Case study on the distribution of precipitable water associated with local circulation using the split-window data of a NOAA satellite

Abstract

The algorithm of Iwasaki (1994 a) to estimate precipitable water over land was applied to 12 analysis units of a 30 x 30 array of pixels (about 33 km x 33 km at the nadir point for NOAA satellites) including mountainous regions, and retrieved volume was compared with microwave radiometer data. The correlation between satellite and radiometer precipitable water was 0.81, slope and the y interception of the regression line are 1.08 and -1.68 mm, respectively. Using the algorithm, the mesoscale distributions of precipitable water and its time change associated with thermally induced local circulations were visualized under the cloud-free conditions. Precipitable water on the coast increased by 5-20 mm from morning to afternoon. At the same time, precipitable water increased by 0-20 mm over the mountains and decreased by 0-15 mm at the foot of the mountains.