COLA Report 20
Intercomparison of Atmospheric Model Wind Stress with Three
Different Convective Parameterizations: Sensitivity of Tropical Pacific
Ocean Simulations
Ben P. Kirtman and David G. DeWitt
September 1995
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 used 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 circulation and temperature
fields are compared with the National Meteorological Center 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 circulation and
temperature fields that are 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, we conclude 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 - 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 are too narrowly confined to the western Pacific
which leads to sea surface temperature anomalies that are concentrated in the western Pacific
with little or no sea surface temperature anomaly in the east. The sub-surface temperature
anomalies along the equator are best simulated with the wind stress from the relaxed Arakawa-Schubert parameterization.
Complete copies of this report are available from:
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last update: 26 September 1995
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