Comparison of Atmospheric Model Wind Stress with Three Different Convective Parameterizations: Sensitivity of Tropical Pacific Ocean Simulations

Abstract

The Geophysical Fluid Dynamics Laboratory ocean model has been used to diagnose the sensitivity of the Center for Ocean?Land?Atmosphere Studies atmospheric general circulation model wind stress to convective parameterization. In a previous study this atmospheric model was integrated for seven years with observed sea surface temperatures to test three different convective parameterizations: Kuo, Betts?Miller, and relaxed Arakawa?Schubert. In this study, the three wind stress fields are then used to force the ocean model. For comparison, an ocean model simulation with the subjectively analyzed Florida State University wind stress product is also made. The resulting ocean temperature field is compared with the National Centers for Environmental Prediction ocean analyses in terms of the annual cycle and interannual variability in order to identify errors in the ocean model and errors that are unique to the particular wind stress field. Overall, the ocean simulation with the wind stress resulting from the relaxed Arakawa?Schubert parameterization gives a thermal structure that is in best agreement with the analyzed wind stress simulation and the ocean analyses. Based on the simulation of the annual cycle of sea surface temperature and heat content in the deep Tropics, it is concluded that the wind stress is too strong with the Betts?Miller parameterization and too weak with the Kuo parameterization, particularly in the boreal spring. The simulation with the wind stress from the relaxed Arakawa?Schubert parameterization minimizes the errors in the heat content between 10°S and 10°N and has smaller errors than the analyzed wind stress simulation in some regions. In terms of interannual variability, the anomalies from all three wind stress products produce sea surface temperature anomalies that are concentrated in the western Pacific with little or no sea surface temperature anomaly in the east indicating that the ocean model has some difficulty capturing the remote response to anomalous wind stress forcing. However, the subsurface temperature anomalies along the equator are best simulated with the wind stress from the relaxed Arakawa?Schubert parameterization.