Effect of sea spray on the numerical simulation of super typhoon ‘Ewiniar’

Abstract

To study the potential effect of sea spray on the evolution of typhoons, two kinds of sea spray flux parameterization schemes developed by Andreas (2005) and Andreas and Wang (2006) and Fairall et al. (1994) respectively are incorporated into the regional atmospheric Mesoscale Model version 3.6 (MM5V3) of Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) and the coupled atmosphere-sea spray modeling system is applied to simulate a Western Pacific super typhoon Ewiniar in 2006. The simulation results demonstrate that sea spray can lead to a significant increase in heat fluxes at the air-sea interface and the simulated typhoon’s intensity. Compared with the results without sea spray, the minimum sea level pressure reduces about 8hPa after taking account of sea spray by Fairall et al.’s parameterization (1994) and about 5hPa by Andreas’ (2005) and Andreas and Wang’s (2006) parameterization at the end of the model integration, while the maximum 10m wind speed increases about 17% and 15% on average, respectively, through the entire simulation time period. Taking sea spray into account also causes significant changes in Tropical Cyclone (TC) structure due to an enhancement of water vapor and heat transferred from the sea surface to the air; therefore, the center structure of the typhoon becomes more clearly defined and the wind speed around the typhoon eye is stronger in numerical experiments. The simulations show that different sea spray flux parameterizations make different modifications to the TC structure.