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Articles 1 - 9 of 9
Full-Text Articles in Social and Behavioral Sciences
Responses Of Land Surface Phenology To Wildfire Disturbances In The Western United States Forests, Jianmin Wang
Responses Of Land Surface Phenology To Wildfire Disturbances In The Western United States Forests, Jianmin Wang
Electronic Theses and Dissertations
Land surface phenology (LSP) characterizes the seasonal dynamics in the vegetation communities observed for a satellite pixel and it has been widely associated with global climate change. However, LSP and its long-term trend can be influenced by land disturbance events, which could greatly interrupt the LSP responses to climate change. Wildfire is one of the main disturbance agents in the western United States (US) forests, but its impacts on LSP have not been investigated yet. To gain a comprehensive understanding of the LSP responses to wildfires in the western US forests, this dissertation focused on three research objectives: (1) to …
Burning With Potential: Understanding The Relationship Between Biochar And Agriculture Of The Northern Glaciated Plains Ecoregion, Kaitlyn Abrahamson
Burning With Potential: Understanding The Relationship Between Biochar And Agriculture Of The Northern Glaciated Plains Ecoregion, Kaitlyn Abrahamson
Electronic Theses and Dissertations
Achieving global sustainable agriculture is one of the most incredible challenges of this century, yet many continue to try to solve this problem through the development of precision technologies. Biotechnologies, such as biochar, can perform like a precision technology while protecting agricultural land from soil erosion and fertility loss. The Northern Glaciated Plains ecoregion of the United States is little researched in the benefits from the use of biochar through improved soil nutrient capture and water retention, crop health improvements, and yield increases. The study plot has four sections of corn stover biochar and eight sections of control sections. This …
Cross Calibration And Validation Of Landsat 8 Oli And Sentinel 2a Msi, M. M. Farhad
Cross Calibration And Validation Of Landsat 8 Oli And Sentinel 2a Msi, M. M. Farhad
Electronic Theses and Dissertations
This work describes a proposed radiometric cross calibration between the Landsat 8 Operational Land Imager (OLI) and Sentinel 2A Multispectral Instrument (MSI) sensors. The cross calibration procedure involves i) correction of the MSI data to account for spectral band differences with the OLI; and ii) correction of BRDF effects in the data from both sensors using a new model accounting for the view zenith/azimuth angles in addition to the solar zenith/view angles. Following application of the spectral and BRDF corrections, standard least-squares linear regression is used to determine the cross calibration gain and offset in each band. Uncertainties related to …
A Study Of African Savanna Vegetation Structure, Patterning, And Change, Christoffer R. Axelsson
A Study Of African Savanna Vegetation Structure, Patterning, And Change, Christoffer R. Axelsson
Electronic Theses and Dissertations
African savannas cover roughly half of the continent, are home to a great diversity of wildlife, and provide ecosystem services to large populations. Savannas showcase a great diversity in vegetation structure, resulting from variation in climatic, edaphic, topographic, and biological factors. Fires play a large role as savannas are the most frequently burned ecosystems on Earth. To study how savanna vegetation structure shifts with environmental factors, it is necessary to gather site data covering the full gradient of climatic and edaphic conditions. Several earlier studies have used coarse resolution satellite remote sensing data to study variation in woody cover. These …
Mapping And Risk Assessment Of Juniper Encroachment Into A Prairie Landscape, Kyle D. Kaskie
Mapping And Risk Assessment Of Juniper Encroachment Into A Prairie Landscape, Kyle D. Kaskie
Electronic Theses and Dissertations
Juniper encroachment is a considerable threat to the prairie ecosystems of the Great Plains because it has the potential to alter native grasslands by changing soil characteristics, limiting herbaceous biomass, and hindering native community regeneration. Accurate maps of juniper cover and predictions of areas at risk for future expansion are needed to support proactive management measures. Therefore, our objectives are to: (1) Develop a practical workflow for large-scale juniper mapping using Landsat 8 Operational Land Imager (OLI) imagery and partial unmixing techniques, (2) Compare the classification accuracies from the resulting map based on different juniper density thresholds and different types …
Land Surface Phenologies And Seasonalities Using Cool Earthlight In Temperate And Tropical Croplands, Woubet Gashaw Alemu
Land Surface Phenologies And Seasonalities Using Cool Earthlight In Temperate And Tropical Croplands, Woubet Gashaw Alemu
Electronic Theses and Dissertations
In today’s world of increasing food insecurity due to more frequent and extreme events (droughts, floods), a comprehensive understanding of global cropland dynamics is critically needed. Land surface parameters derived from the passive microwave Advanced Microwave Scanning Radiometer on EOS (AMSR-E) and AMSR2 data enable monitoring of cropland dynamics and they can complement visible to near infrared (VNIR) and thermal infrared (TIR) data. Passive microwave data are less sensitive to atmospheric effects, cloud contamination, and solar illumination constraints resulting in finer temporal resolution suitable to track the temporal progression of cropland cover development compared to the VNIR data that has …
Using Remote Sensing To Estimate Crop Water Use To Improve Irrigation Water Management, Arturo Reyes-Gonzalez
Using Remote Sensing To Estimate Crop Water Use To Improve Irrigation Water Management, Arturo Reyes-Gonzalez
Electronic Theses and Dissertations
Irrigation water is scarce. Hence, accurate estimation of crop water use is necessary for proper irrigation managements and water conservation. Satellite-based remote sensing is a tool that can estimate crop water use efficiently. Several models have been developed to estimate crop water requirement or actual evapotranspiration (ETa) using remote sensing. One of them is the Mapping EvapoTranspiration at High Resolution using Internalized Calibration (METRIC) model. This model has been compared with other methods for ET estimations including weighing lysimeters, pan evaporation, Bowen Ratio Energy Balance System (BREBS), Eddy Covariance (EC), and sap flow. However, comparison of METRIC model outputs to …
Simulating The Impacts Of Land-Use Land-Cover Changes On Cropland Carbon Fluxes In The Midwest Of The United States, Zhengpeng Li
Simulating The Impacts Of Land-Use Land-Cover Changes On Cropland Carbon Fluxes In The Midwest Of The United States, Zhengpeng Li
Electronic Theses and Dissertations
Understanding the major drivers of the cropland carbon fluxes is important for carbon management and greenhouse gas mitigation in agriculture. Past studies found that agricultural land-use and land-cover (LULC) changes, such as changes in cropland production technologies, tillage practices, and planted crop species, could have large impacts on carbon fluxes. However, the impacts remain highly uncertain at regional to global scales. Satellite remote sensing is commonly used to create products with geospatial information on LULC changes. This geospatial information can be integrated into biogeochemical models to simulate the spatial and temporal patterns of carbon fluxes. We used the General Ensemble …
Impacts Of Urban Areas On Vegetation Development Along Rural-Urban Gradients In The Upper Midwest: 2003-2012, Cole Krehbiel
Impacts Of Urban Areas On Vegetation Development Along Rural-Urban Gradients In The Upper Midwest: 2003-2012, Cole Krehbiel
Electronic Theses and Dissertations
Between one-third and one-half of Earth’s land surface has been directly altered by humans, with the remainder comprised of “human-dominated ecosystems” (Vitousek et al. 2008). Earth’s population has surpassed seven billion, projected to increase by 2.5 billion by 2050 in urban areas alone (United Nations 2014). The rapid urbanization of our planet drives global environmental changes in hydrosystems, biodiversity, biogeochemical cycles, land use and land cover, and climate (Grimm et al. 2008). Urban areas alter local atmospheric conditions by modifying surface albedo and consequently evapotranspiration, releasing energy through anthropogenic heat sources, and increasing atmospheric aerosols, leading to increased temperatures in …