The effect of sea surface temperature and deforestation on the mid‐summer drought over Mexico and Central America

Abstract

AbstractWe analyse the effects of deforestation and the projected differential sea surface temperature (SST) anomalies between the tropical North Atlantic and the eastern North Pacific on the mid‐summer drought (MSD) over southern Mexico and Central America. To address these issues, we performed a set of three 6‐year (1996–2001) sensitivity experiments with RegCM4 driven by the ERA‐Interim reanalysis and employing different SST (projected end of century patterns under the RCP8.5 scenario) and vegetation (turning forest landuse into grass) configurations. The model domain follows the specifications of the COrdinated Regional Downscaling EXperiment (CORDEX) for Central America. Results indicate that projected SST patterns cause the MSD signal to almost disappear from the regional mean annual cycle, with its spatial extent decreasing from ~82 to ~48%. In the vegetation sensitivity experiment, the MSD intensity increases along the Pacific coast and Central America, while the MSD spatial extent remains almost unchanged. These regional changes in MSD can be explained in terms of the regional precipitation response to deforestation, primarily due to changes in vertical moisture advection.