COARE

COARE The Coupled Ocean–Atmosphere Response Experiment (COARE) was a major multinational field program in the western tropical Pacific designed to investigate air–sea interaction processes influencing tropical convection, circulation, and variability. It brought together research centers, universities, and agencies to coordinate ship, aircraft, buoy, and island-based observations that fed modeling efforts and operational forecasting activities. The program's integrated approach linked process studies, observational networks, and numerical models to improve understanding of coupled phenomena relevant to regional and global climate.

Overview

COARE was organized as a collaborative campaign involving prominent institutions such as the National Center for Atmospheric Research, Woods Hole Oceanographic Institution, Scripps Institution of Oceanography, University of Hawaii, and national meteorological services including the Australian Bureau of Meteorology, the Japan Meteorological Agency, and the National Oceanic and Atmospheric Administration. Field operations centered in the western equatorial Pacific near the Equator and the Mariana Islands, with logistics using research vessels, aircraft from NASA, and instrumented island sites like Pohnpei and Palau. The experiment aligned with larger programs including TOGA and influenced subsequent initiatives such as TAO and Arctic Climate Impact Assessment-related studies on coupled processes.

Objectives and Scope

COARE aimed to quantify fluxes of momentum, heat, and moisture across the air–sea interface, and to understand processes controlling tropical convective systems, the Intertropical Convergence Zone, and intraseasonal oscillations such as the Madden–Julian oscillation. Specific goals included improving parameterizations used in models developed at centers like the Geophysical Fluid Dynamics Laboratory and European Centre for Medium-Range Weather Forecasts, assessing observational strategies employed by networks including the Tropical Ocean Global Atmosphere program, and supporting operational forecast centers such as the Joint Typhoon Warning Center and Australian Bureau of Meteorology. The scope encompassed coupled boundary-layer dynamics, surface flux variability, ocean mixed-layer processes investigated by groups such as the Scripps Institution of Oceanography and Woods Hole Oceanographic Institution, and remote-sensing synergies with platforms operated by NASA and Japan Aerospace Exploration Agency.

Methodology and Instrumentation

COARE deployed a multi-platform observing system combining research ships like RV Knorr and RV Tangaroa, instrumented aircraft from NASA and CSIRO, moored arrays inspired by the TAO/TRITON array, drifting buoys akin to the Global Drifter Program, and island-based meteorological stations on sites comparable to Pohnpei and Palau. Instruments included sonic anemometers, infrared radiometers, bulk flux packages, and shipboard acoustic Doppler current profilers similar to systems used at Scripps Institution of Oceanography and Woods Hole Oceanographic Institution. The experiment integrated in situ microstructure profilers, upper-ocean thermistor chains influenced by techniques from Lamont–Doherty Earth Observatory, and airborne radar and dropsonde deployments modeled after methods from NOAA Aircraft Operations Center and NASA's ER-2. Data assimilation and modeling efforts utilized frameworks from the Geophysical Fluid Dynamics Laboratory, European Centre for Medium-Range Weather Forecasts, and research groups at University of Colorado Boulder and Massachusetts Institute of Technology.

Key Findings and Results

COARE produced seminal results on convective fluxes, demonstrating systematic relationships among surface wind stress, evaporation rates, and the organization of mesoscale convective systems—results that informed parameterizations used in models at GFDL, ECMWF, and operational suites at NOAA and the Australian Bureau of Meteorology. Observations clarified the role of diurnal heating over the Marshall Islands region and modified understanding of mixed-layer response to surface forcing as studied by teams from Scripps Institution of Oceanography and Woods Hole Oceanographic Institution. COARE datasets validated remote-sensing retrievals from TOPEX/Poseidon and TRMM and supported studies linking intraseasonal variability to the Madden–Julian oscillation and interannual phenomena including El Niño–Southern Oscillation. The campaign's quality-controlled archives enabled advances in coupled model development at institutions such as NOAA's Geophysical Fluid Dynamics Laboratory, MIT, and University of Washington.

Impact and Legacy

COARE's legacy includes enduring observational datasets archived and used by projects like the Tropical Ocean Global Atmosphere program and the Global Ocean Observing System, improved bulk flux algorithms adopted by NOAA and ECMWF, and enhanced design principles for moored arrays such as TAO/TRITON and the Proudman Oceanographic Laboratory's deployments. The program influenced subsequent field campaigns including TOGA COARE follow-ons, initiatives by NASA and JAXA on tropical convection, and modeling intercomparisons under the auspices of WCRP and CLIVAR. Training and collaboration during COARE strengthened ties among Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, University of Hawaiʻi at Mānoa, and international agencies, shaping research directions in tropical meteorology and oceanography for decades.

Category:Oceanography expeditionsCategory:Atmospheric sciences