Comparison of Wind Stresses Derived from Archived Operational European Centre for Medium-Range Weather Forecasts 1OOO-mb Winds and Florida State University Pseudo Stresses over the Tropical Pacific Ocean, 1981-1993

摘要

Monthly wind stresses are computed from the European Centre for Medium-Range Weather Forecasts (ECMWF) operational 12 hrly global wind analyses. These are compared with wind stresses derived from the Florida State University (FSU) monthly pseudo stresses (observational data) over the tropical Pacific Ocean domain from 1981-1993. The FSU product is used as the standard for comparison because it was derived using the same procedures and data type. During 1982-1985, ECMWF equatorial trade winds are 25-55% weaker than those from FSU and the wind stress curl is more diffuse in the northern tropical gyre. Stronger topographically-induced wind features occur in the ECMWF product around the Hawaiian Islands and Central American coast. During 1990-1993, equatorial trade wind magnitudes agree to within 20%, primarily due to uncorroborated strengthening of the ECMWF trade winds (a result of ECMWF product modifications) . The ECMWF wind stress curl in the northern tropical gyre is more concentrated. The topographically-induced wind features in the ECMWF product around the Hawaiian Islands and along the Central American coast are smaller in size and stronger. The strengthening in these regions is not corroborated by the FSU product.