The amplification of the ENSO forcing over equatorial Amazon

Abstract

The remote influence of the El Niño-Southern Oscillation (ENSO) strongly manifests over the equatorial Amazon (EA)-including parts of southern Venezuela, Guyana, French Guiana, and Suriname-when there is a large-scale anomalous upper-level divergence over continental tropical South America. Modeling studies conducted in this paper suggest that it is because of the modulation of the local diurnal cycle of the moisture flux convergence, which results in the local amplification of the ENSO signal over the EA. Further, it is shown that the local land surface feedback plays a relatively passive but important role of maintaining these interannual precipitation anomalies over the EA region. © 2009 American Meteorological Society.