台灣地區西南氣流引發豪雨之研究(II-III)

This study investigated the heavy rain event occurring in central and southern Taiwan from 11 to 13 June 2016, using the Weather Research and Forecasting (WRF) model and the Ensemble Adjustment Kalman Filter (EAKF) data assimilation system. The GPS radio occultation (RO) data were assimilated and their impact on the rainfall was evaluated by examining the changes of the wind and moisture structures of southwesterly flows after the data assimilation procedure. It is found that the GPS RO data assimilation can help the 0-36 h rainfall simulation, but not after 36 h. Those ensemble members that produced better rainfall simulation exhibit less moisture transport than the other members, such that the rainfall amount is reduced and becomes more consistent with the observation. The GPS RO data assimilation can reduce the low-level moisture and modify the vertical structure of southwesterly flows, resulting in a better rainfall simulation.