Seasonal and interannual variations of upper tropospheric water vapor band brightness temperature over the global monsoon regions

The upper-troposphere water vapor (UTWV) band brightness temperature (BT) dataset derived from the High-resolution Infrared Radiation Sounder (HIRS) channel 12 of the National Oceanic and Atmospheric Admini-stration (NOAA) polar satellites from 1979 to 1995 is used to analyze the seasonal and interannual variations for the global monsoon regions. Results show that (i) there are three major regions where the UTWV band BT varies significantly with season, i.e., South Asia, the western coastal South-North America tropical region and the low-lati-tude African region; (ii) UTWV band BT clearly reveals the water vapor temporal / spatial features as well as the at-mospheric circulation structure over the low-latitude during the monsoon onset; and (iii) there is a remarkable rela-tionship between the interannua] variation of the UTWV band BT over the monsoon regions and the sea surface tem-perature anomaly in the eastern equatorial Pacific.