"Because data derived from satellite radiance measurements are being used increasingly in the analysis/forecast cycle, it is important that the accuracy of satellite-derived data be determined. Such determinations have been made by Johnson (1973, 1974) who compared satellite VTPR temperature soundings with rawinsonde profiles located within 1° latitude of each other and no more than 3 hours apart in time. These comparisons show root-mean-square differences between satellite and rawinsonde temperatures of 1.5°C to 4°C, depending upon elevation and latitude, with an average value of about 2.0°C at 500 mb. Similar comparisons between "co-located" satellite and rawinsonde soundings have been made by Jastrow and Halem (1973). The non-simultaneity in space and time of these paired observations has led to the criticism that the differences so determined are greater than the true differences that would be found between simultaneous and co-located satellite and rawinsonde observations"--Introduction.

National Weather Service (NWS)

United States