Large-scale precipitation and latent heating distributions in the Tropics derived from satellite-borne passive and active microwave sensors

A Bayesian retrieval technique with additional constraints is applied to satellite passive and active microwave sensor measurements to deduce the three dimensional distributions of precipitation and latent heating in the atmosphere. Critical to the success of this technique is the discrimination of convective and stratiform rain regions which are associated with different dynamical and latent heating structures. Observing system simulation studies indicate reasonable agreement between "truth" and instantaneous microwave sensor estimates of rain rate, convective rain proportion, and latent heating vertical distribution.

Instantaneous estimates of precipitation and latent heating from the Special Sensor Microwave/Imager (SSM/I) and the Tropical Rainfall Measuring Mission’s Microwave Imager (TMI) and Precipitation Radar (PR) can be composited over monthly periods in the Tropics to deduce the large-scale patterns. From a prototype algorithm applied to the TMI data from February, 1998, a maximum zonal-mean rain rate of 10 mm/day and a convective rain proportion of 55% associated with the ITCZ were deduced. Also near the ITCZ, the zonal-mean latent heating distribution exhibited a maximum of about 5.5 K/day at 5-6 km altitude and a weak cooling peak at low levels. Analyses of precipitation and latent heating distributions will be presented at the conference.