monthly and yearly validations as compared against ground observations (global omission error < 0.13, overall accuracy > 0.82 in China region, and keep stable in monthly and yearly averages). The comparison against the MODIS daily snow cover product (MOD10C1) shows good agreement under cloud-free conditions (Cohen's kappa = 0.715). The comparison against the NOAA daily Interactive Multisensor Snow and Ice Mapping System (IMS) dataset suggests promising agreement in the Northern Hemisphere. Another comparison against the AMSR-E daily SWE dataset (AE_DySno) demonstrates the efficiency of the proposed method regarding to

  8. Analytical solution for the effect of increasing CO2 on global mean temperature

    NASA Astrophysics Data System (ADS)

    Wigley, T. M. L.; Schlesinger, M. E.

    1985-06-01

    The effect on global mean temperature of forcing by a step function change in CO2 concentration and by a steady CO2 increase is analyzed. The former case involves a response time which is strongly dependent on both the effective diffusivity of the ocean below the upper mixed layer, or kappa, and the climate sensitivity, or dT(2x). In the latter case the damped response means that, at any given time, the climate system may be quite far removed from its equilibrium with the prevailing CO2 level. In earlier work this equilibrium was expressed as lag time, but this is shown to be misleading because of the sensitivity of the lag to the history of past CO2 variations. Since both the lag and the degree of disequilibrium are strongly dependent on kappa and dT(2x), and because of uncertainties in the preindustrial CO2 level, the observed global warming over the past 100 years can be shown to be compatible with a wide range of CO2-doubling temperature changes.

  9. Temperature-driven seasonal and diel variation in soil respiration in a moist subtropical forest in Puerto Rico

    NASA Astrophysics Data System (ADS)

    Gutiérrez del Arroyo, O.; Wood, T. E.; Lugo, A. E.

    2013-12-01

    Tropical forest soils are the largest natural source of carbon dioxide (CO2) to the atmosphere and have the highest soil respiration rates, globally. Currently, we have little understanding of how this large carbon (C) flux will respond to ongoing changes in climate. Identifying climatic controls and natural variability of soil respiration (Rs) in these ecosystems could improve our ability to predict feedbacks to future climate change. We measured hourly Rs in a secondary, moist subtropical forest in Puerto Rico for a 2-year period using an automated soil respiration system (LI-COR 8100) to determine at what time-scale Rs varies and whether this variability can be explained by abiotic factors such as temperature and moisture. Soil respiration varied significantly at both seasonal and diel time-scales. Mean monthly Rs ranged from 4 to 12 μmol CO2 m-2 s-1 and the seasonal variation was positively correlated with air temperature (p<0.0001, R2=0.69). In addition, Rs was notably reduced immediately following large precipitation events, possibly due to reduced diffusion rates out of the soil or low oxygen availability; however, precipitation was not related to Rs on a seasonal time-scale. Soil respiration also demonstrated significant diel variation, changing from 1.5 to 3.5 μmol CO2 m-2 s-1 throughout the day. As with seasonal variation, Rs was positively correlated to soil temperature (p<0.0001, R2=0.61) on a diel time-scale. Diel Rs was decoupled with soil temperature at midday possibly responding to a depression in photosynthesis, which may pause the transport of photosynthate to the roots. The shape of the temperature-Rs hysteresis effect changed seasonally in concert with air temperature. The significant positive effect of temperature on Rs in this forest, despite low intra-annual variability (<4°C), suggests that soil C loss from moist subtropical forests could increase as global temperatures rise. Diel hysteresis effects of Rs suggest that temperature has both

  10. Optomechanical oscillator controlled by variation in its heat bath temperature

    NASA Astrophysics Data System (ADS)

    Kolář, Michal; Ryabov, Artem; Filip, Radim

    2017-04-01

    We propose a generation of a low-noise state of optomechanical oscillator by a temperature-dependent force. We analyze the situation in which a quantum optomechanical oscillator (denoted as the membrane) is driven by an external force (produced by the piston). Both systems are embedded in a common heat bath at certain temperature T . The driving force the piston exerts on the membrane is bath temperature dependent. Initially, for T =T0 , the piston is linearly coupled to the membrane. The bath temperature is then reversibly changed to T ≠T0 . The change of temperature shifts the membrane, but simultaneously also increases its fluctuations. The resulting equilibrium state of the membrane is analyzed from the point of view of mechanical, as well as of thermodynamic, characteristics. We compare these characteristics of membrane and derive their intimate connection. Next, we cool down the thermal noise of the membrane, bringing it out of equilibrium, still being in the contact with heat bath. This cooling retains the effective canonical Gibbs state with the effective temperature T. In such case we study the analogs of the equilibrium quantities for low-noise mechanical states of the membrane.

  11. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, David; Darveniza, Mat; Orville, Richard E.; Williams, Earle R.; Goodman, Steven J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approximately equals 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approximately equals 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels. The comparisons were made for the northern winter (Nov.-Feb.), the equinox (Mar., Apr., Sept., Oct.), the northern summer (May-Aug.), and the whole year.

  12. Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging Rate

    NASA Technical Reports Server (NTRS)

    Mackerras, David; Darveniza, Mat; Orville, Richard E.; Williams, Earle R.; Goodman, Steven J.

    1999-01-01

    A global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approximately equals 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approximately equals 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels. The comparisons were made for the northern winter (Nov.-Feb.), the equinox (Mar., Apr., Sept., Oct.), the northern summer (May-Aug.), and the whole year.

  13. Impact of Surface Air Temperature and Snow Cover Depth on the Upper Soil Temperature Variations in Russia

    NASA Astrophysics Data System (ADS)

    Sherstyukov, A. B.; Sherstyukov, B. G.; Groisman, P. Y.

    2007-12-01

    A study of the impact of climate changes during for the last four decades on soil temperatures at depths up to 3.2 meters has been conducted for the territory of Russia. For the 1965-2004 period, we compiled and analyzed data from all Russian meteorological stations with long-term soil temperature observations at depths 80, 160 and 320 cm. Traditionally, these stations also observe a complete set of standard meteorological variables (that include surface air temperature and extensive monitoring of snow cover characteristics). This allowed us to investigate the impact of surface air temperatures and snow depth variations on soil temperatures in the upper soil layer, to quantify it using statistical analyses of multi-dimensional 40-year-long time series at 164 locations throughout the country, and assess the representativeness of the obtained results. Three-dimensional spatial distributions of regression and correlation coefficients were mapped for warm and cold seasons separately as well as for the entire year, and thereafter analyzed. In the permafrost zone we found special features in these fields that distinctively separate the permafrost zone from the remaining territory. In this zone, soil temperatures are practically uncorrelated with surface air temperatures and variations of the snow depth controls soil temperature variations (with R2 up to 0.5) Quantitative estimates of the contribution of mid-annual air temperature and snow cover depth in the long-term changes of mid-annual soil temperatures across the Russia territory were received. We found that the prevailing influence on soil temperature variations in the European part was surface air temperatures and in the Asian part of Russia was snow cover depth. Furthermore, increase of the winter snow depth in the permafrost zone (by preserving the heat accumulated in the warm season) promotes annual soil temperature increase and therefore may foster the further permafrost degradation associated with ongoing

  14. Regional and circadian variations of sweating rate and body surface temperature in camels (Camelus dromedarius).

    PubMed

    Abdoun, Khalid A; Samara, Emad M; Okab, Aly B; Al-Haidary, Ahmed A

    2012-07-01

    It was the aim of this study to investigate the regional variations in surface temperature and sweating rate and to visualize body thermal windows responsible for the dissipation of excess body heat in dromedary camels. This study was conducted on five dromedary camels with mean body weight of 450 ± 20.5 kg and 2 years of age. Sweating rate, skin and body surface temperature showed significant (P < 0.001) circadian variation together with the variation in ambient temperature. However, daily mean values of sweating rate, skin and body surface temperature measured on seven regions of the camel body did not significantly differ. The variation in body surface temperature compared to the variation in skin temperature was higher in the hump compared to the axillary and flank regions, indicating the significance of camel's fur in protecting the skin from daily variation in ambient temperature. Infrared thermography revealed that flank and axillary regions had lower thermal gradients at higher ambient temperature (T(a) ) and higher thermal gradients at lower T(a) , which might indicate the working of flank and axillary regions as thermal windows dissipating heat during the night. Sweating rate showed moderate correlation to skin and body surface temperatures, which might indicate their working as potential thermal drivers of sweating in camels. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

  15. What does global mean temperature tell us about local climate?

    PubMed

    Sutton, Rowan; Suckling, Emma; Hawkins, Ed

    2015-11-13

    The subject of climate feedbacks focuses attention on global mean surface air temperature (GMST) as the key metric of climate change. But what does knowledge of past and future GMST tell us about the climate of specific regions? In the context of the ongoing UNFCCC process, this is an important question for policy-makers as well as for scientists. The answer depends on many factors, including the mechanisms causing changes, the timescale of the changes, and the variables and regions of interest. This paper provides a review and analysis of the relationship between changes in GMST and changes in local climate, first in observational records and then in a range of climate model simulations, which are used to interpret the observations. The focus is on decadal timescales, which are of particular interest in relation to recent and near-future anthropogenic climate change. It is shown that GMST primarily provides information about forced responses, but that understanding and quantifying internal variability is essential to projecting climate and climate impacts on regional-to-local scales. The relationship between local forced responses and GMST is often linear but may be nonlinear, and can be greatly complicated by competition between different forcing factors. Climate projections are limited not only by uncertainties in the signal of climate change but also by uncertainties in the characteristics of real-world internal variability. Finally, it is shown that the relationship between GMST and local climate provides a simple approach to climate change detection, and a useful guide to attribution studies. © 2015 The Authors.

  16. What does global mean temperature tell us about local climate?

    PubMed Central

    Sutton, Rowan; Suckling, Emma; Hawkins, Ed

    2015-01-01

    The subject of climate feedbacks focuses attention on global mean surface air temperature (GMST) as the key metric of climate change. But what does knowledge of past and future GMST tell us about the climate of specific regions? In the context of the ongoing UNFCCC process, this is an important question for policy-makers as well as for scientists. The answer depends on many factors, including the mechanisms causing changes, the timescale of the changes, and the variables and regions of interest. This paper provides a review and analysis of the relationship between changes in GMST and changes in local climate, first in observational records and then in a range of climate model simulations, which are used to interpret the observations. The focus is on decadal timescales, which are of particular interest in relation to recent and near-future anthropogenic climate change. It is shown that GMST primarily provides information about forced responses, but that understanding and quantifying internal variability is essential to projecting climate and climate impacts on regional-to-local scales. The relationship between local forced responses and GMST is often linear but may be nonlinear, and can be greatly complicated by competition between different forcing factors. Climate projections are limited not only by uncertainties in the signal of climate change but also by uncertainties in the characteristics of real-world internal variability. Finally, it is shown that the relationship between GMST and local climate provides a simple approach to climate change detection, and a useful guide to attribution studies. PMID:26438282

  17. The EUSTACE project: combining different components of the observing system to deliver global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Rayner, Nick

    2016-04-01

    Day-to-day variations in surface air temperature affect society in many ways and are fundamental information for many climate services; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we reflect on our experience so far within the Horizon 2020 project EUSTACE of using satellite skin temperature retrievals to help us to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types and developing new statistical models of how surface air temperature varies in a connected way from place to place. We will present plans and progress along this road in the EUSTACE project (2015-June 2018): - providing new, consistent, multi-component estimation of uncertainty in surface skin temperature retrievals from satellites; - identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; - estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; - using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

  18. Top-of-atmosphere radiative contribution to unforced decadal global temperature variability in climate models

    NASA Astrophysics Data System (ADS)

    Brown, Patrick T.; Li, Wenhong; Li, Laifang; Ming, Yi

    2014-07-01

    Much recent work has focused on unforced global mean surface air temperature (T) variability associated with the efficiency of heat transport into the deep ocean. Here the relationship between unforced variability in T and the Earth's top-of-atmosphere (TOA) energy balance is explored in preindustrial control runs of the Coupled Model Intercomparison Project Phase 5 multimodel ensemble. It is found that large decadal scale variations in T tend to be significantly enhanced by the net energy flux at the TOA. This indicates that unforced decadal variability in T is not only caused by a redistribution of heat within the climate system but can also be associated with unforced changes in the total amount of heat in the climate system. It is found that the net TOA radiation imbalances result mostly from changes in albedo associated with the Interdecadal Pacific Oscillation that temporarily counteracts the climate system's outgoing longwave (i.e., Stefan-Boltzmann) response to T change.

  19. Variation in Maltese English: The Interplay of the Local and the Global in an Emerging Postcolonial Variety

    ERIC Educational Resources Information Center

    Bonnici, Lisa Marie

    2010-01-01

    In our current era of increased globalization, constraints on language variation in postcolonial English varieties are multifaceted. Local and global language ideologies collide and multiple sources of influence converge in present-day patterns of linguistic variation in emerging English varieties. While research into the structure and…

  20. Indo-Pacific warm pool area expansion, Modoki activity, and tropical cold-point tropopause temperature variations.

    PubMed

    Xie, Fei; Li, Jianping; Tian, Wenshou; Li, Yanjie; Feng, Juan

    2014-04-01

    The tropical cold-point tropopause temperature (CPTT), a potentially important indicator of global climate change, is of particular importance for understanding changes in stratospheric water vapor levels. Since the 1980s, the tropical CPTT has shown not only interannual variations, but also a decreasing trend. However, the factors controlling the variations in the tropical CPTT since the 1980s remain elusive. The present study reveals that the continuous expansion of the area of the Indo-Pacific warm pool (IPWP) since the 1980s represents an increase in the total heat energy of the IPWP available to heat the tropospheric air, which is likely to expand as a result. This process lifts the tropical cold-point tropopause height (CPTH) and leads to the observed long-term cooling trend of the tropical CPTT. In addition, our analysis shows that Modoki activity is an important factor in modulating the interannual variations of the tropical CPTT through significant effects on overshooting convection.

  1. Global mean sea level variations from TOPEX/POSEIDON altimeter data

    SciTech Connect

    Nerem, R.S.

    1995-05-05

    The TOPEX/POSEIDON satellite altimeter mission has measured global mean sea level every 10 days over the last 2 years with a precision of 4 millimeters, which approaches the requirements for climate change research. The estimated rate of sea level change is +3.9 {+-} 0.8 millimeters per year. A substantial portion of this trend may represent a short-term variation unrelated to the long-term signal expected from global warming. For this reason, and because the long-term measurement accuracy requires additional monitoring, a longer time series is necessary before climate change signals can be unequivocally detected. 37 refs., 1 fig.

  2. Global Mean Sea Level Variations from TOPEX/POSEIDON Altimeter Data.

    PubMed

    Nerem, R S

    1995-05-05

    The TOPEX/POSEIDON satellite altimeter mission has measured global mean sea level every 10 days over the last 2 years with a precision of 4 millimeters, which approaches the requirements for climate change research. The estimated rate of sea level change is +3.9 +/- 0.8 millimeters per year. A substantial portion of this trend may represent a short-term variation unrelated to the long-term signal expected from global warming. For this reason, and because the long-term measurement accuracy requires additional monitoring, a longer time series is necessary before climate change signals can be unequivocally detected.

  3. Seasonal variations of the effect of temperature on lethal and sublethal toxicities of ammonia for three common freshwater shredders.

    PubMed

    Dehedin, Arnaud; Piscart, Christophe; Marmonier, Pierre

    2013-01-01

    In a context of global change, increases in temperature and in ammonia concentration should strongly affect the crustaceans of wetlands. We experimentally examined, at three different seasons (i.e. winter, spring, and summer), the effect of temperature (12, 18, and 24°C) on the lethal (survival rates) and sublethal (oxygen consumption) toxicity of unionized ammonia (NH(3)) on the amphipods Gammarus pulex and Gammarus roeselii and the isopod Asellus aquaticus. Our results demonstrate (1) a gradient of increasing tolerance and survival from G. roeselii to G. pulex and A. aquaticus, (2) an increasing toxicity of ammonia with temperature, and (3) a strong seasonal variation of the tolerance to ammonia, with a higher tolerance of individuals in winter than in summer. However, the sub-lethal effect of ammonia on the oxygen consumption rate was species dependant and changed according to temperature or season. Global change and resulting variations in crustacean densities will potentially affect the ecosystem functioning (e.g. organic matter recycling).

  4. Temperature variation during apicectomy with Er:YAG laser.

    PubMed

    Bodrumlu, Emre; Keskiner, Ilker; Sumer, Mahmut; Sumer, A Pinar; Telcıoglu, N Tuba

    2012-08-01

    The purpose of this in vitro study was to evaluate the generated temperature of the Er:YAG laser, with three different pulse durations for apicectomy, compared with tungsten bur and surgical saw. Apicectomy is an endodontic surgery performed to remove the root apex and curette adjacent periapical tissue because of lesions of the apical area that are not healing properly. Sixty single-rooted extracted human teeth were resected by three cutting methods: tungsten bur, surgical saw, and Er:YAG laser irradiation with three different pulse durations; pulse duration 50 μs, pulse duration 100 μs, and pulse duration 300 μs. Teflon-insulated, type K thermocouples were used to measure temperature changes during the apicectomy process. Data were analyzed using the general linear models procedure of the SPSS statistical software program. Although there was no statistically significant difference for the mean values of temperature changes at 1 mm away to the cutting site of teeth, there was statistically significant difference among groups for the mean values of temperature changes at 3 mm away to the cutting site of teeth. Additionally, there was statistically significant difference among groups for the total time required for apicectomy. The laser irradiation with pulse duration 50 μs appears to have the lowest temperature rise and the shortest time required for apicectomy of the three pulse durations. However, Er:YAG laser for apicectomy in all pulse durations could be used safely for resection in endodontics in the presence of sufficient water.

  5. Buckling of Thermoviscoelastic Structures Under Temporal and Spatial Temperature Variations

    NASA Technical Reports Server (NTRS)

    Tsuyuki, Richard; Knauss, Wolfgang G.

    1992-01-01

    The problem of lateral instability of a viscoelastic in-plane loaded structure is considered in terms of thermorheolgically simple materials. As an example of a generally in-plane loaded structure, we examine the simple column under axial load: Both cyclic loading is considered (with constant or in-phase variable temperature excursions) as well as the case of constant load in the presence of thermal gradients through the thickness of the structure. The latter case involves a continuous movement of the neutral axis from the center to the colder side and then back to the center. In both cases, temperature has a very strong effect on the instability evolution, and under in-phase thermal cycling the critical loads are reduced compared to those at constant temperatures. The primary effect of thermal gradients beyond that of thermally-induced rate accelerations is occasioned by the generation of an "initial imperfection" or "structural bowing." Because the coefficient of thermal expansion tends to be large for many polymeric materials, it it may be necessary to take special care in lay-up design of composite structures intended for use under compressive loads in high-temperature applications. Finally, the implications for the temperature sensitivities of composites to micro-instability (fiber crimping) are also apparent from the results delineated here.

  6. Variational Assimilation of Global Microwave Rainfall Retrievals: Physical and Dynamical Impact on GEOS Analyses and Forecasts

    NASA Technical Reports Server (NTRS)

    Lin, Xin; Zhang, Sara Q.; Hou, Arthur Y.

    2006-01-01

    Global microwave rainfall retrievals from a 5-satellite constellation, including TMI from TRMM, SSWI from DMSP F13, F14 and F15, and AMSR-E from EOS-AQUA, are assimilated into the NASA Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) using a 1-D variational continuous assimilation (VCA) algorithm. The physical and dynamical impact of rainfall assimilation on GEOS analyses and forecasts is examined at various temporal and spatial scales. This study demonstrates that the 1-D VCA algorithm, which was originally developed and evaluated for rainfall assimilations over tropical oceans, can effectively assimilate satellite microwave rainfall retrievals and improve GEOS analyses over both the Tropics and the extratropics where the atmospheric processes are dominated by different large-scale dynamics and moist physics, and also over the land, where rainfall estimates from passive microwave radiometers are believed to be less accurate. Results show that rainfall assimilation renders the GEOS analysis physically and dynamically more consistent with the observed precipitation at the monthly-mean and 6-hour time scales. Over regions where the model precipitation tends to misbehave in distinctly different rainy regimes, the 1-D VCA algorithm, by compensating for errors in the model s moist time-tendency in a 6-h analysis window, is able to bring the rainfall analysis closer to the observed. The radiation and cloud fields also tend to be in better agreement with independent satellite observations in the rainfall-assimilation m especially over regions where rainfall analyses indicate large improvements. Assimilation experiments with and without rainfall data for a midlatitude frontal system clearly indicates that the GEOS analysis is improved through changes in the thermodynamic and dynamic fields that respond to the rainfall assimilation. The synoptic structures of temperature, moisture, winds, divergence, and vertical motion, as well as vorticity are more

  7. Measurements of Temperature Variations in the Atmosphere near the Tropopause with Reference to Airspeed Calibration by the Temperature Method

    NASA Technical Reports Server (NTRS)

    Lina, Lindsay J; Ricker, Harry H , Jr

    1952-01-01

    Measurements of temperature variations in the atmosphere near the tropopause over land in the vicinity of Langley Field, Va., are presented. This investigation was made for the purpose of obtaining information on the accuracy of the temperature method(NACA TN 2046) of airspeed calibration over the range of Mach number from 0.6 to .08. The temperature surveys and the description of a specially designed thermometer are also presented.

  8. Modelling the effect of temperature variation on the seasonal dynamics of Ixodes ricinus tick populations.

    PubMed

    Hancock, Penelope A; Brackley, Robert; Palmer, Stephen C F

    2011-04-01

    Seasonal variation in temperature is known to drive annual patterns of tick activity and can influence the dynamics of tick-borne diseases. An age-structured model of the dynamics of Ixodes ricinus populations was developed to explore how changes in average temperature and different levels of temperature variability affect seasonal patterns of tick activity and the transmission of tick-borne diseases. The model produced seasonal patterns of tick emergence that are consistent with those observed throughout Great Britain. Varying average temperature across a continuous spectrum produced a systematic pattern in the times of peak emergence of questing ticks which depends on cumulative temperature over the year. Examination of the effects of between-year stochastic temperature variation on this pattern indicated that peak emergence times are more strongly affected by temperature stochasticity at certain levels of average temperature. Finally the model was extended to give a simple representation of the dynamics of a tick-borne disease. A threshold level of annual cumulative temperature was identified at which disease persistence is sensitive to stochastic temperature variation. In conclusion, the effect of changing patterns of temperature variation on the dynamics of I. ricinus ticks and the diseases they transmit may depend on the cumulative temperature over the year and will therefore vary across different locations. The results also indicate that diapause mechanisms have an important influence on seasonal patterns of tick activity and require further study. Copyright © 2011 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  9. Global exponential stability of neural networks with globally Lipschitz continuous activations and its application to linear variational inequality problem.

    PubMed

    Liang, X B; Si, J

    2001-01-01

    This paper investigates the existence, uniqueness, and global exponential stability (GES) of the equilibrium point for a large class of neural networks with globally Lipschitz continuous activations including the widely used sigmoidal activations and the piecewise linear activations. The provided sufficient condition for GES is mild and some conditions easily examined in practice are also presented. The GES of neural networks in the case of locally Lipschitz continuous activations is also obtained under an appropriate condition. The analysis results given in the paper extend substantially the existing relevant stability results in the literature, and therefore expand significantly the application range of neural networks in solving optimization problems. As a demonstration, we apply the obtained analysis results to the design of a recurrent neural network (RNN) for solving the linear variational inequality problem (VIP) defined on any nonempty and closed box set, which includes the box constrained quadratic programming and the linear complementarity problem as the special cases. It can be inferred that the linear VIP has a unique solution for the class of Lyapunov diagonally stable matrices, and that the synthesized RNN is globally exponentially convergent to the unique solution. Some illustrative simulation examples are also given.

  10. Rheological modelling of physiological variables during temperature variations at rest

    NASA Astrophysics Data System (ADS)

    Vogelaere, P.; de Meyer, F.

    1990-06-01

    The evolution with time of cardio-respiratory variables, blood pressure and body temperature has been studied on six males, resting in semi-nude conditions during short (30 min) cold stress exposure (0°C) and during passive recovery (60 min) at 20°C. Passive cold exposure does not induce a change in HR but increases VO 2, VCO 2 Ve and core temperature T re, whereas peripheral temperature is significantly lowered. The kinetic evolution of the studied variables was investigated using a Kelvin-Voigt rheological model. The results suggest that the human body, and by extension the measured physiological variables of its functioning, does not react as a perfect viscoelastic system. Cold exposure induces a more rapid adaptation for heart rate, blood pressure and skin temperatures than that observed during the rewarming period (20°C), whereas respiratory adjustments show an opposite evolution. During the cooling period of the experiment the adaptative mechanisms, taking effect to preserve core homeothermy and to obtain a higher oxygen supply, increase the energy loss of the body.

  11. Performance of radiation hardening techniques under voltage and temperature variations

    NASA Astrophysics Data System (ADS)

    Veeravalli, Varadan Savulimedu; Steininger, Andreas

    The effectiveness of the techniques to mitigate radiation particle hits in digital CMOS circuits has been mainly studied under a given set of environmental conditions. This paper will explicitly analyze, how the performance of two selected radiation hardening techniques, namely transistor sizing and stack separation, varies with temperature and supply voltage. Our target is an inverter circuit in UMC90 bulk CMOS technology, instances of which have been hardened against charges of 300fC and 450fC using either of the two techniques under investigation. In a Spice simulation we apply particle hits to these circuits through double-exponential current pulses of the respective charge. We study the effect of these pulses in a temperature range from - 55 C to +175 C and a supply voltage of 0.65 to 1.2V (nominal 1V) at the output of a (unhardened) buffer that has been connected as a load. For the hardening by sizing we observe proper operation in the range from 1.2V to 900mV, while for lower supply we observe full swing pulses of increasing magnitude when the respective maximum charge is applied. The influence of temperature turns out to be minor. For the stack separation approach the observation is similar, however, the circuit starts glitching only at 750mV. Our study allows the following conclusions: (i) The effectiveness of the hardening approaches strongly depends on the supply voltage, and moderately on temperature. (ii) As expected, low voltage and high temperature represent the worst case for rad-hard sizing. Stack separation, on the other hand, unexpectedly shows a stronger and more complicated temperature dependence. (ii) For voltages below approx. 90% of nominal the hardening by sizing fails, when designed for nominal voltage and room temperature. The approach can be enhanced to survive this worst case by increasing the sizing factor further by more than 3 times. (iv) The stack separation only fails for voltages below approx. 75% of nominal, but there is n

  12. Lava flow dynamics driven by temperature-dependent viscosity variations

    NASA Astrophysics Data System (ADS)

    Diniega, S.; Smrekar, S. E.; Anderson, S. W.; Stofan, E. R.

    2011-12-01

    As lava viscosity can change 1-2 orders of magnitude due to small changes in temperature, several studies have predicted the formation of low-viscosity/high-temperature "fingers" (similar to a Saffman-Taylor type instability) within an initially near-uniform flow. We examine the onset and evolution of such fingers within a uniform lava sheet flow due to an influx of lava with slightly-variable temperature. We assume Hele-shaw-type geometry (depth << other dimensions), Newtonian and laminar fluid flow, a simple Nahme's exponential law relating temperature and viscosity, and radiative heat-loss through the flow's upper surface. Through the use of numerical simulation and steady-state analysis of model equations, we identify solutions that provide pahoehoe lava flows with a natural mechanism for the formation of lava channels/tubes within a sheet flow. Preliminary results indicate that flow-focusing occurs rapidly due to the thermo-viscosity relation, but zones of hotter flow commonly settle into a new steady-state and it is difficult to create perpetually-lengthening hot-fingers of lava (which seem more physically similar to developing lava tubes). This suggests that additional and/or discontinuous physical processes (such as decreasing radiative rates due to thickening of the surface crust or crystallization abruptly retarding flow within lower-temperature regions) may play important roles in the continued growth of preferred flow zones. We also derive qualitative and quantitative estimates of environmental controls on finger size, spacing, and location. This work has application to Earth and planetary volcanology studies as pahoehoe flows dominate terrestrial basaltic lavas and the eruption/emplacement mechanics that yield long lava flows on the Earth and Mars are not yet well understood.

  13. Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes

    EPA Pesticide Factsheets

    There is no EPA generated dataset in this study.This dataset is associated with the following publication:Zhu, L., D. Henze, J. Bash , G. Jeong, K. Cady-Pereira, M. Shephard, M. Luo, F. Poulot, and S. Capps. Global evaluation of ammonia bidirectional exchange and livestock diurnal variation schemes. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, GERMANY, 15: 12823-12843, (2015).

  14. The Contribution of Reservoirs to Global Land Surface Water Storage Variations

    SciTech Connect

    Zhou, Tian; Nijssen, Bart; Gao, Huilin; Lettenmaier, Dennis P.

    2016-12-21

    Man-made reservoirs play a key role in the terrestrial water system. They alter water fluxes at the land surface and impact surface water storage through water management regulations for diverse purposes such as irrigation, municipal water supply, hydropower generation, and flood control. Although most developed countries have established sophisticated observing systems for many variables in the land surface water cycle, long-term and consistent records of reservoir storage are much more limited and not always shared. Furthermore, most land surface hydrological models do not represent the effects of water management activities. Here, the contribution of reservoirs to seasonal water storage variations is investigated using a large-scale water management model to simulate the effects of reservoir management at basin and continental scales. The model was run from 1948 to 2010 at a spatial resolution of 0.258 latitude–longitude. A total of 166 of the largest reservoirs in the world with a total capacity of about 3900 km3 (nearly 60%of the globally integrated reservoir capacity) were simulated. The global reservoir storage time series reflects the massive expansion of global reservoir capacity; over 30 000 reservoirs have been constructed during the past half century, with a mean absolute interannual storage variation of 89 km3. The results indicate that the average reservoir-induced seasonal storage variation is nearly 700 km3 or about 10%of the global reservoir storage. For some river basins, such as the Yellow River, seasonal reservoir storage variations can be as large as 72%of combined snow water equivalent and soil moisture storage.

  15. Quantifying the impact of early 21st century volcanic eruptions on global-mean surface temperature

    NASA Astrophysics Data System (ADS)

    Monerie, Paul-Arthur; Moine, Marie-Pierre; Terray, Laurent; Valcke, Sophie

    2017-05-01

    Despite a continuous increase in well-mixed greenhouse gases, the global-mean surface temperature has shown a quasi-stabilization since 1998. This muted warming has been linked to the combined effects of internal climate variability and external forcing. The latter includes the impact of recent increase in the volcanic activity and of solar irradiance changes. Here we used a high-resolution coupled ocean-atmosphere climate model to assess the impact of the recent volcanic eruptions on the Earth's temperature, compared with the low volcanic activity of the early 2000s. Two sets of simulations are performed, one with realistic aerosol optical depth values, and the other with a fixed value of aerosol optical depth corresponding to a period of weak volcanic activity (1998-2002). We conclude that the observed recent increase in the volcanic activity led to a reduced warming trend (from 2003 to 2012) of 0.08 °C in ten years. The induced cooling is stronger during the last five-year period (2008-2012), with an annual global mean cooling of 0.04 °C (+/- 0.04 °C). The cooling is similar in summer (0.05 °C +/- 0.04 °C cooling) than in winter (0.03 °C +/- 0.04 °C cooling), but stronger in the Northern Hemisphere than in the Southern Hemisphere. Although equatorial and Arctic precipitation decreases in summer, the change in precipitation does not indicate robust changes at a local scale. Global heat content variations are found not to be impacted by the recent increase in volcanic activity.

  16. Similar negative impacts of temperature on global wheat yield estimated by three independent methods

    USDA-ARS?s Scientific Manuscript database

    The potential impact of global temperature change on global wheat production has recently been assessed with different methods, scaling and aggregation approaches. Here we show that grid-based simulations, point-based simulations, and statistical regressions produce similar estimates of temperature ...

  17. The role of climatic forcings in variations of Portuguese temperature: A comparison of spectral and statistical methods

    NASA Astrophysics Data System (ADS)

    Morozova, Anna L.; Barlyaeva, Tatiana V.

    2016-11-01

    Monthly series of temperature parameters measured by three Portuguese meteorological stations from 1888 to 2001 were used to study the effect of different climatic forcings. Three types of external forcings were considered: anthropogenic greenhouse gases and aerosols, volcanic aerosols, and solar and geomagnetic activity variations. Long-term variations of the temperature and other parameters with characteristic periods of decades were studied by various methods including the seasonal-trend decomposition based on LOESS (LOcally wEighted regreSSion), correlation and multiple regression analyses, and wavelet/wavelet coherence analyses. Obtained results confirm the statistical dependence of the temperature variations on the volcanic and the anthropogenic influence as well as variability that can be associated with the solar activity impact. In particular, surprisingly strong bi-decadal cycles were observed in temperature series whereas the observed decadal cycles are weaker and transient. Another interesting finding is the apparent non-stationarity of the relations between the solar and atmospheric parameters probably related to periods of strong/weak global circulation or frequent/occasional volcanic eruptions or interaction between the external forcing and internal atmospheric variability.

  18. Variation in heat-shock proteins and photosynthetic thermotolerance among natural populations of Chenopodium album L. from contrasting thermal environments: implications for plant responses to global warming.

    PubMed

    Barua, Deepak; Heckathorn, Scott A; Coleman, James S

    2008-11-01

    Production of heat-shock proteins (Hsps) is a key adaptation to acute heat stress and will be important in determining plant responses to climate change. Further, intraspecifc variation in Hsps, which will influence species-level response to global warming, has rarely been examined in naturally occurring plants. To understand intraspecific variation in plant Hsps and its relevance to global warming, we examined Hsp content and thermotolerance in five naturally occurring populations of Chenopodium album L. from contrasting thermal environments grown at low and high temperatures. As expected, Hsp accumulation varied between populations, but this was related more to habitat variability than to mean temperature. Unexpectedly, Hsp accumulation decreased with increasing variability of habitat temperatures. Hsp accumulation also decreased with increased experimental growth temperatures. Physiological thermotolerance was partitioned into basal and induced components. As with Hsps, induced thermotolerance decreased with increasing temperature variability. Thus, populations native to the more stressful habitats, or grown at higher temperatures, had lower Hsp levels and induced thermotolerance, suggesting a greater reliance on basal mechanisms for thermotolerance. These results suggest that future global climate change will differentially impact ecotypes within species, possibly by selecting for increased basal versus inducible thermotolerance.

  19. Solar ultraviolet B exposure and global variation in tuberculosis incidence: an ecological analysis.

    PubMed

    Boere, Tjarda M; Visser, Douwe H; van Furth, A Marceline; Lips, Paul; Cobelens, Frank G J

    2017-06-01

    Epidemiological evidence supports vitamin D deficiency as a risk factor for tuberculosis. Differences in solar ultraviolet B (UV-B) exposure, the major source of vitamin D, might therefore partially explain global variation in tuberculosis incidence.In a global country-based ecological study, we explored the correlation between vitamin D-proxies, such as solar UV-B exposure, and other relevant variables with tuberculosis incidence, averaged over the period 2004-2013.Across 154 countries, annual solar UV-B exposure was associated with tuberculosis incidence. Tuberculosis incidence in countries in the highest quartile of UV-B exposure was 78% (95% CI 57-88%, p<0.001) lower than that in countries in the lowest quartile, taking into account other vitamin D-proxies and covariates. Of the explained global variation in tuberculosis incidence, 6.3% could be attributed to variations in annual UV-B exposure. Exposure to UV-B had a similar, but weaker association with tuberculosis notification rates in the multilevel analysis with sub-national level data for large countries (highest versus lowest quartile 29% lower incidence; p=0.057).The potential preventive applications of vitamin D supplementation in high-risk groups for tuberculosis merits further investigation. Copyright ©ERS 2017.

  20. Global Precipitation Variations and Long-term Changes Derived from the GPCP Monthly Product

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Gu, Guojun; Huffman, George; Curtis, Scott

    2005-01-01

    Global and large regional rainfall variations and possible long-term changes are examined using the 25-year (1979-2004) monthly dataset from the Global Precipitation Climatology Project (GPCP). The emphasis is to discriminate among the variations due to ENSO, volcanic events and possible long-term changes. Although the global change of precipitation in the data set is near zero, the data set does indicate an upward trend (0.13 mm/day/25yr) and a downward trend (-0.06 mm/day/25yr) over tropical oceans and lands (25S-25N), respectively. This corresponds to a 4% increase (ocean) and 2% decrease (land) during this time period. Techniques are applied to attempt to eliminate variations due to ENSO and major volcanic eruptions. The impact of the two major volcanic eruptions over the past 25 years is estimated to be about a 5% reduction in tropical rainfall. The modified data set (with ENSO and volcano effect removed) retains the same approximate change slopes, but with reduced variance leading to significance tests with results in the 90-95% range. Inter-comparisons between the GPCP, SSWI (1988-2004), and TRMM (1998-2004) rainfall products are made to increase or decrease confidence in the changes seen in the GPCP analysis.

  1. Global land carbon sink response to temperature and precipitation varies with ENSO phase

    NASA Astrophysics Data System (ADS)

    Fang, Yuanyuan; Michalak, Anna M.; Schwalm, Christopher R.; Huntzinger, Deborah N.; Berry, Joseph A.; Ciais, Philippe; Piao, Shilong; Poulter, Benjamin; Fisher, Joshua B.; Cook, Robert B.; Hayes, Daniel; Huang, Maoyi; Ito, Akihiko; Jain, Atul; Lei, Huimin; Lu, Chaoqun; Mao, Jiafu; Parazoo, Nicholas C.; Peng, Shushi; Ricciuto, Daniel M.; Shi, Xiaoying; Tao, Bo; Tian, Hanqin; Wang, Weile; Wei, Yaxing; Yang, Jia

    2017-06-01

    Climate variability associated with the El Niño-Southern Oscillation (ENSO) and its consequent impacts on land carbon sink interannual variability have been used as a basis for investigating carbon cycle responses to climate variability more broadly, and to inform the sensitivity of the tropical carbon budget to climate change. Past studies have presented opposing views about whether temperature or precipitation is the primary factor driving the response of the land carbon sink to ENSO. Here, we show that the dominant driver varies with ENSO phase. Whereas tropical temperature explains sink dynamics following El Niño conditions (r TG,P = 0.59, p < 0.01), the post La Niña sink is driven largely by tropical precipitation (r PG,T = -0.46, p = 0.04). This finding points to an ENSO-phase-dependent interplay between water availability and temperature in controlling the carbon uptake response to climate variations in tropical ecosystems. We further find that none of a suite of ten contemporary terrestrial biosphere models captures these ENSO-phase-dependent responses, highlighting a key uncertainty in modeling climate impacts on the future of the global land carbon sink.

  2. Global chemical erosion over the last 250 my: Variations due to changes in paleogeography, paleoclimate, and paleogeology

    SciTech Connect

    Gibbs, M.T.; Bluth, G.J.S.; Fawcett, P.J.; Kump, L.R.

    1999-07-01

    The authors utilize predictions of runoff from two series of GENESIS (version 1.02) climate model experiments to calculate chemical erosion rates for 12 time slices that span the Mesozoic and Cenozoic. A set of control experiments where geography is altered according to published paleogeographic reconstructions and atmospheric pCO{sub 2} is held fixed at the present-day value was designed to elucidate climate sensitivity to geography alone. A second series of experiments, where the (elevated) atmospheric CO{sub 2} level for each time slice was adapted from Berner (1991), was executed to determine the additional climate sensitivity to this parameter. By holding other climate forcing factors (for example, vegetation) constant throughout the sequence of experiments the authors evaluate the effects of systematic/coherent paleogeographic changes on runoff and temperature, and thus on global rates of chemical weathering. By using empirical relationships between runoff and bicarbonate fluxes for different rock types and maps of paleogeology they calculate global bicarbonate fluxes, taking into account spatial variations in lithology and hydrology. They find that spatial variations in lithology account for little variation in the total or silicate chemical erosion rates. Calculations suggest a weaker-than-expected CO{sub 2}-climate weathering feedback. The reasonable atmospheric pCO{sub 2} variations specified for the climate-model simulations do not lead to climatic effects that support large changes in the chemical erosion rate, compared to those generated by changing paleogeography. In general, however, they find that silicate weathering rates are similar to outgassing rates of volcanic and methamorphic CO{sub 2}.

  3. Variations of bubble cavitation and temperature elevation during acculysis

    NASA Astrophysics Data System (ADS)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2017-03-01

    High-intensity focused ultrasound (HIFU) is effective in both thermal ablations and soft-tissue fragmentation. Mechanical and thermal effects depend on the operating parameters and vary with the progress of therapy. Different types of lesions could be produced with the pulse duration of 5-30 ms, much longer than histotripsy burst but shorter than the time for tissue boiling, and pulse repetition frequency (PRF) of 0.2-5 Hz. Meanwhile, bubble cavitation and temperature elevation in the focal region were measured by passive cavitation detection (PCD) and thermocouples, respectively. Temperature in the pre-focal region is always higher than those at the focal and post-focal position in all tests. Overall, it is suggested that appropriate synergy and monitoring of mechanical and thermal effects would broaden the HIFU application and enhance its efficiency as well as safety.

  4. Periodic Interannual Variations of Midwestern United States Temperatures in December.

    DTIC Science & Technology

    1982-01-01

    ocean, atmosphere system. One of these external forces, the Chandler tide or pole wobble , has been shown to generate certain frequencies in...harmonics may be important. If so, the spectra of the response would be hard to interpret. One of the fundamental Chandler frequencies cited in the Bryson...temperature record at St. Cloud, .3868 cycles/year, if a harmonic, would be equivalent to .8066 cycles/year, very close to a fundamental Chandler

  5. The temperature variation of hydrogen diffusion coefficients in metal alloys

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    Hydrogen diffusion coefficients were measured as a function of temperature for a few metal alloys using an electrochemical evolution technique. Results from these measurements are compared to those obtained by the time-lag method. In all cases, diffusion coefficients obtained by the electrochemical method are larger than those by the time-lag method by an order of magnitude or more. These differences are attributed mainly to hydrogen trapping.

  6. Impact of Temperature on Cooling Structural Variation of Forging Dies

    NASA Astrophysics Data System (ADS)

    Piesova, Marianna; Czan, Andrej

    2014-12-01

    The article is focused on the issue of die forging in the automotive industry. The cooling effect of temperature on the structure of forged die are under review. In the article, there is elaborated the analysis of theoretical knowledge in the field, focusing on die forging and experimentally proven effect of the cooling rate on the final structure of forged dies made of hypoeutectic carbon steel C56E2.

  7. Arctic Strato-Mesospheric Temperature and Wind Variations

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Goldberg, R. A.

    2004-01-01

    Upper stratosphere and mesosphere rocket measurements are actively used to investigate interaction between the neutral, electrical, and chemical atmospheres and between lower and upper layers of these regions. Satellite temperature measurements from HALOE and from inflatable falling spheres complement each other and allow illustrations of the annual cycle to 85 km altitude. Falling sphere wind and temperature measurements reveal variability that differs as a function of altitude, location, and time. We discuss the state of the Arctic atmosphere during the summer 2002 (Andoya, Norway) and winter 2003 (ESRANGE, Sweden) campaigns of MaCWAVE. Balloon-borne profiles to 30 km altitude and sphere profiles between 50 and 90 km show unique small-scale structure. Nonetheless, there are practical implications that additional measurements are very much needed to complete the full vertical profile picture. Our discussion concentrates on the distribution of temperature and wind and their variability. However, reliable measurements from other high latitude NASA programs over a number of years are available to help properly calculate mean values and the distribution of the individual measurements. Since the available rocket data in the Arctic's upper atmosphere are sparse the results we present are basically a snapshot of atmospheric structure.

  8. Bias correction in Global Mean Temperature comparisons between Global Climate Models and implications for the deterministic and stochastic dynamics

    NASA Astrophysics Data System (ADS)

    Chapman, Sandra; Stainforth, David; Watkins, Nicholas

    2017-04-01

    Global mean temperature (GMT) provides a simple means of benchmarking a broad ensemble of global climate models (GCMs) against past observed GMT which in turn provide headline assessments of the consequences of possible future forcing scenarios. The slow variations of past changes in GMT seen in different GCMs track each other [1] and the observed GMT reasonably closely. However, the different GCMs tend to generate GMT time-series which have absolute values that are offset with respect to each other [2]. Subtracting these offsets is an integral part of comparisons between ensembles of GCMs and observed past GMT. We will discuss how this constrains how the GCMs are related to each other. The GMT of a given GCM is a macroscopic reduced variable that tracks a subset of the full information contained in the time evolving solution of that GCM. If the GMT slow timescale dynamics of different GCMs is to a good approximation the same, subject to a linear translation, then the phenomenology captured by this dynamics is essentially linear; any feedback is to leading order linear in GMT. It then follows that a linear energy balance evolution equation for GMT is sufficient to reproduce the slow timescale GMT dynamics, provided that the appropriate effective heat capacity and feedback parameters are known. As a consequence, the GCM's GMT timeseries may underestimate the impact of, and uncertainty in, the outcomes of future forcing scenarios. The offset subtraction procedure identifies a slow time-scale dynamics in model generated GMT. Fluctuations on much faster timescales do not typically track each other from one GCM to another, with the exception of major forcing events such as volcanic eruptions. This suggests that the GMT time-series can be decomposed into a slow and fast timescale which naturally leads to stochastic reduced energy balance models for GMT. [1] IPCC Chapter 9 P743 and fig 9.8,IPCC TS.1 [2] see e.g. [Mauritsen et al., Tuning the Climate of a Global Model

  9. Plastic responses in the metabolome and functional traits of maize plants to temperatu