Derivation of ocean—Atmosphere heat fluxes in a tropical environment using satellite and surface data

Abstract

AbstractOcean—atmosphere heat fluxes measured at John Brewer Reef (80 km north‐north‐east of Townsville, Australia) were compared with regional heat fluxes estimated from non‐direct surface data and information from a number of satellite sensors. Data from the visible channel of the Japanese Geostationary Meteorological Satellite (CMS) were collected for the location, as well as daily atmospheric soundings from NOAA‐9. Sea‐surface temperatures were obtained from a blend of ship observations and NOAA‐9 data. A relationship was developed that estimated solar radiation from GMS visible reflectance data. Incoming longwave radiation was estimated with the LOWTRAN 6 radiative transfer model applied to profiles of temperature and humidity derived from NOAA‐9 soundings. The bulk aerodynamic formulation was used to form regional estimates of the turbulent heat fluxes, combining wind speed from the Darwin Tropical Wind Analysis, blended sea‐surface temperatures, and near‐surface specific humidity related to satellite‐derived precipitable water vapour. A variety of approaches for estimating the near‐surface specific humidity were examined. The root mean square differences (measured—estimated) between the weekly averaged values of the net solar radiation flux, the net longwave radiation flux, the total turbulent heat flux, and the total ocean—atmosphere heat flux were estimated as 12, 10, 45 and 50 Wm−2 respectively. Time series of the weekly heat fluxes are presented for the period June 1985 to April 1986.