Coupled Ocean-Atmosphere Response Experiment (COARE): An interim report

This paper is an interim report on results of the Coupled Ocean-Atmosphere Response Experiment (COARE), conducted from November, 1992, through February, 1993, in the equatorial western Pacific. Early work has emphasized data from single platforms or sensors; more profound, cross-cutting research, using multiple data sets to address ocean-atmosphere interaction, is only now yielding results. Three episodes of the intraseasonal oscillation (ISO) occurred during COARE. Atmospheric effects extended well outside the tropics. Each ISO episode was accompanied by numerous deep convective events, loosely organized on lengthscales from 10 - 10,000 km and timescales from hours to weeks. Similar lengthscales and timescales were evident in all atmospheric variables and in sea surface temperature (SST). We report detailed observations of precipitation and winds from shipborne and airborne radars; atmospheric heat and moisture budgets from sounding arrays; boundary layer properties and fluxes from ships, buoys, and aircraft; ocean heat and freshwater budgets; and numerous ancillary observations. Emphasis has been on achieving accurate heat, momentum, and freshwater fluxes, on documenting the diurnal cycle, on understanding the role of freshwater fluxes in controlling SST, and on obtaining the morphology of typical convective events. Large-scale context is provided by satellite observations and numerical weather prediction (nwp) output. However, comparison of in-situ data with nwp products shows systematic discrepancies with winds, scales of convective events, and surface fluxes. Some new parameterizations and early modeling results are reported. Further improvements in modeling the coupled ocean-atmosphere system are anticipated, based on COARE results.