Science.gov

Sample records for global temperature variation

  1. 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.

  2. 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.

  3. Statistical examination of climatological data relevant to global temperature variation

    SciTech Connect

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

    1992-01-01

    The research group at Southern Methodist University has been involved in the examination of climatological data as specified in the proposal. Our efforts have resulted in three papers which have been submitted to scholarly journals, as well as several other projects which should be completed either during the next six months or next year. In the following, we discuss our results to date along with projected progress within the next six months. Major topics discussed in this progress report include: testing for trend in the global temperature data; (2) defining and estimating mean global temperature change; and, (3) the effect of initial conditions on autoregressive models for global temperature data.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Statistical examination of climatological data relevant to global temperature variation. Progress report, July 1991--January 1992

    SciTech Connect

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

    1992-01-01

    The research group at Southern Methodist University has been involved in the examination of climatological data as specified in the proposal. Our efforts have resulted in three papers which have been submitted to scholarly journals, as well as several other projects which should be completed either during the next six months or next year. In the following, we discuss our results to date along with projected progress within the next six months. Major topics discussed in this progress report include: testing for trend in the global temperature data; (2) defining and estimating mean global temperature change; and, (3) the effect of initial conditions on autoregressive models for global temperature data.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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. PMID:25733877

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. 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

  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 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Variation in Regional and Global Lightning

    NASA Astrophysics Data System (ADS)

    Holzworth, R. H., II; Brundell, J. B.; McCarthy, M.; Virts, K.; Hutchins, M. L.; Jacobson, A. R.; Heckman, S.

    2015-12-01

    Daily global lightning variation over oceans and orography, caused by major weather patterns such as typhoons and seasonal weather oscillations, are determined with high time resolution. Observations of strong variations in global lightning are used to study possible variations in magnetospheric particle densities. Strong lightning patterns associated with ocean currents are demonstrated with a study of the Gulf Stream. We located all major lightning producing storms, using a clustering algorithm on 10 years of World Wide Lightning Location Network (WWLLN) data to reduce the influence of rapidly increasing lightning network detection efficiency on temporal studies. The clustered storms are used to study the variations and patterns of global and regional lightning activity. WWLLN and Earth Networks lightning detection networks have been used to show the energy per flash of lightning over the oceans is higher than over land, and the sharp contrast at the coasts will be examined.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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. PMID:26432245

  20. 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.

  1. 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

  2. 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

  3. Global color and albedo variations on Io

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1988-01-01

    The present Voyager imaging data multispectral mosaics of Io include global mosaics from each of the Voyager 1 and 2 data sets and a high-resolution mosaic of the region centered on the Ra Patera volcano. The constancy of the disk-integrated color and albedo of Io over recent decades despite volcanic activity may be due to the regular occurrence of large Pele-type plumes with relatively dark, red deposits. Io's intrinsic spectral variability involves continuous variation among three major spectral end members. Attention is given to the mapping of the data into five spectral units for the purposes of comparison with laboratory measurements of Io surface material candidates.

  4. 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.

  5. Daily temperature variations on Mars

    NASA Technical Reports Server (NTRS)

    Ditteon, R.

    1982-01-01

    It is noted that for approximately 32% of the Martian surface area no values of thermal inertia or albedo can fit the thermal observations. These temperature anomalies do not correlate with elevation, geologic units, morphology, or atmospheric dust content. All regions having a Lambert albedo less than 0.18 can be well fit with the standard thermal model, but all areas with albedo greater than 0.28 are anomalous. A strong inverse correlation is seen between the magnitude of the anomaly and the thermal inertia. This correlation is seen as indicating that some surface property is responsible for the anomaly. In the anomalous region the temperatures are observed to be warmer in the morning and cooler late in the afternoon and to decrease more slowly during the night than the Viking model temperatures. It is believed that of all the physical processes likely to occur on Mars but not included in the Viking thermal model, only a layered soil can explain the observations. A possible explanation of the layering deduced from the infrared thermal mapper observations is a layer of aeolian deposited dust about one thermal skin depth thick (1 to 4 cm), covering a duricrust.

  6. 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.

  7. 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).

  8. Predicting global variation in infectious disease severity

    PubMed Central

    Jensen, Per M.; De Fine Licht, Henrik H.

    2016-01-01

    Background and objectives: Understanding the underlying causes for the variation in case-fatality-ratios (CFR) is important for assessing the mechanism governing global disparity in the burden of infectious diseases. Variation in CFR is likely to be driven by factors such as population genetics, demography, transmission patterns and general health status. We present data here that support the hypothsis that changes in CFRs for specific diseases may be the result of serial passage through different hosts. For example passage through adults may lead to lower CFR, whereas passage through children may have the opposite effect. Accordingly changes in CFR may occur in parallel with demographic transitions. Methodology: We explored the predictability of CFR using data obtained from the World Health Organization (WHO) disease databases for four human diseases: mumps, malaria, tuberculosis and leptospirosis and assessed these for association with a range of population characteristics, such as crude birth and death rates, median age of the population, mean body mass index, proportion living in urban areas and tuberculosis vaccine coverage. We then tested this predictive model on Danish historical demographic and population data. Results: Birth rates were the best predictor for mumps and malaria CFR. For tuberculosis CFR death rates were the best predictor and for leptospirosis population density was a significant predictor. Conclusions and implications: CFR predictors differed among diseases according to their biology. We suggest that the overall result reflects an interaction between the forces driving demographic change and the virulence of human-to-human transmitted diseases. PMID:26884415

  9. Global temperature hits record again

    SciTech Connect

    Kerr, R.A.

    1991-01-01

    Climatologists cannot agree whether or not the world is experiencing a greenhouse warming. James Hansen is confidant that the warming is taking place. According to three major measures, 1990 was the hottest year on record (globe was 0.45{degrees}C warmer than normal) with Greenland being the only place below normal. Ocean surface temperatures were measured to be 0.39{degrees}C above normal, and air temperatures at altitudes of 1.5 and 9 kilometers were 0.02{degrees}C above the previous record set in 1988. Hansen claims that the surface temperature elevations measured roughly conform with projections made by his climate model.

  10. Seasonal Variation in Daily Temperature Ranges.

    NASA Astrophysics Data System (ADS)

    Ruschy, David L.; Baker, Donald G.; Skaggs, Richard H.

    1991-12-01

    Abrupt spring and autumnal changes in the daily temperature range, from low winter values to higher nonwinter values, were noted in the Minneapolis-St. Paul temperature record. Since this feature was even more evident in five rural and small town Minnesota stations, it can be accepted as real.The inverse relationship found between surface albedo and the daily temperature range indicated that the reduced winter temperature range is associated with snow cover. A second factor controlling the temperature range is cloud cover. This led to the conclusion that variation in net solar radiation is the primary factor.A strong statistical relationship between daily temperature range and the three variables considered (solar radiation, albedo, and cloud cover) was limited to the spring and fall. In March-April the statistically significant factors were solar radiation and albedo, while in October-November they were solar radiation and cloud cover. For the October-December period albedo was also statistically important.

  11. Modeling monthly mean variation of the solar global irradiation

    NASA Astrophysics Data System (ADS)

    Vindel, J. M.; Polo, J.; Zarzalejo, L. F.

    2015-01-01

    The monthly mean variation of the solar global reaching the Earth's surface has been characterized at a global level by a regression model. This model considers the monthly variation itself (to different horizons and even the maximum annual variation) as the study variable, and it is applied without using data corresponding to measured meteorological variable. Two explicative variables have been used, the variation of the extraterrestrial irradiation and the variation of the clear sky global horizontal irradiation. The work has been carried out from datasets including average global daily solar irradiation for each month of the year measured on the ground. The model quality has been proven to be very dependent of the temporal variation considered, in such a way that higher variations, that is to say, higher distances between months, lead to an improvement in the model outcomes.

  12. 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.

  13. Modeling equinox temperature variations in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Spilker, L. J.; Ferrari, C. C.; Morishima, R.

    2011-12-01

    For a few days around Saturn ring equinox, the Cassini Composite Infrared Spectrometer (CIRS) obtained data on Saturn's rings at different local times and phase angles. We examine results from 15 scans taken near equinox. The sun was shining on the south side of the rings prior to the equinox crossing. The solar elevation angle in the 15 scans varied between -0.00007 degrees and 0.036 degrees and the phase angle ranged from 30 degrees to 147 degrees. The equinox geometry is unique because the sun is edge-on to the rings. Saturn heating dominates while solar heating is at a minimum. The ring temperature varies between the lit and unlit sides of the A and B rings when the sun is the dominant heat source. With the sun shining on the rings the temperature of the lit rings decreases with increasing phase angle and the ring temperature in the shadow is less than the ring temperature at noon. At equinox the ring temperature does not decrease with increasing phase angle and the temperature at noon is no longer greater than the temperature in the shadow. As the solar elevation angle decreased the last few degrees, the ring temperatures on the lit and unlit sides rapidly decreased to the coldest temperatures observed thus far. At equinox radial and longitudinal temperature variations are observed in the A, B and C rings and the Cassini Division. The radial temperature variations result both from the decreasing Saturn solid angle with increasing distance from the planet and varying optical depth as the screening effect of optically thicker rings limits the heat contribution to primarily one hemisphere of Saturn. Both monolayer and multilayer models can explain the radial variations in ring temperature except for the A ring. A ring model fits produce temperatures that are lower than observed temperatures perhaps because of the effects from gravitational wakes, density waves and bending waves that are not included in the models. Saturn ring temperatures near equinox also vary

  14. Global patterns in lake surface temperature trends

    NASA Astrophysics Data System (ADS)

    O'Reilly, C.; Sharma, S.; Gray, D.; Hampton, S. E.; Read, J. S.; Rowley, R.; McIntyre, P. B.; Lenters, J. D.; Schneider, P.; Hook, S. J.

    2014-12-01

    Temperature profoundly affects dynamics in the water bodieson which human societies depend worldwide. Even relatively small water temperature changes can alter lake thermal structure with implications for water level, nutrient cycling, ecosystem productivity, and food web dynamics. As air temperature increases with climate change and human land use transforms watersheds, rising water temperatures have been reported for individual lakes or regions, but a global synthesis is lacking; such a synthesis is foundational for understanding the state of freshwater resources. We investigated global patterns in lake surface water temperatures between 1985 and 2009 using in-situ and satellite data from 236 lakes. We demonstrate that lakes are warming significantly around the globe, at an average rate of 0.34 °C per decade. The breadth of lakes in this study allowed examination of the diversity of drivers across global lakes, and highlighted the importance of ice cover in determining the suite of morphological and climate drivers for lake temperature dynamics. These empirical results are consistent with modeled predictions of climate change, taking into account the extent to which water warming can be modulated by local environmental conditions and thus defy simple correlations with air temperature. The water temperature changes we report have fundamental importance for thermal structure and ecosystem functioning in global water resources; recognition of the extent to which lakes are currently in transition should have broad implications for regional and global models as well as for management.

  15. Effects of temperature variation on MOSFET dosimetry.

    PubMed

    Cheung, Tsang; Butson, Martin J; Yu, Peter K N

    2004-07-01

    This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from 15 degrees C up to 40 degrees C. Thus standard irradiations performed at room temperature can be directly compared to in vivo dose assessments performed at near body temperature without a temperature correction function. The MOSFET dosimeter threshold voltage varies with temperature and this level is dependent on the dose history of the MOSFET dosimeter. However, the variation can be accounted for in the measurement method. For accurate dosimetry, the detector should be placed for approximately 60 s on a patient to allow thermal equilibrium before measurements are taken with the final reading performed whilst still attached to the patient or conversely left for approximately 120 s after removal from the patient if initial readout was measured at room temperature to allow temperature equilibrium to be established. PMID:15285264

  16. Volcanic Carbon: Global Variations in Gas Emissions

    NASA Astrophysics Data System (ADS)

    Fischer, T. P.; de Moor, M. J.

    2014-12-01

    Magmas degas volatiles during ascent from the mantle and mafic melts with 7 wt% H2O attain volatile saturation at ~15km depth. Magmatic gases are dominated by H2O, CO2 and S species, independent of their tectonic setting. At rift volcanoes, C is sourced from the mantle whereas arc volcanoes sample both mantle and subducted C. Volcanic gases provide detailed information on volatile sources and degassing processes. Comparison of fumarole gases with melt inclusions and volcanic plumes shows that most fumaroles sample degassed magma. Water, CO2 and S vary significantly between tectonic settings. The Kuriles, Japan, and Kamchatka have H2O/CO2 of 40 to 800 while other arcs such as the Cascades, Central America, S. America, Java, and Aeolian have ratios of 1 to 70. Gases from rift volcanoes have H2O/CO2 between 3 and 9. Some of these variations are due to addition of meteoric and subducted water, as evidenced by O and H isotopes. Speciation of H and C in volcanic gases are typically controlled by redox buffer reactions imposed by the Fe3+-Fe2+ (i.e. QFM) rock buffer or the SO2-H2S gas buffer. In more exotic systems such as Poás, hydrothermal S phases such as liquid native S can play a role in high T gas C and H speciation. Arcs dominate the global subaerial volcanic CO2 emission budget and arc total fluxes vary significantly i.e. only about 2 t/yr/km from the Aleutians and about 65 t/yr/km from Central America. Reasons for this are poorly constrained and may include variability in subducted material or slab/mantle conditions at depth. A large uncertainty results from use of generalized arc-wide C/S ratios, used in calculating C fluxes, and the paucity of data for remote arcs. Resolving C fluxes from subducted versus mantle or crustal (assimilated) C relies on C isotope ratios, which can vary spatially and temporally as a function of source or degassing processes. Therefore, when considering the deep C cycle and Cexchange between the interior and surface of the Earth

  17. 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

  18. Homogeneous global mean temperature time series

    SciTech Connect

    Peterson, T.C.; Easterling, D.R.; Vose, R.S.; Eischeid, J.K.

    1993-11-01

    A multi-agency effort has been underway to create a homogeneous global baseline data set suitable for studying climate change. The joint release of the Global Historical Climatology Network (GHCN, Vose et al, 1992) version I in 1992 by the National Climatic Data Center/NOAA and the Carbon Dioxide Information Analysis Center/DOE gave the climate research community the largest monthly land surface global climate data set available to date with over 6,000 temperature stations, 39% of which have more than 50 years of data and 10% have more than 100 years of data (see Figure 1). Fifteen different global or regional data sets were merged to create GHCN version 1. Ten of these source data sets have temperature data but only two have been tested and adjusted for inhomogeneities in the station time series. The majority of the station temperature time series in GHCN have not been systematically examined for discontinuities.

  19. 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.

  20. 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.

  1. 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.

  2. Global perceptions of local temperature change

    NASA Astrophysics Data System (ADS)

    Howe, Peter D.; Markowitz, Ezra M.; Lee, Tien Ming; Ko, Chia-Ying; Leiserowitz, Anthony

    2013-04-01

    It is difficult to detect global warming directly because most people experience changes only in local weather patterns, which are highly variable and may not reflect long-term global climate trends. However, local climate-change experience may play an important role in adaptation and mitigation behaviour and policy support. Previous research indicates that people can perceive and adapt to aspects of climate variability and change based on personal observations. Experience with local weather may also influence global warming beliefs. Here we examine the extent to which respondents in 89 countries detect recent changes in average local temperatures. We demonstrate that public perceptions correspond with patterns of observed temperature change from climate records: individuals who live in places with rising average temperatures are more likely than others to perceive local warming. As global climate change intensifies, changes in local temperatures and weather patterns may be increasingly detected by the global public. These findings also suggest that public opinion of climate change may shift, at least in part, in response to the personal experience of climate change.

  3. 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.

  4. Monitoring Global Monthly Mean Surface Temperatures.

    NASA Astrophysics Data System (ADS)

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

    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 distinctive patterns are seen in the correlation coefficients, which range from high (>0.8) over the extratropical continents of the Northern Hemisphere, to moderate (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.Over the oceans, sea surface temperatures (SSTS) are used in the surface dataset in place of surface air temperature and the Comprehensive Ocean-Atmosphere Data Set (COADS) has been used to show that 80% of the monthly mean air temperature variance is accounted for in regions of good data coverage. A detailed analysis of the sources of errors in in situ SSTs and an overall estimate of the noise are obtained from the COADS by assessing the variability within 2° longitude by 2° latitude boxes within each month for 1979. In regions of small spatial gradient of mean SST, individual SST measurements are representative of the monthly mean in a 2° box to within a standard error of 1.0°C in the tropics and 1.2° to 1.4°C in the extratropics. The standard error is larger

  5. Stellar luminosity variations and global warming.

    PubMed

    Foukal, P

    1994-04-01

    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. PMID:17749020

  6. Stellar luminosity variations and global warming.

    PubMed

    Foukal, P

    1994-04-01

    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.

  7. Global Monthly and Daily Precipitation Analysis for the Global Precipitation Climatology Project (GPCP): Global and Regional Variations and Trends

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George; Curtis, Scott; Bolvin, David; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The 22 year, monthly, globally complete precipitation analysis of the World Climate Research Program's (WCRP/GEWEX) Global Precipitation Climatology Project (GPCP) and the four year (1997-present) daily GPCP analysis are described in terms of the data sets and analysis techniques used in their preparation. These analyses are then used to study global and regional variations and trends during the 22 years and the shorter-time scale events that constitute those variations. The GPCP monthly data set shows no significant trend in global precipitation over the twenty years, unlike the positive trend in global surface temperatures over the past century. The global trend analysis must be interpreted carefully, however, because the inhomogeneity of the data set makes detecting a small signal very difficult, especially over this relatively short period. The relation of global (and tropical) total precipitation and ENSO (El Nino and Southern Oscillation) events is quantified with no significant signal when land and ocean are combined. In terms of regional trends 1979 to 2000 the tropics have a distribution of regional rainfall trends that has an ENSO-like pattern with features of both the El Nino and La Nina. This feature is related to a possible trend in the frequency of ENSO events (either El Nino or La Nina) over the past 20 years. Monthly anomalies of precipitation are related to ENSO variations with clear signals extending into middle and high latitudes of both hemispheres. The El Nino and La Nina mean anomalies are near mirror images of each other and when combined produce an ENSO signal with significant spatial continuity over large distances. A number of the features are shown to extend into high latitudes. Positive anomalies extend in the Southern Hemisphere from the Pacific southeastward across Chile and Argentina into the south Atlantic Ocean. In the Northern Hemisphere the counterpart feature extends across the southern U.S. and Atlantic Ocean into Europe. In the

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Symmetries of Helmholtz forms and globally variational dynamical forms

    NASA Astrophysics Data System (ADS)

    Palese, Marcella; Winterroth, Ekkehart

    2012-02-01

    Invariance properties of classes in the variational sequence suggested to Krupka et al. the idea that there should exist a close correspondence between the notions of variationality of a differential form and invariance of its exterior derivative. It was shown by them that the invariance of a closed Helmholtz form of a dynamical form is equivalent with local variationality of the Lie derivative of the dynamical form, so that the latter is locally the Euler-Lagrange form of a Lagrangian. We show that the corresponding local system of Euler-Lagrange forms is variationally equivalent to a global Euler-Lagrange form.

  15. 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.

  16. Diurnal variation of the global electric circuit from clustered thunderstorms

    NASA Astrophysics Data System (ADS)

    Hutchins, Michael L.; Holzworth, Robert H.; Brundell, James B.

    2014-01-01

    The diurnal variation of the global electric circuit is investigated using the World Wide Lightning Location Network (WWLLN), which has been shown to identify nearly all thunderstorms (using WWLLN data from 2005). To create an estimate of global electric circuit activity, a clustering algorithm is applied to the WWLLN data set to identify global thunderstorms from 2010 to 2013. Annual, seasonal, and regional thunderstorm activity is investigated in this new WWLLN thunderstorm data set in order to estimate the source behavior of the global electric circuit. Through the clustering algorithm, the total number of active thunderstorms are counted every 30 min creating a measure of the global electric circuit source function. The thunderstorm clusters are compared to precipitation radar data from the Tropical Rainfall Measurement Mission satellite and with case studies of thunderstorm evolution. The clustering algorithm reveals an average of 660±70 thunderstorms active at any given time with a peak-to-peak variation of 36%. The highest number of thunderstorms occurs in November (720±90), and the lowest number occurs in January (610±80). Thunderstorm cluster and electrified storm cloud activity are combined with thunderstorm overflight current measurements to estimate the global electric circuit thunderstorm contribution current to be 1090±70 A with a variation of 24%. By utilizing the global coverage and high time resolution of WWLLN, the total active thunderstorm count and current is shown to be less than previous estimates based on compiled climatologies.

  17. 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.

  18. Global Responses of Gravity Waves to Planetary Wave Variations during Stratospheric Sudden Warming Observed by SABER

    NASA Astrophysics Data System (ADS)

    Cullens, C. Y.; England, S.; Immel, T. J.

    2015-12-01

    This study describes the global responses of observed gravity waves (GWs) to winter planetary wave (PW) variations during stratospheric sudden warmings (SSWs) using TIMED-SABER temperature measurements. GWs affect the ionosphere and thermosphere, and it is important to understand global variations of GWs from the lower atmosphere to the thermosphere during SSWs in order to advance our understanding of vertical coupling. The responses of GWs to SSWs are shown by calculating correlations between vertical components of Eliassen-Palm (EP) fluxes in the winter polar stratosphere and global GW temperature amplitudes derived from SABER observations. Consistent with previous ground-based and satellite observations, winter EP fluxes show positive correlations with GWs in the winter hemisphere. More interestingly, winter stratospheric EP fluxes are positively correlated with GWs in the tropics and in the summer mesosphere, indicating global variations of GWs in response to PW variations in the winter hemisphere. To study the mechanism of GW response to SSWs, global wind simulations from SD-WACCM are used. Zonal wind anomalies (differences in the wind before and during SSWs) extend from the winter stratosphere to the summer mesosphere. By comparing anomalies in background winds to the observed patterns in the correlations between GWs and winter EP fluxes, we find that regions of positive correlation follow change in background winds and zero-wind lines. The results indicate that responses of SABER GWs in the summer hemisphere to winter PW variations during SSWs are likely caused by changes in GW propagation due to the changes in atmospheric circulation. These observed changes in global GWs during SSWs can affect the ionosphere and thermosphere, and studying global GW variation during SSWs is important for understanding mechanisms of vertical coupling.

  19. The seasons, global temperature, and precession

    SciTech Connect

    Thompson, D.J.

    1995-12-31

    Analysis of instrumental temperature records beginning in 1659 shows that in much of the world the dominant frequency of the seasons is one cycle per anomalistic year (the time from perihelion to perihelion, 265.25964 days), not one cycle per tropical year (the time from equinox to equinox, 265.24220 days), and that the timing of the annual temperature cycle is controlled by perihelion. The assumption that the seasons were timed by the equinoxes has caused many statistical analyses of climate data to be badly biased. Coherence between changes in the amplitude of the annual cycle and those in the average temperature show that between 1854 and 1922 there were small temperature variations, probable of solar origin. Since 1922, the phase of the Northern Hemisphere coherence between these quantities switched from 0{degrees} to 180{degrees} and implies that solar variability cannot be the sole cause of the increasing temperature over the last century. About 1940, the phase patterns of the previous 300 years began to change and now appear to be changing at an unprecendented rate. The average change in phase is not coherent with the logarithm of atmospheric CO{sub 2} concentration.

  20. The seasons, global temperature, and precession

    SciTech Connect

    Thomson, D.J.

    1995-04-07

    Analysis of instrumental temperature records beginning in 1659 shows that in much of the world the dominant frequency of the seasons is one cycle per anomalistic year (the time from perihelion to perihelion, 365.25964 days), not one cycle per tropical year (the time from equinox to equinox, 365.24220 days), and that the timing of the annual temperature cycle is controlled by perihelion. The assumption that the seasons were timed by the equinoxes has caused many statistical analyses of climate data to be badly biased. Coherence between changes in the amplitude of the annual cycle and those in the average temperature show that between 1854 and 1922 there were small temperature variations, probably of solar origin. Since 1922, the phase of the Northern Hemisphere coherence between these quantities switched from 0{degrees} to 180{degrees} and implies that solar variability cannot be the sole cause of the increasing temperature over the last century. About 1940, the phase patterns of the previous 300 years began to change and now appear to be changing at an unprecedented rate. The average change in phase is now coherent with the logarithm of atmospheric CO{sub 2} concentration. 80 refs., 13 figs.

  1. 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. PMID:25661439

  2. A global monthly sea surface temperature climatology

    SciTech Connect

    Shea, D.J.; Trenberth, K.E.; Reynolds, R.W. NOAA, Climate Analysis Center, Washington, DC )

    1992-09-01

    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. 22 refs.

  3. Effects of Spatial Variations in Coronal Temperatures on Type III Bursts. I. Variations in Electron Temperature

    NASA Astrophysics Data System (ADS)

    Li, B.; Cairns, Iver H.; Robinson, P. A.

    2011-03-01

    The electron temperature Te and ion temperature Ti in the corona vary with time and location, due to transient and persistent activity on the Sun. A method is developed for incorporating spatial variations of coronal temperatures into our previous simulation model for coronal type III bursts. The effects on type III bursts are simulated here for monotonic Te variations and/or for spatially localized disturbances in Te . Localized Te disturbances are found to have stronger effects than monotonic variations. In the presence of localized Te disturbances, the dynamic spectra of fp and 2fp emission are modulated at frequencies corresponding to the disturbances, showing intense fine structures that are narrow band and slowly drifting. The fp emission may be observable although still significantly weaker and more patchy than the 2fp emission. Distinct signatures of Te disturbances are found in the dependence on frequency of the 2fp spectral characteristics, e.g., the maximum flux. In the presence of monotonically varying Te , the frequency drift rate for 2fp emission agrees quantitatively with an extended version of the standard prediction, depending on the plasma density profile and a characteristic, non-constant beam speed, which varies with position via dependence on Te , and agrees quantitatively with the simulated beam dynamics. The results thus indicate that nonthermal type III bursts offer a new tool to probe both spatially localized Te structures and monotonic Te variations in the corona. The presence of localized Te disturbances may be responsible for some fine structures in type IIIs, e.g., the flux modulations in type IIIb bursts.

  4. 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. PMID:27206570

  5. 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.

  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. 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.

  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. 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.

  11. Ring Equinox Temperature Variations from Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Spilker, Linda J.; Ferrari, C.; Morishima, R.; Flandes, A.; Altobelli, N.; Leyrat, C.; Pilorz, S.; Edgington, S.

    2010-10-01

    Cassini's Composite infrared spectrometer (CIRS) retrieved the temperatures of Saturn's main rings at equinox as the sun traversed from the south to north side of the rings. At equinox the solar input is very small and the primary heat sources for the rings are Saturn thermal and visible energy. The main rings cooled to their lowest temperatures measured to date. The ring temperatures at equinox were: C ring, 55-75 K; B ring, 45-60 K; Cassini Division, 45 - 58 K; and A ring, 43 - 52 K. The equinox geometry is unique because Saturn heating dominates, contrasted to earlier in the mission when the primary heat source is light from the sun. Equinox temperatures are almost identical for similar geometries on the north and south sides of the main rings. Overall, the temperatures decrease with increasing distance from the planet as expected but each ring displays a slightly different behavior. For the C ring the temperature varies slightly with the Saturn local time on the particle while the temperature for the densest part of the B ring does not vary with changing geometry. Equinox results will be presented. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the CNES and CEA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  12. Temperature variations recorded during interinstitutional air shipments of laboratory mice.

    PubMed

    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 degrees C), 14.6% to low temperatures (less than 7.2 degrees C), and 61% to temperature variations of 11 degrees 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.

  13. Global Precipitation: Means, Variations and Trends During the Satellite Era (Invited)

    NASA Astrophysics Data System (ADS)

    Adler, R. F.; Gu, G.; Huffman, G. J.; Wang, J.; Ricko, M.

    2013-12-01

    Global precipitation amounts and patterns are summarized in terms of the global mean absolute value (with error bar) and inter-annual and inter-decadal variations and trends, using the Global Precipitation Climatology Project (GPCP) analyses, with comparison to TRMM, Cloudsat and other recent satellite observations. The GPCP monthly product (1979-present), a combined analysis based on various passive microwave and infrared satellite-based estimates and gauge measurements over land, is an often-used standard estimate of global precipitation. For global and regional water (and energy) balance studies the absolute magnitude of precipitation is important. Although the current GPCP analyses do not include newer data such as TRMM (passive microwave and precipitation radar), Cloudsat (cloud radar), and AMSR (passive microwave), comparison with these more modern data confirm the earlier GPCP estimates of magnitude in terms of tropical ocean and global ocean areas, where, unlike over land, we have to rely on the satellite remote sensing for absolute values. During the last 30 years inter-annual variations of global total precipitation can be detected with small increases (a few percent) occurring during El Ninos and decreases (up to ~4%) related to effects of volcanoes. Inter-annual patterns of precipitation variation are also quite evident, especially with ENSO events. During this 30-year period global surface temperature has increased due to global warming along with an increase in atmospheric water vapor, with a Clausius-Clapeyron (~7%/C) rate. However, global precipitation (according to the GPCP analyses) has increased only slightly, if at all (0-2 %/C). This weaker relation global temperature and precipitation is in agreement with theory and climate model simulations. However, there are significant patterns of positive and negative trends in precipitation across the globe during the period. However, it also is noted that a 'climate shift' has occurred at about 1998

  14. 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.

  15. 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.

  16. High Resolution Global Electrical Conductivity Variations in the Earth's Mantle

    NASA Astrophysics Data System (ADS)

    Kelbert, A.; Sun, J.; Egbert, G. D.

    2013-12-01

    Electrical conductivity of the Earth's mantle is a valuable constraint on the water content and melting processes. In Kelbert et al. (2009), we obtained the first global inverse model of electrical conductivity in the mantle capable of providing constraints on the lateral variations in mantle water content. However, in doing so we had to compromise on the problem complexity by using the historically very primitive ionospheric and magnetospheric source assumptions. In particular, possible model contamination by the auroral current systems had greatly restricted our use of available data. We have now addressed this problem by inverting for the external sources along with the electrical conductivity variations. In this study, we still focus primarily on long period data that are dominated by quasi-zonal source fields. The improved understanding of the ionospheric sources allows us to invert the magnetic fields directly, without a correction for the source and/or the use of transfer functions. It allows us to extend the period range of available data to 1.2 days - 102 days, achieving better sensitivity to the upper mantle and transition zone structures. Finally, once the source effects in the data are accounted for, a much larger subset of observatories may be used in the electrical conductivity inversion. Here, we use full magnetic fields at 207 geomagnetic observatories, which include mid-latitude, equatorial and high latitude data. Observatory hourly means from the years 1958-2010 are employed. The improved quality and spatial distribution of the data set, as well as the high resolution modeling and inversion using degree and order 40 spherical harmonics mapped to a 2x2 degree lateral grid, all contribute to the much improved resolution of our models, representing a conceptual step forward in global electromagnetic sounding. We present a fully three-dimensional, global electrical conductivity model of the Earth's mantle as inferred from ground geomagnetic

  17. 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.

  18. The Uncertainty of Long-term Linear Trend in Global SST Due to Internal Variation

    NASA Astrophysics Data System (ADS)

    Lian, Tao

    2016-04-01

    In most parts of the global ocean, the magnitude of the long-term linear trend in sea surface temperature (SST) is much smaller than the amplitude of local multi-scale internal variation. One can thus use the record of a specified period to arbitrarily determine the value and the sign of the long-term linear trend in regional SST, and further leading to controversial conclusions on how global SST responds to global warming in the recent history. Analyzing the linear trend coefficient estimated by the ordinary least-square method indicates that the linear trend consists of two parts: One related to the long-term change, and the other related to the multi-scale internal variation. The sign of the long-term change can be correctly reproduced only when the magnitude of the linear trend coefficient is greater than a theoretical threshold which scales the influence from the multi-scale internal variation. Otherwise, the sign of the linear trend coefficient will depend on the phase of the internal variation, or in the other words, the period being used. An improved least-square method is then proposed to reduce the theoretical threshold. When apply the new method to a global SST reconstruction from 1881 to 2013, we find that in a large part of Pacific, the southern Indian Ocean and North Atlantic, the influence from the multi-scale internal variation on the sign of the linear trend coefficient can-not be excluded. Therefore, the resulting warming or/and cooling linear trends in these regions can-not be fully assigned to global warming.

  19. Concomitant interindividual variation in body temperature and metabolic rate.

    PubMed

    Rising, R; Keys, A; Ravussin, E; Bogardus, C

    1992-10-01

    There is significant variation in metabolic rate in humans, independent of differences in body size, body composition, age, and gender. Although it has been generally held that the normal human "set-point" body temperature is 37 degrees C, these interindividual variations in metabolic rate also suggest possible variations in body temperature. To examine the possibility of correlations between metabolic rate and body temperature, triplicate measurements of oral temperatures were made before and after measurement of 24-h energy expenditure in a respiratory chamber in 23 Pima Indian men. Fasting oral temperatures varied more between individuals than can be attributed to methodological errors or intraindividual variation. Oral temperatures correlated with sleeping (r = 0.80, P < 0.0001), and 24-h (r = 0.48, P < 0.02) metabolic rates adjusted for differences in body size, body composition, and age. Similarly, in the 32 Caucasian men of the Minnesota Semi-Starvation Study, oral temperature correlated with adjusted metabolic rate, and the interindividual differences in body temperature were maintained throughout semistarvation and refeeding. These results suggest that a low body temperature and a low metabolic rate might be two signs of an obesity-prone syndrome in humans.

  20. 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.

  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.

  2. 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.

  3. Global climate change and phenotypic variation among red deer cohorts.

    PubMed Central

    Post, E; Stenseth, N C; Langvatn, R; Fromentin, J M

    1997-01-01

    The variability of two fitness-related phenotypic traits (body weight and a mandibular skeletal ratio) was analysed among cohorts and age-classes of red deer in Norway. Phenotypic variation among cohorts was pronounced for calves, yearlings and reproductively mature adults. Fluctuations in cohort-specific mean body weights and skeletal ratios of adults correlated with global climatic variation in winter conditions influenced by the North Atlantic Oscillation while cohorts were in utero. Red deer born following warm winters were smaller than those born after cold winters, and this inter-cohort variability persisted into adulthood. Phenotypic variation among cohorts of red deer influenced by climate change may pose consequences for fitness of cohorts since body size and condition contribute to reproductive success and survival in male and female red deer. In particular, the recent trend of increasingly warm winters in northern Europe and Scandinavia may lead to reduced body size and fecundity of red deer, and perhaps other ungulates, in those areas. PMID:9332016

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

    PubMed

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

    2014-04-01

    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.

  5. Independent Confirmation of Global Land Warming without the Use of Station Temperatures

    NASA Astrophysics Data System (ADS)

    Compo, Gilbert; Sardeshmukh, Prashant; Whitaker, Jeffrey; Brohan, Philip; Jones, Philip; McColl, Chesley

    2013-04-01

    Confidence in estimates of 20th century land warming is limited by known issues with near-surface air temperature observations from land stations. Station siting, site moves, instrument changes, changing observing practices, urban effects, land cover, land use variations, and statistical processing have all been hypothesized as affecting the trends presented by the Intergovernmental Panel on Climate Change and others. Confidence in the observed rise of global land temperatures since the 1950s is important in assessments of anthropogenic effects on climate, so any artifacts in the observed decadal and centennial variations associated with these issues could have important consequences for scientific understanding and climate policy. Here we test the station temperature observations using a completely different approach to investigate global 20th century land warming. Specifically, we ignore all land temperature observations and instead infer the temperatures from global observations of subdaily barometric pressure, monthly HadISST1.1 sea surface temperature and sea-ice concentration, and of CO2, solar and volcanic radiative forcing agents using a physically-based data assimilation system called the 20th Century Reanalysis. This independent dataset reproduces both annual variations and centennial trends found in the observational near-surface air temperature datasets, thus demonstrating the robustness of previous conclusions based on them regarding global warming.

  6. 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…

  7. A model of the diurnal variation in lake surface temperature

    NASA Astrophysics Data System (ADS)

    Hodges, Jonathan L.

    Satellite measurements of water surface temperature can benefit several environmental applications such as predictions of lake evaporation, meteorological forecasts, and predictions of lake overturning events, among others. However, limitations on the temporal resolution of satellite measurements restrict these improvements. A model of the diurnal variation in lake surface temperature could potentially increase the effective temporal resolution of satellite measurements of surface temperature, thereby enhancing the utility of these measurements in the above applications. Herein, a one-dimensional transient thermal model of a lake is used in combination with surface temperature measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites, along with ambient atmospheric conditions from local weather stations, and bulk temperature measurements to calculate the diurnal surface temperature variation for the five major lakes in the Savannah River Basin in South Carolina: Lakes Jocassee, Keowee, Hartwell, Russell, and Thurmond. The calculated solutions are used to obtain a functional form for the diurnal surface temperature variation of these lakes. Differences in diurnal variation in surface temperature between each of these lakes are identified and potential explanations for these differences are presented.

  8. DNAzyme catalytic beacon sensors that resist temperature-dependent variations.

    PubMed

    Nagraj, Nandini; Liu, Juewen; Sterling, Stephanie; Wu, Jenny; Lu, Yi

    2009-07-21

    The temperature-dependent variability of a Pb2+-specific 8-17E DNAzyme catalytic beacon sensor has been addressed through the introduction of mismatches in the DNAzyme, and the resulting sensors resist temperature-dependent variations from 4 to 30 degrees C.

  9. Seismic reflectivity effects from seasonal seafloor temperature variation

    NASA Astrophysics Data System (ADS)

    Wood, Warren T.; Martin, Kylara M.; Jung, Wooyeol; Sample, John

    2014-10-01

    The effects of seasonal temperature variation on sound speed contrasts at the seafloor are usually considered negligible in the analysis of seismic data but may be significant at large incidence angles (offsets) important for inversion of sediment elastic properties, or long-range acoustic transmission. In coastal areas, the maximum annual seafloor temperature variation can be several degrees Celsius or more, corresponding to a sound speed variation of 30 m/s or more. Thermal pulses propagate via conduction several meters into the seafloor resulting in a damped quasi-sinusoidal temperature profile with predictable wave number characteristics. The oscillating seasonal and spatial character of this signal creates a time- and frequency-dependent effect on the elastic seafloor reflectivity. Results of numerical simulations show that the expected temperature profile for most sediment types and porosities will have the strongest affect on frequencies between about 60 and 600 Hz, at incidence angles greater than about 50°.

  10. Implications of temperature variation for malaria parasite development across Africa

    PubMed Central

    Blanford, J. I.; Blanford, S.; Crane, R. G.; Mann, M. E.; Paaijmans, K. P.; Schreiber, K. V.; Thomas, M. B.

    2013-01-01

    Temperature is an important determinant of malaria transmission. Recent work has shown that mosquito and parasite biology are influenced not only by average temperature, but also by the extent of the daily temperature variation. Here we examine how parasite development within the mosquito (Extrinsic Incubation Period) is expected to vary over time and space depending on the diurnal temperature range and baseline mean temperature in Kenya and across Africa. Our results show that under cool conditions, the typical approach of using mean monthly temperatures alone to characterize the transmission environment will underestimate parasite development. In contrast, under warmer conditions, the use of mean temperatures will overestimate development. Qualitatively similar patterns hold using both outdoor and indoor temperatures. These findings have important implications for defining malaria risk. Furthermore, understanding the influence of daily temperature dynamics could provide new insights into ectotherm ecology both now and in response to future climate change. PMID:23419595

  11. Seasonal variation of photosynthetic model parameters and leaf area index from global Fluxnet eddy covariance data

    NASA Astrophysics Data System (ADS)

    Groenendijk, M.; Dolman, A. J.; Ammann, C.; Arneth, A.; Cescatti, A.; Dragoni, D.; Gash, J. H. C.; Gianelle, D.; Gioli, B.; Kiely, G.; Knohl, A.; Law, B. E.; Lund, M.; Marcolla, B.; van der Molen, M. K.; Montagnani, L.; Moors, E.; Richardson, A. D.; Roupsard, O.; Verbeeck, H.; Wohlfahrt, G.

    2011-12-01

    Global vegetation models require the photosynthetic parameters, maximum carboxylation capacity (Vcm), and quantum yield (α) to parameterize their plant functional types (PFTs). The purpose of this work is to determine how much the scaling of the parameters from leaf to ecosystem level through a seasonally varying leaf area index (LAI) explains the parameter variation within and between PFTs. Using Fluxnet data, we simulate a seasonally variable LAIF for a large range of sites, comparable to the LAIM derived from MODIS. There are discrepancies when LAIF reach zero levels and LAIM still provides a small positive value. We find that temperature is the most common constraint for LAIF in 55% of the simulations, while global radiation and vapor pressure deficit are the key constraints for 18% and 27% of the simulations, respectively, while large differences in this forcing still exist when looking at specific PFTs. Despite these differences, the annual photosynthesis simulations are comparable when using LAIF or LAIM (r2 = 0.89). We investigated further the seasonal variation of ecosystem-scale parameters derived with LAIF. Vcm has the largest seasonal variation. This holds for all vegetation types and climates. The parameter α is less variable. By including ecosystem-scale parameter seasonality we can explain a considerable part of the ecosystem-scale parameter variation between PFTs. The remaining unexplained leaf-scale PFT variation still needs further work, including elucidating the precise role of leaf and soil level nitrogen.

  12. 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.

  13. Longitude variation of ion temperature in the Io plasma torus

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Dessler, A. J.

    2004-04-01

    The Io plasma torus shows an unanticipated variation of ion temperature as a function of System III (magnetic) longitude λIII. The simple expectation for the perpendicular temperature T⊥, based on ion pick-up in a tilted dipole magnetic field, is a double-peaked function with two maxima and two minima per 360° of longitude, having an average value of ˜480 eV for S+ and a relatively small variation amplitude of ˜±7 eV. Instead, the observed T⊥(S+) near Io's orbit has only one maximum and one minimum, with a much smaller average value of ˜30 eV and a much larger relative variation amplitude of ˜±50%. To explain the observed temperature variation, we propose that the longitude variation of the Pedersen conductance of Jupiter's ionosphere causes the pickup speed of ions injected near Io to vary with longitude. We obtain a satisfactory fit to the observed temperature variation if we make the straightforward assumption that the ionospheric conductance varies inversely with the strength of the ionospheric magnetic field. Both the magnitude and phase of the observed T⊥ variation are consistent with this simple model. The observed parallel temperature T∥(S+) has a somewhat smaller average magnitude and a similar longitude variation, but shifted about 70° in phase toward larger λIII. The T∥ behavior is consistent with the idea that T∥ derives mainly from T⊥ through pitch-angle scattering in the presence of the observed corotation lag of torus plasma. The 70° phase shift requires a scattering timescale of ˜50 hours, consistent with the classical timescale for ion-ion Coulomb scattering.

  14. 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

  15. Rising temperatures reduce global wheat production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. 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

  17. 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.

  18. 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..

  19. 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.

  20. Global Stream Temperatures and Flows under Climate Change

    NASA Astrophysics Data System (ADS)

    van Vliet, M. T.; Yearsley, J. R.; Franssen, W. H.; Ludwig, F.; Haddeland, I.; Lettenmaier, D. P.; Kabat, P.

    2012-12-01

    Climate change will affect thermal and hydrologic regimes of rivers, having a direct impact on human water use and freshwater ecosystems. Here we assess the impact of climate change on stream temperature and streamflow globally. We used a physically-based stream temperature river basin model (RBM) linked to the Variable Infiltration Capacity (VIC) model. The modelling framework was adapted for global application including impacts of reservoirs and thermal heat discharges, and was validated using observed water temperature and river discharge records in large river basins globally. VIC-RBM was forced with an ensemble of bias-corrected Global Climate Model (GCM) output resulting in global projections of daily streamflow and water temperature for the 21st century. Global mean and high (95th percentile) stream temperatures are projected to increase on average by 0.8-1.6 (1.0-2.2)°C for the SRES B1-A2 scenario for 2071-2100 relative to 1971-2000. The largest water temperature increases are projected for Europe, North America, Southeast Asia, South Africa and parts of Australia. In these regions, the sensitivities for warming are exacerbated by projected decreases in summer low flows. Large increases in water temperature combined with decreases in low flows are found for the southeastern U.S., Europe and eastern China. These regions could potentially be affected by increased deterioration of water quality and freshwater habitats, and reduced water available for beneficial uses such as thermoelectric power production.

  1. 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.

  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. 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.

  4. 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

    2016-01-01

    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

  5. Global geomagnetic field mapping - from secular variation to geomagnetic excursions

    NASA Astrophysics Data System (ADS)

    Panovska, Sanja; Constable, Catherine

    2015-04-01

    declination and paleointensity variation without prior calibration. The procedure is sensitive to the starting model for the inversion and it is, therefore, important to use absolute observations to initialize the calibration factors. Global geomagnetic field evolution is investigated in terms of changes in the field morphology at the core-mantle boundary, with particular interest in following the location of reconstructed flux lobes, determining need for any longitudinal structure and hemispheric asymmetry. The Laschamp excursion behavior suggests a time-transgressive process, either a true geomagnetic field feature or a result of age inconsistencies in the underlying data. An extreme axial dipole low is associated with the Laschamp excursion, but other reported excursions during the past 100 ka do not exhibit such pronounced dipole lows. Existing field studies extending back 10 thousand years show greater geomagnetic variability in the southern hemisphere than in the north, and lower average field strength. Modeling results are used to test whether hemispheric asymmetry in secular variation and the time-averaged field persist on this time scale, whether there are detectable differences in growth versus decay rates for the axial dipole.

  6. Testing of global pressure/temperature (GPT) model and global mapping function (GMF) in GPS analyses

    NASA Astrophysics Data System (ADS)

    Kouba, J.

    2009-03-01

    Several sources of a priori meteorological data have been compared for their effects on geodetic results from GPS precise point positioning (PPP). The new global pressure and temperature model (GPT), available at the IERS Conventions web site, provides pressure values that have been used to compute a priori hydrostatic (dry) zenith path delay z h estimates. Both the GPT-derived and a simple height-dependent a priori constant z h performed well for low- and mid-latitude stations. However, due to the actual variations not accounted for by the seasonal GPT model pressure values or the a priori constant z h, GPS height solution errors can sometimes exceed 10 mm, particularly in Polar Regions or with elevation cutoff angles less than 10 degrees. Such height errors are nearly perfectly correlated with local pressure variations so that for most stations they partly (and for solutions with 5-degree elevation angle cutoff almost fully) compensate for the atmospheric loading displacements. Consequently, unlike PPP solutions utilizing a numerical weather model (NWM) or locally measured pressure data for a priori z h, the GPT-based PPP height repeatabilities are better for most stations before rather than after correcting for atmospheric loading. At 5 of the 11 studied stations, for which measured local meteorological data were available, the PPP height errors caused by a priori z h interpolated from gridded Vienna Mapping Function-1 (VMF1) data (from a NWM) were less than 0.5 mm. Height errors due to the global mapping function (GMF) are even larger than those caused by the GPT a priori pressure errors. The GMF height errors are mainly due to the hydrostatic mapping and for the solutions with 10-degree elevation cutoff they are about 50% larger than the GPT a priori errors.

  7. INTRAPULPAL TEMPERATURE VARIATION DURING BLEACHING WITH VARIOUS ACTIVATION MECHANISMS

    PubMed Central

    Michida, Sílvia Masae de Araujo; Passos, Sheila Pestana; Marimoto, Ângela Regina Kimie; Garakis, Márcia Carneiro Valera; de Araújo, Maria Amélia Máximo

    2009-01-01

    Objectives: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation. Material and Methods: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (α=0.05). Results: The mean intrapulpal temperature values (°C) in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV) values were: 1.5°C (G1), 2.9°C (G2), 1.7°C (G3) and 6.9°C (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other. Conclusions: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group. PMID:19936522

  8. 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.

  9. Time-series modeling and prediction of global monthly absolute temperature for environmental decision making

    NASA Astrophysics Data System (ADS)

    Ye, Liming; Yang, Guixia; Van Ranst, Eric; Tang, Huajun

    2013-03-01

    A generalized, structural, time series modeling framework was developed to analyze the monthly records of absolute surface temperature, one of the most important environmental parameters, using a deterministicstochastic combined (DSC) approach. Although the development of the framework was based on the characterization of the variation patterns of a global dataset, the methodology could be applied to any monthly absolute temperature record. Deterministic processes were used to characterize the variation patterns of the global trend and the cyclic oscillations of the temperature signal, involving polynomial functions and the Fourier method, respectively, while stochastic processes were employed to account for any remaining patterns in the temperature signal, involving seasonal autoregressive integrated moving average (SARIMA) models. A prediction of the monthly global surface temperature during the second decade of the 21st century using the DSC model shows that the global temperature will likely continue to rise at twice the average rate of the past 150 years. The evaluation of prediction accuracy shows that DSC models perform systematically well against selected models of other authors, suggesting that DSC models, when coupled with other ecoenvironmental models, can be used as a supplemental tool for short-term (˜10-year) environmental planning and decision making.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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. PMID:26503051

  17. 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.

  18. 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. PMID:25122193

  19. 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.

  20. 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

  1. Temperature-induced variation in yolk androgen and thyroid hormone levels in avian eggs.

    PubMed

    Ruuskanen, Suvi; Groothuis, Ton G G; Schaper, Sonja V; Darras, Veerle M; de Vries, Bonnie; Visser, Marcel E

    2016-09-01

    Global warming has substantially changed the environment, but the mechanisms to cope with these changes in animals, including the role of maternal effects, are poorly understood. Maternal effects via hormones deposited in eggs, have important environment-dependent effects on offspring development and fitness: thus females are expected to adjust these hormones to the environment, such as the ambient temperature. Longer-term temperature variation could function as a cue, predicting chick rearing conditions to which yolk hormone levels are adjusted, while short-term temperature variation during egg formation may causally affect hormone transfer to eggs. We studied the effects of ambient temperature on yolk androgens (testosterone and androstenedione) and thyroid hormones (thyroxine and triiodothyronine) in great tits (Parus major) using data from unmanipulated clutches from a wild population and from aviary birds (ad libitum food) exposed to different experimental temperature treatments during five years. Both in the wild and in captivity, longer-term pre-laying ambient temperature was not associated with clutch mean yolk hormone levels, while the way androstenedione and thyroxine levels varied across the laying sequence did associate with pre-laying temperature in the wild. Yolk testosterone levels were positively correlated with short-term temperature (during yolk formation) changes within clutches in both wild and captivity. We also report, for the first time in a wild bird, that yolk thyroxine levels correlated with a key environmental factor: thyroxine levels were negatively correlated with ambient temperature during egg formation. Thus, yolk hormone levels, especially testosterone, seem to be causally affected by ambient temperature. These short-term effects might reflect physiological changes in females with changes in ambient temperature. The adaptive value of the variation with ambient temperatures pre-laying or during egg formation should be studied with

  2. Variational principle of carbon nanotubes with temperature changes

    NASA Astrophysics Data System (ADS)

    Fan, Tao

    2010-03-01

    In this paper, the CNS are considered as the Euler-Bernoulli beams which have been used in many references about the CNS. Taken the thermal-mechanical coupling into account, the variational principle for the CNS is presented by the variational integral method. With the derivation of the varitional principle, the stationary value conditions are obtained. At last, the vibration governing equation is illustrated, which will be benefit for the numerical simulation with finite element method in further investigations. From the stationary value conditions deduced by the variational principle, it can be observed that the vibration characteristics of the CNS can be influenced by the temperature changes. It is expected to be useful for the design and application of the nano scale devices.

  3. Variational principle of carbon nanotubes with temperature changes

    NASA Astrophysics Data System (ADS)

    Fan, Tao

    2009-12-01

    In this paper, the CNS are considered as the Euler-Bernoulli beams which have been used in many references about the CNS. Taken the thermal-mechanical coupling into account, the variational principle for the CNS is presented by the variational integral method. With the derivation of the varitional principle, the stationary value conditions are obtained. At last, the vibration governing equation is illustrated, which will be benefit for the numerical simulation with finite element method in further investigations. From the stationary value conditions deduced by the variational principle, it can be observed that the vibration characteristics of the CNS can be influenced by the temperature changes. It is expected to be useful for the design and application of the nano scale devices.

  4. Effects of Spatial Variations in Coronal Electron and Ion Temperatures on Type III Bursts. II. Variations in Ion Temperature

    NASA Astrophysics Data System (ADS)

    Li, B.; Cairns, Iver H.; Robinson, P. A.

    2011-03-01

    Quasilinear-based simulations are presented for the effects on coronal type III bursts of spatially varying ion temperature Ti in the corona. The simulations use a newly developed method for integrating spatial variations of coronal temperatures into our previous simulations for constant temperatures. The effects are simulated for monotonic Ti variations and/or for spatially localized enhancements in Ti . Generally, a localized enhancement in Ti has stronger effects on type III bursts than a corresponding monotonic variation in Ti . A localized Ti enhancement causes modulations to the dynamic spectra of fp and 2fp emission at frequencies corresponding to the disturbance: a narrowband slowly drifting intensification for both fp and 2fp emission and a narrowband suppression for 2fp emission. The fp emission may become observable due to the disturbance, although still much weaker than the 2fp emission. Signatures of the Ti enhancement are found in the 2fp spectral characteristics, e.g., the maximum flux and frequency drift rate. Importantly, these signatures are distinct from those of localized disturbances in electron temperature Te . The results indicate that coronal type III bursts provide a new tool to probe and distinguish localized disturbances in Ti or Te in the corona. Additionally, the presence of multiple spatially confined Ti enhancements at different heights may produce some observed fine structures in type III bursts; e.g., stria bursts and associated flux modulations in type IIIb bursts, and flux modulations in type IIIs whose beams traverse coronal shocks.

  5. Temperature variation of Saturn's Rings with Solar Elevation

    NASA Astrophysics Data System (ADS)

    Flandes, A.; Spilker, L.; Altobelli, N.; Leyrat, C.; Pilorz, S.; Edgington, S. G.

    2008-12-01

    In its four-year orbit around Saturn, the spacecraft Cassini has achieved a large number of infrared observations of Saturn's main rings through the CIRS experiment (Cassini Composite Infrared Spectrometer). We analyze the change of temperature in the main rings (A, B and C) as function of the solar elevation with respect to the plane of the rings at very low (<6°) and high (>120°) phase angles. Specific regions of every ring were chosen in every case to rule out other effects that may produce variations in temperature as well and to account only effects due to the solar latitudinal variations. For solar elevations that cover a range from -10.1° to -23.5°, in average, the temperature variations of the A, B and C rings are around ~{8 K}, near ~{12 K} and barely ~{3 K} respectively. Simple analytical functions which depend on the solar elevation angle and the heliocentric distance are used to fit the trends observed in the data assuming either a continuous slab or idependent particle models. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the "Programme National de Planetologie". Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

  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. 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.

  8. The effect of global climate change on sea level variations along the Bulgarian Black Sea shore

    SciTech Connect

    Mungov, G.; Vesselinov, V.

    1996-12-31

    Data of long-time sea level records along the Bulgarian Black Sea shore are analyzed from the point of view of the global climate change. The analysis of the extreme levels discovers an increase of their appearance during the last 15 years. Two different periods are studied and the recent increases imply the possibility of changes in the regime of the extreme marine events in the Western Black Sea. The cycles in the mean sea levels and the statistical characteristics of the interannual (seasonal) variations are determined. Trends in the sea level records are studied for three basic periods, according the periods in the annual temperature anomalies of the northern hemisphere: 1924--1943; 1944--1973; 1974--1991. The mean sea level rise has maximum value during the first period and minimum during the last third one. This is explained with the decrease of the water inflow into the sea and some initial disturbances in its water balance due to the global climate change. The influence of the global climate change is studied using multiple regression on global environmental data.

  9. 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.

  10. 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.

  11. Nocturnal river water temperatures: Spatial and temporal variations.

    PubMed

    Wilby, R L; Johnson, M F; Toone, J A

    2014-06-01

    Nocturnal water temperature (Tw) affects the behaviour of aquatic biota and metabolism of whole rivers. However, night-time water temperature (nTw) is poorly understood because spot samples are typically taken during daylight hours, or Tw series are aggregated in ways that mask sub-daily properties. This paper examines 15-minute measurements of Tw and air temperature (Ta) collected at 36 sites in the Rivers Dove and Manifold, English Peak District. Data were stratified by day and night then analysed using hysteresis, auto-correlation and logistic regression techniques. Daily hysteresis loops show lagged responses between nTw and previous daylight air temperatures (dTa), plus the influence of groundwater and discharge variations. Logistic regression models were modified using a seasonal factor and explained between 80 and 94% of the variance in daily maximum nTw; minimum nTw were predicted with less skill, particularly for headwater sites in summer. Downstream variations in model parameters also reflect the influence of groundwater and/or riparian shade, and prevailing weather conditions. A case is presented where an intense summer storm resulted in the propagation of a thermal wave that produced maximum Tw at some sites during hours of darkness. Hence, our findings show that Tw management by riparian shade has to be seen in a catchment wide context, with anticipated benefits normalised for weather variability, extreme rainfall events, local influence of groundwater, and channel structures.

  12. 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

  13. 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

  14. Temperature variation of the structure factor of liquid helium

    NASA Astrophysics Data System (ADS)

    Isihara, A.

    1981-07-01

    The temperature variation of the structure factor S( q) of liquid helium follows S(q) = h̷2q 2{{1 + 2f(ɛ)}}/{2}mɛ , where f(ɛ) is the Bose distribution function of the quasiparticles of energy ɛ( q). For very low temperatures, the formula predicts that S( q) increases linearly with q starting from a constant, S(0) = {kT}/{mc 2}. This trend changes at temperatures higher than T I = {c h̷}/{k}√24δ 1, where δ 1 is the coefficient to q2 of the energy dispersion relation. Therefore, above around 2.78 K, a minimum of S( q) is expected. These theoretical predictions are in good agreement with the recent experimental data of Sears, Svensson, Woods and Martel based on neutron diffraction and of Hallock obtained by X-ray scattering.

  15. 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" =…

  16. 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…

  17. 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

  18. Variation in temperature during composting of food and vegetable waste.

    PubMed

    Yadav, Kunwar D; Mistry, N J; Ganvit, Bhupesh; Pandya, Daxesh

    2013-10-01

    Composting is one of the suitable method for disposal of organic waste and convert it in to organic fertilizer. For effective composting, role of temperature within the composting heap is important. Variation of temperature in the composting heap is the indicator of type of microbial biomass present during the composting. Present study was conducted to find out the minimum volume of waste for effective composting. The present study was conducted in two phases. The first phase of study was conducted to monitor the temperature variation in different volume of composting heap and second phase of study was conducted to study the leachate production in food and vegetable waste. The results of the present study revealed that minimum 80 and 100 kg of food and vegetable waste required maintaining the thermophilic and mesophilic stage. To attain the thermophilic stage the minimum volume should be around 0.5 m3 and minimum height 0.6m. Leachate was produced at initial stage of degradation and it was more in vegetable waste compared to food waste.

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

    NASA Astrophysics Data System (ADS)

    Nagy, Melinda; Petrovay, Kristóf; Erdélyi, Robert

    2016-06-01

    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.

  20. 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.

  1. 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.

  2. Saturn ring temperature variations with approaching ring equinox

    NASA Astrophysics Data System (ADS)

    Spilker, L.; Leyrat, C.; Flandes, A.; Altobelli, N.; Pilorz, S.; Ferrari, C.; Edgington, S.

    2009-04-01

    Cassini's Composite Infrared Spectrometer (CIRS) has acquired a wide-ranging set of thermal measurements of Saturn's main rings (A, B, C and Cassini Division) at solar elevations ranging from less than one degree to 24 degrees. At Saturn equinox in August the solar elevation angle will reach zero as the sun traverses from the south to north side of the rings. For the data acquired to date, temperatures were retrieved for the lit and unlit rings over a variety of ring geometries that include solar elevation, as well as spacecraft elevation, phase angle and local hour angle. To first order, the largest temperature changes on the lit face of the rings are driven by variations in phase angle while differences in temperature with changing spacecraft elevation and local time are a secondary effect. Decreasing ring temperature with decreasing solar elevation are observed for both the lit and unlit faces of the rings after phase angle and local time effects are taken into account. As the solar elevation continues to decrease, the ring temperatures are decreasing in a non-linear fashion. The difference in temperature between the lit and unlit sides of the rings is decreasing also with decreasing solar elevation. Using ring thermal models developed by Leyrat we extrapolate to the expected minimum ring temperatures at equinox for our planned CIRS ring observations. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the "Programme National de Planetologie". Copyright 2009 California Institute of Technology. Government sponsorship acknowledged.

  3. 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.

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

    PubMed

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

    2004-07-01

    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 degrees C and 1.13 degrees 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 degrees 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

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

    PubMed

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

    2004-07-01

    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 degrees C and 1.13 degrees 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 degrees 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.

  6. 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).

  7. Global signatures and seasonal variations of 630.0 nm nightglow

    NASA Astrophysics Data System (ADS)

    Chiang, J. C.; Chang, T.; Tam, S. W.; Huang, T.; Lin, C.; Chen, A. B.; Hsu, R.

    2010-12-01

    This report investigates the global midnight brightness distribution around 23:00 local time through FORMOSAT-2/ISUAL Satellite imaging observations. We focus on the OI 630.0 nm nightglow emission at ~250 km altitudes near the equator. The database used in this study includes data from 2007 to 2008. The data statistics are separated by the four seasons. The results show that the midnight brightness often occurs near the geographic equator. And the seasonal variations of the brightening locations are observed in a tendency to show up in the summer hemisphere. But the weaker nightglow brightness tends to appear from May to July. The observations presented here are also compared with modeled electron density based on the SAMI2 model. We suggest that the midnight brightness is contributed from not only pre-reversal enhancement but also from thermospheric midnight temperature maximum (MTM) effect.

  8. The global breast cancer burden: variations in epidemiology and survival.

    PubMed

    Hortobagyi, Gabriel N; de la Garza Salazar, Jaime; Pritchard, Kathleen; Amadori, Dino; Haidinger, Renate; Hudis, Clifford A; Khaled, Hussein; Liu, Mei-Ching; Martin, Miguel; Namer, Moise; O'Shaughnessy, Joyce A; Shen, Zhen Zhou; Albain, Kathy S

    2005-12-01

    Breast cancer is the most common type of cancer and the most common cause of cancer-related mortality among women worldwide. However, the burden is not evenly distributed, and, according to the best available data, there are large variations in the incidence, mortality, and survival between different countries and regions and within specific regions. Many complex factors underlie these variations, including population structure (eg, age, race, and ethnicity), lifestyle, environment, socioeconomic status, risk factor prevalence, mammography use, disease stage at diagnosis, and access to high-quality care. We review recent breast cancer incidence and mortality statistics and explore why these vary so greatly across the world. Further research is needed to fully understand the reasons for variations in breast cancer outcomes. This will aid the development of tailored strategies to improve outcomes in general as well as the standard of care for underserved populations and reduce the burden of breast cancer worldwide.

  9. 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

  10. 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.

  11. 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.

  12. Modeling Saturn Ring Temperature Variations as Solar Elevation Decreases

    NASA Astrophysics Data System (ADS)

    Spilker, L.; Flandes, A.; Altobelli, N.; Leyrat, C.; Pilorz, S.; Ferrari, C.

    2008-12-01

    After more than four years in orbit around Saturn, the Cassini Composite Infrared Spectrometer (CIRS) has acquired a wide-ranging set of thermal measurements of Saturn's main rings (A, B, C and Cassini Division). Temperatures were retrieved for the lit and unlit rings over a variety of ring geometries that include solar phase angle, spacecraft elevation, solar elevation and local hour angle. To first order, the largest temperature changes on the lit face of the rings are driven by variations in phase angle while differences in temperature with changing spacecraft elevation and local time are a secondary effect. Decreasing ring temperature with decreasing solar elevation are observed for both the lit and unlit faces of the rings after phase angle and local time effects are taken into account. For the lit rings, decreases of 2- 4 K are observed in the C ring and larger decreases, 7-10 and 10 - 13 K, are observed in the A and B rings respectively. Our thermal data cover a range of solar elevations from -21 to -8 degrees (south side of the rings). We test two simple models and evaluate how well they fit the observed decreases in temperature. The first model assumes that the particles are so widely spaced that they do not cast shadows on one another while the second model assumes that the particles are so close together they essentially form a slab. The optically thinnest and optically thickest regions of the rings show the best fits to these two end member models. We also extrapolate to the expected minimum ring temperatures at equinox. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the "Programme National de Planetologie". Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Global variation of sonic boom overpressure due to seasonal changes in atmosphere

    NASA Astrophysics Data System (ADS)

    Yamashita, Hiroshi; Obayashi, Shigeru

    2012-09-01

    Global variation of sonic boom overpressures with the realistic atmospheric gradients was discussed. The atmospheric gradients were estimated by upper-air observational radiosonde data and a simple N-wave was extrapolated through all seasonal atmospheric gradients without winds around the world. Results demonstrated that sonic boom overpressure varies widely with season and geographic position compared to that of the standard atmospheric condition. The results also showed the tendencies of the global variation in overpressure.

  19. 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

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

    PubMed

    Rohr, Jason R; Raffel, Thomas R

    2010-05-01

    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.

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

    PubMed

    Rohr, Jason R; Raffel, Thomas R

    2010-05-01

    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

  2. Preisach Model of ER Fluids Considering Temperature Variations

    NASA Astrophysics Data System (ADS)

    Han, Y. M.; Choi, S. B.; Choi, H. J.

    This paper presents a new approach for hysteresis modeling of an electro-rheological (ER) fluid. The Preisach model is adopted to describe change of an ER fluid hysteresis with temperature, and its applicability is experimentally proved by examining two significant properties under two dominant temperature conditions. As a first step, the polymethylaniline (PMA)-based ER fluid is made by dispersing the chemically synthesized PMA particles into non-conducting oil. Then, using the Couette type electroviscometer, multiple first order descending (FOD) curves are constructed to consider temperature variations in the model. Subsequently, a nonlinear hysteresis model of the ER fluid is formulated between input (electric field) and output (yield stress). A compensation strategy is also formulated in a discrete manner through the Preisach model inversion to attain desired shear stress of the ER fluid. In order to demonstrate the effectiveness of the identified hysteresis model and the tracking performance of the control strategy, the field-dependent hysteresis loop and tracking error responses are experimentally evaluated in time domain and compared with responses obtained from Bingham model.

  3. 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.

  4. 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.

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

    PubMed

    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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Predictability of global surface temperature by means of nonlinear analysis

    NASA Astrophysics Data System (ADS)

    Gimeno, L.; García, R.; Pacheco, J. M.; Hernández, E.; Ribera, P.

    2001-01-01

    The time series of annually averaged global surface temperature anomalies for the years 1856-1998 is studied through nonlinear time series analysis with the aim of estimating the predictability time. Detection of chaotic behaviour in the data indicates that there is some internal structure in the data; the data may be considered to be governed by a deterministic process and some predictability is expected. Several tests are performed on the series, with results indicating possible chaotic behaviour.

  12. 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. PMID:25009066

  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.

  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. Temperature Variations from HST Spectroscopy of NGC 1976

    NASA Astrophysics Data System (ADS)

    Rubin, R. H.; Martin, P. G.; Blagrave, K. P. M.; Dufour, R. J.; Ferland, G. J.; Liu, X.-W.; Nguyen, J. F.; Baldwin, J. A.

    2003-09-01

    We present HST/STIS long-slit spectroscopy of NGC 1976. Our goal is to measure the intrinsic line flux ratio [O III] 4364/5008 and thereby evaluate the electron temperature (T[e]) and the fractional mean-square T[e] variation (t[A]^2) across the nebula. We also measure the intrinsic line flux ratio [N II] 5756/6585 in order to estimate T[e] and t[A]^2 in the N+ region. The interpretation of the [N II] data is not as clear cut as the [O III] data because of a higher sensitivity to knowledge of the electron density (N[e]). We present results from binning the data along the various slits into tiles that are 0.5'' square. The average [O III] temperature for our four HST/STIS slits varies from 7678 K to 8358 K; t[A]^2 varies from 0.00682 to 0.0176. When we use N[e] of 8000 (for slits 1 and 2) and 3000 cm-3 (for slits 4 and 5) with Lennon & Burke (1994) collision strengths, the average [N II] temperature for each of the four slits varies from 8979 K to 9761 K; t[A]^2 varies from 0.00551 to 0.0172. The measurements of T[e] reported here are an average along each line of sight. Therefore, despite finding remarkably low t[A]^2, we cannot rule out significantly larger temperature fluctuations along the line of sight. The result that the average [N II] T[e] exceeds the average [O III] T[e] confirms what has been previously found for Orion and what is expected on theoretical grounds.

  16. 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

  17. ITRF2014 GNSS vertical velocities and global Earth figure variations

    NASA Astrophysics Data System (ADS)

    Métivier, Laurent; Rouby, Hélène; Rebischung, Paul; Altamimi, Zuheir

    2016-04-01

    We investigate the GNSS station vertical velocities provided by the new solution of the International Terrestrial Reference Frame, the ITRF2014. Constructed from a global network of approximately 1500 stations of the different space geodetic techniques, this new solution provides two times more GNSS station velocities than the ITRF2008, and shows a global pattern of vertical velocities very homogeneous regionally. As in the ITRF2008 solution, large vertical velocities can be seen over North America, Northern Europe, or Antarctica, probably induced predominantly by the Glacial Isostatic Adjustment (GIA) still occurring today since the last deglaciation. But the ITRF2014 solution shows also large vertical velocities over regions such as Greenland and Alaska clearly larger than in the ITRF2008, probably related to last decadal ice melting and its possible acceleration. We investigate different methods to calculate low degree spherical harmonics coefficient from ITRF2014 GNSS vertical velocities. We particularly focus on the components related to the geocenter motion, the ellipticity of the solid Earth, and the J2 rate, and we present time tendencies with respect to different GIA and recent ice melting models.

  18. 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

  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 variation in the diversification rate of passerine birds.

    PubMed

    Ricklefs, Robert E

    2006-10-01

    Net diversification rates were estimated for samples of primarily tribe-to-family-level clades of passerine birds, taking into account extinction as well as speciation. Two samples were used. The first consisted of 37 clades of primarily temperate North American and primarily tropical South American passerines; the second comprised a global set of 90 clades, each distributed within one or more zoogeographic regions. Circumscription and ages of clades were taken from Sibley and Ahlquist's phylogeny based on DNA hybridization, with updates from more recent sequence analysis. Under a homogeneous speciation (rate = lamda) and extinction (rate = mu) process, the expected number of species (N) after t units of time can be described by the expression, N(t)= [exp(lamda(1 - kappa) t - kappa]/(1 - kappa), where kappa = mu/lamda. A nonlinear least-squares regression for the temperate and tropical American clades with more than one species estimated kappa = 0.938 +/- 0.076 (mean +/- SE), suggesting a high rate of turnover of lineages within clades. Because of the broad confidence limits in kappa, I used values ranging from 0.80 to 0.98 to calculate speciation rates in subsequent analyses, assuming that kappa is uniform among clades and does not vary with latitude. Speciation rate among South American clades exceeded that among North American clades for all kappa, whether monophyletic lineages were included or not. The estimated speciation rate was negatively related to clade age, suggesting that proliferation within clades slows with time. In the global data set, rate of speciation decreased with clade age and increased with the area of the region or regions within which a clade is distributed, and for any given value of kappa the speciation rate was significantly higher in tropical than in temperate regions. Relaxing the assumption of latitude independence in kappa, larger clade size in the tropics could be achieved by various combinations of relative speciation and

  1. 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).

  2. 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

  3. 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.

  4. 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.

  5. Specification and prediction of global surface temperature and precipitation from global SST using CCA

    SciTech Connect

    Barnston, A.G.; Smith, T.M.

    1996-11-01

    A reconstructed sea surface temperature (SST) dataset is used to examine relationships between SST and seasonal mean surface temperature (T) and total precipitation (P) over most of the global continents for the 1950-92 period. Both specification (i.e., simultaneous) and predictive relations are studied. Canonical correlation analysis (CCA) is used to describe the relationships and to provide information aiding in physical interpretation. A sequence of four consecutive 3-month periods of global SST anomalies is related to T and P anomalies during the fourth period for the specification analyses, and to 3-month periods ranging from one to four seasons later for the predictive analyses. Dynamical specifications of the National Centers for Environmental Prediction (NCEP) atmospheric model, using observed SST anomalies as boundary conditions are also examined for confirmation of and comparison with the statistical specification relationships suggested by the CCA. 70 refs., 32 figs., 4 tabs.

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

    PubMed

    Manel, Stéphanie; Gugerli, Felix; Thuiller, Wilfried; Alvarez, Nadir; Legendre, Pierre; Holderegger, Rolf; Gielly, Ludovic; Taberlet, Pierre

    2012-08-01

    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.

  7. 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

  8. 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.

  9. 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

  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. 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.

  12. 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.

  13. 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

  14. Multidecadal variations and trends of central European temperature in simulated climates

    NASA Astrophysics Data System (ADS)

    Mikšovský, Jiří; Farda, Aleš; Belda, Michal

    2016-04-01

    Despite the steady advances in numerical modelling, the current generation of climate simulations still struggles to reliably reproduce some of the processes in the climate system and their effects. Aside from the long-term variations, related to the responses to anthropogenic and natural forcings, a great deal of attention is also being devoted to the ability of the climate models to mimic the multidecadal variability observed in the climatic records, including the possible imprints of phenomena such as Atlantic Multidecadal Oscillation or Pacific Decadal Oscillation. In this presentation, we deliver some of our findings resulting from an analysis of observed and simulated temperature variability in central Europe - a region with long history of climatic measurements, with some of the records extending back to (or even beyond) the 19th century. Comparison of the measured temperature data to multiple historical runs of the CNRM-CM5 global climate model is performed, over the 19th and 20th centuries. For the period since 1850, an analysis is also carried out for temperature series originating from various simulations within the Coupled Model Intercomparison Project Phase 5 (CMIP5). We show that while many of the studied models exhibit relatively good skill in capturing the basic statistical characteristics of regional temperature, their representation of long-term trends and multidecadal variability in the temperature series often differs substantially from the observations.

  15. Possible Ways to Improve Global Electron and Ion Temperature Models for IRI

    NASA Astrophysics Data System (ADS)

    Truhlik, V.; Triskova, L.; Smilauer, J.

    Plasma temperatures and their global distribution in the ionosphere and their dependence on the solar cycle are important parameters for knowledge of energy balance in the ionosphere-inner magnetosphere system. Since 2001 two global empirical models of the electron temperature are included in the IRI model. One of them is based on data from ISIS 1, ISIS 2, AE-C and AEROS satellites. The second was build using data from the high solar activity period (Intercosmos series satellites). Both models include local time, latitude, altitude and seasonal variations. IRI 2001 does not explicitly include any empirical model of ion temperature so far. The first version of such a model based on ACTIVE Retarding Potential Analyzer has been recently developed and was presented on IRI workshop 2003 (Triskova et al.). One of the most serious drawback of these models is absence of solar activity dependence. Another problem is in description of the altitude profiles. We have built a data base of electron and ion temperatures from all available satellite data which has been used to study relation of both temperatures, to improve their vertical profiles and to study the influence of solar activity. This data base could help to generate new series of models.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. A high-resolution global sea surface temperature climatology

    SciTech Connect

    Reynolds, R.W.; Smith, T.M.

    1995-06-01

    In response to the development of a new higher-resolution sea surface temperature (SST) analysis at the National Meteorological Center (NMC), a new monthly 1{degrees} global sea surface temperature climatology was constructed from two intermediate climatologies: the 2{degrees} SST climatology used a 30-yr 1950-1979 base period between roughly 40{degrees}S and 60{degrees}N based on in situ (ship and buoy) SST data supplemented by four years (1982-1985) of satellite SST retrievals, and sea-ice coverage data over a 12-yr period (1982-1993). The final climatology was combined from these two products so that a 1{degrees} resolution was maintained and the base period was adjusted to the 1950-1979 period wherever possible (approximately between 40{degrees}S and 60{degrees}N). Compared to the 2{degrees} climatology, the 1{degrees} climatology resolves equatorial upwelling and fronts much better. This leads to a better matching of the scales of the new analysis and climatology. In addition, because the magnitudes of large-scale features are consistently maintained in both the older 2{degrees} and the new 1{degrees} climatologies, climate monitoring of large-scale anomalies will be minimally affected by the analysis change. The use of 12 years of satellite SST retrievals makes this new climatology useful for many additional purposes because its effective resolution actually approaches 1{degrees} everywhere over the global ocean and because the mean SST values are more accurate south of 40{degrees}S than climatologies without these data. 12 refs., 16 figs.

  6. 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.

  7. A long-term association between global temperature and biodiversity, origination and extinction in the fossil record

    PubMed Central

    Mayhew, Peter J; Jenkins, Gareth B; Benton, Timothy G

    2007-01-01

    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. PMID:17956842

  8. 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.

  9. 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

  10. Variations in temperature and precipitation during Indian summer monsoon simulated by RegCM3

    NASA Astrophysics Data System (ADS)

    Dash, S. K.; Mamgain, A.; Pattnayak, K. C.; Giorgi, F.

    2012-04-01

    Variations in temperature and precipitation due to global changes have large societal impact in sectors such as agriculture and health. It is therefore very important to examine their temporal and spatial variations at the regional level in order to access the impact of climate change. In India, the most important quasi-periodic system to affect the weather and climate is the Indian summer monsoon. The local changes in the temperature and precipitation can be well examined by a regional model. RegCM3 is one such model best suited for the Indian region. This model has been integrated in the ensemble mode at 55km resolution over India for the summer monsoon season during the years 1982-2009. The model simulations are compared with observed values in detail. Comparison with observations shows that RegCM3 has slightly underestimated summer monsoon precipitation over the Central and Northeast India. Nevertheless, over these regions, RegCM3 simulated rainfall is closer to the observations when compared to other regions where rainfall is highly overestimated. The model simulated mid-tropospheric temperature shows a warm bias over the Himalayan and Tibetan regions that gives leads to the low pressure in the region. Thus the position of the monsoon trough as simulated by the model lies to the north of its original position. This is similar to the usual monsoon break condition leading to less rainfall over Central India. RegCM3 simulated surface maximum temperature shows large negative bias over the country while the surface minimum temperature is close to the observation. Nevertheless, there is a strong correlation between the all India weighted average surface temperature simulated by RegCM3 and IMD observations. At the regional level, in the Central India, both rainfall and temperature show the best correlation with the respective observed values. While examining the extreme condition in Central India, it is found that RegCM3 simulated frequencies of very wet and

  11. Numerical solution to the problem of variational assimilation of operational observational data on the ocean surface temperature

    NASA Astrophysics Data System (ADS)

    Agoshkov, V. I.; Lebedev, S. A.; Parmuzin, E. I.

    2009-02-01

    The problem of variational assimilation of satellite observational data on the ocean surface temperature is formulated and numerically investigated in order to reconstruct surface heat fluxes with the use of the global three-dimensional model of ocean hydrothermodynamics developed at the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), and observational data close to the data actually observed in specified time intervals. The algorithms of the numerical solution to the problem are elaborated and substantiated, and the data assimilation block is developed and incorporated into the global three-dimensional model. Numerical experiments are carried out with the use of the Indian Ocean water area as an example. The data on the ocean surface temperature over the year 2000 are used as observational data. Numerical experiments confirm the theoretical conclusions obtained and demonstrate the expediency of combining the model with a block of assimilating operational observational data on the surface temperature.

  12. Cultivar variation in cotton photosynthetic performance under different temperature regimes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. 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.

  14. 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.

  15. 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.

  16. Estimating 750 years of temperature variations and uncertainties in the Pyrenees by tree-ring reconstructions and climate simulations

    NASA Astrophysics Data System (ADS)

    Dorado Liñán, I.; Büntgen, U.; González-Rouco, F.; Zorita, E.; Montávez, J. P.; Gómez-Navarro, J. J.; Brunet, M.; Heinrich, I.; Helle, G.; Gutiérrez, E.

    2012-05-01

    Past temperature variations are usually inferred from proxy data or estimated using general circulation models. Comparisons between climate estimations derived from proxy records and from model simulations help to better understand mechanisms driving climate variations, and also offer the possibility to identify deficiencies in both approaches. This paper presents regional temperature reconstructions based on tree-ring maximum density series in the Pyrenees, and compares them with the output of global simulations for this region and with regional climate model simulations conducted for the target region. An ensemble of 24 reconstructions of May-to-September regional mean temperature was derived from 22 maximum density tree-ring site chronologies distributed over the larger Pyrenees area. Four different tree-ring series standardization procedures were applied, combining two detrending methods: 300-yr spline and the regional curve standardization (RCS). Additionally, different methodological variants for the regional chronology were generated by using three different aggregation methods. Calibration verification trials were performed in split periods and using two methods: regression and a simple variance matching. The resulting set of temperature reconstructions was compared with climate simulations performed with global (ECHO-G) and regional (MM5) climate models. The 24 variants of May-to-September temperature reconstructions reveal a generally coherent pattern of inter-annual to multi-centennial temperature variations in the Pyrenees region for the last 750 yr. However, some reconstructions display a marked positive trend for the entire length of the reconstruction, pointing out that the application of the RCS method to a suboptimal set of samples may lead to unreliable results. Climate model simulations agree with the tree-ring based reconstructions at multi-decadal time scales, suggesting solar variability and volcanism as the main factors controlling

  17. 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.

  18. Sub-daily resolution of earth rotation variations with Global Positioning System measurements

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.; Marcus, Steven L.; Dickey, Jean O.

    1992-01-01

    Data from a worldwide Global Positioning System (GPS) tracking experiment have been used to determine variations in earth rotation (UT1-UTC) over a time period of three weeks. Kalman filtering and smoothing enabled changes in UT1-UTC over intervals of 2 to 24 hrs to be detected with the GPS data. Internal consistency checks and comparisons with other solutions from very long baseline interferometry (VLBI) and satellite laser ranging (SLR) indicate that the GPS UT1-UTC estimates are accurate to about 2 cm. Comparison of GPS-estimated variations in UT1-UTC with 2-hr time resolution over 4 days with predicted variations computed from diurnal and semidiurnal oceanic tidal contributions strongly suggests that the observed periodic sub-daily variations of about 0.1 msec are largely of tidal origin.

  19. 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.

  20. 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. PMID:15091761

  1. 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.

  2. Seasonal composition and temperature variations monitored in Titan's stratosphere

    NASA Astrophysics Data System (ADS)

    Coustenis, Athena; Jennings, Donald E.; Nixon, Conor A.; Bampasidis, Georgios; Achterberg, Richard K.; Teanby, Nicolas; Lavvas, Panayiotis; Vinatier, Sandrine; Bjoraker, Gordon L.; Flasar, F. Michael

    2014-05-01

    Ten years after Cassini's Saturn orbit insertion, we look at the evolution of the thermal and chemical composition of Titan's atmosphere by analyzing Cassini CIRS spectra. In particular, we use CIRS data from 2004-2013 to derive the temperature structure [1,2,7] and the neutral chemistry at latitudes between 50°S and 50°N [2]. The peak in abundance in the North was observed around the northern spring equinox (NSE), with a rapid decrease after mid-2009, indicating that the vortex has shrunk. The fulfillment of one Titanian year of space and ground-based observations in 2010 provided us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment [2-7], as also reported by other studies [10, 11]. The haze and gaseous content in Titan's atmosphere has shown some significant and rapid evolution in the past couple of years as Titan has moved from Northern winter through Northern Spring Equinox (NSE, in mid-2009) to summer. The reverse is true for the Southern hemisphere. The gaseous and haze content of the atmosphere has exhibited new features marking these seasonal passes [8,9]. After inferring the haze component by adjusting the aerosol description for each latitudinal bin, we have been monitoring the molecules appearing in CIRS/FP3 looking for recent seasonal variations as the south polar region is now moving into winter. We find significant changes for all the molecules included in the 600-720 cm-1 range (C4H2, C3H4, HC3N, CO2, C6H6, and HCN), as well as R-wing lines of the HCN and C2H2 bands. Within a 2-3 yr period in the South strong factors of increase for C4H2 and C3H4 are observed, whereas 30-40% decreases are found for HCN and for CO2. A rather stable situation with its "summer" abundance is seen for C2H2 and C2H6. Most importantly, we witness the dramatic advent of HC3N and C6H6, among the most short-lived and least abundant species after late 2011 and early 2012

  3. 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.

  4. 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.

  5. Assessment of the influence of ENSO on annual global air temperatures

    NASA Astrophysics Data System (ADS)

    Privalsky, Victor E.; Jensen, Donald T.

    1995-07-01

    The connection between El Niño-Southern Oscillation (ENSO) as characterized by the Southern Oscillation Index (SOI) and the global air temperature (GAT) is studied in the time and frequency domains, within the framework of bivariate autoregressive (AR) modeling and maximum entropy spectral analysis. The linear relationship between Sol and GAT is shown to be statistically significant at the 90% confidence level for the entire frequency range from 0.0 to 0.5 cycle year -1 The GAT-SOI time series form a closed feedback loop linear system with the damping factor of 0.38 and operating frequency of 0.062 cycle year -1 The contribution of ENSO to the overall GAT variance is shown to amount to about 30%; it reaches 35% at frequencies between 0.1 and 0.2 cycle year -1 and is not less than 25% between 0.02 and 0.34 cycle year -1 At higher frequencies the contribution decreases to about 10%. A unit change in SOI leads to a 0.13°C change in the global air temperature at f ≈ 0.06 cycle year -1 whereas at the higher frequencies, the response decreases to about 0.04°C. The spectrum of ENSO-subtracted annual variations of GAT has relatively low energy in the low-frequency band and a broad maximum centered at about 0.25 cycle year -1 The spectrum of the Sol contribution to GAT variations has approximately the same shape as the GAT spectrum, which means that ENSO contributes more energy to variations of GAT at large and intermediate (4-6 years) time scales.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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

  11. 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…

  12. 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

  13. The annual variation in the global heat balance of the earth

    NASA Technical Reports Server (NTRS)

    Ellis, J. S.; Vonder Haar, T. H.; Levitus, S.; Oort, A. H.

    1978-01-01

    An annual variation with a range of 31 W/sq m is found in the global net radiation balance of the earth. The net radiation flux values measured from satellites and the changes in total heat content computed from independent sets of atmospheric and oceanic data show annual variations which are consistent with each other in both phase and magnitude. The net energy gain and loss by the planet within a year is stored and released within the system primarily by the oceans.

  14. 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.

  15. Saturn Ring Equinox Temperature Variations Retrieved by Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Spilker, L. J.; Ferrari, C. C.; Morishima, R.; Flandes, A.; Altobelli, N.; Deau, E.; Leyrat, C.; Pilorz, S.; Showalter, M.; Edgington, S. G.; Brooks, S. M.

    2010-12-01

    As the sun traversed from the south to north side of Saturn’s main rings during equinox, Cassini’s Composite infrared spectrometer (CIRS) retrieved the ring temperatures on both sides of the rings. At equinox the solar input is negligible and the primary heat sources for the rings are Saturn thermal and visible energy. As equinox approached, the main rings cooled to their lowest temperatures measured to date. The ring temperatures at equinox were: C ring, 55-75 K; B ring, 45-60 K; Cassini Division, 45 - 58 K; and A ring, 43 - 52 K. Saturn heating dominates the equinox geometry, contrasted to earlier in the mission when the primary heat source is light from the sun. Equinox temperatures are almost identical for similar geometries on the north and south sides of the main rings. Overall, the ring temperatures decrease with increasing distance from the planet as expected but each ring displays a slightly different behavior. The C ring temperatures vary slightly with the Saturn local time on the particle while the temperatures for the densest part of the B ring do not appear to vary with changing Saturn local time. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the CNES and CEA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  16. Regional Variation of Winter Temperatures in the Arctic.

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Miletta Adams, Jennifer; Bond, Nicholas A.

    1997-05-01

    The surface temperature field in the Arctic winter is primarily controlled by downward longwave radiation, which is determined by local atmospheric temperature and humidity profiles and the presence of clouds. The authors show that regional differences in the atmospheric thermal energy budget are related to the tropospheric circulation in the Arctic. Data sources include several gridded meteorological datasets and surface and rawinsonde observational data. Four independent climatologies of mean January surface temperature show consistent spatial patterns: coldest temperatures in the western Arctic north of Canada and warmer regions in the Chukchi, Greenland, and Barents Seas. Data from the five winters of 1986-90 illustrate the coupling between the surface temperature, the downward longwave radiative fields, and the tropospheric temperature and humidity fields, with monthly surface-upper-air correlations on the order of 0.6. Upper-level circulation patterns reveal features similar to the surface temperature fields, notably a persistent low center located over northern Canada; the cyclonic flow around the low is a tropospheric extension of the polar vortex. Colder and drier conditions are maintained within the vortex and communicated to the surface through radiative processes. The polar vortex also steers transient weather systems, the most important mechanism for horizontal heat transport, into the eastern Arctic, which results in as much as 25 W m2 more heat flux into the eastern Arctic than the western Arctic. A reason for the colder temperatures in the western Arctic is that the polar vortex tends to be situated downstream of the northern Rocky Mountains; this preferred location is related to orographic forcing of planetary waves. Monthly and interannual variability of winter temperatures is conditioned by the interaction of the Arctic and midlatitude circulations through the strength and position of the polar vortex.

  17. 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

  18. Local temperature variation measurement by anti-Stokes luminescence in attenuated total reflection geometry.

    PubMed

    Yamamoto, Ken; Togawa, Ryotaro; Fujimura, Ryushi; Kajikawa, Kotaro

    2016-08-22

    Strong temperature dependence of anti-Stokes luminescence intensity from Rhodamine 101 is used to probe local temperature variation at a surface region in the attenuated total reflection geometry (ATR), when heating with laser light. In this method, the measured region can be limited by observing evanescent luminescence. The near-field depth (penetration depth) was changed by the observation angle θout of the evanescent luminescence and the spatial temperature variation was observed. PMID:27557182

  19. Extracting the Global Sea Surface Temperature Evolutions of Different Timescales

    NASA Astrophysics Data System (ADS)

    Feng, J.; Wu, Z.

    2012-12-01

    A new data analysis procedure, involving empirical orthogonal functions (EOF) analysis and ensemble empirical mode decomposition (EEMD), is employed to extract the evolutions of global Sea Surface Temperature (SST) of different timescales spanning the period from 1880 to 2009 (130 yr). Specifically, EOF analysis serves as a means of lossy data compression to eliminate the spatial-temporally incoherent, noise-like part of the data; and EEMD decomposes SST time series into different time scales, which facilitates research on SST-related weather and climate phenomena that have various timescales. Through validation, it is shown that the difference between the results and the original SST time series are mostly white noises, both spatially and temporally incoherent. We apply the results to study El Niño-Southern Oscillation (ENSO) events. Each ENSO event is examined and we find an oceanic region off Baja California coast ( ) that is instrumental to some ENSO events, especially those recently called ENSO Modoki, whose initial warming may be traced back to earlier warming signals from Baja California.

  20. 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.

  1. 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

  2. Diagnostic model study of the seasonal variation of global ozone and the Antarctic ozone hole

    SciTech Connect

    Akiyoshi, H. ); Uryu, M. )

    1992-12-20

    A simple two-dimensional model is constructed to simulate and gain an understanding of the global distribution of ozone and its seasonal variation. In the model the Chapman cycle parameterized by Hartmann (1978) is used. The time dependence of the diffusion coefficients is neglected, except in the polar regions. The effects of the meridional circulation, consisting of the following three components, are taken into account: (1) an annually varying component due to the annual variation in the heating of ozone, oxygen, and water vapor, which is assumed to be anti-symmetric (symmetric with a 6 month shift) about the equator; (2) a nonseasonal, steady component of the transport circulation with ascending air in the tropics and descending air in the middle and high latitudes of both hemispheres; and (3) an annually varying component of the transport circulation which represents planetary wave activity, strong convection in the tropics, and other seasonally variable factors. Although the employed circulations and diffusion coefficients are ad hoc, the simple model simulates the main features of the global distribution of ozone and its seasonal variation. The Antarctic ozone hole is discussed from a global point of view. The possibility of a weak October minimum in the Antarctic total ozone amount, without introducing chlorine chemistry is suggested. 46 refs., 15 figs., 2 tabs.

  3. 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.

  4. Erratum to "Temperature and hydrological variations of the urban environment in the Taipei metropolitan area, Taiwan".

    PubMed

    Wang, Chung-Ho; Lin, Wen-Zer; Peng, Tsung-Ren; Tsai, Hsiao-Chung

    2009-04-15

    In this study, the temperature, precipitation and groundwater level variations and changing patterns with varied time scales are presented for Taipei metropolitan area which consists of the capital city with neighboring counties. Along with the continuous city expansion during the past decades, global warming and heat island effect have generated perceivable negative impacts on environmental and reflect on the climatic and hydrological parameters. In addition to accelerating climate warming, hydrological extremity becomes more evident during the past decades and greatly elevates the risks of drought and floods in the study area. These observations in the Taipei metropolitan area support the common hypothesis that climate variability would increase as climate warms. The air temperature records, in conjunction with hydrological data, provide useful and invaluable information for the ongoing study of subsurface environmental changes resulting from nature and anthropogenic influences in Taipei metropolitan area. The continuing climatic warming and hydrological extremity would create observable impacts on the subsurface environment of Taipei metropolitan area and need to pursue in a fast and efficient pace.

  5. Temperature and hydrological variations of the urban environment in the Taipei metropolitan area, Taiwan.

    PubMed

    Wang, Chung-Ho; Lin, Wen-Zer; Peng, Tsung-Ren; Tsai, Hsiao-Chung

    2008-10-15

    In this study, the temperature, precipitation and groundwater level variations and changing patterns with varied time scales are presented for Taipei metropolitan area which consists of the capital city with neighboring counties. Along with the continuous city expansion during the past decades, global warming and heat island effect have generated perceivable negative impacts on environmental and reflect on the climatic and hydrological parameters. In addition to accelerating climate warming, hydrological extremity becomes more evident during the past decades and greatly elevates the risks of drought and floods in the study area. These observations in the Taipei metropolitan area support the common hypothesis that climate variability would increase as climate warms. The air temperature records, in conjunction with hydrological data, provide useful and invaluable information for the ongoing study of subsurface environmental changes resulting from nature and anthropogenic influences in Taipei metropolitan area. The continuing climatic warming and hydrological extremity would create observable impacts on the subsurface environment of Taipei metropolitan area and need to pursue in a fast and efficient pace.

  6. What Fraction of Global Fire Activity Can Be Forecast Using Sea Surface Temperatures?

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Randerson, J. T.; Morton, D. C.; Andela, N.; Giglio, L.

    2015-12-01

    Variations in sea surface temperatures (SSTs) can influence climate dynamics in local and remote land areas, and thus influence fire-climate interactions that govern burned area. SST information has been recently used in statistical models to create seasonal outlooks of fire season severity in South America and as the initial condition for dynamical model predictions of fire activity in Indonesia. However, the degree to which large-scale ocean-atmosphere interactions can influence burned area in other continental regions has not been systematically explored. Here we quantified the amount of global burned area that can be predicted using SSTs in 14 different oceans regions as statistical predictors. We first examined lagged correlations between GFED4s burned area and the 14 ocean climate indices (OCIs) individually. The maximum correlations from different OCIs were used to construct a global map of fire predictability. About half of the global burned area can be forecast by this approach 3 months before the peak burning month (with a Pearson's r of 0.5 or higher), with the highest levels of predictability in Central America and Equatorial Asia. Several hotspots of predictability were identified using k-means cluster analysis. Within these regions, we tested the improvements of the forecast by using two OCIs from different oceans. Our forecast models were based on near-real-time SST data and may therefore support the development of new seasonal outlooks for fire activity that can aid the sustainable management of these fire-prone ecosystems.

  7. Forced and free variations of the surface temperature field in a general circulation model

    SciTech Connect

    North, G.R.; Yip, K.J.J.; Laiyung Leung ); Chervin, R.M. )

    1992-03-01

    The concept of forced' and free' variations of large-scale surface temperature is examined by analyzing several long runs of the Community Climate Model (CCM0) with idealized boundary conditions and forcing. (1) The planet is all land with uniform sea-level topography and fixed soil moisture. (2) The planetary surface and prescribed ozone are reflection symmetric across the equator and there is no generation of snow. (3) The obliquity is set to zero so that the climate is for a perpetual equinox solar insolation (i.e., sun fixed over the equator). After examining some relevant aspects of the undisturbed climate (surface temperature field) such as temporal and spatial autocorrelations and the corresponding spectra, two types of changes in external forcing are imposed to study the model response: (1) sinusoidal changes of the solar constant (5%, 10%, 20%, and 40% amplitudes) at periods of 15 and 30 days (the latter is the autocorrelation time for the global average surface temperature) and 20% at 60 days and (2) insertion of steady heat sources (points and zonal bands) of variable strength at the surface. Then the temporal spectra of large scales for the periodically forced climate and the ensemble-averaged influence functions are examined for the point source disturbed climates. In each class of experiments the response of ensemble-averaged amplitudes was found to be proportional to the amplitude of the forcing. These results suggest that the lowest moments of the surface temperature field have a particularly simple dependence on forcing. Furthermore, the apparent finiteness of the variance spectrum at low frequencies suggest that estimates of long-term statistics are stable in this type of atmospheric general circulation model. 31 refs., 17 figs.

  8. Geocenter location and variations in earth orientation using global positioning system measurements

    NASA Technical Reports Server (NTRS)

    Malla, R. P.; Wu, S. C.; Lichten, S. M.

    1993-01-01

    We have studied the use of GPS ground and flight tracking data to measure short-period earth orientation variations and changes in geocenter location. Comparisons between GPS-estimated earth rotation variations and those calculated from ocean tide models suggest that observed subdaily variations in earth rotation are dominated by oceanic tidal effects. Our preliminary GPS estimates for geocenter location agree with an independent satellite laser ranging estimates to 10-15 cm. Covariance analysis predicts that temporal resolution of GPS estimates for earth orientation and geocenter improves significantly when data collected from low earth-orbiting satellites as well as from ground sites are combined. The low-earth GPS tracking data enhance the accuracy and resolution for measuring high-frequency global geodynamical signals over time scales less than 1 day.

  9. Ion temperature variations in the daytime high-latitude F region

    NASA Technical Reports Server (NTRS)

    Schunk, R. W.; Sojka, J. J.

    1982-01-01

    The Schunk and Sojka (1981a, b) high latitude ionospheric model is improved through the inclusion of thermal conduction and diffusion terms in the ion energy equation, permitting the study of daytime, high latitude F layer temperature variations in a region poleward of the auroral oval. It is found that ion temperature variation with solar cycle, season and geomagnetic activity closely follows the neutral atomic oxygen variation, and that meridional electric fields of more than 40 mV/m can cause larger ion temperature changes than those due to solar cycle, seasonal or geomagnetic activity variations. In the presence of meridional electric fields, there is an upward flow of heat from the lower ionosphere that also acts to raise ion temperatures at high altitudes. Zonal electric fields affect ion temperature indirectly, through electron density changes.

  10. Use of satellite land surface temperatures in the EUSTACE global surface air temperature analysis

    NASA Astrophysics Data System (ADS)

    Ghent, D.; Good, E.; Rayner, N. A.

    2015-12-01

    EUSTACE (EU Surface Temperatures for All Corners of Earth) is a Horizon2020 project that will produce a spatially complete, near-surface air temperature (NSAT) analysis for the globe for every day since 1850. The analysis will be based on both satellite and in situ surface temperature observations over land, sea, ice and lakes, which will be combined using state-of-the-art statistical methods. The use of satellite data will enable the EUSTACE analysis to offer improved estimates of NSAT in regions that are poorly observed in situ, compared with existing in-situ based analyses. This presentation illustrates how satellite land surface temperature (LST) data - sourced from the European Space Agency (ESA) Data User Element (DUE) GlobTemperature project - will be used in EUSTACE. Satellite LSTs represent the temperature of the Earth's skin, which can differ from the corresponding NSAT by several degrees or more, particularly during the hottest part of the day. Therefore the first challenge is to develop an approach to estimate global NSAT from satellite observations. Two methods will be trialled in EUSTACE, both of which are summarised here: an established empirical regression-based approach for predicting NSAT from satellite data, and a new method whereby NSAT is calculated from LST and other parameters using a physics-based model. The second challenge is in estimating the uncertainties for the satellite NSAT estimates, which will determine how these data are used in the final blended satellite-in situ analysis. This is also important as a key component of EUSTACE is in delivering accurate uncertainty information to users. An overview of the methods to estimate the satellite NSATs is also included in this presentation.

  11. 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.

  12. Temporal-Spatial Variation of Global GPS-Derived Total Electron Content, 1999–2013

    PubMed Central

    Guo, Jinyun; Li, Wang; Liu, Xin; Kong, Qiaoli; Zhao, Chunmei; Guo, Bin

    2015-01-01

    To investigate the temporal-spatial distribution and evolutions of global Total Electron Content (TEC), we estimate the global TEC data from 1999 to 2013 by processing the GPS data collected by the International Global Navigation Satellite System (GNSS) Service (IGS) stations, and robustly constructed the TEC time series at each of the global 5°×2.5° grids. We found that the spatial distribution of the global TEC has a pattern where the number of TECs diminishes gradually from a low-latitude region to high-latitude region, and anomalies appear in the equatorial crest and Greenland. Temporal variations show that the peak TEC appears in equinoctial months, and this corresponds to the semiannual variation of TEC. Furthermore, the winter anomaly is also observed in the equatorial area of the northern hemisphere and high latitudes of the southern hemisphere. Morlet wavelet analysis is used to determine periods of TEC variations and results indicate that the 1-day, 26.5-day, semi-annual and annual cycles are the major significant periods. The fitting results of a quadratic polynomial show that the effect of solar activity on TEC is stronger in low latitudes than in mid-high latitudes, and stronger in the southern hemisphere than in the northern hemisphere. But the effect in low latitudes in the northern hemisphere is stronger than that in low latitudes in the southern hemisphere. The effect of solar activity on TECs was analyzed with the cross wavelet analysis and the wavelet coherence transformation, and we found that there appears to be a strong coherence in the period of about 27 days. So the sunspot as one index of solar activity seriously affects the TEC variations with the sun’s rotation. We fit the TEC data with the least squares spectral analysis to study the periodic variations of TEC. The changing trend of TEC is generally -0.08 TECu per year from 1999 to 2013. So TECs decrease over most areas year by year, but TECs over the Arctic around Greenland

  13. 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.

  14. 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

  15. Variations in mid tropospheric carbon dioxide, temperature and water vapour using satellite data during 2003-2011

    NASA Astrophysics Data System (ADS)

    Dhaka, Surendra

    2016-07-01

    In this presentation global, hemispherical and regional (India) variations in carbon dioxide, temperature and water vapour and their association is analysed using mid-tropospheric (300-500 hPa) Atmospheric Infra-red Sounder (AIRS) data for a period of 9 years (2003-2011). Mid-tropospheric carbon dioxide is observed to rise from ~372.61 ppm to ~392.94 ppm over the globe and 373.38 ppm to 392.48 ppm over India from 2003 to 2011. However no significant changes are observed in mid-tropospheric temperature and water vapour variations for the same period. De-trended data of temperature and water vapour shows a high correlation between them, but no significant correlation was observed between temperature and carbon dioxide over the studied regions. The absence of immediate co-relation between temperature and carbon dioxide is the evidence that rise in carbon dioxide in the atmosphere will not imply more absorption over the earth surface. This may be explained because of the absorbing effect of carbon dioxide which is very small as compared to water vapour. The role of water vapour is reinforced because unlike carbon dioxide, water vapour in the atmosphere is changing in tune with temperature.

  16. 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.

  17. 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.

  18. 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.

  19. Low-frequency variations in surface atmospheric humidity, temperature, and precipitation: Inferences from reanalyses and monthly gridded observational data sets

    NASA Astrophysics Data System (ADS)

    Simmons, A. J.; Willett, K. M.; Jones, P. D.; Thorne, P. W.; Dee, D. P.

    2010-01-01

    Evidence is presented of a reduction in relative humidity over low-latitude and midlatitude land areas over a period of about 10 years leading up to 2008, based on monthly anomalies in surface air temperature and humidity from comprehensive European Centre for Medium-Range Weather Forecasts reanalyses (ERA-40 and ERA-Interim) and from Climatic Research Unit and Hadley Centre analyses of monthly station temperature data (CRUTEM3) and synoptic humidity observations (HadCRUH). The data sets agree well for both temperature and humidity variations for periods and places of overlap, although the average warming over land is larger for the fully sampled ERA data than for the spatially and temporally incomplete CRUTEM3 data. Near-surface specific humidity varies similarly over land and sea, suggesting that the recent reduction in relative humidity over land may be due to limited moisture supply from the oceans, where evaporation has been limited by sea surface temperatures that have not risen in concert with temperatures over land. Continental precipitation from the reanalyses is compared with a new gauge-based Global Precipitation Climatology Centre (GPCC) data set, with the combined gauge and satellite products of the Global Precipitation Climatology Project (GPCP) and the Climate Prediction Center (CPC), Merged Analysis of Precipitation (CMAP), and with CPC's independent gauge analysis of precipitation over land (PREC/L). The reanalyses agree best with the new GPCC and latest GPCP data sets, with ERA-Interim significantly better than ERA-40 at capturing monthly variability. Shifts over time in the differences among the precipitation data sets make it difficult to assess their longer-term variations and any link with longer-term variations in humidity.

  20. Interannual Variations in Global Vegetation Phenology Derived from a Long Term AVHRR and MODIS Data Record

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Friedl, M. A.; Yu, Y.

    2013-12-01

    Land surface phenology metrics are widely retrieved from satellite observations at regional and global scales, and have been shown to be valuable for monitoring terrestrial ecosystem dynamics in response to extreme climate events and predicting biological responses to future climate scenarios. While the response of spring vegetation greenup to climate warming at mid-to-high latitudes is well-documented, understanding of diverse phenological responses to climate change over entire growing cycles and at broad geographic scales is incomplete. Many studies assume that the timing of individual phenological indicators in responses to climate forcing is independent of phenological events that occur at other times during the growing season. In this paper we use a different strategy. Specifically, we hypothesize that integrating sequences of key phenological indicators across growing seasons provides a more effective way to capture long-term variation in phenology in response to climate change. To explore this hypothesis we use global land surface phenology metrics derived from the Version 3 Long Term Vegetation Index Products from Multiple Satellite Data Records data set to examine interannual variations and trends in global land surface phenology from 1982-2010. Using daily enhanced vegetation index (EVI) data at a spatial resolution of 0.05 degrees, we model the phenological trajectory for each individual pixel using piecewise logistic models. The modeled trajectories were then used to detect phenological indicators including the onset of greenness increase, the onset of greenness maximum, the onset of greenness decrease, the onset of greenness minimum, and the growing season length, among others at global scale. The quality of land surface phenology detection for individual pixels was calculated based on metrics that characterize the EVI quality and model fits in annual time series at each pixel. Phenological indicators characterized as having good quality were then

  1. The compensation effects of temperature variation in long-term videometric measurement

    NASA Astrophysics Data System (ADS)

    Chao, Zhichao; Jiang, Guangwen; Fu, Sihua; Yu, Qifeng

    2015-08-01

    Temperature variations will affect the geometric and optical characteristics of the camera and lens in the videometric system, especially when the optical systems are working in a long period. The paper presents an analysis of the image drift caused by temperature variations and the corresponding temperature compensation method. Firstly, image drift model is established based on the pinhole camera model; then two simplified models are introduced by analyzing the coupling relations between the variations of camera parameters and temperature; furthermore, influence of temperature changes on camera parameters were modeled and calibrated; pose estimation experiments as well as temperature compensations are also conducted in deformation measurements, and the results prove the feasibility and efficiency of the proposed models.

  2. Plastic responses in the metabolome and functional traits of maize plants to temperature variations.

    PubMed

    Sun, C X; Gao, X X; Li, M Q; Fu, J Q; Zhang, Y L

    2016-03-01

    Environmentally inducible phenotypic plasticity is a major player in plant responses to climate change. However, metabolic responses and their role in determining the phenotypic plasticity of plants that are subjected to temperature variations remain poorly understood. The metabolomic profiles and metabolite levels in the leaves of three maize inbred lines grown in different temperature conditions were examined with a nuclear magnetic resonance metabolomic technique. The relationship of functional traits to metabolome profiles and the metabolic mechanism underlying temperature variations were then explored. A comparative analysis showed that during heat and cold stress, maize plants shared common plastic responses in biomass accumulation, carbon, nitrogen, sugars, some amino acids and compatible solutes. We also found that the plastic response of maize plants to heat stress was different from that under cold stress, mainly involving biomass allocation, shikimate and its aromatic amino acid derivatives, and other non-polar metabolites. The plastic responsiveness of functional traits of maize lines to temperature variations was low, while the metabolic responsiveness in plasticity was high, indicating that functional and metabolic plasticity may play different roles in maize plant adaptation to temperature variations. A linear regression analysis revealed that the maize lines could adapt to growth temperature variations through the interrelation of plastic responses in the metabolomes and functional traits, such as biomass allocation and the status of carbon and nitrogen. We provide valuable insight into the plastic response strategy of maize plants to temperature variations that will permit the optimisation of crop cultivation in an increasingly variable environment. PMID:26280133

  3. Plastic responses in the metabolome and functional traits of maize plants to temperature variations.

    PubMed

    Sun, C X; Gao, X X; Li, M Q; Fu, J Q; Zhang, Y L

    2016-03-01

    Environmentally inducible phenotypic plasticity is a major player in plant responses to climate change. However, metabolic responses and their role in determining the phenotypic plasticity of plants that are subjected to temperature variations remain poorly understood. The metabolomic profiles and metabolite levels in the leaves of three maize inbred lines grown in different temperature conditions were examined with a nuclear magnetic resonance metabolomic technique. The relationship of functional traits to metabolome profiles and the metabolic mechanism underlying temperature variations were then explored. A comparative analysis showed that during heat and cold stress, maize plants shared common plastic responses in biomass accumulation, carbon, nitrogen, sugars, some amino acids and compatible solutes. We also found that the plastic response of maize plants to heat stress was different from that under cold stress, mainly involving biomass allocation, shikimate and its aromatic amino acid derivatives, and other non-polar metabolites. The plastic responsiveness of functional traits of maize lines to temperature variations was low, while the metabolic responsiveness in plasticity was high, indicating that functional and metabolic plasticity may play different roles in maize plant adaptation to temperature variations. A linear regression analysis revealed that the maize lines could adapt to growth temperature variations through the interrelation of plastic responses in the metabolomes and functional traits, such as biomass allocation and the status of carbon and nitrogen. We provide valuable insight into the plastic response strategy of maize plants to temperature variations that will permit the optimisation of crop cultivation in an increasingly variable environment.

  4. Agricultural Management Practices Explain Variation in Global Yield Gaps of Major Crops

    NASA Astrophysics Data System (ADS)

    Mueller, N. D.; Gerber, J. S.; Ray, D. K.; Ramankutty, N.; Foley, J. A.

    2010-12-01

    The continued expansion and intensification of agriculture are key drivers of global environmental change. Meeting a doubling of food demand in the next half-century will further induce environmental change, requiring either large cropland expansion into carbon- and biodiversity-rich tropical forests or increasing yields on existing croplands. Closing the “yield gaps” between the most and least productive farmers on current agricultural lands is a necessary and major step towards preserving natural ecosystems and meeting future food demand. Here we use global climate, soils, and cropland datasets to quantify yield gaps for major crops using equal-area climate analogs. Consistent with previous studies, we find large yield gaps for many crops in Eastern Europe, tropical Africa, and parts of Mexico. To analyze the drivers of yield gaps, we collected sub-national agricultural management data and built a global dataset of fertilizer application rates for over 160 crops. We constructed empirical crop yield models for each climate analog using the global management information for 17 major crops. We find that our climate-specific models explain a substantial amount of the global variation in yields. These models could be widely applied to identify management changes needed to close yield gaps, analyze the environmental impacts of agricultural intensification, and identify climate change adaptation techniques.

  5. Incorporating Temperature-driven Seasonal Variation in Survival, Growth, and Reproduction Models for Small Fish

    EPA Science Inventory

    Seasonal variation in survival and reproduction can be a large source of prediction uncertainty in models used for conservation and management. A seasonally varying matrix population model is developed that incorporates temperature-driven differences in mortality and reproduction...

  6. Ultra-low-voltage MTCMOS/SIMOX technology hardened to temperature variation

    NASA Astrophysics Data System (ADS)

    Douseki, Takakuni; Harada, Mitsuru; Tsuchiya, Toshiaki

    1997-04-01

    A novel multi-threshold CMOS (MTCMOS) circuit which offers the advantage of less variation in leakage current and delay time over a wide temperature range is described. It is shown that MTCMOS/SIMOX technology, which uses a SIMOX device and combines fully depleted low-threshold MOSFETs and partially depleted high-threshold MOSFETs, can reduce variation of circuit performance due to changes in the operating temperature. To evaluate the variation in circuit performance, models of the leakage-current and the delay-time including operating temperature are derived. Calculations using the models verify that the MTCMOS/SIMOX device with threshold voltages immune to temperature changes reduces the variation. This is also confirmed by an evaluation of a gate-chain TEG designed and fabricated with 0.25 μm MTCMOS/SIMOX technology.

  7. Multi-Decadal Aerosol Variations from 1980 to 2009: A Perspective from Observations and a Global Model

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, T.; Tan, Q.; Prospero, J. M.; Kahn, R. A.; Remer, L. A.; Yu, H.; Sayer, A. M.; Bian, H.; Geogdzhayev, I. V.; Holben, B. N.; Howell, S. G.; Huebert, B. J.; Hsu, N. C.; Kim, D.; Kucsera, T. L.; Levy, R. C.; Mishchenko, M. I.; Pan, X.; Quinn, P. K.; Schuster, G. L.; Streets, D. G.; Strode, S. A.; Torres, O.; Zhao, X.-P.

    2014-01-01

    Aerosol variations and trends over different land and ocean regions during 1980-2009 are analyzed with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model and observations from multiple satellite sensors and ground-based networks. Excluding time periods with large volcanic influences, the tendency of aerosol optical depth (AOD) and surface concentration over polluted land regions is consistent with the anthropogenic emission changes.The largest reduction occurs over Europe, and regions in North America and Russia also exhibit reductions. On the other hand, East Asia and South Asia show AOD increases, although relatively large amount of natural aerosols in Asia makes the total changes less directly connected to the pollutant emission trends. Over major dust source regions, model analysis indicates that the dust emissions over the Sahara and Sahel respond mainly to the near-surface wind speed, but over Central Asia they are largely influenced by ground wetness. The decreasing dust trend in the tropical North Atlantic is most closely associated with the decrease of Sahel dust emission and increase of precipitation over the tropical North Atlantic, likely driven by the sea surface temperature increase. Despite significant regional trends, the model-calculated global annual average AOD shows little changes over land and ocean in the past three decades, because opposite trends in different regions cancel each other in the global average. This highlights the need for regional-scale aerosol assessment, as the global average value conceals regional changes, and thus is not sufficient for assessing changes in aerosol loading.

  8. Influence of topography on the temperature variation around the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Kubokawa, H.; Masaki, S.; Fujiwara, M.; Suzuki, J.

    2015-12-01

    Temperature variations in the Tropical Tropopause Layer (TTL) are an important factor for dehydration in the UTLS region. It is known that Kelvin waves induce large temperature variations in the TTL. We investigated the temperature variations in the TTL using both numerical data produced by the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) and various observational data including satellite data (the Constellation Observing System for Meteorology, Ionosphere, and Climate; COSMIC), the reanalysis data of different resolution (ERA-40-interim, NCEP-CFSR, MERRA, YOTC-ECMWF), and radiosonde data for the Cooperative Indian Ocean experiment on intra-seasonal variability in the Year 2011 (CINDY). We found that all the data shows that the temperature variations become larger over the mountainous regions of the Indonesian maritime continent than over the oceanic regions and that the large temperature variations are associated with Kelvin waves. As, the horizontal resolution of the reanalysis becomes higher, the standard deviations of the TTL temperature near the mountains became larger. When Kelvin waves passed over the Indonesian maritime continent, the amplitude of temperature becomes about 2 K larger over the mountainous regions. The power spectrum for the periods between 7 days and 12 days was larger over the mountainous regions compared with that over the ocean. The sensitivity study using the stretch-NICAM shows that the height of mountains clearly affect the amplitude of temperature near the TTL.

  9. Use of global positioning system measurements to determine geocentric coordinates and variations in Earth orientation

    NASA Technical Reports Server (NTRS)

    Malla, R. P.; Wu, S.-C.; Lichten, S. M.

    1993-01-01

    Geocentric tracking station coordinates and short-period Earth-orientation variations can be measured with Global Positioning System (GPS) measurements. Unless calibrated, geocentric coordinate errors and changes in Earth orientation can lead to significant deep-space tracking errors. Ground-based GPS estimates of daily and subdaily changes in Earth orientation presently show centimeter-level precision. Comparison between GPS-estimated Earth-rotation variations, which are the differences between Universal Time 1 and Universal Coordinated Time (UT1-UTC), and those calculated from ocean tide models suggests that observed subdaily variations in Earth rotation are dominated by oceanic tidal effects. Preliminary GPS estimates for the geocenter location (from a 3-week experiment) agree with independent satellite laser-ranging estimates to better than 10 cm. Covariance analysis predicts that temporal resolution of GPS estimates for Earth orientation and geocenter improves significantly when data collected from low Earth-orbiting satellites as well as from ground sites are combined. The low Earth GPS tracking data enhance the accuracy and resolution for measuring high-frequency global geodynamical signals over time scales of less than 1 day.

  10. Variational quality control of hydrographic profile data with non-Gaussian errors for global ocean variational data assimilation systems

    NASA Astrophysics Data System (ADS)

    Storto, Andrea

    2016-08-01

    Quality control procedures aiming at identifying observations suspected of gross errors are an important component of modern ocean data assimilation systems. On the one hand, assimilating observations whose departures from the background state are large may result in detrimental analyses and compromise the stability of the ocean analysis system. On the other hand, the rejection of these observations may prevent the analysis from ingesting useful information, especially in areas of large variability. In this work, we investigate the quality control of in-situ hydrographic profiles through modifying the probability density function (PDF) of the observational errors and relaxing the assumption of Gaussian PDF. The new PDF is heavier-tailed than Gaussian, thus accommodating the assimilation of observations with large misfits, albeit with smaller weight given to them in the analysis. This implies a different observational term in the analysis equation, and an adaptive quality control procedure based on the innovation statistics themselves. Implemented in a global ocean variational data assimilation system at moderate horizontal resolution, the scheme proves robust and successful in assimilating more observations with respect to the simpler background quality check scheme. This leads to better skill scores against both conventional and satellite observing systems. This approach proves superior also to the case where no quality control is considered. Furthermore, the implementation considers switching on the modified cost function at the 10th iteration of the minimization so that innovation statistics are based on a good approximation of the analysis. Neglecting this strategy and turning on the variational quality control since the beginning of the minimization exhibits worse scores, qualitatively similar to those of the experiment without quality control, suggesting that in this case quality control procedures are too gentle. A specific study investigating the upper

  11. Synchronized dipole-like oscillations in global Sea Surface Temperature Anomaly (SSTA)

    NASA Astrophysics Data System (ADS)

    Oh, J.; Rial, J. A.

    2013-12-01

    This study investigates dipole-like oscillations in the sea surface temperature anomaly (SSTA), using reconstructed datasets from 1900 to 2011. Previous studies have explored the existence of dipole modes and their effects on local climate in their respective ocean basins. We have found seventeen, globally distributed, dipole-like, coupled oscillations (including four with Niño 3.4, and distinct from previously suggested dipoles), This founding is based on the direct comparison of global ocean SSTA, implemented by cross correlation coefficients in a 2 degree by 2 degree grid - 10988 points over global ocean - at annual, seasonal, and monthly scales. The dipole modes exist persistently at various time domains, though a few of them show a seasonally-dependent coupling strength. We discuss the specifics of these variations of modes, on both a seasonal and monthly scale. The dipole locations identified by this study are partially compatible with the results from Empirical orthogonal function (EOF) analysis. However, in most cases, EOF analysis fails to find the exact anomaly centers of the dipoles, which are synchronized by a Π/2 phase difference, and show maximum correlation coefficients there. It is necessary to look at the actual time series over the dipole regions to filter out any artifact generated by the EOF analysis. From the detected dipole modes, a dipole mode index (DMI) is defined as the difference between the first principal components of SSTA over 9 grid points around the detected anomaly centers. We investigate possible causes and effects of the dipoles, comparing the defined DMI with sea level pressure (SLP), wind, and other climate indices such as ENSO, PDO, AMO, NAO, and NPI. The DMI is also used to define the characteristics of each dipole, including whether they are synchronized to each other or oscillating independently. This study's goal is to create a better understanding and definition of the globally distributed teleconnections of the SSTA

  12. Seasonal variations in Titan's stratosphere observed with Cassini/CIRS: temperature, trace molecular gas and aerosol mixing ratio profiles

    NASA Astrophysics Data System (ADS)

    Vinatier, S.; Bézard, B.; Anderson, C.; Teanby, N.; Lebonnois, S.; Rannou, P.; de Kok, R.; T. CIRS Team

    2013-09-01

    Titan's northern spring equinox occurred in August 2009. General Circulation Models (e.g. [1]) predict strong modifications of the global circulation in this period, with formation of two circulation cells instead of the pole-to-pole cell that occurred during northern winter. This winter single cell, which had its descending branch at the north pole, was at the origin of the enrichment of molecular abundances and high stratopause temperatures observed by Cassini/CIRS at high northern latitudes (e.g., [2], [3], [4], [5]). The predicted dynamical seasonal variations after the equinox have strong impact on the spatial distributions of trace gas, temperature and aerosol abundances. We will present here an analysis of CIRS limbgeometry datasets acquired in 2010, 2011 and 2012 that we used to monitor the seasonal evolution of the vertical profiles of temperature, molecular (C2H2, C2H6, HCN, ...) and aerosol abundances.

  13. Similar negative impacts of temperature on global wheat yield estimated by three independent methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  14. Correlation between total solar irradiance and global land temperatures for the last 120 years

    NASA Astrophysics Data System (ADS)

    Varonov, A.; Shopov, Y. Y.

    2016-02-01

    We analyze the solar impact on one of the main Earth climate system components—the land-near-surface air temperature—during the past 120 years. Using statistical analysis, a correlation between the variations of the total solar irradiance and of the annual-mean land-near-surface air temperatures was found. An unknown time lag between both data sets was expected to be present due to the complexity of the Earth's climate system leading to a delayed response to changes in influencing factors. We found the best correlation with coefficient over 90% for a 14-year shift of the annual mean land temperature record ahead with data before 1970, while the same comparison with data until 2006 yields 61% correlation. These results show the substantially higher influence of the total solar irradiance on the global land temperatures before 1970. The decline of this influence during the last 40 years could be attributed to the increasing concentration of anthropogenic greenhouse gases in the Earth's atmosphere.

  15. Is global warming affecting cave temperatures? Experimental and model data from a paradigmatic case study

    NASA Astrophysics Data System (ADS)

    Domínguez-Villar, David; Lojen, Sonja; Krklec, Kristina; Baker, Andy; Fairchild, Ian J.

    2015-08-01

    This research focuses on the mechanisms that transfer the variations in surface atmospheric temperature into caves to evaluate whether they record the warming trend of recent decades. As a study case, we use the data from a hall in Postojna Cave (Slovenia), which was monitored from 2009 to 2013. The low-frequency thermal variability of this cave chamber is dominated by the conduction of heat from the surface through the bedrock. We implemented a thermal conduction model that reproduces low-frequency thermal gradients similar to those measured in the cave. At the 37 m depth of this chamber, the model confirms that the bedrock is already recording the local expression of global warming with a delay of 20-25 years, and predicts a cave warming during the coming decades with a mean rate of 0.015 ± 0.004 C year-1. However, because of the transfer of surface atmosphere thermal variability depends on the duration of the oscillations, the thermal anomalies with periods 7-15 years in duration have delay times <10 years at the studied hall. The inter-annual variability of the surface atmospheric temperature is recorded in this cave hall, although due to the different delay and amplitude attenuation that depends on the duration of the anomalies, the cave temperature signal differs significantly from that at the surface. As the depth of the cave is a major factor in thermal conduction, this is a principal control on whether or not a cave has already recorded the onset of global warming.

  16. Global perspectives in hospitalized heart failure: regional and ethnic variation in patient characteristics, management, and outcomes.

    PubMed

    Ambrosy, Andrew P; Gheorghiade, Mihai; Chioncel, Ovidiu; Mentz, Robert J; Butler, Javed

    2014-12-01

    Heart failure (HF) is a public health problem of global proportions afflicting more than 25 million patients worldwide. Despite stable or declining per capita hospitalization rates in the USA and several European countries, there are over one million hospitalizations for HF annually in the USA, with similar numbers in Europe, accounting for 6.5 million hospital days and the majority of the approximately $40 billion spent each year on HF-related care. Moreover, clinical trial data suggest that post-discharge survival and readmissions have largely remained unchanged. Thus, understanding geographic and ethnic variations in HF is essential to formulating public policy at the local, national, regional, and international levels and setting the agenda for basic, translational, and clinical research endeavors. This paper aims to describe regional and ethnic variations in patient characteristics, management, and outcomes in hospitalized HF.

  17. Global petrologic variations on the moon: a ternary-diagram approach.

    USGS Publications Warehouse

    Davis, P.A.; Spudis, P.D.

    1987-01-01

    A ternary-diagram approach for determination of global petrologic variations on the lunar surface is presented that incorporates valuable improvements in our previous method of using geochemical variation diagrams. Our results are as follows: 1) the highlands contain large areas of relatively pure ferroan anorthosite; 2) the average composition of the upper lunar crust is represented by an 'anorthositic gabbro' composition; 3) KREEP/Mg-suite rocks are a minor fraction of the upper lunar crust; 4) within the farside highlands, areas of KREEP/Mg-suite rocks coincide mostly with areas of crustal thinning; 5) portions of the E limb and farside highlands have considerable amounts of a mafic, chondritic Th/Ti component (like mare basalt) whose occurrences coincide with mapped concentrations of light plains that display dark-halo craters.- from Authors

  18. Automatic polyp detection using global geometric constraints and local intensity variation patterns.

    PubMed

    Tajbakhsh, Nima; Gurudu, Suryakanth R; Liang, Jianming

    2014-01-01

    This paper presents a new method for detecting polyps in colonoscopy. Its novelty lies in integrating the global geometric constraints of polyps with the local patterns of intensity variation across polyp boundaries: the former drives the detector towards the objects with curvy boundaries, while the latter minimizes the misleading effects of polyp-like structures. This paper makes three original contributions: (1) a fast and discriminative patch descriptor for precisely characterizing patterns of intensity variation across boundaries, (2) a new 2-stage classification scheme for accurately excluding non-polyp edges from an overcomplete edge map, and (3) a novel voting scheme for robustly localizing polyps from the retained edges. Evaluations on a public database and our own videos demonstrate that our method is promising and outperforms the state-of-the-art methods. PMID:25485377

  19. Neural field dynamics under variation of local and global connectivity and finite transmission speed

    NASA Astrophysics Data System (ADS)

    Qubbaj, Murad R.; Jirsa, Viktor K.

    2009-12-01

    Spatially continuous networks with heterogeneous connections are ubiquitous in biological systems, in particular neural systems. To understand the mutual effects of locally homogeneous and globally heterogeneous connectivity, we investigate the stability of the steady state activity of a neural field as a function of its connectivity. The variation of the connectivity is implemented through manipulation of a heterogeneous two-point connection embedded into the otherwise homogeneous connectivity matrix and by variation of the connectivity strength and transmission speed. Detailed examples including the Ginzburg-Landau equation and various other local architectures are discussed. Our analysis shows that developmental changes such as the myelination of the cortical large-scale fiber system generally result in the stabilization of steady state activity independent of the local connectivity. Non-oscillatory instabilities are shown to be independent of any influences of time delay.

  20. Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations.

    PubMed

    Zidon, Royi; Tsueda, Hirotsugu; Morin, Efrat; Morin, Shai

    2016-06-01

    The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. This framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain), and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid-21st century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current

  1. Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations.

    PubMed

    Zidon, Royi; Tsueda, Hirotsugu; Morin, Efrat; Morin, Shai

    2016-06-01

    The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. This framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain), and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid-21st century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current

  2. A global meta-analysis of the relative extent of intraspecific trait variation in plant communities.

    PubMed

    Siefert, Andrew; Violle, Cyrille; Chalmandrier, Loïc; Albert, Cécile H; Taudiere, Adrien; Fajardo, Alex; Aarssen, Lonnie W; Baraloto, Christopher; Carlucci, Marcos B; Cianciaruso, Marcus V; de L Dantas, Vinícius; de Bello, Francesco; Duarte, Leandro D S; Fonseca, Carlos R; Freschet, Grégoire T; Gaucherand, Stéphanie; Gross, Nicolas; Hikosaka, Kouki; Jackson, Benjamin; Jung, Vincent; Kamiyama, Chiho; Katabuchi, Masatoshi; Kembel, Steven W; Kichenin, Emilie; Kraft, Nathan J B; Lagerström, Anna; Bagousse-Pinguet, Yoann Le; Li, Yuanzhi; Mason, Norman; Messier, Julie; Nakashizuka, Tohru; Overton, Jacob McC; Peltzer, Duane A; Pérez-Ramos, I M; Pillar, Valério D; Prentice, Honor C; Richardson, Sarah; Sasaki, Takehiro; Schamp, Brandon S; Schöb, Christian; Shipley, Bill; Sundqvist, Maja; Sykes, Martin T; Vandewalle, Marie; Wardle, David A

    2015-12-01

    Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies. PMID:26415616

  3. Ambient temperature as a contributor to kidney stone formation: implications of global warming.

    PubMed

    Fakheri, Robert J; Goldfarb, David S

    2011-06-01

    Nephrolithiasis is a common disease across the world that is becoming more prevalent. Although the underlying cause for most stones is not known, a body of literature suggests a role of heat and climate as significant risk factors for lithogenesis. Recently, estimates from computer models predicted up to a 10% increase in the prevalence rate in the next half century secondary to the effects of global warming, with a coinciding 25% increase in health-care expenditures. Our aim here is to critically review the medical literature relating stones to ambient temperature. We have categorized the body of evidence by methodology, consisting of comparisons between geographic regions, comparisons over time, and comparisons between people in specialized environments. Although most studies are confounded by other factors like sunlight exposure and regional variation in diet that share some contribution, it appears that heat does play a role in pathogenesis in certain populations. Notably, the role of heat is much greater in men than in women. We also hypothesize that the role of a significant human migration (from rural areas to warmer, urban locales beginning in the last century and projected to continue) may have a greater impact than global warming on the observed worldwide increasing prevalence rate of nephrolithiasis. At this time the limited data available cannot substantiate this proposed mechanism but further studies to investigate this effect are warranted.

  4. Diagnostics of a cause-effect relation between solar activity and the Earth's global surface temperature

    NASA Astrophysics Data System (ADS)

    Mokhov, I. I.; Smirnov, D. A.

    2008-06-01

    The influence of solar activity on the Earth’s global surface temperature (GST) was quantified. The method for estimation of the Granger causality was used, with analysis of the improvement of the prediction of one process by using data from another process as compared to autoprediction. Two versions of reconstructions of the solar flux variations associated with solar activity were used, according to Hoyt et al. [1997] for 1680 1992 (data H) and according to Lean et al. [2005] for 1610 2005 (data L). In general, the estimation results for the two reconstructions are reasonably well consistent. A significant influence of solar activity on GST with a positive sign was found for two periods, from the late 19th century to the late 1930s and from the latter half of the 1940s to the early 1990s, with no inertia or time delay. In these periods, up to 8 and 25% of the variance of the GST change, respectively, can be attributed to solar activity variations. The solar influence increased in the 1980s to the early 1990s according to data H and began to decrease in the latter half of the 1980s according to data L.

  5. Subtle variation in ambient room temperature influences the expression of social cognition.

    PubMed

    Vigil, Jacob M; Swartz, Tyler J; Rowell, Lauren N

    2013-10-01

    Social signaling models predict that subtle variation in climatic temperature induces systematic changes in expressed cognition. An experiment showed that perceived room temperature was associated with variability in self-descriptions, social reactions of others, and desiring differing types of social networks. The findings reflect the tendency to inflate capacity demonstrations in warmer climates as a result of the social networking opportunities they enable.

  6. Climate change record in subsurface temperatures: A global perspective

    PubMed

    Pollack; Huang; Shen

    1998-10-01

    Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5 degreesC and that the 20th century has been the warmest of the past five centuries. The subsurface temperatures also indicate that Earth's mean surface temperature has increased by about 1.0 degreesC over the past five centuries. The geothermal data offer an independent confirmation of the unusual character of 20th-century climate that has emerged from recent multiproxy studies.

  7. Regional synchrony of temperature variation and internal wave forcing along the Florida Keys reef tract

    NASA Astrophysics Data System (ADS)

    Leichter, James J.; Stokes, M. Dale; Vilchis, L. Ignacio; Fiechter, Jerome

    2014-01-01

    Analysis of 10 year temperature records collected along the Florida Keys reef tract (FLKRT) reveals strong, regional-scale synchrony in high-frequency temperature variation suggestive of internal wave forcing at predominately semidiurnal frequencies. In each year and at all sites, the amplitude of semidiurnal temperature variation was greatest from March to September, and markedly lower from October to February. Comparisons of the semidiurnal component of the temperature variation among sites suggest complex patterns in the arrival of internal waves, with highest cross correlation among closely spaced sites and synchrony in periods of enhanced internal wave activity across the length of the FLKRT, particularly in summer. The periods of enhanced semidiurnal temperature variation at the 20 and 30 m isobaths on the reef slopes appear to be associated with the dynamics of the Florida Current and the onshore movement of warm fronts preceding the passage of Florida Current frontal eddies. Regional-scale satellite altimetry observations suggest temporal linkages to sea surface height anomalies in the Loop Current (upstream of the Florida Current) and setup of the Tortugas Gyre. The synchronized forcing of cool water onto the reef slope sites across the FLKRT is likely to affect physiological responses to temperature variation in corals and other ectothermic organisms, as well as larval transport and nutrient dynamics with the potential for regionally coherent pulses of larvae and nutrients arriving on reef slopes across the FLKRT.

  8. A Comprehensive Database for the Most Commonly Measured Paleoceanographic Proxies: Evaluating Global Carbon Burial Variations over the Last Deglaciation

    NASA Astrophysics Data System (ADS)

    Cartapanis, O. A.; Galbraith, E. D.; Bianchi, D.

    2014-12-01

    The paleoceanographic community has measured physical and chemical properties of thousands of sediment cores, in order to reconstruct past oceanic conditions across a wide range of timescales. Most of these datasets were archived in online data repositories in order to facilitate later analysis. However, the diversity of proxy types and heterogeneous reporting standards have hindered the analysis of globally distributed paleoceanographic time series, despite the tremendous potential utility of large datasets. In order for the existing archives of paleoceanographic data to contribute towards important unanswered issues, the datasets must be readily accessible in an organized structure, with an appropriate unified age model for each sediment site. Here we present a comprehensive database, built using MATLAB structure, for the most commonly measured proxies in marine sediment cores and surface sediment. These include the concentrations of carbonate, organic matter and opal, density of the sediment, the oxygen and carbon isotopic composition of benthic and planktonic foraminifera, sea surface temperature estimates, as well as chronological constrains. The records were downloaded from PANGAEA and NOAA databases and multiple records from the same sediment core were regrouped, allowing age models to be shared between records. The resulting database consists of more than 30,000 sites, facilitating rapid and accurate mapping of sediment composition for selected time periods, and retrieving and plotting time series. The greatest hurdle identified in building a unifi­ed dataproduct of this type is inconsistency in the reporting of depth measurements and chronological information. In our view, standardized reporting practices would greatly assist in developing global quantitative analysis, and requires community-wide action. We propose the development of a unified global sediment core registry, including metadata and chronological information for all marine sediment cores

  9. Recent Research toward Understanding Spatial, Temporal, and Climatic Variation in Stream Temperatures across the Northwest U.S.

    NASA Astrophysics Data System (ADS)

    Isaak, D.; Roper, B.; Luce, C.; Holden, Z.

    2012-12-01

    Global air temperature increases raise concerns about effects on thermal regimes of the Earth's rivers and streams. These concerns are acute in the Northwest U.S. due to legislatively mandated water quality standards and the importance of recreational and commercial fisheries for cold-water species such as salmon and trout. Efforts to study climate effects on stream thermal regimes are limited by sparse long-term monitoring records, resulting in a lack of information on historical spatial and temporal variation from which to measure departure. We present research from the last five years that begins to address these shortcomings, including: 1) estimation of stream warming rates in recent decades associated with long-term climate change (+0.11 °C/decade for mean annual temperatures; +0.22 °C/decade for summer temperatures), 2) development of an inexpensive protocol for monitoring full-year temperatures in dynamic mountain streams, 3) rapid expansion of an informal regional monitoring network from < 1,000 stream sites to > 3,000 sites in the last three years, 4) development and use of high-resolution (i.e., 100's of meters) air temperature microclimate models to understand variation in stream temperatures, 5) development of NorWeST, a comprehensive stream temperature database consisting of > 45,000 summers of temperature measurement at > 15,000 unique stream sites, and 6) use of new spatial statistical stream network models with NorWeST to krige predictions at unsampled locations and develop thermal information for most of the region's 350,000 stream kilometers. There is much yet to be learned regarding thermal regimes in rivers and streams but the accelerating pace of knowledge discovery driven by inexpensive sensors, computational improvements, geospatial technologies, and new analyses suggests that many important remaining unknowns will be resolved in the next five years.

  10. Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies.

    PubMed

    von Cramon-Taubadel, Noreen

    2011-12-01

    Variation in the masticatory behavior of hunter-gatherer and agricultural populations is hypothesized to be one of the major forces affecting the form of the human mandible. However, this has yet to be analyzed at a global level. Here, the relationship between global mandibular shape variation and subsistence economy is tested, while controlling for the potentially confounding effects of shared population history, geography, and climate. The results demonstrate that the mandible, in contrast to the cranium, significantly reflects subsistence strategy rather than neutral genetic patterns, with hunter-gatherers having consistently longer and narrower mandibles than agriculturalists. These results support notions that a decrease in masticatory stress among agriculturalists causes the mandible to grow and develop differently. This developmental argument also explains why there is often a mismatch between the size of the lower face and the dentition, which, in turn, leads to increased prevalence of dental crowding and malocclusions in modern postindustrial populations. Therefore, these results have important implications for our understanding of human masticatory adaptation.

  11. Effect of camera temperature variations on stereo-digital image correlation measurements.

    PubMed

    Pan, Bing; Shi, Wentao; Lubineau, Gilles

    2015-12-01

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30-50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  12. Temperature variations in the middle and upper stratosphere: 1979-1992

    SciTech Connect

    Lambeth, J.D.; Callis, L.B. |

    1994-10-01

    Temperature variations in the stratosphere from 1979 to 1992 are investigated using 365-day running mean of the National Meteorological Center gridded analysis temperature data. Significant variations are seen at all levels between 70 and 1 mbar. The middle stratosphere shows temperature peaks during 1982 and 1983. The upper stratosphere has significant temperature declines between 1 and 10 mbar from 1981 to 1984. Temperatures at all levels recover to near their prior values after 1984, with the 5-mbar temperatures requiring the greatest time to fully recover. The temperature declines at 1 mbar occur in both hemispheres, over all longitudes, and in every month of the year. The decreases are largest in the middle latitudes and the polar regions and during the fall and the winter months. Such temperature variations, which appear to be of natural origin, must be taken into consideration when searching for temperature trends caused by the increase of CO2 or other greenhouse gases which affect the radiative balance of the Earth-atmosphere system or stratospheric ozone.

  13. Modeled Seasonal Variations of Firn Density Induced by Steady State Surface Air Temperature Cycle

    NASA Technical Reports Server (NTRS)

    Jun, Li; Zwally, H. Jay; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Seasonal variations of firn density in ice-sheet firn layers have been attributed to variations in deposition processes or other processes within the upper firn. A recent high-resolution (mm scale) density profile, measured along a 181 m core from Antarctica, showed small-scale density variations with a clear seasonal cycle that apparently was not-related to seasonal variations in deposition or known near-surface processes (Gerland and others 1999). A recent model of surface elevation changes (Zwally and Li, submitted) produced a seasonal variation in firn densification, and explained the seasonal surface elevation changes observed by satellite radar altimeters. In this study, we apply our 1-D time-dependent numerical model of firn densification that includes a temperature-dependent formulation of firn densification based on laboratory measurements of grain growth. The model is driven by a steady-state seasonal surface temperature and a constant accumulation rate appropriate for the measured Antarctic ice core. The modeled seasonal variations in firn density show that the layers of snow deposited during spring to mid-summer with the highest temperature history compress to the highest density, and the layers deposited during later summer to autumn with the lowest temperature history compress to the lowest density. The initial amplitude of the seasonal difference of about 0.13 reduces to about 0.09 in five years and asymptotically to 0.92 at depth, which is consistent with the core measurements.

  14. Variations in geomagnetic field and temperature in Spain during the past millennium

    NASA Astrophysics Data System (ADS)

    Nachasova, I. E.; Burakov, K. S.; Pilipenko, O. V.; Markov, G. P.

    2015-07-01

    The archaeomagnetic studies are conducted for the collection of coated ceramic samples from the Albarracin archaeological monument in Spain dated to the 10-20th centuries A.D. The pattern of variations in geomagnetic field intensity during this time interval is identified. The behavior of geomagnetic intensity is dominated by a decreasing trend (from ˜80 to 40 μT). The variation with a characteristic time of a few hundred years is the most striking one. Investigation of the material from this collection by the method of rehydroxylation provided the temperature estimates for this region of Spain for the time interval of pottery production. The temperature variations generally tend to increase, while the main trend in the variations of geomagnetic intensity is decreasing. The time series of temperature and intensity of the main magnetic field contain variations with close characteristic times shifted in time so that the changes in temperature go somewhat ahead of the changes in the geomagnetic field. It was previously suggested to improve the accuracy and resolution of the obtained variations in the past magnetic field using the method of archaeomagnetic dating of the material from archaeological monuments. The method was tested by dating the pottery kiln material from the El Molon monument, Spain, with the use of the virtual geomagnetic pole curve based on the past magnetic field in the East Europe. The method proved to be quite efficient and promising for dating the archaeological material from all over Europe.

  15. Variation in surface air temperature of China during the 20th century

    NASA Astrophysics Data System (ADS)

    Soon, Willie; Dutta, Koushik; Legates, David R.; Velasco, Victor; Zhang, Weijia

    2011-10-01

    The 20th century surface air temperature (SAT) records of China from various sources are analyzed using data which include the recently released Twentieth Century Reanalysis Project dataset. Two key features of the Chinese records are confirmed: (1) significant 1920s and 1940s warming in the temperature records, and (2) evidence for a persistent multidecadal modulation of the Chinese surface temperature records in co-variations with both incoming solar radiation at the top of the atmosphere as well as the modulated solar radiation reaching ground surface. New evidence is presented for this Sun-climate link for the instrumental record from 1880 to 2002. Additionally, two non-local physical aspects of solar radiation-induced modulation of the Chinese SAT record are documented and discussed.Teleconnections that provide a persistent and systematic modulation of the temperature response of the Tibetan Plateau and/or the tropospheric air column above the Eurasian continent (e.g., 30°N-70°N; 0°-120°E) are described. These teleconnections may originate from the solar irradiance-Arctic-North Atlantic overturning circulation mechanism proposed by Soon (2009). Also considered is the modulation of large-scale land-sea thermal contrasts both in terms of meridional and zonal gradients between the subtropical western Pacific and mid-latitude North Pacific and the continental landmass of China. The Circum-global teleconnection (CGT) pattern of summer circulation of Ding and Wang (2005) provides a physical framework for study of the Sun-climate connection over East Asia. Our results highlight the importance of solar radiation reaching the ground and the concomitant importance of changes in atmospheric transparency or cloudiness or both in motivating a true physical explanation of any Sun-climate connection. We conclude that ground surface solar radiation is an important modulating factor for Chinese SAT changes on multidecadal to centennial timescales. Therefore, a

  16. Monitoring interannual variation in global crop yield using long-term AVHRR and MODIS observations

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyang; Zhang, Qingyuan

    2016-04-01

    Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) data have been extensively applied for crop yield prediction because of their daily temporal resolution and a global coverage. This study investigated global crop yield using daily two band Enhanced Vegetation Index (EVI2) derived from AVHRR (1981-1999) and MODIS (2000-2013) observations at a spatial resolution of 0.05° (∼5 km). Specifically, EVI2 temporal trajectory of crop growth was simulated using a hybrid piecewise logistic model (HPLM) for individual pixels, which was used to detect crop phenological metrics. The derived crop phenology was then applied to calculate crop greenness defined as EVI2 amplitude and EVI2 integration during annual crop growing seasons, which was further aggregated for croplands in each country, respectively. The interannual variations in EVI2 amplitude and EVI2 integration were combined to correlate to the variation in cereal yield from 1982-2012 for individual countries using a stepwise regression model, respectively. The results show that the confidence level of the established regression models was higher than 90% (P value < 0.1) in most countries in the northern hemisphere although it was relatively poor in the southern hemisphere (mainly in Africa). The error in the yield predication was relatively smaller in America, Europe and East Asia than that in Africa. In the 10 countries with largest cereal production across the world, the prediction error was less than 9% during past three decades. This suggests that crop phenology-controlled greenness from coarse resolution satellite data has the capability of predicting national crop yield across the world, which could provide timely and reliable crop information for global agricultural trade and policymakers.

  17. Unique genetic variation at a species' rear edge is under threat from global climate change

    PubMed Central

    Provan, Jim; Maggs, Christine A.

    2012-01-01

    Global climate change is having a significant effect on the distributions of a wide variety of species, causing both range shifts and population extinctions. To date, however, no consensus has emerged on how these processes will affect the range-wide genetic diversity of impacted species. It has been suggested that species that recolonized from low-latitude refugia might harbour high levels of genetic variation in rear-edge populations, and that loss of these populations could cause a disproportionately large reduction in overall genetic diversity in such taxa. In the present study, we have examined the distribution of genetic diversity across the range of the seaweed Chondrus crispus, a species that has exhibited a northward shift in its southern limit in Europe over the last 40 years. Analysis of 19 populations from both sides of the North Atlantic using mitochondrial single nucleotide polymorphisms (SNPs), sequence data from two single-copy nuclear regions and allelic variation at eight microsatellite loci revealed unique genetic variation for all marker classes in the rear-edge populations in Iberia, but not in the rear-edge populations in North America. Palaeodistribution modelling and statistical testing of alternative phylogeographic scenarios indicate that the unique genetic diversity in Iberian populations is a result not only of persistence in the region during the last glacial maximum, but also because this refugium did not contribute substantially to the recolonization of Europe after the retreat of the ice. Consequently, loss of these rear-edge populations as a result of ongoing climate change will have a major effect on the overall genetic diversity of the species, particularly in Europe, and this could compromise the adaptive potential of the species as a whole in the face of future global warming. PMID:21593035

  18. Unique genetic variation at a species' rear edge is under threat from global climate change.

    PubMed

    Provan, Jim; Maggs, Christine A

    2012-01-01

    Global climate change is having a significant effect on the distributions of a wide variety of species, causing both range shifts and population extinctions. To date, however, no consensus has emerged on how these processes will affect the range-wide genetic diversity of impacted species. It has been suggested that species that recolonized from low-latitude refugia might harbour high levels of genetic variation in rear-edge populations, and that loss of these populations could cause a disproportionately large reduction in overall genetic diversity in such taxa. In the present study, we have examined the distribution of genetic diversity across the range of the seaweed Chondrus crispus, a species that has exhibited a northward shift in its southern limit in Europe over the last 40 years. Analysis of 19 populations from both sides of the North Atlantic using mitochondrial single nucleotide polymorphisms (SNPs), sequence data from two single-copy nuclear regions and allelic variation at eight microsatellite loci revealed unique genetic variation for all marker classes in the rear-edge populations in Iberia, but not in the rear-edge populations in North America. Palaeodistribution modelling and statistical testing of alternative phylogeographic scenarios indicate that the unique genetic diversity in Iberian populations is a result not only of persistence in the region during the last glacial maximum, but also because this refugium did not contribute substantially to the recolonization of Europe after the retreat of the ice. Consequently, loss of these rear-edge populations as a result of ongoing climate change will have a major effect on the overall genetic diversity of the species, particularly in Europe, and this could compromise the adaptive potential of the species as a whole in the face of future global warming.

  19. [Variation patterns of soil wall temperature and heat flux in sunken solar greenhouse].

    PubMed

    Huang, Xue; Wang, Xiu-Feng; Wei, Min; Hou, Jia-Lin; Liu, Fu-Sheng; Li, Qing-Ming; Yang, Feng-Juan; Shi, Qing-Hua

    2013-06-01

    From December 2011 to March 2012, a consecutive test was conducted on the temperature and heat flux of different thickness of the soil backwall of sunken solar greenhouse in Shouguang of Shandong Province, East China, aimed to analyze the variation patterns of soil wall temperature and heat flux of the sunken solar greenhouse and to confirm the suitable wall thickness. In winter, the temperature and heat flux of the wall inner surface and outer surface varied over a wide range, which was in accordance with the variation trend of indoor and outdoor air temperature. Overall, the wall temperature decreased from the inner to the outer surface, and the layers of the inner wall with higher variation range of temperature and heat flux were more than those of the outer wall. The variation range of temperature and heat flux decreased gradually from the shallow layers to deep layers of the wall. In successive cloudy days, the temperature of each layer of inner wall decreased to different degrees, and the layers releasing heat to the indoor deepened constantly, whereas the heat in the layers of outer wall was mainly released to the outdoor. According to the variation patterns of temperature and heat flux in the wall, the wall from inside to outside could be divided into heat storage layer, transitional layer, and cold resistant layer, and their thickness was 0.8-1.0 m, 2.2-2.6 m, and 0.4-0.6 m, respectively, under the condition of the outer surface being covered. Without considering the transitional layer, the suitable thickness of the soil wall in Shouguang solar greenhouse would be 1.4-1.6 m.

  20. Interannual variation of global net radiation flux as measured from space

    NASA Astrophysics Data System (ADS)

    Zhu, Ping; Wild, Martin; Ruymbeke, Michel; Thuillier, Gérard; Meftah, Mustapha; Karatekin, Ozgur

    2016-06-01

    The global net radiation flux (NRF) in and out of the climate system at the top of the atmosphere (TOA) varies at interannual time scales, reflecting the complexity of the processes responsible for attaining global energy equilibrium. These processes are investigated in this study using the previously unexplored data acquired by a bolometric type sensor installed in the PICARD microsatellite. The obtained anomalies in the NRF (PICARD-NRF) are compared to the global NRF changes at the TOA measured by the Clouds and Earth's Radiant Energy System mission (CERES-NRF). The interanual PICARD-NRF is strongly correlated with the matching period CERES-NRF; the bootstrapped correlation at the 95%(+0.85 and +0.97) confidence intervals is +0.93. Consistency in the interannual variability in the NRF derived by two completely independent measurement systems enhances confidence in the estimated magnitude of these variations. To reveal the possible drivers of the NRF interannual variability, the NRF values were compared with the multivariate El Niño-Southern Oscillation index.

  1. Optimal Detection of Global Warming using Temperature Profiles

    NASA Technical Reports Server (NTRS)

    Leroy, Stephen S.

    1997-01-01

    Optimal fingerprinting is applied to estimate the amount of time it would take to detect warming by increased concentrations of carbon dioxide in monthly averages of temperature profiles over the Indian Ocean.

  2. Sex ratio variation shapes the ecological effects of a globally introduced freshwater fish.

    PubMed

    Fryxell, David C; Arnett, Heather A; Apgar, Travis M; Kinnison, Michael T; Palkovacs, Eric P

    2015-10-22

    Sex ratio and sexual dimorphism have long been of interest in population and evolutionary ecology, but consequences for communities and ecosystems remain untested. Sex ratio could influence ecological conditions whenever sexual dimorphism is associated with ecological dimorphism in species with strong ecological interactions. We tested for ecological implications of sex ratio variation in the sexually dimorphic western mosquitofish, Gambusia affinis. This species causes strong pelagic trophic cascades and exhibits substantial variation in adult sex ratios. We found that female-biased populations induced stronger pelagic trophic cascades compared with male-biased populations, causing larger changes to key community and ecosystem responses, including zooplankton abundance, phytoplankton abundance, productivity, pH and temperature. The magnitude of such effects indicates that sex ratio is important for mediating the ecological role of mosquitofish. Because both sex ratio variation and sexual dimorphism are common features of natural populations, our findings should encourage broader consideration of the ecological significance of sex ratio variation in nature, including the relative contributions of various sexually dimorphic traits to these effects. PMID:26490793

  3. Solar turbulence in earth's global and regional temperature anomalies.

    PubMed

    Scafetta, Nicola; Grigolini, Paolo; Imholt, Timothy; Roberts, Jim; West, Bruce J

    2004-02-01

    This paper presents a study of the influence of solar activity on the earth's temperature. In particular, we focus on the repercussion of the fluctuations of the solar irradiance on the temperature of the Northern and Southern hemispheres as well as on land and ocean regions. While solar irradiance data are not directly analyzed, we make use of a published solar irradiance reconstruction for long-time-scale fluctuations, and for short-time-scale fluctuations we hypothesize that solar irradiance and solar flare intermittency are coupled in such a way that the solar flare frequency fluctuations are stochastically equivalent to those of the solar irradiance. The analysis is based upon wavelet multiresolution techniques and scaling analysis methods for processing time series. The limitations of the correlation analysis applied to the short-time-scale fluctuations are discussed. The scaling analysis uses both the standard deviation and the entropy of the diffusion generated by the temperature signals. The joint use of these two scaling methods yields evidence of a Lévy component in the temporal persistence of the temperature fluctuations within the temporal range from a few weeks to a few years. This apparent Lévy persistence of the temperature fluctuations is found, by using an appropriate model, to be equivalent to the Lévy scaling of the solar flare intermittency. The mean monthly temperature data sets cover the period from 1856 to 2002. PMID:14995555

  4. Annual minimum temperature variations in early 21st century in Punjab, Pakistan

    NASA Astrophysics Data System (ADS)

    Jahangir, Misbah; Maria Ali, Syeda; Khalid, Bushra

    2016-01-01

    Climate change is a key emerging threat to the global environment. It imposes long lasting impacts both at regional and national level. In the recent era, global warming and extreme temperatures have drawn great interest to the scientific community. As in a past century considerable increase in global surface temperatures have been observed and predictions revealed that it will continue in the future. In this regard, current study mainly focused on analysis of regional climatic change (annual minimum temperature trends and its correlation with land surface temperatures in the early 21st century in Punjab) for a period of 1979-2013. The projected model data European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) has been used for eight Tehsils of Punjab i.e., annual minimum temperatures and annual seasonal temperatures. Trend analysis of annual minimum and annual seasonal temperature in (Khushab, Noorpur, Sargodha, Bhalwal, Sahiwal, Shahpur, Sillanwali and Chinoit) tehsils of Punjab was carried out by Regression analysis and Mann-Kendall test. Landsat 5 Thematic Mapper (TM) data was used in comparison with Model data for the month of May from the years 2000, 2009 and 2010. Results showed that no significant trends were observed in annual minimum temperature. A significant change was observed in Noorpur, Bhalwal, Shahpur, Sillanwali, Sahiwal, Chinoit and Sargodha tehsils during spring season, which indicated that this particular season was a transient period of time.

  5. Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M.

    PubMed

    Lutz, Ulrich; Posé, David; Pfeifer, Matthias; Gundlach, Heidrun; Hagmann, Jörg; Wang, Congmao; Weigel, Detlef; Mayer, Klaus F X; Schmid, Markus; Schwechheimer, Claus

    2015-10-01

    Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C) temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae. PMID:26492483

  6. Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M.

    PubMed

    Lutz, Ulrich; Posé, David; Pfeifer, Matthias; Gundlach, Heidrun; Hagmann, Jörg; Wang, Congmao; Weigel, Detlef; Mayer, Klaus F X; Schmid, Markus; Schwechheimer, Claus

    2015-10-01

    Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C) temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae.

  7. Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M

    PubMed Central

    Lutz, Ulrich; Posé, David; Pfeifer, Matthias; Gundlach, Heidrun; Hagmann, Jörg; Wang, Congmao; Weigel, Detlef; Mayer, Klaus F. X.; Schmid, Markus; Schwechheimer, Claus

    2015-01-01

    Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C) temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae. PMID:26492483

  8. Temporal and spatial variation of surface air temperature over the period of instrumental observations in the Arctic

    NASA Astrophysics Data System (ADS)

    Przybylak, Rajmund

    2000-05-01

    A detailed analysis of the spatial and temporal changes in mean seasonal and annual surface air temperatures over the period of instrumental observations in the Arctic is presented. In addition, the role of atmospheric circulation in controlling the instrumental and decadal-scale changes of air temperature in the Arctic is investigated. Mean monthly temperature and temperature anomalies data from 37 Arctic, 7 sub-Arctic and 30 grid-boxes were used for analysis.The presented analysis shows that the observed variations in air temperature in the real Arctic (defined on the basis of climatic as opposed to other criteria, e.g. astronomical or botanical) are in many aspects not consistent with the projected climatic changes computed by climatic models for the enhanced greenhouse effect. The highest temperatures since the beginning of instrumental observation occurred clearly in the 1930s and can be attributed to changes in atmospheric circulation. The second phase of contemporary global warming (after 1975) is, at most, weakly marked in the Arctic. For example, the mean rate of warming for the period 1991-1995 was 2-3 times lower in the Arctic than the global average. Temperature levels observed in Greenland in the last 10-20 years are similar to those observed in the 19th century.Increases of temperature in the Arctic are more significant in the warm half-year than in the cold half-year. This seasonal pattern in temperature change confirms the view that positive feedback mechanisms (e.g. sea-ice-albedo-temperature) as yet play only a small role in enhancing temperature in the Arctic. Hypotheses are presented to explain the lack of warming in the Arctic after 1975.It is shown that in some parts of the Arctic atmospheric circulation changes, in particular in the cold half-year, can explain up to 10-50% of the temperature variance. For Arctic temperature, the most important factor is a change in the atmospheric circulation over the North Atlantic. The influence of

  9. Effects of temperature variations on guided waves propagating in composite structures

    NASA Astrophysics Data System (ADS)

    Shoja, Siavash; Berbyuk, Viktor; Boström, Anders

    2016-04-01

    Effects of temperature on guided waves propagating in composite materials is a well-known problem which has been investigated in many studies. The majority of the studies is focused on effects of high temperature. Understanding the effects of low temperature has major importance in composite structures and components which are operating in cold climate conditions such as e.g. wind turbines operating in cold climate regions. In this study first the effects of temperature variations on guided waves propagating in a composite plate is investigated experimentally in a cold climate chamber. The material is a common material used to manufacture rotor blades of wind turbines. The temperature range is 25°C to -25°C and effects of temperature variations on amplitude and phase shift of the received signal are investigated. In order to apply the effects of lowering the temperature on the received signal, the Baseline Signal Stretch (BSS) method is modified and used. The modification is based on decomposing the signal into symmetric and asymmetric modes and applying two different stretch factors on each of them. Finally the results obtained based on the new method is compared with the results of application of BSS with one stretch factor and experimental measurements. Comparisons show that an improvement is obtained using the BSS with the mode decomposition method at temperature variations of more than 25°C.

  10. Eight-hundred years of summer temperature variations in the southeast of the Iberian Peninsula reconstructed from tree rings

    NASA Astrophysics Data System (ADS)

    Dorado Liñán, Isabel; Zorita, Eduardo; González-Rouco, Jesús Fidel; Heinrich, Ingo; Campello, Filipe; Muntán, Elena; Andreu-Hayles, Laia; Gutiérrez, Emilia

    2015-01-01

    July-to-October temperature variations are reconstructed for the last 800 years based on tree-ring widths from the Cazorla Range. Annual tree-ring width at this site has been found to be negatively correlated with temperature of the previous summer. This relationship is genuine, metabolically plausible, and cannot be explained as an indirect correlation mediated by hydroclimate. The resulting reconstruction (NCZ Tjaso ) represents the southernmost annually resolved temperature record based on tree-rings in Europe and provides detailed information on the regional climate evolution during the Late Holocene in the southeast of the Iberian Peninsula. The tree-ring based temperature reconstruction of Cazorla Range reveals predominantly warm summer temperatures during the transition between the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) from the 13th to the mid of the sixteenth century. The LIA spanned a slightly longer time (1500-1930 CE) than in other European summer temperature reconstructions from the Alps and Pyrenees. The twentieth century, though warmer than the preceding centuries, does not show unprecedented warmth in the last 800 years. Three ensembles of climate simulations conducted with two global atmosphere-ocean general circulation climate models (GCMs), considering different external forcings, were used for comparison: ECHO-G (Erik) and MPI-ESM (E1 and E2). Additionally, individual simulations were available from GCM included in the fifth Coupled Model Intercomparison Project, as well as single-forcing simulations performed with MPI-ESM. The comparison of the reconstructed and simulated temperatures revealed a close agreement of NCZ Tjaso with the simulations performed with total solar irradiance forcing with wider amplitude. Furthermore, the correlations with single-forcing simulations suggest volcanism as the main factor controlling preindustrial summer temperature variations in the Cazorla Range over the last five centuries. The

  11. Application of satellite data in variational analysis for global cyclonic systems

    NASA Technical Reports Server (NTRS)

    Achtemeier, G. L.

    1988-01-01

    The goal of the research is a variational data assimilation method that incorporates as dynamical constraints, the primitive equations for a moist, convectively unstable atmosphere and the radiative transfer equation. Variables to be adjusted include the three-dimensional vector wind, height, temperature, and moisture from rawinsonde data, and cloud-wind vectors, moisture, and radiance from satellite data. In order to facilitate thorough analysis of each of the model components, four variational models that divide the problem naturally according to increasing complexity were defined. The research performed during the second year fall into four areas: sensitivity studies involving Model 1; evaluation of Model 2; reformation of Model 1 for greater compatibility with Model 2; development of Model 3 (radiative transfer equation); and making the model more responsive to the observations.

  12. Analytical model for effect of temperature variation on PSF consistency in wavefront coding infrared imaging system

    NASA Astrophysics Data System (ADS)

    Feng, Bin; Shi, Zelin; Zhang, Chengshuo; Xu, Baoshu; Zhang, Xiaodong

    2016-05-01

    The point spread function (PSF) inconsistency caused by temperature variation leads to artifacts in decoded images of a wavefront coding infrared imaging system. Therefore, this paper proposes an analytical model for the effect of temperature variation on the PSF consistency. In the proposed model, a formula for the thermal deformation of an optical phase mask is derived. This formula indicates that a cubic optical phase mask (CPM) is still cubic after thermal deformation. A proposed equivalent cubic phase mask (E-CPM) is a virtual and room-temperature lens which characterizes the optical effect of temperature variation on the CPM. Additionally, a calculating method for PSF consistency after temperature variation is presented. Numerical simulation illustrates the validity of the proposed model and some significant conclusions are drawn. Given the form parameter, the PSF consistency achieved by a Ge-material CPM is better than the PSF consistency by a ZnSe-material CPM. The effect of the optical phase mask on PSF inconsistency is much slighter than that of the auxiliary lens group. A large form parameter of the CPM will introduce large defocus-insensitive aberrations, which improves the PSF consistency but degrades the room-temperature MTF.

  13. Interannual Variations and Trends in Global Land Surface Phenology Derived from Enhanced Vegetation Index During 1982-2010

    NASA Technical Reports Server (NTRS)

    Zhang, Xiaoyang; Tan, Bin; Yu, Yunyue

    2014-01-01

    Land swiace phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstmted to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This srudy detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel using piecewise logistic models, which was then used to detect the onset of greenness increase (OGI) and the length of vegetation growing season (GSL). Further, both overall interannual variations and pixel-based trends were examIned across Koeppen's climate regions for the periods of 1982-1999 and 2000-2010, respectively. The results show that OGI and OSL varied considerably during 1982-2010 across the globe. Generally, the interarmual variation could be more than a month in precipitation-controlled tropical and dry climates while it was mainly less than 15 days in temperature-controlled temperate, cold, and polar climates. OGI, overall, shifted early, and GSL was prolonged from 1982 to 2010 in most climate regions in North America and Asia while the consistently significant trends only occurred in cold climate and polar climate in North America. The overall trends in Europe were generally insignificant. Over South America, late OGI was consistent (particularly from 1982 to 1999) while either positive or negative OSL trends in a climate region were mostly reversed between the periods of 1982-1999 and 2000-2010. In the Northern Hemisphere of Africa, OGI trends were mostly insignificant, but prolonged GSL was evident over individual climate regions during the last 3

  14. Interannual variations and trends in global land surface phenology derived from enhanced vegetation index during 1982-2010

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyang; Tan, Bin; Yu, Yunyue

    2014-05-01

    Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel using piecewise logistic models, which was then used to detect the onset of greenness increase (OGI) and the length of vegetation growing season (GSL). Further, both overall interannual variations and pixel-based trends were examined across Koeppen's climate regions for the periods of 1982-1999 and 2000-2010, respectively. The results show that OGI and GSL varied considerably during 1982-2010 across the globe. Generally, the interannual variation could be more than a month in precipitation-controlled tropical and dry climates while it was mainly less than 15 days in temperature-controlled temperate, cold, and polar climates. OGI, overall, shifted early, and GSL was prolonged from 1982 to 2010 in most climate regions in North America and Asia while the consistently significant trends only occurred in cold climate and polar climate in North America. The overall trends in Europe were generally insignificant. Over South America, late OGI was consistent (particularly from 1982 to 1999) while either positive or negative GSL trends in a climate region were mostly reversed between the periods of 1982-1999 and 2000-2010. In the Northern Hemisphere of Africa, OGI trends were mostly insignificant, but prolonged GSL was evident over individual climate regions during the last 3

  15. Interannual variations and trends in global land surface phenology derived from enhanced vegetation index during 1982-2010.

    PubMed

    Zhang, Xiaoyang; Tan, Bin; Yu, Yunyue

    2014-05-01

    Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel using piecewise logistic models, which was then used to detect the onset of greenness increase (OGI) and the length of vegetation growing season (GSL). Further, both overall interannual variations and pixel-based trends were examined across Koeppen's climate regions for the periods of 1982-1999 and 2000-2010, respectively. The results show that OGI and GSL varied considerably during 1982-2010 across the globe. Generally, the interannual variation could be more than a month in precipitation-controlled tropical and dry climates while it was mainly less than 15 days in temperature-controlled temperate, cold, and polar climates. OGI, overall, shifted early, and GSL was prolonged from 1982 to 2010 in most climate regions in North America and Asia while the consistently significant trends only occurred in cold climate and polar climate in North America. The overall trends in Europe were generally insignificant. Over South America, late OGI was consistent (particularly from 1982 to 1999) while either positive or negative GSL trends in a climate region were mostly reversed between the periods of 1982-1999 and 2000-2010. In the Northern Hemisphere of Africa, OGI trends were mostly insignificant, but prolonged GSL was evident over individual climate regions during the last 3

  16. Interannual variations and trends in global land surface phenology derived from enhanced vegetation index during 1982-2010.

    PubMed

    Zhang, Xiaoyang; Tan, Bin; Yu, Yunyue

    2014-05-01

    Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel using piecewise logistic models, which was then used to detect the onset of greenness increase (OGI) and the length of vegetation growing season (GSL). Further, both overall interannual variations and pixel-based trends were examined across Koeppen's climate regions for the periods of 1982-1999 and 2000-2010, respectively. The results show that OGI and GSL varied considerably during 1982-2010 across the globe. Generally, the interannual variation could be more than a month in precipitation-controlled tropical and dry climates while it was mainly less than 15 days in temperature-controlled temperate, cold, and polar climates. OGI, overall, shifted early, and GSL was prolonged from 1982 to 2010 in most climate regions in North America and Asia while the consistently significant trends only occurred in cold climate and polar climate in North America. The overall trends in Europe were generally insignificant. Over South America, late OGI was consistent (particularly from 1982 to 1999) while either positive or negative GSL trends in a climate region were mostly reversed between the periods of 1982-1999 and 2000-2010. In the Northern Hemisphere of Africa, OGI trends were mostly insignificant, but prolonged GSL was evident over individual climate regions during the last 3

  17. Lateral Temperature Variations in Upwelling Limbs of the Asthenosphere and its Implications for Thermal Models of the Oceanic Lithosphere

    NASA Astrophysics Data System (ADS)

    Hamza, V. M.; Cardoso, R. R.

    2008-05-01

    Thermal models of the lithosphere proposed to date (the Half-Space Cooling and Plate models) have failed to provide satisfactory accounts of some of the important features in large-scale variations of oceanic heat flow. The systematic difference between model values and observational data have given rise to the so-called "oceanic heat flow paradox", for which no satisfactory solution has been found for over the last forty years. In the present work, we point out that this paradox is a consequence of the model assumption that lateral temperature variations are absent in the sublithospheric mantle. We propose a new thermal model of the oceanic lithosphere that can overcome such inconsistencies. Designated CMI, the new model assumes existence of lateral temperature variations in up-welling limbs of the asthenosphere, similar in character to those commonly observed in tectonothermal processes in the upper crust and in laboratory experiments of thermal plumes. CMI model simulations indicate that the thickness of the young lithosphere increases with distance from the ridge axis, at rates faster than those predicted by Half-Space Cooling and Plate models. As a result, the width of magma injection zone at mid-ocean ridges is relatively narrower in CMI model. Another noteworthy feature of the new model is its ability to provide vastly improved fits for observational heat flow data, in both young (ages less than 55 ma) and old (ages greater than 55 ma) oceanic lithosphere. More importantly, the improved fits to heat flow have been achieved without the need to invoke the ad-hoc hypothesis of large-scale hydrothermal circulation in stable ocean crust. Also, use of CMI model does not lead to artificial discontinuities in the temperature field of the lithosphere, as is the case with GDH reference models. The results of the CMI model provide a better understanding of the global heat flow variations and estimates of global heat loss. In particular, the model is capable of

  18. Predicting the variation in Echinogammarus marinus at its southernmost limits under global warming scenarios: can the sex-ratio make a difference?

    PubMed

    Guerra, Alexandra; Leite, Nuno; Marques, João Carlos; Ford, Alex T; Martins, Irene

    2014-01-01

    Understanding the environmental parameters that constrain the distribution of a species at its latitudinal extremes is critical for predicting how ecosystems react to climate change. Our first aim was to predict the variation in the amphipod populations of Echinogammarus marinus from the southernmost limit of its distribution under global warming scenarios. Our second aim was to test whether sex-ratio fluctuations - a mechanism frequently displayed by amphipods - respond to the variations in populations under altered climate conditions. To achieve these aims, scenarios were run with a validated model of E. marinus populations. Simulations were divided into: phase I - simulation of the effect of climate change on amphipod populations, and phase II - simulation of the effect of climate change on populations with male and female proportions. In both phases, temperature (T), salinity (S) and temperature and salinity (T-S) were tested. Results showed that E. marinus populations are highly sensitive to increases in temperature (>2 °C), which has adverse effects on amphipod recruitment and growth. Results from the climate change scenarios coupled with the sex-ratio fluctuations depended largely on the degree of female bias within population. Temperature increase of 2 °C had less impact on female-biased populations, particularly when conjugated with increases in salinity. Male-biased populations were highly sensitive to any variation in temperature and/or salinity; these populations exhibited a long-term decline in density. Simulations in which temperature increased more than 4 °C led to a continuous decline in the E. marinus population. According to this work, E. marinus populations at their southernmost limit are vulnerable to global warming. We anticipate that in Europe, temperature increases of 2 °C will incite a withdrawal of the population of 5°N from the amphipod species located at southernmost geographical borders. This effect is discussed in relation to the

  19. Inference of Global Mean Temperature Trend and Climate Change from MSU and AMSU

    NASA Technical Reports Server (NTRS)

    Prabhakara, Cuddapah; Iacovazzi, R. A., Jr.; Yoo, J.-M.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Microwave Sounding Unit (MSU) and Advanced MSU (AMSU) radiometers flown on the NOAA operational satellite series are potentially valuable as global temperature monitoring devices. Spencer and Christy pioneered the analysis of mid-tropospheric temperature, given by MSU Channel 2 (Ch 2) at 53.74 GHz, to derive the global temperature trend. Also, in addition to monitoring global temperature, these microwave radiometers have the potential to reveal interannual climate signals in tropics. We have analyzed the data of MSU Ch 2 and AMSU Ch 5 (53.6 GHz) from the NOAA operational satellites for the period 1980 to 2000, utilizing the NOAA calibration procedure. The data are corrected for the satellite orbital drift based on the temporal changes of the on-board warm blackbody temperature. From our analysis, we find that the global temperature increased at a rate of 0.13 +/- 0.05 Kdecade(sup -1) during 1980 to 2000. From an Empirical Orthogonal Function (EOF) analysis of the MSU global data, we find that the mid-tropospheric temperature in middle and high latitudes responds to the ENSO forcing during the Northern Hemisphere Winter in a distinct manner. This mid-latitude response is opposite in phase to that in the tropics. This result is in accord with simulations performed with an ECMWF global spectral model. This study shows a potential use of the satellite observations for climatic change.

  20. Different variation behaviors of resistivity for high-temperature-grown and low-temperature-grown p-GaN films

    NASA Astrophysics Data System (ADS)

    Jing, Yang; De-Gang, Zhao; De-Sheng, Jiang; Ping, Chen; Zong-Shun, Liu; Jian-Jun, Zhu; Ling-Cong, Le; Xiao-Jing, Li; Xiao-Guang, He; Li-Qun, Zhang; Hui, Yang

    2016-02-01

    Two series of p-GaN films grown at different temperatures are obtained by metal organic chemical vapor deposition (MOCVD). And the different variation behaviors of resistivity with growth condition for high- temperature(HT)-grown and low-temperature(LT)-grown p-GaN films are investigated. It is found that the resistivity of HT-grown p-GaN film is nearly unchanged when the NH3 flow rate or reactor pressure increases. However, it decreases largely for LT-grown p-GaN film. These different variations may be attributed to the fact that carbon impurities are easy to incorporate into p-GaN film when the growth temperature is low. It results in a relatively high carbon concentration in LT-grown p-GaN film compared with HT-grown one. Therefore, carbon concentration is more sensitive to the growth condition in these samples, ultimately, leading to the different variation behaviors of resistivity for HT- and LT-grown ones. Project supported by the National Natural Science Foundation of China (Grant Nos. 61474110, 61377020, 61376089, 61223005, and 61176126), the National Natural Science Fund for Distinguished Young Scholars, China (Grant No. 60925017), the One Hundred Person Project of the Chinese Academy of Sciences, and the Basic Research Project of Jiangsu Province, China (Grant No. BK20130362).

  1. Global temperatures, precession, and CO{sub 2}

    SciTech Connect

    Thomson, D.J.

    1995-12-31

    Despite much work, the effects of the increasing quantities of carbon dioxide and other so-called {open_quotes}greenhouse gases{close_quotes} on the earth`s climate remain controversial. I show that previous statistical analyses of the climate time series are flawed due to inappropriate assumptions about the timing of the seasons and that the seasonal cycle appears to be changing at an unprecedented rate as a result of greenhouse forcing. Writing the dominant component of the annual seasonal temperature cycle as A(t) cos(2{pi}t + {theta}(t)) where t time in years, and the phase, {theta}(t), describes the timing of the seasons, I show that: From the start of the instrumental series in 1659, up to about 1940, the phase of the Northern Hemisphere temperature {theta}(t) has a decreasing linear trend of about 50 arc-seconds per year. Since about 1940 the phase of the annual cycle has increased rapidly at an average rate of 300 arc-seconds per year with even more rapid changes at many individual stations. From these observations I conclude: (1) From 1669 to 1940 the temperature cycle usually follows perihelion rather the equinoxes. (2) The change after 1940 may be accounted for as a result in the increase in the direct radiation component of temperature by CO{sub 2} relative to transport. (3) The apparent seasonal dependence of the slope of the hemispheric temperature records over the last century noted by several researchers is an artifact of ignoring precession. (4) Changes in CO{sub 2} resulting from human activities are causing large, and readily observable, changes both in the average temperature and in the seasonal cycle.

  2. Variational principle and vibration properties of functionally graded circular plate with temperature changes

    NASA Astrophysics Data System (ADS)

    Fan, Tao; Zou, Guangping

    2011-11-01

    In this paper, the variational principle of functionally graded circular plate is presented by the variational integral method taking temperature change into account. The vibration governing equation is illustrated, which will be benefit for the numerical simulation with finite element method in further investigations. The numerical results show that the natural frequency increases as the graded coefficient increases in the chosen domain. It can be observed that the vibration characteristics are influenced by the temperature changes obviously. Moreover, the natural frequency is larger for thicker FGM circular plates, while it is lower for thinner ones. Furthermore, the first four vibration mode shapes with different thickness of FGM circular plate are illustrated.

  3. Variational principle and vibration properties of functionally graded circular plate with temperature changes

    NASA Astrophysics Data System (ADS)

    Fan, Tao; Zou, Guangping

    2012-04-01

    In this paper, the variational principle of functionally graded circular plate is presented by the variational integral method taking temperature change into account. The vibration governing equation is illustrated, which will be benefit for the numerical simulation with finite element method in further investigations. The numerical results show that the natural frequency increases as the graded coefficient increases in the chosen domain. It can be observed that the vibration characteristics are influenced by the temperature changes obviously. Moreover, the natural frequency is larger for thicker FGM circular plates, while it is lower for thinner ones. Furthermore, the first four vibration mode shapes with different thickness of FGM circular plate are illustrated.

  4. Variations of temperature of acrylic bone cements prepared by hand and vacuum mixing during their polymerization.

    PubMed

    Liptáková, Tatiana; Lelovics, Henrietta; Necas, Libor

    2009-01-01

    The aim of this work was to investigate variations of temperature in acrylic bone cement SmartSet HV during its polymerization as the function of mixing technique (hand mixing and vacuum mixing) and sample thickness. The temperature of 25-mm diameter samples differing in their thickness was monitored using a parallel plate measuring system of the compact rheometer preheated to the body temperature. The curves representing the temperature measured and average values of times needed to obtain the peak temperatures of the test samples prepared by different techniques of mixing are presented and discussed. It was found that the maximum temperature and also the times of peak temperatures rose with sample thickness but at different rate for each technique of mixing.

  5. Regional and local scale modeling of stream temperatures and spatio-temporal variation in thermal sensitivities.

    PubMed

    Hilderbrand, Robert H; Kashiwagi, Michael T; Prochaska, Anthony P

    2014-07-01

    Understanding variation in stream thermal regimes becomes increasingly important as the climate changes and aquatic biota approach their thermal limits. We used data from paired air and water temperature loggers to develop region-scale and stream-specific models of average daily water temperature and to explore thermal sensitivities, the slopes of air-water temperature regressions, of mostly forested streams across Maryland, USA. The region-scale stream temperature model explained nearly 90 % of the variation (root mean square error = 0.957 °C), with the mostly flat coastal plain streams having significantly higher thermal sensitivities than the steeper highlands streams with piedmont streams intermediate. Model R (2) for stream-specific models was positively related to a stream's thermal sensitivity. Both the regional and the stream-specific air-water temperature regression models benefited from including mean daily discharge from regional gaging stations, but the degree of improvement declined as a stream's thermal sensitivity increased. Although catchment size had no relationship to thermal sensitivity, steeper streams or those with greater amounts of forest in their upstream watershed were less thermally sensitive. The subset of streams with three or more summers of temperature data exhibited a wide range of annual variation in thermal sensitivity at a site, with the variation not attributable to discharge, precipitation patterns, or physical attributes of streams or their watersheds. Our findings are a useful starting point to better understand patterns in stream thermal regimes. However, a more spatially and temporally comprehensive monitoring network should increase understanding of stream temperature variation and its controls as climatic patterns change.

  6. Interannual variations of the discharge of Amu Darya and Syr Darya estimated from global atmospheric precipitation

    NASA Astrophysics Data System (ADS)

    Nezlin, Nikolay P.; Kostianoy, Andrey G.; Lebedev, Sergey A.

    2004-06-01

    The discharges of two main rivers of the basin of the Aral Sea (Amu Darya and Syr Darya) was estimated from two global data sets of monthly atmospheric precipitation (GPCP, collected in 1979-2001 and GPCC, collected in 1986-2001) integrated over the areas of formation of the discharge of these two rivers. Both seasonal and interannual variations of atmospheric precipitation are evident. A decreasing trend is evident in Amu Darya discharge; the discharge of Syr Darya did not decrease since 1985. Both trends well correspond to interannual variability of the sea level of two independent basins of the Aral Sea (the Large Sea and the Small Sea) derived from the TOPEX/Poseidon satellite altimetry (1992-2002).

  7. Global variation in CYP2C8–CYP2C9 functional haplotypes

    PubMed Central

    Speed, William C; Kang, Soonmo Peter; Tuck, David P; Harris, Lyndsay N; Kidd, Kenneth K

    2009-01-01

    We have studied the global frequency distributions of 10 single nucleotide polymorphisms (SNPs) across 132 kb of CYP2C8 and CYP2C9 in ∼2500 individuals representing 45 populations. Five of the SNPs were in noncoding sequences; the other five involved the more common missense variants (four in CYP2C8, one in CYP2C9) that change amino acids in the gene products. One haplotype containing two CYP2C8 coding variants and one CYP2C9 coding variant reaches an average frequency of 10% in Europe; a set of haplotypes with a different CYP2C8 coding variant reaches 17% in Africa. In both cases these haplotypes are found in other regions of the world at <1%. This considerable geographic variation in haplotype frequencies impacts the interpretation of CYP2C8/CYP2C9 association studies, and has pharmacogenomic implications for drug interactions. PMID:19381162

  8. Temperature-independent diel variation in soil respiration observed from a temperate deciduous forest

    SciTech Connect

    Post, Wilfred M; Liu, Qing; Edwards, Nelson T; Gu, Lianhong; Childs, Joanne; Lenhart, Suzanne M

    2006-01-01

    The response of soil respiration (Rs) to temperature depends largely on the temporal and spatial scales of interest and how other environmental factors interact with this response. They are often represented by empirical exponential equations in many ecosystem analyses because of the difficulties in separating covarying environmental responses and in observing below ground processes. The objective of this study was to quantify a soil temperature-independent component in Rs by examining the diel variation of an Rs time series measured in a temperate deciduous forest located at Oak Ridge, TN, USA between March and December 2003. By fitting 2 hourly, continuous automatic chamber measurements of CO2 efflux at the soil surface to a Q10 function to obtain the temperature-dependent respiration (Rt) and plotting the diel cycles of Rt, Rs, and their difference (Ri), we found that an obvious temperature-independent component exists in Rs during the growing season. The diel cycle of this component has a distinct day/night pattern and agrees well with diel variations in photosynthetically active radiation (PAR) and air temperature. Elevated canopy CO2 concentration resulted in similar patterns in the diel cycle of the temperature-independent component but with different daily average rates in different stages of growing season. We speculate that photosynthesis of the stand is one of the main contributors to this temperature-independent respiration component although more experiments are needed to draw a firm conclusion. We also found that despite its relatively small magnitude compared with the temperature-dependent component, the diel variation in the temperature-independent component can lead to significantly different estimates of the temperature sensitivity of soil respiration in the study forest. As a result, the common practice of using fitted temperature-dependent function from night-time measurements to extrapolate soil respiration during the daytime may underestimate

  9. Prediction of seasonal climate-induced variations in global food production

    NASA Astrophysics Data System (ADS)

    Iizumi, Toshichika; Sakuma, Hirofumi; Yokozawa, Masayuki; Luo, Jing-Jia; Challinor, Andrew J.; Brown, Molly E.; Sakurai, Gen; Yamagata, Toshio

    2013-10-01

    Consumers, including the poor in many countries, are increasingly dependent on food imports and are thus exposed to variations in yields, production and export prices in the major food-producing regions of the world. National governments and commercial entities are therefore paying increased attention to the cropping forecasts of important food-exporting countries as well as to their own domestic food production. Given the increased volatility of food markets and the rising incidence of climatic extremes affecting food production, food price spikes may increase in prevalence in future years. Here we present a global assessment of the reliability of crop failure hindcasts for major crops at two lead times derived by linking ensemble seasonal climatic forecasts with statistical crop models. We found that moderate-to-marked yield loss over a substantial percentage (26-33%) of the harvested area of these crops is reliably predictable if climatic forecasts are near perfect. However, only rice and wheat production are reliably predictable at three months before the harvest using within-season hindcasts. The reliabilities of estimates varied substantially by crop--rice and wheat yields were the most predictable, followed by soybean and maize. The reasons for variation in the reliability of the estimates included the differences in crop sensitivity to the climate and the technology used by the crop-producing regions. Our findings reveal that the use of seasonal climatic forecasts to predict crop failures will be useful for monitoring global food production and will encourage the adaptation of food systems toclimatic extremes.

  10. Radiative analysis of global mean temperature trends in the middle atmosphere: Effects of non-locality and secondary absorption bands

    NASA Astrophysics Data System (ADS)

    Fomichev, V. I.; Jonsson, A. I.; Ward, W. E.

    2016-02-01

    In this paper, we provide a refined and extended assignment of past and future temperature changes relative to previous analyses and describe and evaluate the relevance of vertical coupling and non-linear and secondary radiative mechanisms for the interpretation of climatic temperature variations in the middle atmosphere. Because of their nature, the latter mechanisms are not adequately accounted for in most regression analyses of temperature trends as a function of local constituent variations. These mechanisms are examined using (1) globally averaged profiles from transient simulations with the Canadian Middle Atmosphere Model (CMAM) forced by changes in greenhouse gases and ozone depleting substances and (2) a one-dimensional radiative-equilibrium model forced using the diagnosed global mean changes in radiatively active constituents as derived from the CMAM model runs. The conditions during the periods 1975 to 1995 and 2010 to 2040 (during which the rates of change in ozone and CO2 differ) provide a suitable contrast for the role of the non-linear and non-local mechanisms being evaluated in this paper to be clearly differentiated and evaluated. Vertical coupling of radiative transfer effects and the influence of secondary absorption bands are important enough to render the results of multiple linear regression analyses between the temperature response and constituent changes misleading. These effects are evaluated in detail using the 1D radiative-equilibrium model using profiles from the CMAM runs as inputs. In order to explain the differences in the CMAM temperature trends prior to and after 2000 these other radiative effects must be considered in addition to local changes in the radiatively active species. The middle atmosphere temperature cools in response to CO2 and water vapor increases, but past and future trends are modulated by ozone changes.

  11. Seasonal Variations of Temperature, Acetylene and Ethane in Saturn's Stratosphere from 2005 to 2010

    NASA Astrophysics Data System (ADS)

    Sinclair, James; Irwin, P. G. J.; Fletcher, L. N.; Moses, J. I.; Greathouse, T. K.; Friedson, A. J.; Hesman, B.; Hurley, J.; Merlet, C.

    2012-10-01

    Acetylene (C2H2) and ethane (C2H6) exemplify by-products of complex photochemistry in Saturn’s stratosphere. Their relative stability together with their strong vertical gradients in concentration allow for their use as tracers of vertical motion in Saturn’s lower stratosphere. Earlier studies of Saturn's hydrocarbons have provided only a snapshot of their behaviour with temporal variations remaining to be determined. In this study, we investigate how the thermal structure and concentrations of acetylene and ethane have evolved on Saturn with the changing season. We use FIRMAP (15.5 cm-1 spectral resolution) Cassini-CIRS observations, initially retrieve temperature and subsequently retrieve the abundances of acetylene and ethane. In comparing 2005, 2009 and 2010 results, we observe the disappearance of Saturn's southern warm polar hood with cooling of up to 18.6 K ± 0.9 K at 1.1 mbar south of 75°S (planetographic). This suggests dissipation of Saturn's south polar vortex in addition to an autumnal cooling. We observe a 20% ± 9% enrichment of acetylene and a 30% ± 10% enrichment of ethane at 2.1 mbar at 25°N, together with a 14% ± 9% depletion of acetylene and an 18% ± 7% depletion of ethane at the same altitude at 15°S. This suggests the presence of localised downwelling and upwelling at these latitudes, respectively. These vertical motions are consistent with a recently-developed GCM (global circulation model) of Saturn's tropopause and stratosphere, which predicts this pattern of upwelling and downwelling as a result of seasonally-reversing Hadley circulation.

  12. Intra-population level variation in thresholds for physical dormancy-breaking temperature

    PubMed Central

    Liyanage, Ganesha S.; Ooi, Mark K. J.

    2015-01-01

    Background and Aims Intra-population variation in seed dormancy is an advantage for population persistence in unpredictable environments. The important role played by physically dormant species in these habitats makes understanding the level of variation in their dormancy a key ecological question. Heat produced in the soil is the major dormancy-breaking stimulus and, in fire prone ecosystems, soil temperatures generated by fire may vary spatially and over time. While many studies have investigated variation in initial dormancy, a measure that is of little value in fire-prone ecosystems, where initial dormancy levels are uniformly high, intra-population variation in dormancy-breaking temperature thresholds has never been quantified. This study predicted that species would display variation in dormancy-breaking temperature thresholds within populations, and investigated whether this variation occurred between individual plants from the same maternal environment. Methods The intra-population variation in dormancy-breaking thresholds of five common physically dormant shrub species (family Fabaceae) from fire-prone vegetation in south-eastern Australia was assessed using heat treatments and germination trials. Replicate batches of seeds from each of four maternal plants of Dillwynia floribunda, Viminaria juncea, Bossiaea heterophylla, Aotus ericoides and Acacia linifolia were treated at 40, 60, 80, 100 and 120 °C. Key Results Dormancy-breaking response to heat treatments varied significantly among individual plants for all species, with some individuals able to germinate after heating at low temperatures and others restricting germination to temperatures that only occur as a result of high-severity fires. Germination rate (T50) varied among individuals of three species. Conclusions Variation detected among individuals that were in close proximity to each other indicates that strong differences in dormancy-breaking temperature thresholds occur throughout the broader

  13. Reconstructions of global near-surface temperature change since the mid 19th century

    NASA Astrophysics Data System (ADS)

    Morice, Colin; Rayner, Nick; Kennedy, John

    2016-04-01

    Incomplete and non-uniform global observational coverage is a prominent source of uncertainty in instrumental records of global near-surface temperature change. In this study statistical methods are applied to the HadCRUT4 near-surface temperature data set to obtain improved estimates of global near-surface temperature change since the mid 19th century. Methods applied include those that interpolate according to local correlation structure (kriging) and reduced space methods that learn large-scale temperature patterns. The performance of each statistical reconstruction method 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. In application to HadCRUT4 data the statistical reconstructions 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). There is broad agreement between estimates of global and hemispheric changes throughout much of the 20th and 21st century. Agreement is reduced in data sparse periods and regions, notably in the 19th century and in the southern hemisphere. This finding is supported by the results of the climate model based benchmarks and highlights 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 set.

  14. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    NASA Astrophysics Data System (ADS)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  15. Pliocene three-dimensional global ocean temperature reconstruction

    USGS Publications Warehouse

    Dowsett, H.J.; Robinson, M.M.; Foley, K.M.

    2009-01-01

    The thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water temperature estimates from 27 locations produced using Mg/Ca paleothermometry based upon the ostracod genus Krithe. Deep water temperature estimates are skewed toward the Atlantic Basin (63% of the locations) and represent depths from 1000m to 4500 m. This reconstruction, meant to serve as a validation data set as well as an initialization for coupled numerical climate models, assumes a Pliocene water mass framework similar to that which exists today, with several important modifications. The area of formation of present day North Atlantic Deep Water (NADW) was expanded and extended further north toward the Arctic Ocean during the mid-Piacenzian relative to today. This, combined with a deeper Greenland-Scotland Ridge, allowed a greater volume of warmer NADW to enter the Atlantic Ocean. In the Southern Ocean, the Polar Front Zone was expanded relative to present day, but shifted closer to the Antarctic continent. This, combined with at least seasonal reduction in sea ice extent, resulted in decreased Antarctic Bottom Water (AABW) production (relative to present day) as well as possible changes in the depth of intermediate waters. The reconstructed mid-Piacenzian three-dimensional ocean was warmer overall than today, and the hypothesized aerial extent of water masses appears to fit the limited stable isotopic data available for this time period. ?? Author(s) 2009.

  16. Pliocene three-dimensional global ocean temperature reconstruction

    NASA Astrophysics Data System (ADS)

    Dowsett, H. J.; Robinson, M. M.; Foley, K. M.

    2009-12-01

    The thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water temperature estimates from 27 locations produced using Mg/Ca paleothermometry based upon the ostracod genus Krithe. Deep water temperature estimates are skewed toward the Atlantic Basin (63% of the locations) and represent depths from 1000 m to 4500 m. This reconstruction, meant to serve as a validation data set as well as an initialization for coupled numerical climate models, assumes a Pliocene water mass framework similar to that which exists today, with several important modifications. The area of formation of present day North Atlantic Deep Water (NADW) was expanded and extended further north toward the Arctic Ocean during the mid-Piacenzian relative to today. This, combined with a deeper Greenland-Scotland Ridge, allowed a greater volume of warmer NADW to enter the Atlantic Ocean. In the Southern Ocean, the Polar Front Zone was expanded relative to present day, but shifted closer to the Antarctic continent. This, combined with at least seasonal reduction in sea ice extent, resulted in decreased Antarctic Bottom Water (AABW) production (relative to present day) as well as possible changes in the depth of intermediate waters. The reconstructed mid-Piacenzian three-dimensional ocean was warmer overall than today, and the hypothesized aerial extent of water masses appears to fit the limited stable isotopic data available for this time period.

  17. The Effects of Heat Treatment and Microstructure Variations on Disk Superalloy Properties at High Temperature

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Telesman, Jack; Garg, Anita

    2008-01-01

    The effects of heat treatment and resulting microstructure variations on high temperature mechanical properties were assessed for a powder metallurgy disk superalloy LSHR. Blanks were consistently supersolvus solution heat treated and quenched at two cooling rates, than aged at varying temperatures and times. Tensile, creep, and dwell fatigue crack growth tests were then performed at 704 C. Gamma' precipitate microstructures were quantified. Relationships between heat treatment-microstructure, heat treatment-mechanical properties, and microstructure-mechanical properties were assessed.

  18. PlasmoView: a web-based resource to visualise global Plasmodium falciparum genomic variation.

    PubMed

    Preston, Mark D; Assefa, Samuel A; Ocholla, Harold; Sutherland, Colin J; Borrmann, Steffen; Nzila, Alexis; Michon, Pascal; Hien, Tran Tinh; Bousema, Teun; Drakeley, Christopher J; Zongo, Issaka; Ouédraogo, Jean-Bosco; Djimde, Abdoulaye A; Doumbo, Ogobara K; Nosten, Francois; Fairhurst, Rick M; Conway, David J; Roper, Cally; Clark, Taane G

    2014-06-01

    Malaria is a global public health challenge, with drug resistance a major barrier to disease control and elimination. To meet the urgent need for better treatments and vaccines, a deeper knowledge of Plasmodium biology and malaria epidemiology is required. An improved understanding of the genomic variation of malaria parasites, especially the most virulent Plasmodium falciparum (Pf) species, has the potential to yield new insights in these areas. High-throughput sequencing and genotyping is generating large amounts of genomic data across multiple parasite populations. The resulting ability to identify informative variants, particularly single-nucleotide polymorphisms (SNPs), will lead to the discovery of intra- and inter-population differences and thus enable the development of genetic barcodes for diagnostic assays and clinical studies. Knowledge of genetic variability underlying drug resistance and other differential phenotypes will also facilitate the identification of novel mutations and contribute to surveillance and stratified medicine applications. The PlasmoView interactive web-browsing tool enables the research community to visualise genomic variation and annotation (eg, biological function) in a geographic setting. The first release contains over 600,000 high-quality SNPs in 631 Pf isolates from laboratory strains and four malaria-endemic regions (West Africa, East Africa, Southeast Asia and Oceania). PMID:24338354

  19. PlasmoView: A Web-based Resource to Visualise Global Plasmodium falciparum Genomic Variation

    PubMed Central

    Preston, Mark D.; Assefa, Samuel A.; Ocholla, Harold; Sutherland, Colin J.; Borrmann, Steffen; Nzila, Alexis; Michon, Pascal; Hien, Tran Tinh; Bousema, Teun; Drakeley, Christopher J.; Zongo, Issaka; Ouédraogo, Jean-Bosco; Djimde, Abdoulaye A.; Doumbo, Ogobara K.; Nosten, Francois; Fairhurst, Rick M.; Conway, David J.; Roper, Cally; Clark, Taane G.

    2014-01-01

    Malaria is a global public health challenge, with drug resistance a major barrier to disease control and elimination. To meet the urgent need for better treatments and vaccines, a deeper knowledge of Plasmodium biology and malaria epidemiology is required. An improved understanding of the genomic variation of malaria parasites, especially the most virulent Plasmodium falciparum (Pf) species, has the potential to yield new insights in these areas. High-throughput sequencing and genotyping is generating large amounts of genomic data across multiple parasite populations. The resulting ability to identify informative variants, particularly single-nucleotide polymorphisms (SNPs), will lead to the discovery of intra- and inter-population differences and thus enable the development of genetic barcodes for diagnostic assays and clinical studies. Knowledge of genetic variability underlying drug resistance and other differential phenotypes will also facilitate the identification of novel mutations and contribute to surveillance and stratified medicine applications. The PlasmoView interactive web-browsing tool enables the research community to visualise genomic variation and annotation (eg, biological function) in a geographic setting. The first release contains over 600 000 high-quality SNPs in 631 Pf isolates from laboratory strains and four malaria-endemic regions (West Africa, East Africa, Southeast Asia and Oceania). PMID:24338354

  20. Do differences in Toxoplasma prevalence influence global variation in secondary sex ratio? Preliminary ecological regression study.

    PubMed

    Dama, Madhukar S; Martinec Nováková, Lenka; Flegr, Jaroslav

    2016-08-01

    Sex of the fetus is genetically determined such that an equal number of sons and daughters are born in large populations. However, the ratio of female to male births across human populations varies significantly. Many factors have been implicated in this. The theory that natural selection should favour female offspring under suboptimal environmental conditions implies that pathogens may affect secondary sex ratio (ratio of male to female births). Using regression models containing 13 potential confounding factors, we have found that variation of the secondary sex ratio can be predicted by seroprevalence of Toxoplasma across 94 populations distributed across African, American, Asian and European continents. Toxoplasma seroprevalence was the third strongest predictor of secondary sex ratio, β = -0·097, P < 0·01, after son preference, β = 0·261, P < 0·05, and fertility, β = -0·145, P < 0·001. Our preliminary results suggest that Toxoplasma gondii infection could be one of the most important environmental factors influencing the global variation of offspring sex ratio in humans. The effect of latent toxoplasmosis on public health could be much more serious than it is usually supposed to be. PMID:27350331

  1. Color Photometry of the Small Saturnian Satellites: Global and Regional Variations on Prometheus and Calypso

    NASA Astrophysics Data System (ADS)

    Morrison, Sarah J.; Helfenstein, P.; Thomas, P. C.; Veverka, J.

    2010-10-01

    We investigate color variations of Prometheus and Calypso using recent high resolution calibrated Cassini Imaging Subsystem (ISS) images with the Narrow Angle Camera (NAC) broadband filters UV3 (338 nm) , GRN (568 nm), and IR3 (930 nm) in comparison to those of Pandora, Janus, Epimetheus, and Telesto examined previously (Morrison et al., 2009, DPS 45.04). The average UV3/IR3 ratio values are as follows: Prometheus- 0.47, Pandora- 0.53, Janus- 0.57, Epimetheus- 0.58, Telesto- 0.95, and Calypso- 0.77 with formal uncertainties < 0.01 due to noise. While both Prometheus and Calypso continue the trend of increasing blueness toward the E-ring, Calypso differs in color from Telesto with a lower UV3/IR3 ratio and a mean UV3/GRN ratio value of 0.7 compared to Telesto's mean UV3/GRN value of 0.9 despite both being Trojans of Tethys. Calypso's surface also exhibits wider color and albedo variations than on Telesto and distinct UV3-bright units undergoing downslope transport with UV3/IR3 ratio values of 0.05 greater than the mean. Calypso's mean global CLR (611 nm) albedo at normal incidence and 35° phase is 13% higher than Telesto's, but its albedo range is broader and overlaps Telesto's. The color differences between these two moons may reflect varying degrees of surface burial and contamination from ring particles.

  2. Variational contrast enhancement guided by global and local contrast measurements for single-image defogging

    NASA Astrophysics Data System (ADS)

    Zhou, Li; Bi, Du-Yan; He, Lin-Yuan

    2015-01-01

    The visibility of images captured in foggy conditions is impaired severely by a decrease in the contrasts of objects and veiling with a characteristic gray hue, which may limit the performance of visual applications out of doors. Contrast enhancement together with color restoration is a challenging mission for conventional fog-removal methods, as the degrading effect of fog is largely dependent on scene depth information. Nowadays, people change their minds by establishing a variational framework for contrast enhancement based on a physically based analytical model, unexpectedly resulting in color distortion, dark-patch distortion, or fuzzy features of local regions. Unlike previous work, our method treats an atmospheric veil as a scattering disturbance and formulates a foggy image as an energy functional minimization to estimate direct attenuation, originating from the work of image denoising. In addition to a global contrast measurement based on a total variation norm, an additional local measurement is designed in that optimal problem for the purpose of digging out more local details as well as suppressing dark-patch distortion. Moreover, we estimate the airlight precisely by maximization with a geometric constraint and a natural image prior in order to protect the faithfulness of the scene color. With the estimated direct attenuation and airlight, the fog-free image can be restored. Finally, our method is tested on several benchmark and realistic images evaluated by two assessment approaches. The experimental results imply that our proposed method works well compared with the state-of-the-art defogging methods.

  3. Climate change, global warming and coral reefs: modelling the effects of temperature.

    PubMed

    Crabbe, M James C

    2008-10-01

    Climate change and global warming have severe consequences for the survival of scleractinian (reef-building) corals and their associated ecosystems. This review summarizes recent literature on the influence of temperature on coral growth, coral bleaching, and modelling the effects of high temperature on corals. Satellite-based sea surface temperature (SST) and coral bleaching information available on the internet is an important tool in monitoring and modelling coral responses to temperature. Within the narrow temperature range for coral growth, corals can respond to rate of temperature change as well as to temperature per se. We need to continue to develop models of how non-steady-state processes such as global warming and climate change will affect coral reefs.

  4. Paleosecular Variation and Time-Averaged Field Behavior: Global and Regional Signatures

    NASA Astrophysics Data System (ADS)

    Johnson, C. L.; Cromwell, G.; Tauxe, L.; Constable, C.

    2012-12-01

    We use an updated global dataset of directional and intensity data from lava flows to investigate time-averaged field (TAF) and paleosecular variation (PSV) signatures regionally and globally. The data set includes observations from the past 10 Ma, but we focus our investigations on the field structure over past 5 Ma, in particular during the Brunhes and Matuyama. We restrict our analyses to sites with at least 5 samples (all of which have been stepwise demagnetized), and for which the estimate of the Fisher precision parameter, k, is at least 50. The data set comprises 1572 sites from the past 5 Ma that span latitudes 78oS to 71oN; of these ˜40% are from the Brunhes chron and ˜20% are from the Matuyama chron. Age control at the site level is variable because radiometric dates are available for only about one third of our sites. New TAF models for the Brunhes show longitudinal structure. In particular, high latitude flux lobes are observed, constrained by improved data sets from N. and S. America, Japan, and New Zealand. We use resampling techniques to examine possible biases in the TAF and PSV incurred by uneven temporal sampling, and the limited age information available for many sites. Results from Hawaii indicate that resampling of the paleodirectional data onto a uniform temporal distribution, incorporating site ages and age errors leads to a TAF estimate for the Brunhes that is close to that reported for the actual data set, but a PSV estimate (virtual geomagnetic pole dispersion) that is increased relative to that obtained from the unevenly sampled data. The global distribution of sites in our dataset allows us to investigate possible hemispheric asymmetries in field structure, in particular differences between north and south high latitude field behavior and low latitude differences between the Pacific and Atlantic hemispheres.

  5. A quantitative assessment of the relationship between precipitation deficits and air temperature variations

    NASA Astrophysics Data System (ADS)

    He, B.; Wang, H. L.; Wang, Q. F.; Di, Z. H.

    2015-06-01

    Previous studies have reported precipitation deficits related to temperature extremes. However, how and to what extent precipitation deficits affect surface air temperatures is still poorly understood. In this study, the relationship between precipitation deficits and surface temperatures was examined in China from 1960 to 2012 based on monthly temperature and precipitation records from 565 stations. Significant negative correlations were identified in each season, with the strongest relationships in the summer, indicating that higher temperatures usually accompanied water-deficient conditions and lower temperatures usually accompanied wet conditions. The examination of the correlations based on 30 year moving windows suggested that the interaction between the two variables has declined over the past three decades. Further investigation indicated a higher impact of extreme dry conditions on temperature than that of extreme wet conditions. In addition, a new simple index (Dry Temperature Index, DTI) was developed and used to quantitatively describe the relationship between water deficits and air temperature variations. We tested and compared the DTI in the coldest month (January) and the hottest month (July) of the year, station by station. In both months, the number of stations with a DThighI ≥ 50% was greater than those with a DThighI < 50%, indicating that a greater proportion of higher temperatures occurred during dry conditions. Based on the results, we conclude that water deficits in China are usually correlated to high temperatures but not to low temperatures.

  6. Diurnal Temperature Variations Affect Development of a Herbivorous Arthropod Pest and its Predators

    PubMed Central

    Vangansbeke, Dominiek; Audenaert, Joachim; Nguyen, Duc Tung; Verhoeven, Ruth; Gobin, Bruno; Tirry, Luc; De Clercq, Patrick

    2015-01-01

    The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen’s inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen’s inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes. PMID:25874697

  7. Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators.

    PubMed

    Vangansbeke, Dominiek; Audenaert, Joachim; Nguyen, Duc Tung; Verhoeven, Ruth; Gobin, Bruno; Tirry, Luc; De Clercq, Patrick

    2015-01-01

    The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen's inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes. PMID:25874697

  8. Temperature variation in metal ceramic technology analyzed using time domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sinescu, Cosmin; Topala, Florin I.; Negrutiu, Meda Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.

    2014-01-01

    The quality of dental prostheses is essential in providing good quality medical services. The metal ceramic technology applied in dentistry implies ceramic sintering inside the dental oven. Every ceramic material requires a special sintering chart which is recommended by the producer. For a regular dental technician it is very difficult to evaluate if the temperature inside the oven remains the same as it is programmed on the sintering chart. Also, maintaining the calibration in time is an issue for the practitioners. Metal ceramic crowns develop a very accurate pattern for the ceramic layers depending on the temperature variation inside the oven where they are processed. Different patterns were identified in the present study for the samples processed with a variation in temperature of +30 °C to +50 °C, respectively - 30 0°C to -50 °C. The OCT imagistic evaluations performed for the normal samples present a uniform spread of the ceramic granulation inside the ceramic materials. For the samples sintered at a higher temperature an alternation between white and darker areas between the enamel and opaque layers appear. For the samples sintered at a lower temperature a decrease in the ceramic granulation from the enamel towards the opaque layer is concluded. The TD-OCT methods can therefore be used efficiently for the detection of the temperature variation due to the ceramic sintering inside the ceramic oven.

  9. Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations

    NASA Astrophysics Data System (ADS)

    Shinbori, A.; Hori, T.; Tanaka, Y.; Koyama, Y.; Kikuchi, T.; Nagatsuma, T.

    2013-12-01

    In order to investigate temporary and spatial evolutions of global geomagnetic field variations from high-latitude to the geomagnetic equator during geomagnetic storms, we analyzed 1-min geomagnetic field data, which are obtained from the CARISMA, GIMA, IMAGE, MACCS, and NSWM networks, and provided by WDC geomagnetism in Kyoto University. During the main phase of geomagnetic storms, the daytime ionospheric equivalent currents showed that two-cell type of ionospheric currents driven by the enhanced region-1 field-aligned currents (R1 FACs) are intensified significantly and expanded to the low-latitude region of ~30 degrees (GMLAT). The centers of the two-cell type of ionospheric currents were located around 70 and 65 degrees in the morning and afternoon, respectively. Corresponding to the intensification of the R1 FACs, an enhancement of the eastward/westward equatorial electrojet occurred at the daytime/nighttime dip equator. This signature suggests that the enhanced convection electric field penetrates to both the daytime and nighttime equator. During the recovery phase, the daytime equivalent current showed that the two new pairs of twin-vortices, which are different from two-cell type of ionospheric currents driven by the R1 FACs, appear in the polar cap and middle latitude. The former led to the enhanced NBZ FACs driven by the lobe reconnection tailward of the cusps due to the northward IMF, while the latter was generated by the enhanced R2 FACs. Associated with these magnetic field variations in the middle latitudes and polar cap, the equatorial magnetic field variation showed a strongly negative signature produced by the westward equatorial electrojet current due to the dusk-to-dawn electric field.

  10. The Effects of Temperature Variation on the Sensitivity to Pesticides: a Study on the Slime Mould Dictyostelium discoideum (Protozoa).

    PubMed

    Amaroli, Andrea

    2015-07-01

    Slime moulds live in agricultural ecosystems, where they play an important role in the soil fertilization and in the battle against crop pathogens. In an agricultural soil, the amoebae are exposed to different stress factors such as pesticides and weather conditions. The use of pesticides increased up from 0.49 kg per hectare in 1961 to 2 kg in 2004, and the global greenhouse gas emission has grown 70% between 1970 and 2004 leading to a global fluctuation of average surface temperature. Therefore, the European Directive 2009/128/EC has led to a new approach to agriculture, with the transition from an old concept based on high use of pesticides and fossil fuels to an agriculture aware of biodiversity and health issues. We studied the effects of temperature variations and pesticides on Dictyostelium discoideum. We measured the fission rate, the ability to differentiate and the markers of stress such as the activity and presence of pseudocholinesterase and the presence of heat shock protein 70. Our results highlight how the sensitivity to zinc, aluminium, silver, copper, cadmium, mercury, diazinon and dicofol changes for a 2 °C variation from nothing/low to critical. Our work suggests considering, in future regulations, about the use of pesticides as their toxic effect on non-target organisms is strongly influenced by climate temperatures. In addition, there is a need for a new consideration of the protozoa, which takes into account recent researches about the presence in this microorganism of classical neurotransmitters that, similar to those in animals, make protozoa an innocent target of neurotoxic pesticides in the battle against the pest crops.

  11. The Effects of Temperature Variation on the Sensitivity to Pesticides: a Study on the Slime Mould Dictyostelium discoideum (Protozoa).

    PubMed

    Amaroli, Andrea

    2015-07-01

    Slime moulds live in agricultural ecosystems, where they play an important role in the soil fertilization and in the battle against crop pathogens. In an agricultural soil, the amoebae are exposed to different stress factors such as pesticides and weather conditions. The use of pesticides increased up from 0.49 kg per hectare in 1961 to 2 kg in 2004, and the global greenhouse gas emission has grown 70% between 1970 and 2004 leading to a global fluctuation of average surface temperature. Therefore, the European Directive 2009/128/EC has led to a new approach to agriculture, with the transition from an old concept based on high use of pesticides and fossil fuels to an agriculture aware of biodiversity and health issues. We studied the effects of temperature variations and pesticides on Dictyostelium discoideum. We measured the fission rate, the ability to differentiate and the markers of stress such as the activity and presence of pseudocholinesterase and the presence of heat shock protein 70. Our results highlight how the sensitivity to zinc, aluminium, silver, copper, cadmium, mercury, diazinon and dicofol changes for a 2 °C variation from nothing/low to critical. Our work suggests considering, in future regulations, about the use of pesticides as their toxic effect on non-target organisms is strongly influenced by climate temperatures. In addition, there is a need for a new consideration of the protozoa, which takes into account recent researches about the presence in this microorganism of classical neurotransmitters that, similar to those in animals, make protozoa an innocent target of neurotoxic pesticides in the battle against the pest crops. PMID:25515424

  12. Latitudinal variation in sensitivity of flower bud formation to high temperature in Japanese Taraxacum officinale.

    PubMed

    Yoshie, Fumio

    2014-05-01

    Control of flowering time plays a key role in the successful range expansion of plants. Taraxacum officinale has expanded throughout Japan during the 110 years after it was introduced into a cool temperate region. The present study tested a hypothesis that there is a genetic difference in the bud formation time in relation to temperature along latitudinal gradient of T. officinale populations. In Experiment 1, plants from three populations at different latitudes (26, 36, and 43°N) were grown at three temperatures. Time to flower bud appearance did not significantly differ among the three populations when plants were grown at 14 °C, whereas it increased with increasing latitude when grown at 19 and 24 °C. Rosette diameter was not different among the populations, indicating that the variation in bud formation time reflected a difference in genetic control rather than size variation. The latitudinal variation in bud appearance time was confirmed by Experiment 2 in which plants from 17 population were used. In Experiment 3, the size of plants that exhibited late-flowering was studied to test a hypothesis that the variation in flowering time reflects dormancy of vegetative growth, but the late-flowering plants were found to continue growth, indicating that vegetative dormancy was not the cause of the variation. The results clearly indicate that the degree of suppression of flower bud formation at high temperature decreases with latitude from north to south, which is under genetic control.

  13. Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

    1939-01-01

    Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

  14. Breeding phenology in Rana temporaria. Local variation is due to pond temperature and population size.

    PubMed

    Loman, Jon

    2016-09-01

    Frog breeding phenology in temperate zones is usually compared to progress of spring temperatures at a regional scale. However, local populations may differ substantially in phenology. To understand this, local climate and other aspects must be studied. In this study, breeding phenology of the common frog, Rana temporaria, in a set of ponds in southern Sweden is analyzed. There was within year a variation of up to 3 weeks in start of breeding among local populations. Water temperature was measured in the ponds, and breeding tended to be earlier in warmer ponds (surprise!). Breeding was also earlier in ponds with a large breeding congregation. Alternative reasons for these patterns are suggested and discussed. There was a large residual variation. The common frog has a wide range of acceptable wintering sites, and I hypothesize that the particular choice by a local population may explain part of this residual variation. PMID:27648237

  15. Global monthly sea surface nitrate fields estimated from remotely sensed sea surface temperature, chlorophyll, and modeled mixed layer depth

    NASA Astrophysics Data System (ADS)

    Arteaga, Lionel; Pahlow, Markus; Oschlies, Andreas

    2015-02-01

    Information about oceanic nitrate is crucial for making inferences about marine biological production and the efficiency of the biological carbon pump. While there are no optical properties that allow direct estimation of inorganic nitrogen, its correlation with other biogeochemical variables may permit its inference from satellite data. Here we report a new method for estimating monthly mean surface nitrate concentrations employing local multiple linear regressions on a global 1° by 1° resolution grid, using satellite-derived sea surface temperature, chlorophyll, and modeled mixed layer depth. Our method is able to reproduce the interannual variability of independent in situ nitrate observations at the Bermuda Atlantic Time Series, the Hawaii Ocean Time series, the California coast, and the southern New Zealand region. Our new method is shown to be more accurate than previous algorithms and thus can provide improved information on temporal and spatial nutrient variations beyond the climatological mean at regional and global scales.

  16. Evidence of local adaptation in the demographic response of American ginseng to interannual temperature variation.

    PubMed

    Souther, Sara; McGraw, James B

    2011-10-01

    Bioclimatic envelope models of species' responses to climate change are used to predict how species will respond to increasing temperatures. These models are frequently based on the assumption that the northern and southern boundaries of a species' range define its thermal niche. However, this assumption may be violated if populations are adapted to local temperature regimes and have evolved population-specific thermal optima. Considering the prevalence of local adaptation, the assumption of a species-wide thermal optimum may be violated for many species. We used spatially and temporally extensive demographic data for American ginseng (Panax quinquefolius L.) to examine range-wide variation in response of population growth rate (λ) to climatic factors. Our results suggest adaptation to local temperature, but not precipitation. For each population, λ was maximized when annual temperatures were similar to site-specific, long-term mean temperatures. Populations from disparate climatic zones responded differently to temperature variation, and there was a linear relation between population-level thermal optima and the 30-year mean temperature at each site. For species that are locally adapted to temperature, bioclimatic envelope models may underestimate the extent to which increasing temperatures will decrease population growth rate. Because any directional change from long-term mean temperatures will decrease population growth rates, all populations throughout a species' range will be adversely affected by temperature increase, not just populations at southern and low-elevation boundaries. Additionally, when a species' local thermal niche is narrower than its range-wide thermal niche, a smaller temperature increase than would be predicted by bioclimatic envelope approaches may be sufficient to decrease population growth.

  17. Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop.

    PubMed

    Zaka, Serge; Frak, Ela; Julier, Bernadette; Gastal, François; Louarn, Gaëtan

    2016-01-01

    Interest in the thermal acclimation of photosynthesis has been stimulated by the increasing relevance of climate change. However, little is known about intra-specific variations in thermal acclimation and its potential for breeding. In this article, we examined the difference in thermal acclimation between alfalfa (Medicago sativa) cultivars originating from contrasting origins, and sought to analyze the mechanisms in play. A series of experiments was carried out at seven growth temperatures between 5 and 35 °C using four cultivars from temperate and Mediterranean origin. Leaf traits, the photosynthetic rate at 25 °C (A400 (25)), the photosynthetic rate at optimal temperature (A400 (opt)), the thermal optimum of photosynthesis (Topt), and the photosynthetic parameters from the Farqhuar model were determined. Irrespective of cultivar origin, a clear shift in the temperature responses of photosynthesis was observed as a function of growth temperature, affecting thermal optimum of photosynthesis, photosynthetic rate at optimal temperature and photosynthetic rate at 25 °C. For both cultivars, Topt values increased linearly in leaves grown between 5 and 35 °C. Relative homeostasis of A400 (25) and A400 (opt) was found between 10 °C and 30 °C growth temperatures, but sharp declines were recorded at 5 and 35 °C. This homeostasis was achieved in part through modifications to leaf nitrogen content, which increased at extreme temperatures. Significant changes were also recorded regarding nitrogen partitioning in the photosynthetic apparatus and in the temperature dependence of photosynthetic parameters. The cultivars differed only in terms of the temperature response of photosynthetic parameters, with Mediterranean genotypes displaying a greater sensitivity of the maximum rate of Rubisco carboxylation to elevated temperatures. It was concluded that intra-specific variations in the temperature acclimation of photosynthesis exist among alfalfa cultivars

  18. Intraspecific variation in thermal acclimation of photosynthesis across a range of temperatures in a perennial crop

    PubMed Central

    Zaka, Serge; Frak, Ela; Julier, Bernadette; Gastal, François; Louarn, Gaëtan

    2016-01-01

    Interest in the thermal acclimation of photosynthesis has been stimulated by the increasing relevance of climate change. However, little is known about intra-specific variations in thermal acclimation and its potential for breeding. In this article, we examined the difference in thermal acclimation between alfalfa (Medicago sativa) cultivars originating from contrasting origins, and sought to analyze the mechanisms in play. A series of experiments was carried out at seven growth temperatures between 5 and 35 °C using four cultivars from temperate and Mediterranean origin. Leaf traits, the photosynthetic rate at 25 °C (A40025), the photosynthetic rate at optimal temperature (A400opt), the thermal optimum of photosynthesis (Topt), and the photosynthetic parameters from the Farqhuar model were determined. Irrespective of cultivar origin, a clear shift in the temperature responses of photosynthesis was observed as a function of growth temperature, affecting thermal optimum of photosynthesis, photosynthetic rate at optimal temperature and photosynthetic rate at 25 °C. For both cultivars, Topt values increased linearly in leaves grown between 5 and 35 °C. Relative homeostasis of A40025 and A400opt was found between 10 °C and 30 °C growth temperatures, but sharp declines were recorded at 5 and 35 °C. This homeostasis was achieved in part through modifications to leaf nitrogen content, which increased at extreme temperatures. Significant changes were also recorded regarding nitrogen partitioning in the photosynthetic apparatus and in the temperature dependence of photosynthetic parameters. The cultivars differed only in terms of the temperature response of photosynthetic parameters, with Mediterranean genotypes displaying a greater sensitivity of the maximum rate of Rubisco carboxylation to elevated temperatures. It was concluded that intra-specific variations in the temperature acclimation of photosynthesis exist among alfalfa cultivars, but that

  19. The contribution of greenhouse gases to the recent slowdown in global-mean temperature trends

    NASA Astrophysics Data System (ADS)

    Checa-Garcia, R.; Shine, K. P.; Hegglin, M. I.

    2016-09-01

    The recent slowdown in the rate of increase in global-mean surface temperature (GMST) has generated extensive discussion, but little attention has been given to the contribution of time-varying trends in greenhouse gas concentrations. We use a simple model approach to quantify this contribution. Between 1985 and 2003, greenhouse gases (including well-mixed greenhouse gases, tropospheric and stratospheric ozone, and stratospheric water vapour from methane oxidation) caused a reduction in GMST trend of around 0.03-0.05 K decade-1 which is around 18%-25% of the observed trend over that period. The main contributors to this reduction are the rapid change in the growth rates of ozone-depleting gases (with this contribution slightly opposed by stratospheric ozone depletion itself) and the weakening in growth rates of methane and tropospheric ozone radiative forcing. Although CO2 is the dominant greenhouse gas contributor to GMST trends, the continued increase in CO2 concentrations offsets only about 30% of the simulated trend reduction due to these other contributors. These results emphasize that trends in non-CO2 greenhouse gas concentrations can make significant positive and negative contributions to changes in the rate of warming, and that they need to be considered more closely in analyses of the causes of such variations.

  20. Temporal variation in temperature determines disease spread and maintenance in Paramecium microcosm populations.

    PubMed

    Duncan, Alison B; Fellous, Simon; Kaltz, Oliver

    2011-11-22

    The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host-parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Infected and uninfected populations of two P. caudatum genotypes were created and four constant temperature treatments (26°C, 28°C, 30°C and 32°C) compared with four variable treatments with the same mean temperatures. Variable temperature treatments were achieved by alternating populations between permissive (23°C) and restrictive (35°C) conditions daily over 30 days. Variable conditions and high temperatures caused greater declines in Paramecium populations, greater fluctuations in population size and higher incidence of extinction. The additional effect of parasite infection was additive and enhanced the negative effects of the variable environment and higher temperatures by up to 50 per cent. The variable environment and high temperatures also caused a decrease in parasite prevalence (up to 40%) and an increase in extinction (absence of detection) (up to 30%). The host genotypes responded similarly to the different environmental stresses and their effect on parasite traits were generally in the same direction. This work provides, to our knowledge, the first experimental demonstration that epidemiological dynamics are influenced by environmental variation. We also emphasize the need to consider environmental variance, as well as means, when trying to understand, or predict population dynamics or range.

  1. Temporal variation in temperature determines disease spread and maintenance in Paramecium microcosm populations

    PubMed Central

    Duncan, Alison B.; Fellous, Simon; Kaltz, Oliver

    2011-01-01

    The environment is rarely constant and organisms are exposed to temporal and spatial variations that impact their life histories and inter-species interactions. It is important to understand how such variations affect epidemiological dynamics in host–parasite systems. We explored effects of temporal variation in temperature on experimental microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata. Infected and uninfected populations of two P. caudatum genotypes were created and four constant temperature treatments (26°C, 28°C, 30°C and 32°C) compared with four variable treatments with the same mean temperatures. Variable temperature treatments were achieved by alternating populations between permissive (23°C) and restrictive (35°C) conditions daily over 30 days. Variable conditions and high temperatures caused greater declines in Paramecium populations, greater fluctuations in population size and higher incidence of extinction. The additional effect of parasite infection was additive and enhanced the negative effects of the variable environment and higher temperatures by up to 50 per cent. The variable environment and high temperatures also caused a decrease in parasite prevalence (up to 40%) and an increase in extinction (absence of detection) (up to 30%). The host genotypes responded similarly to the different environmental stresses and their effect on parasite traits were generally in the same direction. This work provides, to our knowledge, the first experimental demonstration that epidemiological dynamics are influenced by environmental variation. We also emphasize the need to consider environmental variance, as well as means, when trying to understand, or predict population dynamics or range. PMID:21450730

  2. Phenotypic plasticity and biogeographic variation in physiology of habitat-forming seaweed: response to temperature and nitrate.

    PubMed

    Flukes, Emma B; Wright, Jeffrey T; Johnson, Craig R

    2015-10-01

    Southeastern Australian waters are warming at nearly four times the global average rate (~0.7°C · century(-1) ) driven by strengthening incursions of the warm oligotrophic East Australian Current. The growth rate hypothesis (GRH) predicts that nutrient depletion will impact more severely on seaweeds at high latitudes with compressed growth seasons. This study investigates the effects of temperature and nutrients on the ecophysiology of the habitat-forming seaweed Phyllospora comosa in a laboratory experiment using temperature (12°C, 17°C, 22°C) and nutrient (0.5, 1.0, 3.0 μM NO3 (-) ) scenarios representative of observed variation among geographic regions. Changes in growth, photosynthetic characteristics (via chlorophyll fluorescence), pigment content, tissue chemistry (δ(13) C, % C, % N, C:N) and nucleic acid characteristics (absolute RNA and DNA, RNA:DNA ratios) were determined in seaweeds derived from cool, high-latitude and warm, low-latitude portions of the species' range. Performance of P. comosa was unaffected by nitrate availability but was strongly temperature-dependent, with photosynthetic efficiency, growth, and survival significantly impaired at 22°C. While some physiological processes (photosynthesis, nucleic acid, and accessory pigment synthesis) responded rapidly to temperature, others (C/N dynamics, carbon concentrating processes) were largely invariant and biogeographic variation in these characteristics may only occur through genetic adaptation. No link was detected between nutrient availability, RNA synthesis and growth, and the GRH was not supported in this species. While P. comosa at high latitudes may be less susceptible to oligotrophy than predicted by the GRH, warming water temperatures will have deleterious effects on this species across its range unless rapid adaptation is possible. PMID:26986886

  3. Segregating variation for temperature-dependent sex determination in a lizard

    PubMed Central

    Rhen, T; Schroeder, A; Sakata, J T; Huang, V; Crews, D

    2011-01-01

    Temperature-dependent sex determination (TSD) was first reported in 1966 in an African lizard. It has since been shown that TSD occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. Extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. Research in TSD species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad differentiation. Nevertheless, the mechanism that actually transduces temperature into a biological signal for ovary versus testis development is not known in any species. Classical genetics could be used to identify the loci underlying TSD, but only if there is segregating variation for TSD. Here, we use the ‘animal model' to analyze inheritance of sexual phenotype in a 13-generation pedigree of captive leopard geckos, Eublepharis macularius, a TSD reptile. We directly show genetic variance and genotype-by-temperature interactions for sex determination. Additive genetic variation was significant at a temperature that produces a female-biased sex ratio (30 °C), but not at a temperature that produces a male-biased sex ratio (32.5 °C). Conversely, dominance variance was significant at the male-biased temperature (32.5 °C), but not at the female-biased temperature (30 °C). Non-genetic maternal effects on sex determination were negligible in comparison with additive genetic variance, dominance variance and the primary effect of temperature. These data show for the first time that there is segregating variation for TSD in a reptile and consequently that a quantitative trait locus analysis would be practicable for identifying the genes underlying TSD. PMID:20700140

  4. U.S.DOE Global Monthly Station Temperature and Precipitation, 1738-1980

    DOE Data Explorer

    The global monthly station temperature and precipitation data from the U.S. Department of Energy, a dataset hosted at, covers the time period from January, 1738 to December, 1980. The air temperature and precipitation levels are platform observations from ground and water surfaces. The data are maintained in the Research Data Archive at the National Center for Atmospheric Research.

  5. Polarization nonreciprocity suppression of dual-polarization fiber-optic gyroscope under temperature variation.

    PubMed

    Lu, Ping; Wang, Zinan; Luo, Rongya; Zhao, Dayu; Peng, Chao; Li, Zhengbin

    2015-04-15

    Polarization nonreciprocity (PN) is one of the most critical factors that degrades the performance of interferometric fiber-optic gyroscopes (IFOGs), particularly under varying temperature. We present an experimental investigation of PN error suppression in a dual-polarization IFOG. Both experimental results and theoretical analysis indicate that the PN errors of the two orthogonally polarized light waves always have opposite signs that can be effectively compensated despite the temperature variation. As a result, the long-term stability of the IFOG has been significantly improved. This study is promising for reducing the temperature fragility of IFOGs.

  6. Global Failure Modes in High Temperature Composite Structures

    NASA Technical Reports Server (NTRS)

    Knauss, W. G.

    1998-01-01

    Composite materials have been considered for many years as the major advance in the construction of energy efficient aerospace structures. Notable advances have been made in understanding the special design considerations that set composites apart from the usual "isotropic" engineering materials such as the metals. As a result, a number of significant engineering designs have been accomplished. However, one shortcoming of the currently favored composites is their relatively unforgiving behavior with respect to failure (brittleness) under seemingly mild impact conditions and large efforts are underway to rectify that situation, much along the lines of introducing thermoplastic matrix materials. Because of their relatively more pronounced (thermo) viscoelastic behavior these materials respond with "toughness" in fracture situations. From the point of view of applications requiring material strength, this property is highly desirable. This feature impacts several important and distinct engineering problems which have been' considered under this grant and cover the 1) effect of impact damage on structural (buckling) stability of composite panels, the 2) effect of time dependence on the progression of buckling instabilities, and the 3) evolution of damage and fracture at generic thickness discontinuities in structures. The latter topic has serious implications for structural stability problems (buckling failure in reinforced shell structures) as well as failure progression in stringer-reinforced shell structures. This grant has dealt with these issues. Polymer "toughness" is usually associated with uncrosslinked or thermo-plastic polymers. But, by comparison with their thermoset counterparts they tend to exhibit more pronounced time dependent material behavior; also, that time dependence can occur at lower temperatures which places restriction in the high temperature use of these "newer and tougher" materials that are not quite so serious with the thermoset matrix

  7. Local Variations in the 13-Suess Effect: A Global and Regional Phenomenon

    NASA Astrophysics Data System (ADS)

    Swart, P. K.; Okazaki, R.; Waite, A.

    2012-12-01

    The burning of fossil fuel has lowered the δ13C of the atmosphere, a change which is visible in the δ13C of dissolved inorganic carbon in the oceans. Although atmospheric measurements of the δ13C of CO2 have only been routine since 1980, the rate of change in atmospheric δ13C since the start of the industrial revolution can be monitored by measuring the δ13C of skeletal organisms such as sclerosponges and corals. For example, by fitting a polynomial equation to the δ13C data from sclerosponges and then determining the first derivative, a rate of change in δ13C can be calculated which increases from -0.001‰/yr in 1850 to -0.009‰/yr in 1960, and -0.026‰/yr at the present day. In comparison the decrease at the present day in the Pacific is significantly lower (-0.01‰/yr). Although shallow water corals from the Atlantic also show the same overall changes in the δ13C, there are locations such as in the Florida Keys, where the rates of change over the past 50 years have been much greater than the global rate. For example, the rate of change between 1960 and 1990 in two different corals examined growing in Florida Bay was -0.045 and -0.06‰/yr respectively, significantly greater than -0.026. Since 1990 however there have been no further decreases in the δ13C of these corals with the result that the change between 1960 and 2010 agrees with the global change. The high rates of change in δ13C this coral and in fact all the corals in Florida, are punctuated by periods during which the change is considerably less than the rate calculated from the sclerosponge data. We propose that these oscillations result from varying delivery of terrestrial organic material to the coastal zone, probably brought about by variations in water delivery and hence local/regional precipitation. During times of enhanced delivery the δ13C of the coastal dissolved inorganic carbon and hence the δ13C of the corals decreases at a faster rate than the global rate. During periods of

  8. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  9. Simultaneous Global Pressure and Temperature Measurement Technique for Hypersonic Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M.

    2000-01-01

    High-temperature luminescent coatings are being developed and applied for simultaneous pressure and temperature mapping in conventional-type hypersonic wind tunnels, providing global pressure as well as Global aeroheating measurements. Together, with advanced model fabrication and analysis methods, these techniques will provide a more rapid and complete experimental aerodynamic and aerothermodynamic database for future aerospace vehicles. The current status in development of simultaneous pressure- and temperature-sensitive coatings and measurement techniques for hypersonic wind tunnels at Langley Research Center is described. and initial results from a feasibility study in the Langley 31-Inch Mach 10 Tunnel are presented.

  10. Temperature Variations in the Martian Upper Atmosphere from the MAVEN Neutral Gas and Ion Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Stone, Shane W.; Yelle, Roger; Mahaffy, Paul; Benna, Mehdi; Elrod, Meredith K.; Bougher, Stephen W.; MAVEN

    2016-10-01

    The MAVEN Neutral Gas and Ion Mass Spectrometer (NGIMS) measures composition and variability of neutral and ionic species in the Martian upper atmosphere, allowing us to calculate neutral temperatures from roughly 130 km to 300 km above the surface. Over the past two years at Mars, NGIMS has collected an extensive and useful data set that covers much of the Martian thermosphere and exosphere. We use new, improved algorithms for the most accurate determination of densities from the NGIMS data. We use the densities of inert species (specifically CO2, Ar, and N2) along with a hydrostatic equilibrium model to infer the temperature profile and its uncertainty. Uncertainties include the errors in the density measurements, unknown upper boundary conditions, and horizontal variations in the atmosphere. Our calculations reveal diurnal temperature variations of up to 90 K and maximum latitudinal temperature variations of 130 K. These fluctuations in temperature in the upper atmosphere are surprising because they are significantly larger than those predicted by the latest 3D general circulation models for Mars.

  11. The influence of temperature variations on ultrasonic guided waves in anisotropic CFRP plates.

    PubMed

    Putkis, O; Dalton, R P; Croxford, A J

    2015-07-01

    Carbon Fibre Reinforced Polymer (CFRP) materials are lightweight and corrosion-resistant and therefore are increasingly used in aerospace, automotive and construction industries. In Structural Health Monitoring (SHM) applications of CFRP materials, ultrasonic guided waves potentially offer large area inspection or inspection from a remote location. This paper addresses the effect of temperature variation on guided wave propagation in highly anisotropic CFRP materials. Temperature variations cause changes in guided wave velocity that can in turn compromise the baseline subtraction procedures employed by many SHM systems for damage detection. A simple model that describes the dependence of elastic properties of the CFRP plates on temperature is presented in this paper. The model can be used to predict anisotropic velocity changes and baseline subtraction performance under varying thermal conditions. The results produced by the model for unidirectional and 0/90 CFRP plates are compared with experimental measurements. PMID:25812468

  12. The influence of temperature variations on ultrasonic guided waves in anisotropic CFRP plates.

    PubMed

    Putkis, O; Dalton, R P; Croxford, A J

    2015-07-01

    Carbon Fibre Reinforced Polymer (CFRP) materials are lightweight and corrosion-resistant and therefore are increasingly used in aerospace, automotive and construction industries. In Structural Health Monitoring (SHM) applications of CFRP materials, ultrasonic guided waves potentially offer large area inspection or inspection from a remote location. This paper addresses the effect of temperature variation on guided wave propagation in highly anisotropic CFRP materials. Temperature variations cause changes in guided wave velocity that can in turn compromise the baseline subtraction procedures employed by many SHM systems for damage detection. A simple model that describes the dependence of elastic properties of the CFRP plates on temperature is presented in this paper. The model can be used to predict anisotropic velocity changes and baseline subtraction performance under varying thermal conditions. The results produced by the model for unidirectional and 0/90 CFRP plates are compared with experimental measurements.

  13. Multi-decadal aerosol variations from 1980 to 2009: a perspective from observations and a global model

    NASA Astrophysics Data System (ADS)

    Chin, M.; Diehl, T.; Tan, Q.; Prospero, J. M.; Kahn, R. A.; Remer, L. A.; Yu, H.; Sayer, A. M.; Bian, H.; Geogdzhayev, I. V.; Holben, B. N.; Howell, S. G.; Huebert, B. J.; Hsu, N. C.; Kim, D.; Kucsera, T. L.; Levy, R. C.; Mishchenko, M. I.; Pan, X.; Quinn, P. K.; Schuster, G. L.; Streets, D. G.; Strode, S. A.; Torres, O.; Zhao, X.-P.

    2014-04-01

    Aerosol variations and trends over different land and ocean regions from 1980 to 2009 are analyzed with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model and observations from multiple satellite sensors and available ground-based networks. Excluding time periods with large volcanic influence, aerosol optical depth (AOD) and surface concentration over polluted land regions generally vary with anthropogenic emissions, but the magnitude of this association can be dampened by the presence of natural aerosols, especially dust. Over the 30-year period in this study, the largest reduction in aerosol levels occurs over Europe, where AOD has decreased by 40-60% on average and surface sulfate concentrations have declined by a factor of up to 3-4. In contrast, East Asia and South Asia show AOD increases, but the relatively high level of dust aerosols in Asia reduces the correlation between AOD and pollutant emission trends. Over major dust source regions, model analysis indicates that the change of dust emissions over the Sahara and Sahel has been predominantly driven by the change of near-surface wind speed, but over Central Asia it has been largely influenced by the change of the surface wetness. The decreasing dust trend in the North African dust outflow region of the tropical North Atlantic and the receptor sites of Barbados and Miami is closely associated with an increase of the sea surface temperature in the North Atlantic. This temperature increase may drive the decrease of the wind velocity over North Africa, which reduces the dust emission, and the increase of precipitation over the tropical North Atlantic, which enhances dust removal during transport. Despite significant trends over some major continental source regions, the model-calculated global annual average AOD shows little change over land and ocean in the past three decades, because opposite trends in different land regions cancel each other out in the global average, and changes over

  14. Sustained attention to local and global target features is different: performance and tympanic membrane temperature.

    PubMed

    Helton, William S; Hayrynen, Lauren; Schaeffer, David

    2009-10-01

    Vision researchers have investigated the differences between global and local feature perception. No one has, however, examined the role of global and local feature discrimination in sustained attention tasks. In this experiment participants performed a sustained attention task requiring either global or local letter target discriminations or watched the same displays without any work imperative. Reaction time to targets was slower when global feature discriminations were required than when local feature discriminations were required. Tympanic membrane temperature (TMT) was utilized in this study as an index of cerebral activation. Participants in the global letter detection condition had elevated post-task right TMT, indicative of reduced cerebral activation in the right hemisphere, in comparison to participants in the local letter detection or no-work imperative conditions. Both the performance and physiological results of this study indicate increased cognitive fatigue when global feature discriminations are required.

  15. Seasonal temperature variations observed by Cassini-VIMS on Saturn's satellites

    NASA Astrophysics Data System (ADS)

    Filacchione, Gianrico; Capaccioni, Fabrizio; D'Aversa, Emiliano; Tosi, Federico; Ciarniello, Mauro; Clark, Roger N.; Brown, Robert H.; Buratti, Bonnie J.; Cruikshank, Dale P.; Dalle Ore, Cristina M.; Scipioni, Francesca; Cerroni, Priscilla

    2015-04-01

    We report about temperature maps of Mimas, Enceladus, Tethys, Dione and Rhea derived from Cassini/VIMS data. Observations taken during the entire duration of the Cassini mission (2004-2014) were processed. Since equinox occurred in 2009, this dataset includes both pre and post equinox viewing geometries. VIMS data taken at spatial resolution of 20-40 km/pixel allow us to study the correlation of the temperature at regional scale resolution with solar illumination conditions, geological features and seasons. The retrieval of the temperature from IR reflectance data is based on the comparison with laboratory measurements (Clark et al., Icarus 218, 831, 2012): when a sample of pure crystalline water ice particles is cooled, the 3.6 µm peak moves towards shorter wavelengths, from about 3.65 µm at T=123 K to about 3.55 µm at T=88 K. Mastrapa et al. (ApJ 701, 104, 2009) have measured a similar trend also in the imaginary part (k) of the refractive index of water ice when a sample is cooled from T=140 K to 20 K. Being Saturn's satellites surfaces dominated by water ice (Filacchione et al., Icarus 220, 1064, 2012), the measurement of the wavelength at which the 3.6 µm reflectance peak occurs can be considered as a good temperature marker. This method was already applied to Saturn rings VIMS mosaics to retrieve ring particles temperature (Filacchione et al., Icarus 241, 45, 2014). By using geometry projection techniques applied to VIMS data, we have mapped temperature variations as a function of LST and season on the regular satellites surfaces. Pre and post-equinox temperature maps built at the same LST allow us to follow seasonal variations across summer and winter hemispheres. Moreover, temperature variations seen across satellites surfaces appear correlated with geological features, leading-trailing asymmetries, local color patterns and equatorial radiation lenses.

  16. Pliocene three-dimensional global ocean temperature reconstruction

    USGS Publications Warehouse

    Dowsett, H.J.; Robinson, M.M.; Foley, K.M.

    2009-01-01

    A snapshot of the thermal structure of the mid-Piacenzian ocean is obtained by combining the Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM3) multiproxy sea-surface temperature (SST) reconstruction with bottom water tempera-5 ture estimates produced using Mg/Ca paleothermometry. This reconstruction assumes a Pliocene water mass framework similar to that which exists today, with several important modifications. The area of formation of present day North Atlantic Deep Water (NADW) was expanded and extended further north toward the Arctic Ocean during the mid-Piacenzian relative to today. This, combined with a deeper Greenland-Scotland Ridge, allowed a greater volume of warmer NADW to enter the Atlantic Ocean. In the Southern Ocean, the Polar Front Zone was expanded relative to present day, but shifted closer to the Antarctic continent. This, combined with at least seasonal reduction in sea ice extent, resulted in decreased Antarctic BottomWater (AABW) production (relative to present day) as well as possible changes in the depth of intermediate wa15 ters. The reconstructed mid-Piacenzian three-dimensional ocean was warmer overall than today, and the hypothesized aerial extent of water masses appears to fit the limited stable isotopic data available for this time period. ?? Author(s) 2009.

  17. Central European temperature variations over the past two millennia recorded in a stalagmite from western Switzerland

    NASA Astrophysics Data System (ADS)

    Fleitmann, Dominik; Hasenfratz, Adam; Häuselmann, Anamaria; Lehner, Flavio; Cheng, Hai; Edwards, Lawrence; Leuenberger, Markus; Raible, Christoph C.; Broecker, Jochen; Luterbacher, Jürg

    2016-04-01

    European temperature reconstructions covering the last two millennia are almost entirely based on tree rings and therefore clearly biased towards summer. Reconstructions of mean annual air or cold season temperatures are much rarer. To fill this distinct data gap, we present a bi-annually resolved 2000 year-long speleothem-based oxygen isotope (δ18O) record from Milandre Cave in western Switzerland. Calibration of the Milandre Cave δ18O record using observational and reconstructed temperature data reveals that calcite δ18O values are closely related to changes in cold-season (fall-winter-spring) temperatures. The M6 δ18O record unveils temperature variations of up to 2°C during the last two millennia, with the temperature difference between the warmest decade of the Medieval Climate Anomaly (950-1250 CE) and the coldest decade of the Little Ice Age (1400-1700 CE) amounting to ~1.7°C. In general, higher cold season temperatures prevailed between 450 and 600 CE and 1000 and1150 CE. Lower temperatures were recorded between 650 and 900 CE and 1350 and1700 CE. Modeled cold season temperatures for the past millennium compare remarkably well with our reconstruction, and confirm the importance of both, solar forcing and internal variability, in driving Central European cold season temperatures.

  18. Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats

    PubMed Central

    Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

    2016-01-01

    Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming. PMID:27540589

  19. Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats.

    PubMed

    Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

    2016-08-01

    Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming. PMID:27540589

  20. Rising sea levels will reduce extreme temperature variations in tide-dominated reef habitats.

    PubMed

    Lowe, Ryan Joseph; Pivan, Xavier; Falter, James; Symonds, Graham; Gruber, Renee

    2016-08-01

    Temperatures within shallow reefs often differ substantially from those in the surrounding ocean; therefore, predicting future patterns of thermal stresses and bleaching at the scale of reefs depends on accurately predicting reef heat budgets. We present a new framework for quantifying how tidal and solar heating cycles interact with reef morphology to control diurnal temperature extremes within shallow, tidally forced reefs. Using data from northwestern Australia, we construct a heat budget model to investigate how frequency differences between the dominant lunar semidiurnal tide and diurnal solar cycle drive ~15-day modulations in diurnal temperature extremes. The model is extended to show how reefs with tidal amplitudes comparable to their depth, relative to mean sea level, tend to experience the largest temperature extremes globally. As a consequence, we reveal how even a modest sea level rise can substantially reduce temperature extremes within tide-dominated reefs, thereby partially offsetting the local effects of future ocean warming.

  1. The Effects of Atmospheric Opacity on the Seasonal Variation of Martian Surface Temperature

    NASA Technical Reports Server (NTRS)

    Wilson, R. J.; Smith, M. D.

    2005-01-01

    The daily and seasonal variation of surface temperature is a central element in the description of martian climate. Surface thermal inertia and albedo are critical boundary inputs for simulating surface temperature in Mars general circulation models (MGCMs). Thermal inertia (TI) is also of intrinsic interest as it may be related to regolith properties such as particle size and surface character and so high spatial resolution is desirable. The recent mapping of TI at very high (0.25 deg) spatial resolution was achieved by fitting a thermal model to surface temperature observations obtained over a broad range of several martian years. However, varying atmospheric opacity (dust and water ice clouds) can significantly influence the estimated TI field and this effect was not fully compensated for. Opacity leads to an increase in morning temperature and a decrease in afternoon temperature, thus increasing the apparent thermal inertia.

  2. Correction of temperature-induced spectral variations by loading space standardization.

    PubMed

    Chen, Zeng-Ping; Morris, Julian; Martin, Elaine

    2005-03-01

    With a view to maintaining the validity of multivariate calibration models for chemical processes affected by temperature fluctuations, loading space standardization (LSS) is proposed. Through the application of LSS, multivariate calibration models built at temperatures other than those of the test samples can provide predictions with an accuracy comparable to the results obtained at a constant temperature. Compared with other methods, designed for the same purpose, such as continuous piecewise direct standardization, LSS has the advantages of straightforward implementation and good performance. The methodology was applied to shortwave NIR spectral data sets measured at different temperatures. The results showed that LSS can effectively remove the influence of temperature variations on the spectra and maintain the predictive abilities of the multivariate calibration models.

  3. Turbulent forced convection with sinusoidal variation of inlet temperature between two parallel-plates

    SciTech Connect

    Arik, M.; Kakac, S.; Santos, C.A.C.

    1996-12-01

    The thermal entry region heat transfer due to turbulent forced convection, subjected to a sinusoidally varying inlet temperature is solved by employing a hybrid numerical-analytical solution technique under linear variation of wall temperature and constant wall temperature as boundary condition and is verified with the experimental results. The analytical solution of the problem is obtained through extending the generalized integral transform technique. An experimental set-up was built and used in order to validate the employed mathematical modeling. Analytical solutions are compared with the experimental findings. Satisfactory agreement is obtained between theoretically and experimentally determined heat transfer characteristics for different axial positions along the channel. Heat transfer characteristics of flow have been determined for linear wall temperature and constant wall temperature boundary conditions. Results obtained from the analytical-numerical solution technique and experimental studies have been presented in graphical and tabular forms.

  4. Latitudinal variation in carbon storage can help predict changes in swamps affected by global warming

    USGS Publications Warehouse

    Middleton, Beth A.; McKee, Karen

    2004-01-01

    Plants may offer our best hope of removing greenhouse gases (gases that contribute to global warming) emitted to the atmosphere from the burning of fossil fuels. At the same time, global warming could change environments so that natural plant communities will either need to shift into cooler climate zones, or become extirpated (Prasad and Iverson, 1999; Crumpacker and others, 2001; Davis and Shaw, 2001). It is impossible to know the future, but studies combining field observation of production and modeling can help us make predictions about what may happen to these wetland communities in the future. Widespread wetland types such as baldcypress (Taxodium distichum) swamps in the southeastern portion of the United States could be especially good at carbon sequestration (amount of CO2 stored by forests) from the atmosphere. They have high levels of production and sometimes store undecomposed dead plant material in wet conditions with low oxygen, thus keeping gases stored that would otherwise be released into the atmosphere (fig. 1). To study the ability of baldcypress swamps to store carbon, our project has taken two approaches. The first analysis looked at published data to develop an idea (hypothesis) of how production levels change across a temperature gradient in the baldcypress region (published data study). The second study tested this idea by comparing production levels across a latitudinal range by using swamps in similar field conditions (ongoing carbon storage study). These studies will help us make predictions about the future ability of baldcypress swamps to store carbon in soil and plant biomass, as well as the ability of these forests to shift northward with global warming.

  5. Latitudinal Variation in Carbon Storage Can Help Predict Changes in Swamps Affected by Global Warming

    USGS Publications Warehouse

    Middleton, Beth A.; McKee, Karen

    2004-01-01

    Plants may offer our best hope of removing greenhouse gases (gases that contribute to global warming) emitted to the atmosphere from the burning of fossil fuels. At the same time, global warming could change environments so that natural plant communities will either need to shift into cooler climate zones, or become extirpated (Prasad and Iverson, 1999; Crumpacker and others, 2001; Davis and Shaw, 2001). It is impossible to know the future, but studies combining field observation of production and modeling can help us make predictions about what may happen to these wetland communities in the future. Widespread wetland types such as baldcypress (Taxodium distichum) swamps in the southeastern portion of the United States could be especially good at carbon sequestration (amount of CO2 stored by forests) from the atmosphere. They have high levels of production and sometimes store undecomposed dead plant material in wet conditions with low oxygen, thus keeping gases stored that would otherwise be released into the atmosphere (fig. 1). To study the ability of baldcypress swamps to store carbon, our project has taken two approaches. The first analysis looked at published data to develop an idea (hypothesis) of how production levels change across a temperature gradient in the baldcypress region (published data study). The second study tested this idea by comparing production levels across a latitudinal range by using swamps in similar field conditions (ongoing carbon storage study). These studies will help us make predictions about the future ability of baldcypress swamps to store carbon in soil and plant biomass, as well as the ability of these forests to shift northward with global warming.

  6. Seasonal variation in home blood pressure measurements and relation to outside temperature in Japan.

    PubMed

    Hozawa, Atsushi; Kuriyama, Shinichi; Shimazu, Taichi; Ohmori-Matsuda, Kaori; Tsuji, Ichiro

    2011-01-01

    Previous studies have suggested that outside temperature affects blood pressure (BP) levels. However, recently, due to a spreading heating system, the seasonal variation in BP levels might be smaller, especially in colder seasons when more heat is used. We used continuous measurements of home BP data to track seasonal variations of BP to analyze the relation between outside temperature and BP values. Among 213 volunteers who were asked to measure BP in September 2000, 79 participants (mean age 72.7 years, 60.0% women) measured BP at least once per month until August 2003 (36 months). The mean number of measurements was 19.0 times/month. Information on outside temperature was provided by the Japan Meteorological Agency. We used general linear models to analyze the relation between outside temperature and BP values. Blood pressure levels were lowest in the warmest months. However, the highest BP levels were not observed in the coldest month, but rather in March. A clear inverse association between temperature and BP values was evident only in periods when outside temperatures were above 10°C. When the outside temperature was ≥ 10°C, 1°C increment of outside temperature correspond to 0.40 and 0.28 mmHg decrease of systolic blood pressure (SBP) and diastolic blood pressure (DBP), whereas the corresponding values were 0.06 and 0.01 mmHg when the outside temperature was <10°C. In conclusion, inverse association between outside temperature and BP was observed only in warmer seasons.

  7. Global model of P-wave speed variations in Earth's mantle

    NASA Astrophysics Data System (ADS)

    van der Hilst, R. D.; Li, C.

    2005-12-01

    Using data from different seismic phases and improved tomography codes we have constructed a new model of 3-D variations in P-wavespeed in Earth's mantle. First, we improve data coverage by adding to the large volume of routinely processed ISC catalog (P, pP, PKP ) data, as reprocessed by Engdahl et al. (BSSA98), travel time residuals from several regional networks in SE Asia, several sets of differential travel times that have been measured by waveform cross correlation. These data include PKP-Pdiff (Wysession) and various PKP branches (Creager and McSweeney), which help improve resolution of structure in the deepest mantle, and PP-P (Bolton and Masters), which greatly improves the mapping of structure in the upper mantle away from belts of high seismic activity. Second, we follow Kerason et al. (JGR01) and use 3-D sensitivity kernels to account for the fact that these data are measured at different frequency, and in different ways. The kernels allow low frequency data (e.g., PP-P, Pdiff) to constrain long wavelengths without preventing short period data (P, PKP) to resolve small scale structure. We use approximate kernels since our research has shown that for this application the precise shape of the kernels is less important than effects of parameterization, regularization, and data quality. Third, the localization of sensitivity is further aided by the use of a grid that is adapted to sampling density. Fourth, for the ray geometry part we use 3-D ray tracing to account for the affects of heterogeneity on ray geometry. Finally, we correct for 3-D variations in crust structure, using the global model CRUST2.0 and more detailed regional models, where available. This correction reduces the artificial smearing of shallow structure along steep ray paths. We present the new model, along with resolution tests, and discuss differences and similarities with other global models, with emphasis on the structure of presumed 'slabs' of subducted lithosphere and 'plumes' of

  8. The relationship between global palaeointensity variations and geodynamics: documenting the evolutionary cycle of Pangaea

    NASA Astrophysics Data System (ADS)

    Biggin, A.; Thomas, N.

    2003-04-01

    Long-term variations in the geomagnetic field palaeointensity (PI) are fundamentally linked to global geodynamics through a chain of events commencing with intense plate tectonic activity at the surface and culminating in changes in the pattern of outer core convection which essentially control the field intensity. Therefore, establishing a reliable palaeointensity record over geological timescales can provide a valuable source of information in documenting broad geodynamic changes such as the evolutionary cycle of supercontinents. In this paper, we present an interpretation of palaeointensity variation for the 400--100 Ma period, based on a detailed statistical analysis of the PINT global palaeointensity database. We link palaeointensity changes to four major stages in the evolutionary cycle of Pangaea. (1) From 400 to 350 Ma, during supercontinent amalgamation, the PI is low reflecting low heat flux, a hot lowermost mantle (LMM) and layered mantle convection. (2) Between 350 and 250 Ma, the PI initially rose rapidly reflecting increased heat flux resulting from cooling of the LMM achieved by catastrophic avalanching of ancient subducted ocean crust following a period of ponding at the 660 km boundary layer. Subsequently, from 325--250 Ma, PI decreased reflecting decreased heat flux across the CMB, which we interpret as a response to mantle restabilisation and warming. (3) From 250--175 Ma the PI was generally low in response to mantle insulation during a period of supercontinent assembly when the mantle became very hot. (4) The final period in the evolutionary cycle, from 180--10 Ma, is initially characterised by a gradual rise in PI (175--120 Ma) which is interpreted as being a response to the introduction of cold material into the lower mantle following widespread subduction during the dispersal of Pangaea. Subsequently, from 120--10 Ma, PI appears to have risen to a peak at around 50 Ma, then decreased, possibly documenting another catastrophic mantle

  9. Prediction of Seasonal Climate-induced Variations in Global Food Production

    NASA Technical Reports Server (NTRS)

    Iizumi, Toshichika; Sakuma, Hirofumi; Yokozawa, Masayuki; Luo, Jing-Jia; Challinor, Andrew J.; Brown, Molly E.; Sakurai, Gen; Yamagata, Toshio

    2013-01-01

    Consumers, including the poor in many countries, are increasingly dependent on food imports and are therefore exposed to variations in yields, production, and export prices in the major food-producing regions of the world. National governments and commercial entities are paying increased attention to the cropping forecasts of major food-exporting countries as well as to their own domestic food production. Given the increased volatility of food markets and the rising incidence of climatic extremes affecting food production, food price spikes may increase in prevalence in future years. Here we present a global assessment of the reliability of crop failure hindcasts for major crops at two lead times derived by linking ensemble seasonal climatic forecasts with statistical crop models. We assessed the reliability of hindcasts (i.e., retrospective forecasts for the past) of crop yield loss relative to the previous year for two lead times. Pre-season yield predictions employ climatic forecasts and have lead times of approximately 3 to 5 months for providing information regarding variations in yields for the coming cropping season. Within-season yield predictions use climatic forecasts with lead times of 1 to 3 months. Pre-season predictions can be of value to national governments and commercial concerns, complemented by subsequent updates from within-season predictions. The latter incorporate information on the most recent climatic data for the upcoming period of reproductive growth. In addition to such predictions, hindcasts using observations from satellites were performed to demonstrate the upper limit of the reliability of crop forecasting.

  10. Does sunspot numbers cause global temperatures? A reconsideration using non-parametric causality tests

    NASA Astrophysics Data System (ADS)

    Hassani, Hossein; Huang, Xu; Gupta, Rangan; Ghodsi, Mansi

    2016-10-01

    In a recent paper, Gupta et al., (2015), analyzed whether sunspot numbers cause global temperatures based on monthly data covering the period 1880:1-2013:9. The authors find that standard time domain Granger causality test fails to reject the null hypothesis that sunspot numbers do not cause global temperatures for both full and sub-samples, namely 1880:1-1936:2, ​1936:3-1986:11 and 1986:12-2013:9 (identified based on tests of structural breaks). However, frequency domain causality test detects predictability for the full-sample at short (2-2.6 months) cycle lengths, but not the sub-samples. But since, full-sample causality cannot be relied upon due to structural breaks, Gupta et al., (2015) conclude that the evidence of causality running from sunspot numbers to global temperatures is weak and inconclusive. Given the importance of the issue of global warming, our current paper aims to revisit this issue of whether sunspot numbers cause global temperatures, using the same data set and sub-samples used by Gupta et al., (2015), based on an nonparametric Singular Spectrum Analysis (SSA)-based causality test. Based on this test, we however, show that sunspot numbers have predictive ability for global temperatures for the three sub-samples, over and above the full-sample. Thus, generally speaking, our non-parametric SSA-based causality test outperformed both time domain and frequency domain causality tests and highlighted that sunspot numbers have always been important in predicting global temperatures.

  11. Dynamic responses of atmospheric carbon dioxide concentration to global temperature changes between 1850 and 2010

    NASA Astrophysics Data System (ADS)

    Wang, Weile; Nemani, Ramakrishna

    2016-02-01

    Changes in Earth's temperature have significant impacts on the global carbon cycle that vary at different time scales, yet to quantify such impacts with a simple scheme is traditionally deemed difficult. Here, we show that, by incorporating a temperature sensitivity parameter (1.64 ppm yr-1 °C-1) into a simple linear carbon-cycle model, we can accurately characterize the dynamic responses of atmospheric carbon dioxide (CO2) concentration to anthropogenic carbon emissions and global temperature changes between 1850 and 2010 ( r 2 > 0.96 and the root-mean-square error < 1 ppm for the period from 1960 onward). Analytical analysis also indicates that the multiplication of the parameter with the response time of the atmospheric carbon reservoir (~12 year) approximates the long-term temperature sensitivity of global atmospheric CO2 concentration (~15 ppm °C-1), generally consistent with previous estimates based on reconstructed CO2 and climate records over the Little Ice Age. Our results suggest that recent increases in global surface temperatures, which accelerate the release of carbon from the surface reservoirs into the atmosphere, have partially offset surface carbon uptakes enhanced by the elevated atmospheric CO2 concentration and slowed the net rate of atmospheric CO2 sequestration by global land and oceans by ~30% since the 1960s. The linear modeling framework outlined in this paper thus provides a useful tool to diagnose the observed atmospheric CO2 dynamics and monitor their future changes.

  12. On interannual variations of the winter temperature at Faraday/Vernadsky Antarctic Station

    NASA Astrophysics Data System (ADS)

    Evtushevsky, A.; Kravchenko, V.; Grytsai, A.; Milinevsky, G.

    2009-04-01

    The interannual variations of the winter temperature at Faraday/Vernadsky Station, West Antarctic Peninsula are investigated. The meteorological READER surface air temperature and wind velocity/direction data for 1947-2007 period as well as the temperature and zonal/meridional wind distribution at 1000 hPa from the NCEP-NCAR reanalysis data (1979-2007) were used. The possible reasons of observed winter warming are discussed. The winter warming is accompanied by narrowing of the temperature variation range between -14°C and -4°C during 1950s to -8°C and -4°C in last decade. Positive trend in annual mean and winter mean temperature corresponds to lowering of the "depth" of cold winter anomalies, which can relate to the area located to the east of Antarctic Peninsula. The indications are seen from agreement between the interannual variations in winter temperature at Faraday/Vernadsky and the east-west migrations of quasistationary distribution of surface air temperature and zonal/meridional wind in Antarctic Peninsula region. The meteorological observations at Faraday/Vernadsky station display long-term changes in the wind distribution pattern: the appearance frequency of the "continental" wind (0°E±45° azimuth) observation has been reduced but the appearance frequency of the "ocean" wind (180°E±45° azimuth) has been increased threefold in the last two decades in comparison to 1950s-1970s. That is evidence of the structural change-over of circulation pattern in the region which is advantageous for warming. Results show that the changes in the quasistationary pattern in Antarctic troposphere contribute to the local climate change in Antarctic Peninsula region. The research was partly supported by National Taras Shevchenko University of Kyiv, project 06BF051-12.

  13. Natural variation in the temperature range permissive for vernalization in accessions of Arabidopsis thaliana.

    PubMed

    Wollenberg, Amanda C; Amasino, Richard M

    2012-12-01

    Vernalization is an acceleration of flowering in response to chilling, and is normally studied in the laboratory at near-freezing (2-4 °C) temperatures. Many vernalization-requiring species, such as Arabidopsis thaliana, are found in a range of habitats with varying winter temperatures. Natural variation in the temperature range that elicits a vernalization response in Arabidopsis has not been fully explored. We characterized the effect of intermediate temperatures (7-19 °C) on 15 accessions and the well-studied reference line Col-FRI. Although progressively warmer temperatures are gradually less effective at activating expression of the vernalization-specific gene VERNALIZATION-INSENSITIVE 3 (VIN3) and in accelerating flowering, there is substantial natural variation in the upper threshold (T(max) ) of the flowering-time response. VIN3 is required for the T(max) (13 °C) response of Col-FRI. Surprisingly, even 16 °C treatment caused induction of VIN3 in six tested lines, despite the ineffectiveness of this temperature in accelerating flowering for two of them. Finally, we present evidence that mild acceleration of flowering by 19 °C exposure may counterbalance the flowering time delay caused by non-inductive photoperiods in at least one accession, creating an appearance of photoperiod insensitivity.

  14. Egg size variation among tropical and temperate songbirds: An embryonic temperature hypothesis

    USGS Publications Warehouse

    Martin, T.E.

    2008-01-01

    Species with 'slow' life history strategies (long life, low fecundity) are thought to produce high-quality offspring by investing in larger, but fewer, young. Larger eggs are indeed associated with fewer eggs across taxa and can yield higher-quality offspring. Tropical passerines appear to follow theory because they commonly exhibit slow life history strategies and produce larger, but fewer, eggs compared with northern species. Yet, I show here that relative egg mass (corrected for adult mass) varies extensively in the tropics and subtropics for the same clutch size, and this variation is unexplained. I propose a hypothesis to explain egg size variation both within the tropics and between latitudes: Relative egg mass increases in species with cooler egg temperatures and longer embryonic periods to offset associated increases in energetic requirements of embryos. Egg temperatures of birds are determined by parental incubation behavior and are often cooler among tropical passerines because of reduced parental attentiveness of eggs. Here, I show that cooler egg temperatures and longer embryonic periods explained the enigmatic variation in egg mass within and among regions, based on field studies in tropical Venezuela (36 species), subtropical Argentina (16 species), and north temperate Arizona (20 species). Alternative explanations are not supported. Thus, large egg sizes may reflect compensation for increased energetic requirements of cool egg temperatures and long embryonic periods that result from reduced parental attentiveness in tropical birds. ?? 2008 by The National Academy of Sciences of the USA.

  15. The quasi-biennial variation in the geomagnetic field: a global characteristics analysis

    NASA Astrophysics Data System (ADS)

    Ou, Jiaming; Du, Aimin

    2016-04-01

    The periodicity of 1.5-3 years, namely the quasi-biennial oscillation (QBO), has been identified in the solar, geophysical, and atmospheric variability. Sugiura (1976) investigated the observatory annual means over 1900-1970 and confirmed the QBO in the geomagnetic field. At present, studying the quasi-biennial oscillation becomes substantial for separating the internal/external parts in the geomagnetic observations. For the internal field, two typical periodicities, namely the 6-year oscillation in the geomagnetic secular acceleration (SA) and the geomagnetic jerk (occurs in 1-2 years), have close period to the QBO. Recently, a global quasi-biennial fluctuation was identified in the geomagnetic core field model (Silva et al., 2012). Silva et al. speculated this 2.5 years signal to either external source remaining in the core field model or consequence of the methods used to construct the model. As more high-quality data from global observatories are available, it is a good opportunity to characterize the geomagnetic QBO in the global range. In this paper, we investigate the QBO in the observatory monthly geomagnetic field X, Y, and Z components spanning 1985-2010. We employ the observatory hourly means database from the World Data Center for Geomagnetism (WDC) for the investigation. Wavelet analysis is used to detect and identify the QBO, while Fast Fourier Transform (FFT) analysis to obtain the statistics of the QBO. We apply the spherical harmonic analysis on QBO's amplitude, in order to quantify and separate internal and external sources. Three salient periods respectively at 2.9, 2.2, and 1.7 years, are identified in the amplitude spectrum over 1988-2008. The oscillation with the period of ~2.2 years is most prominent in all field components and further studied. In the X component the QBO is attenuated towards the polar regions, while in the Z component the amplitude of QBO increases with increasing of the geomagnetic latitude. At the high latitudes, the QBO

  16. Variation in mortality of ischemic and hemorrhagic strokes in relation to high temperature

    NASA Astrophysics Data System (ADS)

    Lim, Youn-Hee; Kim, Ho; Hong, Yun-Chul

    2013-01-01

    Outdoor temperature has been reported to have a significant influence on the seasonal variations of stroke mortality, but few studies have investigated the effect of high temperature on the mortality of ischemic and hemorrhagic strokes. The main study goal was to examine the effect of temperature, particularly high temperature, on ischemic and hemorrhagic strokes. We investigated the association between outdoor temperature and stroke mortality in four metropolitan cities in Korea during 1992-2007. We used time series analysis of the age-adjusted mortality rate for ischemic and hemorrhagic stroke deaths by using generalized additive and generalized linear models, and estimated the percentage change of mortality rate associated with a 1°C increase of mean temperature. The temperature-responses for the hemorrhagic and ischemic stroke mortality differed, particularly in the range of high temperature. The estimated percentage change of ischemic stroke mortality above a threshold temperature was 5.4 % (95 % CI, 3.9-6.9 %) in Seoul, 4.1 % (95 % CI, 1.6-6.6 %) in Incheon, 2.3 % (-0.2 to 5.0 %) in Daegu and 3.6 % (0.7-6.6 %) in Busan, after controlling for daily mean humidity, mean air pressure, day of the week, season, and year. Additional adjustment of air pollution concentrations in the model did not change the effects. Hemorrhagic stroke mortality risk significantly decreased with increasing temperature without a threshold in the four cities after adjusting for confounders. These findings suggest that the mortality of hemorrhagic and ischemic strokes show different patterns in relation to outdoor temperature. High temperature was harmful for ischemic stroke but not for hemorrhagic stroke. The risk of high temperature to ischemic stroke did not differ by age or gender.

  17. Variation in mortality of ischemic and hemorrhagic strokes in relation to high temperature.

    PubMed

    Lim, Youn-Hee; Kim, Ho; Hong, Yun-Chul

    2013-01-01

    Outdoor temperature has been reported to have a significant influence on the seasonal variations of stroke mortality, but few studies have investigated the effect of high temperature on the mortality of ischemic and hemorrhagic strokes. The main study goal was to examine the effect of temperature, particularly high temperature, on ischemic and hemorrhagic strokes. We investigated the association between outdoor temperature and stroke mortality in four metropolitan cities in Korea during 1992-2007. We used time series analysis of the age-adjusted mortality rate for ischemic and hemorrhagic stroke deaths by using generalized additive and generalized linear models, and estimated the percentage change of mortality rate associated with a 1°C increase of mean temperature. The temperature-responses for the hemorrhagic and ischemic stroke mortality differed, particularly in the range of high temperature. The estimated percentage change of ischemic stroke mortality above a threshold temperature was 5.4 % (95 % CI, 3.9-6.9 %) in Seoul, 4.1 % (95 % CI, 1.6-6.6 %) in Incheon, 2.3 % (-0.2 to 5.0 %) in Daegu and 3.6 % (0.7-6.6 %) in Busan, after controlling for daily mean humidity, mean air pressure, day of the week, season, and year. Additional adjustment of air pollution concentrations in the model did not change the effects. Hemorrhagic stroke mortality risk significantly decreased with increasing temperature without a threshold in the four cities after adjusting for confounders. These findings suggest that the mortality of hemorrhagic and ischemic strokes show different patterns in relation to outdoor temperature. High temperature was harmful for ischemic stroke but not for hemorrhagic stroke. The risk of high temperature to ischemic stroke did not differ by age or gender.

  18. Temperature-dependent photoinduced third-harmonic-generation variation in azo-homopolymer and azo-doped polymer thin films

    NASA Astrophysics Data System (ADS)

    Hsu, Chia-Chen; Lin, Jian-Hung; Huang, Tzer-Hsiang; Harada, Kenji

    2003-04-01

    The temperature effect on the variation of photoinduced third-harmonic generation (THG) of an azo-polyurethane homopolymer and an azo guest-host polymer is studied at several different temperatures. At higher temperatures, both angular hole burning and molecule angular redistribution motions weaken, due to the decreases of cis-to-trans thermal relaxation time and the cis population and the increase of orientational diffusion coefficient. Smaller photoinduced THG variation is observed in both samples at higher temperatures. Results from the THG recovery experiment show that polyurethane homopolymer thin films pumped at a high temperature have the best photoinduced THG variation stability after turning off the pump beam.

  19. Global surface air temperature in 1995: Return to pre-Pinatubo level

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Ruedy, R.; Sato, M.; Reynolds, R.

    Global surface air temperature has increased about 0.5°C from the minimum of mid-1992, a year after the Mt. Pinatubo eruption. Both a land-based surface air temperature record and a land-marine temperature index place the meteorological year 1995 at approximately the same level as 1990, previously the warmest year in the period of instrumental data. As El Niño warming was small in 1995, the solar cycle near a minimum, and ozone depletion near record levels, the observed high temperature supports the contention of an underlying global warming trend. The pattern of Northern Hemisphere temperature change in recent decades appears to reflect a change of atmospheric dynamics.

  20. Dynamic topography, gravity and the role of lateral viscosity variations from inversion of global mantle flow

    NASA Astrophysics Data System (ADS)

    Yang, Ting; Gurnis, Michael

    2016-11-01

    Lateral viscosity variations (LVVs) in the mantle influence geodynamic processes and their surface expressions. With the observed long-wavelength geoid, free-air anomaly, gravity gradient in three directions and discrete, high-accuracy residual topography, we invert for depth- and temperature-dependent and tectonically regionalized mantle viscosity with a mantle flow model. The inversions suggest that long-wavelength gravitational and topographic signals are mainly controlled by the radial viscosity profile; the pre-Cambrian lithosphere viscosity is slightly (˜ one order of magnitude) higher than that of oceanic and Phanerozoic lithosphere; plate margins are substantially weaker than plate interiors; and viscosity has only a weak apparent, dependence on temperature, suggesting either a balancing between factors or a smoothing of actual higher amplitude, but short wavelength, LVVs. The predicted large-scale lithospheric stress regime (compression or extension) is consistent with the world stress map (thrust or normal faulting). Both recent compiled high-accuracy residual topography and the predicted dynamic topography yield ˜1 km amplitude long-wavelength dynamic topography, inconsistent with recent studies suggesting amplitudes of ˜100 to ˜500 m. Such studies use a constant, positive admittance (transfer function between topography and gravity), in contrast to the evidence which shows that the earth has a spatially and wavelength-dependent admittance, with large, negative admittances between ˜4000 and ˜104 km wavelengths.

  1. Time series modelling of global mean temperature for managerial decision-making.

    PubMed

    Romilly, Peter

    2005-07-01

    Climate change has important implications for business and economic activity. Effective management of climate change impacts will depend on the availability of accurate and cost-effective forecasts. This paper uses univariate time series techniques to model the properties of a global mean temperature dataset in order to develop a parsimonious forecasting model for managerial decision-making over the short-term horizon. Although the model is estimated on global temperature data, the methodology could also be applied to temperature data at more localised levels. The statistical techniques include seasonal and non-seasonal unit root testing with and without structural breaks, as well as ARIMA and GARCH modelling. A forecasting evaluation shows that the chosen model performs well against rival models. The estimation results confirm the findings of a number of previous studies, namely that global mean temperatures increased significantly throughout the 20th century. The use of GARCH modelling also shows the presence of volatility clustering in the temperature data, and a positive association between volatility and global mean temperature.

  2. Coral reef bleaching and sea surface temperature anomalies: 1991-1996 global patterns

    SciTech Connect

    Goreau, T.J.; Hayes, R.L.; Strong, A.

    1997-12-31

    Global spatio-temporal patterns of mass coral reef bleaching during the first half of the 1990s continued to show the strong temperature correlations which first became established in the 1980s. Satellite sea surface temperature data and field observations were used to track thermal bleaching events in real time. Most bleaching events followed warm season sea surface temperature anomalies of around +1 degree celsius above historical means. Global bleaching patterns appear to have been strongly affected by worldwide cooling which followed eruption of Mount Pinatubo in June 1991. High water temperatures and mass coral reef bleaching took place in the Caribbean, Indian Ocean, and South Pacific in 1991, but there were few thermal anomalies or bleaching events in 1992 and 1993, years which were markedly cooler worldwide. Following the settling of Mount Pinatubo aerosols and resumption of global warming trends, extensive ocean thermal hot spots and bleaching events resumed in the South Pacific, South Atlantic, and Indian Oceans in 1994. Bleaching again took place in hot spots in the Indian Ocean and Caribbean in 1995, and in the South Atlantic, Caribbean, South Pacific, North Pacific, and Persian Gulf in 1996. Coral reefs worldwide are now very close to their upper temperature tolerance limits. This sensitivity, and the fact that the warmest ecosystems have no source of immigrant species pre-adapted to warmer conditions, may make coral reef ecosystems the first to be severely impacted if global temperatures and sea levels remain at current values or increase further.

  3. Global patterns of large copy number variations in the human genome reveal complexity in chromosome organization.

    PubMed

    Veerappa, Avinash M; Suresh, Raviraj V; Vishweswaraiah, Sangeetha; Lingaiah, Kusuma; Murthy, Megha; Manjegowda, Dinesh S; Padakannaya, Prakash; Ramachandra, Nallur B

    2015-01-01

    Global patterns of copy number variations (CNVs) in chromosomes are required to understand the dynamics of genome organization and complexity. For this study, analysis was performed using the Affymetrix Genome-Wide Human SNP Array 6.0 chip and CytoScan High-Density arrays. We identified a total of 44 109 CNVs from 1715 genomes with a mean of 25 CNVs in an individual, which established the first drafts of population-specific CNV maps providing a rationale for prioritizing chromosomal regions. About 19 905 ancient CNVs were identified across all chromosomes and populations at varying frequencies. CNV count, and sometimes CNV size, contributed to the bulk CNV size of the chromosome. Population specific lengthening and shortening of chromosomal length was observed. Sex bias for CNV presence was largely dependent on ethnicity. Lower CNV inheritance rate was observed for India, compared to YRI and CEU. A total of 33 candidate CNV hotspots from 5382 copy number (CN) variable region (CNVR) clusters were identified. Population specific CNV distribution patterns in p and q arms disturbed the assumption that CNV counts in the p arm are less common compared to long arms, and the CNV occurrence and distribution in chromosomes is length independent. This study unraveled the force of independent evolutionary dynamics on genome organization and complexity across chromosomes and populations. PMID:26390810

  4. Beyond the 'east-west' dichotomy: Global variation in cultural models of selfhood.

    PubMed

    Vignoles, Vivian L; Owe, Ellinor; Becker, Maja; Smith, Peter B; Easterbrook, Matthew J; Brown, Rupert; González, Roberto; Didier, Nicolas; Carrasco, Diego; Cadena, Maria Paz; Lay, Siugmin; Schwartz, Seth J; Des Rosiers, Sabrina E; Villamar, Juan A; Gavreliuc, Alin; Zinkeng, Martina; Kreuzbauer, Robert; Baguma, Peter; Martin, Mariana; Tatarko, Alexander; Herman, Ginette; de Sauvage, Isabelle; Courtois, Marie; Garðarsdóttir, Ragna B; Harb, Charles; Schweiger Gallo, Inge; Prieto Gil, Paula; Lorente Clemares, Raquel; Campara, Gabriella; Nizharadze, George; Macapagal, Ma Elizabeth J; Jalal, Baland; Bourguignon, David; Zhang, Jianxin; Lv, Shaobo; Chybicka, Aneta; Yuki, Masaki; Zhang, Xiao; Espinosa, Agustín; Valk, Aune; Abuhamdeh, Sami; Amponsah, Benjamin; Özgen, Emre; Güner, E Ülkü; Yamakoğlu, Nil; Chobthamkit, Phatthanakit; Pyszczynski, Tom; Kesebir, Pelin; Vargas Trujillo, Elvia; Balanta, Paola; Cendales Ayala, Boris; Koller, Silvia H; Jaafar, Jas Laile; Gausel, Nicolay; Fischer, Ronald; Milfont, Taciano L; Kusdil, Ersin; Çağlar, Selinay; Aldhafri, Said; Ferreira, M Cristina; Mekonnen, Kassahun Habtamu; Wang, Qian; Fülöp, Márta; Torres, Ana; Camino, Leoncio; Lemos, Flávia Cristina Silveira; Fritsche, Immo; Möller, Bettina; Regalia, Camillo; Manzi, Claudia; Brambilla, Maria; Bond, Michael Harris

    2016-08-01

    Markus and Kitayama's (1991) theory of independent and interdependent self-construals had a major influence on social, personality, and developmental psychology by highlighting the role of culture in psychological processes. However, research has relied excessively on contrasts between North American and East Asian samples, and commonly used self-report measures of independence and interdependence frequently fail to show predicted cultural differences. We revisited the conceptualization and measurement of independent and interdependent self-construals in 2 large-scale multinational surveys, using improved methods for cross-cultural research. We developed (Study 1: N = 2924 students in 16 nations) and validated across cultures (Study 2: N = 7279 adults from 55 cultural groups in 33 nations) a new 7-dimensional model of self-reported ways of being independent or interdependent. Patterns of global variation support some of Markus and Kitayama's predictions, but a simple contrast between independence and interdependence does not adequately capture the diverse models of selfhood that prevail in different world regions. Cultural groups emphasize different ways of being both independent and interdependent, depending on individualism-collectivism, national socioeconomic development, and religious heritage. Our 7-dimensional model will allow future researchers to test more accurately the implications of cultural models of selfhood for psychological processes in diverse ecocultural contexts. (PsycINFO Database Record PMID:27359126

  5. Global variation in terrestrial conservation costs, conservation benefits, and unmet conservation needs

    PubMed Central

    Balmford, Andrew; Gaston, Kevin J.; Blyth, Simon; James, Alex; Kapos, Val

    2003-01-01

    Our ability to identify cost-efficient priorities for conserving biological diversity is limited by the scarcity of data on conservation costs, particularly at fine scales. Here we address this issue using data for 139 terrestrial programs worldwide. We find that the annual costs of effective field-based conservation vary enormously, across seven orders of magnitude, from <$0.1 to >$1,000,000 per km2. This variation can be closely predicted from positive associations between costs per unit area and an array of indices of local development. Corresponding measures of conservation benefit are limited but show opposing global trends, being higher in less developed parts of the world. The benefit-to-cost ratio of conservation is thus far greater in less developed regions, yet these are where the shortfall in current conservation spending is most marked. Substantially increased investment in tropical conservation is therefore urgently required if opportunities for cost-effective action are not to be missed. PMID:12552123

  6. Functional Impact of Global Rare Copy Number Variation in Autism Spectrum Disorder

    PubMed Central

    Pinto, Dalila; Pagnamenta, Alistair T.; Klei, Lambertus; Anney, Richard; Merico, Daniele; Regan, Regina; Conroy, Judith; Magalhaes, Tiago R.; Correia, Catarina; Abrahams, Brett S.; Almeida, Joana; Bacchelli, Elena; Bader, Gary D.; Bailey, Anthony J.; Baird, Gillian; Battaglia, Agatino; Berney, Tom; Bolshakova, Nadia; Bölte, Sven; Bolton, Patrick F.; Bourgeron, Thomas; Brennan, Sean; Brian, Jessica; Bryson, Susan E.; Carson, Andrew R.; Casallo, Guillermo; Casey, Jillian; Cochrane, Lynne; Corsello, Christina; Crawford, Emily L.; Crossett, Andrew; Dawson, Geraldine; de Jonge, Maretha; Delorme, Richard; Drmic, Irene; Duketis, Eftichia; Duque, Frederico; Estes, Annette; Farrar, Penny; Fernandez, Bridget A.; Filipa, Ana; Folstein, Susan E.; Fombonne, Eric; Freitag, Christine M.; Gilbert, John; Gillberg, Christopher; Glessner, Joseph T.; Goldberg, Jeremy; Green, Andrew; Green, Jonathan; Guter, Stephen J.; Hakonarson, Hakon; Heron, Elizabeth A.; Hill, Matthew; Holt, Richard; Howe, Jennifer L.; Hughes, Gillian; Hus, Vanessa; Igliozzi, Roberta; Kim, Cecilia; Klauck, Sabine M.; Kolevzon, Alexander; Korvatska, Olena; Kustanovich, Vlad; Lajonchere, Clara M.; Lamb, Janine A.; Laskawiec, Magdalena; Leboyer, Marion; Le Couteur, Ann; Leventhal, Bennett L.; Lionel, Anath C.; Liu, Xiao-Qing; Lord, Catherine; Lotspeich, Linda; Lund, Sabata C.; Maestrini, Elena; Mahoney, William; Mantoulan, Carine; Marshall, Christian R.; McConachie, Helen; McDougle, Christopher J.; McGrath, Jane; McMahon, William M.; Merikangas, Alison; Migita, Ohsuke; Minshew, Nancy J.; Mirza, Ghazala K.; Munson, Jeff; Nelson, Stanley F.; Noakes, Carolyn; Noor, Abdul; Nygren, Gudrun; Oliveira, Guiomar; Papanikolaou, Katerina; Parr, Jeremy R.; Parrini, Barbara; Paton, Tara; Pickles, Andrew; Pilorge, Marion; Piven, Joseph; Ponting, Chris P.; Posey, David J.; Poustka, Annemarie; Poustka, Fritz; Prasad, Aparna; Ragoussis, Jiannis; Renshaw, Katy; Rickaby, Jessica; Roberts, Wendy; Roeder, Kathryn; Roge, Bernadette; Rutter, Michael L.; Bierut, Laura J.; Rice, John P.; Consortium, SAGE; Salt, Jeff; Sansom, Katherine; Sato, Daisuke; Segurado, Ricardo; Senman, Lili; Shah, Naisha; Sheffield, Val C.; Soorya, Latha; Sousa, Inês; Stein, Olaf; Stoppioni, Vera; Strawbridge, Christina; Tancredi, Raffaella; Tansey, Katherine; Thiruvahindrapduram, Bhooma; Thompson, Ann P.; Thomson, Susanne; Tryfon, Ana; Tsiantis, John; Van Engeland, Herman; Vincent, John B.; Volkmar, Fred; Wallace, Simon; Wang, Kai; Wang, Zhouzhi; Wassink, Thomas H.; Webber, Caleb; Wing, Kirsty; Wittemeyer, Kerstin; Wood, Shawn; Wu, Jing; Yaspan, Brian L.; Zurawiecki, Danielle; Zwaigenbaum, Lonnie; Buxbaum, Joseph D.; Cantor, Rita M.; Cook, Edwin H.; Coon, Hilary; Cuccaro, Michael L.; Devlin, Bernie; Ennis, Sean; Gallagher, Louise; Geschwind, Daniel H.; Gill, Michael; Haines, Jonathan L.; Hallmayer, Joachim; Miller, Judith; Monaco, Anthony P.; Nurnberger, John I.; Paterson, Andrew D.; Pericak-Vance, Margaret A.; Schellenberg, Gerard D.; Szatmari, Peter; Vicente, Astrid M.; Vieland, Veronica J.; Wijsman, Ellen M.; Scherer, Stephen W.; Sutcliffe, James S.; Betancur, Catalina

    2010-01-01

    The autism spectrum disorders (ASDs) are a group of conditions characterized by impairments in reciprocal social interaction and communication, and the presence of restricted and repetitive behaviors1. Individuals with an ASD vary greatly in cognitive development, which can range from above average to intellectual disability (ID)2. While ASDs are known to be highly heritable (~90%)3, the underlying genetic determinants are still largely unknown. Here, we analyzed the genome-wide characteristics of rare (<1% frequency) copy number variation (CNV) in ASD using dense genotyping arrays. When comparing 996 ASD individuals of European ancestry to 1,287 matched controls, cases were found to carry a higher global burden of rare, genic CNVs (1.19 fold, P= 0.012), especially so for loci previously implicated in either ASD and/or intellectual disability (1.69 fold, P= 3.4×10−4). Among the CNVs, there were numerous de novo and inherited events, sometimes in combination in a given family, implicating many novel ASD genes like SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus. We also discovered an enrichment of CNVs disrupting functional gene-sets involved in cellular proliferation, projection and motility, and GTPase/Ras signaling. Our results reveal many new genetic and functional targets in ASD that may lead to final connected pathways. PMID:20531469

  7. Beyond the 'east-west' dichotomy: Global variation in cultural models of selfhood.

    PubMed

    Vignoles, Vivian L; Owe, Ellinor; Becker, Maja; Smith, Peter B; Easterbrook, Matthew J; Brown, Rupert; González, Roberto; Didier, Nicolas; Carrasco, Diego; Cadena, Maria Paz; Lay, Siugmin; Schwartz, Seth J; Des Rosiers, Sabrina E; Villamar, Juan A; Gavreliuc, Alin; Zinkeng, Martina; Kreuzbauer, Robert; Baguma, Peter; Martin, Mariana; Tatarko, Alexander; Herman, Ginette; de Sauvage, Isabelle; Courtois, Marie; Garðarsdóttir, Ragna B; Harb, Charles; Schweiger Gallo, Inge; Prieto Gil, Paula; Lorente Clemares, Raquel; Campara, Gabriella; Nizharadze, George; Macapagal, Ma Elizabeth J; Jalal, Baland; Bourguignon, David; Zhang, Jianxin; Lv, Shaobo; Chybicka, Aneta; Yuki, Masaki; Zhang, Xiao; Espinosa, Agustín; Valk, Aune; Abuhamdeh, Sami; Amponsah, Benjamin; Özgen, Emre; Güner, E Ülkü; Yamakoğlu, Nil; Chobthamkit, Phatthanakit; Pyszczynski, Tom; Kesebir, Pelin; Vargas Trujillo, Elvia; Balanta, Paola; Cendales Ayala, Boris; Koller, Silvia H; Jaafar, Jas Laile; Gausel, Nicolay; Fischer, Ronald; Milfont, Taciano L; Kusdil, Ersin; Çağlar, Selinay; Aldhafri, Said; Ferreira, M Cristina; Mekonnen, Kassahun Habtamu; Wang, Qian; Fülöp, Márta; Torres, Ana; Camino, Leoncio; Lemos, Flávia Cristina Silveira; Fritsche, Immo; Möller, Bettina; Regalia, Camillo; Manzi, Claudia; Brambilla, Maria; Bond, Michael Harris

    2016-08-01

    Markus and Kitayama's (1991) theory of independent and interdependent self-construals had a major influence on social, personality, and developmental psychology by highlighting the role of culture in psychological processes. However, research has relied excessively on contrasts between North American and East Asian samples, and commonly used self-report measures of independence and interdependence frequently fail to show predicted cultural differences. We revisited the conceptualization and measurement of independent and interdependent self-construals in 2 large-scale multinational surveys, using improved methods for cross-cultural research. We developed (Study 1: N = 2924 students in 16 nations) and validated across cultures (Study 2: N = 7279 adults from 55 cultural groups in 33 nations) a new 7-dimensional model of self-reported ways of being independent or interdependent. Patterns of global variation support some of Markus and Kitayama's predictions, but a simple contrast between independence and interdependence does not adequately capture the diverse models of selfhood that prevail in different world regions. Cultural groups emphasize different ways of being both independent and interdependent, depending on individualism-collectivism, national socioeconomic development, and religious heritage. Our 7-dimensional model will allow future researchers to test more accurately the implications of cultural models of selfhood for psychological processes in diverse ecocultural contexts. (PsycINFO Database Record

  8. High-resolution mycorrhizal hyphae dynamics: temporal variation, biophysical controls, and global environmental change

    NASA Astrophysics Data System (ADS)

    Hernandez, R. R.; Allen, M. F.

    2010-12-01

    Soils are the largest terrestrial carbon (C) repository in the global C cycle, storing 4.5 times more C than aboveground vegetation. Mycorrhizal fungi are critical edaphic organisms that influence soil C dynamics at both microscopic and ecosystem scales. Understanding the production and turnover of these organisms is critical for accurate ecosystem C budgets and predictive models incorporating changes in climate. This study seeks to quantify high-resolution mycorrhizal hyphae dynamics at various temporal scales in a mixed conifer forest (UC James Reserve, CA) using novel technologies including automated minirhizotrons, embedded soil sensor networks, and environmental software (i.e., Rootfly). We found that hyphae elongation and dieback rates in May 2009 varied significantly across 6-h diel time intervals and were greatest between 12:00 pm and 6:00 pm, when soil temperature and modeled CO2 flux is maximum. Seasonal dynamics revealed peak hyphae biomass in mid-April and rapid hyphae length decline from mid-April through June. Seasonal hyphae dynamism is tightly coupled with biophysical controls, namely, soil water content, which is positively related to hyphae production, and soil temperature. Interestingly, 14 °C may be a threshold for hyphae growth in this system as soil temperatures exceeding this value are coupled with rapid hyphae mortality. This study suggests that human-mediated changes to biophysical controls may modulate seasonal hyphae growth regimes, possibly reducing growth season duration or initiating early mortality. In this scenario, mycorrhizal hyphae mortality may act as a positive feedback to increasing CO2 levels, by releasing large amounts of CO2 into the atmosphere.

  9. SABER (TIMED) and MLS (UARS) Temperature Observations of Mesospheric and Stratospheric QBO and Related Tidal Variations

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans G.; Reber, Carl A.; Russell, James; Mlynczak, Marty; Mengel, John

    2006-01-01

    More than three years of temperature observations from the SABER (TIMED) and MLS WARS) instruments are analyzed to study the annual and inter-annual variations extending from the stratosphere into the upper mesosphere. The SABER measurements provide data from a wide altitude range (15 to 95 km) for the years 2002 to 2004, while the MLS data were taken in the 16 to 55 km altitude range a decade earlier. Because of the sampling properties of SABER and MLS, the variations with local solar time must be accounted for when estimating the zonal mean variations. An algorithm is thus applied that delineates with Fourier analysis the year-long variations of the migrating tides and zonal mean component. The amplitude of the diurnal tide near the equator shows a strong semiannual periodicity with maxima near equinox, which vary from year to year to indicate the influence from the Quasi-biennial Oscillation (QBO) in the zonal circulation. The zonal mean QBO temperature variations are analyzed over a range of latitudes and altitudes, and the results are presented for latitudes from 48"s to 48"N. New results are obtained for the QBO, especially in the upper stratosphere and mesosphere, and at mid-latitudes. At Equatorial latitudes, the QBO amplitudes show local peaks, albeit small, that occur at different altitudes. From about 20 to 40 km, and within about 15" of the Equator, the amplitudes can approach 3S K for the stratospheric QBO or SQBO. For the mesospheric QBO or MQBO, we find peaks near 70 km, with temperature amplitudes reaching 3.5"K, and near 85 km, the amplitudes approach 2.5OK. Morphologically, the amplitude and phase variations derived from the SABER and MLS measurements are in qualitative agreement. The QBO amplitudes tend to peak at the Equator but then increase again pole-ward of about 15" to 20'. The phase progression with altitude varies more gradually at the Equator than at mid-latitudes. A comparison of the observations with results from the Numerical Spectral

  10. Temperature and humidity control during cooling and dehumidifying by compressor and evaporator fan speed variation

    SciTech Connect

    Krakow, K.I.; Lin, S.; Zeng, Z.S.

    1995-08-01

    The accurate control of temperature and relative humidity during cooling and dehumidifying air-conditioning processes may be achieved by compressor and evaporator fan speed variation. Proportional-integral-differential (PID) control methods are shown to be suitable for attaining compressor and evaporator fan speeds such that the sensible and latent components of the refrigeration system capacity equal the sensible and latent components of the system load. The feasibility of the control method has been verified experimentally. A numerical model of an environmental control system, including refrigeration, space, and PID control subsystems, has been developed. The model is suitable for determining system response to variations of PID coefficient values and to variations of system loads.

  11. An in vivo recording of variations in oral temperature during meals: a pilot study.

    PubMed

    Michailesco, P M; Marciano, J; Grieve, A R; Abadie, M J

    1995-02-01

    Thermocycling is often used in the in vitro evaluation of marginal leakage of dental restorations. The in vivo temperatures occurring during meals were recorded at different surfaces of restored teeth, to compare the variations in temperature with laboratory thermocycling. Temperatures were recorded with thermocouples at three different sites: (1) on the facial surface of a silver amalgam restoration, (2) at the base of a silver amalgam restoration and (3) within the root canal. The maximal temperature differences between upper and lower extremes were 29.6 degrees C at the base of a coronal restoration, 27.1 degrees C at the facial surface, and 11.8 degrees C within the root canal. A practical regimen for these experiments is suggested in the light of these ranges because many thermocycling regimens in in vitro studies appear extreme or unrealistic.

  12. Analysis of Variation of Piston Temperature with Piston Dimensions and Undercrown Cooling

    NASA Technical Reports Server (NTRS)

    Sanders, J C; Schramm, W B

    1948-01-01

    A theoretical analysis is presented that permits estimation of the changes in piston-temperature distribution induced by variations in the crown thickness, the ring-groove-pad thickness, and the undercrown surface heat-transfer coefficient. The analysis consists of the calculation of operating temperatures at various points in the piston body on the basis of the experimentally determined surface heat-transfer coefficients and boundary-region temperatures, as well as arbitrarily selected surface coefficients. Surface heat-transfer coefficients were estimated from the internal temperature gradients obtained by hardness surveys of aluminum pistons that had been operated under severe conditions in a liquid-cooled, single-cylinder, 5 1/2 by 6-inch test engine.

  13. Analysis of stream-temperature variations in the Upper Delaware River Basin, New York

    USGS Publications Warehouse

    Williams, Owen O.

    1971-01-01

    The effect of climatologic conditions and reservoir releases on downstream conditions was determined by means of statistical and graphical analyses of stream-temperature variations measured in the upper Delaware River basin, May-September 1964-67. Climatologic conditions normally increase water temperatures from February through July and decrease them from August through January. Summer releases from New York City's Cannonsville Reservoir were observed to decrease water temperatures by 13?C (Celsius) in 8.1 miles and by 1?C, 55.9 miles downstream from this reservoir. Releases from New York City's Pepacton Reservoir were observed to decrease water temperatures by 11?C in 31.0 miles and between 1?-3?C in 71.0 miles downstream from this reservoir. The influence of releases from these reservoirs is dependent upon five factors: thermal stratification in the reservoir, depth at which water is withdrawn from the reservoir, rate of release, distance downstream from the reservoir, and climatologic conditions.

  14. Global and Regional Temperature-change Potentials for Near-term Climate Forcers

    NASA Technical Reports Server (NTRS)

    Collins, W.J.; Fry, M.M.; Yu, H.; Fuglestvedt, J. S.; Shindell, D. T.; West, J. J.

    2013-01-01

    We examine the climate effects of the emissions of near-term climate forcers (NTCFs) from 4 continental regions (East Asia, Europe, North America and South Asia) using results from the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model simulations. We address 3 aerosol species (sulphate, particulate organic matter and black carbon) and 4 ozone precursors (methane, reactive nitrogen oxides (NOx), volatile organic compounds and carbon monoxide). We calculate the global climate metrics: global warming potentials (GWPs) and global temperature change potentials (GTPs). For the aerosols these metrics are simply time-dependent scalings of the equilibrium radiative forcings. The GTPs decrease more rapidly with time than the GWPs. The aerosol forcings and hence climate metrics have only a modest dependence on emission region. The metrics for ozone precursors include the effects on the methane lifetime. The impacts via methane are particularly important for the 20 yr GTPs. Emissions of NOx and VOCs from South Asia have GWPs and GTPs of higher magnitude than from the other Northern Hemisphere regions. The analysis is further extended by examining the temperature-change impacts in 4 latitude bands, and calculating absolute regional temperature-change potentials (ARTPs). The latitudinal pattern of the temperature response does not directly follow the pattern of the diagnosed radiative forcing. We find that temperatures in the Arctic latitudes appear to be particularly sensitive to BC emissions from South Asia. The northern mid-latitude temperature response to northern mid-latitude emissions is approximately twice as large as the global average response for aerosol emission, and about 20-30% larger than the global average for methane, VOC and CO emissions.

  15. Weekend effect of temperature variation in the Yangtze River delta of China

    NASA Astrophysics Data System (ADS)

    Ma, Li; Jiang, Zhihong; Duan, Chunfeng; Miao, Qilong; Wang, Yong

    2009-03-01

    Study is performed of the weekly cycle of temperature indices (its diurnal range, mean, maximum and minimum) as well as cloudiness, solar radiation and air pollution index based on 1996-2005 surface observations and air pollution indexes from four big cities over the Yangtze River Delta of China. Results suggest that these temperature variations are featured by significant weekend effect (WE) in that these temperatures are higher at weekends than on workdays in summer as opposed to those in other seasons; the WE of diurnal maximum and minimum temperatures is much bigger at weekends and can be utilized as the WE index; during the long spell of holidays or festivities in China WE is remarkable, and especially in the Spring Festival and National Day holidays these temperatures are smaller compared to those 7 day before and after as opposed to the values during, and 7 days before/after, the May Day holidays; the temperature WE bears a close relation to aerosol concentration thanks to anthropogenic activities; in summer the indirect impacts of aerosols (aerosol - cloud interactions) due to abundant vapor play a dominant role and at weekends little aerosol is responsible for reduced cloudiness, allowing more solar radiation to strike the ground for the rise in all the temperatures; in the other seasons the direct and semi-direct effect of aerosol plays a predominant part, with the concentration of aerosols declining at weekends for reducing its ability to heat air and increasing cloudiness, thus leading to the decrease in all the temperature elements.

  16. Investigation of photospheric temperature gradient variations using limb darkening measurements and simulations

    NASA Astrophysics Data System (ADS)

    Criscuoli, Serena; Foukal, Peter V.

    2016-05-01

    The temperature stratifications of magnetic elements and unmagnetized plasma are different, so that changes of the facular and network filling factor over the cycle modify the average temperature gradient in the photosphere.Such variations have been suggested to explain irradiance measurements obtained by the SIM spectrometers in he visible and infrared spectral ranges. On the other hand, limb darkening measurements show no dependence upon activity level. We investigate the sensitivity of limb darkening to changes in network area filling factor using a 3-D MHD model of the magnetized photosphere. We find that the expected limb darkening change due to the measured 11- yr variation in filling factor lies outside the formal 99% confidence limit of the limb darkening measurements. This poses important constraints for observational validation of 3D-MHD simulations.

  17. Variation of transition temperatures and residual resistivity ratio in vapor-grown FeSe

    DOE PAGESBeta

    Böhmer, A. E.; Taufour, V.; Straszheim, W. E.; Wolf, T.; Canfield, P. C.

    2016-07-29

    The study of the iron-based superconductor FeSe has blossomed with the availability of high-quality single crystals, obtained through flux/vapor-transport growth techniques below the structural transformation temperature of its tetragonal phase, T≈450°C. Here, we report on the variation of sample morphology and properties due to small modifications in the growth conditions. A considerable variation of the superconducting transition temperature Tc, from 8.8 K to 3 K, which cannot be correlated with the sample composition, is observed. Instead, we point out a clear correlation between Tc and disorder, as measured by the residual resistivity ratio. Notably, the tetragonal-to-orthorhombic structural transition is alsomore » found to be quite strongly disorder dependent (Ts≈72–90K) and linearly correlated with Tc.« less

  18. Variation of wave velocity and porosity of sandstone after high temperature heating

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Zhang, ·Weiqiang; Su, Tianming; Zhu, Shuyun

    2016-05-01

    This paper reports the variations of mass, porosity, and wave velocity of sandstone after high temperature heating. The range of temperature to which the sandstone specimens have been exposed is 25-850°C, in a heating furnace. It has been shown that below 300°C, porosity and wave velocity change very little. Above 300°C, there is a rapid increase in porosity, but the wave velocity decreases significantly. The results of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) suggest that a series of changes occurred between 400 and 600°C in sandstone could be responsible for the different patterns of variation in porosity and wave velocity.

  19. Vertical variations of charged-particle temperature and density in quiet conditions

    NASA Astrophysics Data System (ADS)

    Apati, I.; Semerei, T.; Afonin, V.; Bezrukikh, V.; Shiutte, N.; Bentse, P.

    1983-09-01

    Electrostatic analyzers aboard the Vertical-6 rocket were used to study vertical variations of charged-particle temperature and density at heights of 200-1200 km during quiet-solar conditions on October 25, 1977. The heating of the electron-ion gas was found to have an essentially nonmonotonic character. Above the F-region maximum, significant fluctuations of ion-gas temperature were observed, apparently associated with vertical variations of cooling and heating due to the excitation of the fine structure of atomic-oxygen levels as well as due to the effect of ion-exchange reactions. The maximum heating of ion gas occurs at heights where hydrogen ions begin to predominate. It is noted that the results obtained can be used to improve existing ionospheric models relating to periods of low solar activity.

  20. Multigrid Solution of the Navier-Stokes Equations at Low Speeds with Large Temperature Variations

    NASA Technical Reports Server (NTRS)

    Sockol, Peter M.

    2002-01-01

    Multigrid methods for the Navier-Stokes equations at low speeds and large temperature variations are investigated. The compressible equations with time-derivative preconditioning and preconditioned flux-difference splitting of the inviscid terms are used. Three implicit smoothers have been incorporated into a common multigrid procedure. Both full coarsening and semi-coarsening with directional fine-grid defect correction have been studied. The resulting methods have been tested on four 2D laminar problems over a range of Reynolds numbers on both uniform and highly stretched grids. Two of the three methods show efficient and robust performance over the entire range of conditions. In addition none of the methods have any difficulty with the large temperature variations.

  1. Birefringence Variation With High Pressure And Temperature In Elliptical Core Single Mode Fiber.

    NASA Astrophysics Data System (ADS)

    Domanski, Andrzej W.; Bock, Wojtek J.

    1990-01-01

    High - birefringent optical fiber with elliptical core was placed inside a high pressure and temperature controlled measuring chamber equipped with special fiber optic leadthrough system. The experiments were carried out in University of Quebec at Hull Optoelectronics Laboratory by using Harwood DWT-35 dead weight tester as a pressure standard up to 100MPa. Linearly polarised light was injected into fiber. Then changes in polarisation state of light passed through the fiber in term of hydrostatic pressure and temperature variation were filvestigated. Birefringence variations were determined by measurements of changes in beat length ofthe siagle mode elliptical core fiber. The fiber was prepared in laboratories of Maria Curie University at Lublin. Based on the results obtained we could determined hydrostatic pressure of compensation of intrinsic stress i.e. ,the pressure for which birefringence is diminished to zero.

  2. Temperature Variations of Saturn Rings with Viewing Geometries from Prime to Equinox Cassini Missions

    NASA Technical Reports Server (NTRS)

    Deau, E. A.; Spilker, L. J.; Morishima, R.; Brooks, S.; Pilorz, S.; Altobelli, N.

    2011-01-01

    After more than six years in orbit around Saturn, the Cassini Composite Infrared Spectrometer (CIRS) has acquired an extensive set of measurements of Saturn's main rings (A, B, C and Cassini Division) in the thermal infrared. Temperatures were retrieved for the lit and unlit rings over a variety of ring geometries that include phase angle, solar and spacecraft elevations and local time. We show that some of these parameters (solar and spacecraft elevations, phase angle) play a role in the temperature variations in the first order, while the others (ring and particle local time) produced second order effects. The results of this comparison will be presented.

  3. Anaerobic treatment of urban wastewater in membrane bioreactors: evaluation of seasonal temperature variations.

    PubMed

    Giménez, J B; Martí, N; Robles, A; Ferrer, J; Seco, A

    2014-01-01

    The objective of this study was to evaluate the effect of seasonal temperature variations on the anaerobic treatment of urban wastewater in membrane bioreactors (MBRs). To this aim, sludge production, energy recovery potential, chemical oxygen demand (COD) removal and membrane permeability were evaluated in a submerged anaerobic MBR fitted with industrial-scale membrane units. The plant was operated for 172 days, between summer and winter seasons. Sludge production increased and energy recovery potential decreased when temperature decreased. COD removal and membrane permeability remained nearby stable throughout the whole experimental period.

  4. Characterization of elastic-plastic behavior of AS4/PEEK thermoplastic composite for temperature variation

    NASA Technical Reports Server (NTRS)

    Sun, C. T.; Yoon, K. J.

    1991-01-01

    Inelastic and strength properties of AS4/PEEK composites were characterized with respect to temperature variation by using a one-parameter orthotropic plasticity model and a one-parameter failure criterion. Simple uniaxial off-axis tension tests were performed on coupon specimens of unidirectional AS4/PEEK thermoplastic composite at various temperatures. To avoid the complication caused by the extension-shear coupling effect in off-axis testing, new tabs were designed and used on the test specimens. Experimental results showed that the nonlinear behavior of constitutive relations and the strength can be characterized quite well using the one-parameter plasticity model and the failure criterion, respectively.

  5. Analysis of Long-Term Temperature Variations in the Human Body.

    PubMed

    Dakappa, Pradeepa Hoskeri; Mahabala, Chakrapani

    2015-01-01

    Body temperature is a continuous physiological variable. In normal healthy adults, oral temperature is estimated to vary between 36.1°C and 37.2°C. Fever is a complex host response to many external and internal agents and is a potential contributor to many clinical conditions. Despite being one of the foremost vital signs, temperature and its analysis and variations during many pathological conditions has yet to be examined in detail using mathematical techniques. Classical fever patterns based on recordings obtained every 8-12 h have been developed. However, such patterns do not provide meaningful information in diagnosing diseases. Because fever is a host response, it is likely that there could be a unique response to specific etiologies. Continuous long-term temperature monitoring and pattern analysis using specific analytical methods developed in engineering and physics could aid in revealing unique fever responses of hosts and in different clinical conditions. Furthermore, such analysis can potentially be used as a novel diagnostic tool and to study the effect of pharmaceutical agents and other therapeutic protocols. Thus, the goal of our article is to present a comprehensive review of the recent relevant literature and analyze the current state of research regarding temperature variations in the human body.

  6. Annual variation in temperature and composition of the thermosphere and upper mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Harris, I.

    1977-01-01

    A three-dimensional circulation model, including UV (O2 dissociation) and EUV sources, is used to study the wind field and the effects of temperature and composition on annual thermospheric variations. The results are compared to those of OGO-6 and AE-C. Within an 800-1200 K temperature range, summer to winter temperature variation is studied as a function of solar activity. It is found that the model correctly predicts H, He, O, N2, O2, and Ar measurements. It is suggested that a small winter maximum in mesospheric temperature is caused by large-scale circulation induced by EUV heating. This effect, however, is masked by the energy released in O2 dissociation. The annual temperature amplitude and the winter oxygen bulge are noted to increase with increasing solar activity, whereas the winter helium bulge is noted to decrease with enhanced exospheric return flow. It is felt that the dependence of the F2 region winter anomaly on solar activity may be significantly affected by the solar activity effect in atomic oxygen.

  7. Temperature is the key to altitudinal variation of phenolics in Arnica montana L. cv. ARBO.

    PubMed

    Albert, Andreas; Sareedenchai, Vipaporn; Heller, Werner; Seidlitz, Harald K; Zidorn, Christian

    2009-05-01

    Plants in alpine habitats are exposed to many environmental stresses, in particular temperature and radiation extremes. Recent field experiments on Arnica montana L. cv. ARBO indicated pronounced altitudinal variation in plant phenolics. Ortho-diphenolics increased with altitude compared to other phenolic compounds, resulting in an increase in antioxidative capacity of the tissues involved. Factors causing these variations were investigated by climate chamber (CC) experiments focusing on temperature and ultraviolet (UV)-B radiation. Plants of A. montana L. cv. ARBO were grown in CCs under realistic climatic and radiation regimes. Key factors temperature and UV-B radiation were altered between different groups of plants. Subsequently, flowering heads were analyzed by HPLC for their contents of flavonoids and caffeic acid derivatives. Surprisingly, increased UV-B radiation did not trigger any change in phenolic metabolites in Arnica. In contrast, a pronounced increase in the ratio of B-ring ortho-diphenolic (quercetin) compared to B-ring monophenolic (kaempferol) flavonols resulted from a decrease in temperature by 5 degrees C in the applied climate regime. In conclusion, enhanced UV-B radiation is probably not the key factor triggering shifts in the phenolic composition in Arnica grown at higher altitudes but rather temperature, which decreases with altitude.

  8. Phenophysiological variation of a bee that regulates hive humidity, but not hive temperature.

    PubMed

    Ayton, Sasha; Tomlinson, Sean; Phillips, Ryan D; Dixon, Kingsley W; Withers, Philip C

    2016-05-15

    Seasonal acclimatisation of thermal tolerance, evaporative water loss and metabolic rate, along with regulation of the hive environment, are key ways whereby hive-based social insects mediate climatic challenges throughout the year, but the relative importance of these traits remains poorly understood. Here, we examined seasonal variation in metabolic rate and evaporative water loss of worker bees, and seasonal variation of hive temperature and relative humidity (RH), for the stingless bee Austroplebeia essingtoni (Apidae: Meliponini) in arid tropical Australia. Both water loss and metabolic rate were lower in the cooler, dry winter than in the hot, wet summer at most ambient temperatures between 20°C and 45°C. Contrary to expectation, thermal tolerance thresholds were higher in the winter than in the summer. Hives were cooler in the cooler, dry winter than in the hot, wet summer, linked to an apparent lack of hive thermoregulation. The RH of hives was regulated at approximately 65% in both seasons, which is higher than unoccupied control hives in the dry season, but less than unoccupied control hives in the wet season. Although adaptations to promote water balance appear more important for survival of A. essingtoni than traits related to temperature regulation, their capacity for water conservation is coincident with increased thermal tolerance. For these small, eusocial stingless bees in the arid tropics, where air temperatures are relatively high and stable compared with temperate areas, regulation of hive humidity appears to be of more importance than temperature for maintaining hive health. PMID:26994173

  9. Geographic Variation in the Diet of Opaleye (Girella nigricans) with Respect to Temperature and Habitat

    PubMed Central

    Behrens, Michael D.; Lafferty, Kevin D.

    2012-01-01

    We studied diet variation in an omnivorous fish across its range, which allowed us to test predictions about the effect of ocean temperature and habitat on herbivory. Throughout most of its geographic range, from Southern California to central Baja California, the opaleye (Girella nigricans) fed primarily on red and green algae, but there was significant variation in the amount of algal material in the diet among sites. The proportion of algal material in the diet was related to habitat, with algae making up a larger proportion of a fish’s diet in algal-dominated habitats than in urchin barrens. Independent of habitat, the proportion of algal material in the diet increased with environmental temperature. Analyses of stable isotopes revealed similar changes in trophic position and confirmed that these associations with diet persisted over relatively long time scales. The shift to a more herbivorous diet at warmer temperatures is in agreement with past laboratory studies on this species that show a diet-dependent change in performance with temperature and can indicate a diet shift across the species’ geographic range to meet its physiological demands. A possible plastic response to herbivory was a longer gut relative to body size. The results of this study are consistent with past findings that associate temperature with increases in the relative diversity of herbivorous fishes in tropical parts of the ocean. PMID:23029302

  10. Influence of variations in extratropical wintertime teleconnections on Northern Hemisphere temperature

    SciTech Connect

    Hurrell, J.W.

    1996-03-15

    Pronounced changes in the wintertime atmospheric circulation have occurred since the mid-1970s over the ocean basins of the Northern Hemisphere, and these changes have had a profound effect on surface temperatures. The variations over the North Atlantic are related to changes in the North Atlantic Oscillation (NAO), while the changes over the North Pacific are linked to the tropics and involve variations in the Aleutian low with teleconnections downstream over North America. Multivariate linear regression is used to show that nearly all of the cooling in the northwest Atlantic and the warming across Europe and downstream over Eurasia since the mid-1970s results from the changes in the NAO, and the NAO accounts for 31% of the hemispheric interannual variance over the past 60 winters. Over the Pacific basin and North America, the temperature anomalies result in part from tropical forcing associated with the El Nino-Southern Oscillation phenomenon but with important feedbacks in the extratropics. The changes in circulation over the past two decades have resulted in a surface temperature anomaly pattern of warmth over the continents and coolness over the oceans. This pattern of temperature change has amplified the observed hemispheric-averaged warming because of it interaction with land and ocean; temperature changes are larger over land compared to the oceans because of the small heat capacity of the former. 13 refs., 5 fig., 2 tab.

  11. Variation in photosynthetic response to temperature in a guild of winter annual plants.

    PubMed

    Gremer, Jennifer R; Kimball, Sarah; Angert, Amy L; Venable, D Lawrence; Huxman, Travis E

    2012-12-01

    How species respond to environmental variation can have important consequences for population and community dynamics. Temperature, in particular, is one source of variation expected to strongly influence plant performance. Here, we compared photosynthetic responses to temperature across a guild of winter annual plants. Previous work in this system identified a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) that predicts species differences in population dynamics over time, which then contribute to long-term species coexistence. Interestingly, species with high WUE invest in photosynthetic processes that appear to maximize carbon assimilation, while high-RGR species appear to maximize carbon gain by increasing leaf area for photosynthesis. In high-WUE species, higher rates of carbon acquisition were associated with increased investment into light-driven electron transport (J(max)). We tested whether such allocation allows these plants to have greater photosynthetic performance at lower temperatures by comparing the temperature sensitivity of photosynthesis across species in the community. Six species were grown in buried pots in the field, allowing them to experience natural changes in seasonal temperature. Plants were taken from the field and placed in growth chambers where photosynthetic performance was measured following short-term exposure to a wide range of temperatures. These measurements were repeated throughout the season. Our results suggest that high-WUE species are more efficient at processing incoming light, as measured by chlorophyll fluorescence, and exhibit higher net photosynthetic rates (A(net)) than high-RGR species, and these advantages are greatest at low temperatures. Sampling date differentially affected fluorescence across species, while species had similar seasonal changes in A(net). Our results suggest that species-specific responses to temperature contribute to the WUE-RGR trade-off that has been shown to

  12. Seasonal Variations in Titan's Stratosphere Observed with Cassini/CIRS: Temperature, Trace Molecular Gas and Aerosol Mixing Ratio Profiles

    NASA Technical Reports Server (NTRS)

    Vinatier, S.; Bezard, B.; Anderson, C. M.; Coustenis, A.; Teanby, N.

    2012-01-01

    Titan's northern spring equinox occurred in August 2009. General Circulation Models (e.g. Lebonnois et al., 2012) predict strong modifications of the global circulation in this period, with formation of two circulation cells instead of the pole-to-pole cell that occurred during northern winter. This winter single cell, which had its descending branch at the north pole, was at the origin of the enrichment of molecular abundances and high stratopause temperatures observed by Cassini/CIRS at high northern latitudes (e.g. Achterberg et al., 2011, Coustenis et al., 2010, Teanby et al., 2008, Vinatier et al., 2010). The predicted dynamical seasonal variations after the equinox have strong impact on the spatial distributions of trace gas, temperature and aerosol abundances. We will present here an analysis of CIRS limb-geometry datasets acquired in 2010 and 2011 that we used to monitor the seasonal evolution of the vertical profiles of temperature, molecular (C2H2, C2H6, HCN, ..) and aerosol abundances.

  13. Projected Increase in Diurnal and Inter-Diurnal Variations of European Summer Temperatures

    NASA Astrophysics Data System (ADS)

    Cattiaux, J.; Douville, H.; Schoetter, R.; Parey, S.; Yiou, P.

    2014-12-01

    The current European warming is expected to be associated with an increased temperature variability in summer, particularly at the daily time-scale. Such an increase would affect hot extremes and accentuate the societal and environmental impacts caused by the mean warming. Here we investigate future changes in the short-term variability of European summer temperatures using two indices that have been seldom documented so far: the variations within one day (diurnal temperature range, DTR) and the variations from one day to the next (inter-diurnal temperature variability, ITV). These rapid variations represent key issues for impact communities, in particular energy providers vulnerable to sudden surges in electricity demand. Besides, the ITV provides a measure of daily variability that is not disturbed by longer-term variations in the mean (e.g., seasonal cycle and/or a multi-year trend), whereas traditional measures such as standard deviation or variance are. We use 21st-century projections performed by 34 models of the CMIP5 ensemble under the three RCP 2.6, 4.5 and 8.5 scenarios. Models are evaluated over the present-day period against the E-OBS dataset. In Europe, both indices of summer temperature variability are projected to increase, with a rather good model agreement on the sign, while uncertainties remain on the amplitude. In particular, we show that extremely high day-to-day and/or diurnal temperature variations are expected to occur more frequently. We highlight the singularity of the European area, since ITV and DTR changes do not systematically coincide over other regions (e.g., the U.S). Then we investigate the physical processes underlying these ITV and DTR changes in the CMIP5 projections. The respective contributions of the summer drying of European soils, the reduction in cloud cover and the changes in large-scale dynamics are estimated. Finally, the possibility of reducing model uncertainties through constraints emerging from both present

  14. Flight summaries and temperature climatology at airliner cruise altitudes from GASP (Global Atmospheric Sampling Program) data

    NASA Technical Reports Server (NTRS)

    Nastrom, G. D.; Jasperson, W. H.

    1983-01-01

    Temperature data obtained by the Global Atmospheric Sampling Program (GASP) during the period March 1975 to July 1979 are compiled to form flight summaries of static air temperature and a geographic temperature climatology. The flight summaries include the height and location of the coldest observed temperature and the mean flight level, temperature and the standard deviation of temperature for each flight as well as for flight segments. These summaries are ordered by route and month. The temperature climatology was computed for all statistically independent temperture data for each flight. The grid used consists of 5 deg latitude, 30 deg longitude and 2000 feet vertical resolution from FL270 to FL430 for each month of the year. The number of statistically independent observations, their mean, standard deviation and the empirical 98, 50, 16, 2 and .3 probability percentiles are presented.