Sensitivity of Tropical Cyclone Induced Ocean Response to Wind Stress

Sue Chen1, James D Doyle2, Jayaram Veeramony3, William Rogers4, Yalin Fan5, Paul Martin6 and Timothy J Campbell4, (1)Naval Research Lab Monterey, Marine Meteorology, Monterey, CA, United States, (2)NRL, Monterey, CA, United States, (3)US Naval Research Laboratory, Stennis Space Center, MS, United States, (4)Naval Research Lab, Stennis Space Center, MS, United States, (5)US Naval Research Laboratory, Stennis Space Center, LA, United States, (6)University of Guelph, Engineering, Waterloo, ON, Canada
Abstract:
Significant efforts have been made in recent years to improve the track and intensity forecasts of Navy’s operational Coupled Ocean/Atmosphere Mesoscale Prediction System for Tropical Cyclone (COAMPS-TC). In this study, we illustrate some key challenges related to TC intensity prediction and air-sea interaction processes using COAMPS-TC coupled with the 3D circulation Navy Coastal Ocean Model (NCOM). We have identified a low intensity bias in COAMPS-TC partially stems from model biases in the momentum flux utilized by NCOM. We will discuss recent advancements in COAMPS to better quantify the prediction of momentum flux across the air-sea interface by coupling with a wave model Simulating Wave NearShore (SWAN). The recent case of hurricane Blanca (2015), a storm that occurred off the Baha California which produced a significant ocean cold wake of 4-6 °C, is used to examine the sensitivity of ocean response to wind stress in the air-ocean and air-ocean-wave coupled COAMPS-TC. The results show both the coupled TC track and intensity are differ substantially relative to the uncoupled COAMPS-TC. When the wind stress magnitude is reduced to just 1/3 of the uncoupled value, there is a significant damping of the ocean internal wave structure and cold wake magnitude.
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