HR: 15:10h
AN: GC13B-07    [Abstracts]
TI: Diagnosing El Niño Induced Drought in Seasonal Forecasts and Climate Change Projections
AU: * Goddard, L
EM: goddard@iri.columbia.edu
AF: International Research Institute for Climate & Society, The Earth Institute at Columbia University, 61 Route 9W, P.O. Box 1000 228 Monell Bldg., Palisades, NY 10964, United States
AU: Coelho, C A
EM: caio@cptec.inpe.br
AF: Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), Rodovia Presidente Dutra, Km 40, SP-RJ, Cachoeira Paulista, SP 12630-000, Brazil
AB: El Nino brings widespread drought to the tropics. Stronger or more frequent El Niño events in the future will exacerbate drought risk in already highly vulnerable areas. Even if the frequency and intensity of El Niño events do not increase in the 21st century, more generalized warming of the tropical Pacific may still produce a tropical teleconnection resembling that associated with present-day El Ni~o conditions. In this work, the patterns, spatial extent, and severity of El Ni~o induced tropical droughts are evaluated for a control period in the 20th century in seasonal forecasts, which have updated realistic initial conditions but fixed greenhouse gases (GHGs), and climate change projections, which have realistic GHG evolution but no observational updates. We examine the strengths and weaknesses of the model responses to large scale changes in sea surface temperature (SST) such as those due to ENSO or to climate change. The concern is that if the impact on precipitation fields from anomalous SST forcing on seasonal timescales is poorly simulated in climate change projections, then the impact on such precipitation fields from increasing greenhouse gas forcing cannot be trusted either. More optimistically, if the models contain robust information, and differences are due mainly to systematic biases, then the predictions/projections can be spatially recalibrated to provide more confident estimates of near-term and longer-term drought risk within the tropics. The results have implications for 21st century projected changes in the strength of the identified patterns of tropical drought.
DE: 1637 Regional climate change
DE: 1812 Drought
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3374 Tropical meteorology
DE: 4522 ENSO (4922)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting