EVALUATION OF SEA-SURFACE TEMPERATURE-MEASUREMENTS FROM DRIFTING BUOYS

Three drift-buoy designs have been deployed since 1988 in substantial numbers in the tropical Pacific Ocean by United States participants as part of the Tropical Ocean Global Atmosphere (TOGA) Pan Pacific Surfa ce Current Study. These include the Low Cost Tropical Drifter designed and built at the Atlantic Oceanographic and Meteorological Laboratory , the Low Cost Drifter (LCD) designed and built by the Massachusetts I nstitute of Technology Draper Laboratories, and the Ministar Drifter d esigned and built at the Scripps Institution of Oceanography and built by Tecnocean Inc., San Diego, California, which has subsequently beco me known as the World Ocean Climate Experiment standard drifter. This report contains an evaluation of the performance of the sea surface te mperature measurement system carried by these buoy designs. Based on c omparisons of the monthly mean SST derived from the available XBT and CTD casts and on intercomparisons among each of the buoy types, all th ree designs appear to include a warm bias in the surface temperatures they report. The LCD showed a larger mean bias and diurnal variation f rom solar heating than the other two buoy types. This difference is pr obably due to the location chosen for its sensor, resulting in poor th ermal contact with the surrounding water.