Abstract
A fully-coupled atmospheric-ocean model was developed by coupling WRF (Weather Research and Forecasting Model) with FVCOM (the unstructured-grid, Finite-Volume Community Ocean Model) through the Earth System Model Framework (ESMF). The combined FVCOM and WRF is designed for multi-domain configurations for both atmospheric and ocean model components. The data exchange between structured-grid WRF and unstructured-grid FVCOM is achieved through ESMF. The coupled WRF-FVCOM system includes wave-current interactions with either hydrostatic or non-hydrostatic dynamics for the ocean. This coupled system has been released to the public in FVCOM v5.0.The coupled FVCOM-WRF system was applied to simulate the 2012 Hurricane Sandy in the Atlantic Ocean, with an aim to examine 1) the impact of air-sea interactions on hurricane’s intensity and path and 2) oceanic responses to Sandy under hydrostatic and nonhydrostatic conditions. The experiments were performed for four cases with WRF, WRF-OML (ocean mixed layer model), and hydrostatic and non-hydrostatic coupled WRF-FVCOMs. The model-data comparison results show that the storm’s modeled intensity and pathway can be substantially improved when including the ocean feedback in the WRF simulation. Both hydrostatic and nonhydrostatic coupled WRF-FVCOM model results show that oceanic responses to Sandy were stronger on the right side of the hurricane center, with greater asymmetry non-hydrostatic runs. The near-inertial resonance responses occurred when the clockwise-rotating frequency of storm winds was close to the local inertial frequency in an area 100-200 km away from the hurricane center. The simulated ocean responses agreed with the theoretical work of Price (1981),The non-hydrostatic coupled WRF-FVCOM experiment used a 2-km resolution grid, which cannot fully resolve the non-hydrostatic convection process over the continental shelf. Further investigation is required to verify the influence of storm-induced convection on tropical storms over the shelf using a model which can resolve the convection.