New developments for the use of microphysical variables for the assimilation of IASI radiances in convective scale models
Martinet, Pauline ; Fourrié, Nadia ; Guidard, Vincent ; Rabier, Florence ; Montmerle, Thibaut ; Brunel, Pascal ; Lavanant, Lydie
The main purpose of this paper is to assess the feasibility of adding cloud profiles (ql,qi) in the control vector of a 1D-Var assimilation system preparing for the direct assimilation of such profiles in the three-dimensional variational data assimilation (3D-Var) system of the French operational AROME model (Seity et al 2011). To prepare the 1D-Var, an observation-screening procedure permitting an improved selection of homogeneously covered scenes from IASI observations was developed. The feasibility of using cloudy fields from mesoscale NWP models to simulate cloudy radiances was investigated. To that end, the fast RT model RTTOV has been used to improve the simulation of multi layer clouds. We evaluated the simulated cloud-affected radiances and their departures from observations. Finally, some 1D-Var experiments, using cloud-affected IASI radiances are presented.
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