Verificação do modelo de circulação geral da atmosfera do CPTEC/COLA: ciclo hidrológico e processos de superfície / Verification of the global model circulation atmospheric of CPTEC/COLA: hydrological cycle and surface process

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The verification of surface processes and hydrological cycles obtained in the climate simulation experiment using the COLACPTEC atmospheric general circulation model, forced by the monthly mean sea surface temperatures, is conducted. The simulated climate is obtained from the 12-month average of a set of four 15-month integration?s. The verification is made through comparison of model results with climatological values in different spatial scales (global, regional, and grid points) and temporal scales (annual, seasonal, and monthly). The results show that the model effectively captured major patterns of global precipitation, such as ITCZ , SPCZ, and SACZ and the zones of low precipitation such as the Sahara desert and the regions associated high-pression centers over the oceans. The proposed model also satisfactorily represents the surface and subsurface flow (runoff) in terms of annual and global mean values. However the model overestimates the precipitation and evapotranspiration. Besides our model produces excessive rainfall rates in the regions of high topography and lower rainfall rates in other regions for example the ITCZ region, a common characteristic in most general circulation models (GCM). The model overestimates the incident solar radiation and the net radiation at the surface due to weak solar radiation absorption by the atmosphere. However, the surface air temperature is underestimated, probably due to the high evapotranspiration rate. The latitudinal distribution of the components of energy and hydrological balances is well represented, captured by the model. The runoff, when analyzed for the most important global basins of the world, presents consistent discrepancies with the precipitation discrepancies, with the exception of the high latitude rivers and La Plata River. The results indicate that the model overestimates the precipitation over the major part of the Brazilian territory, during the summer except over the Amazon region, where it is underestimated. The precipitation in southern Brazil, which is mainy produced by frontal system activity, is underestimated.

ASSUNTO(S)

modelos meteorology models radiação planetária surfaces hydrological cycle floresta úmida ciclo hidrológico camada limite atmosférica planetary radiation atmospheric bondary layer meteorologia rain forests Área albedo albedo

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