Wetlands to Skyline: Investigating the Hurricane Rainfall Patterns due to Urban Expansion

Hurricanes are one of the most destructive natural phenomena affecting human populations, infrastructure, and economies. The frequency of hurricane landfalls in coastal regions, particularly in the southeastern and southwestern parts, has been a growing concern due to their profound impacts on rapidly expanding urban areas. The evolving landscape, characterized by alterations in land use and land cover change (LULCC), notably the progression of urbanization and variations in antecedent soil moisture conditions, has been identified as a crucial factor influencing hurricane dynamics. Urbanization, in particular, is capable of perturbing precipitation patterns, surface substructures, and even near-surface wind profiles. This study used a combination of observational analyses, mesoscale modeling through the Weather Research and Forecasting (WRF) model, and idealized simulations employing the Cloud Model (CM1) to understand the dynamics of hurricane rainbands and changes associated with the underlying land surface characteristics. Specifically, this research focuses on three significant hurricane events – Harvey 2017, Rita 2005, and Ike 2008 – that made landfall around the Houston city, enabling a comprehensive exploration of their rainband characteristics. The experiments are being done by replacing the model surface properties like LULC and greenfrac from 2001 and 2017 so that the model can simulate the realistic land surface characteristics to simulate hurricane rainbands. Modeling analysis shows the enhancement of rainbands which eventually leads to increase in precipitation over the urban area and the similar characteristics found in all the three hurricanes, and similar rainband characteristics are also supported by the sensitivity experiments done by altering the water vapor mixing ratio. Furthermore, this study incorporates idealized experiments facilitated by the CM1 model, wherein variations in surface roughness are manipulated. Several idealized experiments using the CM1 model by changing the surface roughness have also been performed to support the conclusion from the WRF model, and found the same dynamics behind the enhancement of rainbands. This study presents a comprehensive analytical framework which uses the observational insights and numerical modeling, which collectively deepen our understanding of the dynamics of hurricane rainbands. As cities keep growing near the coasts, this research is really important for getting ready for disasters, planning cities, and coming up with ways to lessen the problems caused by heavy rain during hurricane landfall.