Downscaling and assimilation of an enhanced data base in Southeastern South America

GARCÍA SKABAR, YANINA; NICOLINI, MATILDE

Foz do Iguaçu, Brazil

Conferencia; 8th International Conference on Southern Hemisphere Meteorology and Oceanography ICSHMO; 2006

American Meteorological Society

The purpose of this work is to produce an enriched analysis for the summer 2002-2003, during which the South American Low-Level Jet Experiment (SALLJEX) was performed. Enriched analyses were generated ingesting all available data following a downscaling methodology, using the Regional Atmospheric Modeling System (RAMS). RAMS model was applied to obtain analysis every three hours, with an horizontal resolution of 80 km covering mostly South America and an enhanced domain with 20 km resolution for the region encompassing Central and Northern Argentina, southern Brazil, Bolivia, Paraguay and Uruguay. The alternatives of vertical coordinates included in RAMS version, sigma-Z and shaved-ETA have been used to generate two different sets of analysis. To evaluate which analysis better represents the "real field", estimated soundings and surface data from the enriched analyses were generated at times coincident with the observations and at grid-points nearest to the stations within the SALLJEX observational network. Root mean square errors (RMSE) were calculated for 15 vertical levels and for each variable. A reduction in the RMSE values was found for all variables and levels and therefore an improvement in representation of data once they were assimilated in the analysis.