INTERANNUAL VARIABILITY OF UPPER-TROPOSPHERE WATER-VAPOR BAND BRIGHTNESS TEMPERATURE

A method for the intercalibration of the high-resolution infrared soun der (HIRS) upper-tropospheric water vapor band brightness temperature data is developed and applied to data from 1981 to 1993. Analysis of t he adjusted anomaly time series show the location and strength of both the large-scale ascending and descending circulations in the Tropics as well as water vapor anomalies. Comparison of these HIRS data with o utgoing longwave radiation and sea surface temperature anomalies revea ls that both convection and increased upper-tropospheric moisture occu r over anomalously warm water in the deep Tropics. The development and movement of deep convection and increased upper-tropospheric moisture can clearly be traded during the El Nino/Southern Oscillation warm ev ents. These HIRS data are particularly useful in monitoring upper-trop ospheric water vapor variability between the Tropics and subtropics.