The effect of using digital satellite imagery in the LAPS moisture analysis

Abstract

The Local Analysis and Prediction System (LAPS) analyzes three-dimensional moisture as one component of its system. This paper describes the positive impact that simple 8-bit, remapped, routinely available imagery have on the LAPS moisture analysis above 500 hPa. A variational method adjusts the LAPS moisture analysis by minimizing differences between forward model-computed radiances and radiances from Advanced Weather Interactive Processing System (AWIPS) image-grade data from Geostationary Operational Environmental Satellite 8 (GOES-8). The three infrared channels used in the analysis will be routinely available to AWIPS workstations every 15 min. This technique improves LAPS upper-level dewpoint, reducing dewpoint temperature bias and root-mean-square error on the order of 0.5 and 1.5 K, respectively, as compared to Denver radiosonde observations data. Furthermore, it strongly exemplifies the objective analysis benefit of image-grade data, in addition to its well-known subjective utility.