January/February 1999 Mesoscale Reanalysis of the WETAMC/LBA-TRMM/Brazil campaign in Rondonia/Brazil

The data assimilation module of the Regional Atmospheric Modeling System (RAMS) was operationally used during the summer 1999 WET/AMC LBA - TRMM/Brazil field campaign in Rondonia/Brazil located in the southern portion of the Amazon Basin in the transition from the forest to pasture. The analysis was performed with a course grid with 80 km resolution and a fine grid of 20 km over the area of interest. Nudging towards the NCEP analysis was applied at the borders of the coarse grid and very week nudging was maintained during the assimilation cycle. The scheme was stable and provided realistic estimates of the low level flow during the campaign. The significant stratiform precipitation during the early phase of the experiment, dominated by the presence of the SACZ, and the transition to prevailing convective precipitation was adequately captured by the mesoscale reanalysis. The diurnal variation of the low level flow as well as of the precipitation were also reasonably reproduced by the mesoscale reanalysis. Preliminary results of the energy and water balances will also be presented.