Simulation of Satellite Passive-Microwave Observations in Rainy Atmospheres at the Meteorological Service of Canada

In this paper, a research version of the Meteorological Service of Canada (MSC) global environmental multiscale (GEM) mesoglobal weather forecasts model is evaluated by comparing the simulated special sensor microwave/imager brightness temperatures (Tbs) with the observed ones. Several comparisons based on two 15-day periods, one in winter and one in summer, have been done. Results are compared to those obtained for a study conducted on the European Centre for Medium-Range Weather Forecast (ECMWF) model. The overall performance of the GEM model is similar to that of the 2001 version of the ECMWF model. The model appears to simulate with realism the large-scale rainy systems but with frequent mislocations. Moreover, the model has a tendency to produce intense small-scale precipitating areas that are not observed. The occurrence frequency of cloud and rain is overestimated by the model. Finally, these results are encouraging enough to continue investigating the assimilation of Tbs in cloudy and rainy skies at MSC.