Análisis de los índices extremos de precipitación en Colombia y su relación con el fenómeno ENSO

Abstract

Objective : The main purpose of this study was to understand seasonal variations in the intensity, frequency and du- ration of extreme precipitation events in Colombia (Case study in Choco department), during the period 1982-2015, based on a set of 6 selected precipitation indices calculated from stations’ daily dat, for the June-July-August . Materials and Methods : The analysis of extreme events in Colombia was carried out, using extreme precipitation indexes, calculated from the data set of the World Precipitation Climatology Center.Trend analysis of the indices was carried out using Mann-Kendall nonparametric test, and Sen’s slope estimator was used for calculating the magnitude of trend. Results : The spatial patterns in all the extreme precipitation indices indicated mixed trends on the Pacific region and the Piedemonte Llanero. The wet indices show a non-homogeneous positive trend, but the dry indices show a general negative trend in Colombia. Teleconnection patterns associated with the Pacific Ocean have a negative impact on the wet indices, but a positive one the maximum number of consecutive dry days. In the department of Choco, positive tendencies of the consecutive dry days were found in municipalities such as: Acandi, Jurado, Litoral del San Juan and Sipi, and negative tendencies in the municipality of the centre of the department, for example Quibdo and Istmina. Conclusions : The teleconnection patterns of the Pacific Ocean have caused droughts, while on the Atlantic Sea, the rainfall indices have suggested wetter conditions during the last four decades and an increasing number of heavy rainfall events. In the department of Choco, the municipalities on the Pacific coast and in the North have a tendency to increase extreme drought events, but the municipalities in the centre of the department have positive trends in the wetter conditions associated with extreme rainfall events.