Investigating the mechanisms of an intense coastal rainfall event during TAHOPE/PRECIP-IOP3 using a multiscale radar ensemble data assimilation system

The field campaign aimed to understand the dynamics, thermodynamics, and predictability of heavy rainfall events in the Taiwan area. This study investigated the mechanisms of a heavy rainfall event that occurred on 6–7 June during the intensive observation period 3 (IOP3) of the field campaign.

Heavy rainfall occurs on Taiwan’s western coast when a mei-yu front hovers in northern Taiwan. A multiscale radar ensemble data assimilation system based on the successive covariance localization (SCL) method is used to derive a high-resolution analysis for forecasts. Two numerical experiments are conducted with the use of convective-scale (Experiment RDA) or multiscale (Experiment MRDA) corrections in the assimilation of the radial velocity from operational radars at Chigu and WuFen and the additional S-band dual-polarization Doppler radar (S-Pol) deployed at Hsinchu during the field campaign.