Recent Precipitation Trends and Floods in the Colombian Andes

Abstract

This study aims to identify spatial and temporal precipitation trends by analyzing eight extreme climate indices of rainfall in the High Basin of the Cauca River in Southwestern Colombia from 1970 to 2013. The relation between historical floods and El Niño Southern Oscillation (ENSO) is also analyzed. Results indicate that in general, the reduction of precipitation, especially in the center of the basin with negative annual and seasonal trends in intensity indices, namely, the annual maximum 1-day precipitation amount (RX1day) and annual maximum 5-day precipitation amount (RX5day). Sixty-four percentage of the stations exhibit an increasing trend in September–October–November in the consecutive dry days. In December–January–February interval, positive trends in most of the stations is noted for total precipitation and for the number of wet days with rainfall greater than or equal to 1 mm. The findings also show that sea surface temperature (SST) in the equatorial Pacific is statistically correlated (r) with indices of extreme precipitation (r ≥ −0.40). However, the effect of ENSO is evident with a time lag of 2–3 months. These results are relevant for forecasting floods on a regional scale, since changes in SST of the equatorial Pacific may take place 2–3 months ahead of the basin inundation. Our results contribute to the understanding of extreme rainfall events, hydrological hazard forecasts and climate variability in the Colombian Andes.

Statistical Analysis and Stochastic Modelling of Hydrological Extremes

“…Mahmud et al [12] 31 March 2018 2 4 1 1 Rhee and Yang [13] 14 June 2018 2 2 0 0 Khan et al [14] 27 July 2018 2 2 1 1 Mousavi et al [15] 16 October 2018 2 3 1 1 Amnatsan et al [16] 9 November 2018 3 3 0 0 Bafitlhile and Li [17] 6 January 2019 3 3 1 1 Pan et al [18] 22 January 2019 2 2 0 0 Ávila et al [19] 22 February 2019 4 5 2 1 Pham et al [20] 3 March 2019 3 3 1 1 Tung et al [21] 8 March 2019 2 2 0 0 Dawley et al [22] 5 April 2019 3 3 0 0 Zhang and Wang [23] 4 June 2019 2 5 0 0 Mehmood et al [24] 14 June 2019 3 5 0 0…”

“…In a case study for the High Basin of the Cauca River in Southwestern Colombia, Ávila et al [19] examined temporal trends in eight extreme precipitation indicators by the Mann-Kendall (MK) test and the Sen slope estimator for the period 1970-2013. The results showed a decreasing trend in precipitation intensity indices of annual maximum 1-day precipitation amount (Rx1day) and annual maximum 5-day precipitation amount (Rx5day).…”

Streamflow Intensification Driven by the Atlantic Multidecadal Oscillation (AMO) in the Atrato River Basin, Northwestern Colombia

“…The GMFD data result from a combination of the global datasets and reanalysis from NCEP-NCAR reanalysis, Climatic Research Unit monthly climate variables, Global Precipitation Climatology Project (GPCP) daily precipitation, Tropical Rainfall Measuring Mission three-hourly precipitation and the NASA Langley monthly surface radiation budget. This dataset provides a significant improvement over the original reanalysis variables and has been used for a wide variety of applications and diagnostic studies in hydroclimatology [24,60,61]. This data was obtained in the area limited at 65 •…”

“…The simple daily intensity index (SDII) is the ratio between the total annual rainfall and the number of wet days (≥1 mm). These indices have been widely used to quantify severe rainfall and to detect possible relationships between hydrological threats and areas that are potentially vulnerable to catastrophic events [24,[70][71][72][73][74][75].…”

“…The El Niño Southern Oscillation (ENSO) in the interannual time scales is the main ocean-atmospheric coupled phenomenon that affects the rainfall distribution in tropical regions and causes droughts and/or floods in the watersheds involved [15,18,19]. Several studies have documented the ENSO effects on rainfall and streamflow in northern and northwestern South America (SA) [1,18,[20][21][22][23][24][25] with consequent negative impacts on the economy, biodiversity and human health in Colombia [6,25,26]. The ENSO warm phase or El Niño (EN) is associated with negative anomalies of the rainfall, soil moisture, evapotranspiration, and streamflow, mainly in central, northern, and western Colombia [1,20,25,27,28], which are caused by variations in both the Walker and Hadley cells [29][30][31].…”