Ocean Surface Wave Effects on Explosive Cyclone with Atmosphere-Ocean-Wave Coupled Model

An explosive cyclone develops rapidly with ocean surface wave growing. Air-sea interactions controlling surface heat flux and stress are heavily dependent on ocean wave physical process. To investigate the influence of surface wave on atmospheric and oceanic turbulence in their boundary layers under an explosive cyclone condition, sensitivity experiments with the atmosphere-ocean-wave coupled model are implemented on the explosive cyclone emerged in January 2018 above the Northwestern Atlantic.

For the coupled model, the WRF (Weather Research and Forecasting Model), the CROCO (Coastal and Regional Ocean COmmunity model), and the WAVEWATCH III model are utilized for its components. In order to examine effects derived from surface waves, two model cases are experimented: the AO (WRF-CROCO coupled model) case and the AWO (WRF-WAVEWATCH II-CROCO) case. At the highest deepening phase, the explosive cyclone in the AO case develops up to 949.7hPa in its minimal sea level pressure, while the counterpart in the AWO case is higher by 2.1hPa. When the wave model is coupled the surface roughness and surface stress amplified by a few percents, hence the surface wind speed slightly decreased. Due to the increase of the surface stress, the intensity of the inertial oscillation of ocean current invoked by the cyclone is enhanced up to 20%. It generates stronger vertical velocity shear in the mixed layer, resulting in deeper mixed layer depth and cooler sea surface temperature. Though the process of ocean surface wave shows slight significance to change the development of the explosive cyclone, it takes much influence on turbulence in the atmospheric and oceanic boundary layer.