Effect of High-Resolution Topography in Simulations of Hurricane Maria's Landfall in Puerto Rico

The atmospheric processes involved in a tropical cyclone are affected by topographical factors during and after landfall. Interactions with land are capable of changing the tropical cyclone’s structure and behavior, and, ultimately, its impact on the landmass. However, one of today’s forecasting challenges is that numerical weather prediction models cannot resolve many of the factors that influence surface weather, resulting in a forecast that predicts the expected behavior of a tropical cyclone moving over a smooth landmass. Therefore, these models do not accurately represent the impact at landfall of these systems in regions that are characterized by a complex terrain and multiple mountain ranges. This research project investigated how terrain resolution affects the landfall and behavior of tropical cyclones focusing on the landfall of Hurricane Maria in Puerto Rico in 2017. A set of simulations were incorporated and produced by the Weather Research and Forecasting (WRF) model, where one of the simulations used the default terrain resolution and the other used high-resolution terrain data. It was shown that the magnitude of the wind speed, vertical velocity, and precipitation was higher in the mountainous interior of the island when incorporating high-resolution terrain. In addition, ensemble forecasts demonstrated that high-resolution terrain data in hurricane simulations produced more realistic results in terms of the hurricane structure and behavior. It was concluded that high-resolution land data leads to more accurate forecasts in cases when tropical cyclones interact with a landmass.