TOGA COARE: The Coupled Ocean—Atmosphere Response Experiment

Abstract

Despite significant progress in the Tropical Ocean?Global Atmosphere (TOGA) program, a number of major hurdles remain before the primary objective, prediction of the variability of the coupled ocean?atmosphere system on time scales of months to years, can be achieved. Foremost among these hurdles is understanding the physics that maintains and perturbs the western Pacific warm pool, the region of the warmest sea surface temperature in the open oceans, which coexists with the largest annual precipitation and latent heat release in the atmosphere. Even though it is believed that the warm pool is a ?center of action? for the El Niño?Southem Oscillation (ENSO) phenomena in the ocean and the atmosphere, successful simulation of the warm pool has remained an elusive goal. To gain a clear understanding of global climate change, the ENSO phenomenon, and the intraseasonal variability of the coupled atmosphere?ocean system, it is clear that a better specification of the coupling of the ocean and the atmosphere is required. An observational and modeling program, the TOGA Coupled Ocean?Atmosphere Response Experiment (TOGA COARE), has been designed to work toward this goal. The scientific goals of COARE are to describe and understand: 1) the principal processes responsible for the coupling of the ocean and the atmosphere in the western Pacific warm-pool system; 2) the principal atmospheric processes that organize convection in the warm-pool region; 3) the oceanic response to combined buoyancy and wind-stress forcing in the western Pacific warm-pool region; and 4) the multiple-scale interactions that extend the oceanic and atmospheric influence of the western Pacific warm-pool system to other regions and vice versa. To carry out the goals of TOGA COARE, three components of a major field experiment have been defined: interface, atmospheric, and oceanographic. An intensive observation period (IOP), embedded in a period of enhanced meteorological and oceanographic monitoring, will occur from November 1992 through February 1993 in the western Pacific region bordered by 10°N, 10°S, 140°E, and the date line. The experimental design calls for a complex set of oceanographic and meteorological observations from a variety of platforms that will carry out remote and in situ measurements. The focus of the observational effort will be in an intensive flux array (IFA) centered at 2°S and 156°E. The resulting high-quality dataset is required for the calculation of the interfacial fluxes of heat, momentum, and moisture, and to provide ground truth for a wide range of remotely sensed variables for the calibration of satellite-derived algorithms. The ultimate objective of the COARE dataset is to improve air-sea interaction and boundary-layer parameterizations in models of the ocean and the atmosphere, and to validate coupled models.