Abstract
Seasonal reversal of the ENSO rainfall signal in the Philippines
International Research Institute for Climate and Society, Earth Institute, Columbia University Lamont Campus, Palisades, New York, USA
Philippine Atmospheric, Geophysical and Astronomical Services Administration Central Office, Quezon City, Philippines
Philippine Atmospheric, Geophysical and Astronomical Services Administration Central Office, Quezon City, Philippines
Philippine Atmospheric, Geophysical and Astronomical Services Administration Central Office, Quezon City, Philippines
Philippine Atmospheric, Geophysical and Astronomical Services Administration Central Office, Quezon City, Philippines
Seasonal rainfall in the Philippines is known to be modulated by the El Niño Southern Oscillation (ENSO) phenomenon, with ENSO warm (cold) events frequently contributing to drought (excessive rainfall) in many areas. Here, using rainfall data from 40 observing stations across the Philippines, it is shown that the seasonal rainfall response to ENSO reverses sign between boreal summer (July–September) and fall (October–December) for both El Niño and La Niña. Above-median, boreal summer rainfall is observed at several stations in the north-central Philippines during El Niño before anomalously dry conditions become manifest the subsequent fall. Conversely, during La Niña below-median summer rainfall occurs at several stations before the onset of anomalously wet conditions in fall. The results are shown to be not simply a consequence of ENSO transitions during boreal spring, but are associated with changes in the large scale monsoon system during the life cycle of ENSO events.
Received 14 September 2006; accepted 22 November 2006; published 29 December 2006.
Citation: (2006), Seasonal reversal of the ENSO rainfall signal in the Philippines, Geophys. Res. Lett., 33, L24710, doi:10.1029/2006GL028182.
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