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Articles 1 - 8 of 8

Full-Text Articles in Physical Sciences and Mathematics

A Cross Comparison Of Spatiotemporally Enhanced Springtime Phenological Measurements From Satellites And Ground In A Northern U.S. Mixed Forest, Liang Liang, Mark D. Schwartz, Zhuosen Wang, Feng Gao, Crystal B. Schaaf, Bin Tan, Jeffrey T. Morisette, Xiaoyang Zhang Dec 2014

A Cross Comparison Of Spatiotemporally Enhanced Springtime Phenological Measurements From Satellites And Ground In A Northern U.S. Mixed Forest, Liang Liang, Mark D. Schwartz, Zhuosen Wang, Feng Gao, Crystal B. Schaaf, Bin Tan, Jeffrey T. Morisette, Xiaoyang Zhang

GSCE Faculty Publications

Cross comparison of satellite-derived land surface phenology (LSP) and ground measurements is useful to ensure the relevance of detected seasonal vegetation change to the underlying biophysical processes. While standard 16-day and 250-m Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation index (VI)-based springtime LSP has been evaluated in previous studies, it remains unclear whether LSP with enhanced temporal and spatial resolutions can capture additional details of ground phenology. In this paper, we compared LSP derived from 500-m daily MODIS and 30-m MODIS-Landsat fused VI data with landscape phenology (LP) in a northern U.S. mixed forest. LP was previously developed from intensively observed …


Earlier Vegetation Green-Up Has Reduced Spring Dust Storms, Bihang Fan, Li Guo, Ning Li, Jin Chen, Henry Lin, Xiaoyang Zhang, Miaogen Shen, Yuhan Rao, Cong Wang, Lei Ma Oct 2014

Earlier Vegetation Green-Up Has Reduced Spring Dust Storms, Bihang Fan, Li Guo, Ning Li, Jin Chen, Henry Lin, Xiaoyang Zhang, Miaogen Shen, Yuhan Rao, Cong Wang, Lei Ma

GSCE Faculty Publications

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating above ground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date …


Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George C. Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Bevery E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker Oct 2014

Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George C. Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Bevery E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker

GSCE Faculty Publications

The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth's climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale eddy covariance flux observations from towers to the continental scale by integrating flux observations, meteorology, stand age, aboveground biomass, and a proxy for canopy nitrogen concentrations from AmeriFlux and Fluxnet-Canada Research Network as well as a variety of satellite data streams from the MODIS …


Sensitivity Of Mesoscale Modeling Of Smoke Direct Radiative Effect To The Emission Inventory: A Case Study In Northern Sub-Saharan African Region, Feng Zhang, Jun Wang, Charles Ichoku, Edward J. Hyer, Zhifeng Yang, Cui Ge, Shenjian Su, Xiaoyang Zhang, Shobha Kondragunta, Christine Wiedinmyer, Johannes W. Kaiser, Arlindo Da Silva Jul 2014

Sensitivity Of Mesoscale Modeling Of Smoke Direct Radiative Effect To The Emission Inventory: A Case Study In Northern Sub-Saharan African Region, Feng Zhang, Jun Wang, Charles Ichoku, Edward J. Hyer, Zhifeng Yang, Cui Ge, Shenjian Su, Xiaoyang Zhang, Shobha Kondragunta, Christine Wiedinmyer, Johannes W. Kaiser, Arlindo Da Silva

GSCE Faculty Publications

An ensemble approach is used to examine the sensitivity of smoke loading and smoke direct radiative effect in the atmosphere to uncertainties in smoke emission estimates. Seven different fire emission inventories are applied independently to WRF-Chem model (v3.5) with the same model configuration (excluding dust and other emission sources) over the northern sub-Saharan African (NSSA) biomass-burning region. Results for November and February 2010 are analyzed, respectively representing the start and end of the biomass burning season in the study region. For February 2010, estimates of total smoke emission vary by a factor of 12, but only differences by factors of …


Interannual Variation In Biomass Burning And Fire Seasonality Derived From Geostationary Satellite Data Across The Contiguous United States From 1995 To 2011, Xiaoyang Zhang, Shobha Kondragunta, David Roy Jun 2014

Interannual Variation In Biomass Burning And Fire Seasonality Derived From Geostationary Satellite Data Across The Contiguous United States From 1995 To 2011, Xiaoyang Zhang, Shobha Kondragunta, David Roy

GSCE Faculty Publications

Wildfires exhibit a strong seasonality that is driven by climatic factors and human activities. Although the fire seasonality is commonly determined using burned area and fire frequency, it could also be quantified using biomass consumption estimates that directly represent biomass loss (a combination of the area burned and the fuel loading). Therefore, in this study a data set of long-term biomass consumed was derived from geostationary satellite data to explore the interannual variation in the fire seasonality and the possible impacts of climate change and land management practices across the Contiguous United States (CONUS). Specifically, daily biomass consumed data were …


The Development And Application Of A Larval Pallid Sturgeon (Scaphirhynchus Albus) Bioenergetics Model, Laura B. Heironimus Jan 2014

The Development And Application Of A Larval Pallid Sturgeon (Scaphirhynchus Albus) Bioenergetics Model, Laura B. Heironimus

Electronic Theses and Dissertations

Pallid Sturgeon Scaphirhynchus albus are native fish of the Missouri and lower Mississippi River basins and currently listed as an endangered species under the Federal Endangered Species Act. As a result of anthropogenic alterations within the Missouri River, including dredging, channelization, and construction of large reservoirs, Pallid Sturgeon reproduction is reduced or eliminated throughout the species range. Due to a lack of wild progeny, little is known of the larval Pallid Sturgeon and their habitat or environmental requirements. To increase knowledge on the larval Pallid Sturgeon’s physiological requirements for growth and survival, the objective of this study was to develop …


Detecting The Influence Of Best Management Practices On Vegetation Near Ephemeral Streams With Landsat Data, Matthew Rigge, Alexander Smart, Bruce Wylie, Kendall De Van Kamp Jan 2014

Detecting The Influence Of Best Management Practices On Vegetation Near Ephemeral Streams With Landsat Data, Matthew Rigge, Alexander Smart, Bruce Wylie, Kendall De Van Kamp

Natural Resource Management Faculty Publications

Various best management practices (BMPs) have been implemented on rangelands with the goals of controlling nonpoint sourcepollution, reducing the impact of livestock in ecologically important riparian areas, and improving grazing distribution.Providing off-stream water sources to livestock in pastures, cross-fencing, and rotational grazing are common rangeland BMPsthat have demonstrated success in drawing livestock grazing pressure away from streams. We evaluated the effects of rangelandBMP implementation with six commercial-scale pastures in the northern mixed-grass prairie. Four pastures received a BMPsuite consisting of off-stream water, cross-fencing, and deferred-rotation grazing, and two pastures did not receive BMPs. Wehypothesized that the BMPs increased the quantity …


Determining Impacts Of Mountain Lions On Bighorn Sheep And Other Prey Sources In The Black Hills, Joshua B. Smith Jan 2014

Determining Impacts Of Mountain Lions On Bighorn Sheep And Other Prey Sources In The Black Hills, Joshua B. Smith

Electronic Theses and Dissertations

From 2009 to 2013, we assessed cougar (Puma concolor) feeding habits and bighorn sheep (Ovis canadensis) population dynamics in the Black Hills, South Dakota. We used Global Positioning System (GPS) telemetry to locate 1,506 cougar feeding events and found deer (Odocoileus spp.; 83%), primarily white-tailed deer (O. virginianus), dominated cougar diets. Overall ungulate kill rate averaged 0.79 ungulates/week (range = 0.13–1.75 ungulates/week), and was significantly higher (P < 0.001) in summer (xˉ = 0.92; SE = 0.06) than in winter (xˉ = 0.62; SE = 0.06). In contrast, biomass consumed was significantly higher (P = 0.033) in winter (xˉ = 8.23 kg/day; SE = 0.96) than in summer (xˉ = 5.45 kg/day; SE = 0.43), primarily as a result of increased scavenging (winter = 0.21 events/week; summer = 0.08 events/week), which represents the highest documented rate for cougar populations studied. We also documented a relatively high rate of chronic wasting disease- (CWD) infected elk in 2 cougar (1 male; 1 female) diets (64%; 95% CI = 50.3–78.3%) and speculate that CWD infection likely increased elk predation risk. Annual lamb survival was 0.02 (SE = 0.01) with pneumonia (36%) and predation (30%) the leading causes of mortality. We found pneumonia and predation were temporally heterogeneous with lambs most susceptible to predation during the first 2–3 weeks of life, while the greatest risk from pneumonia occurred from weeks 4–8. Annual ewe survival was 0.81 (SE = 0.04) with pneumonia (19%) and predation (19%) the leading causes of documented mortality; 48% were unknown. Additionally, we used vaginal implant transmitters (VITs) to assess capture efficiency and document parturition and neonate lamb bed site selection for bighorn sheep. We found successful VITs increased capture efficiency (95%) over unsuccessfully-vitted ewes (81%) and ewes not equipped with VITs (70%). Bighorn ewes selected for rugged terrain at both macro- and microhabitat scales, while at the macrohabitat scale ewes selected for areas that were close to perennial streams on south and west facing slopes and against anthropogenic disturbance. At the microhabitat scale, neonate lambs tended to select for greater cover and against north facing slopes.