The influences of ocean on intensity of Typhoon Soudelor (2015) as revealed by coupled modeling

Abstract

Typhoon Soudelor (2015) moved northwestward toward Taiwan and passed several mesoscale ocean eddies over the open ocean. A high‐resolution air–sea coupled model HWRF is employed to simulate Soudelor. Coupled model with low‐ or high‐resolution ocean conditions can largely reduce the over‐intensification of the typhoon from uncoupled modeling. Coupled modeling with a more realistic finer‐resolution Hybrid Coordinate Ocean Model (HYCOM) analysis helps better capture the rapid weakening of the super‐intense typhoon for the first 2 days and the following re‐intensification before 80 hr, due to the initial more realistic ocean conditions. The rapid weakening is related to the existence of initial cold core ocean eddies near the earlier typhoon, while the warm core eddies tend to decrease the typhoon‐induced SST cooling and thus induce the re‐intensification of the later typhoon. The typhoon boundary layer is shallower at the rear‐right quadrant of the moving typhoon than that at other quadrants. The coupled modeling results show that a much shallower boundary layer lower than 200 m is produced at the rear‐right quadrant for the super‐intense typhoon as the typhoon passes over cold core eddies and induces stronger SST cooling. In addition, stronger typhoon cold wake in coupled experiments induces larger inflow angles at lower levels at the rear‐right quadrant than other studies. The simulated track near and after landfall at east Taiwan is also improved for the coupled experiment compared to the uncoupled experiment.