Possibilities and Limitations for QPF using Linear-and Nonlinear-Based Nowcasting with Time-Sequenced Geosynchronous Satellite Imagery

A set of QPF nowcasting experiments using linear and nonlinear advection schemes based on cloud motion winds derived from time-sequenced geosynchronous satellite imagery (GOES and GMS) are conducted over three regions of the globe: (1) the Caribbean basin, the Amazon basin, and the peninsula of Korea. The experiments are designed to test the possibilities and limitations of straightforward, satellite-based, quantitative nowcasting techniques. The precipitation calculations are made using a probability matching scheme combining an assigned calibration reference (for this study SSM/I retrievals) and infrared black body temperatures (for this case either GOES or GMS EBBTs). These calculations are applied to both current imagery and predicted imagery, in which predictions are generated by advecting cloud fields ahead in time according to cloud drift winds retrieved prior to the initial time from IR sequence pairs, and extrapolating cloud top temperatures (CTTs) based on the a priori CTT growth (decline) rates. A number of sensitivity tests are carried out to demonstrate the strengths and weaknesses of such scheme for differing convective environments.