Investigating the Coupled Model Impact and Air-Sea Interaction Mechanism Using Observation from TAHOPE (2022) Field Campaign

Severe weather systems such as tropical cyclones, mei-yu fronts, and afternoon thunderstorms have a great social impact in Taiwan. It has long been recognized that air-sea interaction plays a crucial role in the development of tropical cyclones. However, for other severe weather systems, although some studies suggest that the air-sea interaction could modulate the low-level moisture transport in mei-yu front events, its impact has received less attention. To enhance our understanding of air-sea coupled processes in these high-impact weather systems and explore the potential of air-sea coupled models, we conduct numerical experiments using the high-resolution atmosphere-wave-ocean fully coupled model, Unified Wave INterface-Coupled Model (UWIN-CM) and verify with the observations collected during the Taiwan-Area Heavy rain Observation and Prediction Experiment (TAHOPE) field campaign in 2022.

In this study, 3-day forecasts from UWIN-CM are initialized twice daily during the TAHOPE field campaign. At each initialization time, three types of forecasts are conducted: uncoupled atmosphere (UA), atmosphere-ocean coupled (AO), and atmosphere-wave-ocean fully coupled (AWO) simulations. Observations collected during the campaign include data from multiple radars, radiosondes, and satellites. By comparing these model simulations with TAHOPE observations, we evaluate the impact of using a high-resolution fully coupled model on predicting severe weather events in Taiwan. Additionally, we investigate the role of air-sea interaction and the dynamical processes in these events.