Abstract
Global warming is projected to have a considerable impact on the hydrological cycle, which is expected to further influence the redistribution of water resources. Hydroclimatic extremes, e.g., floods and droughts, vary spatially and temporally, considerably affecting local economies and communities globally.
In this dissertation, the first study investigates the performance of six commonly used satellite-based precipitation products (SPPs), e.g., NASA GPM IMERGF, using the proposed Comprehensive Assessment Framework of Rainfall (CAFR) and the hydrological model Soil and Water Assessment Tool (SWAT) over eleven river basins covering seven distinct climate regions in Vietnam. The second study builds upon the findings of the first by utilizing the most recent General Circulation Models (GCMs) from the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6) for disaster mapping by 2100 over the coastal, risk-prone region—namely, the Eastern Shore of Virginia.
Lastly, motivated by the second chapter’s finding that drought trends are projected to increase through 2044, the third chapter examines the historical development of drought conditions as far back as 1950, especially before and after 1982—the year highlighted by the National Oceanic and Atmospheric Administration (NOAA) as having a warming rate of 0.36°F (0.20°C) per decade, more than three times the long-term average (0.11°F or 0.06°C / decade) since 1850. Specifically, drought-related characteristics, especially recovery, remain critically underexplored, particularly on a global scale. Herein, my work presents an up-to-date, unique, and comprehensive assessment of global drought conditions and recovery using soil-moisture-based drought indices, chosen for their strong relevance to agricultural drought and soil moisture deficits, as well as their ability to capture critical seasonal dynamics. A total of five soil moisture datasets have been used, including NASA Soil Moisture Active and Passive (SMAP) (2015–2024), ECMWF Reanalysis v5 (ERA5)-Land (1950–2024), European Space Agency (ESA) Climate Change Initiative (CCI) Active and Combined (1978–2023), and Global Land Evaporation Amsterdam Model (GLEAM) (1980–2024), representing both model reanalysis and satellite products. Overall, this dissertation showcases efforts to reveal the recent impacts of natural disasters while maximizing the use of satellite remote-sensing datasets, which are important for stakeholders, authorities, and communities in disaster prevention, prediction, and water resources management.
