Deciphering changes in rainfall events and the consequences over Texas under global warming

Tabassum, Sabiha
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The far-reaching impacts of global warming on precipitation patterns warrant our unwavering attention. As the atmosphere heats up, heightened water vapor levels lead to more intense and frequent severe weather, exacerbating the risk of floods. Conversely, shifts in rainfall distribution could incite prolonged droughts and diminished water access in specific regions. Given the societal and economic repercussions of these extremes, comprehending their evolving nature becomes paramount. This study employs General Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to explore shifts in rainfall and their consequences for Texas amid global warming. In Chapter 2, I meticulously evaluate the performance of the CMIP6 GCMs in representing the observed rainfall characteristics over Texas. Subsequently, I scrutinize projections from the most accurate GCMs to estimate changes in extreme rainfall events. The analysis reveals a more pronounced increase in the annual maximum 5-day rainfall (Rx5day) in the near-future (2021-2050) than long-term (2071-2100) when compared to the historical period (1985-2014). In Chapter 3, I use a data driven approach to develop a statistical relationship between flood height at critical infrastructures and precipitation during historical tropical cyclones (TC) in Texas. This relationship is then extrapolated to anticipate future flood risks based on projected extreme rainfall. The findings illuminate heightened vulnerabilities to damage and disruptions from future TC-induced floods in specific areas. In Chapter 4, I assess prospective changes in streamflow within the Colorado River Basin (CRB) using GCMs selected based on their ability to represent the observed climatic characteristics over the CRB. The results signal substantial alternations in CRB streamflow and an escalated probability of extreme flow occurrences. Cumulatively, this dissertation underscores the urgency for adaptable strategies to confront the intricate challenges stemming from evolving Texas rainfall patterns in a warming climate.