Assimilation of satellite precipitable water in a meteorological forecast model

Abstract

This preliminary study presents the assimilation method, which is based on optimal interpolation, and results of analysis and forecast runs over 12 h for one case. The Special Sensor Microwave/Imager (SSM/I) radiometer (the scanning microwave radiometer aboard the US Navy Defense Meteorological Satellite Program satellite) and the Prevision a Echeance Rapprochee, Integrant des Donnees Observees et Teledetectees (PERIDOT) model (operational limited-area model of the French Meteorological Office) were used to perform this test. We show that assimilation of SSM/I data has a significant impact on the forecast, since the resulting fields, especially the humidity field, are more coherent with the next SSM/I data and radiosonde observations. The SSM/I assimilation is performed first once only, then throughout a 24-h assimilation cycle. -from Authors