P-20

Study of the impact of satellite data, radiosondes and GPS in a SACZ episode using G3DVar.

L. G. de Goncalves (CPTEC/INPE), and H. Azevedo (CPTEC/INPE)

Earth observations from satellite have great importance and impact, in particular for operational weather and climate forecast centers in the Southern Hemisphere such as the Center for Weather Forecast and Climate Studies. It is well known that such data is critical, in particular over Southern Hemisphere oceans where there is a lack of other information sources, where satellite data provides excellent spatial coverage with relatively frequent sampling in addition to sweeping continents, deserts, woodlands and other remote areas. In continental regions, there is in addition to the impact of radiances, the impact of radiosonde data and GPS. Hence, studies like Observing Systems Experiments where we are able to test whether observational input data in an assimilation system degrades or improves analyzes and forecasts, are of great value. One of the difficulties within the NWP nevertheless, is to predict the correct intensity of severe weather systems, which has great impact on the population. This work aims to study the impact of radiances, radiosondes and GPS assimilated in the Global 3DVar (G3DVar) assimilation system based on the Gridpoint Statistical Interpolation (GSI) in a situation of extreme event, such as the South Atlantic Convergence Zone from January 8th 2013 to January 15th 2013.