Influence of atmospheric and oceanic indexes on interannual precipitation in San Ramon, Costa Rica

Abstract

The interannual climatic variability of precipitation in San Ramón (El Estero stream micro-basin) and its relationship with indexes of the ONI (Oceanic Niño Index), MEIv2 (Multivariate ENSO Index, version 2). CLLJ (Caribbean Low Level Jet Index), the NAO (North Atlantic Oscillation Index), and the SOI (Southern Oscillation Index). To calculate the interannual variation of precipitation, the mathematical analysis program Geogebra in its version 4 and the interquartile range (IQR) were used. Confidence intervals were established to observe the different intensities of ENSO, and precipitation was correlated with the different oceanic-atmospheric indices, showing a negative relationship in four of them and a positive relationship in only one. The NAO index shows a very low regression. With the ONI, the relationship with ENSO episodes was established, showing some relationship during La Niña (cold phase), producing above-average rainfall in the area under study. While during the El Niño event (warm phase) there have been decreases in precipitation.

Keywords

• Climate variability
• ENSO
• Geogebra
• correlation
• oceanic and atmospheric indices