Climatic variations in Central America and the Caribbean

Resuming earlier work, this study explores the circulation mechanisms of rainfall variations in Central America and the Caribbean during 1921–1986. Regarding interannual variability, correlation analysis shows as favourable for abundant rainfall in the region warm surface waters, low pressure, upward motion, and weak tradewinds on the Atlantic side and over the eastern Pacific enhanced southerlies and a northward displaced intertropical convergence zone. In the course of the twentieth century, the region experienced alternations between protracted and contrastingly extreme regimes of rainfall, from wet 1931–1938 to dry 1939–1947 to wet 1950–1956 to dry 1971–1978. Changes in circulation patterns from the dry to the wet regimes are in the sense of correlations in interannual variability, pattern changes being broadly inverse in the evolution from the wet to the dry regimes. The alternations between contrasting circulation and rainfall regimes are reflected in changing lake levels. The study exemplifies the information value of a novel circulation data set. Copyright © 2012 Royal Meteorological Society