Retrieving atmospheric temperature profiles by microwave radiometry using a priori information on atmospheric spatial-temporal evolution

A new approach is presented to determine atmospheric temperature profiles b y combining measurements coming from different sources and taking into acco unt evolution models derived by conventional meteorological observations. U sing a historical database of atmospheric parameters and related microwave brightness temperatures, we have developed a data assimilation procedure ba sed on the geostatistical Kriging method and the Kalman filtering suitable for processing satellite radiometric measurements available at each satelli te pass, data of a ground-based radiometer, and temperature profiles from r adiosondes released at specific times and locations. The Kalman filter tech nique and the geostatistical Kriging method as well as the principal compon ent analysis have proved very powerful in exploiting climatological a prior i information to build spatial and temporal evolution models of the atmosph eric temperature field. The use of both historical radiosoundings (RAOBs) a nd a radiative transfer code allowed the estimation of the statistical para meters that appears in the models themselves (covariance and cross-covarian ce matrices, observation matrix, etc.). We have developed an algorithm, bas ed on a Kalman filter supplemented with a Kriging geostatistical interpolat or, that shows a significant improvement of accuracy in vertical profile es timations with respect to the results of a standard Kalman filter when appl ied to real satellite radiometric data.