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Articles 121 - 150 of 219

Full-Text Articles in Earth Sciences

Application Of A New Tree-Ring Based Drought Reconstruction Method At Multiple Forest Sites Across Indiana, U.S.A., Kayla Mechelle Pendergrass Aug 2015

Application Of A New Tree-Ring Based Drought Reconstruction Method At Multiple Forest Sites Across Indiana, U.S.A., Kayla Mechelle Pendergrass

Master's Theses

This thesis research used techniques of dendrochronology to investigate the efficacy of using multiple co-occurring species (MCOS) in a climate reconstruction model compared to a single species (SS) in four old-growth forests in Indiana: Pioneer Mothers Memorial Forest (PM), Donaldson Woods (DW), Hoot Woods (HW), and Lilly Dickey Woods (LD). The objectives of this study were to [1] evaluate the climate response of all chronologies (n = 19; 7 species) to determine the most appropriate climate variable for reconstruction and [2] determine if the MCOS model outperforms the SS model at each individual study site. Model comparison was conducted …


Slides: Gwc Review Report, Larry Macdonnell Jun 2015

Slides: Gwc Review Report, Larry Macdonnell

Innovations in Managing Western Water: New Approaches for Balancing Environmental, Social and Economic Outcomes (Martz Summer Conference, June 11-12)

Presenter: Larry MacDonnell, University of Colorado Law School

12 slides


Using Declassified Satellite Imagery To Quantify Geomorphic Change: A New Approach And Application To Himalayan Glaciers, Joshua Michael Maurer Jun 2015

Using Declassified Satellite Imagery To Quantify Geomorphic Change: A New Approach And Application To Himalayan Glaciers, Joshua Michael Maurer

Theses and Dissertations

Himalayan glaciers are key components of earth's cryosphere, acting as hydrological reservoirs vital to many human and natural systems. Most Himalayan glaciers are shrinking in response to changing climate, which will potentially impact water resources, natural hazards, sea level rise, and many other aspects. However, there is much uncertainty regarding the state of these glaciers, as direct field data are difficult to obtain. Accordingly, long-timespan remote sensing techniques are needed to measure changing glaciers, which have memory and often respond to climate on decadal timescales. This study uses declassified historical imagery from the Hexagon spy satellite database to fulfill this …


Eocene-Oligocene Latitudinal Climate Gradients In North America Inferred From Stable Isotope Ratios In Perissodactyl Tooth Enamel, Alessandro Zanazzi, Emily Judd, Andrew Fletcher, Harold Bryant, Matthew J. Kohn Oct 2014

Eocene-Oligocene Latitudinal Climate Gradients In North America Inferred From Stable Isotope Ratios In Perissodactyl Tooth Enamel, Alessandro Zanazzi, Emily Judd, Andrew Fletcher, Harold Bryant, Matthew J. Kohn

Geosciences Faculty Publications and Presentations

The Eocene-Oligocene transition (~ 34 Ma) was one of the most pronounced episodes of climate change of the Cenozoic. In order to investigate this episode of global climate cooling in North America, we analyzed the carbon and oxygen stable isotope composition of the carbonate component of 19 perissodactyl (horse and rhino) tooth enamel samples from the Eocene-Oligocene rocks of the Cypress Hills Formation (southwestern Saskatchewan, Canada); we then compared the results with previously published data from the US Great Plains (Nebraska, South Dakota, and Wyoming).

Average (± 1σ) perissodactyl enamel δ13C values (vs. V-PDB) in the Eocene (-8.8 …


Discovery Of Shallow-Marine Biofacies Conodonts In A Bioherm Within The Carboniferous-Permian Transition In The Omalon Massif, Ne Russia Near The North Paleo-Pole: Correlation With A Warming Spike In The Southern Hemisphere, Vladimir I. Davydov, Alexander S. Biakov Aug 2014

Discovery Of Shallow-Marine Biofacies Conodonts In A Bioherm Within The Carboniferous-Permian Transition In The Omalon Massif, Ne Russia Near The North Paleo-Pole: Correlation With A Warming Spike In The Southern Hemisphere, Vladimir I. Davydov, Alexander S. Biakov

Geosciences Faculty Publications and Presentations

The conodont genera Hindeodus and Streptognathodus are reported for the first time within the Carboniferous-Permian transition in the northern high latitudes of the Paren’ River, Omolon Massif, NE Russia. Several fossil groups, including brachiopods, bivalves, scaphopods and microgastropods were found to be prolific in the invertebrate-dominated bioherms. These bioherms occur within predominantly siliciclastic sequences with extremely poor fauna, whereas in the studied bioherms the diversity of the bivalves and brachiopods exceeded observed diversity elsewhere in coeval facies in NE Russia. The bioherms are biostratigraphically constrained as uppermost Pennsylvanian to lowermost Cisuralian based on ammonoids. The very unusual peak of bivalve …


Climate Change In Southern New Hampshire: Past, Present And Future, Cameron P. Wake, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, C. Keeley, Julie Labranche Apr 2014

Climate Change In Southern New Hampshire: Past, Present And Future, Cameron P. Wake, Elizabeth A. Burakowski, Peter Wilkinson, Katharine Hayhoe, Anne Stoner, C. Keeley, Julie Labranche

The Sustainability Institute Publications

EARTH’S CLIMATE CHANGES. It always has and always will. However, an extensive and growing body of scientific evidence indicates that human activities—including the burning of fossil fuel (coal, oil, and natural gas) for energy, clearing of forested lands for agriculture, and raising livestock—are now the primary force driving change in the Earth’s climate system. This report describes how the climate of southern New Hampshire has changed over the past century and how the future climate of the region will be affected by a warmer planet due to human activities.


Peritidal Carbonate Cycles Induced By Carbonate Productivity Variations: A Conceptual Model For An Isolated Early Triassic Greenhouse Platform In South China, Wan Yang, Daniel J. Lehrmann Apr 2014

Peritidal Carbonate Cycles Induced By Carbonate Productivity Variations: A Conceptual Model For An Isolated Early Triassic Greenhouse Platform In South China, Wan Yang, Daniel J. Lehrmann

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Eustasy has commonly been invoked to explain peritidal carbonate cyclicity, but is difficult to explain cycles formed in a greenhouse climate when eustasy is minimal. We propose that peritidal cycles on an Early Triassic isolated carbonate platform in Guizhou, South China, were formed by hierarchical carbonate productivity variations. Most of the 149 shallowing-upward cycles are typically terminated by flooding over intertidal facies and contain rare supratidal facies and no prolonged subaerial exposure. Low-diversity benthos in the platform interior during the post-end-Permian biotic recovery were sensitive to environmental perturbations, which caused variations in benthic sediment productivity in the subtidal carbonate factory. …


Groundwater Flow Across Spatial Scales: Importance For Climate Modeling, Nir Krakauer, Haibin Li, Ying Fan Mar 2014

Groundwater Flow Across Spatial Scales: Importance For Climate Modeling, Nir Krakauer, Haibin Li, Ying Fan

Publications and Research

Current regional and global climate models generally do not represent groundwater flow between grid cells as a component of the water budget. We estimate the magnitude of between cell groundwater flow as a function of grid cell size by aggregating results from a numerical model of equilibrium groundwater flow run and validated globally. We find that over a broad range of cell sizes spanning that of state of the art regional and global climate models, mean between cell groundwater flow magnitudes scale with the reciprocal of grid cell length. We also derive this scaling a priori from a simple statistical …


Kenyan Climate Variation Assessment Through Rainfall Anomalies And Sea Surface Temperature (Sst) Correlations, Kimberly E. Lykens Jan 2014

Kenyan Climate Variation Assessment Through Rainfall Anomalies And Sea Surface Temperature (Sst) Correlations, Kimberly E. Lykens

STAR Program Research Presentations

The diverse and varied climate of Eastern Africa’s Kenya is home to an agriculturally dependent populace, in which farmers and other related economic sectors make up the majority of livelihoods and gross domestic product. Recurring droughts and severe flooding are major concerns for local farmers and governmental entities. The purpose of this study is to identify and categorize differences in rainfall trends over Kenya and to examine relationships between seasonal rainfall anomalies of sea surface temperature (SST), with an ultimate goal to improve predictions of wet season rainfall amounts. The analysis began with data from 27 national and cooperative weather …


Changes In Climate And Moisture Availability In The Antarctic Eocene, Oligocene, And Miocene: Evidence From Palynological And Stable Isotope Geochemical Analyses Of The Shaldril And Andrill Cores, Kathryn Whitney Griener Jan 2014

Changes In Climate And Moisture Availability In The Antarctic Eocene, Oligocene, And Miocene: Evidence From Palynological And Stable Isotope Geochemical Analyses Of The Shaldril And Andrill Cores, Kathryn Whitney Griener

LSU Doctoral Dissertations

Prior to the Late Eocene, the Antarctic continent experienced lush vegetation under temperate conditions. Just before the Eocene/Oligocene Boundary, the climate of the southernmost continent began to deteriorate dramatically. This cooling trend largely continued until most Antarctic vegetation disappeared, ~13.85-12.8 Ma. Classifying the nature and cause of Antarctica’s drastic climate change is essential for furthering our knowledge of Earth’s history, and also for grasping the potential effects of current and future climate shifts. Here, I present evidence from three new palynomorph-centric studies that deepen our understanding of Antarctic earth science, climate change, and of climate proxies. The first study involved …


The Evaluation Of Water Storage In Death Valley Using Grace Satellite Data, Maile Sweigart May 2013

The Evaluation Of Water Storage In Death Valley Using Grace Satellite Data, Maile Sweigart

UNLV Theses, Dissertations, Professional Papers, and Capstones

As drought conditions spread across the United States, concerns over water supplies, water use, and water management policies are growing and possible contributing environmental factors are continually being scrutinized. This thesis examines Death Valley as an analog for Southern Nevada and utilizes NASA EOS data, combined with ancillary climate data, to assess the effect of decadal climate variability on groundwater storage in the Death Valley area. Historical climate data, combined with satellite imagery observations, were compiled and calculated for analyses. Conclusions derived from statistical analyses infer trends between GRACE (Gravity Recovery and Climate Experiment) satellite data and fluctuating levels of …


A Latest Carboniferous Warming Spike Recorded By A Fusulinid-Rich Bioherm In Timor Leste: Implications For East Gondwana Deglaciation, Vladimir I. Davydov, David W. Haig, Eujay Mccartain Apr 2013

A Latest Carboniferous Warming Spike Recorded By A Fusulinid-Rich Bioherm In Timor Leste: Implications For East Gondwana Deglaciation, Vladimir I. Davydov, David W. Haig, Eujay Mccartain

Geosciences Faculty Publications and Presentations

During the late Paleozoic and early Mesozoic Timor lay in the northern part of the north–south East Gondwana rift system along which the western margin of Australia later developed. Discovery of a latest Gzhelian bioherm in the central highlands of Timor Leste has implications for latest Carboniferous–earliest Permian climate history and deglaciation in basins further south in the rift system.

Limestone outcrop of the Maubisse Formation near the village of Kulau is recognized as a bioherm with a massive lower unit, including reef framework at the base, and a bedded grainstone upper unit. The bioherm developed on a basalt substrate …


Development And Evaluation Of An Inquiry-Based Unit For Teaching About Paleoclimate And Climate Change, Steven Barone Apr 2013

Development And Evaluation Of An Inquiry-Based Unit For Teaching About Paleoclimate And Climate Change, Steven Barone

Masters Theses

The purpose of this action research study is to develop and evaluate a sequence of four lessons for an introductory earth science course taken by future elementary teachers. Action research is a reflective process of data collection and analysis used by teachers to improve their classroom practice. This study’s goal is to produce a series of lessons that align with the course philosophy of student-driven learning through guided-inquiry and are effective at improving students’ understanding of climate change.

Three data sets were used to evaluate the lessons: 1) student knowledge gains on an objective pre- and post-test, 2) students’ self-reported …


On The Lack Of Stratospheric Dynamical Variability In Low‐Top Versions Of The Cmip5 Models, Andrew J. Charlton-Perez, Mark P. Baldwin, Thomas Birner, Robert X. Black, Amy H. Butler, Natalia Calvo, Nicholas A. Davis, Edwin P. Gerber, Nathan Gillett, Steven Hardiman, Junsu Kim, Kirsten Krüger, Yun-Young Lee, Elisa Manzini, Brent A. Mcdaniel, Lorenzo Polvani, Thomas Reichler, Tiffany A. Shaw, Michael Sigmond, Seok-Woo Son, Matthew Toohey, Laura Wilcox, Shigeo Yoden, Bo Christiansen, François Lott, Drew Shindell, Seiji Yukimoto, Shingo Watanabe Mar 2013

On The Lack Of Stratospheric Dynamical Variability In Low‐Top Versions Of The Cmip5 Models, Andrew J. Charlton-Perez, Mark P. Baldwin, Thomas Birner, Robert X. Black, Amy H. Butler, Natalia Calvo, Nicholas A. Davis, Edwin P. Gerber, Nathan Gillett, Steven Hardiman, Junsu Kim, Kirsten Krüger, Yun-Young Lee, Elisa Manzini, Brent A. Mcdaniel, Lorenzo Polvani, Thomas Reichler, Tiffany A. Shaw, Michael Sigmond, Seok-Woo Son, Matthew Toohey, Laura Wilcox, Shigeo Yoden, Bo Christiansen, François Lott, Drew Shindell, Seiji Yukimoto, Shingo Watanabe

Faculty Articles

We describe the main differences in simulations of stratospheric climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine stratospheric vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean stratospheric climate by the two model ensembles is similar, the low-top model ensemble has very weak stratospheric variability on daily and interannual time scales. The frequency of major sudden stratospheric warming events is strongly underestimated by the low-top models with less than half the frequency of events …


Controlling Factors On Bedrock River Sinuosity In The Eastern Tibetan Plateau, Lydia Curliss Jan 2013

Controlling Factors On Bedrock River Sinuosity In The Eastern Tibetan Plateau, Lydia Curliss

Honors Papers

Average sinuosity of bedrock rivers across the eastern Tibetan Plateau (including the Yangtze, Mekong, Salween, Irrawaddy, and Tsang Po) ranges from 1.20-1.41. From 25°-30°N, sinuosity marginally increases east to west; over the entire distance of each river, sinuosity increases north to south. Increases in sinuosity parallel a regional tectonic gradient in an area with a marginal climate gradient. Several past studies correlate sinuous bedrock rivers in mountainous regions with gradients in climate, arguing that landslides are the main mechanism by which bedrock rivers increase sinuosity. Other studies find correlations between tectonics and increasing landslide frequency. To investigate the role of …


The Roles Of Humans And Climatic Variation On The Fire History Of Subalpine Meadows - Mount Rainer National Park (Washington), Michael Louis Lukens Jan 2013

The Roles Of Humans And Climatic Variation On The Fire History Of Subalpine Meadows - Mount Rainer National Park (Washington), Michael Louis Lukens

All Master's Theses

With the creation of Mount Rainier National Park (MORA) in 1899 came the active management of the park's landscapes and a heavy emphasis on fire suppression. Today managers at MORA have made returning fire to the park's landscapes a top priority. In order to achieve this goal, and to make more informed decisions in regard to the application of fire, land managers at MORA need to better understand past fire occurrences and the drivers of fire activity on the mountain. To address this problem, analysis of macroscopic charcoal preserved in lake sediments was used to reconstruct the fire history for …


Modeling Glacial Termination, Michael Murphy Jun 2012

Modeling Glacial Termination, Michael Murphy

Natural Resources Management and Environmental Sciences

Examines possible cause of the glacial termination or ice age cycle using a numerical model created by Tziperman et al. Also explores possible physical mechanisms causing the observed cycle of slow cooling followed by rapid warming.


Tracking Lateglacial And Early Holocene Environmental Change: A Palaeolimnological Study Of Sediment At Preluca Tiganului, Nw Romania, Angelica Feurdean Mar 2012

Tracking Lateglacial And Early Holocene Environmental Change: A Palaeolimnological Study Of Sediment At Preluca Tiganului, Nw Romania, Angelica Feurdean

Studia UBB Geologia

Palaeoecological, palaeohydrological, and paleoenvironmental reconstruction of the Late Glacial and the early Holocene have been performed from sediment accumulated in a small former crater lake, in the GutâI Mountains, NW Romania. Pollen, lithology, mineral magnetic, and loss-on-ignition analyses in conjunction to radiocarbon dating have been use for this purpose. The data indicates that during the Late Glacial period, vegetation dynamics were likely driven by climatic fluctuations. The climate events during the Late Glacial are well mirrored in local vegetation assemblage development, and past lake level fluctuations. These climatic events recorded in south-eastern Europe, are well correlated with the climate events …


Late Miocene Palaeoclimate And Ecosystem Dynamics In Southwestern Bulgaria − A Study Based On Pollen Data From The Gotse-Delchev Basin, Dimiter A. Ivanov, Torsten Utescher, A. Rahman Ashraf, Volker Mosbrugger, Vladimir Bozukov, Nadezhda Djorgova, Evgenia Slavomirova Jan 2012

Late Miocene Palaeoclimate And Ecosystem Dynamics In Southwestern Bulgaria − A Study Based On Pollen Data From The Gotse-Delchev Basin, Dimiter A. Ivanov, Torsten Utescher, A. Rahman Ashraf, Volker Mosbrugger, Vladimir Bozukov, Nadezhda Djorgova, Evgenia Slavomirova

Turkish Journal of Earth Sciences

A profile 63 m thick in the Late Miocene in the Gotse-Dechev Basin (SW Bulgaria) was sampled for pollen analysis in the Kanina opencast mine. The exposed sequence comprises a basal unit with brown coal-clay cycles and clayey/siliciclastic cover layers partly representing a lacustrine facies. A total of 60 pollen samples were analysed, but quantitative data are confined to 30 polleniferous samples. The palynological analysis carried out provides data about the composition and structure of the fossil vegetation. The main vegetation type was a mixed mesophytic forest dominated by Carya, Fagus, Betula, Quercus, and Ulmus. Accessory elements included Magnolia, Corylopsis, …


Changing Land Use On Unproductive Soils, Andrew Blake, Mike Clarke, Angela Stuart-Street Jan 2012

Changing Land Use On Unproductive Soils, Andrew Blake, Mike Clarke, Angela Stuart-Street

Resource management technical reports

A three year study completed in 2010 examined farming systems in the north-eastern agricultural region and eastern wheatbelt of Western Australia which experienced a succession of variable seasons from 2000. This culminated in severe drought in 2006 and 2007. At that time, farmers experienced labour shortages and declining terms of trade triggered by cost inflation outpacing growth in commodity prices. As a result, farm business equity was eroded as farm debt escalated. This left many farm businesses in a highly vulnerable state. At the time of the study many farmers were facing an uncertain future.

These experiences, coupled with a …


Cora – A Dedicated Device For Carbon Dioxide Monitoring In Cave Environments, Marc Luetscher, Felix Ziegler Jan 2012

Cora – A Dedicated Device For Carbon Dioxide Monitoring In Cave Environments, Marc Luetscher, Felix Ziegler

International Journal of Speleology

High resolution time-series of cave CO2 fluctuations are increasingly demanded to quantify calcite precipitation processes. CORA, an energy-efficient NDIR-device, has been specifically developed for the long-term monitoring of carbon dioxide in remote cave environments. To allow comparison between different cave sites, changes in air pressure and temperature are compensated for using dedicated probes. Laboratory experiments demonstrate that CORA’s precision is adapted to the analysis of spatially and temporally variable CO2 regimes and therefore suitable for a large number of applications. Data obtained with 12 independently calibrated instruments are reproducible within 3% (1σ). The two-point calibration function is validated …


Atlantic Multidecadal Oscillation-Forced Regional Summertime Precipitation Variations In The Central United States, Michael C. Veres Dec 2011

Atlantic Multidecadal Oscillation-Forced Regional Summertime Precipitation Variations In The Central United States, Michael C. Veres

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The purpose of this research is to identify the regional mechanisms by which the Atlantic Multidecadal Oscillation (AMO) influences summer (June-August) precipitation in the central U.S. This was accomplished by running two different sets of simulations using the Weather Research and Forecasting (WRF) regional climate model, one forced by observations and the other forced only by variations in the AMO as obtained via a global climate model (GCM). The results reveal a complex set of mechanisms active in the lower and middle troposphere by which the AMO influences summer circulation and precipitation in the central U.S. During the cold phase …


The Use Of Large-Scale Climate Data To Predict Drought, River Flows, And Vegetation Over Central-Southwest Asia, Matthew Barlow Jun 2011

The Use Of Large-Scale Climate Data To Predict Drought, River Flows, And Vegetation Over Central-Southwest Asia, Matthew Barlow

2011 Symposium on Data-Driven Approaches to Droughts

Central-Southwest Asia is a semi-arid, economically stressed region where droughts have severe societal impacts in terms of agriculture, farming, access to fresh water for drinking, and sanitation. There are two sources of drought predictability for this area: the influence of predictable modes of large-scale climate variability at both seasonal and intraseasonal timescales, and the importance of the snow pack to warm season river flows and vegetation. Local data scarcity is a critical problem for the region, both for historical analysis and for real-time monitoring. However, analysis shows that satellite data can be used to provide a considerable amount of high-resolution …


Monitoring Drought Across Many Scales, Chris Funk Jun 2011

Monitoring Drought Across Many Scales, Chris Funk

2011 Symposium on Data-Driven Approaches to Droughts

Monitoring drought across many scales Chris Funk As gas and food prices increase while per capita harvested area decreases, drought and disruptions in food availability exert more and more pressure on the political and economic stability of ‘frailed’ states. Improved drought monitoring across many spatial and temporal time scales has therefore become increasingly important. As this need mounts, so have our capacities to observe and understand the earth’s climate. Relatively new satellite systems, such as the Moderate Resolution Imaging Spectrometer, allow us to watch the earth at scales of ~100 meters. Improved rainfall retrievals give us more timely and accurate …


Slides: Who Should Be At The Table, And What Should They Be Talking About?, Robert W. Adler Jun 2011

Slides: Who Should Be At The Table, And What Should They Be Talking About?, Robert W. Adler

Navigating the Future of the Colorado River (Martz Summer Conference, June 8-10)

Presenter: Robert W. Adler, James I. Farr Chair in Law, University of Utah, S.J. Quinney College of Law

9 slides


Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail Feb 2011

Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail

Crop Updates

This session covers twelve papers from different authors:

1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima

Department of Agriculture and Food

2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food

3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food

4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food

5. Land constraints limiting wheat yields in …


Farmer Perceptions Of Sustainable Agriculture Practices And Drought Risk Reduction In Nebraska, Usa, Cody L. Knutson, Tonya Haigh, Michael J. Hayes, Melissa Widhalm, J. Nothwehr, M. Kleinschmidt, L. Graf Jan 2011

Farmer Perceptions Of Sustainable Agriculture Practices And Drought Risk Reduction In Nebraska, Usa, Cody L. Knutson, Tonya Haigh, Michael J. Hayes, Melissa Widhalm, J. Nothwehr, M. Kleinschmidt, L. Graf

National Drought Mitigation Center: Faculty Publications

Social factors, such as farming methods, have an impact on farm vulnerability to drought, but have received little research or policy attention. Some researchers and advocates have argued that sustainable agriculture systems are less vulnerable to climate risk than conventional systems because sustainable agriculture requires producers to have skills promoting adaptability. In this paper, we investigate producers’ perceptions on the use of sustainable agriculture in reducing drought risk, and what they believe would help them better adapt to drought. We surveyed and interviewed farmer members of two sustainable agriculture organizations in Nebraska, USA, during a multi-year drought period from 1999 …


Assessment Of Black Carbon In Snow And Ice From The Tibetan Plateau And Pacific Northwest, Matthew Glen Jenkins Jan 2011

Assessment Of Black Carbon In Snow And Ice From The Tibetan Plateau And Pacific Northwest, Matthew Glen Jenkins

All Master's Theses

An ice core from Mt. Geladandong, Tibetan Plateau, spanning 1853-1983, and snow samples collected over two winters from the Cascade Mountains were analyzed for concentrations of black carbon (BC) using a Single Particle Soot Photometer (SP2). From the ice core, the high-resolution BC record displayed substantial variability, a 2-fold increase in peak concentrations from 1853-1930 to 1930-1983, and a 1.6-fold increase in average concentrations from 1853-1975 to 1975-1983. Concentrations were also higher than at two areas closer to BC sources and analyzed by the same method. In the Pacific Northwest, BC concentrations varied seasonally and annually, with the highest concentrations …


An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land–Ocean Boundary, Angela C. Bliss Aug 2010

An Intercomparison Of Regional Atmospheric Circulation And The Melt Season Loss Of Arctic Snow Cover And Sea Ice Extent Across The Land–Ocean Boundary, Angela C. Bliss

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

This study is designed to compare the monthly continental snow cover and sea ice extent loss in the Arctic with regional atmospheric conditions including: mean sea level pressure, 925 hPa air temperature, and mean wind direction among others during the melt season (March-August) over the 29-year study period 1979-2007. Little research has gone into studying the concurrent variations in the annual loss of continental snow cover and sea ice extent across the land-ocean boundary, since these data are largely stored in incompatible formats. However, the analysis of these data, averaged spatially over three autonomous study regions located in Siberia, North …


Sediment Flux Through The Rio Grande River: A Monsoonal Effect, Troy C. Hiatt Jun 2010

Sediment Flux Through The Rio Grande River: A Monsoonal Effect, Troy C. Hiatt

Theses and Dissertations

Climate has historically been recognized as an influence on sediment flux and deposition. The North American Monsoon is suggested as the forcing mechanism of deltaic progradational events of the Rio Grande River delta. Interpretations of reflection seismic profiles reveal that eustatic rise in sea-level from the Last Glacial Maximum to present is accompanied by several regressional events of the Rio Grande delta 5.5, 9.5, and 11.5 ka BP. Much of the migration of depositional facies within a delta system is forced by hinterland tectonics and base-level rise and fall. However, we suggest that the movement of facies within the Rio …