High-Resolution Reanalysis for Hurricanes Surface Forcing

A systematic technique of reanalysis has been developed to post-process hurricane model forecasts to improve the accuracy of high-resolution surface forcing fields to support the Hurricane surge and ocean community. The method is demonstrated to utilize the forecasts of Hurricanes Florence (2018), Matthew (2016) and Irene (2011) using the Navy’s Coupled Ocean-Atmosphere Mesoscale Prediction System for tropical cyclone (COAMPS-TC), to create high-resolution surface reanalysis with the improved storm intensities and locations, including the timing, location and storm structure during the landfalls. The surface reanalysis fields are created by merging the triple-nested short-range (1-6 h) regional forecasts. The best track is used to calibrate and improve not only the storm intensities and structures, but also the correlated surface wind stresses and surface heat fluxes. Results demonstrate that the reanalysis of the maximum surface wind speed and minimum sea-level pressure match the best track very well. Surface winds from the reanalysis are verified with buoy observations in both wind speed and direction, suggesting that the wind distribution and timing of the storm passage agree well with the observations. This methodology is capable of significantly improving the surface meteorological forcing, which assists the hurricane surge and ocean wave communities to better assess hurricane impacts on the coastal environment.