The Sources of Error in Rain Amount Estimating Schemes from GOES Visible and IR Satellite Data

Abstract

Recent work in GOES satellite rain amount estimation techniques suggests that these satellites primarily show skill in estimating areas of rain, rather than rain amounts directly. This hypothesis is quantitatively investigated by examining the errors in estimating rain areas from the satellite data separately from the errors involved in estimating the rain amount from known rain areas. These errors, when combined, are shown to be of the same magnitude as the errors obtained by direct rain amount estimation, giving firm support for techniques using independent rain area and amount estimation schemes. For Montreal, the rms error in hourly estimates produced by the rain area estimation technique was found to be 22% as compared to the 44% for estimating the rain amount from known rain areas. For independent processes, this yields an rms error of 49% for satellite rain amount estimation.