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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 rearright 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. K E Y W O R D Scold core eddy, typhoon-ocean interaction, Typhoon Soudelor (2015)

Typhoon Megi (2016) headed northwestward toward Taiwan with southward deflection near landfall. In this study, Hurricane Weather Research and Forecast system (HWRF) was used to investigate the mechanism of the track changes over free ocean and track deflection near landfall. HWRF simulations using more realistic Hybrid Coordinate Ocean Model sea surface temperature (SST) analysis improve the northward biased track compared with that using Global Forecast System SST, due to the initial cooler SST below the storm path. The initial warmer Global Forecast System SST leads to a northward track shifting with an overintensified typhoon. As the Princeton Ocean Model is coupled, the SST over South China Sea becomes warmer leading to a northward track shifting compared to a southward shifting induced by the upper ocean cooling due to the typhoon-ocean interactions in the vicinity of the typhoon. Regardless of track shifting, southward deflection near landfall is mainly controlled by orographic effects of the Central Mountain Range (CMR). Cyclonic northerly is enhanced to the west of the typhoon center ahead and over the CMR that results in southward deflection. Diagnostics of potential vorticity (PV) tendency budget indicates that southward deflection can be explained by the southeastward tendency of latent heating effects near landfall. The combined effects of latent heating and cyclonic rotation of positive wave numer-1 (WN-1) potential vorticity vertical advection dominate the southward deflection when the typhoon is closer to Taiwan. Furthermore, the typhoon movement near landfall is slowed down mainly due to WN-1 negative vertical differential latent heating over the northern CMR.

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