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Articles 31 - 50 of 50

Full-Text Articles in Physical and Environmental Geography

Greening Of The Arctic: Plot-Scale Analysis Of Interactions Between Climate, Vegetation, And Permafrost At Toolik Lake, Alaska (1995 - 2017), Brianna Rick Jan 2018

Greening Of The Arctic: Plot-Scale Analysis Of Interactions Between Climate, Vegetation, And Permafrost At Toolik Lake, Alaska (1995 - 2017), Brianna Rick

Graduate Student Theses, Dissertations, & Professional Papers

Air temperatures across the Arctic have increased in recent decades, and through complex feedbacks, vegetation and permafrost (frozen ground) are actively responding as climate warming continues. This study investigates the trends and interactions of observed air, soil-surface temperature (SST), and active-layer thickness (ALT) at Toolik Lake on the Alaskan North Slope between 1995 and 2017, as well as vegetation change over time.

Time series between 1995 and 2017 at CALM site U12B, a 1 ha plot near Toolik Lake, reveal an increase (0.50 °C/decade) in mean summer (Jun-Aug) air temperatures and a decrease (­0.23 °C/decade) in mean summer SST. In …


Utilizing A Consumer-Grade Camera System To Quantify Surface Reflectance, Joseph J. Lehnert Aug 2017

Utilizing A Consumer-Grade Camera System To Quantify Surface Reflectance, Joseph J. Lehnert

Department of Geography: Dissertations, Theses, and Student Research

Consumer-grade camera systems are often employed in aerial remote sensing to provide insight into patterns and processes of interest to science and industry, a trend that has largely been encouraged by the rapid growth of the small unmanned aircraft system (sUAS) industry. However, little research exists on the ability of these systems to accurately measure surface reflectance in specific wavebands, a crucial consideration for many remote sensing applications. This research was conducted on the premise that with proper equipment and calibration techniques consumer-grade cameras would be capable of accurately measuring surface reflectance in user-defined wavebands of interest. A stereo-pair, Fujifilm …


Integrating Malaria Surveillance With Climate Data For Outbreak Detection And Forecasting: The Epidemia System, Christopher L. Merkord, Yi Liu, Abere Mihretie, Teklehaymanot Gebrehiwot, Worku Awoke, Estifanos Bayabil, Geoffrey M. Henebry, Gebeyaw T. Kassa, Mastewal Lake, Michael C. Wimberly Feb 2017

Integrating Malaria Surveillance With Climate Data For Outbreak Detection And Forecasting: The Epidemia System, Christopher L. Merkord, Yi Liu, Abere Mihretie, Teklehaymanot Gebrehiwot, Worku Awoke, Estifanos Bayabil, Geoffrey M. Henebry, Gebeyaw T. Kassa, Mastewal Lake, Michael C. Wimberly

GSCE Faculty Publications

Background: Early indication of an emerging malaria epidemic can provide an opportunity for proactive interventions. Challenges to the identification of nascent malaria epidemics include obtaining recent epidemiological surveillance data, spatially and temporally harmonizing this information with timely data on environmental precursors, applying models for early detection and early warning, and communicating results to public health officials. Automated web-based informatics systems can provide a solution to these problems, but their implementation in real-world settings has been limited.
Methods: The Epidemic Prognosis Incorporating Disease and Environmental Monitoring for Integrated Assessment (EPIDEMIA) computer system was designed and implemented to integrate disease surveillance with …


Multi-Year Modis Active Fire Type Classification Over The Brazilian Tropical Moist Forest Biome, David P. Roy, S. S. Kumar Jan 2017

Multi-Year Modis Active Fire Type Classification Over The Brazilian Tropical Moist Forest Biome, David P. Roy, S. S. Kumar

GSCE Faculty Publications

The Brazilian Tropical Moist Forest Biome (BTMFB) spans almost 4 million km2 and is subject to extensive annual fires that have been categorized into deforestation, maintenance, and forest fire types. Information on fire types is important as they have different atmospheric emissions and ecological impacts. A supervised classification methodology is presented to classify the fire type of MODerate resolution Imaging Spectroradiometer (MODIS) active fire detections using training data defined by consideration of Brazilian government forest monitoring program annual land cover maps, and using predictor variables concerned with fuel flammability, fuel load, fire behavior, fire seasonality, fire annual frequency, proximity …


An Integrated Approach For A Better Understanding Of The Paleo-Hydrology And Landscape Evolution In The Sahara During The Previous Wet Climatic Periods, Abotalib Zaki Abotalib Farag Dec 2016

An Integrated Approach For A Better Understanding Of The Paleo-Hydrology And Landscape Evolution In The Sahara During The Previous Wet Climatic Periods, Abotalib Zaki Abotalib Farag

Dissertations

Paleoclimatic regimes over Saharan Africa alternated between dry and wet periods throughout the Pleistocene Epoch, and it is during the wet periods that the Saharan fossil aquifers were recharged. The present study investigates the role of groundwater-related processes in shaping the Saharan landforms (e.g., theater-headed valleys [THV]; depressions, escarpments, playas, and tufa deposits) over areas occupied by the largest of these aquifer systems, the Nubian Sandstone Aquifer System (NSAS). The present study reviews the suggested hypotheses for the origin of these landforms in the Sahara, and in similar settings elsewhere, and presents evidence in support of the following: during the …


Land Cover Data For The Mississippi-Alabama Barrier Islands, 2010-2011 Arcgis V10.3 Geodatabase, Gregory A. Carter, Carlton P. Anderson, Kelly L. Lucas, Nathan L. Hopper Jul 2016

Land Cover Data For The Mississippi-Alabama Barrier Islands, 2010-2011 Arcgis V10.3 Geodatabase, Gregory A. Carter, Carlton P. Anderson, Kelly L. Lucas, Nathan L. Hopper

Land Cover Data for the Mississippi-Alabama Barrier Islands, 2010-2011

Land cover on the Mississippi-Alabama barrier islands was surveyed in 2010-2011 as part of continuing research on island geomorphic and vegetation dynamics following the 2005 impact of Hurricane Katrina. Results of the survey include sub-meter GPS location, a listing of dominant vegetation species and field photographs recorded at 375 sampling locations distributed among Cat, West Ship, East Ship, Horn, Sand, Petit Bois and West Dauphin Islands. The survey was conducted in a period of intensive remote sensing data acquisition over the northern Gulf of Mexico by federal, state and commercial organizations in response to the 2010 Macondo Well (Deepwater Horizon) …


Simulating The Impacts Of Land-Use Land-Cover Changes On Cropland Carbon Fluxes In The Midwest Of The United States, Zhengpeng Li Jan 2016

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 …


A Vegetation Analysis On Horn Island, Mississippi, Ca. 1940 Using Characteristic Dimensions Derived From Historical Aerial Photography, Guy Wilburn Jeter Jr. Dec 2014

A Vegetation Analysis On Horn Island, Mississippi, Ca. 1940 Using Characteristic Dimensions Derived From Historical Aerial Photography, Guy Wilburn Jeter Jr.

Master's Theses

Horn Island is part of the MS/AL barrier island chain in the northern Gulf of Mexico located approximately 18kn off the coast of Mississippi. This island’s habitats have undergone many transitions over the last several decades. The goal of this study was to quantify habitat change over a seventy year period using historical black and white photography from 1940. Using present NAIP imagery from the USDA, habitat structure was estimated by using geo-statistics, and second order statistics, from a co-occurrence matrix, to characterize texture for habitat classification. Percent land cover was then calculated to determine overall land cover change over …


Integrated (Remote Sensing, Gis, And Modeling) Hydrological Investigation And Landslide Susceptibility Studies In The Arabian Shield, Talal Ghazi Alharbi Aug 2014

Integrated (Remote Sensing, Gis, And Modeling) Hydrological Investigation And Landslide Susceptibility Studies In The Arabian Shield, Talal Ghazi Alharbi

Dissertations

An integrated approach (remote sensing, geographical information systems [GIS], and modeling) was applied to conduct a number of hydrologic and environmental investigations in the Arabian Peninsula (AP) aimed at: (1) identifying the spatial and temporal climate change–related variations in precipitation over the AP using readily available, remotely acquired global precipitation data sets; (2) investigating the nature of the factors controlling the observed climatic variations; (3) estimating the partitioning of precipitation over the Red Sea Hills watersheds into runoff , recharge, and initial losses using calibrated continuous rainfall runoff models (Soil Water Assessment Tool [SWAT]); (4) identifying landslide (largely caused by …


Predictive Modeling In The Search For Vertebrate Fossils: Geographic Object Based Image Analysis (Geobia) In The Eocene Of Wyoming, Bryan Bommersbach Jun 2014

Predictive Modeling In The Search For Vertebrate Fossils: Geographic Object Based Image Analysis (Geobia) In The Eocene Of Wyoming, Bryan Bommersbach

Masters Theses

The development and testing of predictive models for identifying productive fossil localities represents a promising interdisciplinary endeavor among geographic information scientists, paleoanthropologists, and vertebrate paleontologists. This thesis analyzed high resolution (2m spatial resolution) commercial satellite imagery from the Worldview-2 satellite of five areas of the Great Divide Basin using a GEographic Object-Based Image Analysis (GEOBIA) technique, which segments the image into spectrally homogeneous, multi-pixel image objects. In addition to allowing statistical analysis of the spectral characteristics of the image objects, GEOBIA techniques also let analysts incorporate expert knowledge and contextual information to improve classification accuracy. The spectral characteristics of the …


Interannual Variations And Trends In Global Land Surface Phenology Derived From Enhanced Vegetation Index During 1982–2010, Xiaoyang Zhang, Bin Tan, Yunyue Yu May 2014

Interannual Variations And Trends In Global Land Surface Phenology Derived From Enhanced Vegetation Index During 1982–2010, Xiaoyang Zhang, Bin Tan, Yunyue Yu

GSCE Faculty Publications

Land surface phenology is widely retrieved from satellite observations at regional and global scales, and its long-term record has been demonstrated to be a valuable tool for reconstructing past climate variations, monitoring the dynamics of terrestrial ecosystems in response to climate impacts, and predicting biological responses to future climate scenarios. This study detected global land surface phenology from the advanced very high resolution radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) data from 1982 to 2010. Based on daily enhanced vegetation index at a spatial resolution of 0.05 degrees, we simulated the seasonal vegetative trajectory for each individual pixel …


Validation Of Satellite Rainfall Products For Western Uganda., Jeremy E. Diem, Joel N. Hartter, Sadie J. Ryan, Michael W. Palace May 2014

Validation Of Satellite Rainfall Products For Western Uganda., Jeremy E. Diem, Joel N. Hartter, Sadie J. Ryan, Michael W. Palace

Geography

Central equatorial Africa is deficient in long-term, ground-based measurements of rainfall; therefore, the aim of this study is to assess the accuracy of three high-resolution, satellite-based rainfall products in western Uganda for the 2001–10 period. The three products are African Rainfall Climatology, version 2 (ARC2); African Rainfall Estimation Algorithm, version 2 (RFE2); and 3B42 from the Tropical Rainfall Measuring Mission, version 7 (i.e., 3B42v7). Daily rainfall totals from six gauges were used to assess the accuracy of satellite-based rainfall estimates of rainfall days, daily rainfall totals, 10-day rainfall totals, monthly rainfall totals, and seasonal rainfall totals. The northern stations had …


Proximal Sensing As A Means Of Characterizing Phragmites Australis, Travis Yeik Feb 2013

Proximal Sensing As A Means Of Characterizing Phragmites Australis, Travis Yeik

Department of Geography: Dissertations, Theses, and Student Research

Phragmites australis is an invasive wetland weed found throughout much of the United States. Documenting and mapping the growth and spread of this emergent macrophyte can be an important step in developing and implementing successful management strategies. Characterizing the phenology of a vegetation species with a sensor capable of hyperspectral resolution, positioned at close proximity to the canopy of interest, is often a first step necessary for understanding the basic species-specific reflectance patterns, and for quantifying the manner in which light interacts with the plants comprising particular communities. Spectral data over a P. australis canopy were collected during 22 …


Landscape Configuration And Urban Heat Island Effects: Assessing The Relationship Between Landscape Characteristics And Land Surface Temperature In Phoenix, Arizona, John Patrick Connors, Christopher S. Galletti, Winston T. L. Chow Feb 2013

Landscape Configuration And Urban Heat Island Effects: Assessing The Relationship Between Landscape Characteristics And Land Surface Temperature In Phoenix, Arizona, John Patrick Connors, Christopher S. Galletti, Winston T. L. Chow

Research Collection School of Social Sciences

The structure of urban environments is known to alter local climate, in part due to changes in land cover. A growing subset of research focuses specifically on the UHI in terms of land surface temperature by using data from remote sensing platforms. Past research has established a clear relationship between land surface temperature and the proportional area of land covers, but less research has specifically examined the effects of the spatial patterns of these covers. This research considers the rapidly growing City of Phoenix, Arizona in the United States. To better understand how landscape structure affects local climate, we explored …


Remote Sensing-Based Time Series Models For Malaria Early Warning In The Highlands Of Ethiopia, A. Midekisa, G. Senay, G. M. Henebry, P. Semuniguse, M. C. Wimberly May 2012

Remote Sensing-Based Time Series Models For Malaria Early Warning In The Highlands Of Ethiopia, A. Midekisa, G. Senay, G. M. Henebry, P. Semuniguse, M. C. Wimberly

Natural Resource Management Faculty Publications

Background

Malaria is one of the leading public health problems in most of sub-Saharan Africa, particularly in Ethiopia. Almost all demographic groups are at risk of malaria because of seasonal and unstable transmission of the disease. Therefore, there is a need to develop malaria early-warning systems to enhance public health decision making for control and prevention of malaria epidemics. Data from orbiting earth-observing sensors can monitor environmental risk factors that trigger malaria epidemics. Remotely sensed environmental indicators were used to examine the influences of climatic and environmental variability on temporal patterns of malaria cases in the Amhara region of Ethiopia. …


Prospects For An International Charter "Space And Major Disaster" Remote Sensing Response To Drought Disasters - An Anhui, China Case Study, Joseph Burkhead Apr 2012

Prospects For An International Charter "Space And Major Disaster" Remote Sensing Response To Drought Disasters - An Anhui, China Case Study, Joseph Burkhead

Masters Theses

Remote sensing is often leveraged during the response phase of disaster management to improve the situational awareness of decision-makers. The International Charter "Space and Major Disaster" (Charter) provides remote sensing support to non-spacefaring nations facing disasters such as earthquakes, floods and tsunamis. However, the Charter has never activated for a major drought disaster. Since droughts affect over half of the nearly 3 billion people that suffer from natural disasters annually, this study seeks to determine whether satellite remote sensing can be effectively employed according to the intent, capabilities, and limitations of the Charter to benefit officials responding to a major …


Assessing Seasonal Features Of Tropical Forests Using Remote Sensing, Roberto Bonifaz-Alfonzo May 2011

Assessing Seasonal Features Of Tropical Forests Using Remote Sensing, Roberto Bonifaz-Alfonzo

Department of Geography: Dissertations, Theses, and Student Research

Tropical forests are key components of the biogeochemical cycles, complex in structure, diversity and dynamics, also, tropical regions have been deforested and modified by human activities particularly for agriculture. Understanding the inter-annual and intra-annual variation dynamics of tropical regions could give valuable information on temporal characteristics of ecosystems behavior which is important for mapping and monitoring. This dissertation assesses seasonal and inter-annual changes in the tropical land cover that may be related to changes in the natural environment and/or human activities. Research was focused on the Mayan forest located in southern Mexico and Northwest Guatemala, one of the northern-most important …


Abstracting Gis Layers From Hyperspectral Imagery, Torsten E. Howard Mar 2009

Abstracting Gis Layers From Hyperspectral Imagery, Torsten E. Howard

Theses and Dissertations

Modern warfare methods in the urban environment necessitates the use of multiple layers of sensors to manage the battle space. Hyperspectral imagers are one possible sensor modality to provide remotely sensed images that can be converted into Geographic Information Systems (GIS) layers. GIS layers abstract knowledge of roads, buildings, and scene content and contain shape files that outline and highlight scene features. Creating shape files is a labor-intensive and time-consuming process. The availability of shape files that reflect the current configuration of an area of interest significantly enhances Intelligence Preparation of the Battlespace (IPB). The solution presented in this thesis …


Comparing Twenty-Four Years Of Forest Change In Two Communities Of Mexico's Meseta PuréPecha Using Multi-Spectral Satellite Imagery, Kevin Scott Martin Jun 2004

Comparing Twenty-Four Years Of Forest Change In Two Communities Of Mexico's Meseta PuréPecha Using Multi-Spectral Satellite Imagery, Kevin Scott Martin

Dissertations and Theses

The Meseta Purépecha, a volcanic plateau in the Mexican state of Michoacan, is home to one of the most species-rich pine forests in the world. Recent increases in demand for forest products has put added pressure on these resources. Though existing research has suggested significant deforestation in the Meseta, there is little information identifying specific areas of decline. This study focuses on two indigenous communities in the Meseta--Pichátaro and Sevina. Both communities have long relied on wood as an economic resource. However, the two communities have reacted differently to increased demand for forest resources. The purpose of this study is …


Satellite Remote Sensing For Measuring The Urban Forest Of Portland, Oregon, A. Paul Newman Sep 1997

Satellite Remote Sensing For Measuring The Urban Forest Of Portland, Oregon, A. Paul Newman

Dissertations and Theses

Digital pattern recognition methods were used to produce two maps of urban vegetation from LANDSAT Thematic Mapper for the City of Portland, Oregon. The image was acquired on July 7, 1991 and the spectral bands used were 2, 4, 5 and a ratio of 3 and 4. The two maps represent vegetation amount and vegetation type.

Due to the extreme heterogeneous nature of the urban environment, these maps were developed using techniques to reduce and manage the amount of spectral variation. This included purging non-vegetated cells from the multispectral image, and then stratifying the image into "spectral subdivisions" using tools …