Sea Surface Temperature Estimation From The Dmsp Operational Linescan System Using A Ssm I Derived Water Vapor Correction PDF Download

This is an interim report on an ongoing program to develop a passive microwave system for the remote all-weather measurement of sea surface temperature from a satellite platform. It presents the results of a theoretical investigation of the interdependence of the relevant environmental and instrumental parameters and their effect on the measured microwave brightness temperature and the sea surface temperature derived from it. The parameters considered are sea surface temperature, sea salinity, ocean roughness (wind speed), atmospheric water vapor, clouds, and the observational frequency. Detailed descriptions of the calculations of the emission and reflection of the sea surface, the emission and absorption of the atmosphere, the translation and rotation of the antenna properties from the satellite-oriented coordinate system to an earth-oriented system, and the convolution of the antenna reception pattern with the total radiatio over the earth's surface are given. Calculations of the microwave brightness temperature and of the uncertainty of the sea surface temperature derived from it for a range of values and uncertainties of the environmental conditions are presented. These calculations indicate that the optimum observational frequency for the determination of sea surface temperature lies between about 3 and 6 GHz. The dominant source of error is due to uncertainty in the effects of ocean roughness. A multifrequency microwave system will be required to correct for the effects of the various environmental factors and to obtain the sea surface temperature to an uncertainty of less than 1 deg C.