The South American Water Balance: The Influence of Low-Level Jets

Autor(es)

do Nascimento, Marilia Guedes ^[1] ; Herdies, Dirceu Luis ^[1] ; de Souza, Diego Oliveira ^[2]

Afiliação do(s) autor(es)

^[1] Natl Inst Space Res INPE, Ctr Weather Forecasting & Climate Res CPTEC, BR-12630000 Cachoeira Paulista, SP - Brazil

^[2] Minist Sci Technol & Innovat MCTI, Natl Ctr Monitoring & Early Warning Nat Disasters, Sao Jose Dos Campos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Climate; v. 29, n. 4, p. 1429-1449, FEB 2016.
• Citações Web of Science: 7

Resumo

To study the climatology of the water balance over South America and analyze the influence of low-level jets (LLJs), a climate study of the water balance and its main components was performed, specifically in the Amazon and La Plata basin (LPB) region, from 1979 to 2008. The results showed that on average for the analysis period, the Amazon basin and LPB performed as a sink of moisture (ET < P) and as a moisture convergence for the regions, which accounted for approximately 62% and 43% of the precipitation, respectively. During the study period, 884 days with an occurrence of LLJs were observed, occurring most frequently during the winter and around 0000 and 0600 UTC. When considering the water balance for the days with LLJs, it was observed that the Amazon acts as a source of moisture, especially in the dry season, and that the LPB behaves as a sink during all months. The influence of the LLJ as a modulator for precipitation on the LPB is clear, as the precipitation is 32% higher during the LLJ events compared with days without LLJs. This main pattern shows that the moisture convergence trough of the LLJs is crucial for the water balance on the LPB, whereas evapotranspiration is a more important variable of the water balance on the Amazon basin with or without the LLJs. (AU)

• Processo FAPESP: 08/09969-6 - O balanço de umidade na américa do sul: consequências remotas causadas pelo desmatamento da amazônia
• Beneficiário: Marília Guedes Do Nascimento
• Modalidade de apoio: Bolsas no Brasil - Doutorado