Annual and seasonal patterns of rainfall variability over Venezuela

Heterogeneous Distribution of Rainfall and Discharge Regimes in the Ecuadorian Amazon Basin

“…They report two rainy seasons (February-May and October-November) in the highlands and a first dry season (June-September), which is much more pronounced than the second one around December. A similar cycle with two maxima in AprilMay and October-November and two minima in December-January and July-August can also be observed in the Andes in Venezuela and Colombia (Pulwarty et al 1992;Poveda 2004). The semiannual cycle of rainfall in the Andes results from the latitudinal oscillation of convection maximum that depends on the annual cycle of temperature and insolation (Kousky et al 1988;Horel et al 1989;Figueroa and Nobre 1990).…”

Oceanic influence on the precipitation in Venezuela under current and future climate

“…Sequera (2009) found that El Niño is one of the most important mechanisms for the climate variability in Northern South America. Pulwarty et al (1992) came to a similar conclusion and further suggested that La Niña increases rainfall amounts during the rainy season and over Maracaibo during July-August. La Niña is suggested to have a stronger influence than the El Niño and favors higher precipitation at the coast (Cárdenas et al 2002;Cárdenas et al 2003).…”

“…The rainfall in these areas is bimodal with peaks in May-June and September-October with dry spells July-August and November-April (Pulwarty et al 1998). This bimodal distributions is controlled by the annual cycle of convection over northern South America (Pulwarty et al 1992). In this study a third rainfall regime is described based on larger mean annual rainfall amounts than in the rest of the stations, but it is essentially a unimodal seasonal pattern.…”

Solar modulation of Little Ice Age climate in the tropical Andes

“…One possible explanation for this difference is an antiphasing of precipitation between coastal Venezuela (near the Cariaco Basin) and the Venezuelan Andes. For example, 20th-century Venezuelan climate records show that rainy-season precipitation anomalies have opposite signs in coastal and Andean regions (40). This finding suggests the possibility that, during the LIA, positive rainfall anomalies in the Andes were accompanied by negative anomalies in coastal drainages entering the Cariaco Basin.…”