Open Access. Powered by Scholars. Published by Universities.®

Other Earth Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 391 - 420 of 1654

Full-Text Articles in Other Earth Sciences

Detrital Zircon Geochronology Of Paleoproterozoic Sedimentary Rocks From The Upper Huronian Supergroup, Canada, Carolyn M. Hill, Don W. Davis, Patricia L. Corcoran Jun 2019

Detrital Zircon Geochronology Of Paleoproterozoic Sedimentary Rocks From The Upper Huronian Supergroup, Canada, Carolyn M. Hill, Don W. Davis, Patricia L. Corcoran

Western Research Forum

The Huronian Supergroup is a well-known succession of primarily sedimentary rocks exposed north of Lake Huron. Deposition of the succession is constrained between 2450 and 2220 Ma (million years), which corresponds with Earth’s rise of atmospheric oxygen, however the depositional timing of the uppermost formations cannot be refined further due to a lack of interbedded volcanic rocks. A geochronological study of detrital zircon grains from sandstone and claystone beds from the two youngest Huronian formations, the Gordon Lake and Bar River formations, was completed in order to confine the maximum age of deposition.

Zircon is a mineral that commonly forms …


The Antiquity Of The Sahara Desert: New Evidence From The Mineralogy And Geochemistry Of Pliocene Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Juan F. Betancort, Alejandro Lomoschitz Jun 2019

The Antiquity Of The Sahara Desert: New Evidence From The Mineralogy And Geochemistry Of Pliocene Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Juan F. Betancort, Alejandro Lomoschitz

United States Geological Survey: Staff Publications

The Sahara is the largest warm desert in the world, but its age has been controversial, with estimates ranging from Miocene to Holocene. Mineralogical and geochemical data show that paleosols of Pliocene to mid- Pleistocene age on Fuerteventura and Gran Canaria in the Canary Islands have developed in part from inputs of dust from Africa. These paleosols contain quartz and mica, minerals that are abundant in African dust but are rare in the basaltic rocks that dominate the Canary Islands. Trace elements with minimal mobility, Sc, Cr, Hf, Th, and Ta as well as the rare earth elements, show that …


Morphological And Mineralogical Evidence For Ancient Bat Presence In Cova Des Pas De Vallgornera (Llucmajor, Mallorca, Western Mediterranean), Antoni Merino, Joan J. Fornós, Antoni Mulet, Joaquín Ginés May 2019

Morphological And Mineralogical Evidence For Ancient Bat Presence In Cova Des Pas De Vallgornera (Llucmajor, Mallorca, Western Mediterranean), Antoni Merino, Joan J. Fornós, Antoni Mulet, Joaquín Ginés

International Journal of Speleology

Cova des Pas de Vallgornera is a unique karst cave located at the Llucmajor coastal platform that stands out not only because of its length, more than 78 km, but also for its particular morphological suite, richness and variety of speleothems and mineral infillings. Although the mineralogy of speleothems and minerals related to hypogene morphologies has been studied and described, the existence of minerals derived from guano deposits was still poorly investigated. The cave hosted bat colonies until the collapse of its natural entrances, circa 2.4 My ago, since then until its discovery in 1968, the cave remained sealed. These …


Machine Learning Vs Conventional Analysis Techniques For The Earth’S Magnetic Field Study, Sheri Loftin, Sarah J. Fite, Laura V. Bishop, Stavros Kotsiaros May 2019

Machine Learning Vs Conventional Analysis Techniques For The Earth’S Magnetic Field Study, Sheri Loftin, Sarah J. Fite, Laura V. Bishop, Stavros Kotsiaros

SMU Data Science Review

Abstract. Current techniques for calculating and generating models used for analyzing the Earth’s magnetic field are laborious and time-consuming. We assert that machine learning can have a significant impact on building magnetic field models more quickly and on various levels of complexity, specifically as it pertains to data cleansing and sorting. Our approach to this problem uses a reverse iterative multi-phase process for data cleansing, in which, initially, the CHAOS-6 model data is examined to determine if machine learning can be used to differentiate between useful data components for spherical harmonics, versus data noise. During this phase, six different machine …


Remote Sensing Time-Series Analysis, Machine Learning, And K-Means Clustering Improves Dryland Vegetation And Biological Soil Crust Classification, Joshua Enterkine May 2019

Remote Sensing Time-Series Analysis, Machine Learning, And K-Means Clustering Improves Dryland Vegetation And Biological Soil Crust Classification, Joshua Enterkine

Boise State University Theses and Dissertations

Dryland and semi-arid vegetation communities, although appearing to the casual observer as relatively simplistic and homogeneous, are in fact the opposite. Upon further inspection, semi-arid vegetation is highly complex and heterogeneous at almost any scale. The same holds true for biological soil crust. Growing concern about global changes in climate, nutrient cycles, and land use have required increasing scrutiny of our understanding of these communities and all of their constituents, as we seek to improve forecasting models and inform land management decisions. This thesis aims to provide insight to the paradigm of how we create and interpret vegetation classifications in …


Tropospheric And Ionospheric Anomalies Induced By Volcanic And Saharan Dust Events As Part Of Geosphere Interaction Phenomena, Valerio Tramutoli, Francesco Marchese, Alfredo Falconieri, Carolina Filizzola, Nicola Genzano, Katsumi Hattori, Mariano Lisi, Jann-Yenq Liu, Dimitar Ouzounov, Michel Parrot, Nicola Pergola, Sergey Pulinets Apr 2019

Tropospheric And Ionospheric Anomalies Induced By Volcanic And Saharan Dust Events As Part Of Geosphere Interaction Phenomena, Valerio Tramutoli, Francesco Marchese, Alfredo Falconieri, Carolina Filizzola, Nicola Genzano, Katsumi Hattori, Mariano Lisi, Jann-Yenq Liu, Dimitar Ouzounov, Michel Parrot, Nicola Pergola, Sergey Pulinets

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this work, we assessed the possible relation of ionospheric perturbations observed by Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER), Global Positioning System total electron content (GPS TEC), National Oceanic and Atmospheric Administration (NOAA)-derived outgoing longwave-Earth radiation (OLR), and atmospheric chemical potential (ACP) measurements, with volcanic and Saharan dust events identified by ground and satellite-based medium infrared/thermal infrared (MIR/TIR) observations. The results indicated that the Mt. Etna (Italy) volcanic activity of 2006 was probably responsible for the ionospheric perturbations revealed by DEMETER on 4 November and 6 December and by GPS TEC observations on 4 November and 12 …


Growth, Condition, And Trophic Relations Of Stocked Trout In Southern Appalachian Mountain Streams, Jesse R. Fischer, Thomas J. Kwak, H. Jared Flowers, W. Gregory Cope, Jacob M. Rash, Douglas A. Besler Apr 2019

Growth, Condition, And Trophic Relations Of Stocked Trout In Southern Appalachian Mountain Streams, Jesse R. Fischer, Thomas J. Kwak, H. Jared Flowers, W. Gregory Cope, Jacob M. Rash, Douglas A. Besler

United States Geological Survey: Staff Publications

Stream trout fisheries are among the most popular and valuable in the United States, but many are dependent on hatcheries to sustain fishing and harvest. Thus, understanding the ecology of hatchery‐reared trout stocked in natural environments is fundamental to management. We evaluated the growth, condition, and trophic relations of Brook Trout Salvelinus fontinalis, Brown Trout Salmo trutta, and Rainbow Trout Oncorhynchus mykiss that were stocked in southern Appalachian Mountain streams in western North Carolina. Stocked and wild (naturalized) trout were sampled over time (monthly; September 2012–June 2013) to compare condition and diet composition and to evaluate temporal dynamics of trophic …


Notes And Discussion Piece: Status Of The Topeka Shiner In Iowa, Clay L. Pierce, Nicholas T. Simpson, Alexander P. Bybel, Courtney L. Zambory, Michael J. Weber, Kevin J. Roe Apr 2019

Notes And Discussion Piece: Status Of The Topeka Shiner In Iowa, Clay L. Pierce, Nicholas T. Simpson, Alexander P. Bybel, Courtney L. Zambory, Michael J. Weber, Kevin J. Roe

United States Geological Survey: Staff Publications

The Topeka shiner Notropis topeka is native to Iowa, Kansas, Minnesota, Missouri, Nebraska, and South Dakota and has been federally listed as endangered since 1998. Our goals were to determine the present distribution and qualitative status of Topeka shiners throughout its current range in Iowa and characterize the extent of decline in relation to its historic distribution. We compared the current (2016–2017) distribution to distributions portrayed in three earlier time periods. In 2016–2017 Topeka shiners were found in 12 of 20 HUC10 watersheds where they occurred historically. Their status was classified as stable in 21% of the HUC10 watersheds, possibly …


Establishing Relationships Between Drought Indices And Wildfire Danger Outputs: A Test Case For The California-Nevada Drought Early Warning System, Daniel J. Mcevoy, Mike Hobbins, Timothy J. Brown, Kristin Vander Molen, Tamara Wall, Justin L. Huntington, Mark D. Svoboda Apr 2019

Establishing Relationships Between Drought Indices And Wildfire Danger Outputs: A Test Case For The California-Nevada Drought Early Warning System, Daniel J. Mcevoy, Mike Hobbins, Timothy J. Brown, Kristin Vander Molen, Tamara Wall, Justin L. Huntington, Mark D. Svoboda

National Drought Mitigation Center: Faculty Publications

Relationships between drought indices and fire danger outputs are examined to (1) incorporate fire risk information into the National Integrated Drought Information System California–Nevada Drought EarlyWarning System and (2) provide a baseline analysis for application of drought indices into a fire risk management framework. We analyzed four drought indices that incorporate precipitation and evaporative demand (E0) and three fire indices that reflect fuel moisture and potential fire intensity. Seasonally averaged fire danger outputs were most strongly correlated to multi-scalar drought indices that use E0 (the Evaporative Demand Drought Index (EDDI) and the Standardized Precipitation Evapotranspiration Index (SPEI)) at approximately annual …


Droughtscape, Spring 2019, Cory Matteson Apr 2019

Droughtscape, Spring 2019, Cory Matteson

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

From the Director

Wet and cool conditions bring drought relief to the West

Notable numbers from Q1

Drought impact summary, 1st quarter 2019

New research examines drought effects on state recreation areas

At Ethiopian space science workshop, NDMC climatologist sees promise in preparing for drought

U.S.- affiliated Pacific Islands now part of U.S. Drought Monitor

Water conservation tips for drought, flood and other disasters

Upcoming events


Estimating Coastal Water Turbidity Using Viirs Nighttime Measurement, Chih-Wei Huang Mar 2019

Estimating Coastal Water Turbidity Using Viirs Nighttime Measurement, Chih-Wei Huang

USF Tampa Graduate Theses and Dissertations

Coastal water turbidity is a key environmental factor that influences the relative clarity of the water, which therefore reduces sunlight penetration. The comprehensive spatial and temporal coverage of remote sensing allows mapping of water turbidity near the coast. Even in locations where time-consuming and expensive conventional turbidity monitoring programs exist, local technological limitations prevent complete coverage. Traditional optical satellite techniques using the visible band also have limitations in monitoring turbidity due to non-optimal observing conditions such as clouds, sun-glint, and thick aerosols. In this study, in order to complement the daytime satellite measurements, I used the data from Visible Infrared …


Suspended Sediment Transport Revealed By Patterns In Turbidity And Electrical Conductivity Curves In Three Cave Systems In Missouri, Usa., Caroline M. Mierzejewski Mar 2019

Suspended Sediment Transport Revealed By Patterns In Turbidity And Electrical Conductivity Curves In Three Cave Systems In Missouri, Usa., Caroline M. Mierzejewski

LSU Master's Theses

In cave streams, the movement of sediment as suspended and bed loads are linked to the occurrence of precipitation events on the surface. During precipitation events, the discharge of the streams in the basin increases. As those surface streams flow into cave streams via sinkholes or fissures, the discharge in cave streams increase. In addition to changes in discharge, the response of the surface and cave streams to precipitation include changes in turbidity and electrical conductivity of the stream water.

Changes in turbidity (Tu), electrical conductivity (EC), and discharge (Q) of water in the cave stream can be used to …


Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin Thomas Lynch, Douglas R. Leasure, Daniel D. Magoulick Mar 2019

Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin Thomas Lynch, Douglas R. Leasure, Daniel D. Magoulick

United States Geological Survey: Staff Publications

We examined flowalteration-ecology relationships in benthic macroinvertebrate, fish, and crayfish assemblages in Ozark Highland streams, USA, over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013). We hypothesized that: 1) there would be temporal variation in flow alteration-ecology relationships between the two years, 2) flow alteration-ecology relationshipswould be stronger during the drought year vs the flood year, and 3) fish assemblages would show the strongest relationships with flow alteration. We used a quantitative richest-targeted habitat (RTH) method and a qualitative multihabitat (QMH) method to collect macroinvertebrates at 16 USGS gaged sites during both years. …


Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin T. Lynch, Douglas R. Easure, Daniel D. Magoulick Mar 2019

Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin T. Lynch, Douglas R. Easure, Daniel D. Magoulick

United States Geological Survey: Staff Publications

We examined flowalteration-ecology relationships in benthic macroinvertebrate, fish, and crayfish assemblages in Ozark Highland streams, USA, over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013). We hypothesized that: 1) there would be temporal variation in flow alteration-ecology relationships between the two years, 2) flow alteration-ecology relationshipswould be stronger during the drought year vs the flood year, and 3) fish assemblages would show the strongest relationships with flow alteration. We used a quantitative richest-targeted habitat (RTH) method and a qualitative multihabitat (QMH) method to collect macroinvertebrates at 16 USGS gaged sites during both years. …


Using Multi-Indices Approach To Quantify Mangrove Changes Over The Western Arabian Gulf Along Saudi Arabia Coast, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Jingjing Li, K. P. Manikandan, Thomas Piechota Mar 2019

Using Multi-Indices Approach To Quantify Mangrove Changes Over The Western Arabian Gulf Along Saudi Arabia Coast, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Jingjing Li, K. P. Manikandan, Thomas Piechota

Mathematics, Physics, and Computer Science Faculty Articles and Research

Mangroves habitat present an important resource for large coastal communities benefiting from activities such as fisheries, forest products and clean water as well as protection against coastal erosion and climate related extreme events. Yet they are increasingly threatened by natural pressure and anthropogenic activities. We observed an inaccurate distribution of mangroves over the Western Arabian Gulf (WAG) which is a vital habitat and resource for the local ecosystem, according to the United Stated Geological Survey (USGS) mangrove database through spectral analysis. Change detection analysis is conducted on mangrove forests along the Saudi Arabian coast of the WAG for the years …


Seismic Landslide Hazard Mapping For Greater Vancouver, British Columbia, Ali Fallah Yeznabad, Sheri E. Molnar, Hesham M. El Naggar Mar 2019

Seismic Landslide Hazard Mapping For Greater Vancouver, British Columbia, Ali Fallah Yeznabad, Sheri E. Molnar, Hesham M. El Naggar

Western Research Forum

The lower Mainland of southwest British Columbia (BC) hosts about 3.5 million people and significant infrastructures of national importance. Southwestern BC has the highest seismic risk in Canada with significant potential to cause earthquake-induced hazards including tsunamis, liquefaction and landslides. A Cascadia mega-thrust (MW 9) earthquake is predicted to generate $75 billion Canadian dollars in losses. This damage can be resulted from ground shaking or its secondary phenomena like landslides; ground shaking during earthquakes may trigger landslides that can damage or destroy buildings, bury roads and highways and kill and injure people. In Canada, during the past century and …


Tree-Ring Isotopes Adjacent To Lake Superior Reveal Cold Winter Anomalies For The Great Lakes Region Of North America, Steven L. Voelker, Simon S.-Y Wang, Todd E. Dawson, John S. Roden, Christopher J. Still, Fred J. Longstaffe, Avner Ayalon Mar 2019

Tree-Ring Isotopes Adjacent To Lake Superior Reveal Cold Winter Anomalies For The Great Lakes Region Of North America, Steven L. Voelker, Simon S.-Y Wang, Todd E. Dawson, John S. Roden, Christopher J. Still, Fred J. Longstaffe, Avner Ayalon

Earth Sciences Publications

Tree-ring carbon isotope discrimination (Δ13C) and oxygen isotopes (δ18O) collected from white pine (Pinus strobus) trees adjacent to Lake Superior show potential to produce the first winter-specific paleoclimate reconstruction with inter-annual resolution for this region. Isotopic signatures from 1976 to 2015 were strongly linked to antecedent winter minimum temperatures (Tmin), Lake Superior peak ice cover, and regional to continental-scale atmospheric winter pressure variability including the North American Dipole. The immense thermal inertia of Lake Superior underlies the unique connection between winter conditions and tree-ring Δ13C and δ18O …


Earth Observation And Climate Services For Food Security And Agricultural Decision Making In South And Southeast Asia, Faisal M. Qamer, Tsegaue Tadesse, Mir Matin, Walter L. Ellenburg, Benjamin Zaitchik Mar 2019

Earth Observation And Climate Services For Food Security And Agricultural Decision Making In South And Southeast Asia, Faisal M. Qamer, Tsegaue Tadesse, Mir Matin, Walter L. Ellenburg, Benjamin Zaitchik

National Drought Mitigation Center: Faculty Publications

Deliberations on new developments in the use of Earth observation for agriculture and food security in South and Southeast Asia gathered 120 participants to discuss i) agricultural and hydrological drought monitoring and early warning systems, ii) crop mapping and yield estimation, and iii) risk financing and agrometeorological advisory services.


Newgeochemical Evidence For The Origin Of North America's Largest Dune Field, The Nebraska Sand Hills, Central Great Plains, Usa, Daniel R. Muhs, James R. Budahn Feb 2019

Newgeochemical Evidence For The Origin Of North America's Largest Dune Field, The Nebraska Sand Hills, Central Great Plains, Usa, Daniel R. Muhs, James R. Budahn

United States Geological Survey: Staff Publications

The Nebraska SandHills region is the largest dune field inNorthAmerica and has diverse aeolian landforms. It has been active during both the late Pleistocene and late Holocene. Despite decades of study, the source of sediment for this large sand sea is still controversial. Here we report new trace element compositions of aeolian sand that are compared to four hypothesized sediment sources, Tertiary rocks of the Arikaree Group and Ogallala Group, unconsolidated sands of Pliocene age, and Platte River systemsands. All four potential sources have amineralogy that is similar to the Nebraska Sand Hills. K/Rb, K/Ba, Sc-Th-La, Eu/Eu*, LaN/YbN, As/Sb, and …


Building A High-Resolution Vegetation Outlook Model To Monitor Agricultural Drought For The Upper Blue Nile Basin, Ethiopia, Yared Bayissa, Tsegaye Tadesse, Getachew B. Demisse Feb 2019

Building A High-Resolution Vegetation Outlook Model To Monitor Agricultural Drought For The Upper Blue Nile Basin, Ethiopia, Yared Bayissa, Tsegaye Tadesse, Getachew B. Demisse

National Drought Mitigation Center: Faculty Publications

To reduce the impacts of drought, developing an integrated drought monitoring tool and early warning system is crucial and more effective than the crisis management approach that is commonly used in developing countries like Ethiopia. The overarching goal of this study was to develop a higher-spatial-resolution vegetation outlook (VegOut-UBN) model that integrates multiple satellite, climatic, and biophysical input variables for the Upper Blue Nile (UBN) basin. VegOut-UBN uses current and historical observations in predicting the vegetation condition at multiple leading time steps of 1, 3, 6, and 9 dekades. VegOut-UBN was developed to predict the vegetation condition during the main …


Monitoring Sediment Dynamics And Vegetation Competition Based On Micro-Topography And Terrestrial Lidar For Wetland Restoration, Xukai Zhang Jan 2019

Monitoring Sediment Dynamics And Vegetation Competition Based On Micro-Topography And Terrestrial Lidar For Wetland Restoration, Xukai Zhang

LSU Doctoral Dissertations

With the ability to attenuate wave and limit erosion, coastal wetlands are important to protect shoreline for coastal communities. Micro-topography in coastal wetlands has a significant influence on hydrology, habitat variability and ecosystem functions. However, when mapping micro-topography by terrestrial LiDAR in coastal environments, the coverage of dense vegetation leads to a relatively low chance of laser penetration through the canopy to the ground. This dissertation proposes a rapid and flexible terrain mapping solution for the densely vegetated coastal environment by integrating crown structure from terrestrial LiDAR with terrain samples from GPS. The validated results in the study site demonstrate …


Assessing The Evolution Of Soil Moisture And Vegetation Conditions During A Flash Drought–Flash Recovery Sequence Over The South-Central United States, Jason A. Otkin, Yafang Zhong, Eric D. Hunt, Jeff Basara, Mark Svoboda, Martha C. Anderson, Christopher Hain Jan 2019

Assessing The Evolution Of Soil Moisture And Vegetation Conditions During A Flash Drought–Flash Recovery Sequence Over The South-Central United States, Jason A. Otkin, Yafang Zhong, Eric D. Hunt, Jeff Basara, Mark Svoboda, Martha C. Anderson, Christopher Hain

National Drought Mitigation Center: Faculty Publications

This study examines the evolution of soil moisture, evapotranspiration, vegetation, and atmospheric conditions during an unusual flash drought–flash recovery sequence that occurred across the south-central United States during 2015. This event was characterized by a period of rapid drought intensification (flash drought) during late summer that was terminated by heavy rainfall at the end of October that eliminated the extreme drought conditions over a 2-week period (flash recovery). A detailed analysis was performed using time series of environmental variables derived from meteorological, remote sensing, and land surface modeling datasets. Though the analysis revealed a similar progression of cascading effects in …


Soil Moisture Monitoring Using Remote Sensing Data And A Stepwise-Cluster Prediction Model: The Case Of Upper Blue Nile Basin, Ethiopia, Getachew Ayehu, Tsegaye Tadesse, Berhan Gessesse, Yibeltal Yigrem Jan 2019

Soil Moisture Monitoring Using Remote Sensing Data And A Stepwise-Cluster Prediction Model: The Case Of Upper Blue Nile Basin, Ethiopia, Getachew Ayehu, Tsegaye Tadesse, Berhan Gessesse, Yibeltal Yigrem

National Drought Mitigation Center: Faculty Publications

In this study, a residual soil moisture prediction model was developed using the stepwise cluster analysis (SCA) and model prediction approach in the Upper Blue Nile basin. The SCA has the advantage of capturing the nonlinear relationships between remote sensing variables and volumetric soil moisture. The principle of SCA is to generate a set of prediction cluster trees based on a series of cutting and merging process according to a given statistical criterion. The proposed model incorporates the combinations of dual-polarized Sentinel-1 SAR data, normalized difference vegetation index (NDVI), and digital elevation model as input parameters. In this regard, two …


Socioecological Determinants Of Drought Impacts And Coping Strategies For Ranching Operations In The Great Plains, Tonya Haigh, Walter H. Schacht, Cody L. Knutson, Alexander J. Smart, Jerry Volesky, Craig R. Allen, Michael Hayes, Mark E. Burbach Jan 2019

Socioecological Determinants Of Drought Impacts And Coping Strategies For Ranching Operations In The Great Plains, Tonya Haigh, Walter H. Schacht, Cody L. Knutson, Alexander J. Smart, Jerry Volesky, Craig R. Allen, Michael Hayes, Mark E. Burbach

National Drought Mitigation Center: Faculty Publications

In Great Plains rangelands, drought is a recurring disturbance. Ranchers in this region expect to encounter drought but may not be adequately prepared for it. Efforts to encourage drought preparednesswould benefit froma better understanding of the conditions under which managers make decisions to minimize the impacts of drought.We tested the direct andmoderating roles of the drought hazard and the social-ecological context on drought impacts and response. This study was conducted with ranchers in western and central South Dakota and Nebraska following the drought that began in 2012. We surveyed ranchers regarding the effects of the drought and their responses and …


Stable Isotopes Of Clay Minerals From Autoclave Tests Of Oil Sands: Implications For Clay Formation During Steaming Of Alberta Clearwater Oil Sands, Shaoneng He, Fred J. Longstaffe, Zhihong Zhou Jan 2019

Stable Isotopes Of Clay Minerals From Autoclave Tests Of Oil Sands: Implications For Clay Formation During Steaming Of Alberta Clearwater Oil Sands, Shaoneng He, Fred J. Longstaffe, Zhihong Zhou

Earth Sciences Publications

In an effort to evaluate mineral-water isotopic exchange during cyclic steam stimulation (CSS), solutions and<2 μm berthierine-dominated solids from the Clearwater Formation oil sands of Alberta, Canada were analyzed for stable isotope compositions before and after reaction in autoclaves for 1008 h at 250 °C. There was no significant change in solution δ18O and δ2H, which is consistent with the high water/mineral ratio used in the experiments. The solids showed a marked decrease in both δ18O and δ2H following the experiments. Pre-run solids have δ18O of +9.5 to +12.9‰and …


Mapping The Spatial-Temporal Dynamics Of Vegetation Response Lag To Drought In A Semi-Arid Region, Li Hua, Huidong Wang, Haigang Sui, Brian Wardlow, Michael Hayes, Jianxun Wang Jan 2019

Mapping The Spatial-Temporal Dynamics Of Vegetation Response Lag To Drought In A Semi-Arid Region, Li Hua, Huidong Wang, Haigang Sui, Brian Wardlow, Michael Hayes, Jianxun Wang

Center for Advanced Land Management Information Technologies: Publications

Drought, as an extreme climate event, affects the ecological environment for vegetation and agricultural production. Studies of the vegetative response to drought are paramount to providing scientific information for drought risk mitigation. In this paper, the spatial-temporal pattern of drought and the response lag of vegetation in Nebraska were analyzed from 2000 to 2015. Based on the long-term Daymet data set, the standard precipitation index (SPI) was computed to identify precipitation anomalies, and the Gaussian function was applied to obtain temperature anomalies. Vegetation anomaly was identified by dynamic time warping technique using a remote sensing Normalized Difference Vegetation Index (NDVI) …


Monitoring Spatial And Temporal Variabilities Of Gross Primary Production Using Maiac Modis Data, Marcos Fernandez-Martinez, Rong Yu, John Gamon, Gabriel Hmimina, Iolanda Filella, Manuela Balzarolo, Benjamin Stocker, Josep Penuelas Jan 2019

Monitoring Spatial And Temporal Variabilities Of Gross Primary Production Using Maiac Modis Data, Marcos Fernandez-Martinez, Rong Yu, John Gamon, Gabriel Hmimina, Iolanda Filella, Manuela Balzarolo, Benjamin Stocker, Josep Penuelas

Center for Advanced Land Management Information Technologies: Publications

Remotely sensed vegetation indices (RSVIs) can be used to efficiently estimate terrestrial primary productivity across space and time. Terrestrial productivity, however, has many facets (e.g., spatial and temporal variability, including seasonality, interannual variability, and trends), and different vegetation indices may not be equally good at predicting them. Their accuracy in monitoring productivity has been mostly tested in single-ecosystem studies, but their performance in different ecosystems distributed over large areas still needs to be fully explored. To fill this gap, we identified the facets of terrestrial gross primary production (GPP) that could be monitored using RSVIs. We compared the temporal and …


Prehistoric Chaco Canyon, New Mexico: Importation Of Meat And Mmaize, Larry V. Benson, Deanna Grimstead, John R. Stein, David A. Rith, Terry L. Plowman Jan 2019

Prehistoric Chaco Canyon, New Mexico: Importation Of Meat And Mmaize, Larry V. Benson, Deanna Grimstead, John R. Stein, David A. Rith, Terry L. Plowman

United States Geological Survey: Staff Publications

In a recent paper, Benson and Grimstead (2019) determined that only minimal amounts of maize could have been grown in Chaco Canyon due to its aridity, short growing season, and frequent summer flooding of the valley floor. In this paper it is shown that deer and rabbit densities within semiarid regions such as the Canyon are such that 2300 Canyon residents would eliminate essentially all small and large mammals within a year. This implies that food (meat and maize) must have been imported from one or more outlying areas to feed the Canyon's residential population. This would have entailed ~18,000 …


Chaco Canyon, New Mexico: A Caretaker City And A Pilgrimage Destination, Larry Benson, Deanna N. Grimstead, John R. Stein, David A. Roth, Terry I. Plowman Jan 2019

Chaco Canyon, New Mexico: A Caretaker City And A Pilgrimage Destination, Larry Benson, Deanna N. Grimstead, John R. Stein, David A. Roth, Terry I. Plowman

United States Geological Survey: Staff Publications

Some Southwestern archaeologists continue to ascribe to the hypothesis that Chaco was agriculturally productive to the point that it could support at least a few thousand full-time residents. This paper suggests an alternative hypothesis; i.e., Chaco was marginally productive and could only support a few hundred permanent residents. Isotopic analysis of mammal teeth found in trenches cut through platform mounds fronting Pueblo Bonito indicate the possibility that much of the meat consumed by Chacoan residents and visitors came from higher elevation sites bordering the San Juan Basin. We suggest that resident population estimates based on great house room numbers and …


Spatial Conservation Planning Under Uncertainty: Adapting To Climate Change Risks Using Modern Portfolio Theory, Mitchell J. Eaton, Simeon Yurek, Zulqarnain Haider, Julien Martin, Fred Johnson, Bradley J. Udell, Hadi Charkhgard, Changhyun Kwon Jan 2019

Spatial Conservation Planning Under Uncertainty: Adapting To Climate Change Risks Using Modern Portfolio Theory, Mitchell J. Eaton, Simeon Yurek, Zulqarnain Haider, Julien Martin, Fred Johnson, Bradley J. Udell, Hadi Charkhgard, Changhyun Kwon

United States Geological Survey: Staff Publications

Climate change and urban growth impact habitats, species, and ecosystem services. To buffer against global change, an established adaptation strategy is designing protected areas to increase representation and complementarity of biodiversity features. Uncertainty regarding the scale and magnitude of landscape change complicates reserve planning and exposes decision makers to the risk of failing to meet conservation goals. Conservation planning tends to treat risk as an absolute measure, ignoring the context of the management problem and risk preferences of stakeholders. Application of risk management theory to conservation emphasizes the diversification of a portfolio of assets, with the goal of reducing the …