El Nino-Induced Tropical Droughts in Climate Change Projections

Autor(es)

Coelho, Caio A. S. ^[1] ; Goddard, Lisa ^[2]

Afiliação do(s) autor(es)

^[1] Inst Nacl Pesquisas Espaciais, Ctr Previsao Tempo & Estudos Climat, SP RJ, BR-12630000 Cachoeira Paulista, SP - Brazil

^[2] Columbia Univ, Earth Inst, Int Res Inst Climate & Soc, New York, NY - USA

• Tipo de documento: Artigo Científico
• Fonte: Journal of Climate; v. 22, n. 23, p. 6456-6476, DEC 1 2009.
• Citações Web of Science: 29

Resumo

El Nino brings widespread drought (i.e., precipitation deficit) to the tropics. Stronger or more frequent El Nino events in the future and/or their intersection with local changes in the mean climate toward a future with reduced precipitation would exacerbate drought risk in highly vulnerable tropical areas. Projected changes in El Nino characteristics and associated teleconnections are investigated between the twentieth and twenty-first centuries. For climate change models that reproduce realistic oceanic variability of the El Nino-Southern Oscillation (ENSO) phenomenon, results suggest no robust changes in the strength or frequency of El Nino events. These models exhibit realistic patterns, magnitude, and spatial extent of El Nino-induced drought patterns in the twentieth century, and the teleconnections are not projected to change in the twenty-first century, although a possible slight reduction in the spatial extent of droughts is indicated over the tropics as a whole. All model groups investigated show similar changes in mean precipitation for the end of the twenty-first century, with increased precipitation projected between 10 degrees S and 10 degrees N, independent of the ability of the models to replicate ENSO variability. These results suggest separability between climate change and ENSO-like climate variability in the tropics. As El Nino-induced precipitation drought patterns are not projected to change, the observed twentieth-century variability is used in combination with model-projected changes in mean precipitation for assessing year-to-year drought risk in the twenty-first century. Results suggest more locally consistent changes in regional drought risk among models with good fidelity in reproducing ENSO variability. (AU)

• Processo FAPESP: 06/02497-6 - Um sistema integrado de previsoes climaticas para a america do sul.
• Beneficiário: Caio Augusto dos Santos Coelho
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 05/05210-7 - Um sistema integrado de previsões climáticas para América do Sul
• Beneficiário: Caio Augusto dos Santos Coelho
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores