Contribuição do aninhamento do modelo Eta no modelo de circulação geral atmosférico e acoplado oceano-atmosfera do CPTEC na previsão do clima de verão sobre a América do Sul e Atlântico Tropical / Contribution of nesting regional eta model in atmospheric and coupled ocean-atmosphere general circulation model in seasonal forecast over South America and Tropical Atlantic

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

This work aims to verify the advantage of nesting Eta model in global coupled ocean-atmosphere model (CGCM) in climate forecast over South America and Tropical Atlantic. Three ensembles hindcasts of ten summer (December, January and February) between 1997 and 2006. The hindcasts consist of two global models from CPTEC, one atmospheric (AGCM;T062L28) and another coupled ocean-atmosphere (AGCM and MOM3) and two hindcasts of Eta regional model (40 km and 38 levels) nested into the two global models. The results showed that, in general, the average patterns of the evaluated variables of the global models did not exhibit significant differences between them, which also occurred in the patterns of Eta model nested in these two global models. Therefore, it is suggested that the lateral boundary conditions have more effect than lower boundary conditions of sea surface temperature (SST). The CGCM had produced a cold SST bias between the two bands of precipitation generated by the CGCM and Eta model nested in the CGCM. This bias may have contributed to the formation of the double like ITCZ. The Eta model reduced the excessive latent heat flux generated by global models. In general, the patterns of the Eta model had agreed more to the observations than the patterns of the global models, except for the incoming surface shortwave radiation. For this variable had negative bias, partly caused by errors in the forecast of the low/warm clouds. Comparison against PIRATA buoys observation showed that the Eta model nested in the CGCM resulted in smallest precipitation forecast error. Although the Eta model has generated smaller errors, the global models presented the best results in evaluation of signal-noise ratio.

ASSUNTO(S)

padrões espaciais de verão global coupled ocean-atmosphere modeling dynamic downscaling signal-noise ratio summer spatial patterns modelagem global acoplada oceano-atmosfera downscaling dinâmico buoys of pirata project razão sinal-ruído bóias do projeto pirata

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