Science.gov

Sample records for 20th-century climate simulations

  1. Inconsistencies and Fallacies: IPCC 20th Century Simulations, Multi-Model Ensembles and Climate Sensitivity

    NASA Astrophysics Data System (ADS)

    Rogers, N. L.

    2009-12-01

    The IPCC used an experiment that had approximately 20 different climate models fit the temperature history of the 20th century. A remarkably good and convincing fit was obtained by combining selected models into a multi-model ensemble. This may be seen in figure 9.5 of the AR4 Scientific Basis report. The fallacy is that each modeling group used different forcings, effectively simulating a different imaginary planet. Since the IPCC models differ by more than 2-1 in climate sensitivity it would be quite amazing if they could all agree on temperature in the late 20th century when CO2 was rapidly increasing. Allowing each model to be excited by different forcings effectively makes the model be a rather complicated curve fitting program. If one accepts that the models are being used to do curve fitting then the supposedly better results obtained by averaging multiple models is easily explainable as the reduction of error that results from averaging approximations to a function with uncorrelated errors. Finally the late 20th century temperature rise is too small for a 3 degree climate sensitivity for doubling of CO2 and the explanations for the warming shortfall that rely on aerosol cooling or ocean warming are easily refuted.There may be alternative explanations for the shortfall or it may be that climate sensitivity is much lower than projected by the IPCC.

  2. A time-series analysis of the 20th century climate simulations produced for the IPCC's Fourth Assessment Report.

    PubMed

    Estrada, Francisco; Perron, Pierre; Gay-García, Carlos; Martínez-López, Benjamín

    2013-01-01

    In this paper evidence of anthropogenic influence over the warming of the 20th century is presented and the debate regarding the time-series properties of global temperatures is addressed in depth. The 20th century global temperature simulations produced for the Intergovernmental Panel on Climate Change's Fourth Assessment Report and a set of the radiative forcing series used to drive them are analyzed using modern econometric techniques. Results show that both temperatures and radiative forcing series share similar time-series properties and a common nonlinear secular movement. This long-term co-movement is characterized by the existence of time-ordered breaks in the slope of their trend functions. The evidence presented in this paper suggests that while natural forcing factors may help explain the warming of the first part of the century, anthropogenic forcing has been its main driver since the 1970's. In terms of Article 2 of the United Nations Framework Convention on Climate Change, significant anthropogenic interference with the climate system has already occurred and the current climate models are capable of accurately simulating the response of the climate system, even if it consists in a rapid or abrupt change, to changes in external forcing factors. This paper presents a new methodological approach for conducting time-series based attribution studies. PMID:23555866

  3. Evaluation of Continental Precipitation in 20th-Century Climate Simulations: The Utility of Multi-Model Statistics

    SciTech Connect

    Phillips, T J; Gleckler, P J

    2005-11-01

    At the request of the Intergovernmental Panel on Climate Change (IPCC), simulations of 20th-century climate have been performed recently with some 20 global coupled ocean-atmosphere models. In view of its central importance for biological and socio-economic systems, model-simulated continental precipitation is evaluated relative to three observational estimates at both global and regional scales. Many models are found to display systematic biases, deviating markedly from the observed spatial variability and amplitude/phase of the seasonal cycle. However, the point-wise ensemble mean of all the models usually shows better statistical agreement with the observations than does any single model. Deficiencies of current models that may be responsible for the simulated precipitation biases as well as possible reasons for the improved estimate afforded by the multi-model ensemble mean are discussed. Implications of these results for water-resource managers also are briefly addressed.

  4. Simulation of the 19th and 20th century climate with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Bichet, A.; Schär, C.; Wild, M.; Folini, D.

    2009-04-01

    Climate simulations with an atmospheric general circulation model driven with natural and anthropogenic forcings have been carried out from 1870 to 2000. The atmospheric GCM ECHAM5 is interactively coupled to the atmospheric aerosol module HAM, while the SSTs are based on data from the Hadley Center dataset. Aerosol emissions are taken from the National Institute for Environmental Studies (NIES), and include SO2 and black carbon from fossil fuel combustion as well as black carbon from biomass burning. Other forcings included in the simulations are changes in greenhouse gases, DMS, solar output and volcanic activities. Global simulations will give a general overview of the climate evolution since the mid-nineteenth century, and will allow the definition of limits to further regional simulations. Sensitivity experiments are carried out, in order to understand better the impact of the the different forcings on the climate since the mid-nineteenth century. Results are discussed with particular emphasis on the hydrological and radiation conditions under different forcings.

  5. Comparison of 20th century and pre-industrial climate over South America in regional model simulations

    NASA Astrophysics Data System (ADS)

    Wagner, S.; Fast, I.; Kaspar, F.

    2012-10-01

    In this study, we assess how the anthropogenically induced increase in greenhouse gas concentrations affects the climate of central and southern South America. We utilise two regional climate simulations for present day (PD) and pre-industrial (PI) times. These simulations are compared to historical reconstructions in order to investigate the driving processes responsible for climatic changes between the different periods. The regional climate model is validated against observations for both re-analysis data and GCM-driven regional simulations for the second half of the 20th century. Model biases are also taken into account for the interpretation of the model results. The added value of the regional simulation over global-scale modelling relates to a better representation of hydrological processes that are particularly evident in the proximity of the Andes Mountains. Climatic differences between the simulated PD minus PI period agree qualitatively well with proxy-based temperature reconstructions, albeit the regional model overestimates the amplitude of the temperature increase. For precipitation the most important changes between the PD and PI simulation relate to a dipole pattern along the Andes Mountains with increased precipitation over the southern parts and reduced precipitation over the central parts. Here only a few regions show robust similarity with studies based on empirical evidence. However, from a dynamical point-of-view, atmospheric circulation changes related to an increase in high-latitude zonal wind speed simulated by the regional climate model are consistent with numerical modelling studies addressing changes in greenhouse gas concentrations. Our results indicate that besides the direct effect of greenhouse gas changes, large-scale changes in atmospheric circulation and sea surface temperatures also exert an influence on temperature and precipitation changes in southern South America. These combined changes in turn affect the relationship between

  6. Enhanced 20th century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

    NASA Astrophysics Data System (ADS)

    Jungclaus, J. H.; Zanchettin, D.; Chamarro, E. M.; Lohmann, K.

    2013-12-01

    Paleoceanographic reconstructions have revealed recent changes in oceanic heat transport into the Arctic that are unprecedented over the past 2000 to 3000 years [Spielhagen et al., 2011; Dylmer et al., 2013]. The 20th century increase in heat transport is related to intensified Atlantic Water advection and manifests itself in terms of changes in foraminiferal assemblages and geochemical tracers. Here we present results from an ensemble of three simulations covering the last millennium (850 - 2005 CE). The experiments were conducted in the framework of PMIP3/CMIP5 using the Max Planck Institute Earth System Model for paleo applications (MPI-ESM-P). The model features the same grids (ECHAM6: T63/L47, MPIOM:1.5°/L40) as the standard CMIP5 model (MPI-ESM-LR [Jungclaus et al., 2013]) but does not include dynamic vegetation. External forcings are applied following the PMIP3 protocol [Schmidt et al., 2011]. Combining forced simulations over pre-industrial times with those over the last 150 years enables us to put changes observed in the modern period in context with a period where only natural forcing agents were active. Additional long unperturbed control simulations serve to discriminate between forced and internally-generated variability. For the northward oceanic heat transports in the northern North Atlantic and in the Nordic Seas all simulations show pronounced multi-centennial variations and an unprecedented increase in the 20th century. The changes in heat transport can be traced back to changes in the gyre circulation in the subpolar North Atlantic with some local amplification. We investigate the reason for the changes in ocean circulation and atmospheric variability modes and discuss the implications for the role of ocean lateral transports for Arctic amplification of global climate change. Dylmer, C.V. et al. [2013], Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000yr., Clim. Past., 9, 1505-1518. Jungclaus, J.H. et al. [2013

  7. Enhanced 20th century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

    NASA Astrophysics Data System (ADS)

    Jungclaus, J. H.; Lohmann, K.; Zanchettin, D.

    2014-07-01

    Oceanic heat transport variations, carried by the northward flowing Atlantic Water, strongly influence Arctic sea-ice distribution, ocean-atmosphere exchanges, and pan-Arctic temperatures. Paleoceanographic reconstructions from marine sediments near Fram Strait have documented a dramatic increase in Atlantic Water temperatures over the 20th century, unprecedented in the last millennium. Here we present results from Earth system model simulations over the last millennium that reproduce and explain reconstructed integrated quantities such as pan-Arctic temperature evolution during the pre-industrial millennium as well as the exceptional Atlantic Water warming in Fram Strait in the 20th century. The associated increase in ocean heat transfer to the Arctic can be traced back to changes in the ocean circulation in the sub-polar North Atlantic. An interplay between a weakening overturning circulation and a strengthening sub-polar gyre as a consequence of 20th century global warming is identified as driving mechanism for the pronounced warming along the Atlantic Water path toward the Arctic. Simulations covering the late Holocene provide a reference frame that allows us to conclude that the changes during the last century are unprecedented in the last 1150 years and that they cannot be explained by internal variability or natural forcing alone.

  8. Climatic changes between 20th century and pre-industrial times over South America in regional model simulations

    NASA Astrophysics Data System (ADS)

    Wagner, S.; Fast, I.; Kaspar, F.

    2011-09-01

    Two simulations with a regional climate model are analyzed for climatic changes between the late 20th century and a pre-industrial period over central and southern South America. The model simulations have been forced with large-scale boundary data from the global simulation performed with a coupled atmosphere-ocean general circulation model. The regional simulations have been carried out on a 0.44° × 0.44° grid (approx. 50 km × 50 km horizontal resolution). The differences in the external forcings are related to a changed greenhouse gas content of the atmosphere, being higher in the present-day simulation. For validation purposes the climate model is analyzed using a five year long simulation between 1993 and 1997 forced with re-analysis data. The climate model reproduces the main climatic features reasonably well, especially when comparing model output co-located with observational station data. However, the comparison between observed and simulated climate is hampered by the sparse meteorological station network in South America. The present-day simulation is compared with the pre-industrial simulation for atmospheric fields of near-surface temperatures, precipitation, sea level pressure and zonal wind. Higher temperatures in the present-day simulation are evident over entire South America, mostly pronounced over the southern region of the Andes Mountains and the Parana basin. During southern winter the higher temperatures prevail over the entire continent, with largest differences over the central Andes Mountains and the Amazonian basin. Precipitation differences show a more heterogeneous pattern, especially over tropical regions. This might be explained by changes in convective processes acting on small scales. During southern summer wetter conditions are evident over the Amazonian and Parana basin in the present-day simulation. Precipitation increases are evident over Patagonia together with decreases to the north along the western slope of the Andes

  9. An evaluation of 20th century climate for the Southeastern United States as simulated by Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models

    USGS Publications Warehouse

    David E. Rupp

    2016-01-01

    The 20th century climate for the Southeastern United States and surrounding areas as simulated by global climate models used in the Coupled Model Intercomparison Project Phase 5 (CMIP5) was evaluated. A suite of statistics that characterize various aspects of the regional climate was calculated from both model simulations and observation-based datasets. CMIP5 global climate models were ranked by their ability to reproduce the observed climate. Differences in the performance of the models between regions of the United States (the Southeastern and Northwestern United States) warrant a regional-scale assessment of CMIP5 models.

  10. A Time-Series Analysis of the 20th Century Climate Simulations Produced for the IPCC’s Fourth Assessment Report

    PubMed Central

    Estrada, Francisco; Perron, Pierre; Gay-García, Carlos; Martínez-López, Benjamín

    2013-01-01

    In this paper evidence of anthropogenic influence over the warming of the 20th century is presented and the debate regarding the time-series properties of global temperatures is addressed in depth. The 20th century global temperature simulations produced for the Intergovernmental Panel on Climate Change’s Fourth Assessment Report and a set of the radiative forcing series used to drive them are analyzed using modern econometric techniques. Results show that both temperatures and radiative forcing series share similar time-series properties and a common nonlinear secular movement. This long-term co-movement is characterized by the existence of time-ordered breaks in the slope of their trend functions. The evidence presented in this paper suggests that while natural forcing factors may help explain the warming of the first part of the century, anthropogenic forcing has been its main driver since the 1970’s. In terms of Article 2 of the United Nations Framework Convention on Climate Change, significant anthropogenic interference with the climate system has already occurred and the current climate models are capable of accurately simulating the response of the climate system, even if it consists in a rapid or abrupt change, to changes in external forcing factors. This paper presents a new methodological approach for conducting time-series based attribution studies. PMID:23555866

  11. Intercomparison of CMIP5 and CMIP3 simulations of the 20th century maximum and minimum temperatures over India and detection of climatic trends

    NASA Astrophysics Data System (ADS)

    Sonali, P.; Kumar, D. Nagesh; Nanjundiah, Ravi S.

    2016-01-01

    Climate change impact assessment has become one of the most important subjects of the research community because of the recent increase in frequency of extreme events and changes in the spatiotemporal patterns of climate. This paper analyses the ability of 46 coupled climate models from Coupled Model Intercomparison Project phases 3 and 5 (CMIP5 and CMIP3). The performance of each climate model was assessed based on its skills in simulating the current seasonal cycles (monthly) of both maximum temperature and minimum temperature (Tmax, Tmin) over India. The performance measures such as coefficient of correlation (Skill_r), root mean square error (Skill_rmse), and the skill in simulating the observed probability density function (Skill_s) are mainly employed for evaluation of the simulated monthly seasonal cycle. A new metric called Skill_All which is an intersection of the above three metrics has been defined for the first time. A notable enhancement of Skill_All for CMIP5 vis-a-vis CMIP3 is observed. Further, three best CMIP5 models each for Tmax and Tmin were selected. The methodology employed in this study for model assessment is implemented for the first time for India, which establishes a robust foundation for the climate impact assessment study. The seasonal trends in Tmax and Tmin were analyzed over all the temperature homogenous regions of India for different time slots during the 20th century. Significant trends in Tmin can be seen during most of the seasons over the entire Indian region during last four decades. This establishes the signature of climate change over most parts of India.

  12. Observed 20th Century Desert Dust Variability: Impact on Climate and Biogeochemistry

    SciTech Connect

    Mahowald, Natalie; Kloster, Silvia; Engelstaedter, S.; Moore, Jefferson Keith; Mukhopadhyay, S.; McConnell, J. R.; Albani, S.; Doney, Scott C.; Bhattacharya, A.; Curran, M. A. J.; Flanner, Mark G.; Hoffman, Forrest M; Lawrence, David M.; Lindsay, Keith; Mayewski, P. A.; Neff, Jason; Rothenberg, D.; Thomas, E.; Thornton, Peter E; Zender, Charlie S.

    2010-01-01

    Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing or decreasing desert dust in the global average. Here we present observational estimates of desert dust based on paleodata proxies showing a doubling of desert dust during the 20th century over much, but not all the globe. Large uncertainties remain in estimates of desert dust variability over 20th century due to limited data. Using these observational estimates of desert dust change in combination with ocean, atmosphere and land models, we calculate the net radiative effect of these observed changes (top of atmosphere) over the 20th century to be -0.14 {+-} 0.11 W/m{sup 2} (1990-1999 vs. 1905-1914). The estimated radiative change due to dust is especially strong between the heavily loaded 1980-1989 and the less heavily loaded 1955-1964 time periods (-0.57 {+-} 0.46 W/m{sup 2}), which model simulations suggest may have reduced the rate of temperature increase between these time periods by 0.11 C. Model simulations also indicate strong regional shifts in precipitation and temperature from desert dust changes, causing 6 ppm (12 PgC) reduction in model carbon uptake by the terrestrial biosphere over the 20th century. Desert dust carries iron, an important micronutrient for ocean biogeochemistry that can modulate ocean carbon storage; here we show that dust deposition trends increase ocean productivity by an estimated 6% over the 20th century, drawing down an additional 4 ppm (8 PgC) of carbon dioxide into the oceans. Thus, perturbations to desert dust over the 20th century inferred from observations are potentially important for climate and biogeochemistry, and our understanding

  13. Numerical simulation of global temperature change during the 20th century with the IAP/LASG GOALS model

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyan; Guo, Yufu; Shi, Guangyu; Yu, Yongqiang

    2004-04-01

    The IAP/LASG GOALS coupled model is used to simulate the climate change during the 20th century using historical greenhouse gases concentrations, the mass mixing ratio of sulfate aerosols simulated by a CTM model, and reconstruction of solar variability spanning the period 1900 to 1997. Four simulations, including a control simulation and three forcing simulations, are conducted. Comparison with the observational record for the period indicates that the three forcing experiments simulate reasonable temporal and spatial distributions of the temperature change. The global warming during the 20th century is caused mainly by increasing greenhouse gas concentration especially since the late 1980s; sulfate aerosols offset a portion of the global warming and the reduction of global temperature is up to about 0.11°C over the century; additionally, the effect of solar variability is not negligible in the simulation of climate change over the 20th century.

  14. Climate and society in 20th century Mexico

    NASA Technical Reports Server (NTRS)

    Liverman, Diana M.

    1991-01-01

    Mexican agriculture has been greatly transformed by the widespread introduction of 'Green Revolution' technologies (irrigation, chemical fertilizers, and improved seeds), through land reform, and by land use policies oriented to export crops and grain production. Drought prone Mexico provides an excellent case to study how technological and social changes alter the impact of drought on food and agricultural system. A goal is to document and understand how relationships between climate and agriculture in Mexico have changed in the last fifty years. The results for several locations will be interpreted in light of the prospects of regional climate change due to global warming. This analysis will be complimented by four case studies of vulnerability to drought which will use local records and interviews to try and show how environmental, technological, and social changes may have altered the impacts of climate on local agricultural systems.

  15. Atmospheric Weather Noise Characteristics in 20th Century Coupled Atmosphere-Ocean Model Simulations

    NASA Astrophysics Data System (ADS)

    Colfescu, Ioana; Schneider, Edwin

    2016-04-01

    The statistical characteristics of the atmospheric internal variability (hereafter weather noise) for surface pressure (PS) in 20th century simulations of a coupled general circulation model are documented. The weather noise is determined from post-industrial (1871-1998) Community Climate System Model 3 simulations by removing the SST and externally forced responses from the total fields.The forced responses are found from atmosphere-only simulations forced by the SST and external forcing of the coupled runs. The spatial patterns of the main modes of weather noise variability of the noise are found for boreal winter and summer from empirical orthogonal function (EOF) analyses performed globally, and for various regions, including the North Atlantic, the North Pacific, and the equatorial Pacific. The temporal characteristics of the modes are illustrated by power spectra and probability density functions (PDF) of the principal components (PC). Our findings show that, for two different realizations of weather noise, the variability is dominated by large scale spatial structures of the weather noise that resemble observed patterns, and that their relative amplitudes in the CGCM and AGCM simulations are very similar. The regional expression of the seasonally dependent AO-like or AAO-like dominant global pattern is also found in the regional analyses, giving similar PCs. The PCs in the CGCM and the corresponding SST forced AGCM simulations are uncorrelated, but the spectra and PDFs of the CGCM and AGCM PCs are similar. The temporal structures of the PCs are white at timescales larger than few months, so that these modes can be thought of as stochastic forcings (in time) for the climate system. The PDFs of the weather noise PCs are not statistically distinguishable from Gaussian distributions with the same standard deviation. The PDFs do not change substantially between the first and second half of the 20th century.

  16. Fire dynamics during the 20th century simulated by the Community Land Model

    SciTech Connect

    Kloster, Silvia; Mahowald, Natalie; Randerson, Jim; Thornton, Peter E; Hoffman, Forrest M; Levis, Sam; Lawrence, Peter J.; Feddema, Johan J.; Oleson, Keith; Lawrence, David M.

    2011-01-01

    Fire is an integral Earth System process that interacts with climate in multiple ways. Here we assessed the parametrization of fires in the Community Land Model (CLM-CN) and improved the ability of the model to reproduce contemporary global patterns of burned areas and fire emissions. In addition to wildfires we extended CLM-CN to account for fires related to deforestation. We compared contemporary fire carbon emissions predicted by the model to satellite-based estimates in terms of magnitude and spatial extent as well as interannual and seasonal variability. Long-term trends during the 20th century were compared with historical estimates. Overall we found the best agreement between simulation and observations for the fire parametrization based on the work by Arora and Boer (2005). We obtained substantial improvement when we explicitly considered human caused ignition and fire suppression as a function of population density. Simulated fire carbon emissions ranged between 2.0 and 2.4 Pg C/year for the period 1997 2004. Regionally the simulations had a low bias over Africa and a high bias over South America when compared to satellite-based products. The net terrestrial carbon source due to land use change for the 1990s was 1.2 Pg C/year with 11% stemming from deforestation fires. During 2000 2004 this flux decreased to 0.85 Pg C/year with a similar relative contribution from deforestation fires. Between 1900 and 1960 we predicted a slight downward trend in global fire emissions caused by reduced fuels as a consequence of wood harvesting and also by increases in fire suppression. The model predicted an upward trend during the last three decades of the 20th century as a result of climate variations and large burning events associated with ENSO-induced drought conditions.

  17. Effects of Irrigation on Global Climate During the 20th Century

    NASA Technical Reports Server (NTRS)

    Puma, M. J.; Cook, B. I.

    2010-01-01

    Various studies have documented the effects of modern ]day irrigation on regional and global climate, but none, to date, have considered the time ]varying impact of steadily increasing irrigation rates on climate during the 20th century. We investigate the impacts of observed irrigation changes over this century with two ensemble simulations using an atmosphere general circulation model. Both ensembles are forced with transient climate forcings and observed sea surface temperatures from 1902 to 2000; one ensemble includes irrigation specified by a time ]varying data set of irrigation water withdrawals. Early in the century, irrigation is primarily localized over southern and eastern Asia, leading to significant cooling in boreal summer (June.August) over these regions. This cooling spreads and intensifies by century fs end, following the rapid expansion of irrigation over North America, Europe, and Asia. Irrigation also leads to boreal winter (December.February) warming over parts of North America and Asia in the latter part of the century, due to enhanced downward longwave fluxes from increased near ]surface humidity. Precipitation increases occur primarily downwind of the major irrigation areas, although precipitation in parts of India decreases due to a weaker summer monsoon. Irrigation begins to significantly reduce temperatures and temperature trends during boreal summer over the Northern Hemisphere midlatitudes and tropics beginning around 1950; significant increases in precipitation occur in these same latitude bands. These trends reveal the varying importance of irrigation ]climate interactions and suggest that future climate studies should account for irrigation, especially in regions with unsustainable irrigation resources.

  18. Changing Temperature and Precipitation Extremes in Europe's Climate of the 20th Century

    NASA Astrophysics Data System (ADS)

    Klein Tank, Albertus Maria Gerardus

    2004-10-01

    This thesis aims at increasing the knowledge on past changes in extremes through the analysis of historical records of observations at meteorological stations. The key question addressed is: How did the extremes of daily surface air temperature and precipitation change in Europe's climate of the 20th century, and what can we learn from this? The contents is structured along the lines of four follow-up questions: Are the available observational datasets adequate to analyse extremes? Which trends are observed for the daily extremes of surface air temperature and precipitation? Can the observed changes in temperature extremes in recent decades be regarded as a fingerprint of anthropogenic climate change? Do the observed changes guide the development of temperature scenarios for our future climate? Europe is one of the regions of the world that lacked a readily available and accessible dataset of high-resolution observational series with sufficient density and quality to study extremes. Such a dataset was developed for temperature and precipitation and used to detect statistically significant and non-trivial changes in extremes. The temperature trends indicate a coarsening of our climate and the precipitation trends indicate an increase of wet extremes. The calculated trends represent changes that can be due to natural internal processes within the climate system and/or external forcing, which can either be natural (solar irradiance, volcanic aerosols, ozone, etc.) or anthropogenic (greenhouse gases, etc.). Comparisons between the trend patterns of temperature extremes in the station records, the patterns associated with natural variability in the observations, and the patterns of future warming and natural variability as simulated by a climate model reveal fingerprints of anthropogenic warming over Europe. The last part of this thesis goes beyond the observations of the climate of the past and speculates on future changes in extremes. It presents a 'what- if scenario

  19. Intercomparison of 20th century tropical climate model hindcasts and coral δ18O data using a forward proxy model

    NASA Astrophysics Data System (ADS)

    Thompson, D. M.; Evans, M. N.; Ault, T. R.; Cole, J. E.; Emile-Geay, J.

    2009-12-01

    Forward modeling of climate proxies enables identification of uncertainties in the interpretation of high resolution proxy archives in a manner that is complementary to classical inverse methods. By coupling proxy models to climate model output driven with realistic external forcings, a framework for assessment of their consistency with proxy observations over long timescales is created. Here we model reef coral oxygen isotopic composition (δ18O) as a function of sea-surface temperature (SST) and sea-surface salinity (SSS), the latter a linear proxy for the isotopic composition of seawater in the tropics. We first validate this model against a comprehensive network of 20th century coral δ18O measurements. When driven with historical SST and SSS data for the last ~50 years, the forward model is able to capture the spatial and temporal pattern of ENSO variability observed in the corals better than a univariate SST-based model, hence establishing the skill of this bivariate model. We then drive the forward model with SST and SSS from 20th-century simulations of state-of-the-art climate models, such as GFDL CM2.0 (run 1 c3m; Delworth et al, 2006, Wittenberg et al, 2006), to assess the ability of climate models to reproduce tropical climate variability. GFDL CM2.0 forward modeled coral δ18O accurately reproduces the spatio-temporal pattern of the observed coral δ18O trend over the 20th century, and furthermore suggests the trend was primarily driven by increased SSTs. However, the magnitude of the modeled trend is smaller than observed in the corals, suggesting that coral physiology has reacted in a non-linear fashion to the observed climatic forcing, or that GFDL CM2.0's tropical response to external climate forcing is too small. Instead, variance in GFDL modeled corals is dominated by strong interannual variability that is much greater than that observed in corals. The temporal evolution of modeled ENSO variance and frequency over the 20th century is also markedly

  20. Downscaling 20th century flooding events in complex terrain (Switzerland) using the WRF regional climate model

    NASA Astrophysics Data System (ADS)

    Heikkilä, Ulla; Gómez Navarro, Juan Jose; Franke, Jörg; Brönnimann, Stefan; Cattin, Réne

    2016-04-01

    Switzerland has experienced a number of severe precipitation events during the last few decades, such as during the 14-16 November of 2002 or during the 21-22 August of 2005. Both events, and subsequent extreme floods, caused fatalities and severe financial losses, and have been well studied both in terms of atmospheric conditions leading to extreme precipitation, and their consequences [e.g. Hohenegger et al., 2008, Stucki et al., 2012]. These examples highlight the need to better characterise the frequency and severity of flooding in the Alpine area. In a larger framework we will ultimately produce a high-resolution data set covering the entire 20th century to be used for detailed hydrological studies including all atmospheric parameters relevant for flooding events. In a first step, we downscale the aforementioned two events of 2002 and 2005 to assess the model performance regarding precipitation extremes. The complexity of the topography in the Alpine area demands high resolution datasets. To achieve a sufficient detail in resolution we employ the Weather Research and Forecasting regional climate model (WRF). A set of 4 nested domains is used with a 2-km resolution horizontal resolution over Switzerland. The NCAR 20th century reanalysis (20CR) with a horizontal resolution of 2.5° serves as boundary condition [Compo et al., 2011]. First results of the downscaling the 2002 and 2005 extreme precipitation events show that, compared to station observations provided by the Swiss Meteorological Office MeteoSwiss, the model strongly underestimates the strength of these events. This is mainly due to the coarse resolution of the 20CR data, which underestimates the moisture fluxes during these events. We tested driving WRF with the higher-resolved NCEP reanalysis and found a significant improvement in the amount of precipitation of the 2005 event. In a next step we will downscale the precipitation and wind fields during a 6-year period 2002-2007 to investigate and

  1. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region

    USGS Publications Warehouse

    Werner, B.A.; Johnson, W. Carter; Guntenspergen, Glenn R.

    2013-01-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946–1975; 1976–2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species.

  2. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region

    PubMed Central

    Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

    2013-01-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946–1975; 1976–2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species. PMID:24223283

  3. Evidence for 20th century climate warming and wetland drying in the North American Prairie Pothole Region.

    PubMed

    Werner, Brett A; Johnson, W Carter; Guntenspergen, Glenn R

    2013-09-01

    The Prairie Pothole Region (PPR) of North America is a globally important resource that provides abundant and valuable ecosystem goods and services in the form of biodiversity, groundwater recharge, water purification, flood attenuation, and water and forage for agriculture. Numerous studies have found these wetlands, which number in the millions, to be highly sensitive to climate variability. Here, we compare wetland conditions between two 30-year periods (1946-1975; 1976-2005) using a hindcast simulation approach to determine if recent climate warming in the region has already resulted in changes in wetland condition. Simulations using the WETLANDSCAPE model show that 20th century climate change may have been sufficient to have a significant impact on wetland cover cycling. Modeled wetlands in the PPR's western Canadian prairies show the most dramatic effects: a recent trend toward shorter hydroperiods and less dynamic vegetation cycles, which already may have reduced the productivity of hundreds of wetland-dependent species. PMID:24223283

  4. Effect of anthropogenic aerosol forcing on climate change in the North Pacific Ocean during the 20th Century

    NASA Astrophysics Data System (ADS)

    Abe, M.; Watanabe, S.; Kawamiya, M.; Nozawa, T.

    2014-12-01

    Reliable future projection by the climate or Earth system model is crucial for the issue on future climate change. For the reliable future projection, uncertainty of the aerosol effect on the climate change should be reduced, because the uncertainty has been large. Therefore, it is essential to understand the effect of anthropogenic aerosol forcing on climate change in the 20th century. In this study, we have assessed the effect by a comparison between the 20th century historical simulations (20C and piAero) with the aerosol forcing fluctuated realistically over time and fixed in the pre-industrial condition by MIROC-ESM. We focus on the climate change in the North Pacific Ocean (NPO) due to anthropogenic aerosol emitted from China in the late 20th century. In the comparison between the two simulations, there has been little difference in the global mean surface temperature (SAT) from 1851 to 1900. Then the difference appears and reaches to about 0.2 deg. C in 1950's. After 1960, the difference in SAT between the two experiments become large. For SST change in the NPO, small positive trend is found after 1900 in the piAero, but not found in the 20C. Thus, the SST difference in the NPO between the two experiments is significant after 1900. While the positive SST trend in the NPO has been large in the piAero after 1960, SST in the Central NPO shows the negative trend in the 20C. These enlarge SST difference between the two experiments. The negative SST trend in the Central NPO in the 20C is likely to be attributable to an increase of aerosol emission from China. The aerosol increase, which is also found in the NPO, makes solar insolation into the surface decrease mainly through the aerosol indirect effect. This effect decreases SST. Also, the effect is seen in the boreal spring and summer. However, the effect is not found in the piAero. The Pacific Decadal Oscillation (PDO), which is the principal natural variability in the NPO, has been investigated. Linear trend of

  5. Numerical Simulation of the Water Cycle Change Over the 20th Century

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Schubert, Siegfried D.

    2003-01-01

    We have used numerical models to test the impact of the change in Sea Surface Temperatures (SSTs) and carbon dioxide (CO2) concentration on the global circulation, particularly focusing on the hydrologic cycle, namely the global cycling of water and continental recycling of water. We have run four numerical simulations using mean annual SST from the early part of the 20th century (1900-1920) and the later part (1980-2000). In addition, we vary the CO2 concentrations for these periods as well. The duration of the simulations is 15 years, and the spatial resolution is 2 degrees. We use passive tracers to study the geographical sources of water. Surface evaporation from predetermined continental and oceanic regions provides the source of water for each passive tracer. In this way, we compute the percent of precipitation of each region over the globe. This can also be used to estimate precipitation recycling. In addition, we are using the passive tracers to independently compute the global cycling of water (compared to the traditional, Q/P calculation).

  6. Assessment of 20th century global-mean thermosteric sea level rise from CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Meyssignac, Benoit; Angelique, Melet

    2016-04-01

    More than 93% of the energy excess associated with anthropogenic climate change. The resulting ocean warming and thermal expansion is a leading contributor to global mean sea level (GMSL) rise. Confidence in projections of GMSL rise therefore depends on the ability of climate models to reproduce global mean thermosteric sea level (GMTSL) rise over the 20th century. In this study, we compare the GMTSL of climate models of the Coupled Models Intercomparison Project Phase 5 (CMIP5) to observations over 1961-2005. Although the model-ensemble mean is within the uncertainty of observations, the model ensemble exhibits a large spread. We aim at explaining the departure of CMIP5 climate models 20th century GMTSL from observations. We show that climate models' GMTSL rise linearly depends on the time integrated radiative forcing F (under continuously increasing radiative forcing). The constant of proportionality (nu) expresses the transient thermosteric sea level response of the climate system. nu depends on the fraction of excess heat stored in the ocean, the expansion efficiency of heat, the climate feedback parameter and the ocean heat uptake efficiency. Most models show noticeably the same fraction of excess heat stored in the ocean and the same expansion efficiency of heat that are consistent with observations. This is unlike the climate feedback parameter and the ocean heat uptake efficiency, which are significantly different across climate models. These differences in climate feedback parameter and ocean heat uptake efficiency along with differences in time-integrated F across models explain most of the departure of CMIP5 climate models 20th century GMTSL from observations.

  7. Modeling Regional Climate Responses to 17th-20th Century Land Use Change over the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Alder, J. R.; Hostetler, S. W.; Reker, R. R.; Loveland, T. R.; Bernhardt, C. E.; Thompson, R.; Sundquist, E. T.; Willard, D. A.

    2015-12-01

    Regional climate change is the combined response to global and regional radiative forcing, circulation and interactions between the atmosphere and Earth surface. A potentially key component of regional climate change derives from natural and human-caused land use and land-use change (LULC) and related atmosphere-surface feedbacks. In the first step of disentangling and quantifying the effect of LULC over the southeastern United States, we conducted a series of simulations with the RegCM4 regional climate model which includes the Biosphere Atmosphere Transfer Scheme (BATS) surface physics package. Land use and vegetation types determine the specified values of a number of biophysical and physical parameters in BATS such as albedo, roughness length, stomatal resistance, and rooting depth. We ran four simulations in which we specified BATS land use types derived from harmonized reconstructions for 1650, 1850, 1920 and Landsat-based observations for 1992 (Steyaert and Knox, 2008). The simulations were run over a model domain comprising a 20 km × 20 km horizontal grid and 23 atmospheric levels for the period 1990-2000. The boundary conditions for the simulations were derived from the NCAR-NCEP Reanalysis and the NOAA Optimum Interpolated Sea Surface Temperature global data sets. Depending on the time periods considered, the simulations indicate regionally coherent patterns of April-September changes in surface radiation, warming and cooling of up to 2 °C or more, substantial changes in soil moisture and atmospheric humidity associated with conversion of native vegetation to agriculture and agriculture back to forest, draining of wetlands and marshes, and urbanization. Extensive draining of wetlands in the lower Mississippi Valley during the 20th century induced a robust feedback with the atmosphere which suppressed convective summertime precipitation. Our joint analysis of LULC classes and the model simulations suggests a need to be able to disaggregate land use to a

  8. Complex climate controls on 20th century oak growth in Central-West Germany.

    PubMed

    Friedrichs, Dagmar A; Büntgen, Ulf; Frank, David C; Esper, Jan; Neuwirth, Burkhard; Löffler, Jörg

    2009-01-01

    We analyze interannual to multi-decadal growth variations of 555 oak trees from Central-West Germany. A network of 13 pedunculate oak (Quercus robur L.) and 33 sessile oak (Quercus petraea (Matt.) Liebl.) site chronologies is compared with gridded temperature, precipitation, cloud-cover, vapor pressure and drought (i.e., Palmer Drought Severity Index, PDSI) fluctuations. A hierarchic cluster analysis identifies three groups for each oak species differentiated by ecologic settings. When high precipitation is primarily a characteristic for one Q. robur and one Q. petraea cluster, the other clusters are more differentiated by prevailing temperature conditions. Correlation analysis with precipitation and vapor pressure reveals statistically significant (P < or = 0.05) correlations for June (r = 0.51) and annual (r = 0.43) means. Growth of both species at dry sites correlates strongly with PDSI (r = 0.39, P < or = 0.05), and weakly with temperature and cloud-cover. In natural stands, Q. robur responds more strongly to water depletion than Q. petraea. Twenty-one-year moving correlations show positive significant growth response to both PDSI and precipitation throughout the 20th century, except for the 1940s - an anomalously warm decade during which all oak sites are characterized by an increased growth and an enhanced association with vapor pressure and temperature. We suggest that the wider oak rings that are exhibited during this period may be indicative of a nonlinear or threshold-induced growth response to drought and vapor pressure, and run counter to the general response of oak to drought and precipitation that normally would result in suppressed growth in a warmer and drier environment. As the wide rings are formed during the severe drought period of the 20th century, a complex model seems to be required to fully explain the widespread oak growth. Our results indicate uncertainty in estimates of future growth trends of Central European oak forests in a warming and

  9. Response of the everglades ridge and slough landscape to climate variability and 20th-century water management

    USGS Publications Warehouse

    Bernhardt, C.E.; Willard, D.A.

    2009-01-01

    The ridge and slough landscape of the Florida Everglades consists of a mosaic of linear sawgrass ridges separated by deeper-water sloughs with tree islands interspersed throughout the landscape. We used pollen assemblages from transects of sediment cores spanning sawgrass ridges, sloughs, and ridge-slough transition zones to determine the timing of ridge and slough formation and to evaluate the response of components of the ridge and slough landscape to climate variability and 20th-century water management. These pollen data indicate that sawgrass ridges and sloughs have been vegetationally distinct from one another since initiation of the Everglades wetland in mid-Holocene time. Although the position and community composition of sloughs have remained relatively stable throughout their history, modern sawgrass ridges formed on sites that originally were occupied by marshes. Ridge formation and maturation were initiated during intervals of drier climate (the Medieval Warm Period and the Little Ice Age) when the mean position of the Intertropical Convergence Zone shifted southward. During these drier intervals, marsh taxa were more common in sloughs, but they quickly receded when precipitation increased. Comparison with regional climate records suggests that slough vegetation is strongly influenced by North Atlantic Oscillation variability, even under 20th-century water management practices. ?? 2009 by the Ecological Society of America.

  10. Climate-change impact on the 20th-century relationship between the Southern Annular Mode and global mean temperature.

    PubMed

    Wang, Guojian; Cai, Wenju

    2013-01-01

    The positive phase of the El Niño-Southern Oscillation (ENSO) increases global mean temperature, and contributes to a negative phase of the Southern Annular Mode (SAM), the dominant mode of climate variability in the Southern Hemisphere. This interannual relationship of a high global mean temperature associated with a negative SAM, however, is opposite to the relationship between their trends under greenhouse warming. We show that over much of the 20th century this relationship undergoes multidecadal fluctuations depending on the intensity of ENSO. During the period 1925-1955, subdued ENSO activities weakened the relationship. However, a similar weakening has occurred since the late 1970s despite the strong ENSO. We demonstrate that this recent weakening is induced by climate change in the Southern Hemisphere. Our result highlights a rare situation in which climate change signals emerge against an opposing property of interannual variability, underscoring the robustness of the recent climate change. PMID:23784087

  11. Multi-season climate synchronized forest fires throughout the 20th century, northern Rockies, U.S.A.

    PubMed

    Morgan, Penelope; Heyerdahl, Emily K; Gibson, Carly E

    2008-03-01

    We inferred climate drivers of 20th-century years with regionally synchronous forest fires in the U.S. northern Rockies. We derived annual fire extent from an existing fire atlas that includes 5038 fire polygons recorded from 12,070,086 ha, or 71% of the forested land in Idaho and Montana west of the Continental Divide. The 11 regional-fire years, those exceeding the 90th percentile in annual fire extent from 1900 to 2003 (>102,314 ha or approximately 1% of the fire atlas recording area), were concentrated early and late in the century (six from 1900 to 1934 and five from 1988 to 2003). During both periods, regional-fire years were ones when warm springs were followed by warm, dry summers and also when the Pacific Decadal Oscillation (PDO) was positive. Spring snowpack was likely reduced during warm springs and when PDO was positive, resulting in longer fire seasons. Regional-fire years did not vary with El Niño-Southern Oscillation (ENSO) or with climate in antecedent years. The long mid-20th century period lacking regional-fire years (1935-1987) had generally cool springs, generally negative PDO, and a lack of extremely dry summers; also, this was a period of active fire suppression. The climate drivers of regionally synchronous fire that we inferred are congruent with those of previous centuries in this region, suggesting a strong influence of spring and summer climate on fire activity throughout the 20th century despite major land-use change and fire suppression efforts. The relatively cool, moist climate during the mid-century gap in regional-fire years likely contributed to the success of fire suppression during that period. In every regional-fire year, fires burned across a range of vegetation types. Given our results and the projections for warmer springs and continued warm, dry summers, forests of the U.S. northern Rockies are likely to experience synchronous, large fires in the future. PMID:18459335

  12. Climate-driven hydrologic transients in lake sediment records: calibration of groundwater conditions using 20th Century drought

    NASA Astrophysics Data System (ADS)

    Donovan, Joseph J.; Smith, Alison J.; Panek, Valerie A.; Engstrom, Daniel R.; Ito, Emi

    2002-02-01

    The effect of 20th-century drought on groundwater and lakes in a climatically sensitive area of the Northern Great Plains (Grant County, western Minnesota) was investigated by analysis of lake sediments and historical air photos, in conjunction with groundwater flow simulations. Drought caused an observed 4.0 to 5.1 m lake-head decline between 1923 and 1938; all but three either dried completely or declined to <1.7 m depth. From the deepest (Elk Lake), a 210Pb-dated sediment core was analyzed for ostracode species distribution and geochemistry of C. Rawsoni shells (δ 18O, δ 13C, Mg/Ca, Sr/Ca). Mg/Ca and δ 13C increased during drought at the same time that salinity-tolerant ostracodes thrived, suggesting increasing salinity. However, δ 18O decreased during drought, anti-correlative with Mg/Ca. A numerical model for transient response of groundwater flow to drought, modeled after that of 1923-38, was constrained by drought-end recessional strand lines observed on air photos of one lake, with strand line elevations inferred from bathymetry. Simulated lake-water-level declines in the first 15 drought years were consistent with strand line elevations. The rate of decline was exponential at drought onset, slowing as water in lakes and wetlands receded to below land surface and lake evaporation declined. A near-steady state was attained between 40 and 50 simulation years after onset of drought, with the water table from 1-5 m below the level of dry lakebeds and only the two deepest lakes still holding water. They were, however, greatly constricted in area and depth. Simulated evaporation fluxes were reduced by over 50% within 15 years, despite increased ET rates, due to lake area constriction and water table declines. Both relate to land surface morphology beneath and around lakes. Model results suggest that lake-bed elevations exert control on the rate and ultimate level to which groundwater is depressed by drought. The deepest lakes in any region will tend to become

  13. Energy feedbacks of northern high-latitude ecosystems to the climate system due to reduced snow cover during 20th century warming

    USGS Publications Warehouse

    Euskirchen, E.S.; McGuire, A.D.; Chapin, F.S.

    2007-01-01

    The warming associated with changes in snow cover in northern high-latitude terrestrial regions represents an important energy feedback to the climate system. Here, we simulate snow cover-climate feedbacks (i.e. changes in snow cover on atmospheric heating) across the Pan-arctic over two distinct warming periods during the 20th century, 1910-1940 and 1970-2000. We offer evidence that increases in snow cover-climate feedbacks during 1970-2000 were nearly three times larger than during 1910-1940 because the recent snow-cover change occurred in spring, when radiation load is highest, rather than in autumn. Based on linear regression analysis, we also detected a greater sensitivity of snow cover-climate feedbacks to temperature trends during the more recent time period. Pan-arctic vegetation types differed substantially in snow cover-climate feedbacks. Those with a high seasonal contrast in albedo, such as tundra, showed much larger changes in atmospheric heating than did those with a low seasonal contrast in albedo, such as forests, even if the changes in snow-cover duration were similar across the vegetation types. These changes in energy exchange warrant careful consideration in studies of climate change, particularly with respect to associated shifts in vegetation between forests, grasslands, and tundra. ?? 2007 Blackwell Publishing Ltd.

  14. Quantifying the Lack of Consistency between Climate Model Projections and Observations of the Evolution of the Earth's Average Surface Temperature since the Mid-20th Century

    NASA Astrophysics Data System (ADS)

    Michaels, P. J.; Knappenberger, P. C.

    2014-12-01

    Recent climate change literature has been dominated by studies which show that the equilibrium climate sensitivity is better constrained than the latest estimates from the Intergovernmental Panel on Climate Change (IPCC) and the U.S. National Climate Assessment (NCA) and that the best estimate of the climate sensitivity is considerably lower than the climate model ensemble average. From the recent literature, the central estimate of the equilibrium climate sensitivity is ~2°C, while the climate model average is ~3.2°C, or an equilibrium climate sensitivity that is some 40% lower than the model average.To the extent that the recent literature produces a more accurate estimate of the equilibrium climate sensitivity than does the climate model average, it means that the projections of future climate change given by both the IPCC and NCA are, by default, some 40% too large (too rapid) and the associated (and described) impacts are gross overestimates.A quantitative test of climate model performance can be made by comparing the range of model projections against observations of the evolution of the global average surface temperature since the mid-20th century. Here, we perform such a comparison on a collection of 108 model runs comprising the ensemble used in the IPCC's Fifth Assessment Report and find that the observed global average temperature evolution for all trend lengths (with one exception) since 1986 is less than 97.5% of the model distribution, meaning that the observed trends are significantly different from the average trend simulated by climate models. For periods approaching 40 years in length, the observed trend lies outside of (below) the range that includes 95% of all climate model simulations.We conclude that at the global scale, this suite of climate models has failed. Treating them as mathematical hypotheses, which they are, means that it is the duty of scientists to, unfortunately, reject their predictions in lieu of those with a lower climate

  15. Changes in the relationships between climate and silver fir (Abies alba Mill.) growth during the 20th century in the Tuscan Apennine Alps (Middle Italy)

    NASA Astrophysics Data System (ADS)

    D'Aprile, F.; Tapper, N.; Baker, P.; Bartolozzi, L.; Bottacci, A.

    2012-04-01

    In the Tuscan Apennine Alps, recent research has shown that similarity in trends of monthly climate variables (i.e., temperature and rainfall) is non-stationary amongst sites during the 20th century even between sites that differ little in elevation and at a relatively short distance from each other (D'Aprile et al., 2010; D'Aprile et al., 2011). Moreover, the level of correlation between series of monthly climate variables varies irregularly from highly positive to negative over time. We hypothesised that those changing climate conditions, even at the local level, could cause different tree-ring growth responses in silver fir amongst sites. The hypothesis was tested by dendroclimatological analysis, which was applied to study stands in silver fir forests close to the meteorological stations where climate analysis has been made. Results show that the influences of both monthly mean temperature and monthly rainfall on silver fir growth vary greatly during the 20th century in the Tuscan Apennine Alps, and the ways that they change differ with month and amongst sites. Within sites, differences in the relationships between climate variables and silver fir tree-ring growth appear small in spite of different elevation of the study stands. These results contribute a changing point in forest planning and management especially in consideration of the need to adapt forest management and interventions to changing climate conditions and mitigate the impacts on silver fir forests. Moreover, they introduce climate variability as a key parameter in sustainable forest management for biodiversity conservation, socially responsible uses, nature conservation, and survival of the only conifer tree species typical of mountain mixed forest ecosystems in the Apennine Alps.

  16. VEMAP Phase 2 bioclimatic database. I. Gridded historical (20th century) climate for modeling ecosystem dynamics across the conterminous USA

    USGS Publications Warehouse

    Kittel, T.G.F.; Rosenbloom, N.A.; Royle, J. Andrew; Daly, Christopher; Gibson, W.P.; Fisher, H.H.; Thornton, P.; Yates, D.N.; Aulenbach, S.; Kaufman, C.; McKeown, R.; Bachelet, D.; Schimel, D.S.; Neilson, R.; Lenihan, J.; Drapek, R.; Ojima, D.S.; Parton, W.J.; Melillo, J.M.; Kicklighter, D.W.; Tian, H.; McGuire, A.D.; Sykes, M.T.; Smith, B.; Cowling, S.; Hickler, T.; Prentice, I.C.; Running, S.; Hibbard, K.A.; Post, W.M.; King, A.W.; Smith, T.; Rizzo, B.; Woodward, F.I.

    2004-01-01

    Analysis and simulation of biospheric responses to historical forcing require surface climate data that capture those aspects of climate that control ecological processes, including key spatial gradients and modes of temporal variability. We developed a multivariate, gridded historical climate dataset for the conterminous USA as a common input database for the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP), a biogeochemical and dynamic vegetation model intercomparison. The dataset covers the period 1895-1993 on a 0.5?? latitude/longitude grid. Climate is represented at both monthly and daily timesteps. Variables are: precipitation, mininimum and maximum temperature, total incident solar radiation, daylight-period irradiance, vapor pressure, and daylight-period relative humidity. The dataset was derived from US Historical Climate Network (HCN), cooperative network, and snowpack telemetry (SNOTEL) monthly precipitation and mean minimum and maximum temperature station data. We employed techniques that rely on geostatistical and physical relationships to create the temporally and spatially complete dataset. We developed a local kriging prediction model to infill discontinuous and limited-length station records based on spatial autocorrelation structure of climate anomalies. A spatial interpolation model (PRISM) that accounts for physiographic controls was used to grid the infilled monthly station data. We implemented a stochastic weather generator (modified WGEN) to disaggregate the gridded monthly series to dailies. Radiation and humidity variables were estimated from the dailies using a physically-based empirical surface climate model (MTCLIM3). Derived datasets include a 100 yr model spin-up climate and a historical Palmer Drought Severity Index (PDSI) dataset. The VEMAP dataset exhibits statistically significant trends in temperature, precipitation, solar radiation, vapor pressure, and PDSI for US National Assessment regions. The historical climate and

  17. How probable was the 20th century global warming?

    NASA Astrophysics Data System (ADS)

    Papalexiou, Simon Michael; Markonis, Yannis

    2016-04-01

    The increase of global mean temperature during the 20th century, according to the Intergovernmental Panel on Climate Change (IPCC), is very plausible due to the anthropogenic greenhouse gas emissions. In addition, climate model projections suggest that the global mean temperature will further rise during the 21st century. While the vast majority of scientists have endorsed IPCC's conclusions, not a few individual scientists, have expressed a disagreement regarding the validity of climate model projections. In this study, the answer to a fundamental question is sought. That is, how probable was the global warming of the 20th century considering only recorded and reconstructed global mean temperatures values, and assuming that the global mean temperature is a stationary stochastic process. In order to answer this question, a stationary stochastic model is set that incorporates (a) the observed autocorrelation structure of the global mean temperature, (b) past observations of global mean temperature and (c) global, regional and site-specific reconstructions of global mean temperature changes during the last two millennia. Based on an intense Monte Carlo simulation, the probability of a global mean temperature trend with equal or greater slope than the observed one in the 20th century is presented.

  18. To what extent does climate explain variations in reported malaria cases in early 20th century Uganda?

    PubMed

    Tompkins, Adrian M; Larsen, Laragh; McCreesh, Nicky; Taylor, David

    2016-01-01

    Malaria case statistics were analysed for the period 1926 to 1960 to identify inter-annual variations in malaria cases for the Uganda Protectorate. The analysis shows the mid-to-late 1930s to be a period of increased reported cases. After World War II, malaria cases trend down to a relative minimum in the early 1950s, before increasing rapidly after 1953 to the end of the decade. Data for the Western Province confirm these national trends, which at the time were attributed to a wide range of causes, including land development and management schemes, population mobility, interventions and misdiagnosis. Climate was occasionally proposed as a contributor to enhanced case numbers, and unusual precipitation patterns were held responsible; temperature was rarely, if ever, considered. In this study, a dynamical malaria model was driven with available precipitation and temperature data from the period for five stations located across a range of environments in Uganda. In line with the historical data, the simulations produced relatively enhanced transmission in the 1930s, although there is considerable variability between locations. In all locations, malaria transmission was low in the late 1940s and early 1950s, steeply increasing after 1954. Results indicate that past climate variability explains some of the variations in numbers of reported malaria cases. The impact of multiannual variability in temperature, while only on the order of 0.5°C, was sufficient to drive some of the trends observed in the statistics and thus the role of climate was likely underestimated in the contemporary reports. As the elimination campaigns of the 1960s followed this partly climate-driven increase in malaria, this emphasises the need to account for climate when planning and evaluating intervention strategies. PMID:27063740

  19. Attributing the Increase in Northern Hemisphere Hot Summers during the Last Half of the 20th Century and the Recent Climate Hiatus

    NASA Astrophysics Data System (ADS)

    Kamae, Y.; Shiogama, H.; Watanabe, M.; Kimoto, M.

    2014-12-01

    Summertime anomalous high temperatures leading to enormous damages to public health and society are increasing continuously since late 20th century. However, the rise of global surface air temperature (SAT) has apparently been slowed in these 15 years. It is not clear why hot summers become more frequent despite the recent global-warming hiatus. Here we present, using ensembles of an atmospheric general circulation model (AGCM), that the continuous increase of hot summers over the Northern Hemisphere (NH) was largely due to direct effect of radiative forcing by the increasing concentration of greenhouse gases (GHGs) and to natural decadal climate variability. The 10-member AGCM ensemble, when forced by 63-year histories of observed sea surface temperature (SST), aerosols, land cover and GHGs, reproduced well the increasing hot summers, but another ensemble without changes in anthropogenic forcings and ocean surface warming still showed a small increase. Decadal SST variations in the Pacific and Atlantic Ocean contributed to the recent increase of hot summers over North America through atmospheric teleconnections. Analyses of the two and an additional ensembles show that local radiative heating over land due to increasing GHGs contributed by 39% to continuous increase over the mid- and high-latitude land areas. The contribution of the direct effect of anthropogenic forcing is independent of the global SST hiatus, suggesting a continuous increase in heat extremes over the land due to this effect even if the climate hiatus persist for the coming decades.ReferenceKamae, Y., H. Shiogama, M. Watanabe, and M. Kimoto (2014), Attributing the increase in Northern Hemisphere hot summers since the late 20th century. Geophys. Res. Lett., doi:10.1002/2014GL061062.

  20. Role of clouds, aerosols, and aerosol-cloud interaction in 20th century simulations with GISS ModelE2

    NASA Astrophysics Data System (ADS)

    Nazarenko, L.; Rind, D. H.; Bauer, S.; Del Genio, A. D.

    2015-12-01

    Simulations of aerosols, clouds and their interaction contribute to the major source of uncertainty in predicting the changing Earth's energy and in estimating future climate. Anthropogenic contribution of aerosols affects the properties of clouds through aerosol indirect effects. Three different versions of NASA GISS global climate model are presented for simulation of the twentieth century climate change. All versions have fully interactive tracers of aerosols and chemistry in both the troposphere and stratosphere. All chemical species are simulated prognostically consistent with atmospheric physics in the model and the emissions of short-lived precursors [Shindell et al., 2006]. One version does not include the aerosol indirect effect on clouds. The other two versions include a parameterization of the interactive first indirect aerosol effect on clouds following Menon et al. [2010]. One of these two models has the Multiconfiguration Aerosol Tracker of Mixing state (MATRIX) that permits detailed treatment of aerosol mixing state, size, and aerosol-cloud activation. The main purpose of this study is evaluation of aerosol-clouds interactions and feedbacks, as well as cloud and aerosol radiative forcings, for the twentieth century climate under different assumptions and parameterizations for aerosol, clouds and their interactions in the climate models. The change of global surface air temperature based on linear trend ranges from +0.8°C to +1.2°C between 1850 and 2012. Water cloud optical thickness increases with increasing temperature in all versions with the largest increase in models with interactive indirect effect of aerosols on clouds, which leads to the total (shortwave and longwave) cloud radiative cooling trend at the top of the atmosphere. Menon, S., D. Koch, G. Beig, S. Sahu, J. Fasullo, and D. Orlikowski (2010), Black carbon aerosols and the third polar ice cap, Atmos. Chem. Phys., 10,4559-4571, doi:10.5194/acp-10-4559-2010. Shindell, D., G. Faluvegi

  1. SPCZ migration and ENSO events during the 20th century as revealed by climate proxies from a Fiji coral

    NASA Astrophysics Data System (ADS)

    Juillet-Leclerc, A.; Thiria, S.; Naveau, P.; Delcroix, T.; Le Bec, N.; Blamart, D.; Corrège, T.

    2006-09-01

    Instrumental sea surface temperature (SST) and sea surface salinity (SSS) records since 1975 have indicated that migrations of the South Pacific Convergence Zone (SPCZ) are strongly related to El Niño-Southern Oscillation (ENSO) events. To reconstruct independent SSS and SST time series for the past century and document this SPCZ and ENSO relationship prior to 1975, we apply a neural network analysis to seven climate proxies derived from a coral skeleton collected in Fiji. These reconstructions suggest that five SPCZ migrations linked to ENSO occurred between 1908 and 1970 while as many migrations occurred during the last three decades, highlighting the recent enhanced frequency of ENSO occurrence.

  2. The climate of Carpathian Region in the 20th century based on the original and modified Holdridge life zone system

    NASA Astrophysics Data System (ADS)

    Szelepcsényi, Zoltán; Breuer, Hajnalka; Sümegi, Pál

    2014-09-01

    The Holdridge life zone system has already been used a number of times for analysing the effects of climate change on vegetation. But a criticism against the method was formulated that it cannot interpret the ecotones (e.g. forest steppe). Thus, in this paper transitional life zones were also determined in the model. Then, both the original and modified life zone systems were applied for the climatic fields of database CRU TS 1.2. Life zone maps were defined in the Carpathian Region (43.5-50.5° N, 15.5-28° E) for each of five 20-year periods between 1901 and 2000. We estimated correctness of the result maps with another vegetation map using Cohen's Kappa statistic. Finally, temporal changes in horizontal and vertical distribution of life zones were investigated. The coverage of boreal region decreased with 59.46% during the last century, while the warm temperate region became almost two and a half larger (257.36%). The mean centres of those life zones, which were not related to mountains, shifted northward during the investigation period. In case of the most abundant life zone types, the average distribution elevation increased. Using the modified model, the potential distribution of forest steppe could be also identified.

  3. Reproduction of 20th century inter- to multi-decadel surface temperature variablilty in radiatively forced coupled climate models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coupled Model Intercomparison Project 3 simulations of surface temperature were evaluated over the period 1902-1999 to assess their ability to reproduce historical temperature variability at 211 global locations. Model performance was evaluated using the running Mann Whitney-Z method, a technique th...

  4. Late 20th century attribution of drying trends in the Sahel from the Regional Climate Model (RegCM3)

    NASA Astrophysics Data System (ADS)

    Jenkins, Gregory S.; Gaye, Amadou T.; Sylla, Bamba

    2005-11-01

    The RegCM3 has been integrated for the period of 1960-2002 using initial and lateral boundary conditions from the NCEP re-analyses at 6-hour intervals. Greenhouse gas concentrations remain fixed and the land-use/soil properties are not altered. The RegCM3 accurately portrays a trend from wetter conditions in the 1960s to very dry conditions in the 1980s. The dry 1980s temperatures in the Sahel are approximately 3°K warmer than the wet 1960s, caused by a reduction in precipitation and clouds leading to an increase in the net absorbed solar radiation at the surface. This anomalous warming maintains the steepest meridional temperature gradient and therefore the African Easterly Jet in lower latitudes. The initiation of dry conditions starts in June and persists through July and August in the model simulations. The initiation of dry conditions appears to be related to a weaker Tropical Easterly Jet which may be linked to warmer Indian Ocean temperatures over the past several decades.

  5. Role of Clouds, Aerosols, and Aerosol-Cloud Interaction in 20th Century Simulations with GISS ModelE2

    NASA Technical Reports Server (NTRS)

    Nazarenko, Larissa; Rind, David; Bauer, Susanne; Del Genio, Anthony

    2015-01-01

    The key uncertainties in the climate sensitivity to the increasing greenhouse gases lie in the behavior and impact of short-lived species, such as tropospheric aerosols and ozone, and secondly, in the response and impact of the ocean circulation.

  6. Role of Clouds, Aerosols, and Aerosol-Cloud Interaction in 20th Century Simulations with GISS ModelE2

    NASA Technical Reports Server (NTRS)

    Nazarenko, Larissa; Rind, David; Bauer, Susanne; Del Genio, Anthony

    2015-01-01

    We use the new version of NASA Goddard Institute for Space Studies (GISS) climate model, modelE2 with 2º by 2.5º horizontal resolution and 40 vertical layers, with the model top at 0.1 hPa [Schmidt et al., 2014]. We use two different treatments of the atmospheric composition and aerosol indirect effect: (1) TCAD(I) version has fully interactive Tracers of Aerosols and Chemistry in both the troposphere and stratosphere. This model predicts total aerosol number and mass concentrations [Shindell et al., 2013]; (2) TCAM is the aerosol microphysics and chemistry model based on the quadrature methods of moments [Bauer et al., 2008]. Both TCADI and TCAM models include the first indirect effect of aerosols on clouds [Menon et al., 2010]; the TCAD model includes only the direct aerosol effect. We consider the results of the TCAD, TCADI and TCAM models coupled to "Russell ocean model" [Russell et al., 1995], E2-R. We examine the climate response for the "historical period" that include the natural and anthropogenic forcings for 1850 to 2012. The effect of clouds, their feedbacks, as well as the aerosol-cloud interactions are assessed for the transient climate change.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  8. Variability of extreme rainfall over La Plata Basin and Amazon Basin in South America in model simulations of the 20th century and projections under global warming

    NASA Astrophysics Data System (ADS)

    Cavalcanti, I. F.

    2011-12-01

    The two largest river basins in South America are Amazon Basin (AMB) in the tropical region and La Plata Basin (LPB) in subtropical and extratropical regions. Extreme droughts have occurred during this decade in Amazonia region which have affected the transportation, fishing activities with impacts in the local population, and also affecting the forest. Droughts or floods over LPB have impacts on agriculture, hydroelectricity power and social life. Therefore, monthly wet and dry extremes in these two regions have a profound effect on the economy and society. Observed rainfall over Amazon Basin (AMB) and La Plata Basin (LPB) is analyzed in monthly timescale using the Standardized Precipitation Index (SPI), from 1979 to 1999. This period is taken to compare GPCP data with HADCM3 simulations (Hadley Centre) of the 20th century and to analyze reanalyses data which have the contribution of satellite information after 1979. HADCM3 projections using SRES A2 scenario is analyzed in two periods: 2000 to 2020 and 2079 to 2099 to study the extremes frequency in a near future and in a longer timescale. Extreme, severe and moderate cases are identified in the northern and southern sectors of LPB and in the western and eastern sectors of AMB. The main objective is to analyze changes in the frequency of cases, considering the global warming and the associated mechanisms. In the observations for the 20th century, the number of extreme rainy cases is higher than the number of dry cases in both sectors of LPB and AMB. The model simulates this variability in the two sectors of LPB and in the west sector of AMB. In the near future 2000 to 2020 the frequency of wet and dry extremes does not change much in LPB and in the western sector of AMB, but the wet cases increase in the eastern AMB. However, in the period of 2079 to 2099 the projections indicate increase of wet cases in LPB and increase of dry cases in AMB. The influence of large scale features related to Sea Surface Temperature

  9. Climate and polar motion during the GRACE observing period: 2002-2015: Implications for decadal scale oscillations during the 20th Century

    NASA Astrophysics Data System (ADS)

    Ivins, Erik; Adhikari, Surendra; Larour, Eric

    2016-04-01

    The motion of the Earth's pole in space has been observed with great accuracy for the last 115 years. The angular variations of the pole position away from its mean are a well explained at annual and 434-day periods. Variations at annual periods are caused by changes in the mass and angular momentum forced by all Earth surface changes that have near seasonality. The 434-day period is explained as a resonance between the cumulative driving forces having periods near the Chandler wobble free eigenmode of the Earth and is well understood theoretically. The Earth also has a longer-term drift that is explained primarily as a response to the ice age changes in the moments of inertial of the Earth. However, there has been a long-standing search for the origins of pole variations that have a period near 10 years. Using GRACE space gravimetry we show that ice mass losses from Greenland and Antarctica, and when combined with changes in continental hydrology, explain almost all the main features of interannual time scale polar wander. The discovery has broad interdisciplinary implications, as we show that decadal scale pole variations are directly linked to global changes continental water. The energy sources for these pole position changes are, therefore, likely to be associated with decadal scale ocean and atmospheric oscillations that also drive 20th Century on-land wet-dry oscillations at decadal-scale across the globe. Variability in pole position, therefore, offers a tool for assessing past stability of our climate, and for the future, now faced with an increased intensity in the water cycle and more vulnerable to ice sheet instability.

  10. Temporal variability of total cloud cover at a Mediterranean megacity in the 20th century: Evidence from visual observations and climate models

    NASA Astrophysics Data System (ADS)

    Founda, Dimitra; Giannakopoulos, Christos; Pierros, Fragiskos

    2013-04-01

    Cloud cover is one of the major factors that determine the radiation budget and the climate system of the Earth. Moreover, the response of clouds has always been an important source of uncertainty in global climate models. Visual surface observations of clouds have been conducted at the National Observatory of Athens (NOA) since the mid 19th century. The historical archive of cloud reports at NOA since 1860 has been digitized and updated, spanning now a period of one and a half century. Mean monthly values of total cloud cover were derived by averaging subdaily observations of cloud cover (3 observations/day). Changes in observational practice (e.g. from 1/10 to 1/8 units) were considered, however, subjective measures of cloud cover from trained observers introduces some kind of uncertainty in the time series. Data before 1884 were considered unreliable, so the analysis was restricted to the series from 1884 to 2012. The time series of total cloud cover at NOA is validated and correlated with historical time series of other (physically related) variables such as the total sunshine duration as well as DTR (Diurnal Temperature Range) which are independently measured. Trend analysis was performed on the mean annual and seasonal series of total cloud cover from 1884-2012. The mean annual values show a marked temporal variability with sub periods of decreasing and increasing tendencies, however, the overall linear trend is positive and statistically significant (p <0.001) amounting to +2% per decade and implying a total increase of almost 25% for the whole analysed period. These results are in agreement qualitatively with the trends reported in other studies worldwide, especially concerning the period before the mid 20th century. On a seasonal basis, spring and summer series present outstanding positive long term trends, while in winter and autumn total cloud cover reveals also positive but less pronounced long term trends Additionally, an evaluation of cloud cover and

  11. Earthflow response to Pacific Decadal Oscillation-driven climate change: 20th Century trends and predictions for the Eel River, California

    NASA Astrophysics Data System (ADS)

    Mackey, B. H.; Roering, J. J.

    2009-12-01

    Predicting landscape response to climate change is one of the contemporary and pressing challenges in Earth surface process research. We present data from a regional study of large, slow moving earthflows in the Eel River catchment, northern California. A 230 km2 LiDAR dataset and a series of orthorectified aerial photos enables documentation of over 80 individual active earthflow features, including 12 large (>1.5 km long) failures with sufficient displacement (>40 m) to generate a time series of earthflow movement spanning 1944-2006. The displacement data, determined by systematically tracking the position of shrubs growing on earthflow surfaces, cluster into 3 distinct temporal patterns. One group exhibits peak velocities from 1944-1954 with little subsequent movement, while a second group of earthflows attain maximum velocities exceeding 4m/a in the 1960’s. The third group shows non-systematic temporal patterns of movement. Examination of northern California climate records dating from the 1920’s reveals little statistically significant change in measures such as annual rainfall. However, we do observe a significant change in the annual distribution of precipitation, river discharge, and mean annual temperature over the mid part of the 20th Century, potentially attributable to the Pacific Decadal Oscillation (PDO). For example, over the period 1940-1970, the lower quartile of daily Eel River discharge (calculated every water year), is nearly double that recorded for the decades before and after. This implies stronger base flows sustained by higher groundwater levels, conditions conducive to increased earthflow activity. The earthflows within each group of similar temporal behavior share key topographic and morphologic attributes; respectively summarized as disconnection from major channels, a long, well supplied transport zone, and tight channel coupling. Strikingly, the velocity patterns of the second group of earthflows mimic the record of baseflow

  12. Historical flood data series of Eastern Spanish Coast (14th-20th centuries). Improving identification of climatic patterns and human factors of flood events from primary documentary sources

    NASA Astrophysics Data System (ADS)

    Alberola, Armando; Barriendos, Mariano; Gil-Guirado, Salvador; Pérez-Morales, Alfredo; Balasch, Carles; Castelltort, Xavier; Mazón, Jordi; Pino, David; Lluís Ruiz-Bellet, Josep; Tuset, Jordi

    2016-04-01

    Historical flood data series of Eastern Spanish Coast (14th-20th centuries). Improving identification of climatic patterns and human factors of flood events from primary documentary sources Armando Alberola, Barriendos, M., Gil-Guirado, S., Pérez Morales, A., Balasch, C., Castelltort, X., Mazón, J., Pino, D., Ruiz-Bellet, J.L., Tuset, J. Historical flood events in eastern spanish coast have been studied by different research groups and projects. Complexity of flood processes, involving atmospheric, surface and human factors, is not easily understandable when long time series are required. Present analysis from PREDIFLOOD Project Consortium defines a new step of flood event databases: Improved access to primary (documentary) and secondary (bibliographical) sources, data collection for all possible locations where floods are detected, and improved system of classification (Barriendos et al., 2014). A first analysis is applied to 8 selected flood series. Long chronologies from PREDIFLOOD Project for Catalonia region (Girona, Barcelona, Tarragona, Lleida, Tortosa). In addition, to cover all sector of spanish mediterranean coast, we introduce Valencia city in Turia River basin. South Eastern sector is cover with Murcia and Caravaca cities, Segura River basin. Extension of area under study required contributions of research teams experienced in work of documentary primary sources (Alberola, 2006; Gil-Guirado, 2013). Flood frequency analysis for long scale periods show natural climatic oscillations into so-called Little Ice Age. There are general patterns, affecting most of basins, but also some local anomalies or singularities. To explain these differences and analogies it is not enough to use purely climatic factors. In this way, we analyze human factors that have been able to influence the variability of floods along last 6 centuries (demography, hydraulic infrastructures, urban development...). This approach improves strongly understanding of mechanisms producing

  13. Great Universalist of the 20TH Century

    NASA Astrophysics Data System (ADS)

    Gershtein, S. S.

    2013-06-01

    One of the most prominent physicists of the 20th century, Lev Davidovich Landau, was at the same time a great universalist who made fundamental contributions in diverse areas of physics: quantum mechanics, solid state physics, theory of magnetism, phase transition theory, nuclear and particle physics, quantum electrodynamics (QED), low-temperature physics, fluid dynamics, atomic collision theory, theory of chemical reactions, and other disciplines.

  14. [Mexico's healthcare in the 20th century].

    PubMed

    Fajardo Ortiz, Guillermo

    2002-01-01

    The purpose of this article is to present Mexico's healthcare in the 20th century. This was a process that was based on illustrated rationalism, positivism and neopositivism. Knowledge and science used to veer away from all aspects of charity and beneficence. Liberal legacy were favourable to government stocks and the state managed to raise a considerable amount of financial and human resources. PMID:12602086

  15. Dynamics of Water Yield From China's Terrestrial Ecosystems in the 20th Century: Impact of Climate Change, Atmospheric Carbon Dioxide, Tropospheric Ozone, and Land- Use

    NASA Astrophysics Data System (ADS)

    Liu, M.; Tian, H.; Zhang, C.; Ren, W.; Liu, J.

    2006-05-01

    The availability of freshwater resources is critical to China's economic development and human's health. Water yield, the runoff from the drainage basin, is one important index of ecosystem service that directly controls the total freshwater availability and rain erosity. The monsoon climate system and the complexity of natural geography in China lead to substantially spatial and temporal variability in water resources. It has been argued that intensively human activity and air pollution have altered the terrestrial water cycle in the last century. However, little is known about the magnitude and historical trend of water yield across China as well as underlying mechanisms. This study used a process-based Dynamic Land Ecosystem Model (DLEM) to address the effects of multiple stressors on water yield nationwide during 1900 to 2000. These multiple stressors include changes in climate, atmospheric CO2 concentration, tropospheric ozone, and land-use (including cropland expansion, cropland abandonment, urbanization, and irrigation). By using optimal fingerprinting statistical techniques and factorial simulation experiments, we determined the relative contribution of these multiple stressors to water yield for the study period. The simulated results were evaluated against river's runoff records and watershed observations. Our simulated results suggest that the land-use change and precipitation appear to be two primary factors controlling water yield in China.

  16. Antimatter and 20th century science

    NASA Astrophysics Data System (ADS)

    Williams, Gary

    2005-03-01

    This article gives an outline of the history of antimatter from the concept first introduced in 1898 up to the present day and is intended to complement the article 'Antihydrogen on Tap’ on page 229. It is hoped that it will provide enough historical background material along with interesting snippets of information for teachers to feel informed about the topic when in the classroom. Antimatter is the perfect example of 20th century science incorporating quantum mechanics and relativity, and showing progression from a theoretical idea to mass production within the space of 100 years. The final section is about using the idea of antihydrogen in the classroom.

  17. Long Term Changes in Thermal Stratification in a Deep Lake: Measurements From the 20th Century and Simulations For the 21st Century

    NASA Astrophysics Data System (ADS)

    Schladow, G.; Sahoo, G. B.; Forrest, A.

    2014-12-01

    Since the late 1960s, temperature profile data have been collected every 10-12 days at Lake Tahoe, USA. Past analyses have shown an overall warming of the lake at all depths, attributable to measured climate warming. The annual average, volume-weighted lake water temperature of the upper 400 m has increased at a rate of 0.011 deg. C/year since 1969 - 2014. There has been a concurrent evolution in the nature of the thermal stratification. While the maximum value of lake stability has not increased in the last 45 years, the length of time the lake remains stratified has been increased by 22 days, mostly occurring as a result of an earlier onset of spring stratification Using statistically downscaled GCM outputs for two different carbon emission scenarios, 1-D numerical simulations of the lake thermal structure over a 100-year period were performed. The results suggest a continuation and intensification of the already observed trends. Depending on the carbon emission scenario assumed, the length of the stratified season will increase by between 65 and 52 days by 2098 over the 1968 value. Most of the future increase will take place at the end of the season with a delay in the onset of winter. The observed impacts of stratification change on past ecosystem and water quality conditions will be presented, and possible future changes will be discussed. Plausible future states could range from climatic eutrophication to climatic oligotrophication.

  18. External control of 20th century temperature by natural and anthropogenic forcings.

    PubMed

    Stott, P A; Tett, S F; Jones, G S; Allen, M R; Mitchell, J F; Jenkins, G J

    2000-12-15

    A comparison of observations with simulations of a coupled ocean-atmosphere general circulation model shows that both natural and anthropogenic factors have contributed significantly to 20th century temperature changes. The model successfully simulates global mean and large-scale land temperature variations, indicating that the climate response on these scales is strongly influenced by external factors. More than 80% of observed multidecadal-scale global mean temperature variations and more than 60% of 10- to 50-year land temperature variations are due to changes in external forcings. Anthropogenic global warming under a standard emissions scenario is predicted to continue at a rate similar to that observed in recent decades. PMID:11118145

  19. How unusual is the 20th century within the Indo-Pacific Warm Pool?

    NASA Astrophysics Data System (ADS)

    Khider, D.; Stott, L. D.; Saikku, R.; Partin, J. W.; Jackson, C. S.; Hammond, D. E.; Newton, A.; Thunell, R.

    2013-12-01

    Over the past 150 years, global temperatures have increased by 0.6°C. It has been suggested that this increase in temperature, especially since 1980, has been unprecedented over the past millennium. In order to put the current warming trend into context, various efforts are underway to reconstruct the longer pre-instrumental history of climate variability. Here, we present a sea surface temperature (SST) record of the Indo-Pacific Warm Pool (IPWP) for the Common Era by combining five high-resolution records of Globigerinoides ruber Mg/Ca from different locations within the Indonesian Seas. The much broader spatial coverage and enhanced temporal resolution of this composite record allows us to assess whether the observed 20th century warming and the rate of 20th century temperature change within IPWP have been unprecedented in the past two millennia. The novelty of this study is in our approach to uncertainty quantification, which entails Monte-Carlo simulations that simultaneously take into account both age model and proxy uncertainties. First, we used a Monte-Carlo process (n=10,000) to generate possible age models for each sedimentary record used in the composite. This Monte-Carlo approach takes into consideration the analytical uncertainty in the 14C and 210Pb measurements used for chronology, the uncertainty in the calibration curve and the reservoir age, and the subjective nature of the interpolation scheme. Second, we take into consideration two sources of error in the SST estimates: the analytical uncertainty for the Mg/Ca results, which was assumed to be normally distributed and independent from sample to sample, and the uncertainty in the calibration equation, which was assumed to be dependent (i.e. each Monte-Carlo record is converted using a solution of the calibration equation). To do so, we use a Bayesian approach to enumerate possible solutions of the calibration equation. Finally, we binned the resulting SSTs into 20-year, 50-year, and 100-year non

  20. Final Scientific Report for "The Interhemispheric Pattern in 20th Century and Future Abrupt Change in Regional Tropical Rainfall"

    SciTech Connect

    Chiang, John C. H.; Wehner, Michael F.

    2012-10-29

    Convergence Zone (ITCZ) over the course of the 20th century prior to the 1980s. This is based on our detection and attribution analysis of 20th century simulations done by international modeling groups as part of the Coupled Model Intercomparison Project phase 3 (CMIP3). We repeated the same analysis with the current CMIP5 multimodel simulations, with essentially similar results. 3.Future projections of the global interhemispheric thermal gradient suggest a pronounced trend that well exceeds the 20th century range of behavior. The major cause of this trend is due to anthropogenic greenhouse gas emissions, acting in such a way as to warm the North more than the South. This result is based on our analysis of the CMIP3 and 5 simulations of future scenarios. The underlying suggestion is that tropical rainfall may concentrate more northwards in the future climate, though further research is required to more firmly establish that result.Taken together, our results shows the important role of the interhemispheric thermal gradient in determining tropical rainfall changes in the 20th century and future. Our analysis specifically highlights high-latitude North Atlantic sea surface temperature, and anthropogenic sulfate aerosols, as important drivers of the interhemispheric gradient over the 20th century; and anthropogenic greenhouse gases in the 21st. The PI has written a review paper in order to promote the awareness of the interhemispheric gradient amongst the climate science community.Our project was instrumental in developing the career of a postdoctoral scholar, as well as contributing to the research training of three Ph.D. candidates.

  1. Planetary Missions of the 20th Century*

    NASA Astrophysics Data System (ADS)

    Moroz, V. I.; Huntress, W. T.; Shevalev, I. L.

    2002-09-01

    Among of the highlights of the 20th century were flights of spacecraft to other bodies of the Solar System. This paper describes briefly the missions attempted, their goals, and fate. Information is presented in five tables on the missions launched, their goals, mission designations, dates, discoveries when successful, and what happened if they failed. More detailed explanations are given in the accompanying text. It is shown how this enterprise developed and evolved step by step from a politically driven competition to intense scientific investigations and international cooperation. Initially, only the USA and USSR sent missions to the Moon and planets. Europe and Japan joined later. The USSR carried out significant research in Solar System exploration until the end of the 1980s. The Russian Federation no longer supports robotic planetary exploration for economic reasons, and it remains to be seen whether the invaluable Russian experience in planetary space flight will be lost. Collaboration between Russian and other national space agencies may be a solution.

  2. Simulated Atlantic Meridional Overturning Circulation in the 20th century with an ocean model forced by reanalysis-based atmospheric data sets

    NASA Astrophysics Data System (ADS)

    He, Yan-Chun; Drange, Helge; Gao, Yongqi; Bentsen, Mats

    2016-04-01

    Global ocean hindcast simulations for the period 1871-2009 have been run with the ocean-sea ice component of the Norwegian Earth System Model (NorESM-O), forced by an adjusted version of the Twentieth Century Reanalysis version 2 data set (20CRv2 data set), as well as by the commonly used second version of atmospheric forcing data set for the Coordinated Ocean-ice Reference Experiments phase-II (CORE-II) for the period 1948-2007 (hereafter CORE.v2 data set). The simulated Atlantic Meridional Overturning Circulation (AMOC) in the 20CR and the CORE simulations have comparable variability as well as mean strength during the last three decades of the integration. The simulated AMOC undergoes, however, distinctly different evolutions during the period 1948-1970, with a sharply declining strength in CORE but a gradual increase in 20CR. Sensitivity experiments suggest that differences in the wind forcing between CORE and 20CR have major impact on the simulated AMOCs during this period. It is furthermore found that differences in the air temperature between the two data sets do contribute to the differences in AMOC, but to a much lesser degree than the wind. An additional factor for the diverging AMOC in the two decades following 1948 is the inevitable switching of atmospheric forcing fields in 1948 in the CORE.v2-based runs due to the cyclic spin-up procedure of the ocean model. The latter is a fundamental issue for any ocean hindcast simulation. The ocean initial state mainly influence the actual value but to a lesser degree also the temporal evolution (variability) of AMOC. It may take about two decades for the AMOC to adjust to a new atmospheric state during the spin-up, although a dynamically balanced ocean initial state tends to reduce the adjustment time and the magnitude of the deviation, implying that an ocean model run with atmospheric forcing fields extending back in time, like 20CRv2, can be used to extend the reliable duration of CORE-type of simulations.

  3. Simulated Atlantic Meridional Overturning Circulation in the 20th century with an ocean model forced by reanalysis-based atmospheric data sets

    NASA Astrophysics Data System (ADS)

    He, Yan-Chun; Drange, Helge; Gao, Yongqi; Bentsen, Mats

    2016-04-01

    Global ocean hindcast simulations for the period 1871--2009 have been run with the ocean-sea ice component of the Norwegian Earth System Model (NorESM-O), forced by an adjusted version of the Twentieth Century Reanalysis version 2 data set (20CRv2 data set), as well as by the commonly used second version of atmospheric forcing data set for the Coordinated Ocean-ice Reference Experiments phase-II (CORE-II) for the period 1948--2007 (hereafter CORE.v2 data set). The simulated Atlantic Meridional Overturning Circulation (AMOC) in the 20CR and the CORE simulations have comparable variability as well as mean strength during the last three decades of the integration. The simulated AMOC undergoes, however, distinctly different evolutions during the period 1948--1970, with a sharply declining strength in CORE but a gradual increase in 20CR. Sensitivity experiments suggest that differences in the wind forcing between CORE and 20CR have major impact on the simulated AMOCs during this period. It is furthermore found that differences in the air temperature between the two data sets do contribute to the differences in AMOC, but to a much lesser degree than the wind. An additional factor for the diverging AMOC in the two decades following 1948 is the inevitable switching of atmospheric forcing fields in 1948 in the CORE.v2-based runs due to the cyclic spin-up procedure of the ocean model. The latter is a fundamental issue for any ocean hindcast simulation. The ocean initial state mainly influence the actual value but to a lesser degree also the temporal evolution (variability) of AMOC. It may take about two decades for the AMOC to adjust to a new atmospheric state during the spin-up, although a dynamically balanced ocean initial state tends to reduce the adjustment time and the magnitude of the deviation, implying that an ocean model run with atmospheric forcing fields extending back in time, like 20CRv2, can be used to extend the reliable duration of CORE-type of simulations.

  4. Milestones in the 20th century.

    PubMed

    Bergmann, Karl-Christian

    2014-01-01

    From its very beginning, the 20th century represented the period of the main breakthrough for allergology as a clinical and scientific entity. The first years of this period were extraordinarily exciting because of the discovery of the anaphylactic reaction in 1902 and its clinical diagnosis as 'local anaphylaxis', 'serum sickness' (1903) or even as 'anaphylactic shock' (1907). The term 'allergy' was coined in 1906 and led to the recognition of allergic diseases as a pathogenetic entity. The first patient organization of hay fever sufferers was founded in Germany in 1900, the same year in which the very first report on immunotherapy was published in New York. In 1911 the era of actual immunotherapy started in London, becoming scientific with the first double-blind study in 1956, and still today being regarded as the backbone of allergology. In 1919 it was shown that allergy could be transferred by blood, in 1921 by serum (Prausnitz-Küstner test) and in 1966 the mystic 'reagins' were recognized as immunoglobulin (Ig) E. The development of the radioallergosorbent test for quantifying specific IgE antibody was a diagnostic landmark for allergists all over the world. The history of allergy diagnosis started with the introduction of a 'functional skin test', named the patch test in 1894. The scratch test was described in 1912 and the patch test in 1931. From 1908 the skin was tested by intracutaneous injections, and from 1930 by a 'puncture test' (a precursor of the prick test) which has been in worldwide use in modified variations since 1959. The rub test ('friction test') was added in 1961. Systematically applied provocation tests started with conjunctival provocation (1907), followed by nasal and bronchial provocation with allergens (1914 and 1925). PMID:24925382

  5. 20th Century Reanalysis Project Ensemble Gateway: 56 Estimates of World Temperature, Pressure, Humidity, and Wind, 1871-2010

    DOE Data Explorer

    This site provides data from the 20th Century Reanalysis Project, offering temperature, pressure, humidity, and wind predictions in 200 km sections all around the earth from 1871 to 2010, every 6 hours, based on historical data. The ensemble mean and standard deviation for each value were calculated over a set of 56 simulations. Data for each of the 56 ensemble members are included here. The dataset consists of files in netCDF 4 format that are available for download from the National Energy Research. The goal of the 20th Century Reanalysis Project is to use a Kalman filter-based technique to produce a global trophospheric circulation dataset at four-times-daily resolution back to 1871. The only dataset available for the early 20th century consists of error-ridden hand-drawn analyses of the mean sea level pressure field over the Northern Hemisphere. Modern data assimilation systems have the potential to improve upon these maps, but prior to 1948, few digitized upper-air sounding observations are available for such a reanalysis. The global tropospheric circulation dataset will provide an important validation check on the climate models used to make 21st century climate projections....[copied from http://portal.nersc.gov/project/20C_Reanalysis/

  6. Global physical water scarcity trajectories for the 20th century

    NASA Astrophysics Data System (ADS)

    Kummu, Matti; de Moel, Hans; Eisner, Stefanie; Flörke, Martina; Siebert, Stefan; Varis, Olli

    2014-05-01

    Food security and the overall wellbeing of human kind are threatened by overexploitation of our freshwater resources. Water scarcity is not only a threat to people, but also to many of the planet's key ecosystems. Due to increasing population pressure, changing water consumption behaviour, and climate change, the threat is projected to become even worse in the future. Water can be physically scarce in two ways: population-driven water shortage occurs in areas where a large population has to depend on a limited resources (indicated by m3/capita/yr), while demand-driven water stress is related to the excessive use of otherwise sufficient water resources (indicated by demand/supply ratio). Although many studies have increased our understanding of current water scarcity and how this may increase in the future, the understanding of trajectories with the past development of the water scarcity is less well understood. To date, studies of past water resources have focused on either water shortage or water stress. We aim to calculate global water scarcity, both water stress and water shortage, for the period 1900-2005. We can thus provide, for the first time, continuous regional trends and local analyses of trajectories of water scarcity for the entire 20th century. By including both dimensions of water scarcity, we can increase the understanding of reasons behind the scarcity. We found that in year 1900 13% of the population (i.e. 0.22 billion people) was living in areas that suffer some kind of water scarcity (<1700 m3/capita/yr or ratio >0.2), while in year 2005 this percentage has increased to 57% (3.80 billion). Especially the population suffering from both high water stress (ratio >0.4) and high water shortage (<1000 m3/capita/yr) has risen considerably, from 2% (29 million people) in 1900, up to 19% (1.2 billion people) in 2005. Geographically these concern mainly northern African regions, the Middle East, Pakistan and parts of India and Northern China. The region of

  7. Flood Hazard Trends in the Mekong River during the 20th century due to monsoon variability

    NASA Astrophysics Data System (ADS)

    Delgado, Jose; Merz, Bruno; Apel, Heiko

    2013-04-01

    Flood trends were investigated in four stations of the lower Mekong River. Two types of changes were accounted for: trend in the mean and trend in the variance of the time series. A trend in the mean implies that the average flood events changed with time. A trend in variance implies that the frequency of low and high magnitude floods changed with time (Merz et al., 2012). Results showed that average flood events decreased during the 20th century. However, due to an increase in variance, the frequency of high magnitude floods increased towards the end of the 20th century (Delgado et al., 2010). This increase could not be detected by usual trend tests like Mann Kendall test or the ordinary least squares regression. The results agree with Katz and Brown (1992), who showed that variance changes are more important that changes in mean, when it comes to flood frequency trends. To investigate possible causes for the detected changes in flood variance, we looked at several large scale atmospheric circulation patterns cited in the literature. The Western Pacific monsoon index (Wang, 2001) showed the greatest resemblance with the flood data. A test of step change in variance was conducted which revealed a coinciding step change in variance between annual maximum discharge and the Western Pacific monsoon. A statistical model where monsoon variance forces flood frequency in the 20th century was tested. The results were statistically significant. This has the advantadge of by-passing the use of precipitation, which in this region is collected in a rather sparse network. Concerning climate change projections, a dynamic index like the Western Pacific monsoon index is better simulated by climate models than tropical precipitation (Wang, 2004, Douville et al. 2005). Another important result is the attribution of the detected changes. The Mekong River basin is located in a transition zone between the Indian and the Pacific oceans. Our results showed that the interannual variability

  8. Testing late 20th century El Nino-Southern Oscillation variability against new coral-based estimates of natural variability

    NASA Astrophysics Data System (ADS)

    Cobb, K. M.; Westphal, N.; Sayani, H. R.; Di Lorenzo, E.; Cheng, H.; Edwards, R.; Charles, C. D.

    2012-12-01

    The El Niño-Southern Oscillation (ENSO) drives large changes in global climate patterns from year to year, yet its sensitivity to continued anthropogenic greenhouse forcing is poorly constrained by both climate models and observational data. Here we analyze over 670 years worth of new, monthly-resolved fossil coral records of ENSO spanning the last 7,000 years. The new records are based on the oxygen isotopic composition (δ18O) of U/Th-dated fossil corals from Christmas (2°N, 157°W) and Fanning (4°N, 160°W) Islands, located in the heart of the ENSO region. The corals document a highly variable ENSO, with reductions in ENSO variance of up to 60% documented in the last millennium and at several points through the reconstruction. Maximum ENSO variance is observed in the early 17th century, when values were up to 15% larger than present. There is no evidence for a precessionally-driven trend in ENSO variance from 6,000 years ago to present that some paleodata and coupled global climate models document. If there is an insolation-related signal in ENSO variance, our data suggest that it is overwhelmed by the large range of natural variability in ENSO. The average ENSO variance for the fossil coral database is 40% lower than late 20th century ENSO variance estimates derived from the fossil corals' modern counterparts. In order to test whether late 20th century ENSO variance is significantly larger than the long-term average implied by the fossil coral data, we employ a Monte Carlo-based approach that uses output from a 2,000-yr-long unforced simulation of the GFDL CM2.1 coupled GCM (Wittenberg, 2009). We first confirm that the model-based distribution of ENSO variance is consistent with the fossil coral-based distribution, which suggests that at least some of the current class of coupled climate models are capable of simulating the intrinsic variability in ENSO reasonably well. We then generate 10,000 pairs of modern and fossil 'pseudocoral' databases, drawing

  9. 20th Century Northern hemisphere jet stream variability

    NASA Astrophysics Data System (ADS)

    Belmecheri, S.; Babst, F.; Trouet, V.; Betancourt, J. L.

    2015-12-01

    The latitudinal position of the Northern hemisphere Jet stream (NHJ) modulates both long term climate trends and the occurrence and frequency of extreme weather events. Precipitation anomalies in particular are associated with NHJ variability and the resulting floods/droughts can have considerable societal and economic impacts. Therefore a better understanding of NHJs role in regional climate is essential in assessing the natural and socio-economic impacts of projected future change in NHJ features. We developed a new climatology of the 300 hPa NHJ based on its seasonally explicit latitudinal position. We used the 20th Century Reanalysis V2 (20CR) data at monthly resolution from 1930-2012 to define the latitudinal position of NHJ as the latitude with the greatest 300 hPa scalar wind speed (m s-1). From these data, we identified four seasons with coherent NHJ patterns (January-February, April-May, July-August, and October-November) and detected longitudinal sectors (total of 15 sectors for all the seasons) where the seasonal jet shows strong spatial coherence. We examined the influence of seasonal NHJ position on the geographical distribution of precipitation and temperature patterns for all sectors. Furthermore, we compared NHJ positions to atmospheric circulation indices at inter-annual and multi-decadal time scales. We found a significant relationship between the NHJ position and the North Atlantic and Arctic oscillations for all seasons and across the majority of longitudinal sectors. In addition to this, our NHJ data set supports a connection with ocean-atmosphere interactions over the northern Pacific Ocean on various time scales: we found significant correlations between the North Pacific Jet and the Pacific Decadal Oscillation for all seasons and with El Niño Southern Oscillation for the winter season. Our results emphasize the importance of the seasonal and spatial characteristics of NHJ, as well as climate teleconnections, when considering regional

  10. Personal reminiscences of ophthalmology giants of the 20th century.

    PubMed

    Tasman, William

    2013-01-01

    This paper records personal reminiscences of seven 20th century ophthalmologists who each in his own way metaphorically split the atom and, thereby, changed ophthalmology forever. In addition to their major contributions, they each shared some very desirable traits. They were gentlemen who were devoted to their families and their families to them. PMID:23768923

  11. The Presidential Timeline of the 20th Century

    ERIC Educational Resources Information Center

    Resta, Paul; Flowers, Betty S.; Tothero, Ken

    2007-01-01

    This article describes the "The Presidential Timeline of the 20th Century," a newly unveiled website jointly created by the Learning Technology Center of The University of Texas at Austin and The National Archives' 12 presidential libraries. This web-based resource provides access to the continually growing store of digitized assets from the…

  12. Educational Expansion and Social Mobility in the 20th Century

    ERIC Educational Resources Information Center

    Breen, Richard

    2010-01-01

    Sociologists consider inequality in educational attainment to be a major cause of inequality between people in their chances of occupying a more advantageous class position. However, there is dispute as to whether educational inequality according to social class background declined during the 20th century. What is not in doubt is the expansion of…

  13. A Revised Estimate of 20th Century Global Mean Sea Level

    NASA Astrophysics Data System (ADS)

    Hay, C.; Morrow, E.; Kopp, R. E., III; Mitrovica, J. X.

    2014-12-01

    One of the primary goals of paleo-sea level research is to assess the stability of ice sheets and glaciers in warming climates. In this context, the 20th century may be thought of as the most recent, recorded, and studied of all past episodes of warming. Over the past decade, a consensus has emerged in the literature that 20th century global mean sea level (GMSL), inferred from tide gauge records, rose at a mean rate of 1.6-1.9 mm/yr. This sea-level rise can be attributed to multiple sources, including thermal expansion of the oceans, ice sheet and glacier mass flux, and anthropogenic changes in land water storage. The Fifth Assessment Report of the IPCC summarized the estimated contributions of these sources over 1901-1990 and computed a total rate, using a bottom-up approach, of ~1.0 mm/yr, which falls significantly short of the rate inferred from tide gauge records. Using two independent probabilistic approaches that utilize models of glacial isostatic adjustment, ocean dynamics, and the sea-level fingerprints of rapid land-ice melt to analyze tide gauge records (Kalman smoothing and Gaussian process regression), we are able to close the 20th century sea-level budget and resolve the above enigma. Our revised estimate for the rate of GMSL rise during 1901-1990 is 1.1-1.3 mm/yr (90% credible interval). This value, which is ~20-30% less than previous estimates, suggests that the change in the GMSL rate from the 20th century to the last two decades (2.7 ± 0.4 mm/yr, consistent with past estimates) was greater than previous estimates. Moreover, since some forward projections of GMSL change into the next century are based in part on past estimates of GMSL change, our revised rate may impact projections of GMSL rise for the 21st century and beyond.

  14. 20th century precipitation changes in the Sahel region: sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Baumgartner, D.; Wild, M.

    2012-04-01

    The 20th century has seen an enormous growth in population and industrialization. These changes are accompanied, among others, by a substantial increase in aerosol emission. To learn more about associated consequences for the climate system we have carried out a comparatively large set of transient sensitivity studies with the global atmosphere only climate model ECHAM5-HAM, using aerosol emission data from NIES (National Institute of Environmental Studies, Japan) and prescribed, observation based sea surface temperatures (SSTs) from the Hadley Center. The sensitivity studies cover the period from 1870 to 2005 and comprise ensembles of simulations (up to 13 members per ensemble), which allow to address the role of different aerosol species, greenhouse gases, and prescribed sea surface temperatures. We present a preliminary analysis of these global simulation data for the Sahel region (land within 20W / 35E / 10N / 20N). The annual cycle as well as the overall temporal evolution of precipitation in the Sahel according to CRU (Climate Research Unit, UK) is captured well by the model simulations: two comparatively wet phases in the 1930s and 1950s, a more or less continuous decline thereafter, and a renewed increase in precipitation since the 1980s. This decline / renewed incline since the 1950s is, however, about twice as strong in the CRU data than in the model data. The sensitivity studies reveal SSTs as a prominent factor for the time evolution of precipitation, while the atmosphere only effect of aerosols plays a minor role for the modeled precipitation. The observation based prescribed SSTs may, however, encapsulate and aerosol effect already.

  15. Early 20th century acoustics apparatus in Iowa

    NASA Astrophysics Data System (ADS)

    Hanson, Roger J.

    2001-05-01

    In the first half of the 20th century G. W. Stewart was a physics faculty member at the University of Iowa (UI) with a distinguished record of research and teaching, especially in acoustics. Much of his research focused on the design and use of several types of acoustical filters. Some apparatus which he developed or utilized are still housed in the Department of Physics and Astronomy or are available in detailed diagrams. Demonstration apparatus (apparently homemade) from his era are still available for use. Carl E. Seashore, a renowned psychologist also at UI in the early 20th century, had interdisciplinary interests linking psychology, speech and hearing, music, and acoustics. He was responsible for obtaining an Henrici harmonic analyzer, a mechanical Fourier analyzer manufactured in Switzerland, a special grant from the state legislature during Depression conditions provided the funding. It resides in the Department of Speech Pathology and Audiology at UI. The Grinnell College Physics Historical Museum houses a set of 18 Helmholtz resonators and a Savart bell and resonator. Apparatus at Iowa State University, the University of Northern Iowa, and other Iowa institutions will also be described. Pictures and diagrams as well as some actual apparatus will be exhibited.

  16. [The 20th century: 100 years of misfortune and splendor].

    PubMed

    Urdaneta-Carruyo, Eliéxer

    2005-01-01

    The 20th century has been one of the most intense and convulsive periods in the History of humanity. A century of paradoxes and contrasts, it began with optimism, it witnessed the apocalypse of two world wars, and finished with unimaginable scientific progress that gave us a new civilization that we cannot yet grasp. In this century, significant events happened that shaped our time and projected their results toward an immediate future. Some of these were providential in understanding man's life, fighting against illnesses and prolonging life, and others were of undeniable social importance for humanity. Some knowledge was based on the work of others. Philosophy was embedded in mathematics, as was science in philosophy, while politics and the economy exercised so decisive an influence in our way of feeling and living that culture and society were affected to the core. Within that century the biggest technological revolution of all the time was also created, as transcendent as it was unimaginable, which put mankind on the road to the stars with the moon landing and in the process created the information society whose signature symbol, the internet, emerged as a new demiurge. However, the 20th century, with all its misfortune and splendor, paradoxes and contrasts, creation and destruction, was the most transcendent in the whole of history and it bequeaths to the future a promising horizon in the search for a renovated meaning of life and a yearning for peaceful coexistence for the whole humanity. PMID:15754756

  17. Meteorological Effects of Land Cover Changes in Hungary during the 20th Century

    NASA Astrophysics Data System (ADS)

    Drüszler, Á.; Vig, P.; Csirmaz, K.

    2012-04-01

    Geological, paleontological and geomorphologic studies show that the Earth's climate has always been changing since it came into existence. The climate change itself is self-evident. Therefore the far more serious question is how much does mankind strengthen or weaken these changes beyond the natural fluctuation and changes of climate. The aim of the present study was to restore the historical land cover changes and to simulate the meteorological consequences of these changes. Two different land cover maps for Hungary were created in vector data format using GIS technology. The land cover map for 1900 was reconstructed based on statistical data and two different historical maps: the derived map of the 3rd Military Mapping Survey of the Austro-Hungarian Empire and the Synoptic Forestry Map of the Kingdom of Hungary. The land cover map for 2000 was derived from the CORINE land cover database. Significant land cover changes were found in Hungary during the 20th century according to the examinations of these maps and statistical databases. The MM5 non-hydrostatic dynamic model was used to further evaluate the meteorological effects of these changes. The lower boundary conditions for this mesoscale model were generated for two selected time periods (for 1900 and 2000) based on the reconstructed maps. The dynamic model has been run with the same detailed meteorological conditions of selected days from 2006 and 2007, but with modified lower boundary conditions. The set of the 26 selected initial conditions represents the whole set of the macrosynoptic situations for Hungary. In this way, 2×26 "forecasts" were made with 48 hours of integration. The effects of land cover changes under different weather situations were further weighted by the long-term (1961-1990) mean frequency of the corresponding macrosynoptic types, to assume the climatic effects from these stratified averages. The detailed evaluation of the model results were made for three different meteorological

  18. The Expression of Emotions in 20th Century Books

    PubMed Central

    Acerbi, Alberto; Lampos, Vasileios; Garnett, Philip; Bentley, R. Alexander

    2013-01-01

    We report here trends in the usage of “mood” words, that is, words carrying emotional content, in 20th century English language books, using the data set provided by Google that includes word frequencies in roughly 4% of all books published up to the year 2008. We find evidence for distinct historical periods of positive and negative moods, underlain by a general decrease in the use of emotion-related words through time. Finally, we show that, in books, American English has become decidedly more “emotional” than British English in the last half-century, as a part of a more general increase of the stylistic divergence between the two variants of English language. PMID:23527080

  19. Contagious rhythm: infectious diseases of 20th century musicians.

    PubMed

    Sartin, Jeffrey S

    2010-07-01

    Infectious diseases have led to illness and death for many famous musicians, from the classical period to the rock 'n' roll era. By the 20th century, as public health improved and orchestral composers began living more settled lives, infections among American and European musicians became less prominent. By mid-century, however, seminal jazz musicians famously pursued lifestyles characterized by drug and alcohol abuse. Among the consequences of this risky lifestyle were tuberculosis, syphilis, and chronic viral hepatitis. More contemporary rock musicians have experienced an epidemic of hepatitis C infection and HIV/AIDS related to intravenous drug use and promiscuity. Musical innovation is thus often accompanied by diseases of neglect and overindulgence, particularly infectious illnesses, although risky behavior and associated infectious illnesses tend to decrease as the style matures. PMID:20660936

  20. Contagious Rhythm: Infectious Diseases of 20th Century Musicians

    PubMed Central

    Sartin, Jeffrey S.

    2010-01-01

    Infectious diseases have led to illness and death for many famous musicians, from the classical period to the rock ’n’ roll era. By the 20th century, as public health improved and orchestral composers began living more settled lives, infections among American and European musicians became less prominent. By mid-century, however, seminal jazz musicians famously pursued lifestyles characterized by drug and alcohol abuse. Among the consequences of this risky lifestyle were tuberculosis, syphilis, and chronic viral hepatitis. More contemporary rock musicians have experienced an epidemic of hepatitis C infection and HIV/AIDS related to intravenous drug use and promiscuity. Musical innovation is thus often accompanied by diseases of neglect and overindulgence, particularly infectious illnesses, although risky behavior and associated infectious illnesses tend to decrease as the style matures. PMID:20660936

  1. 20th century atmospheric deposition and acidification trends in lakes of the Sierra Nevada, California, USA.

    PubMed

    Heard, Andrea M; Sickman, James O; Rose, Neil L; Bennett, Danuta M; Lucero, Delores M; Melack, John M; Curtis, Jason H

    2014-09-01

    We investigated multiple lines of evidence to determine if observed and paleo-reconstructed changes in acid neutralizing capacity (ANC) in Sierra Nevada lakes were the result of changes in 20th century atmospheric deposition. Spheroidal carbonaceous particles (SCPs) (indicator of anthropogenic atmospheric deposition) and biogenic silica and δ(13)C (productivity proxies) in lake sediments, nitrogen and sulfur emission inventories, climate variables, and long-term hydrochemistry records were compared to reconstructed ANC trends in Moat Lake. The initial decline in ANC at Moat Lake occurred between 1920 and 1930, when hydrogen ion deposition was approximately 74 eq ha(-1) yr(-1), and ANC recovered between 1970 and 2005. Reconstructed ANC in Moat Lake was negatively correlated with SCPs and sulfur dioxide emissions (p = 0.031 and p = 0.009). Reconstructed ANC patterns were not correlated with climate, productivity, or nitrogen oxide emissions. Late 20th century recovery of ANC at Moat Lake is supported by increasing ANC and decreasing sulfate in Emerald Lake between 1983 and 2011 (p < 0.0001). We conclude that ANC depletion at Moat and Emerald lakes was principally caused by acid deposition, and recovery in ANC after 1970 can be attributed to the United States Clean Air Act. PMID:25078969

  2. Everglades Plant Community Response to 20th Century Hydrologic Changes

    NASA Astrophysics Data System (ADS)

    Willard, D. A.; Bernhardt, C. E.; Holmes, C. W.; Weimer, L. M.

    2002-05-01

    Pollen records in sediment cores from sites in the historic Everglades allowed us to document the natural variability of the ecosystem over the past 2,000 years and contrast it to 20th century changes in wetland plant communities. The natural system included extensive water-lily sloughs, sawgrass ridges, and scattered tree islands extending from Lake Okeechobee southward through Shark River Slough. Between ~1000 AD and 1200 AD, weedy species such as Amaranthus (water hemp) became more abundant, indicating decreased annual rainfall, shorter hydroperiods, and shallower water depths during this time. After ~1200 AD, vegetation returned to its pre-1000 AD composition. During the 20th century, two phases of hydrologic alteration occurred. Completed by 1930, the first phase included construction of the Hoover Dike, canals linking Lake Okeechobee to the Atlantic Ocean, and the Tamiami Trail. Reconstructions of plant communities indicate that these changes shortened hydroperiods and lowered water depths throughout the Everglades. The extent of water-lily slough communities decreased, and tree islands became larger in Shark River Slough. The second phase resulted from construction of canals and levees in the 1950s, creating three Water Conservation Areas. The response of plant communities to these changes varied widely depending on location in the Everglades. In Loxahatchee NWR, weedy and short-hydroperiod plant species became more abundant in marshes, and species composition of tree islands changed. In Water Conservation Area 2A, cattail replaced sawgrass in marshes with high nutrient influx; the ridge and slough structure of the marshes was replaced by more homogeneous sawgrass marshes; sustained high water levels for more than a decade resulted in loss of tree islands that had existed for more than 1,000 years. In Everglades National Park, the extent of slough vegetation decreased further. Near Florida Bay, the rate of mangrove intrusion into fresh-water marshes

  3. Nutrition and food commodities in the 20th century.

    PubMed

    Martini, Sharon A; Phillips, Marshall

    2009-09-23

    Nutrition in the 20th century is examined with respect to changes in the American diet due to changes in the economy and evolution from an agrarian to an industrialized society. The American farm family diet from two regions of the United States during the 1930s is studied on the basis of overall availability of food commodities. A discussion of the diet staples and differences in farm family health is presented and related to nutritional deficiencies. Beginning in the 1920s through the early 1930s dietary deficiencies became a major focus of public health officials in the United States. Identification of the cause of these human nutritional deficiencies prompted significant research by government agencies such as the U.S. Department of Agriculture, Food and Drug Administration, and National Institutes of Health. Medical schools, universities, pharmaceutical corporations, and private institutions directed their resources into basic chemical research and clinical trials to assess the role of vitamins, minerals, proteins, lipids, carbohydrates, and nutrients for improving human health and nutrition. Chemists played an important role in the discovery of vitamins, minerals, and essential nutrients, validating the efficacy through tedious clinical trials. They developed synthetic vitamins affording food manufacturers and pharmaceutical companies the opportunity to capitalize upon fortifying foods for consumers. The American chemist was also responsible for the development of commodities to maximize crop yield through pesticides and fertilizers. PMID:19719130

  4. Health in Barbados in the 20th century.

    PubMed

    Walrond, E R

    2001-09-01

    At the beginning of the 20th century, Barbados was described as the most unhealthy place in the British Empire; at the end of the century, it is considered amongst the healthiest of developing countries. At the start of the century the statistics were harsh; for example, there was an infant mortality rate of 400 per 1000 live births. It is now between 10 and 15 per 1000 live births. In the last two-thirds of the century, there was a series of ongoing revolutions in Education, Public Health and Hospital Services that affected the health status favourably. The revolution in education was enhanced by the provision of University education starting with Medicine at Mona, Jamaica. Training of doctors expanded to Barbados in 1967 and has been an essential ingredient in the medical care revolution of the last third of the century. In 1953, the first Public Health Centre was opened and Barbados can now boast the most modern public health and primary care facilities. However, modern lifestyles are associated with an epidemic of obesity, diabetes mellitus and hypertension. HIV/AIDS has emerged as a major problem. Health in the 21st century will need to look at lifestyles--the effects of the internal combustion engine, the availability of tools of violence, the lure of 'illegal drugs', personal relationships and gender as well as the driving forces behind the associated lifestyles. PMID:11824009

  5. Essential shift: Scientific revolution in the 20th century

    NASA Astrophysics Data System (ADS)

    Ismay, David K.

    1993-05-01

    With the publishing of Sir Isaac Newton's Principia Mathematica in 1687, a scientific paradigm was established that clearly dominated society for two and half centuries. Many historians of science have identified the Copenhagen interpretation of the quantum theory, formulated c.1927, as having completed a scientific revolution that ended the reign of classical Newtonian science. A rival claim to contemporary scientific revolution, however, has been put forward by Ilya Prigogine and the Brussels school of thermodynamics based on Prigogine's work in non-equilibrium thermodynamics. Using the historical consensus model of scientific revolution first articulated by Thomas S. Kuhn in 1962, this analysis examines the extent to which the Copenhagen interpretation of the quantum theory and the work of IIya Prigogine complete the conceptual, scientific paradigm-shift necessary for a scientific revolution. The resulting historical evidence shows that the Copenhagen interpretation did not complete a paradigm-shift; instead, it was a self-revelation by the scientific community which revealed the essence and fundamental limitations of Newtonian science. Evidence further indicates that the valid claim to scientific revolution in the 20th century lies with the contemporary work of Prigogine and the Brussels school. By abandoning the deterministic, mechanical world-view of the Newtonian paradigm and accepting a new reality of process and irreversible time, Prigogine and his associates have established the foundations for a revolutionary new scientific paradigm.

  6. Tornado activity in Greece within the 20th century

    NASA Astrophysics Data System (ADS)

    Nastos, P. T.; Matsangouras, J. T.

    2010-07-01

    Tornado activity is associated with extreme convective weather which can cause extended damage and even in some cases the loss of life. The complex inland terrain of Greece along with the Ionian Sea at the west and the Aegean Sea at the east appear to be a favorable area for fury phenomena such as tornadoes, waterspouts and funnel clouds. In this study, the spatial and temporal variability of tornado activity in Greece for the period 1900-1999 are presented. The spatial distribution of tornadoes, waterspouts and funnel clouds reveals the vulnerability of specific geographical areas, such as the west Greece and the south Aegean Sea. As far as the intra annual variability is concerned, the maximum of tornado activity dominates within the cold period of the year (October-March) while according to the daily distribution, tornadoes happen frequently during the warm hours of the day. It is remarkable to mention that in Greece, within the 20th century, the tornado activity caused the loss of 4 lifes, the injury of 40 people and numerous damages on human constructions and cultivations.

  7. Tornado activity in Greece within the 20th Century

    NASA Astrophysics Data System (ADS)

    Nastos, P. T.; Matsaggouras, J.

    2009-09-01

    Tornado activity is associated with extreme convective weather which can cause extended damages and even more in some cases the loss of life. The complex inland terrain of Greece along with the Ionion Sea at the west and the Aegean Sea at the east appear to be a favorable area for fury phenomena such as tornado, waterspouts and funnel clouds. In this study, the spatial and temporal variability of tornadoes activity in Greece for the period 1910-1999 are presented. The spatial distribution of tornadoes, waterspouts and funnel clouds reveals the vulnerability of specific geographical areas to tornado activity, such as the western Greece and the southern Aegean Sea. As far as the intra annual variability is concerned, the maximum of tornadoes activity dominates within the cold period of the year (October-March) while according to the daily distribution, tornadoes happen frequently during the warm hours of the day. Furthermore, especially for the cases after 1957, the prevailing synoptic conditions during the tornado activity, based on the analysis of the 500 hPa Geopotential Heights from the archives of the European Centre for Medium-Range Weather Forecasts (ECMWF), were examined, in order to identify the weather patterns associated with the tornado genesis and development. It is remarkable to mention that in Greece, within the 20th century, the tornado activity caused the loss of 4 lifes, the injury of 40 people and numerous damages on human constructions and cultivations.

  8. Psychophysiology by the end of the 20th century.

    PubMed

    Bechtereva, N P

    2000-03-01

    The first real breakthrough in the research of brain organization and thinking in the 20th century was made in neurophysiological investigations performed in direct contact with different sites of the brain, which became possible in diagnosis and treatment. The second breakthrough is happening at present. It is based on the opportunities provided by the non-invasive technique. The theory of the unique character of the brain system consisting of rigid and flexible elements maintaining thinking was created as well as concepts on the reliability in the system, of the error detector and intrinsic protective mechanisms of the brain. In the clinic these data enabled us to help patients who had lost various functions due to stroke. In confirmation with the above theory it was revealed that the same task could be solved in the brain by systems consisting of different elements due to environmental changes or even direction of attention. Data on the functional properties or every zone of the cortex and subcortex as well as cerebellum are rapidly increasing in number. The first priority lies in neurophysiologically penetrating into the physiological character and micromosaic of the activation sites of PET. The main aim of future brain research lies in the investigation of the fine physiological rearrangements which underlie thinking, i.e. deciphering its brain code. This is going to be the basis for the third, extremely valid breakthrough in the research on brain organization of thinking. PMID:10677649

  9. Islamic medical ethics in the 20th century.

    PubMed Central

    Rispler-Chaim, V

    1989-01-01

    While the practice of Western medicine is known today to doctors of all ethnic and religious groups, its standards are subject to the availability of resources. The medical ethics guiding each doctor is influenced by his/her religious or cultural background or affiliation, and that is where diversity exists. Much has been written about Jewish and Christian medical ethics. Islamic medical ethics has never been discussed as an independent field of ethics, although several selected topics, especially those concerning sexuality, birth control and abortions, have been more discussed than others. Islamic medical ethics in the 20th century will be characterised on the basis of Egyptian fatawa (legal opinions) issued by famous Muslim scholars and several doctors. Some of the issues discussed by Islamic medical ethics are universal: abortions, organ transplants, artificial insemination, cosmetic surgery, doctor-patient relations, etc. Other issues are typically Islamic, such as impediments to fasting in Ramadan, diseases and physical conditions that cause infringement of the state of purity, medicines containing alcohol, etc. Muslims' attitudes to both types of ethical issues often prove that pragmatism prevails and the aim is to seek a compromise between Islamic heritage and the achievements of modern medicine, as long as basic Islamic dogma is not violated. PMID:2614792

  10. Evaluation for sustainable agriculture water use from River, Reservoirs and Groundwater in the 20th century

    NASA Astrophysics Data System (ADS)

    Yoshikawa, S.; Yamada, H.; Hanasaki, N.; Kanae, S.

    2011-12-01

    High water stress due to economic growth and climate change (ex. global warming) will be falling into 2 billion people to 4 billion people in the future. Agricultural water use accounting for about 70% of global water consumption might continue to increase due to production of foods and biofuels occurred by population growth in the future. In particular, water demand, food and biofuel production have an inextricable link. It is very important to evaluate these relationship for sustainable water use from past to the future. In this study, we focused on the objective to assess the impact of water withdrawal from various sources (stream flow, medium-sized reservoirs and nonrenewable nonlocal blue water) in the 20th century by considering irrigation area and climate change. Irrigation water withdrawal is the most important water use sector accounting for about 90% of total water withdrawal. First, we make the global spatial database of equipped irrigation area change and medium-sized reservoirs capacity. Then, water withdrawal from each sources for 50 years from 1950 to 2000 were simulated in global-scale at a resolution of 1.0 degree x 1.0 degree using an integrated global water resources model (hereafter, the H08 model). The H08 model can simulate both natural or anthropogenic water flow and anthropogenic water withdrawals. For comparison with our results, distribution of agricultural, industrial and domestic water withdrawals from 1950 to 2000 were estimated by distributing the country-based withdrawal data from AQUASTAT with irrigation area, urban population and total population, respectively. Groundwater withdrawal was then estimated by distributing the country-based withdrawal data based on statistical data from WRI, IGRAC and AQUASTAT with the total water withdrawal. As a result, agricultural water withdrawal change from nonrenewable nonlocal blue water during the past 50 years agreed well with the observed groundwater abstraction based on statistical data. In

  11. On the Cause of the Great North Atlantic Hurricane Drought of the Late 20th Century

    NASA Astrophysics Data System (ADS)

    Emanuel, K.

    2015-12-01

    By all sensible metrics, North Atlantic tropical cyclone activity underwent a pronounced decline from the middle of the 20th Century through the 1980s, and then recovered. A rich literature is devoted to the causes is this hurricane drought, with some arguing that it is part of a natural, multi-decadal oscillation of North Atlantic climate, and others pointing to time-varying radiative forcing as the main cause of the drought. In this work I show that the net variability of Atlantic tropical cyclone activity in the second half of the 20th Century has two spectral peaks: One around a single decade and another at a period close to 70 years. I hypothesize that the longer period variability, of which the drought was a part, was principally owing to time-varying radiative forcing, while the quasi-decadal signal is part of a natural oscillation of North Atlantic climate. To test this hypothesis, I present evidence that the two main contributors to time-varying radiative forcing over the period were CO2 variations and aerosol forcing brought about by a combination of sulfate originating in European sulfur emissions and natural mineral dust from the Sahara, and then show that most of the longer-period variations can be statistically explained by a combination of these two forcing agents, at the same time demonstrating that the spatial pattern on this variability is consistent with the radiative forcing hypothesis. On the other hand, the spatial pattern of the quasi-decadal variations is closely aligned with that of the EOFs of natural variability in a large suite of unforced, coupled climate models, suggesting that this quasi-decadal signal is part of a natural oscillation of the North Atlantic climate.

  12. Analysis of Oceans' Influence on Spring Time Rainfall Variability Over Southeastern South America during the 20th Century

    NASA Astrophysics Data System (ADS)

    Martín, Verónica; Barreiro, Marcelo

    2015-04-01

    Southeastern South America (SESA) rainfall presents large variability from interannual to multidecadal times scales and is influenced by the tropical Pacific, Atlantic and Indian oceans. At the same time, these tropical oceans interact with each other inducing sea surface temperature anomalies in remote basins through atmospheric and oceanic teleconnections. In this study we employ a tool from complex networks to analyze the collective influence of the three tropical oceans on austral spring rainfall variability over SESA during the 20th century. To do so we construct a climate network considering as nodes the observed Niño3.4, Tropical North Atlantic (TNA), and Indian Ocean Dipole (IOD) indices, together with an observed or simulated precipitation (PCP) index over SESA. The mean network distance is considered as a measure of synchronization among all these phenomena during the 20th century. The approach allowed to uncover large interannual and interdecadal variability in the interaction among nodes. In particular, there are two main synchronization periods characterized by different interactions among the oceanic and precipitation nodes. Whereas in the '30s El Niño and the TNA were the main tropical oceanic phenomena that influenced SESA precipitation variability, during the '70s they were El Niño and the IOD. Simulations with an Atmospheric General Circulation Model reproduced the overall behavior of the collective influence of the tropical oceans on rainfall over SESA, and allowed to study the circulation anomalies that characterized the synchronization periods. In agreement with previous studies, the influence of El Niño on SESA precipitation variability might be understood through an increase of the northerly transport of moisture in lower levels and advection of cyclonic vorticity in upper levels. On the other hand, the interaction between the IOD and PCP can be interpreted in two possible ways. One possibility is that both nodes (IOD and PCP) are forced

  13. [The history of sleep research in the 20th century].

    PubMed

    Mathis, J

    1995-12-12

    Not until the 19th century theories on sleep were based upon experimental findings in animal and humans. The so-called 'hypnotoxin theory' culminated, when Legendre and Piéron successfully induced sleep in a dog by transmission of cerebrospinal fluid from a dog deprived of sleep. The main discussion concerning the origin of sleep has been the question if sleep is a passive or an active state. Similarities with coma, the positive Babinski sign and pathoanatomical findings in patients who died after encephalitis lethargica were the arguments for the 'deafferentiation hypothesis'. Bremer's classical brainstem-transsections in cats confirmed this idea. Pavlov was the major representative of the idea that sleep was due to a general inhibition of the brain. Hess induced physiological sleep in cats by electrical stimulation of the diencephalon, proving the active nature of sleep. The introduction of the EEG in animals by Caton and in humans by Berger allowed for the first time the measurement of sleep depth without waking the sleeper. After discovery of the REM sleep periods by Aserinsky and Kleitman in 1953 and the demonstration of periodical sleep cycles by Dement and Kleitman, polysomnography with simultaneous whole night recording of EEG, EMG, electrooculogram and other physiological parameters was established as the major diagnostic tool in sleep disorders. One of the most important questions about the function of sleep is still unresolved. NREM sleep is believed to have a restorative function, whereas REM sleep might be involved in learning processes. According to the sleep interpretation of Sigmund Freud, the dream content represents endogenous wishes which cannot be expressed during wakefulness because of an internal 'sensor'. A more recent theory by Hobson explains the dreams by a very unspecific brainstem activity occurring during REM sleep which projects to the frontal brain and activates stored memory. The most important sleep disease of the 20th century is

  14. Training African-American residents in the 20th century.

    PubMed

    Green-McKenzie, Judith

    2004-03-01

    needed not only to serve minority populations but also to serve as mentors and role models for prospective and current students. The first African-American resident to graduate from the Bellevue Residency Program did indeed treat the underserved, as Dr. Vincent founded the Vincent Sanatorium, dedicated to treating African-American patients, and training African-American nurses and doctors. Over the course of the 20th century, Bellevue Hospital has trained increasing numbers of African-American physicians. It is hoped that, like their predecessor, Dr. Vincent, they will provide care to underserved communities and to the community as a whole, as well as serve as role models for generations to come. PMID:15040520

  15. Brief Communication: Global reconstructions of glacier mass change during the 20th century are consistent

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Leclercq, P. W.; Cogley, J. G.; Jarosch, A. H.

    2015-12-01

    Recent estimates of the contribution of glaciers to sea-level rise during the 20th century are strongly divergent. Advances in data availability have allowed revisions of some of these published estimates. Here we show that outside of Antarctica, the global estimates of glacier mass change obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other, and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist in estimates on regional scales.

  16. Brief Communication: Global glacier mass loss reconstructions during the 20th century are consistent

    NASA Astrophysics Data System (ADS)

    Marzeion, B.; Leclercq, P. W.; Cogley, J. G.; Jarosch, A. H.

    2015-07-01

    Estimates of the contribution of glaciers to sea-level rise during the 20th century that were published in recent years are strongly divergent. Advances in data availability have allowed revisions of some of these published estimates. Here we show that outside of Antarctica, the global estimates of glacier mass loss obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other, and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist in estimates on regional scales.

  17. Distinct causes for two principal U.S. droughts of the 20th century

    NASA Astrophysics Data System (ADS)

    Hoerling, Martin; Quan, Xiao-Wei; Eischeid, Jon

    2009-10-01

    Diagnosis of observational and climate model data reveals that the two major U.S. droughts of the 20th Century had distinct causes. Drought severity over the Southern Plains during 1946-1956 is very likely attributable to remote influences of global sea surface temperatures (SSTs). The Southern Plains and adjacent Southwest are regions particularly sensitive to SST variability, and strong La Niña events that occurred during 1946-1956 exposed that region's drought vulnerability. Drought severity over the Northern Plains during 1932-1939 was likely triggered instead by random atmospheric variability. The Northern Plains lies within a region of comparatively low sensitivity to SST variability, and that region's drought exhibited little sensitivity to SST conditions during the Dust Bowl period. Our results indicate that the southern portions of the Great Plains lie within an epicenter of potentially skillful drought predictions for which an ocean observing system is also a vital drought early warning system.

  18. Canada's Fraser River Basin transitioning from a nival to a hybrid system in the late 20th century

    NASA Astrophysics Data System (ADS)

    Kang, D. H.; Gao, H.; Shi, X.; Dery, S. J.

    2014-12-01

    The Fraser River Basin (FRB) is the largest river draining to the Pacific Ocean in British Columbia (BC), Canada, and it provides the world's most abundant salmon populations. With recent climate change, the shifting hydrologic regime of the FRB is evaluated using hydrological modeling results over the period 1949 to 2006. To quantify the contribution of snowmelt to runoff generation, the ratio RSR, defined as the division of the sum of the snowmelt across the watershed by the integrated runoff over the water year, is employed. Modeled results for RSR at Hope, BC — the furthest downstream hydrometric station of the FRB — show a significant decrease (from 0.80 to 0.65) in the latter part of the 20th century. RSR is found to be mainly suppressed by a decrease of the snowmelt across the FRB with a decline with 107 mm by 26 % along the simulation period. There is also a prominent shift in the timing of streamflow, with the spring freshet at Hope, BC advancing 30 days followed by reduced summer flows for over two months. The timing of the peak spring freshet becomes even earlier when moving upstream of the FRB owing to short periods of time after melting from the snow source to the rivers.

  19. 9. Copy of early 20th century rendering of bird's eye ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Copy of early 20th century rendering of bird's eye view of plant looking north. Rendering owned by the Weatherhead Company. - Cleveland-Chandler Motors Corporation, 300 East 131st Street, Cleveland, Cuyahoga County, OH

  20. 3. Copy of early 20th century lithograph, aerial rendering, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Copy of early 20th century lithograph, aerial rendering, looking south. Rendering owned by Baker Materials Handling Corporation, Cleveland, Ohio. - Rauch & Lang Carriage Company, West Twenty-fifth Street & Monroe Avenue, Cleveland, Cuyahoga County, OH

  1. 1. Copy of early 20th century lithograph showing aerial view, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Copy of early 20th century lithograph showing aerial view, looking west. Rendering owned by Baker Materials Handling Corpation, Cleveland Ohio. - Rauch & Lang Carriage Company, West Twenty-fifth Street & Monroe Avenue, Cleveland, Cuyahoga County, OH

  2. 2. Copy of early 20th century photograph showing Euclid Avenue ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Copy of early 20th century photograph showing Euclid Avenue facade, looking norh. Photograph owned by H.D. Koblitz. - F. B. Stearns Company, Euclid & Lakeview Avenues, Cleveland, Cuyahoga County, OH

  3. 1. Copy of early 20th Century lithograph looking north showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Copy of early 20th Century lithograph looking north showing aerial view of company. Rendering owned by the Crawford Auto- aviation Museum, 10825 East Blvd, Cleveland, Ohio. - Winton Motor Carriage Company, Berea Road & Madison Avenue, Cleveland, Cuyahoga County, OH

  4. Writing by 20th-Century Women Reflects Era's Female-Male Conflict, Critics Argue.

    ERIC Educational Resources Information Center

    Paul, Angus

    1986-01-01

    Two women's study of writing by women in the 20th century found unexpectedly bitter and persistent anxiety and female-male conflict and a common theme of confinement and suppression of emotions and thoughts. (MSE)

  5. 10. Copy of early 20th century photograph of building 'A' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Copy of early 20th century photograph of building 'A' and tennis court looking north. Photograph owned by the Weatherhead Company. - Cleveland-Chandler Motors Corporation, 300 East 131st Street, Cleveland, Cuyahoga County, OH

  6. Comparative analysis of spatial and seasonal variability: Austrian precipitation during the 20th century

    NASA Astrophysics Data System (ADS)

    Matulla, Christoph; Penlap, Edouard K.; Haas, Patrick; Formayer, Herbert

    2003-11-01

    The purpose of this investigation is to demonstrate the usability of objective methods to study the variability of precipitation and hence to contribute to a better understanding of spatial and seasonal variability of Austria's precipitation climate during the 20th century.This will be achieved by regionalizing the intra-annual variability of seasonal precipitation distributions during three non-overlapping 33 year samples (1901-33, 1934-66, 1967-99). Monthly precipitation totals were extracted at 31 Austrian stations from a homogenized long-term climate dataset provided by the Austrian weather service. Three statistical techniques, namely cluster analysis (CLA), rotated empirical orthogonal functions (REOFs) and an unsupervised learning procedure of artificial neural networks (ANNs), were utilized to find homogeneous precipitation regions.The results of summer (June, July, August (JJA)) and winter (December, January, February (DJF)) seasons are presented. The resulting homogeneous precipitation regions depend on season, period and method in this order. Hence, differences introduced by using different methods are small compared with those inferred by investigating different episodes and especially with those related to the seasons.During winter, three homogeneous precipitation regions are found, independent from the period considered. These regions can be assigned to different airflows dominating Austria's climate and triggering precipitation events during the cold season. The situation during summer is more complicated. Thus, at least four clusters are necessary to record the circumstances, which are caused by spatially inhomogeneous convective events such as thunderstorms.

  7. Drought assessment and trends analysis from 20th century to 21st century over China

    NASA Astrophysics Data System (ADS)

    Yang, X. L.; Ren, L. L.; Tong, R.; Liu, Y.; Cheng, X. R.; Jiang, S. H.; Yuan, F.

    2015-06-01

    Droughts are becoming the most expensive natural disasters in China and have exerted serious impacts on local economic development and ecological environment. The fifth phase of the Coupled Model Intercomparison Project (CMIP5) provides a unique opportunity to assess scientific understanding of climate variability and change over a range of historical and future period. In this study, fine-resolution multimodel climate projections over China are developed based on 7 CMIP5 climate models under RCP8.5 emissions scenarios by means of Bilinear Interpolation and Bias Correction. The results of downscaled CMIP5 models are evaluated over China by comparing the model outputs with the England Reanalysis CRU3.1 from 1951 to 2000. Accordingly, the results from the output of downscaled models are used to calculate the Standardized Precipitation Index (SPI). Time series of SPI has been used to identify drought from 20th century to 21st century over China. The results show that, most areas of China are projected to become wetter as a consequence of increasing precipitation under RCP8.5 scenarios. Detailed examination shows that the SPI show a slightly increasing trend in the future period for the most parts of China, but drought in Southwest region of China will become the norm in the future RCP8.5 scenarios.

  8. Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay

    USGS Publications Warehouse

    Cronin, T. M.; Dwyer, G.S.; Kamiya, T.; Schwede, S.; Willard, D.A.

    2003-01-01

    We present paleoclimate evidence for rapid (< 100 years) shifts of ??? 2-4??C in Chesapeake Bay (CB) temperature ???2100, 1600, 950, 650, 400 and 150 years before present (years BP) reconstructed from magnesium/calcium (Mg/Ca) paleothermometry. These include large temperature excursions during the Little Ice Age (???1400-1900 AD) and the Medieval Warm Period (???800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between ???450 and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous temperature maxima between 2200 and 250 years BP (average ???70 years) suggests that multi-decadal processes typical of the North Atlantic Oscillation (NAO) are an inherent feature of late Holocene climate. However, late 19th and 20th century temperature extremes in Chesapeake Bay associated with NAO climate variability exceeded those of the prior 2000 years, including the interval 450-1000 AD, by 2-3??C, suggesting anomalous recent behavior of the climate system. ?? 2002 Elsevier Science B.V. All rights reserved.

  9. Reorganization of the flood-prone atmospheric patterns at the onset of the 20th century?

    NASA Astrophysics Data System (ADS)

    Wilhelm, Bruno; Vogel, Hendrik; Anselmetti, Flavio

    2015-04-01

    studied regions. Comparing all the flood reconstructions over the last 250 years aims at tracking these atmospheric pathways and their possible changes over time. Strong similarities in flood frequency are observed from 1750 to 1900 for the western part (Cévennes, Southern French Alps), while no convincing correlation appears between the other records. Around 1900, a drastic change appears with strong similarities between records of the eastern part (Southern Alps, SE French Alps and NW Italian Alps). In particular, the flood frequency largely increased in the Cévennes during the first part of the 20th century, while this period is one of the most 'quiet' in all other records. Hence, these results suggest a reorganization of the flood-prone atmospheric patterns at the onset of the 20th century.

  10. Introduction: contexts and concepts of adaptability and plasticity in 20th-century plant science.

    PubMed

    Baranski, Marci; Peirson, B R Erick

    2015-04-01

    Nowhere is the problem of understanding the complex linkages between organisms and their environments more apparent than in the science of plants. Today, efforts by scientists to predict and manage the biological consequences of shifting global and regional climates depend on understanding how organisms respond morphologically, physiologically, and behaviorally to changes in their environments. Investigating organismal "adaptability" (or "plasticity") is rarely straightforward, prompting controversy and discourse among and between ecologists and agricultural scientists. Concepts like agro-climatic adaptation, phenotypic plasticity, and genotype-environment interaction (GxE) are key to those debates, and their complex histories have imbued them with assumptions and meanings that are consequential but often opaque. This special section explores the diverse ways in which organismal adaptability has been conceptualized and investigated in the second half of the 20th century, and the multifarious political, economic, environmental, and intellectual contexts in which those conceptions have emerged and evolved. The papers in this section bring together perspectives from the histories of agriculture, population ecology, evolutionary theory, and plant physiology, cutting across Asian, North American, and British contexts. As a whole, this section highlights not only the diversity of meanings of "adaptability" and "plasticity," but also the complex linkages between those meanings, the scientific practices and technologies in which they are embedded, and the ends toward which those practices and technologies are employed. PMID:25641218

  11. Surface solar radiation in 20th century Europe: dimming and brightening as seen by ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Wild, M.

    2012-04-01

    The 20th century has seen a tremendous population growth and industrialization on a global scale. One particular 'hot spot' of these developments is Europe. These changes were accompanied, among others, by a substantial increase in aerosol emission. To learn more about associated consequences for the climate system we have carried out a comparatively large set of transient sensitivity studies with the global atmosphere only climate model ECHAM5-HAM, using aerosol emission data from NIES (National Institute of Environmental Studies, Japan) and prescribed, observation based sea surface temperatures (SSTs) from the Hadley Center. The sensitivity studies cover the period from 1870 to 2005 and comprise ensembles of simulations (up to 13 members per ensemble), which allow to address the role of different aerosol species, greenhouse gases, and prescribed sea surface temperatures. Analyzing these simulation data for Europe, we find a clear decrease of surface solar radiation (SSR) from about 1950 to 1980, followed by a renewed increase. This dimming / brightening is well known from observational data. The modeled and observed magnitude of the phenomenon are in good agreement, although dimming in the model ceases too early. One possible explanation for the latter could lie with the prescribed aerosol emissions, in particular too weak SO2 emissions or a too early reduction of black carbon emissions. Modeled SSR changes show substantial regional differences in magnitude and timing, again in line with observations. The model data further suggests a substantial random / natural variability / cloud component with regard to SSR changes under all sky conditions. While some ensemble members show a much more pronounced dimming than the ensemble average, others show hardly any dimming. Interestingly, the brightening signal after 1990 is found to be more robust in this respect. Surface temperatures bear some imprint of the SSR changes, especially in Eastern Europe, but the dominant

  12. 20th century ethane variability from polar firn air and implications for the methane budget

    NASA Astrophysics Data System (ADS)

    Saltzman, E. S.; Verhulst, K. R.; Aydin, K. M.; Battle, M. O.; Montzka, S. A.; Tang, Q.; Prather, M. J.

    2010-12-01

    Methane and ethane are the most abundant hydrocarbons in the atmosphere and they impact both atmospheric chemistry and climate. Both gases are emitted from fossil fuels and biomass burning, while methane alone has large sources from wetlands, agriculture, landfills and wastewater. Here we use measurements in firn air from Greenland and Antarctica to reconstruct the atmospheric variability of ethane during the 20th century. Ethane levels rose from early in the century until the 1980’s when the trend reverses, with a period of decline over the next 20 years. This variability is primarily driven by changes in ethane emissions from fossil fuels that peaked in the 1960’s and 1970’s at 14-16 Tg/y and dropped to 8-10 Tg/y before the end of the century. The reduction in fossil-fuel sources is likely related to changes in light hydrocarbon recovery during petroleum production and use. The ethane-based emission history implies that the decline in the fossil-fuel source of methane may have started prior to the 1980’s and that the magnitude of the decline is larger than previous estimates.

  13. Potential Predictability of the Sea-Surface Temperature Forced Equatorial East Africa Short Rains Interannual Variability in the 20th Century

    NASA Astrophysics Data System (ADS)

    Bahaga, T. K.; Gizaw, G.; Kucharski, F.; Diro, G. T.

    2014-12-01

    In this article, the predictability of the 20th century sea-surface temperature (SST) forced East African short rains variability is analyzed using observational data and ensembles of long atmospheric general circulation model (AGCM) simulations. To our knowledge, such an analysis for the whole 20th century using a series of AGCM ensemble simulations is carried out here for the first time. The physical mechanisms that govern the influence of SST on East African short rains in the model are also investigated. It is found that there is substantial skill in reproducing the East African short rains variability, given that the SSTs are known. Consistent with previous recent studies, it is found that the Indian Ocean and in particular the western pole of the Indian Ocean dipole (IOD) play a dominant role for the prediction skill, whereas SSTs outside the Indian Ocean play a minor role. The physical mechanism for the influence of the western Indian Ocean on East African rainfall in the model is consistent with previous findings and consists of a gill-type response to a warm (cold) anomaly that induces a westerly(easterly) low-level flow anomaly over equatorial Africa and leads to moisture flux convergence (divergence) over East Africa. On the other hand, a positive El Nino-Southern Oscillation (ENSO) anomaly leads to a spatially non-coherent reducing effect over parts of East Africa, but the relationship is not strong enough to provide any predictive skill in our model. The East African short rains prediction skill is also analyzed within a model-derived potential predictability framework and it is shown that the actual prediction skill is broadly consistent with the model potential prediction skill. Low-frequency variations of the prediction skill are mostly related to SSTs outside the Indian Ocean region and are likely due to an increased interference of ENSO with the Indian Ocean influence on East African short rains after the mid-1970s climate shift.

  14. 20th century acidification and warming as recorded in two alpine lakes in the Tatra Mountains (South Poland, Europe).

    PubMed

    Gasiorowski, Michał; Sienkiewicz, Elwira

    2010-02-01

    Sediment profiles of two alpine lakes located in the Tatra Mountains, the Toporowy Staw Nizni (TSN) and the Zielony Staw Gasienicowy (ZSG), were studied for their chronology, lithology, diatom and cladoceran remains. The sediment sequences, 50cm long from TSN and 30cm long from ZSG, were deposited during the last 1000 and 300 years, respectively. Vertical changes in lithology, diatom and Cladocera allow the reconstruction of three periods in the lakes' evolution: mild climatic conditions during Medieval Warm Period (MWP, only in TSN), severe conditions between the end of 14th and 19th centuries, identified as the Little Ice Age (LIA), and 20th century warming. The LIA was recorded in the sediments of both lakes in the form of intensified erosion and lower lake ecosystem productivity, as indicated by organic matter lower content, changes in diatom species composition, and decline in Daphnia. The 20th century was a time of acidification in both lakes. The scale of acidification was assessed based on the decline in diatom-inferred pH (DI-pH). DI-pH dropped by 1.2 pH units during the last century in TSN and by 0.4 pH unit in ZSG. The decline of DI-pH was noted in both lakes, but its intensity was clearly higher in TSN due to the lower acid neutralisation capacity (ANC) of this lake. The lower pH during the final decades of the 20th century was lethal to some water organisms while attracting others, such as Daphnia. The Daphnia population increased after the pH drop, probably due to the high food flexibility of this genus. A similar increase was not observed in ZSG, where planktonivorous fishes were introduced in the 1940s, which effectively limited the crustacean plankton density. PMID:19896170

  15. Centenarian scientists: an unusual cluster newly formed in the 20th century.

    PubMed

    Sri Kantha, S

    2001-12-01

    From biographical data sources on ranking scientists, I was able to identify 35 centenarians. Among these, only one (Michel Chevereul from France) lived before the 20th century. Since the remaining 34 individuals became centenarians only from 1965, I propose that centenarian scientists are an unusual cluster, first formed in the 20th century. Among these, all except one (Alice Hamilton) were men. Six centenarian scientists, including Hamilton, had received professional medical training. The nationality ranks of the 34 centenarian scientists identified in the 20th century show 26 Americans, 6 British, one German and one French. Four of the 26 Americans were immigrants from Europe. At least three centenarians, namely Michael Heidelberger, Nathaniel Kleitman and Victor Hamburger, belong to the 'Nobel class' category, being pioneers in the disciplines of immunochemistry, sleep physiology and neuroembryology respectively. PMID:11918440

  16. A Comparison of Variable Total and Ultraviolet Solar Irradiance Inputs to 20 th Century Global Warming

    NASA Astrophysics Data System (ADS)

    Foukal, P. V.

    2002-05-01

    Analysis of spaceborne radiometry has shown that the total solar irradiance variation over the past two activity cycles was approximately proportional to the weighted difference between areas of dark spots and bright faculae and enhanced network. Empirical models of ultraviolet irradiance variation indicate that its behavior is dominated by changes in area of the bright component alone, whose photometric contrast increases at shorter wavelength.This difference in time behavior of total and UV irradiances could help to discriminate between their relative importance in forcing of global warming. Our recent digitization of archival Ca K images from Mt Wilson and NSO provides the first direct measurement of variations in area of the bright component, extending between 1915 and 1999 (previous models have relied on the sunspot number or other proxies to estimate the bright - component contribution). We use these more direct measurements to derive the time behavior of solar total and UV irradiance variation, over this period .We find that they are significantly different;the total irradiance variation accounts for over 80 percent of the variance in global temperature during this period, while the ultraviolet irradiance variation accounts for only about 20 percent. The amplitude of total irradiance variation in our model is smaller than required to influence global warming,in current climate models.Also, the impact of sulfate aerosol variations on the extended cooling between the 1940's and 1970's must be better understood before the significance of correlations between 20 th century global warming, and any solar activity index can be properly assessed. Despite these caveats, the lower correlation we find between global temperature and UV,compared to total, irradiance requires consideration in the search for physical mechanisms linking solar activity and climate. This work was supported in part under NASA grant NAG5-7607 to CRI, Inc., and NAG5-10998 to the Applied Physics

  17. Potential forest fire danger over Northern Eurasia: Changes during the 20th century

    NASA Astrophysics Data System (ADS)

    Groisman, Pavel Ya.; Sherstyukov, Boris G.; Razuvaev, Vyacheslav N.; Knight, Richard W.; Enloe, Jesse G.; Stroumentova, Nina S.; Whitfield, Paul H.; Førland, Eirik; Hannsen-Bauer, Inger; Tuomenvirta, Heikki; Aleksandersson, Hans; Mescherskaya, Anna V.; Karl, Thomas R.

    2007-04-01

    Significant climatic changes over Northern Eurasia during the 20th century have been reflected in numerous variables of economic, social, and ecological interest, including the natural frequency of forest fires. For the former USSR, we are now using the Global Daily Climatology Network and a new Global Synoptic Data Network archive, GSDN, created jointly by U.S. National Climatic Data Center and Russian Research Institute for Hydrometeorological Information. Data from these archives (approximately 1500 of them having sufficiently long meteorological time series suitable for participation in our analyses) are employed to estimate systematic changes in indices used in the United States and Russia to assess potential forest fire danger. We use four indices: (1) Keetch-Byram Drought Index, (KBDI; this index was developed and widely used in the United States); (2) Nesterov, (3) Modified Nesterov, and (4) Zhdanko Indices (these indices were developed and widely used in Russia). Analyses show that after calibration, time series of the days with increased potential forest fire danger constructed using each of these three indices (a) are well correlated and (b) deliver similar conclusions about systematic changes in the weather conditions conducive to forest fires. Specifically, over the Eastern half of Northern Eurasia (Siberia and the Russian Far East) statistically significant increases in indices that characterize the weather conditions conducive to forest fires were found. These areas coincide with the areas of most significant warming during the past several decades south of the Arctic Circle. West of the Ural Mountains, the same indices show a steady decrease in the frequency of "dry weather summer days" during the past 60 yr. This study is corroborated with available statistics of forest fires and with observed changes in drought statistics in agricultural regions of Northern Eurasia.

  18. Mothers and Daughters in 20th Century Native American and Immigrant Autobiography.

    ERIC Educational Resources Information Center

    Bannan, Helen M.

    The bulk of testimony in the writings and recorded histories of the daughters of immigrants and the first generation of Native Americans educated in American schools in the late 19th and early 20th centuries reveals that, although the ties between female generations became more tangled with the strains of acculturation, the bonds were stretched…

  19. The wings of Daedalus: The convergence of myth and technology in 20th century culture

    NASA Technical Reports Server (NTRS)

    Kowitt, Mark E.; Kaplan, Michael S.

    1993-01-01

    In the second half of the 20th century, age-old human fantasies of leaving the Earth and touching the stars have been fulfilled by advances in space science and technology, whose roots are threaded through our history. Current advances are so explosive that the fundamental orientation of Western culture is being radically altered.

  20. Ottoman Greek Education System and Greek Girls' Schools in Istanbul (19th and 20th Centuries)

    ERIC Educational Resources Information Center

    Daglar Macar, Oya

    2010-01-01

    Modernization efforts in education, which were initiated in the 19th century, can be seen as forerunners of the modernization attempts in the Republic period. In this article, Greek education system in the Ottoman Empire will be discussed and the effects and importance of the changes observed in Greek girls' education in 19th and 20th centuries on…

  1. Cultivating Swedishness? Examples of Imagined Kinship during the First Half of the 20th Century

    ERIC Educational Resources Information Center

    Thomasson, Adrian

    2015-01-01

    Different representations of "Swedishness," as expressions of altered kinds of imagined kinship in the Swedish educational system during the first half of the 20th century, are discussed. It is argued that even though the curriculum changed, from a more religious one focusing on fostering loyalty and moral commitment to "God, the…

  2. From Generation to Generation: Oral Histories of Scientific Innovations from the 20th Century

    ERIC Educational Resources Information Center

    Bedrossian, Mindy J.

    2010-01-01

    The 20th century saw some of the most important technological and scientific discoveries in the history of humankind. The space shuttle, the internet, and other modern advances changed society forever, and yet many students cannot imagine what life was like before these technologies existed. In the project described here, students take a firsthand…

  3. 1. Photocpy of early 20th century photograph, looking east, of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocpy of early 20th century photograph, looking east, of east facade of assembly building on Euclid Ave. Photo owned by the Cleveland Public Library. - Ford Motor Company, Cleveland Branch Assembly Plant, Euclid Avenue & East 116th Street, Cleveland, Cuyahoga County, OH

  4. 2. Photocopy of early 20th century photo, showing the Euclid ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of early 20th century photo, showing the Euclid Avenue facade of the branch assembly building. Photograph owned by the Cleveland Public Library. - Ford Motor Company, Cleveland Branch Assembly Plant, Euclid Avenue & East 116th Street, Cleveland, Cuyahoga County, OH

  5. Dancetime! 500 Years of Social Dance. Volume II: 20th Century. [Videotape].

    ERIC Educational Resources Information Center

    Teten, Carol

    This 50-minute VHS videotape is the second in a 2-volume series that presents 500 years of social dance, music, and fashion. It features dance and music of the 20th century, including; 1910s: animal dances, castle walk, apache, and tango; 1920s: black bottom and charleston; 1930s: marathon, movie musicals, big apple, and jitterbug; 1940s: rumba;…

  6. Retrospective on Educational Testing and Assessment in the 20th Century.

    ERIC Educational Resources Information Center

    Clarke, Marguerite M.; Madaus, George F.; Horn, Catherine L.; Ramos, Miguel A.

    2000-01-01

    Explores the growth of the U.S. testing industry since the 1900s. Discusses the technical developments that have encouraged the use of standardized testing and contributed to the growth of the testing industry. Attempts to quantify the expansion of the testing marketplace through the 20th century. Includes references. (CMK)

  7. 1. Photocopy of early 20th century rendering showing aerial veiw, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopy of early 20th century rendering showing aerial veiw, looking south. Rendering owned by the Crawford Auto-Aviation Museum, 10825 East Blvd., Cleveland, Ohio. - Peerless Motor Car Company, East Ninety-third Street & Quincy Avenue, Cleveland, Cuyahoga County, OH

  8. 2. Photocopy of early 20th century drawing, looking south from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of early 20th century drawing, looking south from the air. Drawing owned by the Crawford Auto-Aviation Museum, 10825 East Blvd., Cleveland, Ohio. - Peerless Motor Car Company, East Ninety-third Street & Quincy Avenue, Cleveland, Cuyahoga County, OH

  9. 4. Photocopy of early 20th century photo of the bridge. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Photocopy of early 20th century photo of the bridge. Donated to HAER for its collection at the Library of Congress; donation courtesy of the Erie Railroad Company. - Erie Railway, Moodna Creek Viaduct, Moodna Creek, Orrs Mill Road, Salisbury Mills, Orange County, NY

  10. Visual Preferences of Young School Children for Paintings from the 20th Century

    ERIC Educational Resources Information Center

    Kuscevic, Dubravka; Kardum, Goran; Brajcic, Marija

    2014-01-01

    The aim of this study was to investigate the differences of young school children in the visual preferences of paintings from the 20th century. The study was conducted at 4 elementary schools around Split, Croatia. A total of 200 children participated in the study, of which 87 were girls and 113 were boys aged 6-10 years. Visual preference testing…

  11. Blackness and Whiteness as Historical Forces in the 20th Century United States

    ERIC Educational Resources Information Center

    Greason, Walter

    2009-01-01

    At the core of the epistemology of black identity in the 20th century United States is the assertion that freedom is a human right, not a privilege to be earned. By the late 19th century, an ideology of racial uplift had emerged that revolved around four concepts--compassion, service, education, and a commitment to social and economic justice for…

  12. 10. Photocopy, WATER TOWERS, late 19th or early 20th century. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Photocopy, WATER TOWERS, late 19th or early 20th century. Original Photograph at State Historical Society of North Dakota, file No. TF899 - Fort Totten, 12 miles southwest of Devils Lake City off Route 57, Devils Lake, Ramsey County, ND

  13. From Card Catalogues to WebPACs: Celebrating Cataloguing in the 20th Century.

    ERIC Educational Resources Information Center

    Gorman, Michael

    This paper provides an overview of cataloging in the 20th century. Highlights include: (1) issues in 1901, including the emerging cooperative cataloging system and the work of Charles Ammi Cutter; (2) the 1908 code, i.e., "Catalog Rules: Author and Title Entries," published in British and American editions; (3) the Vatican rules, a code of rules…

  14. Modeling the impact of late 20th century stratospheric ozone changes: Sensitivity to different ozone forcing data sets and zonal asymmetry

    NASA Astrophysics Data System (ADS)

    Davis, S. M.

    2013-12-01

    Stratospheric ozone depletion in the Antarctic has profoundly influenced both stratospheric and tropospheric climate, and models lacking stratospheric ozone depletion poorly reproduce past Southern Hemisphere (SH) circulation change. Several studies have shown evidence that prescribing zonal-mean ozone in models leads to underestimation of SH change, and that the zonal asymmetry in ozone depletion has a large impact on the zonal-mean climate response. In this presentation we will show simulations from the NCAR Whole Atmosphere Community Climate Model (WACCM) forced with prescribed ozone fields to revisit the issue of whether it is possible to accurately reproduce late 20th century SH circulation change. In this presentation, we will demonstrate an enhanced SH circulation response in simulations with prescribed zonal-mean ozone from a new historical database that more accurately captures the depth of ozone depletion than databases previously used in the SPARC and CMIP5 assessments. We then compare this response from a 2D prescribed ozone field to a simulation using a prescribed 3D ozone field, and assess how well these simulations compare to observed changes seen in the Microwave Sounding Unit satellite temperature datasets and reanalysis.

  15. Global reconstructed daily storm surge levels from the 20th century reanalysis (1871-2010)

    NASA Astrophysics Data System (ADS)

    Cid, Alba; Camus, Paula; Castanedo, Sonia; Mendez, Fernando; Medina, Raul

    2015-04-01

    The study of global patterns of wind and pressure gradients, and more specifically, their effect on the sea level variation (storm surge), is a key issue in the understanding of recent climate changes. The local effect of storm surges on coastal areas (zones particularly vulnerable to climate variability and changes in sea level), is also of great interest in, for instance, flooding risk assessment. Studying the spatial and temporal variability of storm surges from observations is a difficult task to accomplish since observations are not homogeneous in time and scarce in space, and moreover, their temporal coverage is limited. The development of a global storm surge database (DAC, Dynamic Atmospheric Correction by Aviso, Carrère and Lyard, 2003) fulfils the lack of data in terms of spatial coverage, but not regarding time extent since it only includes last couple of decades (1992-2014). In this work, we propose the use of the 20CR ensemble (Compo et al., 2011) which spans from 1871 to 2010 to statistically reconstruct storm surge at a global scale and for a long period of time. Therefore, the temporal and spatial variability of storm surges can be fully studied and with much less effort than performing a dynamical downscaling. The statistical method chosen to carry out the reconstruction is based on multiple linear regression between an atmospheric predictor and the storm surge level at daily scale (Camus et al., 2014). The linear regression model is calibrated and validated using daily mean sea level pressure fields (and gradients) from the ERA-interim reanalysis and daily maxima surges from DAC. The obtained daily database of maximum daily surges has allowed us to estimate global trends at a centennial scale and analyse the effect of the changing climate on storm surges during the 20th century. Hence, this work improves the knowledge on historical storm-surge conditions and provides helpful information to the community concern on marine climate evolution and

  16. 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

  17. Surface solar radiation and hydrological cycle in 20th century China: sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Wild, M.

    2012-04-01

    The world, and China in particular, has seen a tremendous population growth and industrialization in the 20th century. These changes were accompanied, among others, by a substantial increase in aerosol emission. To learn more about associated consequences for the climate system we have carried out a comparatively large set of transient sensitivity studies with the global atmosphere only climate model ECHAM5-HAM, using aerosol emission data from NIES (National Institute of Environmental Studies, Japan) and prescribed, observation based sea surface temperatures (SSTs) from the Hadley Center. The sensitivity studies cover the period from 1870 to 2005 and comprise ensembles of simulations (up to 13 members per ensemble), which allow to address the role of different aerosol species, greenhouse gases, and prescribed sea surface temperatures. Here we analyze these simulation data with particular focus on surface solar radiation, temperature, and the hydrological cycle in China. Physical mechanisms able to explain the results will be discussed. We generally find the strongest effects in the east of the country, where urbanization and industrialization is strongest and emissions increased most. The decrease of surface solar radiation (SSR) under clear sky conditions reaches up to around -8 W / m2 per decade from 1950 to 1990. Comparable values are found for all sky conditions. Dimming ceases in the second half of the 1990s, when we even see a renewed increase in SSR in some regions. Overall, these findings are in line with observation based estimates. Modeled surface temperatures reflect the decrease in SSR but carry also a substantial SST signature. After remaining roughly constant from 1870 to 1900, we find modeled surface temperatures to increase by about 1 degree Celsius till 1950, then decrease again by -0.2 to -1.2 degree Celsius till 1990, before a renewed increase sets in. Precipitation decreases in our model results from 1950 to 2000 by up to 10% or 150 mm per year

  18. Responses of Multi-Aged Music Students to Mid-20th-Century Art Music: A Replication and Extension

    ERIC Educational Resources Information Center

    Madsen, Clifford K.; Geringer, John M.

    2015-01-01

    This investigation replicates previous research into K-12 students' responses to mid-20th-century art music. The study extends that research to include undergraduates and graduates as well as an additional group of graduate students who had taken a 20th-century music class. Children's responses showed remarkable consistency and indicated that…

  19. Impact of 20th Century Wars on the Development of Neurosurgery.

    PubMed

    Dowdy, Justin; Pait, T Glenn

    2016-01-01

    The treatment of neurosurgical casualties suffered during the wars of the 20th century had a significant impact on the formation and early growth of neurosurgery as a specialty. This chapter explores how the evolution of military tactics and weaponry along with the circumstances surrounding the wars themselves profoundly influenced the field. From the crystallization of intracranial projectile wound management and the formal recognition of the specialty itself arising from World War I experiences to the radical progress made in the outcomes of spinal-cord-injured soldiers in World War II or the fact that the neurosurgical training courses commissioned for these wars proved to be the precursors to modern neurosurgical training programs, the impact of the 20th century wars on the development of the field of neurosurgery is considerable. PMID:27035828

  20. Lunar and Planetary Robotic Exploration Missions in the 20th Century

    NASA Astrophysics Data System (ADS)

    Huntress, W. T., Jr.; Moroz, V. I.; Shevalev, I. L.

    2003-07-01

    The prospect of traveling to the planets was science fiction at the beginning of the 20th Century and science fact at its end. The space age was born of the Cold War in the 1950s and throughout most of the remainder of the century it provided not just an adventure in the exploration of space but a suspenseful drama as the US and USSR competed to be first and best. It is a tale of patience to overcome obstacles, courage to try the previously impossible and persistence to overcome failure, a tale of both fantastic accomplishment and debilitating loss. We briefly describe the history of robotic lunar and planetary exploration in the 20th Century, the missions attempted, their goals and their fate. We describe how this enterprise developed and evolved step by step from a politically driven competition to intense scientific investigations and international cooperation.

  1. Changes in the global freshwater N and P cycles over the 20th century

    NASA Astrophysics Data System (ADS)

    Beusen, Arthur; van Beek, Rens; Bouwman, Lex; Mogollón, José; Middelburg, Jack

    2016-04-01

    Dramatic world-wide changes occurred during the 20th century in both nutrient delivery and in-stream retention. In this paper, we use a combined nutrient-input, hydrology, in-stream nutrient retention model to quantitatively track the changes in the global freshwater N and P cycles over the 20th century. Global nutrient delivery almost doubled due to expanding agriculture and increasing wastewater discharge. Nutrient retention also increased by a factor of two as a result of the rapidly growing number of dams and reservoirs. This increase in nutrient retention could not balance the increase in nutrient delivery to rivers. River export to coastal seas increased during the 20th century from 19 to 37 Tg yr-1 of N and 2 to 4 Tg yr-1 of P. There are important differences in riverine N:P export ratios in various parts of the world resulting from the interplay of multiple processes and economic activities in different river basins. Increasing nutrient loading of freshwater systems is a threat to water quality. Furthermore, the global river export increase in the molar N:P ratio during recent decades may affect the ecology within both the river basins and the coastal system. This ratio change may be driven by the recent stagnation of P fertilizer use in most industrialized countries, in comparison to the ever increasing N fertilizer use.

  2. The process of Danish nurses' professionalization and patterns of thought in the 20th century.

    PubMed

    Beedholm, Kirsten; Frederiksen, Kirsten

    2015-06-01

    In this article, we address how the professionalization process is reflected in the way Danish nursing textbooks present 'nursing' to new members of the profession during the 20th century. The discussion is based on a discourse analysis of seven Danish textbooks on basic nursing published between 1904 and 1996. The analysis was inspired by the work of Michel Foucault, in particular the concepts of rupture and rules of formation. First, we explain how the dominating role of the human body in nursing textbooks disappears in the mid-20th century. This transformation can of course be attributed to changes in tasks and responsibilities for nurses or to the implementation of increasing amounts of knowledge and theories from other disciplines than medicine into the nurses' knowledge base. However, inspired by Foucault, we consider these historical changes to be the conditions of possibilities and not causes. The second part of the analysis shows that along with 'the disappearance of the body', a second discursive change appears: the role of doctors and medicine changes fundamentally from about mid-20th century. Finally, we argue that this discursive reorganization enabling new patterns of thought to emerge was driven by a professional interest in describing nursing as an independent profession. PMID:25238323

  3. Catholic Nursing Sisters and Brothers and Racial Justice in Mid-20th-Century America

    PubMed Central

    Wall, Barbra Mann

    2009-01-01

    This historical article considers nursing’s work for social justice in the 1960s civil rights movement through the lens of religious sisters and brothers who advocated for racial equality. The article examines Catholic nurses’ work with African Americans in the mid-20th century that took place amid the prevailing social conditions of poverty and racial disempowerment, conditions that were linked to serious health consequences. Historical methodology is used within the framework of “bearing witness,” a term often used in relation to the civil rights movement and one the sisters themselves employed. Two situations involving nurses in the mid-20th century are examined: the civil rights movement in Selma, Alabama, and the actions for racial justice in Chicago, Illinois. The thoughts and actions of Catholic sister and brother nurses in the mid-20th century are chronicled, including those few sister nurses who stepped outside their ordinary roles in an attempt to change an unjust system entirely. PMID:19461224

  4. Sea Level did not Accelerate in the Last Quarter of the 20th Century

    NASA Astrophysics Data System (ADS)

    Galvin, C.

    2004-12-01

    The Permanent Service for Mean Sea Level (PSMSL)collects quality-controlled sea levels from tide gages on all seas, and tabulates them at www.pol.ac.uk/psmsl/psmsl(underline)individual(underline)stations.html. I examined annual average sea levels (Ra in column 6) for generally open-coast tide gages having data at the years defining quarter points in the 20th century: 1900, 1925, 1950, 1975, 2000. Gages lacking data for a given date, say 1975, were assumed to qualify if they had data for one year, plus or minus, of the missing data, i. e., for 1974 or 1976 in this example. This examination of data from gages on all seas identified 54 gages with data for the last three of the five dates, which included 26 gages with data for the last four of the five dates, which included 7 gages with data for all five dates. This means that sea-level change during the last quarter (Q4) of the 20th century could be compared at 54 sites with sea-level change in Q3, at 26 sites with sea- level change in Q2, and at 7 sites with sea-level change in Q1, providing 87 tests of the widely reported acceleration in rate of sea-level rise at the end of the 20th century. If sea level is rising at an accelerating rate, then sea-level rise during Q4 should almost always exceed sea-level rises in Q1, Q2, and Q3 of the 20th century. Of the 87 tests, 44 showed more sea-level rise in Q4, and 43 showed less sea-level rise in Q4, compared to the earlier quarters. Thus there is no evidence for an accelerating rise in sea level at the end of the 20th century from these quality-controlled data. The data do indicate that sea-level changes are synchronized over long reaches of shoreline (Sturges, 1990), and sites where gages are imbedded in deposits of clastic sediment have higher apparent sea-level rise attributable to sediment compaction. Beach erosion on the East Coast of the U.S. is widely attributed to the acceleration of sea-level rise, yet all 8 long-term gages at this coast show significantly LESS

  5. Disastrous floods and landslides in Portugal in the 20th century

    NASA Astrophysics Data System (ADS)

    Quaresma, Ivânia; Zêzere, José Luis

    2010-05-01

    The record and analysis of statistical information on disaster occurrence, impacts and losses have been made worldwide in recent years. The development of natural disasters databases is crucial for risk management purposes, because it allows improving systems of indicators on disaster risk and vulnerability at national and sub-national scales. During the last century, Portugal was affected by several destructive natural disasters, namely of hydrologic (floods) and geomorphologic (landslides) origin. However, only recently risk prevention and management was assumed to be a national priority by the Portuguese Government. The basic information on past floods and landslides that occurred in Portugal is disperse and incomplete, and this is a shortcoming for the implementation of effective disaster mitigation measures, particularly when it is expectable an increase of frequency, magnitude, dimension and complexity of the hydro-geomorphologic phenomena resulting from climate change. In this work we present a preliminary assessment of hydro-geomorphologic disasters occurred in Portugal during the 20th century, based on the systematic survey of daily national newspapers. We included into a database those floods and landslides that produced, alternatively, dead people, injured people, missing people, evacuated and homeless. A total of 937 hydro-geomorphologic events were registered. In addition to physical and material damages, these events produced economic losses amounting to millions Euros. Our attention will focus on the geographic distribution and the temporal dimension of disastrous floods and landslides occurred in Portugal, and the temporal trends of hydro-geomorphologic disasters will be presented. The preliminary results shown that disastrous floods and landslides have been more frequent on the most populated regions of Portugal: the metropolitan areas of Lisbon and Oporto. In addition, data shows that disastrous hydrologic and geomorphologic phenomena were more

  6. The 20th Century evolution of energy budgets and meridional transports in two AMIP-like experiments

    NASA Astrophysics Data System (ADS)

    Lembo, Valerio; Folini, Doris; Wild, Martin; Lionello, Piero

    2016-04-01

    The 20th century evolution and spatial patterns of the Top-of-Atmosphere (TOA), atmospheric, and surface energy budgets (EB) are investigated in this work. These are computed as the balance between the radiative and heat fluxes at the TOA and at the surface. Total, atmospheric and oceanic meridional energy transports are computed from the EBs. Two AMIP-like ensemble simulations are considered: Integrated Forecast System (IFS) simulations of the ERA-20CM experiment, and ECHAM5-HAM model simulations. With the latter, additional sensitivity experiments are carried out by constraining either Sea-Surface Temperatures (SST) and Sea-Ice Cover (SIC) or aerosol concentrations to climatological values. The recent decades estimates of the EB are in reasonable agreement in the two models, while they are not for what concerns the global scale evolution. Particularly, in the 1970s ERA-20CM shows a fast transition from negative to positive EBs at Top of Atmosphere (TOA) that is not found in ECHAM5-HAM. The impact of aerosols, as evidenced by the sensitivity experiments with ECHAM5-HAM, is seen to set up an inter-hemispheric gradient in the TOA and surface budget after 1960. This is also reflected by an increased total poleward transport in the Northern Hemisphere and decreased in the Southern Hemisphere. This feature is not found in ERA-20CM. SST variations do not seem to induce long-term variations in the patterns of TOA budget and related total meridional transport. Nevertheless most of the surface and atmospheric budget and transport inter-annual variability is attributable to the evolution of SST, and much more agreement is observed among the two models in this respect. Reference: Lembo V, Doris F, Martin W, and Lionello P (2015) Energy budgets and transports: global evolution and spatial patterns during the 20th Century as estimated in two AMIP-like experiments, Clim. Dyn., subm.

  7. An Eight-Century High-Resolution Paleoclimate Record From the Cariaco Basin: Baseline Variability and the 20th Century

    NASA Astrophysics Data System (ADS)

    Black, D. E.; Thunell, R. C.; Kaplan, A.; Tappa, E. J.; Peterson, L. C.

    2007-12-01

    The Cariaco Basin, Venezuela is well-positioned to record a detailed history of surface ocean changes along the southern margin of the Caribbean and the tropical Atlantic. Varved, high deposition rate sediments deposited under anoxic conditions and an abundance of well-preserved microfossils result in one of the few marine records capable of preserving evidence of interannual- to decadal-scale climate variability in the tropical Atlantic. Here we present Mg/Ca and stable oxygen isotope data with sub-decadal resolution derived from sediments deposited over the last 800 years. Mg/Ca measured on the planktic foraminifer Globigerina bulloides from a Cariaco Basin sediment core strongly correlates with spring (March-May) instrumental SSTs between AD 1870 and 1990. The long-term record displays a surprising amount of variability for a tropical location. The temperature swings are not necessarily related to local upwelling variability, but instead represent wider conditions in the Caribbean and western tropical Atlantic. The Mg/Ca-SST record also captures the decadal and multidecadal variability observed in global land and sea surface temperature anomalies, and correlates with Atlantic tropical storm and hurricane frequency over the late-19th and 20th centuries. On average, 20th century temperatures are not the warmest in the entire record, but they do show the largest increase in magnitude and fastest rate of SST change over the last eight hundred years. Stable oxygen isotope data also correlate well with instrumental SSTs, but not over the full instrumental record. Poor correlations with early instrumental SST data suggest a salinity overprint. However, reconstructing δ- water variability using combined Mg/Ca and δ18O data is not straightforward as the δ- water/salinity relationship varies seasonally in the Cariaco Basin. Comparisons with percent titanium data suggest intervals of both local and regional surface salinity changes over the length of the record.

  8. Presence and possible cause of periodicities in 20th-century extreme coastal surge: Belfast Harbour, Northern Ireland

    NASA Astrophysics Data System (ADS)

    Orford, Julian; Murdy, Joanne

    2015-10-01

    Identifying 20th-century periodic coastal surge variation is strategic for the 21st-century coastal surge estimates, as surge periodicities may amplify/reduce future MSL enhanced surge forecasts. Extreme coastal surge data from Belfast Harbour (UK) tide gauges are available for 1901-2010 and provide the potential for decadal-plus periodic coastal surge analysis. Annual extreme surge-elevation distributions (sampled every 10-min) are analysed using PCA and cluster analysis to decompose variation within- and between-years to assess similarity of years in terms of Surge Climate Types, and to establish significance of any transitions in Type occurrence over time using non-parametric Markov analysis. Annual extreme surge variation is shown to be periodically organised across the 20th century. Extreme surge magnitude and distribution show a number of significant cyclonic induced multi-annual (2, 3, 5 & 6 years) cycles, as well as dominant multi-decadal (15-25 years) cycles of variation superimposed on an 80 year fluctuation in atmospheric-oceanic variation across the North Atlantic (relative to NAO/AMO interaction). The top 30 extreme surge events show some relationship with NAO per se, given that 80% are associated with westerly dominant atmospheric flows (+ NAO), but there are 20% of the events associated with blocking air massess (- NAO). Although 20% of the top 30 ranked positive surges occurred within the last twenty years, there is no unequivocal evidence of recent acceleration in extreme surge magnitude related to other than the scale of natural periodic variation.

  9. Adriatic and Black Sea level in the 20th century and projection to the end of the 21st century.

    NASA Astrophysics Data System (ADS)

    Scarascia, Luca; Lionello, Piero

    2015-04-01

    Adriatic and Black Sea are semi-enclosed basins characterized by densely populated coasts, industrial compounds and a rich cultural and historical heritage. It appears to be crucial, for the management and the protection of their coastlines, to understand how much they will be impacted by the global sea level (SL) rise, projected by the end of this century. The aim of this work is to develop a method that allows to estimate to which extent the SL of the two basins will depart from the mean global level. The future evolution of global sea level is not a meaningful indicator at this regional scale and past deviations, due to local factors of the Adriatic and Black Sea levels from the global one, have been observed. The Adriatic Sea is the basin of the Mediterranean Sea best covered by past SL observations. In fact, for the Adriatic Sea is possible to obtain, by statistical method based on PCA and Least square Method, a seamless and long time series (from 1900 to 2009) using records of 7 mareographic stations located along the Italian and Croatian coasts (from PSMSL database). Satellite data of SL are available for the whole Mediterranean from 1993 to 2012 and they show a very high correlation (rho > 0.9) with Adriatic time series based on mareographic records. The SL time series of the 20th century in the Black Sea is computed using data of 4 stations, which are available in the PSMSL (Permanent Service for Mean Sea Level) archive, located on the north-east coast. This time series shows a lower correlation (rho about 0.5) with satellite data than in the case of Adriatic Sea. Further it shows a higher interannual variability. All the time series are considered after the subtraction of the Inverse Barometer (IB) effect. A statistical approach, based on a multivariate linear regression model, is used to investigate the link between SL anomaly, computed as the difference between the regional SL and global SL, and three large scale climate variables (sea level pressure

  10. Assessing how seasonal hydrological balance has changed during the warming 20th century in the montane forests of Southeast Asian monsoon region using a stable isotope dendroclimatology approach

    NASA Astrophysics Data System (ADS)

    Zhu, M.; Stott, L. D.

    2010-12-01

    Tropical montane forests act as water catchment and host of biodiversity in the Southeast Asian monsoon region, and understanding how their hydrological conditions change with global warming is vitally important. Global climate model simulations project enhanced moisture cycle in the tropics, which would cause stronger summer monsoon precipitations, but on the other hand the adiabatic lapse rate would be shifted towards a moister condition (amplification of warming at high elevation), inhibiting dry season orographic lifting cloud/fog formation (lifting cloud base hypothesis), enhancing evapo-transpiration, and leading to a net moisture loss during winter dry season. In this study, we have attempted to investigate how the seasonal moisture balance in Southeast Asia has evolved in response to these influences through the 20th century using the oxygen isotopic composition (δ18O) of subannual tree cellulose samples extracted from the annual rings of pine trees that grow in Doi Chiang Dao, a limestone mountain in northern Thailand. At this location the δ18O of cellulose exhibits distinctive annual cycles of up to 12‰, which is primarily a reflection of both the so-called ‘isotope amount effect’ that is associated with the strong monsoon precipitation during summer wet season and the moisture availability from different sources during winter dry season. We have demonstrated that tree cellulose δ18O could be used as a proxy for regional monsoon strength by showing that the annual mean cellulose δ18O correlate significantly with All India Rainfall, Webster-Yang monsoon index, as well as with both local and regional monsoon precipitation. ENSO is the dominant influence on interannual rainfall variability and this is well expressed in the interannual cellulose δ18O record. Using a 21-year moving window correlation analysis we find a weakening of ENSO influence after 1980, coinciding with the most rapid atmospheric warming. We expect to analyze older trees to

  11. Potential forest fire danger over Northern Eurasia: Changes during the 20th century

    NASA Astrophysics Data System (ADS)

    Sherstyukov, B. G.; Razuvaev, V. N.; Groisman, P. Y.; Knight, R. W.; Enloe, J. G.

    2004-12-01

    Significant climatic changes over Northern Eurasia during the 20th century have been reflected in numerous variables of economic, social, and ecological interests, including the natural frequency of forest fires. For the former USSR, we are now using the Global Daily Climatology Network (Gleason et al. 2002) and a new Global Synoptic Data Network archive, GSDN, created jointly by NCDC an RIHMI. Data from these archives are employed to estimate systematic changes in indices used in the United States and Russia to assess potential forest fire danger. Within the boundaries of the former USSR, each of the archives, GHCN and GSDN, includes more than 2100 stations with only approximately 1500 of them having sufficiently long meteorological time series suitable for participation in our analyses. We use three indices: (1) Keetch-Byram Drought Index, (KBDI; this index uses only daily data on maximum temperature and precipitation and is developed and widely used in the United States); (2) Modified Nesterov, and (3) Zhdanko Indices (these indices are developed and widely used in Russia; their computation requires synoptic daytime data on temperature and humidity and daily precipitation and snow on the ground). Analyses show that after calibration, time series of the days with increased potential forest fire danger constructed using each of these three indices (a) are well correlated and (b) deliver similar conclusions about systematic changes in the weather conditions conducive to forest fires. Specifically, over the entire Eastern half of Northern Eurasia (Siberia and the Russian Far East) we found a statistically significant increase in indices that characterize the weather conditions conducive to forest fires. These areas coincide with the areas of most significant warming during the past several decades south of the Arctic Circle. West of the Ural Mountains, the same indices show a steady decrease in the frequency of the "dry weather summer days" during the past sixty

  12. [Anti-positivist inspiration in European medical historiography in the 20th century].

    PubMed

    Płonka-Syroka, Bozena

    2002-01-01

    The article presents the most important anti-positivist (the neo-romantic, socio-cultural and relativistic) currents in 20th century European medical historiography. The author discusses the genesis of the anti-positivist opposition in the medical historiography, starting with a presentation of the main points of the positivist programme, and shows the reasons behind the earlier broad reception of this programme by medical historians from the medical profession. The author attributes the emergence of an anti-positivist opposition in this milieu mainly to the medical progress which occurred in the first half of the 20th century and which induced some doctors, engaged in research into medical history, to reject the positivist model of teaching and replace it wit another. This factor played a leading role in the formation of the socio-cultural and relativist currents. According to the author, the second important factor in the birth of this opposition is the 20th century progress in the methodology of historical research, which freed itself from the constraints of positivist scientism as the only acceptable method of interpreting facts. The author also discusses the socio-cultural and political conditions which led to the formation and spread of the neo-romantic movement solely in Germany. The article presents the programme principles and the most important representatives of anti-positivist currents in European (mainly German) and the circumstances behind the reception of each current by the community of medical historians, and presents the development prospects of Polish medical historiography on the treshold of the 20th and 21st centuries, in connection with the research into this field of science undertaken by a large and continuously growing number of university-educated researchers. PMID:12934578

  13. Why does FGOALS-gl reproduce a weak Medieval Warm Period but a reasonable Little Ice Age and 20th century warming?

    NASA Astrophysics Data System (ADS)

    Guo, Zhun; Zhou, Tianjun

    2013-11-01

    To understand the strengths and limitations of a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice (FGOALS-gl) to simulate the climate of the last millennium, the energy balance, climate sensitivity and absorption feedback of the model are analyzed. Simulation of last-millennium climate was carried out by driving the model with natural (solar radiation and volcanic eruptions) and anthropogenic (greenhouse gases and aerosols) forcing agents. The model feedback factors for (model sensitivity to) different forcings were calculated. The results show that the system feedback factor is about 2.5 (W m-2) K-1 in the pre-industrial period, while 1.9 (W m-2) K-1 in the industrial era. Thus, the model’s sensitivity to natural forcing is weak, which explains why it reproduces a weak Medieval Warm Period. The relatively reasonable simulation of the Little Ice Age is caused by both the specified radiative forcing and unforced linear cold drift. The model sensitivity in the industrial era is higher than that of the pre-industrial period. A negative net cloud radiative feedback operates during whole-millennial simulation and reduces the model’s sensitivity to specified forcing. The negative net cloud radiative forcing feedback under natural forcing in the period prior to 1850 is due to the underestimation (overestimation) of the response of cloudiness (in-cloud water path). In the industrial era, the strong tropospheric temperature response enlarges the effective radius of ice clouds and reduces the fractional ice content within cloud, resulting in a weak negative net cloud feedback in the industrial period. The water vapor feedback in the industrial era is also stronger than that in the pre-industrial period. Both are in favor of higher model sensitivity and thus a reasonable simulation of the 20th century global warming.

  14. Alfred Werner's role in the mid-20th century flourishing of American inorganic chemistry.

    PubMed

    Labinger, Jay A

    2014-01-01

    The development of organic and physical chemistry as specialist fields, during the middle and end of the 19th century respectively, left inorganic behind as a decidedly less highly regarded subfield of chemistry. Despite Alfred Werner's groundbreaking studies of coordination chemistry in the early 20th century, that inferior status remained in place - particularly in the US - until the 1950s, when the beginnings of a resurgence that eventually restored its parity with the other subfields can be clearly observed. This paper explores the extent to which Werner's heritage - both direct, in the form of academic descendants, and indirect - contributed to those advances. PMID:24983802

  15. Dr Charles Thomas Jackson's (1805-80) life after death: the 20th century mythology.

    PubMed

    Patterson, Richard

    2007-08-01

    References to Dr Charles Thomas Jackson in 20th century anaesthesia literature and biographical dictionaries and encyclopedias emphasize his maniacal insanity and its relation to his usurpations of the discoveries of others, including the controversy with William TG Morton concerning the honour of the discovery of surgical anaesthesia. In 1873, seven years before his death, he experienced sudden collapse and paralysis requiring hospitalization. Seminal 19th century brain research before his hospitalization correlated the signs and symptoms of his illness with pathology found at his autopsy. PMID:17641787

  16. Assortative mating and differential fertility by phenotype and genotype across the 20th century.

    PubMed

    Conley, Dalton; Laidley, Thomas; Belsky, Daniel W; Fletcher, Jason M; Boardman, Jason D; Domingue, Benjamin W

    2016-06-14

    This study asks two related questions about the shifting landscape of marriage and reproduction in US society over the course of the last century with respect to a range of health and behavioral phenotypes and their associated genetic architecture: (i) Has assortment on measured genetic factors influencing reproductive and social fitness traits changed over the course of the 20th century? (ii) Has the genetic covariance between fitness (as measured by total fertility) and other traits changed over time? The answers to these questions inform our understanding of how the genetic landscape of American society has changed over the past century and have implications for population trends. We show that husbands and wives carry similar loadings for genetic factors related to education and height. However, the magnitude of this similarity is modest and has been fairly consistent over the course of the 20th century. This consistency is particularly notable in the case of education, for which phenotypic similarity among spouses has increased in recent years. Likewise, changing patterns of the number of children ever born by phenotype are not matched by shifts in genotype-fertility relationships over time. Taken together, these trends provide no evidence that social sorting is becoming increasingly genetic in nature or that dysgenic dynamics have accelerated. PMID:27247411

  17. Assortative mating and differential fertility by phenotype and genotype across the 20th century

    PubMed Central

    Laidley, Thomas; Belsky, Daniel W.; Fletcher, Jason M.; Boardman, Jason D.; Domingue, Benjamin W.

    2016-01-01

    This study asks two related questions about the shifting landscape of marriage and reproduction in US society over the course of the last century with respect to a range of health and behavioral phenotypes and their associated genetic architecture: (i) Has assortment on measured genetic factors influencing reproductive and social fitness traits changed over the course of the 20th century? (ii) Has the genetic covariance between fitness (as measured by total fertility) and other traits changed over time? The answers to these questions inform our understanding of how the genetic landscape of American society has changed over the past century and have implications for population trends. We show that husbands and wives carry similar loadings for genetic factors related to education and height. However, the magnitude of this similarity is modest and has been fairly consistent over the course of the 20th century. This consistency is particularly notable in the case of education, for which phenotypic similarity among spouses has increased in recent years. Likewise, changing patterns of the number of children ever born by phenotype are not matched by shifts in genotype–fertility relationships over time. Taken together, these trends provide no evidence that social sorting is becoming increasingly genetic in nature or that dysgenic dynamics have accelerated. PMID:27247411

  18. Historical perspective: Arthur Kornberg, a giant of 20th century biochemistry.

    PubMed

    Lehman, I Robert

    2008-06-01

    For physics, the period from the beginning to the middle of the 20th century was one of great scientific excitement and revolutionary discovery. The analogous era for biochemistry, and its offspring, molecular biology, was the second half of the 20th century. One of the most important and influential leaders of this scientific revolution was Arthur Kornberg. The DNA polymerase, which he discovered in 1955 and showed to have the remarkable capacity to catalyze the template-directed synthesis of DNA, contributed in major ways to the present-day understanding of how DNA is replicated and repaired, and how it is transcribed. The discovery of DNA polymerase also permitted the development of PCR and DNA sequencing, upon which much of modern biotechnology is based. Kornberg's studies of DNA replication, which spanned a period of nearly 30 years, culminated in a detailed biochemical description of the mechanism by which a chromosome is replicated. The final years of Kornberg's life were devoted to the study of polyphosphate, which he was convinced had a crucial role in cellular function. PMID:18467101

  19. Life expectancy of the 20th century Venda: a compilation of skeletal and cemetery data.

    PubMed

    L'Abbé, E N; Steyn, M; Loots, M

    2008-01-01

    Little information is available on the 20th century mortality rates of rural black South African groups, such as the Venda. The purpose of this study was to apply abridged life tables in order to estimate life expectancy from both skeletal remains and death registry information of modern South African communities. Comparisons were also made with prehistoric and contemporary groups as a means to better evaluate life expectancy for this time period. The sample consisted of 160 skeletons of known Venda origin and burial registry information for 1364 black South Africans from the Rebecca Street and Mamelodi Cemeteries in Pretoria, South Africa. Standard anthropological techniques were applied to determine sex and estimate age from the skeletal remains. The stationary and non-stationary life table models were used to analyse the data. A high rate of child mortality, low juvenile and adult mortality with a steady increase in mortality after the age of 30 years was observed for both the Venda and the cemetery samples. Throughout the 20th century, life expectancy was shown to increase for black South Africans. However, due to the widespread HIV infection/AIDS of the 21st century, infant and young adult mortality rates continue to rise at such a speed that the decline in mortality seen for South Africans in the last 50 years will most likely to be lost in the next decade due to this disease. PMID:18555996

  20. The decline of winter monsoon velocity in the South China Sea through the 20th century: Evidence from the Sr/Ca records in corals

    USGS Publications Warehouse

    Liu, Yajing; Peng, Z.; Chen, T.; Wei, G.; Sun, W.; Sun, R.; He, J.; Liu, Gaisheng; Chou, C.-L.; Zartman, R.E.

    2008-01-01

    A modern massive Porites coral was collected from the Longwan Bay (19??20???N, 110??39???E) on the east coast of the Hainan Island, China. The coral was sectioned vertical to the growth axis into discs of double density-bands representing annual growth. The samples were analyzed for the Sr/Ca ratio by inductively coupled plasma atomic emission spectrometry. The history of winter sea-surface temperature (SST) is reconstructed using the Sr/Ca ratio in winter bands of corals. The winter SST at Xisha in the middle of the South China Sea (SCS) is weakly correlated with the instrument-measured winter monsoon velocity (WMV) with a correlation coefficient of 0.19. The winter SST data from corals at Longwan Bay, Hainan, in the northern SCS are moderately correlated with the WMV (r = 0.40). Interestingly we found that the difference of winter SSTs between the two sites (Xisha and Longwan Bay, Hainan) (the X-H index) is significantly negatively correlated with the WMV (r = - 0.73). This negative correlation may be related to the intrusion of the warm Kuroshio Current into the SCS through the Luzon Strait promoted by the strong northeastern monsoon winds in the winter. Using the relationship between our coralline data and observed WMV, the calculated winter monsoon velocity (WMVc) was obtained for 87??years. This data set in combination with the instrument-measured data between 1993 and 1998 generate a record of WMVc for a period of 93??years from 1906 to 1998. The WMVc in the 20th century shows significant interannual and decadal variability with a trend of persistent decline in the whole 20th century at the rate of decrease of - 0.02 (m/s)/a. The lowest wind velocity occurred during the last two decades of the 20th century. The WMVc has decreased significantly by about 30% from the early to the late of 20th century. The 20th century decline of winter monsoon velocity evidenced from the SCS coral records is consistent with the atmosphere-ocean general circulation models

  1. Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Model Biases Using data Assimilation

    SciTech Connect

    Sumant Nigam

    2013-02-05

    These five publications are summarized: Key role of the Atlantic Multidecadal Oscillation in 20th century drought and wet periods over the Great Plains; A Sub-Seasonal Teleconnection Analysis: PNA Development and Its Relationship to the NAO; AMO's Structure and Climate Footprint in Observations and IPCC AR5 Climate Simulations; The Atlantic Multidecadal Oscillation in 20th Century Climate Simulations: Uneven Progress from CMIP3 to CMIP5; and Tropical Atlantic Biases in CCSM4.

  2. Systematic recover of long high-resolution rainfall time series recorded by pluviographs during the 20th century.

    NASA Astrophysics Data System (ADS)

    Delitala, Alessandro M. S.; Deidda, Roberto; Mascaro, Giuseppe; Piga, Enrico; Querzoli, Giorgio

    2010-05-01

    During most of the 20th century, precipitation has been continuously measured by means of the so-called "pluviographs", i.e. rain gauges including a mechanical apparatus for continuously recording the depth of water from precipitation on specific strip charts, usually on a weekly basis. The signal recorded on such strips was visually examined by trained personnel on a regular basis, in order to extract the daily precipitation totals and the maximum precipitation intensities over short periods (from a few minutes to hours). The rest of the high-resolution information contained in the signal was usually not extracted, except for specific cases. A systematic recovering of the entire information at high temporal resolution contained in these precipitation signals would provide a fundamental database to improve the characterization of historical rainfall climatology during the previous century. The Department of Land Engineering of the University of Cagliari has recently developed and tested an automatic software, based on image analysis techniques, which is able to acquire the scanned images of the pluviograph strip charts, to automatically digitise the signal and to produce a digital database of continuous precipitation records at the highest possible temporal resolution, i.e. 5 to 10 minutes. Along with that, a significant amount of daily precipitation totals from the late 19th and the 20th century, either elaborated from pluviograph strip charts or simply derived from bucket rain gauges, still exists in paper form, but it has never been digitalized. Within a project partly-funded by the Operational Programme of the European Union "Italia-Francia Marittimo", the Regional Environmental Protection Agency of Sardinia and the University of Cagliari will recover both the high-resolution rainfall signals and the older time series of daily totals recorded by a large number of pluviographs belonging to the historical monitoring networks of the island of Sardinia. Such data

  3. A brief history of 20th century dam construction and a look into the future

    NASA Astrophysics Data System (ADS)

    van de Giesen, Nick

    2010-05-01

    In this presentation, an overview is given of global dam building activities in the 20th century. Political, economical and hydrological factors shaped the building of large dams. The development of the relations between these three factors and dam building over time is examined. One can argue whether or not history is simply "one damn thing after another" but the second half of the 20th century suggests that history is at least reflected by the construction of one dam after another. The financial crisis of the 1930's started the first construction wave of large hydropower dams in the United States. This wave continued into the Second World War. During the Cold War, the weapon race between the USA and USSR was accompanied by a parallel neck-and-neck race in dam construction. By the 1970's, dam construction in the USA tapered off, while that in the USSR continued until its political disintegration. In China, we see two spurts in dam development, the first one coinciding with the disastrous Great Leap Forward and the second with the liberalization of the Chinese economy after the fall of the Berlin Wall. Economic and political events thus shaped to an important extent decisions surrounding the construction of large dams. Clearly, there are some hydrological prerequisites for the construction of dams. The six largest dam building nations are USSR, Canada, USA, China, Brazil, and India, all large countries with ample water resources and mountain ranges. Australia has relatively little reservoir storage for the simple fact that most of this country is flat and dry. A few countries have relatively large amounts of reservoir storage. Especially Uganda (Owens Falls), Ghana (Akosombo), and Zimbabwe (Kariba) are examples of small countries where gorges in major rivers were "natural" places for large dams and reservoirs to be built early on. It seems that, deserts aside, the average potential storage capacity lies for most continents around 10 cm or about 50% of the total

  4. Determination and characterization of 20th century global sea level rise

    NASA Astrophysics Data System (ADS)

    Kuo, Chung-Yen

    In this study, we provide a determination of the 20th Century (1900--2002) global sea level rise, the associated error budgets, and the quantifications of the various geophysical sources of the observed sea level rise, using data and geophysical models. We analyzed significant geographical variations of the global sea level including those caused by the steric component (heat and salinity) in the ocean, and the self-gravitational signal as a result of ice sheets melting, including the effects of glacial isostatic adjustment (GIA) since the Pleistocene. In particular, relative sea level data from long-term (longest is 150 year records) and over 600 tide gauge sites globally from PSMSL and other sources, and geocentric sea level data from multiple satellite altimetry (1985--2005) have been used to determine and characterize 20th century global sea level rise. Altimeter and selected tide gauge sea level data have been used for the 20th century sea level determination, accounting for relative biases between the altimeters, effects of sea level corresponding to oceanic thermal expansion, vertical motions affecting tide gauge measurements, self gravitations, and barotropic ocean response. This study is also characterized by the roles of the polar ocean in the global sea level study and addressing the question whether there is a detectable sea level rise acceleration during the last decade. Vertical motions have been estimated by combining geocentric sea level measurements from satellite altimetry (TOPEX/POSEIDON) and long-term relative (crust-fixed) sea level records from global tide gauges using the Gauss-Markov (GM) model with stochastic constraints. The study provided a demonstration of improved vertical motion solutions in semi-enclosed seas and lakes, including Fennoscandia and the Great Lakes region, showing excellent agreement with independent GPS observed radial velocities, or with predictions from GIA models. In general, the estimated uncertainty of the observed

  5. Determination of droughts and high floods of the Bermejo River (Argentina) based on documentary evidence (17th to 20th century)

    NASA Astrophysics Data System (ADS)

    Prieto, M. R.; Rojas, F.

    2015-10-01

    This study reconstructs a series of droughts and high flow volumes of the Bermejo River from the 17th to 20th century based on a content analysis of historic documentary evidence, which is calibrated with instrumental climate data. The historic data series shows an increase in the frequency of extraordinarily high waters beginning in the 19th century and a significant decrease in extreme droughts beginning in 1890. The data are compared to variations in the Mendoza River for the same period, which show that there was a long-standing lack of correlation between the rivers.

  6. Changing Polygenic Penetrance on Phenotypes in the 20(th) Century Among Adults in the US Population.

    PubMed

    Conley, Dalton; Laidley, Thomas M; Boardman, Jason D; Domingue, Benjamin W

    2016-01-01

    This study evaluates changes in genetic penetrance-defined as the association between an additive polygenic score and its associated phenotype-across birth cohorts. Situating our analysis within recent historical trends in the U.S., we show that, while height and BMI show increasing genotypic penetrance over the course of 20(th) Century, education and heart disease show declining genotypic effects. Meanwhile, we find genotypic penetrance to be historically stable with respect to depression. Our findings help inform our understanding of how the genetic and environmental landscape of American society has changed over the past century, and have implications for research which models gene-environment (GxE) interactions, as well as polygenic score calculations in consortia studies that include multiple birth cohorts. PMID:27456657

  7. The history of blood transfusion prior to the 20th century--part 2.

    PubMed

    Learoyd, P

    2012-12-01

    Although there are a number of descriptions of 'blood infusion' in antiquity, it was the publication of the discovery of the circulation of blood in 1628 by William Harvey and the work of Christopher Wren and Robert Boyle in 1663 on the infusion of different materials into dogs that paved the way to the possible practical attempts at actual blood transfusion. Although these early experiments, principally by Richard Lower in England and Jean Denis in France provided valuable information regarding inter-species incompatibility and the problems of blood coagulation, it was not until the work of James Blundell in the early part of the 19th century that blood transfusion was used as a means of blood replacement. However, blood transfusion was not to become an accepted therapeutic possibility until the discovery of practical anticoagulation and the ABO blood groups at the start of the 20th century. PMID:23016954

  8. A personal retrospective on the second half of the 20th century.

    PubMed

    Nicholas Leibovic, K

    2013-06-01

    During the Second World War scientists and engineers were involved as never before in all technical phases of the war effort. It included intelligence, logistics and large scale automated computation. Much of this required team work which led to the adoption of interdisciplinary perspectives and found expression after the war in new fields of enquiry such as cybernetics, biophysics and artificial intelligence. While Europe was recovering from its devastation, the United States entered an unprecedented age of prosperity beginning in the 1940s and 50s. The political and budgetary environment was favorable for scientific research and it was felt in Europe as well as the U.S.A. I discuss some of these conditions and the figures associated with the work that became the foundation for advances throughout the second half of the 20th century and conclude with a few observations on quantitative neuroscience and the problem of representation. PMID:23313751

  9. Transformations in understanding the health impacts of air pollutants in the 20th century

    NASA Astrophysics Data System (ADS)

    Brimblecombe, P.

    2009-02-01

    The transformations of air pollution in the 20th century are well known. The century opened with urban atmospheres polluted by the combustion products of burning coal: smoke and sulfur dioxide. At the millennium these pollutants had almost vanished, replaced by the pollutants, both primary and secondary, a function of fossil-fuelled vehicles. However transitions in terms of health outcomes have been equally dramatic. Fine particulate matter causes notable cardiovascular problems such as increased incidence of stroke and heart attack, although the mechanism remains somewhat unclear. Cancer inducing air pollutants remain a concern, but in addition more recently there has been a rising interest in the presence of neurotoxins and endocrine disrupting substances in the environment.

  10. Roald Amundsen among the Magneticians: Polar Geophysics in the early 20th Century

    NASA Astrophysics Data System (ADS)

    Good, G. A.

    2013-12-01

    Roald Amundsen (1872-1928) is best known as a polar explorer, the first to lead a team to the South Pole in 1911. He did, however, have a serious interest in science, in particular, in geomagnetism. His expedition through the Northwest Passage above Canada in 1903 to 1906 and his Maud expedition through the Arctic ice in 1918 to 1925 included full complements of magnetic instrumentation. He and his magnetic researchers collaborated with the Carnegie Institution of Washington's Department of Terrestrial Magnetism and with the Prussian Geomagnetic Observatory in Potsdam for training, instruments, and research programs. Amundsen's expeditions provided magnetic and other geophysical data for important geographical regions, while gaining support for polar and geophysical research generally. His work is part of a broader 20th-century story that includes the International Polar Years and the International Geophysical Year.

  11. A possible 20th-century slowdown of southern ocean deep water formation

    PubMed

    Broecker; Sutherland; Peng

    1999-11-01

    Chlorofluorocarbon-11 inventories for the deep Southern Ocean appear to confirm physical oceanographic and geochemical studies in the Southern Ocean, which suggest that no more than 5 x 10(6) cubic meters per second of ventilated deep water is currently being produced. This result conflicts with conclusions based on the distributions of the carbon-14/carbon ratio and a quasi-conservative property, PO(4)(*), in the deep sea, which seem to require an average of about 15 x 10(6) cubic meters per second of Southern Ocean deep ventilation over about the past 800 years. A major reduction in Southern Ocean deep water production during the 20th century (from high rates during the Little Ice Age) may explain this apparent discordance. If this is true, a seesawing of deep water production between the northern Atlantic and Southern oceans may lie at the heart of the 1500-year ice-rafting cycle. PMID:10550046

  12. Changing Polygenic Penetrance on Phenotypes in the 20th Century Among Adults in the US Population

    PubMed Central

    Conley, Dalton; Laidley, Thomas M.; Boardman, Jason D.; Domingue, Benjamin W.

    2016-01-01

    This study evaluates changes in genetic penetrance—defined as the association between an additive polygenic score and its associated phenotype—across birth cohorts. Situating our analysis within recent historical trends in the U.S., we show that, while height and BMI show increasing genotypic penetrance over the course of 20th Century, education and heart disease show declining genotypic effects. Meanwhile, we find genotypic penetrance to be historically stable with respect to depression. Our findings help inform our understanding of how the genetic and environmental landscape of American society has changed over the past century, and have implications for research which models gene-environment (GxE) interactions, as well as polygenic score calculations in consortia studies that include multiple birth cohorts. PMID:27456657

  13. Cajal-Retzius cell physiology: just in time to bridge the 20th century.

    PubMed

    Mienville, J M

    1999-12-01

    Cajal-Retzius (CR) cells were discovered at the end of the 19th century but, surprisingly, the exploration of their physiological properties is only now beginning, as we near the end of the 20th century. A few papers addressing these properties have appeared recently, but incomplete data generally give the arguably misleading impression that CR cells are similar to other neocortical neurons, and therefore may perform analogous functions. It is one of the motives of this review to dispel such conceptions. Although CR cells display features of 'regular' neurons, including excitability and responsiveness to neurotransmitters, their function is probably limited to the primary implementation of cortical circuits. A strong indication in support of this idea is the fact that CR cells appear at the onset of neocorticogenesis and disappear at the end of neuronal migration. PMID:10600996

  14. CHANGES in SKIN TANNING ATTITUDES Fashion Articles and Advertisements in the Early 20th Century

    PubMed Central

    Martin, Jo M.; Ghaferi, Jessica M.; Cummins, Deborah L.; Mamelak, Adam J.; Schmults, Chrys D.; Parikh, Mona; Speyer, Lark-Aeryn; Chuang, Alice; Richardson, Hazel V.; Stein, David

    2009-01-01

    Historical reviews suggest that tanning first became fashionable in the 1920s or 1930s. To quantitatively and qualitatively examine changes in tanning attitudes portrayed in the popular women's press during the early 20th century, we reviewed summer issues of Vogue and Harper's Bazaar for the years 1920, 1927, 1928, and 1929. We examined these issues for articles and advertisements promoting skin tanning or skin bleaching and protection. We found that articles and advertisements promoting the fashionable aspects of tanned skin were more numerous in 1928 and 1929 than in 1927 and 1920, whereas those promoting pale skin (by bleaching or protection) were less numerous. These findings demonstrate a clear shift in attitudes toward tanned skin during this period. PMID:19846688

  15. Six calendar systems in the European history from 18^{th} to 20^{th} Century

    NASA Astrophysics Data System (ADS)

    Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijević, Milan S.

    The following calendar systems, introduced in Europe from 18^{th} to 20^{th} century, which were in use for a shorter or longer period by a larger or smaller community, were reviewed and discussed: The French Revolutionary Calendar, the Theosebic calendar invented by Theophilos Kairis, the Revolutionary Calendar of the Soviet Union (or 'Bolshevik calendar'), the Fascist calendar in Italy and the calendar of the Metaxas dictatorship in Greece before World War II. Also the unique of them, which is still in use, the New Rectified Julian calendar of the Orthodox Church, adopted according to proposition of Milutin Milanković on the Congress of Orthodox Churches in 1923 in Constantinople, is presented and discussed. At the end, difficulties to introduce a new calendar are discussed as well.

  16. Long run trends in the heights of European men, 19th-20th centuries.

    PubMed

    Hatton, Timothy J; Bray, Bernice E

    2010-12-01

    This paper presents 5-yearly data on the height of young adult men in 15 Western European countries for birth cohorts from the middle of the 19th to the end of the 20th century. The results indicate that from the 1870s to the 1970s average height increased by around 11 cm, or more than 1cm per decade. The main finding is that for the northern and middle European groups of countries the gains in height were most rapid in the period 1911-15 to 1951-55, a period that embraced two World Wars and the Great Depression but also witnessed advances in public health and hygiene. For the southern countries growth was fastest in the period 1951-55 to 1976-80. These findings suggest that advances in height were determined not only by income and living standards but also by a variety of other socioeconomic trends. PMID:20399715

  17. RTG's for space exploration at the end of the 20th century. [radioisotope thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Chmielewski, Art

    1989-01-01

    The use of radioisotope thermoelectric generators (RTGs) as energy conversion devices for spacecraft designed for weak-sunlight environments is discussed. The two upcoming missions Galileo and Ulysses will both use general-purpose heat source RTGs. Two other missions that are planned for the mid-nineties and will carry RTGs onboard are the comet rendezvous asteroid flyby and Cassini. Another mission that might become a program start in the last decade of the 20th century is Solarprobe, which is most likely to use modular RTGs. Several other missions that are in different planning stages that are in need of RTGs to meet their power requirements are the Mars rover sample return, planetary (Mars) penetrators, microspacecraft, and the Mars Egg. All of these missions are discssed, stressing their RTG requirements.

  18. Isotope Reanalysis for 20th century: Reproduction of isotopic time series in corals, tree-rings, and tropical ice cores

    NASA Astrophysics Data System (ADS)

    Yoshimura, K.

    2012-04-01

    In the present study, an isotope-incorporated GCM simulation for AD1871 to AD2008 nudged toward the so-called "20th Century Reanalysis (20CR)" atmospheric fields is conducted. Beforehand the long-term integration, a method to downscale ensemble mean fields is proposed, since 20CR is a product of 56-member ensemble Kalman filtering data assimilation. The method applies a correction to one of the ensemble members in such a way that the seasonal mean is equal to that of the ensemble mean, and then the corrected member is inputted into the isotope-incorporated GCM (i.e., IsoGSM) with the global spectral nudging technique. Use of the method clearly improves the skill than the cases of using only a single member and of using the ensemble means; the skill becomes equivalent to when 3-6 members are directly used. By comparing with GNIP precipitation isotope database, it is confirmed that the 20C Isotope Reanalysis's performance for latter half of the 20th century is just comparable to the other latest studies. For more comparisons for older periods, proxy records including corals, tree-rings, and tropical ice cores are used. First for corals: the 20C Isotope Reanalysis successfully reproduced the δ18O in surface sea water recorded in the corals at many sites covering large parts of global tropical oceans. The comparison suggests that coral records represent past hydrologic balance information where interannual variability in precipitation is large. Secondly for tree-rings: δ18O of cellulose extracted from the annual rings of the long-lived Bristlecone Pine from White Mountain in Southern California is well reproduced by 20C Isotope Reanalysis. Similar good performance is obtained for Cambodia, too. However, the mechanisms driving the isotopic variations are different over California and Cambodia; for California, Hadley cell's expansion and consequent meridional shift of the submerging dry zone and changes in water vapor source is the dominant control, but in Cambodia

  19. Abrupt and severe 20th Century changes in the fire regimes of southeastern Australia: Evidence from a 3000 year multi-proxy analysis

    NASA Astrophysics Data System (ADS)

    Baker, Patrick; Mooney, Scott; Allen, Kathryn; Willersdorf, Timothy

    2015-04-01

    Fire is the dominant natural disturbance in southeastern Australia. For millennia it has been the driving force shaping terrestrial ecosystems in the region -- simultaneously killing vegetation and initiating regeneration across whole landscapes. Fire regimes across the region are driven by several factors including climate, vegetation, and ignition sources. Humans have been a significant contributing factor to past and present fire regimes. Prior to European settlement in the late 1700s, Aboriginal Australians used frequent, low-intensity fires to manage vegetation across much of the landscape. European settlement led to the displacement of Aboriginal communities and a shift to active fire suppression and control. This changing approach to fire management is widely believed to have initiated a fundamental shift towards extreme, high-intensity fire events as fuel loads increased. In addition, during the 20th Century prolonged periods of warm, dry conditions have occurred with greater frequency and intensity. The relative importance of climate and fire management practices on contemporary fire regimes is vigorously debated in Australia and is directly relevant to land management policies and their implementation. To put the current fire regime into historical context, we used a multi-proxy approach combining palaeo-charcoal and tree-ring analyses to assess how fire regimes have changed over the last 3000 years in the Snowy Mountains region of southeastern Australia. We found almost no evidence of high-intensity fires in the 3000 years that preceded the 20th Century. However, in the mid-20th Century there is a sudden and dramatic increase in the presence of charcoal and the pulsed establishment of trees across the landscape, suggesting a recent shift from low-intensity fires with minimal charcoal signatures to moderate- to high-intensity fires with substantial charcoal inputs. Importantly, the tree-ring data demonstrate that most of these fires were not stand

  20. Impacts of 20th century aerosol emissions on the South Asian monsoon in the CMIP5 models

    NASA Astrophysics Data System (ADS)

    Turner, Andrew; Guo, Liang; Highwood, Eleanor

    2014-05-01

    Comparison of single-forcing varieties of 20th century historical experiments in a subset of models from the Fifth Coupled Model Intercomparison Project (CMIP5) reveals that South Asian summer monsoon rainfall increases towards the present day in GHG-only experiments with respect to pre-industrial levels, while it decreases in anthropogenic aerosol-only experiments. Comparison of these single-forcing runs with the all-forcings historical experiment suggests aerosol emissions have dominated South Asian monsoon rainfall trends in recent decades. By examining the 25 available all-forcings historical experiments, we show that models including aerosol indirect effects dominate this negative trend. Indeed, models including only the direct radiative effect of aerosol show an increase in monsoon rainfall, suggesting the dominance of increasing greenhouse gas emissions and planetary warming on monsoon rainfall in those models. The mechanism may be due to the indirect and direct effects acting in unison to suppress the monsoon, or to stronger local aerosol loading in the group of models containing indirect effects. The disparity between the two groups of models needs to be urgently investigated in the event that the suggested future decline in Asian anthropogenic aerosol emissions inherent to the representative concentration pathways (RCPs) used for future climate projection turns out to be optimistic.

  1. Quantifying the role of fire in the Earth system - Part 2: Impact on the net carbon balance of global terrestrial ecosystems for the 20th century

    SciTech Connect

    Li, Fang; Bond-Lamberty, Benjamin; Levis, Samuel

    2014-03-07

    Fire is the primary terrestrial ecosystem disturbance agent on a global scale. It affects carbon balance of global terrestrial ecosystems by emitting carbon to atmosphere directly and immediately from biomass burning (i.e., fire direct effect), and by changing net ecosystem productivity and land-use carbon loss in post-fire regions due to biomass burning and fire-induced vegetation mortality (i.e., fire indirect effect). Here, we provide the first quantitative assessment about the impact of fire on the net carbon balance of global terrestrial ecosystems for the 20th century, and investigate the roles of fire direct and indirect effects. This study is done by quantifying the difference between the 20th century fire-on and fire-off simulations with NCAR community land model CLM4.5 as the model platform. Results show that fire decreases net carbon gain of the global terrestrial ecosystems by 1.0 Pg C yr-1 average across the 20th century, as a results of fire direct effect (1.9 Pg C yr-1) partly offset by indirect effect (-0.9 Pg C yr-1). Fire generally decreases the average carbon gains of terrestrial ecosystems in post-fire regions, which are significant over tropical savannas and part of forests in North America and the east of Asia. The general decrease of carbon gains in post-fire regions is because fire direct and indirect effects have similar spatial patterns and the former (to decrease carbon gain) is generally stronger. Moreover, the effect of fire on net carbon balance significantly declines prior to ~1970 with trend of 8 Tg C yr-1 due to increasing fire indirect effect and increases afterward with trend of 18 Tg C yr-1 due to increasing fire direct effect.

  2. High GUD Incidence in the Early 20th Century Created a Particularly Permissive Time Window for the Origin and Initial Spread of Epidemic HIV Strains

    PubMed Central

    de Sousa, João Dinis; Müller, Viktor; Lemey, Philippe; Vandamme, Anne-Mieke

    2010-01-01

    The processes that permitted a few SIV strains to emerge epidemically as HIV groups remain elusive. Paradigmatic theories propose factors that may have facilitated adaptation to the human host (e.g., unsafe injections), none of which provide a coherent explanation for the timing, geographical origin, and scarcity of epidemic HIV strains. Our updated molecular clock analyses established relatively narrow time intervals (roughly 1880–1940) for major SIV transfers to humans. Factors that could favor HIV emergence in this time frame may have been genital ulcer disease (GUD), resulting in high HIV-1 transmissibility (4–43%), largely exceeding parenteral transmissibility; lack of male circumcision increasing male HIV infection risk; and gender-skewed city growth increasing sexual promiscuity. We surveyed colonial medical literature reporting incidences of GUD for the relevant regions, concentrating on cities, suffering less reporting biases than rural areas. Coinciding in time with the origin of the major HIV groups, colonial cities showed intense GUD outbreaks with incidences 1.5–2.5 orders of magnitude higher than in mid 20th century. We surveyed ethnographic literature, and concluded that male circumcision frequencies were lower in early 20th century than nowadays, with low rates correlating spatially with the emergence of HIV groups. We developed computer simulations to model the early spread of HIV-1 group M in Kinshasa before, during and after the estimated origin of the virus, using parameters derived from the colonial literature. These confirmed that the early 20th century was particularly permissive for the emergence of HIV by heterosexual transmission. The strongest potential facilitating factor was high GUD levels. Remarkably, the direct effects of city population size and circumcision frequency seemed relatively small. Our results suggest that intense GUD in promiscuous urban communities was the main factor driving HIV emergence. Low circumcision rates

  3. Quantifying the role of fire in the Earth system - Part 2: Impact on the net carbon balance of global terrestrial ecosystems for the 20th century

    NASA Astrophysics Data System (ADS)

    Li, F.; Bond-Lamberty, B.; Levis, S.

    2014-03-01

    Fire is the primary form of terrestrial ecosystem disturbance on a global scale. It affects the net carbon balance of terrestrial ecosystems by emitting carbon directly and immediately into the atmosphere from biomass burning (the fire direct effect), and by changing net ecosystem productivity and land-use carbon loss in post-fire regions due to biomass burning and fire-induced vegetation mortality (the fire indirect effect). Here, we provide the first quantitative assessment of the impact of fire on the net carbon balance of global terrestrial ecosystems during the 20th century, and investigate the roles of fire's direct and indirect effects. This is done by quantifying the difference between the 20th century fire-on and fire-off simulations with the NCAR Community Land Model CLM4.5 (prescribed vegetation cover and uncoupled from the atmospheric model) as a model platform. Results show that fire decreases the net carbon gain of global terrestrial ecosystems by 1.0 Pg C yr-1 averaged across the 20th century, as a result of the fire direct effect (1.9 Pg C yr-1) partly offset by the indirect effect (-0.9 Pg C yr-1). Post-fire regions generally experience decreased carbon gains, which is significant over tropical savannas and some North American and East Asian forests. This decrease is due to the direct effect usually exceeding the indirect effect, while they have similar spatial patterns and opposite sign. The effect of fire on the net carbon balance significantly declines until ∼1970 with a trend of 8 Tg C yr-1 due to an increasing indirect effect, and increases subsequently with a trend of 18 Tg C yr-1 due to an increasing direct effect. These results help constrain the global-scale dynamics of fire and the terrestrial carbon cycle.

  4. Fault Interaction and Stress Triggering of 20th Century Earthquakes in Mongolia

    NASA Astrophysics Data System (ADS)

    Pollitz, F.; Vergnolle, M.; Calais, E.

    2001-12-01

    A cluster of exceptionally large earthquakes in the interior of Asia occurred from 1905 to 1967: the 1905 M8.0 Tsetserleg and M8.4 Bolnai earthquakes, the 1931 M8.0 Fu Yun earthquake, the 1957 M8.1 Gobi-Altai earthquake, and the 1967 M7.1 Mogod earthquake. Each of the larger (M>8) earthquakes involved strike-slip faulting averaging more than 5 meters and rupture lengths of several hundred km. Available geologic data indicate that long-term slip rates are small, no more than 1-2 mm/yr, on each of the East-West trending faults which ruptured in the Bolnai and Gobi-Altai earthquakes, suggesting that earthquakes as large as those which occurred in the 20th century have repeat times of several 1000s of years. This raises the question as to how so many large earthquakes in this region could occur within a 62 year time interval, especially since distances of about 400 km separate the respective rupture areas. We propose that the occurrences of these and many smaller earthquakes are related and that their locations and style of faulting are controlled to a large extent by stress changes generated by the compounded static deformation of the preceding earthquakes and subsequent viscoelastic relaxation of the lower crust and upper mantle beneath Mongolia. We first estimate a spherically layered viscoelastic model constrained by the 1997-2001 GPS velocity field in Western Mongolia [Vergnolle et al., 2001]. A salient feature of the viscoelastic model is a low-viscosity ductile region occupying roughly the top 200 km of the mantle. Using the succession of 20th century earthquakes as sources of deformation, we then analyze the time-dependent change in Coulomb failure stress (Δ CFF). Stress evolution on the viscoelastic model consists of localized large stress steps at the times of occurrence of the source earthquakes followed by diffusion of stress pulses away from these sources. At remote interaction distances, static Δ CFF values are very small. However, modeled postseismic

  5. Reconstructing 20th Century Summer Precipitation on the South-Central Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Conroy, J. L.; Hudson, A. M.; Overpeck, J. T.; Cole, J. E.; Liu, K.; Wang, L.

    2011-12-01

    The Tibetan Plateau has experienced significant increases in temperature over the 20th century, but trends in precipitation are less clear, as station precipitation records are sparse and satellite observations only extend back to 1979. Here we use the sediment record from Ngamring Co, a closed-basin, freshwater lake in south-central Tibet, to assess summer precipitation over the last century. Ngamring Co is located in a watershed without glaciers, so recent changes in runoff and lake level are independent of the influence of glacial ice volume. The first principal component of the Ngamring Co grain size dataset is highly correlated with median grain size and covaries significantly with local July-August precipitation from the CPC Merged Analysis of Precipitation (CMAP). From 1979 to 2007, median grain size decreases with increasing July-August precipitation and increases with decreasing July-August precipitation. There is prominent multidecadal variability in the 20th century grain size record, including a gradual decline in median grain size from 1900 to 1930, a gradual increase in median grain size from 1930 to 1990, and a rapid decline in median grain size since 1990. Median grain size values from 2000-2007 are the lowest in the 107-year record, suggesting the most abundant monsoon precipitation in the last 107 years has occurred in the last decade. Satellite images of the lake also confirm an increase in lake area since the early 1990s, but also show the greatest lake area occurred in the 1970s. Thus, although summer precipitation and lake area do covary, precipitation does not seem to control grain size by influencing lake area. We presently hypothesize that increased July-August precipitation causes enhanced erosion of the fine-grained sediment (likely paleolake sediments and loess) that blankets the slopes surrounding the lake. The ensuing runoff and deposition of this sediment into the lake then results in a decline in median grain size within the lake

  6. Selected characteristics of meteorological elements and their trends since the mid-20th century in Slovakia

    NASA Astrophysics Data System (ADS)

    Fasko, Pavel; Švec, Marek; Šťastný, Pavel; Kajaba, Peter

    2014-05-01

    Analysis of some characteristics of air temperature, air humidity, precipitation and snow cover at selected meteorological stations located in different regions of Slovakia was performed for the period 1951 to 2012. Stations represent lowland regions (up to 300 meters), mid-altitude regions (300 to 800 meters) and high altitude mountain regions (above 1000 m). Series of highest annual maximum air temperature show obvious gradual increase from 80s of the 20th century on all selected stations and also the occurrence of new record values in the last years of the analyzed period 1951 -2012. In most stations the absolute maximum air temperature for 1951 - 2012 period was recorded during July 2007, whereas the highest annual maximum temperatures were recorded predominantly during the month of August in Slovakia. Values of annual maximum of mean daily temperature show evident upward trend and at some stations the highest mean daily temperature was recorded just in recent years (e.g. at station Sliač in 2012). Positive trends of the lowest annual minimum temperature at selected stations in the period 1951-2012 are not so significant and it is evident that the lowest annual minimum air temperature didn't drop as low as in the past, respectively they didn't reach record values as in the 50s or 80s of the 20-th century. Changes of minimum and maximum monthly precipitation totals during the year indicate that the number of cases with extremely low monthly total was increasing. Although frequency of occurrence of extremely high monthly precipitation totals was rather chaotic, in some recent years the observed values of monthly precipitation totals represented the absolutely highest monthly values for entire analyzed period 1951-2012. On the other hand, towards the end of this period, cases when minimum monthly precipitation totals were close to zero also became more common. Very significant is the trend in the lowest annual relative humidity in the 1951-2012 period

  7. Santorini Volcano's 20th Century Eruptions: A Combined Petrogenetical, Volcanological, Sociological and Environmental Study

    NASA Astrophysics Data System (ADS)

    Drymoni, Kyriaki; Magganas, Andreas; Pomonis, Panagiotis

    2014-05-01

    Santorini, the famous stratovolcano in the Aegean Sea, erupted three time periods during the 20th century (1925-1928, 1939-1941, 1950) and since then remains dormant. This study tried to combine and evaluate new and published volcanological, petrological, geochemical, environmental and sociological data of these three phases of Santorini's activity, which practically restricted to the caldera center on the Nea Kameni Islet. After field work on the formed dacite flows, pyroclastics and domes, representative rock samples and enclaves were collected and investigated for their texture, physical parameters, mineralogy and chemical composition by polarizing light microscope, scanning electron microscope (SEM-EDS), XRD, Raman spectroscopy and ICP-MS. The petrogenetic evaluation of the data obtained suggests slight but significant changes in the solid and aerial phases produced during the three explosion stages, which can be attributed to minor variations in the magmatic differentiation and magma chamber physicochemical conditions. These variations were also expressed by decrease of duration and intensity of the eruptions, as well as in their volume of ejecta and lava. Probably, the subsequent relatively long dormant period of the volcano is also related to this tension of decrease. The first compared results were collected from scientific literature, old photos as well as local and regional press and state documents from the different periods of volcanism, record the past hazard case scenarios and civil defense planning of the individual eruptions. As part of the disaster management a pilot survey, in which personal interviews with aged local islanders that were eye-witnesses of the events and elderly people or tourists that they indirectly experienced or have heard about them, was also conducted. This event-tracing, along with air pollution software models using volcanological data have shown the social impacts and the environmental consequences of the volcanic

  8. The distribution of an illustrated timeline wall chart and teacher's guide of 20th century physics

    SciTech Connect

    Schwartz, Brian

    2000-12-26

    The American Physical Society's part of its centennial celebration in March of 1999 decided to develop a timeline wall chart on the history of 20th century physics. This resulted in eleven consecutive posters, which when mounted side by side, create a 23-foot mural. The timeline exhibits and describes the millstones of physics in images and words. The timeline functions as a chronology, a work of art, a permanent open textbook, and a gigantic photo album covering a hundred years in the life of the community of physicists and the existence of the American Physical Society. Each of the eleven posters begins with a brief essay that places a major scientific achievement of the decade in its historical context. Large portraits of the essays' subjects include youthful photographs of Marie Curie, Albert Einstein, and Richard Feynman among others, to help put a face on science. Below the essays, a total of over 130 individual discoveries and inventions, explained in dated text boxes with accompanying images, form the backbone of the timeline. For ease of comprehension, this wealth of material is organized into five color-coded story lines the stretch horizontally across the hundred years of the 20th century. The five story lines are: Cosmic Scale, relate the story of astrophysics and cosmology; Human Scale, refers to the physics of the more familiar distances from the global to the microscopic; Atomic Scale, focuses on the submicroscopic world of atoms, nuclei and quarks; Living World, chronicles the interaction of physics with biology and medicine; Technology, traces the applications of physic to everyday living. Woven into the bottom border of the timeline are period images of significant works of art, architecture, and technological artifacts such as telephones, automobiles, aircraft, computers, and appliances. The last poster, covering the years since 1995, differs from the others. Its essay concerns the prospect for physics into the next century, and is illustrated

  9. Increasing cloud cover in the 20th century: review and new findings in Spain

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, A.; Calbó, J.; Wild, M.

    2012-07-01

    Visual observations of clouds have been performed since the establishment of meteorological observatories during the early instrumental period, and have become more systematic and reliable after the mid-19th century due to the establishment of the first national weather services. During the last decades a large number of studies have documented the trends of the total cloud cover (TCC) and cloudy types; most of these studies focus on the trends since the second half of the 20th century. Due to the lower reliability of former observations, and the fact that most of this data is not accessible in digital format, there is a lack of studies focusing on the trends of cloudiness since the mid-19th century. In the first part, this work attempts to review previous studies analyzing TCC changes with information covering at least the first half of the 20th century. Then, the study analyses a database of cloudiness observations in Southern Europe (Spain) since the second half of the 19th century. Specifically, monthly TCC series were reconstructed since 1866 by means of a so-called parameter of cloudiness, calculated from the number of cloudless and overcast days. These estimated TCC series show a high interannual and decadal correlation with the observed TCC series originally measured in oktas. After assessing the temporal homogeneity of the estimated TCC series, the mean annual and seasonal series for the whole of Spain and several subregions were calculated. The mean annual TCC shows a general tendency to increase from the beginning of the series until the 1960s; at this point, the trend becomes negative. The linear trend for the annual mean series, estimated over the 1866-2010 period, is a highly remarkable (and statistically significant) increase of +0.44% per decade, which implies an overall increase of more than +6% during the analyzed period. These results are in line with the majority of the trends observed in many areas of the world in previous studies, especially

  10. Impacts of the EA and SCA patterns on the 20th century NAO-winter precipitation relationship in Europe

    NASA Astrophysics Data System (ADS)

    Comas-Bru, Laia; McDermott, Frank

    2013-04-01

    Much of the 20th century multi-decadal variability in the NAO-winter precipitation relationship over the N. Atlantic / European sector can be ascribed to the combined effects of the North Atlantic Oscillation (NAO) and either the East Atlantic pattern (EA) or the Scandinavian pattern (SCA). The NAO, EA and SCA indices employed here are defined as the three leading vectors of the cross-correlation matrix calculated from monthly sea-level pressure anomalies for 138 complete winters from the 20CRv2 dataset (Compo et al., 2011). Winter precipitation data over Europe for the entire 20th century is derived from the high resolution CRU-TS3.1 climate dataset (Mitchell and Jones, 2005). Here we document for the first time, that different NAO/EA and NAO/SCA combinations systematically influence winter precipitation conditions in Europe as a consequence of NAO dipole migrations. We find that the zero-correlated line of the NAO-winter precipitation relationship migrates southwards when the EA is in the opposite phase to the NAO. This can be related to a south-westwards migration of the NAO dipole under these conditions, as shown by teleconnectivity maps. Similarly, a clockwise movement of the NAO-winter climate correlated areas occurs when the phase of the SCA is opposite to that of the NAO, reflecting a clockwise movement of the NAO dipole under these conditions. An important implication of these migrations is that they influence the spatial and temporal stationarity of climate-NAO relationships. As a result, the link between winter precipitation patterns and the NAO is not straightforward in some regions such as the southern UK, Ireland and France. For instance, much of the inter-annual variability in the N-S winter precipitation gradient in the UK, originally attributed to inter-annual and inter-decadal variability of the NAO, reflects the migration of the NAO dipole, linked to linear combinations of the NAO and the EA. Our results indicate that when the N-S winter

  11. Reducing Uncertainties in Future Climate Projections by Quantifying Human COntributions to 20th Century Climate Change

    SciTech Connect

    Gabriele Hegerl and IDAG members

    2011-07-31

    This report focuses on the period to 2010 including, after which the new round of the International Detection and Attribution group, led by Claudia Tebaldi, started. In 2011, some final work on report has been done, and outstanding tasks completed. However, most participants are now working on the new grant and hence the citations and work reported is focusing largely on the regular grant period.

  12. Dominating north american forest pathology issues of the 20th century.

    PubMed

    Macdonald, William L

    2003-08-01

    ABSTRACT The profession of forest pathology evolved in the early decades of the 20th century from a science describing microorganisms that infect trees to a discipline that was required to deal with numerous disease outbreaks. The foundations of the science were carried from Europe to the "New World" and initially dealt with decay and the resource losses it caused. The profession was forced to shift direction quickly because it was called upon to address major diseases caused by the introduction of pathogens from other continents; notably organisms inciting chestnut blight, Dutch elm disease, and white pine blister rust. Changes in natural ecosystems that resulted from a legacy of poor forest practice, land abuse, and an increase in plantation monocultures gave rise to other disease problems when host-pathogen balances in natural ecosystems were disturbed. Further, the need for large numbers of tree seedlings resulted in numerous nursery disease problems. Although many of the principles of general plant pathology had application to the study of forest diseases, the long-term nature of forests requires varied approaches to their study and management. Today, the science continues to evolve as the complexities of forest ecosystems unfold. PMID:18943872

  13. Age-specific measles mortality during the late 19th-early 20th centuries.

    PubMed

    Shanks, G D; Waller, M; Briem, H; Gottfredsson, M

    2015-12-01

    Measles mortality fell prior to the introduction of vaccines or antibiotics. By examining historical mortality reports we sought to determine how much measles mortality was due to epidemiological factors such as isolation from major population centres or increased age at time of infection. Age-specific records were available from Aberdeen; Scotland; New Zealand and the states of Australia at the end of the 19th and beginning of the 20th centuries. Despite the relative isolation of Australia, measles mortality was concentrated in very young children similar to Aberdeen. In the more isolated states of Tasmania, Western Australia and Queensland adults made up 14-15% of measles deaths as opposed to 8-9% in Victoria, South Australia and New South Wales. Mortality in Iceland and Faroe Islands during the 1846 measles epidemic was used as an example of islands isolated from respiratory pathogens. The transition from crisis mortality across all ages to deaths concentrated in young children occurred prior to the earliest age-specific mortality data collected. Factors in addition to adult age of infection and epidemiological isolation such as nutritional status and viral virulence may have contributed to measles mortality outcomes a century ago. PMID:25865777

  14. High-resolution record of pyrogenic polycyclic aromatic hydrocarbon deposition during the 20th century.

    PubMed

    Lima, Ana Lúcia C; Eglinton, Timothy I; Reddy, Christopher M

    2003-01-01

    A high-resolution record of polycyclic aromatic hydrocarbon (PAH) deposition in Rhode Island over the past approximately 180 years was constructed using a sediment core from the anoxic Pettaquamscutt River basin. The record showed significantly more structure than has hitherto been reported and revealed four distinct maxima in PAH flux. The characteristic increase in PAH flux at the turn of the 20th century was captured in detail, leading to an initial maximum prior to the Great Depression. The overall peak in PAH flux in the 1950s was followed by a maximum that immediately preceded the 1973 Organization of Petroleum Exporting Countries (OPEC) oil embargo. During the most recent portion of the record, an abrupt increase in PAH flux between 1996 and 1999 has been found to follow a period of near constant fluxes. Because source-diagnostic ratios indicate that petrogenic inputs are minor throughout the record, these trends are interpreted in terms of past variations in the magnitude and type of combustion processes. For the most recent PAH maximum, energy consumption data suggest that diesel fuel combustion, and hence traffic of heavier vehicles, is the most probable cause for the increase in PAH flux. Systematic variations in the relative abundance of individual PAHs in conjunction with the above changes in flux are interpreted in relation to the evolution of combustion processes. Coronene, retene, and perylene are notable exceptions, exhibiting unique down-core profiles. PMID:12542290

  15. The 20th century Danish facial cleft population--epidemiological and genetic-epidemiological studies.

    PubMed

    Christensen, K

    1999-03-01

    Since Dr. Fogh-Andersen's legendary 1942 thesis, the Danish facial cleft population has been one of the most extensively studied in terms of epidemiology and genetic-epidemiology. The etiology of cleft lip and/or palate (CLP) is still largely an enigma, and different results concerning environmental and genetic risk factors are obtained in different countries and regions. This may be due to etiological heterogeneity between settings. Therefore, an in-depth studied area with an ethnically homogeneous population, such as Denmark, has provided one of the best opportunities for progress in CLP etiological research. The present review summarizes epidemiological and genetic-epidemiological studies conducted in the 20th century Danish facial cleft population. Furthermore, analyses of sex differences, time trends and seasonality for more than 7000 CLP cases born in Denmark in the period 1936 to 1987 are presented. The review also points toward the excellent opportunities for continued etiological CLP research in Denmark in the 21st century using already established resources and an on-going prospective cohort study of 100,000 pregnant women. PMID:10213053

  16. Dental health of the late 19th and early 20th century Khoesan.

    PubMed

    Botha, D; Steyn, M

    2015-06-01

    This paper presents the results of the dental analysis performed on a Khoesan skeletal sample representing the late 19th and early 20th century Cape Colony in southern Africa. Skeletal material from two European collections (Vienna and Paris) was selected to compile a total sample of 116 specimens. Dental pathology frequencies were calculated for caries (28.4%), antemortem tooth loss (37.9%), periapical abscesses (29.3%), periodontal disease (26.7%), calculus (44.0%) and impacted canines (4.3%). Attrition scores indicated that the group under study had an average rate of attrition compared to other southern African populations. Frequency and intensity data were compared to several other samples from both the pre-contact and contact phases by means of chi-squared analysis. The outcome of the study suggested that the group under study was most likely in a state of transition between a diet and lifestyle of hunting-and-gathering and agriculture. Results were also consistent with those of groups from a low socio-economic status. PMID:25882044

  17. Quantifying 20th century deposition in complex estuarine environment: An example from the Hudson River

    NASA Astrophysics Data System (ADS)

    Nitsche, F. O.; Kenna, T. C.; Haberman, M.

    2010-09-01

    Sediment processes in estuaries are controlled by the interaction of factors that include tides, fresh water inputs, bed morphology, sediment supply, and hydrodynamics. The interaction of these factors strongly influences the pattern of sediment deposition. The ability to quantify sediment deposition on a regional scale will improve the understanding of the underlying processes, and provide valuable information for managing estuarine systems. This paper describes our approach for obtaining the deposition pattern and quantifying the amount of 20th century impacted sediments in the Haverstraw Bay section of the Hudson River Estuary. Through the combination of high-resolution seismic data and rapidly acquired geochemical information from numerous sediment cores, we estimate that our study site experiences an average sediment accumulation rate of ˜3 mm/y and that ˜75,000 t/y or ˜10% of the annual total sediment input measured at the Poughkeepsie, NY gauging station (USGS) is stored in this reach of the Hudson River on ˜100 y timescales. A detailed analysis of the depositional pattern indicates that the accumulation rate varies considerably throughout the study area ranging from non-depositional to >8 mm/y. Our data also clearly indicate that the dredged channel in Haverstraw Bay is currently the main focus of deposition in this area.

  18. Molecular Evolution of Zika Virus during Its Emergence in the 20th Century

    PubMed Central

    Iamarino, Atila; Faye, Ousmane; de Oliveira, Juliana Velasco C.; Diallo, Mawlouth; Zanotto, Paolo M. A.; Sall, Amadou Alpha

    2014-01-01

    Zika virus (ZIKV) is a mosquito-borne flavivirus first isolated in Uganda in 1947. Although entomological and virologic surveillance have reported ZIKV enzootic activity in diverse countries of Africa and Asia, few human cases were reported until 2007, when a Zika fever epidemic took place in Micronesia. In the context of West Africa, the WHO Collaborating Centre for Arboviruses and Hemorrhagic Fever at Institut Pasteur of Dakar (http://www.pasteur.fr/recherche/banques/CRORA/) reports the periodic circulation of ZIKV since 1968. Despite several reports on ZIKV, the genetic relationships among viral strains from West Africa remain poorly understood. To evaluate the viral spread and its molecular epidemiology, we investigated 37 ZIKV isolates collected from 1968 to 2002 in six localities in Senegal and Côte d'Ivoire. In addition, we included strains from six other countries. Our results suggested that these two countries in West Africa experienced at least two independent introductions of ZIKV during the 20th century, and that apparently these viral lineages were not restricted by mosquito vector species. Moreover, we present evidence that ZIKV has possibly undergone recombination in nature and that a loss of the N154 glycosylation site in the envelope protein was a possible adaptive response to the Aedes dalzieli vector. PMID:24421913

  19. The mid 19th and early 20th Century Pull of a Nearby Eclipse Shadow Path

    NASA Astrophysics Data System (ADS)

    Bonifácio, Vitor

    2012-09-01

    The unique observing conditions allowed by total solar eclipses made them a highly desirable target of 19th and early 20th century astronomical expeditions, particularly after 1842. Due to the narrowness of the lunar shadow at the Earth's surface this usually implied traveling to faraway locations with all the subsequent inconveniences, in particular, high costs and complex logistics. A situation that improved as travel became faster, cheaper and more reliable. The possibility to observe an eclipse in one's own country implied no customs, no language barriers, usually shorter travelling distances and the likely support of local and central authorities. The eclipse proximity also provided a strong argument to pressure the government to support the eclipse observation. Sometimes the scientific elite would use such high profile events to rhetorically promote broader goals. In this paper we will analyse the motivation, goals, negotiating strategies and outcomes of the Portuguese eclipse expeditions made between 1860 and 1914. We will focus, in particular, on the observation of the solar eclipses of 22 December 1870 and 17 April 1912. The former allowed the start-up of astrophysical studies in the country while the movie obtained at the latter led Francisco da Costa Lobo to unexpectedly propose a polar flattening of the Moon.

  20. Newly identified historical tornadoes in the Czech Republic from 16th to the 20th centuries

    NASA Astrophysics Data System (ADS)

    Lacinová, Martina; Munzar, Jan; Franc, Marek

    2007-02-01

    Tornadoes have occurred in the territory of the Czech Republic throughout history. Although their frequency and intensity are not as high as in the USA, they can cause severe damage as well. That is why a systematic effort to document individual occurrences of this dangerous meteorological phenomenon as far as possible back into the past began in the 1990s. The aim of this investigation is to extend the first European catalogue of tornadoes originally published by Wegener [Wegener A., 1917. Wind-und Wasserhosen in Europe], by the addition of these cases from the Czech Republic. This paper adds further to Setvák, Šálek and Munzar [ Setvák M., Šálek M., Munzar J., 2003. Tornadoes within the Czech Republic—from medieval chronicles to the internet society. Atmos. Res. 67-68, 589-605], who reported the earliest documented tornado in the land of the Czech Republic which occurred in AD 1119 in Prague. In so doing, it presents recently discovered tornado cases from the 16th to the early 20th centuries, found in a variety of historical sources since the last ECSS conference held in Prague in 2002. In particular we will focus on the case from Jablonec nad Nisou (northern Bohemia) in 1925, which was probably the first case in the Czech Republic with accompanying photographic documentation of damage caused by a tornado.

  1. Molecular evolution of Zika virus during its emergence in the 20(th) century.

    PubMed

    Faye, Oumar; Freire, Caio C M; Iamarino, Atila; Faye, Ousmane; de Oliveira, Juliana Velasco C; Diallo, Mawlouth; Zanotto, Paolo M A; Sall, Amadou Alpha

    2014-01-01

    Zika virus (ZIKV) is a mosquito-borne flavivirus first isolated in Uganda in 1947. Although entomological and virologic surveillance have reported ZIKV enzootic activity in diverse countries of Africa and Asia, few human cases were reported until 2007, when a Zika fever epidemic took place in Micronesia. In the context of West Africa, the WHO Collaborating Centre for Arboviruses and Hemorrhagic Fever at Institut Pasteur of Dakar (http://www.pasteur.fr/recherche/banques/CRORA/) reports the periodic circulation of ZIKV since 1968. Despite several reports on ZIKV, the genetic relationships among viral strains from West Africa remain poorly understood. To evaluate the viral spread and its molecular epidemiology, we investigated 37 ZIKV isolates collected from 1968 to 2002 in six localities in Senegal and Côte d'Ivoire. In addition, we included strains from six other countries. Our results suggested that these two countries in West Africa experienced at least two independent introductions of ZIKV during the 20(th) century, and that apparently these viral lineages were not restricted by mosquito vector species. Moreover, we present evidence that ZIKV has possibly undergone recombination in nature and that a loss of the N154 glycosylation site in the envelope protein was a possible adaptive response to the Aedes dalzieli vector. PMID:24421913

  2. Stationarity analysis of historical flood series in France and Spain (14th-20th centuries)

    NASA Astrophysics Data System (ADS)

    Barriendos, M.; Coeur, D.; Lang, M.; Llasat, M. C.; Naulet, R.; Lemaitre, F.; Barrera, A.

    Interdisciplinary frameworks for studying natural hazards and their temporal trends have an important potential in data generation for risk assessment, land use planning, and therefore the sustainable management of resources. This paper focuses on the adjustments required because of the wide variety of scientific fields involved in the reconstruction and characterisation of flood events for the past 1000 years. The aim of this paper is to describe various methodological aspects of the study of flood events in their historical dimension, including the critical evaluation of old documentary and instrumental sources, flood-event classification and hydraulic modelling, and homogeneity and quality control tests. Standardized criteria for flood classification have been defined and applied to the Isère and Drac floods in France, from 1600 to 1950, and to the Ter, the Llobregat and the Segre floods, in Spain, from 1300 to 1980. The analysis on the Drac and Isère data series from 1600 to the present day showed that extraordinary and catastrophic floods were not distributed uniformly in time. However, the largest floods (general catastrophic floods) were homogeneously distributed in time within the period 1600-1900. No major flood occurred during the 20th century in these rivers. From 1300 to the present day, no homogeneous behaviour was observed for extraordinary floods in the Spanish rivers. The largest floods were uniformly distributed in time within the period 1300-1900, for the Segre and Ter rivers.

  3. North Atlantic wave height trends as reconstructed from the 20th century reanalysis

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolan L.; Feng, Yang; Swail, V. R.

    2012-09-01

    This study reports on the 1871-2010 trends in significant wave heights (Hs) in the North Atlantic, as statistically reconstructed from the 20th century reanalysis (20CR) ensemble of mean sea level pressure (SLP) fields. The 20CR SLP data set for the North Atlantic has been reported to be homogeneous since 1871, although it has discontinuities before 1949 in other regions. A multivariate regression model with lagged dependent variable is used to represent the SLP-Hs relationship. It is calibrated and validated using the ERA-Interim reanalysis of Hs and SLP for the period 1981-2010.Trends in the reconstructed annual mean and maximum Hs are found to be consistent with those derived from two dynamical wave reanalysis data sets (MSC50 and ERA40), which indicates robustness of the trend estimates. The trend patterns of extreme Hs generally feature increases in the northeast North Atlantic with decreases in the mid-latitudes; but there are seasonal variations. The main features of the patterns of trends over the last half century or so are also seen in the last 140-yr period (1871-2010). However, the trend magnitudes are much greater in the last half century than in the 140 years.

  4. [Pollock, Warhol, Basquiat, Haring 20th century American painters from a psychological perspective].

    PubMed

    Petôvári, Csaba

    2010-01-01

    Pollock, Warhol, Basquiat and Haring made an international reputation for themselves with their art foremost of the American artists of the 20th century, and became pop cultural icons for the man in the street and for the media as well. Accordingly to the habits of the consumer society their art and even themselves become product and consumer's goods. Their not mistaken, individual style - which also became their trademark - makes that possible. The connection between the four artists is that each of them had a dependent personality, their fine art activity was arguable in their period, and after all themselves and his artworks get into the increased attention of the media. These four artists embody the brand-new artist type, who steps into a star status. Besides the artworks the artist also get into the focus of interest. Through psychological aspect their artworks tell a lot about their way of life, their personality, and the social estate around them. Four of them were catalysts, they set new art trends. The influence of Basquiat and Haring stretched over to the 21st century, and keeps going in the graffiti street-art which gets into the "high art" at last, and captivates the art galleries and critics as well. PMID:20938058

  5. René leriche and the development of 20(th) century surgery.

    PubMed

    Ioncioaia, Bogdan; Bud, Ioan Teodor; Muresan, Mircea

    2016-01-01

    René Leriche (1879-1955) was a 20(th) century French surgeon generally known in medicine for the syndrome that carries his name, namely the Leriche syndrome in the aorto-iliac occlusive disease. This paper is published to mark the commemoration of 60 year since Leriche's death. Although Dr. Leriche's legacy resides in the domain of vascular medicine, his research enclosed bone pathology and surgical management of pain. Having his surgical training done under professors Mathieu Jaboulay and Antonin Poncet, his friendship and association with Alexis Carrel and William Halsted have contributed to René Leriche's development as a surgeon, researcher and thinker. Following the footsteps of his mentors, he produced outstanding clinical and academic work which had earned him a good reputation among his students and colleagues. Surgeons such as Jean Kunlin, Jao Cid dos Santos, Michael DeBakey, René Fontaine and others came to study and learn from him. These future generations of surgeons would themselves bring much contribution to the understanding and treatment of vascular diseases and medicine in general. René Leriche pioneered medicine with his research and ideas. His assiduous work of teaching, research and clinical practice made his influence last to our present. PMID:27004042

  6. René leriche and the development of 20th century surgery

    PubMed Central

    IONCIOAIA, BOGDAN; BUD, IOAN TEODOR; MURESAN, MIRCEA

    2016-01-01

    René Leriche (1879–1955) was a 20th century French surgeon generally known in medicine for the syndrome that carries his name, namely the Leriche syndrome in the aorto-iliac occlusive disease. This paper is published to mark the commemoration of 60 year since Leriche’s death. Although Dr. Leriche’s legacy resides in the domain of vascular medicine, his research enclosed bone pathology and surgical management of pain. Having his surgical training done under professors Mathieu Jaboulay and Antonin Poncet, his friendship and association with Alexis Carrel and William Halsted have contributed to René Leriche’s development as a surgeon, researcher and thinker. Following the footsteps of his mentors, he produced outstanding clinical and academic work which had earned him a good reputation among his students and colleagues. Surgeons such as Jean Kunlin, Jao Cid dos Santos, Michael DeBakey, René Fontaine and others came to study and learn from him. These future generations of surgeons would themselves bring much contribution to the understanding and treatment of vascular diseases and medicine in general. René Leriche pioneered medicine with his research and ideas. His assiduous work of teaching, research and clinical practice made his influence last to our present. PMID:27004042

  7. Reconciling past changes in Earth's rotation with 20th century global sea-level rise: Resolving Munk's enigma.

    PubMed

    Mitrovica, Jerry X; Hay, Carling C; Morrow, Eric; Kopp, Robert E; Dumberry, Mathieu; Stanley, Sabine

    2015-12-01

    In 2002, Munk defined an important enigma of 20th century global mean sea-level (GMSL) rise that has yet to be resolved. First, he listed three canonical observations related to Earth's rotation [(i) the slowing of Earth's rotation rate over the last three millennia inferred from ancient eclipse observations, and changes in the (ii) amplitude and (iii) orientation of Earth's rotation vector over the last century estimated from geodetic and astronomic measurements] and argued that they could all be fit by a model of ongoing glacial isostatic adjustment (GIA) associated with the last ice age. Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~1.5 to 2.0 mm/year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA-corrected observations of Earth's rotation. We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations. This resolution adds confidence to recent estimates of individual contributions to 20th century sea-level change and to projections of GMSL rise to the end of the 21st century based on them. PMID:26824058

  8. DIGEST MATERIALS FOR IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY. VOLUME 4, 20TH CENTURY.

    ERIC Educational Resources Information Center

    MOORE, JUNE

    PREPARED AS PART OF "PROJECT IMPROVING AND EXTENDING THE JUNIOR HIGH SCHOOL ORCHESTRA REPERTORY," THIS VOLUME CONTAINS CURRICULAR MATERIALS REPRESENTING THE 20TH CENTURY PERIOD. A MUSICAL HISTORY OF THE PERIOD IS GIVEN, AS WELL AS HISTORIES OF THE COMPOSERS AND THEIR INDIVIDUAL COMPOSITIONS. THE MATERIALS ARE PREPARED FOR 3 DEGREES OF TECHNICAL…

  9. Representations of Technology in the "Technical Stories" for Children of Otto Witt, Early 20th Century Swedish Technology Educator

    ERIC Educational Resources Information Center

    Axell, Cecilia; Hallström, Jonas

    2013-01-01

    Children's fiction in school libraries have played and still play a role in mediating representations of technology and attitudes towards technology to schoolchildren. In early 20th century Sweden, elementary education, including textbooks and literature that were used in teaching, accounted for the main mediation of technological knowledge…

  10. Images of Commitment: 20th Century Women Artists. A Fine Art Print Program: Junior/Senior High.

    ERIC Educational Resources Information Center

    Kordich, Diane D.

    This teacher's resource guide is designed to accompany resource packets that include fine art reproductions. The resource introduces students to the accomplishments and contributions of eight 20th century women artists: Isabel Bishop; Jenny Holzer; Kathe Kollwitz; Maya Ying Lin; Mary Ellen Mark; Maria Martinez; Alice Neel; and Faith Ringgold. This…

  11. Socialization into a Civilization: The Dewey-Kaplan Synthesis in American Jewish Schooling in the Early 20th Century

    ERIC Educational Resources Information Center

    Jacobs, Benjamin M.

    2009-01-01

    This historical study focuses on how John Dewey's theory of education as socialization and Mordecai Kaplan's theory of Judaism as a civilization together served as an ideological base and pedagogical framework for the creation of "progressive," "reconstructed" American Jewish school programs in the early 20th century (1910s-1930s). In the main,…

  12. Beyond the Standard Measures: Physical Education's Impact on the Dialogue about Obesity in the 20th Century

    ERIC Educational Resources Information Center

    Wrynn, Alison M.

    2011-01-01

    As numerous Homans' lecturers have attested, Amy Morris Homans was a significant and visionary leader who set the foundation for women's physical education for the first half of the 20th century. Her reign at the Boston Normal School for Gymnastics (BNSG) was ironclad, and through the BNSG she controlled her student's lives, including their…

  13. An Epistemological Approach to French Syllabi on Human Origins during the 19th and 20th Centuries

    ERIC Educational Resources Information Center

    Quessada, Marie-Pierre; Clement, Pierre

    2007-01-01

    This study focuses on how human origins were taught in the French Natural Sciences syllabuses of the 19th and 20th centuries. We evaluate the interval between the publication of scientific concepts and their emergence in syllabuses, i.e., didactic transposition delay (DTD), to determine how long it took for scientific findings pertaining to our…

  14. Some Thoughts on the Race Against Time and Inherent Vice: Preservation Program Development in Late 20th Century America.

    ERIC Educational Resources Information Center

    Roosa, Mark

    This paper traces the roots of the current library preservation movement and its evolution during the second half of the 20th century. It also looks at some of the contemporary shifts in thinking about preservation and changes in practice that are being explored by libraries. Finally the paper draws some conclusions as to the scope of programs in…

  15. Lens and cataract research of the 20th century: a review of results, errors and misunderstandings.

    PubMed

    Hockwin, Otto; Kojima, Masami; Müller-Breitenkamp, Ursula; Wegener, Alfred

    2002-01-01

    Lens and cataract research from a clinical, biophysical, biological and mainly biochemical point of view has a long tradition. Already since the beginning of the 20th century research relating to the chemical composition and metabolism of the lens was conducted. With these analyses an attempt was made to understand the existence and maintenance of lens transparency and the mechanisms leading to lens opacities. Around the middle of the century the stationary analyses measuring the content of certain substances in the lens were more and more replaced by the search for dynamic metabolic processes responsible for lens growth, maintenance of transparency and possibly active participation in lens function (such as accommodation). Also the disturbances as a result of ageing or the formation of lens opacities have been investigated and resulted partially in the elucidation of reaction chains, leading from a trigger to the formation of a cataract. Lens biochemistry is no longer a closed book to us, but there are still many question marks. Why were we not able to solve more problems around lens and cataract? The research effort with a remarkable financial input and a great number of scientists worldwide during the second half of the century does not correspond to the results obtained. There must be something wrong with our strategy, our interpretation of the results or even both. We would like to stress some points which might be regarded as errors or misunderstandings in the lens research community, thus preventing a better outcome of the enormous investment of work and money. A great disadvantage is the missing cooperation between clinicians and epidemiologists on one hand and basic lens researchers on the other. Especially the ignorance of basic researchers regarding the clinical problems of the lens and of cataracts might be to blame for several 'errors and misunderstandings'. It is not even so long ago since the slitlamp microscope examination of animals belonged to the

  16. Conceptual Revolution of the 20th Century Leading to One Grand Unified Concept -- The Quantum Vacuum

    NASA Astrophysics Data System (ADS)

    Sreekantan, B. V.

    2014-07-01

    Concepts and the relations between concepts are the basis for all our scientific understanding and explanation of the wide variety of constituents and phenomena in nature. Some of the fundamental concepts like space, time, matter, radiation, causality, etc. had remained unchanged for almost four hundred years from the time of the dawn of science. However all these underwent a drastic transformation in the 20th century because of two reasons. One, in the light of certain experimental findings two radical theories namely theory of relativity and theory of quantum mechanics replaced the classical theory that had dominated since Newton's time. Secondly, the science-technology spiral resulted in the discovery of very many new features of the universe both on the micro scale and on the mega scale. There was an exponential increase in our knowledge. These new facts could not be fitted into the old concepts. Apart from drastic revision, many new concepts had to be brought in. Despite all this, one very encouraging trend has been to discern a holistic synthesis and unification of the different concepts -- an endeavor that has been helped by experiments over a wide scale of energy and distances and most importantly from theoretical insights triggered by mathematical underpinnings. These developments in physics and astrophysics are pointing to one grand concept, namely, the "quantum vacuum" endowed with certain special properties, as the substratum from which all the constituents of the universe as well as the processes of the universe emerge, including the creation of the universe itself. This is the view, at least of some of the scientists. In this brief article the essence of these approaches toward unification is highlighted. Maybe life sciences can take a clue from these developments in physical sciences.

  17. Ochres and earths: Matrix and chromophores characterization of 19th and 20th century artist materials

    NASA Astrophysics Data System (ADS)

    Montagner, Cristina; Sanches, Diogo; Pedroso, Joana; Melo, Maria João; Vilarigues, Márcia

    2013-02-01

    The present paper describes the main results obtained from the characterization of a wide range of natural and synthetic ochre samples used in Portugal from the 19th to the 20th century, including powder and oil painting samples. The powder ochre samples came from several commercial distributors and from the collection of Joaquim Rodrigo (1912-1997), a leading Portuguese artist, particularly active during the sixties and seventies. The micro-samples of oil painting tubes came from the Museu Nacional de Arte Contemporânea-Museu do Chiado (National Museum of Contemporary Art-Chiado Museum) in Lisbon and were used by Columbano Bordalo Pinheiro (1857-1929), one of the most prominent naturalist Portuguese painters. These tubes were produced by the main 19th century colourmen: Winsor & Newton, Morin et Janet, Maison Merlin, and Lefranc. The samples have been studied using μ-Fourier Transform Infrared Spectroscopy (μ-FTIR), Raman microscopy, μ-Energy Dispersive X-ray fluorescence (μ-EDXRF), and X-ray diffraction (XRD). The analyzed ochres were found to be a mixture of several components: iron oxides and hydroxides in matrixes with kaolinite, gypsum and chalk. The results obtained allowed to identify and characterize the ochres according to their matrix and chromophores. The main chromophores where identified by Raman microscopy as being hematite, goethite and magnetite. The infrared analysis of the ochre samples allowed to divide them into groups, according to the composition of the matrix. It was possible to separate ochres containing kaolinite matrix and/or sulfate matrix from ochres where only iron oxides and/or hydroxides were detected. μ-EDXRF and Raman were the best techniques to identify umber, since the presence of elements such as manganese is characteristic of these pigments. μ-EDXRF also revealed the presence of significant amounts of arsenic in all Sienna tube paints.

  18. The 20th-century development and expansion of Louisiana shelf hypoxia, Gulf of Mexico

    USGS Publications Warehouse

    Osterman, L.E.; Poore, R.Z.; Swarzenski, P.W.; Senn, D.B.; DiMarco, S.F.

    2009-01-01

    Since systematic measurements of Louisiana continental-shelf waters were initiated in 1985, hypoxia (oxygen content <2 mg L-1) has increased considerably in an area termed the dead zone. Monitoring and modeling studies have concluded that the expansion of the Louisiana shelf dead zone is related to increased anthropogenically derived nutrient delivery from the Mississippi River drainage basin, physical and hydrographical changes of the Louisiana Shelf, and possibly coastal erosion of wetlands in southern Louisiana. In order to track the development and expansion of seasonal low-oxygen conditions on the Louisiana shelf prior to 1985, we used a specific low-oxygen foraminiferal faunal proxy, the PEB index, which has been shown statistically to represent the modern Louisiana hypoxia zone. We constructed a network of 13 PEB records with excess 210Pb-derived chronologies to establish the development of low-oxygen and hypoxic conditions over a large portion of the modern dead zone for the last 100 years. The PEB index record indicates that areas of low-oxygen bottom water began to appear in the early 1910s in isolated hotspots near the Mississippi Delta and rapidly expanded across the entire Louisiana shelf beginning in the 1950s. Since ???1950, the percentage of PEB species has steadily increased over a large portion of the modern dead zone. By 1960, subsurface low-oxygen conditions were occurring seasonally over a large part of the geographic area now known as the dead zone. The long-term trends in the PEB index are consistent with the 20th-century observational and proxy data for low oxygen and hypoxia. ?? 2009 US Government.

  19. Canada's Dominion Astrophysical Observatory and the rise of 20th Century Astrophysics and Technology

    NASA Astrophysics Data System (ADS)

    Hesser, James E.; Bohlender, David; Crabtree, Dennis

    2015-08-01

    Construction of Canada’s Dominion Astrophysical Observatory (DAO) commenced in 1914 with first light on 6 May 1918. Its varied, rich contributions to the astronomical heritage of the 20th century continue into the 21st century. The first major research observatory built with public funding on the West Coast of North America, it was Canada’s first ‘big science’ project. DAO welcomed scientists from around the world to use its 1.8m telescope designed by John Stanley Plaskett working in close collaboration with the Warner and Swasey Company of Cleveland, OH. Their original design was copied seven times around the globe, the last occasion being in the 1960s. From Day 1 the DAO welcomed the public for viewing and interaction with the small scientific staff whose early efforts would today be characterized as ‘Key Projects’. Those efforts included measuring the radial velocities of O and B stars that, interpreted through Oort’s ideas of differential rotation, determined the most reliable estimate of the size and mass of the Milky Way available until radio astronomical techniques emerged in the 1950s. The first organic molecule in interstellar space, CH, was discovered by a DAO astronomer. The first, very puzzling estimate of ~3K for the temperature of interstellar space was deduced from interstellar CN observations a year after interstellar CH and CN were discovered. DAO’s heritage of innovative instrumentation continues to the present day where expertise in optically efficient, mechanically stable spectrographs and adaptive optics are much in evidence at Mauna Kea’s CFHT, Gemini and Subaru observatories. In 2009 the DAO was designated a National Historic Site. This presentation will draw links between DAO, developments of Canadian astronomy and the emergence of Mauna Kea as an exceptional global astronomical reserve.

  20. Phenology in Germany in the 20th century : methods, analyses and models

    NASA Astrophysics Data System (ADS)

    Schaber, Jörg

    2002-07-01

    The length of the vegetation period (VP) plays a central role for the interannual variation of carbon fixation of terrestrial ecosystems. Observational data analysis has indicated that the length of the VP has increased in the last decades in the northern latitudes mainly due to an advancement of bud burst (BB). This phenomenon has been widely discussed in the context of Global Warming because phenology is correlated to temperatures. Analyzing the patterns of spring phenology over the last century in Southern Germany provided two main findings: - The strong advancement of spring phases especially in the decade before 1999 is not a singular event in the course of the 20th century. Similar trends were also observed in earlier decades. Distinct periods of varying trend behavior for important spring phases could be distinguished. - Marked differences in trend behavior between the early and late spring phases were detected. Early spring phases changed as regards the magnitude of their negative trends from strong negative trends between 1931 and 1948 to moderate negative trends between 1948 and 1984 and back to strong negative trends between 1984 and 1999. Late spring phases showed a different behavior. Negative trends between 1931 and 1948 are followed by marked positive trends between 1948 and 1984 and then strong negative trends between 1984 and 1999. This marked difference in trend development between early and late spring phases was also found all over Germany for the two periods 1951 to 1984 and 1984 to 1999. The dominating influence of temperature on spring phenology and its modifying effect on autumn phenology was confirmed in this thesis. However, - temperature functions determining spring phenology were not significantly correlated with a global annual CO2 signal which was taken as a proxy for a Global Warming pattern. - an index for large scale regional circulation patterns (NAO index) could only to a small part explain the observed phenological variability in

  1. Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

    USGS Publications Warehouse

    Tortorelli, Robert L.

    2008-01-01

    Water Year 2006 (October 1, 2005, to September 30, 2006) was a year of extreme hydrologic drought and the driest year in the recent 2002-2006 drought in Oklahoma. The severity of this recent drought can be evaluated by comparing it with four previous major hydrologic droughts, water years 1929-41, 1952-56, 1961-72, and 1976-81. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, completed an investigation to summarize the Water Year 2006 hydrologic drought and compare it to the four previous major hydrologic droughts in the 20th century. The period of water years 1925-2006 was selected as the period of record because before 1925 few continuous record streamflow-gaging sites existed and gaps existed where no streamflow-gaging sites were operated. Statewide annual precipitation in Water Year 2006 was second driest and statewide annual runoff in Water Year 2006 was sixth driest in the 82 years of record. Annual area-averaged precipitation totals by the nine National Weather Service Climate Divisions from Water Year 2006 are compared to those during four previous major hydrologic droughts to show how rainfall deficits in Oklahoma varied by region. Only two of the nine climate divisions, Climate Division 1 Panhandle and Climate Division 4 West Central, had minor rainfall deficits, while the rest of the climate divisions had severe rainfall deficits in Water Year 2006 ranging from only 65 to 73 percent of normal annual precipitation. Regional streamflow patterns for Water Year 2006 indicate that Oklahoma was part of the regionwide below-normal streamflow conditions for Arkansas-White-Red River Basin, the sixth driest since 1930. The percentage of long-term stations in Oklahoma (with at least 30 years of record) having below-normal streamflow reached 80 to 85 percent for some days in August and November 2006. Twelve long-term streamflow-gaging sites with periods of record ranging from 62 to 78 years were selected to show how streamflow

  2. The Loss of Balance between the Art and Science of Management: Observations on the British Experience of Education for Management in the 20th Century

    ERIC Educational Resources Information Center

    Guerriero Wilson, Robbie

    2015-01-01

    This essay considers the developments in education for management in 20th-century Britain. In the late 19th and early 20th centuries, that is, the highpoint of the United Kingdom's economic success, management was considered more of an art than a science, and formal education specifically for management was limited. After the Second World…

  3. [Occult medicine in the 20th century: pharmacotherapy by Demeter Georgievitz-Weitzer, known as Surya (1873 - 1949)].

    PubMed

    Helmstädter, Axel

    2011-01-01

    Demeter Georgievitz-Weitzer (1873-1949), called "Surya", Sanskrit for "sun", was an important representative of medical occultism in the first half of the 20th century. He worked as a journal editor and published a 13-volume book series about occult medicine, mainly written by himself. His hypotheses were closely related to the "Lebensreform" movement around 1900. Regarding diagnostics, he relied on astrology, cheiromancy, and clairvoyance, while therapeutics were dominated by diet and spagyric remedies according to Cesare Mattei (1809-1896) and Carl-Friedrich Zimpel (1801-1879). In his later years, he developed his own healing system, initially comprising eight, later only two preparations. Surya remedies were commercially available until the end of the 20th century, PMID:22822609

  4. Lessons Learned and Present Day Challenges of Addressing 20th Century Radiation Legacies of Russia and the United States

    SciTech Connect

    KRISTOFZSKI, J.G.

    2000-10-26

    The decommissioning of nuclear submarines, disposal of highly-enriched uranium and weapons-grade plutonium, and processing of high-level radioactive wastes represent the most challenging issues facing the cleanup of 20th century radiation legacy wastes and facilities. The US and Russia are the two primary countries dealing with these challenges, because most of the world's fissile inventory is being processed and stored at multiple industrial sites and nuclear weapons production facilities in these countries.

  5. ​​​History of Cholera Outbreaks in Iran during the 19th and 20th Centuries

    PubMed Central

    Azizi, MH; Azizi, F

    2010-01-01

    Cholera is an acute infectious disease with high mortality if left untreated. Historically, between the 19th and 20th centuries seven great pandemics of cholera occurred and worldwide, thousands of people died. Based on an old theory, cholera was considered an air-born disease and the emergence of its outbreaks were attributed to bad weather or miasma. However later in the 18th century, British physician John Snow (1813-1858) explained the association of a terrible cholera outbreak in London in 1849 to contamination of the drinking water supply with human excreta. Despite his finding, the causative agent of this dreaded illness was unidentified until later in the 19th century. In 1854, Filippo Pacini (1812-1883) an anatomist from Italy and then in 1883, Robert Koch (1843-1910) the German bacteriologist, discovered ‘vibrio cholerae’ as the etiologic agent. During the major pandemics of cholera in 19th and 20th centuries this illness reached Iran and led to vast depopulation and a crucial impact on the country’s socioeconomic status. Poor public health conditions, lack of a well-organized public health authority for implementing preventive and quarantine measures as well as Iran’s specific geographic location were the main facilitating factors of the emergence of various epidemics, including cholera in Iran. The present paper briefly reviews the cholera outbreaks in Iran during the 19th and 20th centuries. PMID:25197514

  6. The little death: Rigoni-Stern and the problem of sex and cancer in 20th-century biomedical research.

    PubMed

    Aviles, Natalie B

    2015-06-01

    Approaches to the organization and conduct of cancer research changed dramatically throughout the 20th century. Despite marked differences between the epidemiological approaches of the first half of the century and molecular techniques that gained dominance in the 1980s, prominent 20th-century researchers investigating the link between sexual activity and anogenital cancers continuously invoked the same 1842 treatise by Italian surgeon Domenico Rigoni-Stern, who is said to originate the problem of establishing a causal link between sex and cancer. In this article, I investigate 20th-century references to Rigoni-Stern as a case of a broader phenomenon: scientists situating their work through narratives of venerated ancestors, or originators. By explaining shifting versions of originator narratives in light of their authors' cultural context and research practices, we can reimagine as meaningful cultural symbols the references that previous scholars have treated as specious rhetorical maneuvers. In this case, references to Rigoni-Stern provide an interpretive anchor for American scientists to construct continuity between their work and a diverse historical legacy of cancer research. PMID:26477198

  7. The controversial early brightening in the first half of 20th century: A contribution from pyrheliometer measurements in Madrid (Spain)

    NASA Astrophysics Data System (ADS)

    Antón, M.; Vaquero, J. M.; Aparicio, A. J. P.

    2014-04-01

    A long-term decrease in downward surface solar radiation from the 1950s to the 1980s ("global dimming") followed by a multi-decadal increase up to the present ("brightening") has been detected in many regions worldwide. In addition, some researchers have suggested the existence of an "early brightening" period in the first half of the 20th century. However, this latter phenomenon is an open issue due to the opposite results found in literature and the scarcity of solar radiation data during this period. This paper contributes to this relevant discussion analyzing, for the first time in Southern Europe, the atmospheric column transparency derived from pyrheliometer measurements in Madrid (Spain) for the period 1911-1928. This time series is one of the three longest datasets during the first quarter of the 20th century in Europe. The results showed the great effects of the Katmai eruption (June 1912, Alaska) on transparency values during 1912-1913 with maximum relative anomalies around 8%. Outside the period affected by this volcano, the atmospheric transparency exhibited a stable behavior with a slight negative trend without any statistical significance on an annual and seasonal basis. Overall, there is no evidence of a possible early brightening period in direct solar radiation in Madrid. This phenomenon is currently an open issue and further research is needed using the few sites with available experimental records during the first half of the 20th century.

  8. Possible role of the dimming/brightening in observed temperatures across Europe since the second half of the 20th century

    NASA Astrophysics Data System (ADS)

    van den Besselaar, E. J. M.; Sanchez-Lorenzo, A.; Wild, M.; Klein Tank, A. M. G.

    2012-04-01

    The surface solar radiation (SSR) is the fundamental source of energy in the climate system, and consequently the source of life on our planet, due to its central role in the surface energy balance. Therefore, a significant impact on temperatures is expected due to the widespread dimming/brightening phenomenon observed since the second half of the 20th century (Wild, 2009). Previous studies pointed out the effects of SSR trends in temperatures series over Europe (Makowski et al., 2009; Philipona et al., 2009), although the lack of long-term SSR series limits these results. This work describes an updated sunshine duration (SS) dataset compiled by the European Climate Assessment and Dataset (ECA&D) project based on around 300 daily time series over Europe covering the 1961-2010 period. The relationship between the SS and temperature series is analysed based on four temperature variables: maximum (TX), minimum (TN) and mean temperature (TG), as well as the diurnal temperature range (DTR). Regional and pan-European mean series of SS and temperatures are constructed. The analyses are performed on annual and seasonal scale, and focusing on the interannual and decadal agreement between the variables. The results show strong positive correlations on interannual scales between SS and temperatures over Europe, especially for the DTR and TX during the summer period and regions in Central Europe. Interestingly, the SS and temperatures series show a tendency towards higher correlations in the smoothed series, both for different regions and temperature variables. These results confirm the relationship between temperature and SS trends over Europe since the second half of the 20th century, which has been speculated to partially decrease (increase) temperatures during the dimming (brightening) period (Makowski et al., 2009; Wild, 2009). Further research is needed to confirm this cause-effect relationship currently found only using correlation analysis.

  9. Impacts of 20th century aerosol emissions on the South Asian monsoon in the CMIP5 models

    NASA Astrophysics Data System (ADS)

    Guo, L.; Turner, A. G.; Highwood, E. J.

    2014-12-01

    Comparison of single-forcing varieties of 20th century historical experiments in a subset of models from the Fifth Coupled Model Intercomparison Project (CMIP5) reveals that South Asian summer monsoon rainfall increases towards the present day in Greenhouse Gas (GHG)-only experiments with respect to pre-industrial levels, while it decreases in anthropogenic aerosol-only experiments. Comparison of these single-forcing experiments with the all-forcings historical experiment suggests aerosol emissions have dominated South Asian monsoon rainfall trends in recent decades, especially during the 1950s to 1970s. The variations in South Asian monsoon rainfall in these experiments follows approximately the time-evolution of inter-hemispheric temperature gradient over the same period, suggesting a contribution from the large-scale background state relating to the asymmetric distribution of aerosol emissions about the equator. By examining the twenty-five available all-forcings historical experiments, we show that models including aerosol indirect effects dominate the negative rainfall trend. Indeed, models including only the direct radiative effect of aerosol show an increase in monsoon rainfall, consistent with the dominance of increasing greenhouse gas emissions and planetary warming on monsoon rainfall in those models. For South Asia, reduced rainfall in the models with indirect effects is related to decreased evaporation at the land surface rather than from anomalies in horizontal moisture flux, suggesting the impact of indirect effects on local aerosol emissions. This is confirmed by examination of aerosol loading and cloud droplet number trends over the South Asia region. Thus while remote aerosols and their asymmetric distribution about the equator play a role in setting the inter-hemispheric temperature distribution on which the South Asian monsoon, as one of the global monsoons, operates, the addition of indirect aerosol effects acting on very local aerosol emissions

  10. Impacts of 20th century aerosol emissions on the South Asian monsoon in the CMIP5 models

    NASA Astrophysics Data System (ADS)

    Guo, L.; Turner, A. G.; Highwood, E. J.

    2015-06-01

    Comparison of single-forcing varieties of 20th century historical experiments in a subset of models from the Fifth Coupled Model Intercomparison Project (CMIP5) reveals that South Asian summer monsoon rainfall increases towards the present day in Greenhouse Gas (GHG)-only experiments with respect to pre-industrial levels, while it decreases in anthropogenic aerosol-only experiments. Comparison of these single-forcing experiments with the all-forcings historical experiment suggests aerosol emissions have dominated South Asian monsoon rainfall trends in recent decades, especially during the 1950s to 1970s. The variations in South Asian monsoon rainfall in these experiments follows approximately the time evolution of inter-hemispheric temperature gradient over the same period, suggesting a contribution from the large-scale background state relating to the asymmetric distribution of aerosol emissions about the equator. By examining the 24 available all-forcings historical experiments, we show that models including aerosol indirect effects dominate the negative rainfall trend. Indeed, models including only the direct radiative effect of aerosol show an increase in monsoon rainfall, consistent with the dominance of increasing greenhouse gas emissions and planetary warming on monsoon rainfall in those models. For South Asia, reduced rainfall in the models with indirect effects is related to decreased evaporation at the land surface rather than from anomalies in horizontal moisture flux, suggesting the impact of indirect effects on local aerosol emissions. This is confirmed by examination of aerosol loading and cloud droplet number trends over the South Asia region. Thus, while remote aerosols and their asymmetric distribution about the equator play a role in setting the inter-hemispheric temperature distribution on which the South Asian monsoon, as one of the global monsoons, operates, the addition of indirect aerosol effects acting on very local aerosol emissions also

  11. Europe experienced a "warming hole" in autumn in the second half of the 20th century

    NASA Astrophysics Data System (ADS)

    Cahynova, M.; Pokorna, L.; Huth, R.

    2012-12-01

    Recent global warming has not been ubiquitous - there might be seasons, regions, and time periods with clearly discernible zero or downward air temperature trends. Regions that are not warming or are even cooling - also known as "warming holes" - have been previously detected mainly in autumn in the second half of the 20th century in large parts of North America as well as in central and eastern Europe. In this study we use daily maximum and minimum temperature (TX and TN, respectively) and daily temperature range (DTR) at 136 stations from the ECA&D database in Europe and the Mediterranean in the period 1961-2000 to precisely locate their seasonal and sub-seasonal trends in space and within the course of the year, and to assess the effect of circulation changes on these observed trends. Linear trends are calculated for moving "seasons" of differing lengths (10, 20, 30, 60, and 90 days), each shifted by one day. Thus we obtain 365 values of "moving trends" for each station and each variant of season length. The day-to-day variability of these trends is greatest for short "seasons" of 10 and 20 days. Trends of the 90-day seasons are the most stable throughout the year and also bear the lowest trend magnitudes. Cluster analysis of the annual course of "moving trends" reveals relatively well-defined regions with similar trend behavior. Over most of Europe, the observed warming is greatest in winter, and the highest trend magnitudes are reached by TN in eastern Europe. Two regions stand out of this general picture: in Iceland and the Mediterranean, winter shows almost no trends, while in summer we see a pronounced warming. Significant autumn cooling centered on mid-November was found in eastern and southeastern Europe for both TX and TN; in many other regions trends are close to zero in the same period. Other clearly non-warming (or even cooling) periods occur in western and central Europe in April and June. Trends of DTR are largely inconclusive and no general picture

  12. Could a 1755-like tsunami reach the French Atlantic coastline? Constraints from 20th century observations and numerical modeling.

    NASA Astrophysics Data System (ADS)

    Allgeyer, S.; Daubord, C.; Hébert, H.; Loevenbruck, A.; Schindelé, F.; Madariaga, R.

    2012-04-01

    The tsunami generated by the 1st November 1755 (Mw ~8.5) earthquake off Portugal affected mainly the coasts of the Iberian Peninsula and Northwest Morocco, and was observed in some places on the North Atlantic coasts, towards the West Indies, but also towards Ireland and the Great Britain, in Cornwall. However, no evidence of observation were found along French Atlantic coastline so far. In a first step, to determine whether there could be effects due to tsunamis on the French coastline, we conducted a study to search for actual tsunamis signals in all historical tide gauge stations of the French Atlantic coast available during the 20th century, specifically for the 1969 and 1975 tsunamis that were well observed in Portugal. Because many recordings are available from the French Hydrographic Service in La Rochelle (west French Atlantic coastline), we focus our study on this harbor. The analysis of these historical tide gauge data shows no evidence for tsunamis in La Rochelle, neither in 1969 or in 1975. Then, to confirm this lack of tsunami, we simulate the tsunamis from the 1969 and 1975 sources, using non linear shallow water equations and a series of imbricated bathymetric grids focusing to the French coastline, and then towards the harbor of La Rochelle: the modeling results confirm unnoticeable amplitudes. In the following step, tsunamis from three different scenarios for the 1755 earthquake have been similarly modeled to estimate the impact of such a tsunami on the French Atlantic coast, with a focus on La Rochelle harbor. The results show that, while the harbor is well protected (amplitudes computed on a synthetic tide gage in the harbor do not exceed 20 to 30 cm crest-to-trough) several areas may have undergone a more important, yet moderate impact, from 0.5 to 1 m, especially in the western part of the island of Ré and the northern coast of the island of Oléron. This may have caused possible local inundations in lowland areas, all the more since the tide

  13. Coupled Climate Model Simulations of Large-scale Eastern Boundary Current Forcing During the Mid-Holocene and Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Diffenbaugh, N. S.

    2005-12-01

    We analyze coupled atmosphere-ocean general circulation model (GCM) output from the IPCC Fourth Assessment and the Paleoclimate Modelling Intercomparison Project. We focus on three time periods: the 20th century, 6 ka and 21 ka. The coupled GCMs capture the basic late-20th century seasonal structure of large-scale sea level pressure and wind forcing in the four major eastern boundary current regions (California, Canary, Humbolt and Benguela). There are moderate biases in the simulation of late-20th century inter-annual variability of large-scale sea level pressure and wind forcing, and substantial biases in the simulation of late-20th century mean monthly coastal winds. The coupled models show large changes in the magnitude of mean sea level pressure forcing in the 21 ka simulations and smaller changes in the 6 ka simulations. However, the magnitude of changes in inter-annual variability of sea level pressure forcing is similar in the 21 ka and 6 ka simulations. These and related analyses will aid in the evaluation of existing hypotheses of the response of eastern boundary currents to changes in external climate forcing. They will also help to create new testable hypotheses of eastern boundary current response and, in conjunction with proxy records, allow for a more sophisticated understanding of the mechanisms that shaped the late-Quaternary evolution of these important upwelling systems.

  14. Hydrologic drought of water year 2011 compared to four major drought periods of the 20th century in Oklahoma

    USGS Publications Warehouse

    Shivers, Molly J.; Andrews, William J.

    2013-01-01

    Water year 2011 (October 1, 2010, through September 30, 2011) was a year of hydrologic drought (based on streamflow) in Oklahoma and the second-driest year to date (based on precipitation) since 1925. Drought conditions worsened substantially in the summer, with the highest monthly average temperature record for all States being broken by Oklahoma in July (89.1 degrees Fahrenheit), June being the second hottest and August being the hottest on record for those months for the State since 1895. Drought conditions continued into the fall, with all of the State continuing to be in severe to exceptional drought through the end of September. In addition to effects on streamflow and reservoirs, the 2011 drought increased damage from wildfires, led to declarations of states of emergency, water-use restrictions, and outdoor burning bans; caused at least $2 billion of losses in the agricultural sector and higher prices for food and other agricultural products; caused losses of tourism and wildlife; reduced hydropower generation; and lowered groundwater levels in State aquifers. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted an investigation to compare the severity of the 2011 drought with four previous major hydrologic drought periods during the 20th century – water years 1929–41, 1952–56, 1961–72, and 1976–81. The period of water years 1925–2011 was selected as the period of record because few continuous record streamflow-gaging stations existed before 1925, and gaps in time existed where no streamflow-gaging stations were operated before 1925. In water year 2011, statewide annual precipitation was the 2d lowest, statewide annual streamflow was 16th lowest, and statewide annual runoff was 42d lowest of those 87 years of record. Annual area-averaged precipitation totals by the nine National Weather Service climate divisions from water year 2011 were compared to those during four previous major hydrologic drought

  15. Extension of the SIM Hydrometeorological Reanalysis Over the Entire 20th Century by Combination of Observations and Statistical Downscaling

    NASA Astrophysics Data System (ADS)

    Minvielle, M.; Céron, J.; Page, C.

    2013-12-01

    The SAFRAN-ISBA-MODCOU (SIM) system is a combination of three different components: an atmospheric analysis system (SAFRAN) providing the atmospheric forcing for a land surface model (ISBA) that computes surface water and energy budgets and a hydrological model (MODCOU) that provides river flows and level of several aquifers. The variables generated by the SIM chain constitute the SIM reanalysis and the current version only covers the 1958-2012 period. However, long climate datasets are required for evaluation and verification of climate hindcasts/forecasts and to isolate the contribution of natural decadal variability from that of anthropogenic forcing to climate variations. The aim of this work is to extend of the fine-mesh SIM reanalysis to the entire 20th century, especially focusing on temperature and rainfall over France, but also soil wetness and river flows. This extension will first allow a detailed investigation of the influence of decadal variability on France at very fine spatial scales and will provide crucial information for climate model evaluation. Before 1958, the density of available observations from Météo-France necessary to force SAFRAN (rainfall, snow, wind, temperature, humidity, cloudiness) is much lower than today, and not sufficient to produce a correct SIM reanalysis. That's why is has been decided to use the available atmospheric observations over the past decades combined to a statistical downscaling algorithm to overcome the lack of observations. The DSCLIM software package implemented by the CERFACS and using a weather typing based statistical methodology will be used as statistical downscaling method to reconstruct the atmospheric variables necessary to force the ISBA-MODCOU hydrological component. The first stage of this work was to estimate and compare the bias and strengths of the two approaches in their ability to reconstruct the past decades. In this sense, SIM hydro-meteorological experiments were performed for some recent

  16. Carbon cycling in extratropical terrestrial ecosystems of the Northern Hemisphere during the 20th century: A modeling analysis of the influences of soil thermal dynamics

    USGS Publications Warehouse

    Zhuang, Q.; McGuire, A.D.; Melillo, J.M.; Clein, J.S.; Dargaville, R.J.; Kicklighter, D.W.; Myneni, R.B.; Dong, J.; Romanovsky, V.E.; Harden, J.; Hobbie, J.E.

    2003-01-01

    There is substantial evidence that soil thermal dynamics are changing in terrestrial ecosystems of the Northern Hemisphere and that these dynamics have implications for the exchange of carbon between terrestrial ecosystems and the atmosphere. To date, large-scale biogeochemical models have been slow to incorporate the effects of soil thermal dynamics on processes that affect carbon exchange with the atmosphere. In this study we incorporated a soil thermal module (STM), appropriate to both permafrost and non-permafrost soils, into a large-scale ecosystem model, version 5.0 of the Terrestrial Ecosystem Model (TEM). We then compared observed regional and seasonal patterns of atmospheric CO2 to simulations of carbon dynamics for terrestrial ecosystems north of 30??N between TEM 5.0 and an earlier version of TEM (version 4.2) that lacked a STM. The timing of the draw-down of atmospheric CO2 at the start of the growing season and the degree of draw-down during the growing season were substantially improved by the consideration of soil thermal dynamics. Both versions of TEM indicate that climate variability and change promoted the loss of carbon from temperate ecosystems during the first half of the 20th century, and promoted carbon storage during the second half of the century. The results of the simulations by TEM suggest that land-use change in temperate latitudes (30-60??N) plays a stronger role than climate change in driving trends for increased uptake of carbon in extratropical terrestrial ecosystems (30-90??N) during the recent decades. In the 1980s the TEM 5.0 simulation estimated that extratropical terrestrial ecosystems stored 0.55 Pg C yr-1. with 0.24 Pg C yr-1 in North America and 0.31 Pg C yr-1 in northern Eurasia. From 1990 through 1995 the model simulated that these ecosystems stored 0.90 Pg C yr-1, with 0.27 Pg C yr-1 stored in North America and 0.63 Pg C yr-1 stored in northern Eurasia. Thus, in comparison to the 1980s, simulated net carbon storage in the

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

    NASA Astrophysics Data System (ADS)

    Bian, Qiying; Lu, Riyu

    2013-04-01

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

  18. The influence of inequality on the standard of living: worldwide anthropometric evidence from the 19th and 20th centuries.

    PubMed

    Blum, Matthias

    2013-12-01

    We provide empirical evidence on the existence of the Pigou-Dalton principle. The latter indicates that aggregate welfare is - ceteris paribus - maximized when incomes of all individuals are equalized (and therefore marginal utility from income is as well). Using anthropometric panel data on 101 countries during the 19th and 20th centuries, we determine that there is a systematic negative and concave relationship between height inequality and average height. The robustness of this relationship is tested by means of several robustness checks, including two instrument variable regressions. These findings help to elucidate the impact of economic inequality on welfare. PMID:23352274

  19. International dimensions of higher education in nursing in Canada: tapping the wisdom of the 20th century while embracing possibilities for the 21st century.

    PubMed

    Ogilvie, Linda D; Paul, Pauline; Burgess-Pinto, Elizabeth

    2007-01-01

    New focus on the internationalization of universities occurred in the late 20th century and higher education in nursing has been quick to embrace the opportunities. In this manuscript, writers provide a brief overview of the nursing and more general literature from the late 20th century relating to key dimensions of internationalization, as well as present data from a survey conducted in 1995-96 of the international activities and dimensions at Canadian faculties/schools of nursing. While it is clear that nurses in Canadian universities were engaged in significant international endeavours in the 20th century, the literature and our experience suggest that the extent of such activity has increased substantially in recent years. Discussion centres on examination of how knowledge generated in the 20th century can inform current internationalization initiatives and on identification of key questions that merit consideration as we move forward in the 21st century. PMID:17402933

  20. Changes in the African American female profile as depicted in fashion magazines during the 20th century.

    PubMed

    Yehezkel, Shaul; Turley, Patrick K

    2004-04-01

    This study evaluated changes in the profiles of African American women presented in fashion magazines during the 20th century. Twenty-six variables were measured on a total of 119 profile photographs collected from various fashion magazines published in the 1940s through the 1990s. The photographs were divided into 6 groups corresponding to the decade in which they were published. A 1-way analysis of variance was performed, and between-group differences were examined with a Tukey multiple comparison procedure. Significant between-group differences (P <.01) were found for anteroposterior lip position, nasolabial angle, and interlabial angle, with increased fullness and more anteriorly positioned lips in the more recent decades. No significant differences were found for the frontonasal angle, the nasal tip angle, and the relationship of the chin to the upper face (total facial angle). Esthetic standards for the African-American female profile changed during the 20th century and, similar to the standards for the white profile, show a trend toward fuller and more anteriorly positioned lips. PMID:15067255

  1. Have there been changes in the epidemiology of sexual abuse of children during the 20th century?

    PubMed

    Leventhal, J M

    1988-11-01

    Have there been changes in the epidemiology of sexual abuse of children during the 20th century? To explore this question, a comparison was made between the results of the survey conducted by Alfred Kinsey and colleagues in the 1940s of women in the United States, the majority of whom were born between 1900 and 1929, and the results of more recent studies of the epidemiology of sexual abuse. In Kinsey's study, 24% of 4,441 women reported at least one episode of sexual abuse before adolescence; in 49% of the episodes, the perpetrator was not known to the child and, in 50%, the abuse did not involve bodily contact. These findings are compared to the results of more recent epidemiologic surveys, particularly Russell's study conducted in San Francisco in 1978. Although there are important differences in the methodologies used by Kinsey and Russell, it is likely that changes have occurred in the prevalence and nature of sexual abuse in the 20th century. Russell described a higher prevalence of sexual abuse, a greater proportion of perpetrators who were relatives or adults known to the child, and a greater proportion of serious types of sexual abuse. PMID:3186358

  2. [Reform of the medical education in the early 20th century America and the Flexner Report of 1910].

    PubMed

    Hwang, S I

    1994-01-01

    Reform of the medical education in the early 20th century America caused many consequences in the various aspects of the medical fields as well as the improvement of the medical education itself such as the reinforcement of the laboratory training in the basic science courses and hospital instruction in the clinical courses. The reform brought about the direct or indirect elimination of the irregular sectarian practitioners and the minority groups such as black and women from the medical market place, established the concrete position of the regular physicians in the American society, reinforced the biomedical aspects which would become the general tendency in the 20th century Western medicine. And the author stressed that the reform was neither initiated nor invoked but just accelerated by the so-called Flexner Report of 1910, rather it had been performed through the processes of the interaction and struggle between the various contradictory trends, tendencies, and forces such as american Medical Association (AMA), some leading medical educators and scientists, medical colleges, and philanthropic foundations in the socio-cultural millieu gradually moving to favor the "science". PMID:11618917

  3. The health transition and biological living standards: adult height and mortality in 20th-century Spain.

    PubMed

    Spijker, Jeroen J A; Cámara, Antonio D; Blanes, Amand

    2012-07-01

    This paper seeks new insights concerning the health transition in 20th century Spain by analyzing both traditional (mortality-based) and alternative (anthropometric-based) health indicators. Data were drawn from national censuses, vital and cause-of-death statistics and seven National Health Surveys dating from 1987 to 2006 (almost 100,000 subjects aged 20-79 were used to compute cohort height averages). A multivariate regression analysis was performed on infant mortality and economic/historical dummy variables. Our results agree with the general timing of the health transition process in Spain as has been described to date insofar as we document that there was a rapid improvement of sanitary and health care related factors during the second half of the 20th century reflected by a steady decline in infant mortality and increase in adult height. However, the association between adult height and infant mortality turned out to be not linear. In addition, remarkable gender differences emerged: mean height increased continuously for male cohorts born after 1940 but meaningful improvements in height among female cohorts was not attained until the late 1950s. PMID:21924964

  4. The Destiny of an Eastern Observatory Follows the Dramatic One of this Part of Europe During the 20th Century

    NASA Astrophysics Data System (ADS)

    Stavinschi, M.

    Founded at the dawn of the 20th century (1908), the Astronomical Observatory of Bucharest had an evolution that followed the destiny of its country. After about half a century along which it lives the usual life of any European institution for research and education, it leaves the education after the World War II, becoming an institute of the Academy. A short period of progress is followed by an unprecedented, total isolation, even from the neighbouring countries. The fall of the communist system in the last decade of the 20th century brings new endeavours, but also a hard competition with the worldwide astronomy. What is important is that in each situation the Romanian astronomers have found the interior resources to resist and to keep the national astronomy competitive, at least as regards some of its fields. Moreover, by setting the South-Eastern Branch of the European Astronomical Society, it wishes to contribute to the finding of local solutions, with the goal of increasing the level of astronomy in countries that face the same problems, the same difficulties.

  5. [The creation of hospitals by charities in Minas Gerais (Brazil) from 18th to 20th century].

    PubMed

    Marques, Rita de Cássia

    2011-01-01

    This article is the fruit of research into the cultural heritage of healthcare in Minas Gerais (Brazil) and explores the construction of hospitals supported by Catholic charities from the 18th to 20th century. Catholicism has always been strong in Minas Gerais, partly because the Portuguese Crown prohibited the free travel of priests, who were suspected of illegally trading in gold from the mines. A brotherhood was responsible for creating the first Santa Casa, in Vila Rica. Another very important religious group in Brazil, the Vincentians, was also devoted to charitable works and propagated the ideas on charity of Frederico Ozanan, based on the work of St. Vincent de Paul. This group comprised both a lay movement, supported by conferences organized by the St. Vincent de Paul Society, and a religious order, the Vincentian priests and nuns. Catholic physicians make up the third group studied here, organized in a professional association promoted by the Catholic Church. The brotherhoods, Vincentians, and associations, with their Santa Casas, represent a movement that is recognized worldwide. The enormous Catholic participation in these charitable works brought in the physicians, who would often make no charge and exerted efforts to create hospitals that served the population. Although the capital of Minas Gerais was the creation of republicans and positivists in the 20th century, with their ideas of modernity, it remained dependent on Christian charity for the treatment of the poor. PMID:21936227

  6. Can Earth System Models Explain the observed 20th Century Global Carbon Sink?

    NASA Astrophysics Data System (ADS)

    Stouffer, R. J.; Shevliakova, E.; Malyshev, S.; Krasting, J. P.; Pacala, S.; Dunne, J. P.; John, J. G.

    2012-12-01

    Various authors have estimated the net global land carbon flux as a residual from the global budget of atmospheric, oceanic and fossil fuel carbon fluxes. Recently, Tans (2009) used this method to estimate the globally averaged net land carbon inventory changes method from 1850 to near present day. Using ocean model estimates of the oceanic carbon fluxes, he showed the land being a net source of carbon until around 1940, but after that becoming a net sink, with an uncertainty dominated by the net oceanic carbon flux trajectory (~15%; Sabine et al 2004). Recently Ballantyne et al (2012) produced updated estimates of the net carbon fluxes changes from 1960 until present day. They show that the net carbon flux uptake, land plus ocean, increases from around 2 PgC/yr in 1960 to about 5 PgC/yr in 2010. We compare these observationally based estimates with results from the GFDL Earth System Models (ESMs). We show that both GFDL ESMs store too much carbon in the atmosphere, about a 10 to 20 ppm error by 2005. The models have slightly higher mean values than the Tans (2009) oceanic carbon storage changes but fall within the Sabine et al. (2004) uncertainty estimate. While the general shape of the net land carbon changes in Tans (2009) is well simulated by the ESMs, the ESM sign change in land flux occurs about 15-25years later. By 2010, the models simulate the oceanic carbon uptake as ~2.7 PgC/yr, and the land uptake as ~1 PgC/yr for a total of ~4PgC/yr. The land uptake value varies with ensemble member giving evidence for the role of variability in understanding the past carbon changes. This analysis gives us confidence in the models estimates of the climate-carbon feedbacks. The model results will then be analyzed to determine the various causes of those changes.

  7. Trends in 20th century drought characteristics over the continental United States

    NASA Astrophysics Data System (ADS)

    Andreadis, K. M.; Lettenmaier, D. P.

    2005-12-01

    A simulated data set of hydroclimatalogical variables produced by the Variable Infiltration Capacity (VIC) macro-scale hydrology model, forced by a temporally-consistent long-term (1915-2003) meteorologic data set, is used to examine for potential trends in drought characteristics over the continental United States. The VIC model has been extensively validated over many continental scale river basins and various climates, and successfully used to reproduce a U.S. drought history for the same 1915-2003 period. Drought characteristics, such as intensity and duration, are estimated using gridded precipitation (forcings, directly related to observations), model-derived soil moisture, and model-derived runoff expressed as percentiles of the respective climatology at each model grid cell. Trend significance is determined using the non-parametric seasonal Mann-Kendall test on a monthly time-step. Different thresholds are used to examine droughts of varying severity (moderate to extreme), with the duration of an event defined as the number of months that soil moisture/runoff percentiles are below the threshold value. Trends in drought characteristics are examined in conjunction with trends in precipitation, soil moisture and streamflow data. In addition, streamflow data from the HCDN station network are used for verification of the trends found in the simulated runoff time series. The results show that there is a statistically significant increasing trend in both soil moisture and streamflow for the majority of the study domain on an annual basis, which generally corresponds to increasing trends in precipitation. Furthermore, examination of seasonal trends reveals strong spatial clustering of both wetting and drying trends. As a result, areas affected by drought appear to decrease in general. However, droughts have appeared to intensify in certain regions of the country. Drought durations, in general, do not show any significant trend over most of the domain. Finally, the

  8. Dimming over the Oceans: Transient Anthropogenic Aerosol Plumes in the 20th Century

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin

    2015-04-01

    Anthropogenic aerosols reduce incoming surface solar radiation (SSR), but the magnitude of this effect for reducing sea surface temperature (SST) is still debated. Using simulations from the global climate model ECHAM5 with the Hamburg Aerosol Module (HAM) and prescribed SSTs, we quantify anthropogenic aerosol dimming over sea surfaces by comparing ensembles, which only differ in anthropogenic aerosol emissions. We isolate the anthropogenic aerosol effect on SSR with sufficiently large ensemble sizes to provide statistically significant results. The following simulation results are obtained: Dimming plumes extend from their source regions with clear seasonality. The latter is predominantly shaped by atmospheric circulation, while interdecadal changes follow the gradual increase in anthropogenic aerosol emissions. Comparing the 1990s with the 1870s, on average, 9.4% (clearsky SSR) or 15.4% (allsky SSR) of the entire ocean surface was affected by anthropogenic aerosol dimming larger than -4 W m-2 (annual mean). Comparing the same time periods, global average anthropogenic dimming over oceans is -2.3 W m-2and -3.4 W m-2 for clearsky and allsky SSR, respectively. Surface dimming is hemispherically asymmetrical with stronger Northern Hemispheric dimming by 2.3 W m-2 and 4.5 W m-2 for clearsky and allsky SSR, respectively. Zonal average clearsky dimming reaches its maximum (5.5 W m-2 ) near the Equator. Allsky dimming peaks at 40° N (-8 W m-2 ) and is regionally larger than clearsky dimming. Regionally, surface dimming can go beyond -20 W m-2 (clearsky) and -40 W m-2 (allsky). Results are a contribution towards better quantifying spatially heterogeneous and time-dependent anthropogenic dimming effects on SSTs.

  9. Changes in the geodiversity of Dutch peatlands inferred from 19th and 20th century landscape paintings

    NASA Astrophysics Data System (ADS)

    Jungerius, Pieter Dirk; van den Ancker, Hanneke; Wevers, Nina

    2013-04-01

    Geodiversity is the natural and cultural range of geological, geomorphological and soil features. We analysed the large database of 19th and early 20th century paintings of Simonis and Buunk (www.Simonis-Buunk.com) to track changes in the geodiversity of Dutch peatlands since pre-photographic times. Peat dominated in two of the eight main landscapes of the Netherlands: the Lowland peats in the Holocene west and the Highland peats in the sandy Pleistocene eastern parts. Painters were mainly attracted by the lowland peats. Since more than thousand years, peat plays a major role in Dutch military security, economy, ecology and cultural life. Natural variety and cultural use resulted in a geodiversity that is unique in Europe. There are more than 100 place names with 'veen' (= peat), and surnames with 'veen' are common. Proof of the exploitation of peat for salt and fuel exists from the Roman times onwards. In the 9th century, peatlands were drained and reclaimed for growing wheat. Already in the 11th century, it was necessary to build dikes to prevent flooding, to control waterlevels to avoid further oxidation, and to convert landuse to grassland. But subsidence continued, and in the 14th century windmills were needed to drain the lands and pump the water out. In the 16th century industrial peat exploitation fuelled the rise of industries and cities. All this draining and digging caused the peat surface to shrink. The few remaining living peats are conserved by nature organisations. Geodiversity and landscape paintings In the peat landscapes, popular painting motives were high water levels, the grasslands of the 'Green Heart', the winding streams and remaining lakes. The paintings of landscapes where peat had been removed, show watermanagement adaptations: wind mills, different water levels, canals made for the transport of fuel, bridges, tow paths and the 'plassen', i.e. the lakes left after peat exploitation. The droogmakerijen (reclaimed lakes), now 2 to 5 m below

  10. Variation in 20th Century Weather Extremes as a function of Biome

    NASA Astrophysics Data System (ADS)

    Wilson, C. J.; Brunsell, N. A.; Young, C.; Miller, L.

    2012-12-01

    A changing climate has the potential to cause changes in extreme weather. The United States Historical Climate Network (USHCN) data was used to examine extreme heat events, cold snaps and heavy precipitation patterns. Extreme weather events are quantified in terms of the number of occurrences above the 90th percentile as well as the magnitude threshold at which they occur. The Koeppen-Geiger climate classification system was used to relate the temperature and precipitation extremes to the underlying climate zone. Approximately 95 percent of the United States lies within nine Koeppen-Geiger climate zones which consist of three main climate zones: arid, warm temperate and snow. We have found that each climate zone shows a different trend in extreme events since 1900. A Mann-Kendall test shows that stations contained a significant increase or decrease of extreme weather events, depending on season and Koeppen-Geiger zone. In order to assess the significance of the changes over time, the data were broken up into two time series, 1950-1980 and 1980-2011. These two time periods were compared using a paired t-test to assess the significance of possible differences between the time periods. A shift in the magnitude of extreme weather events can be found throughout Koeppen-Geiger zones and differ by specific extreme weather event. The exposure and vulnerability of a change in extreme weather events elevates the risk of major societal impact. In order to prevent future natural catastrophe, it is vital to have a solid understanding of extreme weather.