Soil organic carbon (SOC) is important both for its influence on agricultural productivity and for its role in the carbon cycle. The distribution of SOC is highly variable at the field scale both horizontally and vertically; a portion of SOC's variability can be attributed to differences in vegetative cover and to slope position. This study characterized and compared SOC concentration to a depth of 2 meters across 6 loess-veneered watersheds in the central United States. Data were collected as part of the Shawnee Hills Loess Catenas project, a collaboration between the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service, USDA Forest Service, Purdue University, University of Kentucky, Southern Illinois University at Carbondale, and Illinois State Geological Survey, among others. The study consists of pairs of sites, one under forest cover and one grass cover, located in southern Illinois, southern Indiana, and western Kentucky. Bulk density and SOC data were calculated from genetic horizon samples taken from soil pits laid out as transects along slopes at each site. SOC concentrations were significantly higher under forest cover. Footslopes and toeslopes had significantly higher SOC densities than summits, shoulders, and backslopes. A three-part exponential decay model was the best fit for the relationship between SOC density and depth from the surface. The comparisons and models may be used to more accurately predict SOC concentration and carbon pool size on similar loess-veneered landscapes in the central United States.

No description available.

Muitos negócios possuem exposição às variações climáticas e com poucas alternativas para mitigar este tipo de risco. Nos últimos 20 anos o mercado de derivativos climáticos se desenvolveu principalmente em locais como Canadá, EUA e Europa para transferir os riscos relacionados às variações climáticas para investidores com maior capacidade de absorção, tais como seguradoras, resseguradoras e fundos de investimentos. Este trabalho implementou uma metodologia de precificação destes contratos para a variável temperatura média diária no Brasil. Foram utilizados os dados de 265 estações meteorológicas cadastras no site do BDMEP/INMET, utilizando-se observações diárias durante o período 1970-2012. Enquanto a maior parte dos trabalhos de precificação fora desenvolvida para um local específico, neste estudo buscou-se uma solução mais generalizada e que permitisse aos participantes deste novo mercado balizar suas expectativas de preço para qualquer ponto com uma estação meteorológica no país. O principal desafio para esta abordagem foram as falhas nas séries temporais e para isto desenvolveu-se uma metodologia de preenchimento utilizando as informações do projeto NCEP/NCAR. Cada estação foi submetida ao algoritmo de análise e modelagem das séries de temperatura. Considerou-se \"Sucesso\" (36.2% dos casos) as estações cujo processo de modelagem culminou em um resíduo ruído branco, estacionário e homoscedástico. Por \"Fracasso\" (63.8% das estações) entendem-se os casos que violaram pelo menos uma destas condições. Para a incorporação da tendência nos dados utilizou-se a Regressão Polinomial Local (LOESS). Para a estimação da sazonalidade foi empregada análise espectral e utilizada a série de Fourier. Para o tratamento da autocorrelação serial nos resíduos utilizou-se modelos ARFIMA, que contempla um parâmetro para memória longa do processo. A análise espacial dos resultados sugere uma maior taxa de \"Sucesso\" para a precificação de contratos na região Centro-Sul do país e piores para Norte e Nordeste. O método de preenchimento das falhas não deve ser utilizado indiscriminadamente por todo o país, uma vez que a correlação entre as séries do BDMEP/INMET e NCEP/NCAR não é constante, além de apresentar um claro padrão na dispersão espacial. A precificação dos contratos foi feita pelos métodos de \"Burning cost\", \"Modelagem do Índice\" e \"Modelagem da temperatura média diária\". Para este último caso as temperaturas simuladas apresentaram um viés ligeiramente acima dos dados históricos, podendo causar grandes distorções na precificação dos contratos. Deve-se realizar uma correção dos valores simulados antes da precificação dos contratos. A qualidade e consistência dos dados climáticos representam a maior ameaça para a utilização de derivativos climáticos no país, principalmente na região Cento-Oeste, aonde existem poucas estações meteorológicas, e Nordeste, com baixíssima taxa de \"Sucesso\", mesmo com um razoável número de estações. / Many business are exposed to weather variations and managers did not use to have a tool to avoid it. In the last twenty years, weather derivative markets has developed mainly in Canada, USA and Europe, transferring these risks to investors who are willing and able to assume it and receive a financial compensation for that, such as investment funds, insurance and reinsurance companies. This study developed a methodology to price weather contracts with daily average temperature as underlying. It was used 265 public weather stations from BDMEP/ INMET and data was collected from 1970 up to 2012. While the most part of studies in this area have focused in one or few stations, the goal of this study was to develop a more general pricing tool which would allow assessing weather risk and quoting it at any place in Brazil with an available weather station. The main issue was the gaps that occur so frequently in weather time series data and a methodology using interpolated data from NCEP/NCAR was proposed to deal with it. At the bottom of modelling process, weather stations were classified as \"Success\" (36.2%) or \"Failure\" (63.8%) according to the analysis of residuals. To be considered \"Success\", residuals of a time series must be stationary, homoscedastic and white-noise, i.e., free of autocorrelation. If at least one of these was not reached, the modelling process of this weather station was considered \"Failure\". Detrend data was done using Local Polynomial Regression (LOESS). Seasonality was estimated using spectral analysis and Fourier analysis. Autocorrelation of residuals was incorporated into the model using ARFIMA models, which have a parameter to deal with long memory process. Spatial analysis of results suggests a higher \"Success\" rate for contracts priced in the Center south region and worst results were obtained in North and Northeast. Methodology to fill the gaps should not be used in all situations, once correlation is not constant through the country and has a strong spatial pattern (clustering). Pricing was done using \"Burning cost\", \"Index modelling\" and \"Daily modelling of average temperature\". In this former case, simulated temperature has shown a slightly positive bias, which could create huge differences in prices compared with other models. A correction should be done to these values, to use it for pricing purposes. The quality and consistency of weather data is the main issue to develop a weather market in Brazil, mainly in Center-West region, where there is a small number of weather stations and Northeast with the lowest \"Success\" rate, even with a not so small number of weather stations.

Muitos negócios possuem exposição às variações climáticas e com poucas alternativas para mitigar este tipo de risco. Nos últimos 20 anos o mercado de derivativos climáticos se desenvolveu principalmente em locais como Canadá, EUA e Europa para transferir os riscos relacionados às variações climáticas para investidores com maior capacidade de absorção, tais como seguradoras, resseguradoras e fundos de investimentos. Este trabalho implementou uma metodologia de precificação destes contratos para a variável temperatura média diária no Brasil. Foram utilizados os dados de 265 estações meteorológicas cadastras no site do BDMEP/INMET, utilizando-se observações diárias durante o período 1970-2012. Enquanto a maior parte dos trabalhos de precificação fora desenvolvida para um local específico, neste estudo buscou-se uma solução mais generalizada e que permitisse aos participantes deste novo mercado balizar suas expectativas de preço para qualquer ponto com uma estação meteorológica no país. O principal desafio para esta abordagem foram as falhas nas séries temporais e para isto desenvolveu-se uma metodologia de preenchimento utilizando as informações do projeto NCEP/NCAR. Cada estação foi submetida ao algoritmo de análise e modelagem das séries de temperatura. Considerou-se \"Sucesso\" (36.2% dos casos) as estações cujo processo de modelagem culminou em um resíduo ruído branco, estacionário e homoscedástico. Por \"Fracasso\" (63.8% das estações) entendem-se os casos que violaram pelo menos uma destas condições. Para a incorporação da tendência nos dados utilizou-se a Regressão Polinomial Local (LOESS). Para a estimação da sazonalidade foi empregada análise espectral e utilizada a série de Fourier. Para o tratamento da autocorrelação serial nos resíduos utilizou-se modelos ARFIMA, que contempla um parâmetro para memória longa do processo. A análise espacial dos resultados sugere uma maior taxa de \"Sucesso\" para a precificação de contratos na região Centro-Sul do país e piores para Norte e Nordeste. O método de preenchimento das falhas não deve ser utilizado indiscriminadamente por todo o país, uma vez que a correlação entre as séries do BDMEP/INMET e NCEP/NCAR não é constante, além de apresentar um claro padrão na dispersão espacial. A precificação dos contratos foi feita pelos métodos de \"Burning cost\", \"Modelagem do Índice\" e \"Modelagem da temperatura média diária\". Para este último caso as temperaturas simuladas apresentaram um viés ligeiramente acima dos dados históricos, podendo causar grandes distorções na precificação dos contratos. Deve-se realizar uma correção dos valores simulados antes da precificação dos contratos. A qualidade e consistência dos dados climáticos representam a maior ameaça para a utilização de derivativos climáticos no país, principalmente na região Cento-Oeste, aonde existem poucas estações meteorológicas, e Nordeste, com baixíssima taxa de \"Sucesso\", mesmo com um razoável número de estações. / Many business are exposed to weather variations and managers did not use to have a tool to avoid it. In the last twenty years, weather derivative markets has developed mainly in Canada, USA and Europe, transferring these risks to investors who are willing and able to assume it and receive a financial compensation for that, such as investment funds, insurance and reinsurance companies. This study developed a methodology to price weather contracts with daily average temperature as underlying. It was used 265 public weather stations from BDMEP/ INMET and data was collected from 1970 up to 2012. While the most part of studies in this area have focused in one or few stations, the goal of this study was to develop a more general pricing tool which would allow assessing weather risk and quoting it at any place in Brazil with an available weather station. The main issue was the gaps that occur so frequently in weather time series data and a methodology using interpolated data from NCEP/NCAR was proposed to deal with it. At the bottom of modelling process, weather stations were classified as \"Success\" (36.2%) or \"Failure\" (63.8%) according to the analysis of residuals. To be considered \"Success\", residuals of a time series must be stationary, homoscedastic and white-noise, i.e., free of autocorrelation. If at least one of these was not reached, the modelling process of this weather station was considered \"Failure\". Detrend data was done using Local Polynomial Regression (LOESS). Seasonality was estimated using spectral analysis and Fourier analysis. Autocorrelation of residuals was incorporated into the model using ARFIMA models, which have a parameter to deal with long memory process. Spatial analysis of results suggests a higher \"Success\" rate for contracts priced in the Center south region and worst results were obtained in North and Northeast. Methodology to fill the gaps should not be used in all situations, once correlation is not constant through the country and has a strong spatial pattern (clustering). Pricing was done using \"Burning cost\", \"Index modelling\" and \"Daily modelling of average temperature\". In this former case, simulated temperature has shown a slightly positive bias, which could create huge differences in prices compared with other models. A correction should be done to these values, to use it for pricing purposes. The quality and consistency of weather data is the main issue to develop a weather market in Brazil, mainly in Center-West region, where there is a small number of weather stations and Northeast with the lowest \"Success\" rate, even with a not so small number of weather stations.

Ce mémoire de thèse est consacré à l'étude expérimentale du comportement hydromécanique d'un lœss naturel non saturé effondrable provenant d'un site proche de la ville de Bapaume (nord de la France) dans une zone où des problèmes de tassement le long de la ligne nord du TGV ont été attribués à l'effondrement du lœss, du fait d'infiltrations d'eau. Un nouvel appareil triaxial permettant de mesurer localement l'ensemble des caractéristiques du loess non saturé (déformation, teneur en eau et succion) a été développé. La courbe de rétention d'eau, déterminée à l'aide d'un tensiomètre de haute capacité et de la méthode du papier filtre a fait l'objet d'une attention particulière : elle présente autour de la teneur naturelle une zone sans hystérésis bordée par deux boucles d'hystérésis des côtés secs et humides. L'analyse de la courbe de rétention et du phénomène d'hystérésis a été approfondie grâce à une étude microstructurale réalisée à l'aide de la porosimétrie au mercure et de la microscopie électronique à balayage. Une structure assez complexe composée d'un arrangement métastable de grains de limon secs (probablement liés par la recristallisation du calcaire) et d'une phase argileuse répartie de façon hétérogène a été mise en évidence. L'étude du comportement hydromécanique a compris une investigation de l'effondrement à partir de faibles valeurs de contraintes proches de la contrainte in-situ, à l'aide d'essais oedométriques à taux de déformation constant avec mesures de succion. Le maximum d'effondrement et une dépendance fonction de la vitesse de chargement ont été identifiés. Une campagne d'essais triaxiaux à différentes teneurs en eau constantes avec mesure de succion a permis de déterminer l'allure de la limite élastique du limon naturel dans un diagramme p/q, ainsi que ses variations avec la teneur en eau et la succion et confirmer l'écrouissage en succion / The hydromechanical behaviour of an unsaturated natural loess from Northern France has been studied. Collapse-on-wetting phenomena under constant external load are observed in the in-situ conditions, related to some stability problems detected on the loess foundations of the high speed train line that links Paris to Brussels. A new triaxial apparatus with complete local monitoring of unsaturated properties (strains, water content and suction) of this loess has been developed. The water retention curve of loess, obtained by using an in-house constructed high capacity tensiometer and the filter paper method, shows a special behaviour, with a non-hysteresis zone detected around the natural hydric state bordered by two hysteresis loops at the dry and wet sides of the curve. Further analysis of the water retention curve and of the hysteresis phenomena were conducted by means of a microstructure study made by mercury intrusion porosimetry and scanning electron microscope observations. The complex structure of loess is highlighted, composed by a metastable arrangement of dry silt grains (possibly related to carbonate re-crystallisation) and a heterogeneously distributed clay fraction. The hydromechanical behaviour study includes the evaluation of the collapse sensibility of loess at stress states close to the in-situ one, by a series of suction-monitored oedometer tests performed at different constant strain rates (CSR tests). A maximum of collapse and a time-dependent behaviour of loess were observed. A triaxial testing programme at different water contents with suction measurement, allowed to obtain the yield surface of loess in a q/p diagram, and the water content and suction evolution upon loading and to confirm the suction hardening in this material

Mu Jun. / Thesis submitted in: December 2005. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 181-183). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Issues and Background --- p.5 / Chapter 2.1. --- Why Ecological Architecture? --- p.5 / Chapter 2.1.1. --- Fossil Fuels and Environmental Issues --- p.5 / Chapter 2.1.2. --- The Buildings' Role in the Issues --- p.9 / Chapter 2.2. --- Knowledge in Ecological Design --- p.11 / Chapter 2.2.1. --- About Ecological Architecture --- p.11 / Chapter 2.2.2. --- Thermal Study ~ A Significant Way to Ecological Architecture --- p.13 / Chapter 2.2.3. --- What is Suitable Ecological Architecture for Loess Plateau areas of China --- p.16 / Chapter 3. --- Defining the Future Ecological Architecture in Loess Plateau Areas --- p.20 / Chapter 3.1. --- Economy for Building --- p.20 / Chapter 3.1.1. --- Situation --- p.20 / Chapter 3.1.2. --- Technological Strategies towards a Cost-effective Ecological Approach --- p.22 / Chapter 3.1.3. --- Alternative-Technological Approach --- p.24 / Chapter 3.2. --- Climate --- p.25 / Chapter 3.2.1. --- Climatic Characteristics --- p.25 / Chapter 3.2.2. --- A climatically Responsive Approach ~ Selective Environmental Design --- p.32 / Chapter 3.2.3. --- Climatic Response of Thermal Design Guidelines --- p.33 / Chapter 3.2.3.1. --- Minimizing Heat loss through Building Fabrics --- p.34 / Chapter 3.2.3.2. --- Utilization of Available Natural Energy --- p.37 / Chapter 3.3. --- Benefits from Vernacular Architecture --- p.45 / Chapter 3.3.1. --- Earth ArchitecturéؤVernacular Architecture on Loess Plateau --- p.45 / Chapter 3.3.1.1. --- Classification --- p.46 / Chapter 3.3.1.2. --- Environmental Performance --- p.53 / Chapter 3.3.2. --- Literature Review of Studies on Earth Architecture --- p.58 / Chapter 3.3.2.1. --- Properties of Earth-based Materials --- p.58 / Chapter 3.3.2.2. --- Literature on Earth Architecture --- p.60 / Chapter 3.3.3. --- Issues and Development --- p.76 / Chapter 3.3.3.1. --- Limitation in Existing Earth Architecture of Loess Plateau --- p.76 / Chapter 3.3.3.2. --- Recent Research on Developing Earth Architecture in Loess Plateau Areas --- p.77 / Chapter 3.3.3.3. --- Considerations --- p.81 / Chapter 3.4. --- Conclusion --- p.82 / Chapter 4. --- Making of the Classroom as Designed for the Thermal Study --- p.84 / Chapter 4.1. --- Why a Classroom? --- p.84 / Chapter 4.2. --- The School Project and the Classroom Simulated --- p.85 / Chapter 5. --- Thermal Study by Simulating Experiments --- p.88 / Chapter 5.1. --- Research Methodology --- p.88 / Chapter 5.2. --- Program Validation --- p.89 / Chapter 5.3. --- Experimental Series of Simulation and Model Setup --- p.93 / Chapter 5.4. --- Thermal Mass and Insulation --- p.95 / Chapter 5.4.1. --- External Wall --- p.95 / Chapter 5.4.2. --- Roof Study --- p.97 / Chapter 5.4.3. --- "Windows, Doors and Glazing" --- p.100 / Chapter 5.4.4. --- Incorporated Performance --- p.103 / Chapter 5.5. --- Passive system for natural energy use --- p.106 / Chapter 5.5.1. --- Passive Solar System Study --- p.106 / Chapter 5.5.1.1. --- Wall-based Passive Solar System --- p.106 / Chapter 5.5.1.2. --- Roof-based Passive Solar System --- p.125 / Chapter 5.5.1.3. --- System Comparison in Thermal Performance --- p.135 / Chapter 5.5.2. --- Natural Ventilation System with the Heat Exchanger --- p.137 / Chapter 5.5.2.1. --- Pre-warming Effect of the Solar Space --- p.139 / Chapter 5.5.2.2. --- Effect of the Earth-air-tunnel --- p.142 / Chapter 5.5.2.3. --- Incorporation with the Chimney --- p.153 / Chapter 5.5.2.4. --- Comparison in Performance --- p.158 / Chapter 5.6. --- Summary --- p.159 / Chapter 6. --- Design Improvement and Performance Prediction --- p.162 / Chapter 6.1. --- System Incorporation and Design Improvement --- p.161 / Chapter 6.2. --- Thermal Performance Prediction --- p.167 / Chapter 7. --- Conclusion --- p.174 / Appendix --- p.179

Doctor of Philosophy / Department of Agronomy / Michel D. Ransom / Upland soils in east central Kansas have a complex genesis, often contain one or more paleosols, and form in multiple parent materials including loess, colluvium, residuum, and alluvium. Quaternary loess/paleosol investigations have largely ignored this region of Kansas, as the total loess thickness on uplands is <2 m thick. In this study, the objectives are to examine the morphology and genesis of the soils of interest and how these characteristics vary within soil profiles, across landscapes, and throughout the current series mapping extent. The series of interest include the Irwin, Konza, Dwight, and Ladysmith soil series. Methods used in this study include field descriptions and sampling, terrain analysis, micromorphological investigations, and laboratory characterization, including silt and clay mineralogy. Accelerator mass spectrometry (AMS) was used for numerical dating and determination of stable carbon isotope values (δ13C) for selected paleosols. Radiocarbon ages ranged from 24,000 to 19,000 yr BP and δ13C values were between -19 and -17 ‰ (PDB), indicating that the paleosols were formed in Gilman Canyon loess or the Severance formation, under a mix of C3 and C4 vegetation. Terrain analysis results illustrated that, in given drainage areas, the soil series were mapped on a wide range of slope positions. Field observations and terrain analysis confirmed no relationships between mollic epipedon thickness, solum thickness, paleosol thickness, or depth to the paleosol with respect to landform. Micromorphological investigations revealed increasing soil development with depth, i.e., the presence of two paleosols beneath the modern soil. Mean particle size and mineralogy vary geographically within individual series. Pedogenic carbonate accumulations and redoximorphic concentrations are common features of the soils of interest, and less common features include sodium and gypsum accumulations, slickensides, and redoximorphic depletions. Results from this study will be provided to the USDA-NRCS for use in future soil survey updates, and will contribute to Quaternary loess/paleosol knowledge in Kansas and the Great Plains.

Loess from west Greenland was studied to evaluate Holocene paleoclimate in the Arctic region. Deposits of loess are formed over long time scales through deposition of fine aeolian sediment and they exist in several places in the world. The main aeolian dust source in the study area is glaciofluvial material derived from the Greenland Ice Sheet (GrIS). Studying and understanding paleoclimate can help to make better predictions about the future in this sensitive region. Apart from sea level rise, melting of the GrIS also leads to an increase of aeolian dust as it gets released from the ice, which influences atmospheric and metrological phenomenon as well as the ice sheet’s albedo. This creates negative feedback mechanisms through increasing melting rates of glaciers and warming of the Arctic. Loess samples from two sites in the Kangerlussuaq area were analyzed and the mineral composition was measured with X-Ray Florescence Spectroscopy (XRF). With the measured mineral content, weathering indices were calculated to identify rates of weathering during the Holocene. Increased weathering intensities indicate warmer and more humid climate. The deposits in Greenland are relatively thin. Radiocarbon dating of the sediment suggests that the oldest parts of the profiles are about 4000 cal. yr B.P. (calibrated years before present). Arctic loess has not been studied very extensively. Weathering indices and ratios developed for classical loess, that had not been tested on Arctic loess, was used. The results were plotted by depth and age to visually identify changes over time. By considering the geology, climate and local conditions of the study area, some weathering indices seemed to be suitable, generating matching trends between the two sites. Compared with results from previous studies, the results also seemed credible. / Löss från västra Grönland studerades för att utvärdera holocent paleoklimat i Arktis. Lössjordar bildas över långa tidsskalor genom avsättning av fint vindburet sediment och de finns på flera platser i världen. Den huvudsakliga källan till det vindburna sedimentet i studieområdet är glaciofluvialt material härstammande från Grönlandsisen (GrIS). Att studera och förstå paleoklimat kan underlätta skapandet av bättre prognoser om framtiden i denna känsliga region. Bortsett från höjning av de globala havsnivåerna leder smältningen av GrIS också till en ökning av vindburet sediment då det frigörs från isen, vilket påverkar atmosfäriska och metrologiska fenomen samt isens albedo. Detta skapar negativa återkopplingsmekanismer genom ökande smälthastighet av glaciärer och uppvärmning av Arktis. Lössprover från två ställen i Kangerlussuaq-området analyserades och mineralsammansättningen mättes med röntgenstrålningsspektroskopi (XRF). Med det uppmätta mineralinnehållet beräknades vittringssindex för att identifiera vittringshastigheter under Holocen. Ökad vittringsintesitet indikerar varmare och fuktigare klimat. Avlagringarna på Grönland är relativt tunna. Kol-14-datering av sedimentet antyder att de äldsta delarna är cirka 4000 cal. yr B.P. (kalibrerade år före nutid). Arktisk löss är relativt ostuderad. Vittringsindex som har utvecklats för klassisk löss i tempererade regioner, och tidigare inte testats på arktisk löss, användes. Resultaten ritades i grafer efter djup och ålder för att visuellt identifiera förändringar över tid. Genom att ta hänsyn till geologin, klimatet och lokala förhållanden i studieområdet, verkade några av vittringsindexen ge trovärdiga resultat då matchande trender mellan bägge profiler kunde utläsas. I jämförelse med resultat från tidigare studier verkade resultaten också trovärdiga.

Loess is an unique record of the paleoclimate of the Quaternary. Because it is directly deposited from the atmosphere, it can be used as a proxy for wind speed and circulation patterns. It can also be directly dated using luminescence. The site of the loess being investigated for this paper is PrimelTrégastel (Brittany), which lies in north-western France of the shore to the English Channel. The English Channel may be one of the sources for loess of the last glaciation, the Wichselian, and is the reason for choosing Primel-Trégastel to investigate. It is the purpose of this paper to investigate the climate of the time the loess was formed at Primel-Trégastel using grain-size distribution analysis, as well as comparing its properties to other loess sites in north-western Europe. The results show that the loess of Primel-Trégastel is coarse and have a relatively high sand content. That may imply that the loess was deposited during cold and arid conditions by high wind speeds, and at that it may have had a relatively close source. The results also exhibit cycles in the coarseness of the grain-size, indicative of the climate varying between cold and relatively warmer, resulting in relatively higher and lower wind speeds respectively. The loess of Nantois and Pegwell Bay are also relatively coarse, and the loess of Pegwell Bay also have a high sand content. The loess of Nussloch was in comparison more unlike the one of Primel-Trégastel, possibly due to the lack of a local source of sand at Nussloch.

No description available.