My research interests are in the field of hydrology and land cover change science. More specifically, I am interested in applying remote sensing technologies to understand changes in the water cycle components and land cover. My current research focuses on the development of a remote sensing based water cycle information system focused on the Southwestern USA and northern Mexico, and integration of different remote sensing, ground-based and model-based products for water cycle analysis.
West Africa is one of the fastest growing regions of the world and depends heavily on rain-fed ag... more West Africa is one of the fastest growing regions of the world and depends heavily on rain-fed agriculture for its food production. This study evaluates 12 freely available land-cover and land-use (LCLU) data sets at the ecoregion, country, and pixel levels in West Africa to estimate croplands. The selected data sets are primarily derived using remote-sensing data, representing different time periods and using various classification schemes. The result shows a very high variability of the estimated cropland at all levels. Despite this variability, data sets having a finer spatial resolution and representing a similar time period – specifically data from the International Institute for Applied Systems Analysis-International Food Policy Research Institute (IIASA−IFPRI), Global Land Cover−Share (GLC−Share), Moderate Resolution Imaging Spectroradiometer–University of Maryland (MODIS−UMD), Global Cropland Extent, Moderate Resolution Imaging Spectroradiometer−International Geosphere Biosphere Programme (MODIS−IGBP), and GlobCover version 2.3 (GlobCover V23) – estimated comparable cropland areas at the ecoregion and country levels. The countrywide cropland area, obtained from the selected data sets, when compared with the sum of arable land and permanent crop area obtained from the Food and Agriculture Organization (FAO), showed a high coefficient of determination (R2 > 0.95) for IIASA–IFPRI and GLC−Share. At the pixel level, at the original resolution, the newer data sets have a comparable user’s accuracy (UA>53%) and producer’s accuracy (PA>46%), except for the Global Cropland Extent data. Overall, two data sets – IIASA−IFPRI and GLC−Share – performed better in the region to estimate the cropland area at all levels.
A global digitized inventory of floods is needed for assessing the spatial distribution and tempo... more A global digitized inventory of floods is needed for assessing the spatial distribution and temporal trends of flood hazards and for evaluating flood prediction models. This study describes the development of a global flood catalog compiled from news reports, scholarly articles, remote sensing images, and other natural hazard databases. The events cataloged in the inventory include information on the geographic location, date, duration, affected population, information source, and a qualitative measure of the event's magnitude and location accuracy. To minimize biases we cross-checked the catalog with different sources and eliminated any redundancies. This research presents the compilation methodology used to develop a digitized Global Flood Inventory (GFI) for the period 1998-2008. This global flood inventory differs from other flood catalogs by providing a publicly available spreadsheet that details all events with both descriptive and digitized information. This inventory has been proven useful for mapping natural hazards over the globe and for evaluating flood prediction model. This global flood inventory research compliments our companion catalog: global landslide hazards.
ABSTRACT Changes in the patterns, means, and extremes of precipitation affect the spatiotemporal ... more ABSTRACT Changes in the patterns, means, and extremes of precipitation affect the spatiotemporal distribution and magnitude of floods. Availability of satellite precipitation products from TRMM-based Multi-satellite Precipitation Analysis (TMPA) since 1998 motivated this study to assess the distribution of floods on a global basis. First, a digitized Global Flood Inventory (GFI) for the period of 1998-2008 has been developed from multiple sources. The GFI was used to evaluate retrospective simulations from NASA’s Global Flood Modeling (GFM) system, driven by TMPA and other meteorological forcing data. The evaluation is based on four different strategies: a) rainfall threshold, b) excess rainfall generated from a hydrological model, c) routed excess rainfall, and d) grid-based return period analysis of routed excess rainfall from c. Analysis of the results shows that the strategy based on the return periods of routed excess rainfall in d has the highest probability of detection while maintaining relatively low false alarm rates. Finally, both the observed GFI and simulated GFM results were used to map spatial patterns and temporal trends of global floods over the past decade.
This study aims to examine how future climate, temperature and precipitation specifically, are ex... more This study aims to examine how future climate, temperature and precipitation specifically, are expected to change under the A2, A1B, and B1 emission scenarios over the six states that make up the Southern Climate Impacts Planning Program (SCIPP): Oklahoma, Texas, Arkansas, Louisiana, Tennessee, and Mississippi. SCIPP is a member of the National Oceanic and Atmospheric Administration-funded Regional Integrated Sciences and Assessments network, a program which aims to better connect climate-related scientific research with in-the-field decision-making processes. The results of the study found that the average temperature over the study area is anticipated to increase by 1.7°C to 2.4°C in the twenty-first century based on the different emission scenarios with a rate of change that is more pronounced during the second half of the century. Summer and fall seasons are projected to have more significant temperature increases, while the northwestern portions of the region are projected to experience more significant increases than the Gulf coast region. Precipitation projections, conversely, do not exhibit a discernible upward or downward trend. Late twenty-first century exhibits slightly more precipitation than the early century, based on the A1B and B1 scenario, and fall and winter are projected to become wetter than the late twentieth century as a whole. Climate changes on the city level show that greater warming will happened in inland cities such as Oklahoma City and El Paso, and heavier precipitation in Nashville. These changes have profound implications for local water resources management as well as broader regional decision making. These results represent an initial phase of a broader study that is being undertaken to assist SCIPP regional and local water planning efforts in an effort to more closely link climate modeling to longer-term water resources management and to continue assessing climate change impacts on regional hazards management in the South.
West Africa is one of the fastest growing regions of the world and depends heavily on rain-fed ag... more West Africa is one of the fastest growing regions of the world and depends heavily on rain-fed agriculture for its food production. This study evaluates 12 freely available land-cover and land-use (LCLU) data sets at the ecoregion, country, and pixel levels in West Africa to estimate croplands. The selected data sets are primarily derived using remote-sensing data, representing different time periods and using various classification schemes. The result shows a very high variability of the estimated cropland at all levels. Despite this variability, data sets having a finer spatial resolution and representing a similar time period – specifically data from the International Institute for Applied Systems Analysis-International Food Policy Research Institute (IIASA−IFPRI), Global Land Cover−Share (GLC−Share), Moderate Resolution Imaging Spectroradiometer–University of Maryland (MODIS−UMD), Global Cropland Extent, Moderate Resolution Imaging Spectroradiometer−International Geosphere Biosphere Programme (MODIS−IGBP), and GlobCover version 2.3 (GlobCover V23) – estimated comparable cropland areas at the ecoregion and country levels. The countrywide cropland area, obtained from the selected data sets, when compared with the sum of arable land and permanent crop area obtained from the Food and Agriculture Organization (FAO), showed a high coefficient of determination (R2 > 0.95) for IIASA–IFPRI and GLC−Share. At the pixel level, at the original resolution, the newer data sets have a comparable user’s accuracy (UA>53%) and producer’s accuracy (PA>46%), except for the Global Cropland Extent data. Overall, two data sets – IIASA−IFPRI and GLC−Share – performed better in the region to estimate the cropland area at all levels.
A global digitized inventory of floods is needed for assessing the spatial distribution and tempo... more A global digitized inventory of floods is needed for assessing the spatial distribution and temporal trends of flood hazards and for evaluating flood prediction models. This study describes the development of a global flood catalog compiled from news reports, scholarly articles, remote sensing images, and other natural hazard databases. The events cataloged in the inventory include information on the geographic location, date, duration, affected population, information source, and a qualitative measure of the event's magnitude and location accuracy. To minimize biases we cross-checked the catalog with different sources and eliminated any redundancies. This research presents the compilation methodology used to develop a digitized Global Flood Inventory (GFI) for the period 1998-2008. This global flood inventory differs from other flood catalogs by providing a publicly available spreadsheet that details all events with both descriptive and digitized information. This inventory has been proven useful for mapping natural hazards over the globe and for evaluating flood prediction model. This global flood inventory research compliments our companion catalog: global landslide hazards.
ABSTRACT Changes in the patterns, means, and extremes of precipitation affect the spatiotemporal ... more ABSTRACT Changes in the patterns, means, and extremes of precipitation affect the spatiotemporal distribution and magnitude of floods. Availability of satellite precipitation products from TRMM-based Multi-satellite Precipitation Analysis (TMPA) since 1998 motivated this study to assess the distribution of floods on a global basis. First, a digitized Global Flood Inventory (GFI) for the period of 1998-2008 has been developed from multiple sources. The GFI was used to evaluate retrospective simulations from NASA’s Global Flood Modeling (GFM) system, driven by TMPA and other meteorological forcing data. The evaluation is based on four different strategies: a) rainfall threshold, b) excess rainfall generated from a hydrological model, c) routed excess rainfall, and d) grid-based return period analysis of routed excess rainfall from c. Analysis of the results shows that the strategy based on the return periods of routed excess rainfall in d has the highest probability of detection while maintaining relatively low false alarm rates. Finally, both the observed GFI and simulated GFM results were used to map spatial patterns and temporal trends of global floods over the past decade.
This study aims to examine how future climate, temperature and precipitation specifically, are ex... more This study aims to examine how future climate, temperature and precipitation specifically, are expected to change under the A2, A1B, and B1 emission scenarios over the six states that make up the Southern Climate Impacts Planning Program (SCIPP): Oklahoma, Texas, Arkansas, Louisiana, Tennessee, and Mississippi. SCIPP is a member of the National Oceanic and Atmospheric Administration-funded Regional Integrated Sciences and Assessments network, a program which aims to better connect climate-related scientific research with in-the-field decision-making processes. The results of the study found that the average temperature over the study area is anticipated to increase by 1.7°C to 2.4°C in the twenty-first century based on the different emission scenarios with a rate of change that is more pronounced during the second half of the century. Summer and fall seasons are projected to have more significant temperature increases, while the northwestern portions of the region are projected to experience more significant increases than the Gulf coast region. Precipitation projections, conversely, do not exhibit a discernible upward or downward trend. Late twenty-first century exhibits slightly more precipitation than the early century, based on the A1B and B1 scenario, and fall and winter are projected to become wetter than the late twentieth century as a whole. Climate changes on the city level show that greater warming will happened in inland cities such as Oklahoma City and El Paso, and heavier precipitation in Nashville. These changes have profound implications for local water resources management as well as broader regional decision making. These results represent an initial phase of a broader study that is being undertaken to assist SCIPP regional and local water planning efforts in an effort to more closely link climate modeling to longer-term water resources management and to continue assessing climate change impacts on regional hazards management in the South.
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Papers by Pradeep Adhikari