Geography

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Start date: 2001End date: 2009

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    THE EFFECTS OF CHANGES IN LAND COVER AND LAND USE ON NUTRIENT LOADINGS TO THE CHESAPEAKE BAY USING FORECASTS OF URBANIZATION
    (2009) Roberts, Allen Derrick; Prince, Stephen D.; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This dissertation examined the effects of land cover and land use (LC/LU) change on nutrient loadings (mass for a specified time) to the Chesapeake Bay, after future projections of urbanization were applied. This was accomplished by quantifying the comprehensive impacts of landscape on nutrients throughout the watershed. In order to quantify forecasted impacts of future development and LC/LU change, the current (2000) effects of landscape composition and configuration on total nitrogen (TN) and total phosphorus (TP) were examined. The effects of cover types were examined not only at catchment scales, but within riparian stream buffer to quantify the effects of spatial arrangement. Using the SPAtially Referenced Regressions On Watershed Attributes (SPARROW) model, several compositional and configurational metrics at both scales were significantly correlated to nutrient genesis and transport and helped estimate loadings to the Chesapeake Bay with slightly better accuracy and precision. Remotely sensed forecasts of future (2030) urbanization were integrated into SPARROW using these metrics to project TN and TP loadings into the future. After estimation of these metrics and other LC/LU-based sources, it was found that overall nutrient transport to the Chesapeake Bay will decrease due to agricultural land losses and fertilizer reductions. Although point and non-point source urban loadings increased in the watershed, these gains were not enough to negate decreased agricultural impacts. In catchments forecasted to undergo urban sprawl conditions by 2030, the response of TN locally generated within catchments varied. The forecasted placement of smaller patches of development within agricultural lands of higher nutrient production was correlated to projected losses. However, shifting forecasted growth onto or adjacent to existing development, not agricultural lands, resulted in projected gains. This indicated the importance of forecasted spatial arrangement to projected TN runoff from the watershed. In conclusion, comprehensive landscape analysis resulted in differences in simulations of current and future nutrient loadings to the Chesapeake Bay, as a result of urbanization and LC/LU change. With eutrophication from excess nutrients being the primary challenge to the estuary, information gained from the estimation of these effects could improve the future management and regulation of the Chesapeake Bay.
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    SPATIAL AND SEASONAL DISTRIBUTION OF CARBON DIOXIDE EMISSIONS FROM FOSSIL-FUEL COMBUSTION; GLOBAL, REGIONAL, AND NATIONAL POTENTIAL FOR SUSTAINABLE BIOENERGY FROM RESIDUE BIOMASS AND MUNICIPAL SOLID WASTE
    (2009) Gregg, Jay Sterling; Dubayah, Ralph; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Combustion of fossil fuels releases carbon dioxide (CO2) into the atmosphere, and has led to an increase in the atmospheric concentration of CO2. CO2 is a greenhouse gas, and the increase in concentration leads to an increase in global temperatures and global climatic change. Fossil-fuel consumption, along with cement production, is responsible for 80% of anthropogenic carbon emissions and consumption of fossil fuels continues to increase. Despite its importance to the global climate and the global carbon cycle, data for fossil fuel CO2 emissions are traditionally maintained only on national levels and annual time steps. A method is developed to improve the spatiotemporal resolution to the leading energy consuming countries of the world. The method uses energy consumption datasets as well as other ancillary datasets to apportion national annual emissions totals into sub-national and monthly emissions datasets by fuel type. Emissions patterns are highly variable both temporally and spatially by fuel type, and detailed information on the distribution of emissions improves our understanding of the global carbon cycle and leads to better understanding of the spatial and seasonal distribution of the drivers of global change.
    In the endeavor to develop alternatives to fossil fuels, advanced biomass energy has garnered much attention because of its renewable nature and its potential to approach carbon-neutrality. As co-products, agricultural and forestry residues as well as municipal solid waste (MSW) are potential low-cost and sustainable biomass feedstocks for energy production. The role of residue biomass within the future global energy portfolio is projected and quantified under the context of environmental and economic sustainability. The potential for residue biomass is projected for the next century under a reference (business-as-usual) scenario and a scenario that includes a hypothetical climate policy that limits carbon emissions. While residue biomass alone cannot replace fossil fuels, a substantial amount of energy potentially could come from this resource, particularly in a global economic market under a climate policy that caps CO2 emissions from fossil fuels.
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    Improving Satellite Leaf Area Index Estimation Based On Various Integration Methods
    (2009) Wang, Dongdong; Liang, Shunlin; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Leaf Area Index (LAI) is an important land surface biophysical variable that is used to characterize vegetation amount and activity. Current satellite LAI products, however, do not satisfy the requirements of the modeling community due to their large uncertainties and frequent missing values. Each LAI product is currently generated from only one satellite sensor data. There is an urgent need for advanced methods to integrate multiple LAI products to improve the product's accuracy and integrality for various applications. To meet this need, this study proposes four methods, including the Optimal Interpolation (OI), Bayesian Maximum Entropy (BME), Multi-Resolution Tree (MRT) and Empirical Orthogonal Function (EOF), to integrate multiple LAI products. Three LAI products have been considered in this study: Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging SpectroRadiometer (MISR) and Carbon cYcle and Change in Land Observational Products from an Ensemble of Satellites (CYCLOPES) LAI. As the basis of data integration, this dissertation first validates and intercompares MODIS and CYCLOPES LAI products and also evaluates their geometric accuracies. The CYCLOPES LAI product has smoother temporal profiles and fewer spatial variations, but tends to produce spurious large errors in winter. The Locally Adjusted Cubic-spline Capping algorithm is revised to smooth multiple years' average and variance. Although OI, BME and MRT based methods have been used in other fields, this is the first research to employ them in integrating multiple LAI products. This dissertation also presents a new integration method based on EOF to solve the problem of large data volume and inconsistent temporal resolution of different datasets. High resolution LAI reference maps generated with ground measurements are used to validate these algorithms. Validation results show that all of these four methods can fill data gaps and reduce the errors of the existing LAI products. The data gaps are filled with information from adjacent pixels and background. These algorithms remove the spurious large temporal and spatial variation of the original LAI products. The combination of multiple satellite products significantly reduces bias. OI and BME can reduce the RMSE from 1.0 (MODIS) to 0.7 and reduce the bias from +0.3 (MODIS) and -0.2 (CYCLOPES) to -0.1. MRT can produce similar results with OI but with significantly improved efficiency. EOF also generates the results with the RMSE of 0.7 but zero bias. Limited ground measurement data hardly prove which methods outperform the others. OI and BME theoretically produce statistically optimal results. BME relaxes OI's linear and Gaussian assumption and explicitly considers data error, but bears a much higher computational burden. MRT has improved efficiency but needs strict assumptions on the scale transfer function. EOF requires simpler model identification, while it is more "empirical" than "statistical". The original contributions of this study mainly include: 1) a new application of several different integration methods to incorporate multiple satellite LAI products to reduce uncertainties and improve integrality, 2) an enhancement of the Locally Adjusted Cubic-spline Capping by revising the end condition, 3) a novel comprehensive comparison of MODIS C5 LAI product with other satellite products, 4) the development of a new LAI normalization scheme by assuming the linear relationship between measurement error and LAI natural variance to account for the inconsistency between products, and finally, 5) the creation of a new data integration method based on EOF.
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    AN APPROACH TO ESTIMATE GLOBAL BIOMASS BURNING EMISSIONS OF ORGANIC AND BLACK CARBON FROM MODIS FIRE RADIATIVE POWER
    (2009) Ellicott, Evan Andrew; Justice, Christopher O; Vermote, Eric; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Biomass burning is an important global phenomenon affecting atmospheric composition with significant implications for climatic forcing. Wildland fire is the main global source of fine primary carbonaceous aerosols in the form of organic carbon (OC) and black carbon (BC), but uncertainty in aerosol emission estimates from biomass burning is still rather large. Application of satellite based measures of fire radiative power (FRP) has been demonstrated to offer an alternative approach to estimate biomass consumed with the potential to estimate the associated emissions from fires. To date, though, no study has derived integrated FRP (referred to as fire radiative energy or FRE) at a global scale, in part due to limitations in temporal or spatial resolution of satellite sensors. The main objective of this research was to quantify global biomass burning emissions of organic and black carbon aerosols and the corresponding effect on planetary radiative forcing. The approach is based on the geophysical relationship between the flux of FRE emitted, biomass consumed, and aerosol emissions. Aqua and Terra MODIS observations were used to estimate FRE using a simple model to parameterize the fire diurnal cycle based on the long term ratio between Terra and Aqua MODIS FRP and cases of diurnal satellite measurements of FRP made by the geostationary sensor SEVIRI, precessing sensor VIRS, and high latitude (and thus high overpass frequency) observations by MODIS. Investigation of the atmospheric attenuation of MODIS channels using a parametric model based on the MODTRAN radiative transfer model indicates a small bias in FRE estimates which was accounted for. Accuracy assessment shows that the FRE estimates are precise (R2 = 0.85), but may be underestimated. Global estimates of FRE show that Africa and South America dominate biomass burning, accounting for nearly 70% of the annual FRE generated. The relationship between FRE and OCBC estimates made with a new MODIS-derived inversion product of daily integrated biomass burning aerosol emissions was explored. The slope of the relationship within each of several biomes yielded a FRE-based emission factor. The biome specific emission factors and FRE monthly data were used to estimate OCBC emissions from fires on a global basis for 2001 to 2007. The annual average was 17.23 Tg which was comparable to previously published values, but slightly lower. The result in terms of global radiative forcing suggests a cooling effect at both the top-of-atmosphere (TOA) and surface approaching almost -0.5 K which implies that biomass burning aerosols could dampen the warming effect of green house gas emissions. An error budget was developed to explore the sources and total uncertainty in the OCBC estimation. The results yielded an uncertainty value of 58% with specific components of the process warranting future consideration and improvement. The uncertainty estimate does not demonstrate a significant improvement over current methods to estimate biomass burning aerosols, but given the simplicity of the approach should allow for refinements to be made with relative ease.
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    The Changing Spatial Distribution of the Population of the Former Soviet Union
    (2009) Heleniak, Timothy Edmund; Geores, Martha E; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    When it existed, the Soviet Union was a closed economic and migration space with tightly-controlled movement of goods, people, and ideas across its borders. It was also an ethnically complex region with 130 different nationalities, fifty-three with territorially-based ethnic homelands, of which fifteen became the successor states to the Soviet Union. The breakup of the Soviet Union, the transition towards market economies, and the liberalization of the societies have together greatly impacted the lives of people in the region. Many found themselves in countries or regions with dramatically shrunken economies or as ethnic minorities in newly independent states and many have chosen migration as a strategy of adaptation to the new circumstances in which they found themselves. Using established migration theory, this dissertation examines the causes of migration among the fifteen successor states since 1991. The main test was to compare the relative impact of economic factors versus ethnic factors driving migration movements in the post-Soviet space. The results showed that while some of the movements could be classified as people migrating to their ethnic homelands, a majority could be explained by neoclassical economic theories of migration and the large income differentials that have resulted from the economic transition. Other theories that have been found to explain migration in other world migration systems were found to also be applicable in the former Soviet Union.
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    Using a Socio-Cultural Framework to Evaluate Farmland Preservation Policy Success in Maryland
    (2009) Russo, Richard Anthony; Geores, Martha E; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The intent of Maryland's farmland preservation policy has remained constant over the past three decades -- to preserve productive farmland and woodland for the continued production of food and fiber for all of Maryland's citizens. Therefore, thirty years after this statutory goal was made, how effective have Maryland's farmland preservation programs been in reaching this goal? This study addresses the absence of cultural and social analysis in the evaluation of farmland preservation program success in Maryland's metropolitan counties. In utilizing a socio-cultural framework of analysis, this study shows that farmland preservation policies (in their drafting, implementation, and evaluation) are a cultural process, the outcomes of which create and sustain a particular social space and cultural landscape. Theories on the social production of space and landscape are relevant to the task of farmland preservation and agricultural economic development in metropolitan areas. The failure of farmland preservation policy in Maryland has, in part, been the failure to take culture seriously. Quantitative indicators show that Maryland's state farmland preservation program has achieved moderate success in securing a productive agricultural land base over its first three decades, but has not been successful in preserving farming as a viable "way of life," has not stopped the erosion in the value of agricultural sales, and has not reversed the marketplace alienation between producers and consumers in the state.
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    Socio-demographic Variables as Risk Factors for Neurologic Disease due to Infection by West Nile Virus
    (2009) Pugh, Lashale D.; Kearney, Michael; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The primary question asked by this research was "Can socio-demographic characteristics be considered risk factors for neurological disease due to West Nile Virus?" Based on the results of this research, the answer is yes. Socio-demographic characteristics identified as risk factors are related to educational attainment, income, age of housing and poverty. Socio-economic variables were useful in discriminating between high moderate and low infection rates and showed modest capabilities of estimating actual rates. One of the most important findings of the research was the public health officials own ideas about the greatest obstacle to preventing the spread of WNV in their jurisdictions. General consensus is that more resources be made available to properly combat this pathogen. More staff and funds to pay workers and provide support for every aspect of surveillance, prevention and control are deemed necessary. Specifically, there is a great need for personnel with specialized training. The support and encouragement of public health organizations is needed to attract individuals into academic fields that will prepare them for infectious disease epidemiology which is crucial to the field. Local level response may have been dictated by resource availability as opposed to the perceived threat. Surprisingly, length of time in the current position was more closely related to lower infection rates than length of surveillance. This suggests that more experienced public health workers likely have some knowledge or experience which was not made known through the survey. Policy implications suggest increased education for public health officials, especially encouragement of more experienced workers to share their knowledge and experiences with less experienced workers.
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    SEASONAL AND INTERANNUAL VARIABILITY OF EMISSIONS FROM CROP RESIDUE BURNING IN THE CONTIGUOUS UNITED STATES
    (2009) McCarty, Jessica; Justice, Chrisopher O; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Crop residue burning is a global agricultural practice used to remove excess residues before or after harvest. Crop residue burning in the contiguous United States (CONUS) has been documented at the regional and state-level by governmental organizations and in the scientific literature. Emissions from crop residue burning in the CONUS have been found to impair local and regional air quality, leading to serious health impacts and legal disputes. Currently, there is no baseline estimate for the area and emissions of crop residue burning in the CONUS. A bottom-up model for emissions calculations is employed to calculate CO2, CO, CH4, NO2, SO2, PM2.5, PM10, and Pb emissions from crop residue burning in the CONUS for the years 2003 through 2007. These atmospheric species have negative impacts on air quality and human health and are important to the carbon cycle. Spatially and temporally explicit cropland burned area and crop type products for the CONUS, necessary for emissions calculations, are developed using remote sensing approaches. The majority of crop residue burning and emissions in the CONUS are shown to occur during the spring (April - June) and fall harvests (October - December). On average, 1,239,000 ha of croplands burn annually in the CONUS with an average interannual variability of ± 91,200 ha. In general, CONUS crop residue burning emissions vary less than ±10% interannually. The states of Arkansas, California, Florida, Idaho, Texas, and Washington emit 50% of PM10, 51% of CO2, 52% of CO, and 63% of PM2.5 from all crop residue burning in the CONUS. Florida alone emits 17% of all annual CO2, CO, and PM2.5 emissions and 12% of annual PM10 emissions from crop residue burning. Crop residue burning emissions in the CONUS account for as little as 1% of global agricultural emissions and as much as 15% of all agricultural burning emissions estimates in North America, including Mexico and Canada. The results have implications for international, federal, and state-level reporting and monitoring of air quality and greenhouse gas and carbon emissions aimed at protecting human health, mitigating climate change, and understanding the carbon cycle.
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    Transforming Espacios Culturales into Cultural Spaces: How the Salvadoran Community is Establishing Evangelical Protestan Churches as Transtional Institutions in the Washington D.C. Metropolitan Area
    (2008-12-04) Luna, Ronald W; Geores, Martha; Townshend, John; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Transnationalism is a theoretical concept that explains the current migration patterns that are in stark contrast to the prevailing theories of Acculturation and Assimilation. Migration can no longer be described as a linear process. Transnational "migrants" have a foot in both worlds. No matter where their legal citizenship lies, they have a dual social citizenship. Transnationalism is used not just to identify how immigrants maintain their culture in the host country but just as importantly, how they establish and maintain social and economic linkages between both countries. Transnationalism lacks a cohesive definition and a way to test whether it is present. The Salvadoran Evangelical Protestant Churches in the Washington D.C. Metropolitan Area serves as case study to examine how the transnationalism process occurs. Key findings include understanding first how transnational communities are established in the host country, as well as how transnational institutions such as Salvadoran Evangelical Protestant Churches began their process of transnationalism in the home country. Furthermore, the Salvadoran Evangelical Protestant Churches reflect and parallel the overall transnational Salvadoran historical and demographic trends. In addition, Salvadoran Evangelical Protestant Churches reinforce the process of transnationalism in the Washington D.C. Metropolitan Area through memory, ethnic identity, transmigration, networks, and cultural space. It is important to understand that ethnic churches are a major facilitator of transnationalism in the host country; however, there are many other transnational institutions that reinforce the process of transnationalism. This study examines independently each element, which contributes to the process of transnationalism: memory, ethnic identity, transmigration, networks, and cultural space. The research concludes by redefining transnationalism as the process that by which transmigrants create economic, political, social, or cultural networks by participating directly or indirectly in transmigration. Furthermore, transnationalism refers to the process by which migrants become transnational agents when they create linkages at various scales, over time, and across space between the host and home countries and vice versa.
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    Changes in Amazon Forest Structure from Land-Use Fires: Integrating Satellite Remote Sensing and Ecosystem Modeling
    (2008-11-17) Morton, Douglas; DeFries, Ruth S; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Fire is the dominant method of deforestation and agricultural maintenance in Amazonia, and these land-use fires frequently escape their intended boundaries and burn into adjacent forests. Initial understory fires may increase forest flammability, thereby creating a positive fire feedback and the potential for long-term changes in Amazon forest structure. The four studies in this dissertation describe the development and integration of satellite remote sensing and ecosystem modeling approaches to characterize land-use fires and their consequences in southern Amazon forests. The dissertation contributes three new methods: use of the local frequency of satellite-based active fire detections to distinguish between deforestation and maintenance fires, use of satellite data time series to identify canopy damage from understory fires, and development of a height-structured fire sub-model in Ecosystem Demography, an advanced ecosystem model, to evaluate the impacts of a positive fire feedback on forest structure and composition. Conclusions from the dissertation demonstrate that the expansion of mechanized agricultural production in southern Amazonia increased the frequency and duration of fire use compared to less intensive methods of deforestation for pasture. Based on this increase in the frequency of land-use fires, fire emissions from current deforestation may be higher than estimated for previous decades. Canopy damage from understory fires was widespread in both dry and wet years, suggesting that drought conditions may not be necessary to burn extensive areas of southern Amazon forests. Understory fires were five times more common in previously-burned than unburned forest, providing satellite-based evidence for a positive fire feedback in southern Amazonia. The impact of this positive fire feedback on forest structure and composition was assessed using the Ecosystem Demography model. Scenarios of continued understory fires under current climate conditions show the potential to trap forests in a fire-prone structure dominated by early-successional trees, similar to secondary forests, reducing net carbon storage by 20-46% within 100 years. In summary, satellite and model-based results from the dissertation demonstrate that fire-damaged forests are an extensive and long-term component of the frontier landscape in southern Amazonia and suggest that a positive fire feedback could maintain long-term changes in forest structure and composition in the region.