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Remote Sensing

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Articles 91 - 120 of 209

Full-Text Articles in Physical and Environmental Geography

Detecting Coastal Marsh Change From Aerial Imagery Using Spectral And Textural Methods: Pascagoula River Estuary, Mississippi, 1955-2014, Margaret Claire Bell Waldron May 2019

Detecting Coastal Marsh Change From Aerial Imagery Using Spectral And Textural Methods: Pascagoula River Estuary, Mississippi, 1955-2014, Margaret Claire Bell Waldron

Master's Theses

As sea level rise accelerates, coastal marsh ecosystems are increasingly vulnerable. Vertical accretion rates must exceed or keep pace with rates of sea level rise to prevent transition to open water or inland migration of marsh vegetation. While some marsh systems along the northern Gulf of Mexico coast have remained stable, others, e.g., the marshes of the Louisiana Gulf Coast, have experienced high rates of conversion to open water. This study examined the historical extent of intertidal marsh at the mouth of the Pascagoula River in Jackson County, Mississippi to determine whether marsh extent changed during the period 1955-2014 and …


An Evaluation Of Sentinel-1 And Sentinel-2 For Land Cover Classification, Aaron Meneghini Apr 2019

An Evaluation Of Sentinel-1 And Sentinel-2 For Land Cover Classification, Aaron Meneghini

Sustainability and Social Justice

This study evaluates Sentinel-1 and Sentinel-2 remotely sensed images for tropical land cover classification. The dual polarized Sentinel-1 VV and VH backscatter images and four 10-meter multispectral bands of Sentinel-2 were used to create six land cover classification images across two study areas along the border of the Bolivian Pando Department and the Brazilian state of Acre. Results indicate that Sentinel-2 multispectral bands possess a higher overall performance in delineating land cover types than the Sentinel-1 backscatter bands. Sentinel-1 backscatter bands delineated land cover types based on their surficial properties but did not facilitate the separation of similarly textured classes. …


Augmenting Land Cover/Land Use Classification By Incorporating Information From Land Surface Phenology: An Application To Quantify Recent Cropland Expansion In South Dakota, Lan Hoang Nguyen Jan 2019

Augmenting Land Cover/Land Use Classification By Incorporating Information From Land Surface Phenology: An Application To Quantify Recent Cropland Expansion In South Dakota, Lan Hoang Nguyen

Electronic Theses and Dissertations

Understanding rapid land change in the U.S. NGP region is not only critical for management and conservation of prairie habitats and ecosystem services, but also for projecting production of crops and biofuels and the impacts of land conversion on water quality and rural transportation infrastructure. Hence, it raises the need for an LCLU dataset with good spatiotemporal coverage as well as consistent accuracy through time to enable change analysis. This dissertation aims (1) to develop a novel classification method, which utilizes time series images from comparable sensors, from the perspective of land surface phenology, and (2) to apply the land …


Characterizing Spatiotemporal Patterns Of White Mold In Soybean Across South Dakota Using Remote Sensing, Confiance L. Mfuka Jan 2019

Characterizing Spatiotemporal Patterns Of White Mold In Soybean Across South Dakota Using Remote Sensing, Confiance L. Mfuka

Electronic Theses and Dissertations

Soybean is among the most important crops, cultivated primarily for beans, which are used for food, feed, and biofuel. According to FAO, the United States was the biggest soybeans producer in 2016. The main soybean producing regions in the United States are the Corn Belt and the lower Mississippi Valley. Despite its importance, soybean production is reduced by several diseases, among which Sclerotinia stem rot, also known as white mold, a fungal disease that is caused by the fungus Sclerotinia sclerotiorum is among the top 10 soybean diseases. The disease may attack several plants and considerably reduce yield. According to …


Classification Of North Africa For Use As An Extended Pseudo Invariant Calibration Sites (Epics) For Radiometric Calibration And Stability Monitoring Of Optical Satellite Sensors, Mahesh Shrestha Jan 2019

Classification Of North Africa For Use As An Extended Pseudo Invariant Calibration Sites (Epics) For Radiometric Calibration And Stability Monitoring Of Optical Satellite Sensors, Mahesh Shrestha

Electronic Theses and Dissertations

An increasing number of Earth-observing satellite sensors are being launched to meet the insatiable demand for timely and accurate data to help the understanding of the Earth’s complex systems and to monitor significant changes to them. The quality of data recorded by these sensors is a primary concern, as it critically depends on accurate radiometric calibration for each sensor. Pseudo Invariant Calibration Sites (PICS) have been extensively used for radiometric calibration and temporal stability monitoring of optical satellite sensors. Due to limited knowledge about the radiometric stability of North Africa, only a limited number of sites in the region are …


How Are Interannual Variations Of Land Surface Phenology In The Highland Pastures Of Kyrgyzstan Modulated By Terrain, Snow Cover Seasonality, And Climate Oscillations? An Investigation Using Multi-Source Remote Sensing Data, Monika Anna Tomaszewska Jan 2019

How Are Interannual Variations Of Land Surface Phenology In The Highland Pastures Of Kyrgyzstan Modulated By Terrain, Snow Cover Seasonality, And Climate Oscillations? An Investigation Using Multi-Source Remote Sensing Data, Monika Anna Tomaszewska

Electronic Theses and Dissertations

In the semiarid, continental climates of montane Central Asia, with its constant moisture deficit and low relative humidity, agropastoralism constitutes the foundation of the rural economy. In Kyrgyzstan, an impoverished, landlocked republic in Central Asia, herders of the highlands practice vertical transhumance—the annual movement of livestock to higher elevation pastures to take advantage of seasonally available forage resources. Dependency on pasture resource availability during the short mountain growing season makes herds and herders susceptible to changing weather and climate patterns. This dissertation focuses on using remote sensing observations over the highland pastures in Kyrgyzstan to address five interrelated topics: (i) …


Land Cover Changes Within And Around Protected Areas In Côte D’Ivoire From 1986 To 2017: A Case Study Of The Mabi-Yaya-Songan-Tamin Reserved Forests, Olena Boiko Jan 2019

Land Cover Changes Within And Around Protected Areas In Côte D’Ivoire From 1986 To 2017: A Case Study Of The Mabi-Yaya-Songan-Tamin Reserved Forests, Olena Boiko

Electronic Theses and Dissertations

Tropical forests mitigate climate change, provide habitat for the most biologically diverse terrestrial communities, and yield ecosystem services that support human wellbeing. These forests are some of the most threatened ecosystems because of the increasing human impact on the environment. Côte d’Ivoire has one of the highest deforestation rates in sub-Saharan Africa, and the expansion of agriculture to produce cash crops, such as cocoa and rubber, is presented as the primary reason for forest loss. These changes are apparent even within the boundaries of the protected areas, which raises concerns about the effectiveness of the protection strategies. This project illustrates …


Remote Sensing Of Avalanche Paths In Glacier National Park, Montana, Morgan Voss Jan 2019

Remote Sensing Of Avalanche Paths In Glacier National Park, Montana, Morgan Voss

Graduate Student Theses, Dissertations, & Professional Papers

Snow avalanches are the common form of mass wasting in the high mountain environments of Glacier National Park (GNP), Montana. These natural disturbances play important roles in mountain ecosystems by regularly disturbing montane systems, providing critical habitat for some species, transporting debris, and influencing vegetation and fire dynamics. Since the 1900s, natural avalanche-related activity recorded along important transportation corridors within the park has frequently disrupted transportation.

While many of the steep slopes of GNP are susceptible to avalanching, formal inventories exist only for small, critical portions of the park and they vary substantially from one another. GNP’s protected status does …


Visualizing Barrier Dune Topographic State Space And Inference Of Resilience Properties, Li-Chih Hsu Jan 2019

Visualizing Barrier Dune Topographic State Space And Inference Of Resilience Properties, Li-Chih Hsu

Theses and Dissertations--Geography

The linkage between barrier island morphologies and dune topographies, vegetation, and biogeomorphic feedbacks, has been examined. The two-fold stability domain (i.e., overwash-resisting and overwash-reinforcing stability domains) model from case studies in a couple of islands along the Georgia Bight and Virginia coast has been proposed to examine the resilience properties in the barrier dune systems. Thus, there is a need to examine geographic variations in the dune topography among and within islands. Meanwhile, previous studies just analyzed and compared dune topographies based on transect-based point elevations or dune crest elevations; therefore, it is necessary to further examine dune topography in …


Tropical Forest Canopy Height And Aboveground Biomass Estimation Using Airborne Lidar And Landsat-8 Data, A Sensitivity Study With Respect To Landsat-8 Data Temporal Availability, In Mai Ndombe Province, Democratic Republic Of Congo, Herve B. Kashongwe Jan 2019

Tropical Forest Canopy Height And Aboveground Biomass Estimation Using Airborne Lidar And Landsat-8 Data, A Sensitivity Study With Respect To Landsat-8 Data Temporal Availability, In Mai Ndombe Province, Democratic Republic Of Congo, Herve B. Kashongwe

Electronic Theses and Dissertations

Tropical forests’ structure information, such as forest canopy height, is a key component in any estimate of carbon stock. Tropical rainforests constitute the most forested ecosystems that harbor the largest biodiversity on Earth and store more carbon (above and belowground biomass) than any other ecosystem in the world. However, estimates of forest canopy structure is lacking over most of the regions that host this ecosystem because of both the structure’s complexity of this ecosystems and the incomplete or lack of up-to-date national forest inventory data necessary to derive forest canopy height and aboveground biomass. This study explores the capability of …


Object-Based Supervised Machine Learning Regional-Scale Land-Cover Classification Using High Resolution Remotely Sensed Data, Christopher A. Ramezan Jan 2019

Object-Based Supervised Machine Learning Regional-Scale Land-Cover Classification Using High Resolution Remotely Sensed Data, Christopher A. Ramezan

Graduate Theses, Dissertations, and Problem Reports (ETD)

High spatial resolution (HR) (1m – 5m) remotely sensed data in conjunction with supervised machine learning classification are commonly used to construct land-cover classifications. Despite the increasing availability of HR data, most studies investigating HR remotely sensed data and associated classification methods employ relatively small study areas. This work therefore drew on a 2,609 km2, regional-scale study in northeastern West Virginia, USA, to investigates a number of core aspects of HR land-cover supervised classification using machine learning. Issues explored include training sample selection, cross-validation parameter tuning, the choice of machine learning algorithm, training sample set size, and feature selection. A …


[Introduction To] Collateral Values: The Natural Capital Created By Landscapes Of War., Todd R. Lookingbill, Peter D. Smallwood Jan 2019

[Introduction To] Collateral Values: The Natural Capital Created By Landscapes Of War., Todd R. Lookingbill, Peter D. Smallwood

Bookshelf

This book explores the unanticipated benefits that may arise after wars and conflicts, showing how the preservation of battlefields and the establishment of borderlands can create natural capital in the former landscapes of war. The editors call this Collateral Value, in contrast to the collateral damage that war inflicts upon infrastructure, natural capital, and human capital. The book includes case studies recounting successes and failures, opportunities and risks, and ambitious proposals.

The book is organized in two sections. The first visits U.S., English, and French battlefield sites dating from medieval England to World War I. The second explores borderlands located …


Crown-Level Mapping Of Tree Species And Health From Remote Sensing Of Rural And Urban Forests, Fang Fang Jan 2019

Crown-Level Mapping Of Tree Species And Health From Remote Sensing Of Rural And Urban Forests, Fang Fang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Tree species composition and health are key attributes for rural and urban forest biodiversity, and ecosystem services preservation. Remote sensing has facilitated extraordinary advances in estimating and mapping tree species composition and health. Yet previous sensors and algorithms were largely unable to resolve individual tree crowns and discriminate tree species or health classes at this essential spatial scale due to the low image spectral and spatial resolution. However, current available very high spatial resolution (VHR) remote sensing data can begin to resolve individual tree crowns and measure their spectral and structural qualities with unprecedented precision. Moreover, various machine learning algorithms …


Investigating Smoke Aerosol Emission Coefficients Using Modis Active Fire And Aerosol Products – A Case Study In The Conus And Indonesia, Xiaoman Lu, Xiaoyang Zhang, Fangjun Li, Mark Cochrane Dec 2018

Investigating Smoke Aerosol Emission Coefficients Using Modis Active Fire And Aerosol Products – A Case Study In The Conus And Indonesia, Xiaoman Lu, Xiaoyang Zhang, Fangjun Li, Mark Cochrane

Global Land Surface Season Data Sets

This data set is in relation to the paper of the same title, which has been submitted to the Journal of Geophysical Research: Biogeosciences.

Instructions for viewing the data in “Readme.txt”





Estimation Of The Relationship Between Satellite-Derived Vegetation Indices And Live Fuel Moisture Towards Wildfire Risk In Southern California, Kristen Whitney, Seung Hee Kim, Shenyue Jia, Menas Kafatos Aug 2018

Estimation Of The Relationship Between Satellite-Derived Vegetation Indices And Live Fuel Moisture Towards Wildfire Risk In Southern California, Kristen Whitney, Seung Hee Kim, Shenyue Jia, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Southern California possesses a Mediterranean climate having semi-arid to arid characteristics and contains shrubland areas at high risk to wildfire. To assess wildfire danger, fire agencies have been monitoring the moisture of vegetation, called live fuel moisture (LFM), using field-based sampling. Unfortunately, spatial and temporal resolution of live fuel moisture data are significantly limited because sampling is labor intensive. Remote sensing satellite data has been used to monitor vegetation moisture content and health of shrublands. Therefore, a potential approach to overcome the limitations of manual measurements of live fuel moisture is to use vegetation indices (VIs) derived from satellite data. …


Drone Photography Vs. Light Detection And Ranging (Lidar) Data - Which Source Is Best Utilized In 3-Dimensional Modeling Applications?, Austin Valentine Jun 2018

Drone Photography Vs. Light Detection And Ranging (Lidar) Data - Which Source Is Best Utilized In 3-Dimensional Modeling Applications?, Austin Valentine

Student Scholarship & Creative Works

Drone Photography vs. Light Detection and Ranging (LiDAR) Data — Which Source is Best Utilized in 3-Dimensional Modeling Applications? is an evaluation essay comparing the analysis and modeling of both drone photography and LiDAR data. This paper gives a brief introduction into my choice of utilization between these two techniques, both of which were applied to 3-dimensional modeling of the Kincaid Mounds Archaeological site in southern Illinois. Thus, illustrating some of the advantages and disadvantages associated with both methods.


African Savanna Vegetation Model, Christoffer Axelsson Jun 2018

African Savanna Vegetation Model, Christoffer Axelsson

Graduate Student Datasets and Models

The project aimed at creating a model that can simulate the effect of environmental factors on trees and grasses in an African savanna landscape. It enables simulating the growth of woody and herbaceous vegetation in an African savanna landscape, where the user can define the environmental conditions. Input to the model includes:

  • Monthly precipitation
  • Fire regime
  • Grazing pressure
  • Soil type
  • Slope
  • Attributes of the woody species, such as maximum crown size and sensitivity to light conditions, drought, and fire.


Large Scale Climate Oscillation Impacts On Temperature, Precipitation And Land Surface Phenology In Central Asia, Kirsten M. De Beurs, Geoffrey Henebry, Braden C. Owsley, Irina N. Sokolik Jun 2018

Large Scale Climate Oscillation Impacts On Temperature, Precipitation And Land Surface Phenology In Central Asia, Kirsten M. De Beurs, Geoffrey Henebry, Braden C. Owsley, Irina N. Sokolik

GSCE Faculty Publications

Central Asia has been rapidly changing in multiple ways over the past few decades. Increases in temperature and likely decreases in precipitation in Central Asia as the result of global climate change are making one of the most arid regions in the world even more susceptible to large-scale droughts. Global climate oscillations, such as the El Ni ̃no–Southern Oscillation, have previously been linked to observed weather patterns in Central Asia. However, until now it has been unclear how the different climate oscillations act simultaneously to affect the weather and subsequently the vegetated land surface in Central Asia.We fit well-established land …


Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry May 2018

Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry

GSCE Faculty Publications

Few studies have examined changing snow seasonality in Central Asia. Here, we analyzed changes in the seasonality of snow cover across Kyrgyzstan (KGZ) over 14 years from 2002/03–2015/16 using the most recent version (v006) of MODIS Terra and Aqua 8 day snow cover composites (MOD10A2/MYD10A2). We focused on three metrics of snow seasonality—first date of snow, last date of snow, and duration of snow season—and used nonparametric trends tests to assess the significance and direction of trends. We evaluated trends at three administration scales and across elevation. We used two techniques to assure that our identification of significant trends was …


Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry May 2018

Changing Snow Seasonality In The Highlands Of Kyrgyzstan, Monika Tomaszewska, Geoffrey Henebry

NASA Land-Cover Land-Use Change Data Sets

Few studies have examined changing snow seasonality in Central Asia. Here, we analyzed changes in the seasonality of snow cover across Kyrgyzstan (KGZ) over 14 years from 2002/03–2015/16 using the most recent version (v006) of MODIS Terra and Aqua 8 day snow cover composites (MOD10A2/MYD10A2).We focused on three metrics of snow seasonality—first date of snow, last date of snow, and duration of snow season—and used nonparametric trends tests to assess the significance and direction of trends. We evaluated trends at three administration scales and across elevation. We used two techniques to assure that our identification of significant trends was not …


An Assessment Of Atmospheric And Meteorological Factors Regulating Red Sea Phytoplankton Growth, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Emmanouil Proestakis, Michael J. Garay, Olga V. Kalishnikova, Vassilis Amiridis, Antonis Gkikas, Eleni Marinou, Thomas Piechota, K. P. Manikandan Apr 2018

An Assessment Of Atmospheric And Meteorological Factors Regulating Red Sea Phytoplankton Growth, Wenzhao Li, Hesham El-Askary, Mohamed A. Qurban, Emmanouil Proestakis, Michael J. Garay, Olga V. Kalishnikova, Vassilis Amiridis, Antonis Gkikas, Eleni Marinou, Thomas Piechota, K. P. Manikandan

Mathematics, Physics, and Computer Science Faculty Articles and Research

This study considers the various factors that regulate nutrients supply in the Red Sea. Multi-sensor observation and reanalysis datasets are used to examine the relationships among dust deposition, sea surface temperature (SST), and wind speed, as they may contribute to anomalous phytoplankton blooms, through time-series and correlation analyses. A positive correlation was found at 0–3 months lag between chlorophyll-a (Chl-a) anomalies and dust anomalies over the Red Sea regions. Dust deposition process was further examined with dust aerosols’ vertical distribution using satellite lidar data. Conversely, a negative correlation was found at 0–3 months lag between SST anomalies …


Investigation Of The Fire Radiative Energy Biomass Combustion Coefficient - A Comparison Of Polar And Geostationary Satellite Retrievals Over The Conterminous United States, Fangjun Li, Xiaoyang Zhang Feb 2018

Investigation Of The Fire Radiative Energy Biomass Combustion Coefficient - A Comparison Of Polar And Geostationary Satellite Retrievals Over The Conterminous United States, Fangjun Li, Xiaoyang Zhang

Global Land Surface Season Data Sets

The data is for the article "Investigation of the Fire Radiative Energy Biomass Combustion Coefficient - A Comparison of Polar and Geostationary Satellite Retrievals Over the Conterminous United States", which has been submitted to the Journal of Geophysical Research: Biogeosciences.

The data file contains a total of 20 files in 10 folders that are associated to the figures and tables in the article. General instruction for viewing output data for the paper can be found in the "Readme" text file.


Impact Of Drought On Land Cover Changes In Diné Bikéyah – A Study Through Remote Sensing, Anjanette A.J. Hawk Jan 2018

Impact Of Drought On Land Cover Changes In Diné Bikéyah – A Study Through Remote Sensing, Anjanette A.J. Hawk

Geography ETDs

This study identifies land cover changes associated with a ten-year drought period and discusses the importance of vegetation change in Diné Bikéyah, a semi-arid land located in a remote part of the southwestern United States (US). This study concludes that drought produced slight changes in vegetation within a 540 km2 study area in the Tselani-Cottonwood Chapter (TCC) in Diné Bikéyah. The data for this study consist of three Landsat images for the years 1998, 2002, and 2009. The methods used to analyze these Landsat images included image pre-processing, calculation of normalized difference vegetation index (NDVI) images, and supervised (maximum …


Expansion Of Major Urban Areas In The Us Great Plains From 2000 To 2009 Using Satellite Scatterometer Data, Lan H. Nguyen, Son V. Nghiem, Geoffrey M. Henebry Jan 2018

Expansion Of Major Urban Areas In The Us Great Plains From 2000 To 2009 Using Satellite Scatterometer Data, Lan H. Nguyen, Son V. Nghiem, Geoffrey M. Henebry

GSCE Faculty Publications

A consistent dataset delineating and characterizing changes in urban environments will be valuable for socioeconomic and environmental research and for sustainable urban development. Remotely sensed data have been long used to map urban extent and infrastructure at various spatial and spectral resolutions. Although many datasets and approaches have been tried, there is not yet a universal way to map urban extents across the world. Here we combined a microwave scatterometer (QuikSCAT) dataset at ~1 km posting with percent impervious surface area (%ISA) data from the National Land Cover Dataset (NLCD) that was generated from Landsat data, and ambient population data …


Utilizing Collocated Crop Growth Model Simulations To Train Agronomic Satellite Retrieval Algorithms, Nathaniel Levitan, Barry Gross Jan 2018

Utilizing Collocated Crop Growth Model Simulations To Train Agronomic Satellite Retrieval Algorithms, Nathaniel Levitan, Barry Gross

Publications and Research

Due to its worldwide coverage and high revisit time, satellite-based remote sensing provides the ability to monitor in-season crop state variables and yields globally. In this study, we presented a novel approach to training agronomic satellite retrieval algorithms by utilizing collocated crop growth model simulations and solar-reflective satellite measurements. Specifically, we showed that bidirectional long short-term memory networks (BLSTMs) can be trained to predict the in-season state variables and yields of Agricultural Production Systems sIMulator (APSIM) maize crop growth model simulations from collocated Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m satellite measurements over the United States Corn Belt at a regional …


Quantifying Undisturbed (Native) Lands In Northwestern South Dakota: 2013, Pete Bauman, Benjamin Carlson, Tanner Butler, Brad Richardson Jan 2018

Quantifying Undisturbed (Native) Lands In Northwestern South Dakota: 2013, Pete Bauman, Benjamin Carlson, Tanner Butler, Brad Richardson

Quantifying Undisturbed (Native) Lands in Northwestern South Dakota: 2013

We employed simple GIS methods primarily utilizing the South Dakota Farm Service Agency’s Common Land Unit (CLU) data layers from 2013 and the 2012 United States Department of Agriculture (USDA) National Agriculture Imagery Program (NAIP) county mosaic aerial imagery to evaluate 7,347,812 acres of land in northwestern South Dakota. The analysis area includes: Harding, Perkins, and Butte counties along with portions of Lawrence and Meade counties outside of the Black Hills Core Highlands and Plateau Ecoregions.

We utilized the FSA CLU data layer queried to show current and former cropland to identify and remove any areas with cropping history regardless …


Satellite Remote Sensing Of Woody And Herbaceous Leaf Area For Improved Understanding Of Forage Resources And Fire In Africa, Milkah Njoki Kahiu Jan 2018

Satellite Remote Sensing Of Woody And Herbaceous Leaf Area For Improved Understanding Of Forage Resources And Fire In Africa, Milkah Njoki Kahiu

Electronic Theses and Dissertations

In sub-Saharan Africa (SSA) tree-grass systems commonly referred to as savannas dominating drylands, play a critical role in social, cultural, economic and environmental systems. These coupled natural-human systems support millions of people through pastoralism, are important global biodiversity hotspots and play a critical role in global biogeochemical cycles. Despite the importance of SSA savannas, they have been marginalized for years as most governments neglect dryland resources in favor of agricultural research and development assistance. Hence, lack of spatially and temporally accurate information on the status and trends in savanna resources has led to poor planning and management. This scenario calls …


A Study Of African Savanna Vegetation Structure, Patterning, And Change, Christoffer R. Axelsson Jan 2018

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 Jan 2018

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 …


Accounting For Spatial Autocorrelation In Modeling The Distribution Of Water Quality Variables, Lorrayne Miralha Jan 2018

Accounting For Spatial Autocorrelation In Modeling The Distribution Of Water Quality Variables, Lorrayne Miralha

Theses and Dissertations--Geography

Several studies in hydrology have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this thesis, I hypothesized that SAC, inherently possessed by a response variable, influences spatial modeling outcomes. I selected ten watersheds in the USA and analyzed them to determine whether water quality variables with higher Moran’s I values undergo greater increases in the coefficient of determination (R²) and greater decreases in residual SAC (rSAC) after spatial modeling. I compared non-spatial ordinary …