Avaliação do impacto das condições hídricas do solo no início da estação chuvosa de 2004/2005 / Evaluation of the hydric soil conditions role on the 2004/2005 rainy season onset

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Some studies have been showed that the surface heat fluxes are important to the monsoon system around the world. The importance of the soil moisture on seasonal forecasts has also been pointed out. Therefore, the influence of the soil moisture on the early stages of the South America (SA) monsoon system was the aim of this study. Moreover, it is aimed to know if anomalously soil moisture condition would lead to either a later or an earlier date of the beginning of the rainy season or to drier or wetter precipitation conditions at the beginning of the rainy season. Four sensitivity experiments using regional Eta model were performed to achieve this purpose. Soil moisture anomalies (+-40%) were induced in the initial conditions of the surface moisture upon two different regions of the SA. The first one is the Amazon region, which is considered very important because a great part of moisture associated with the convection on the monsoon region came from this region. The second one is the central SA, which has been considered the core of the SA monsoon system in previews studies. These sensitivity experiments were performed to the beginning of the 2004/2005 monsoonal rainy season, which was considered to have an onset rainy season date close to the climatological onset date. It was also noted that anomalously soil moisture condition almost did not affect the date of the beginning of the rainy season. On the other hand, these anomalies do affect the surface heat fluxes and precipitation in the tropical SA. The induced anomalously wet (dry) soil moisture condition in Amazon region led to a above (below) precipitation over the Amazon region and a below (above) precipitation over the South Atlantic Convergence Zone. The induced anomalously wet (dry) soil moisture condition in central SA led to a above (below) precipitation over central SA.

ASSUNTO(S)

fluxo de calor à superfície américa do sul precipitação modelo regional eta south america surface heat fluxes monsoon system soil moisture umidade no solo precipitation regional eta model sistema de monção

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