Annual and monthly precipitation trends: An indicator of climate change in the Caribbean region of Colombia

This study aims to analyze trends in annual and monthly precipitation in the Caribbean region of Colombia as an indicator of the effects of climate change over the last few decades. Currently, there is no evidence that such a study has been conducted at the regional level in this zone. Therefore, we evaluated precipitation data from 60 rain gauges and assimilated data from the CHIRPS database in 6 departments within our study area. We also used the modified Mann-Kendall and Theil-Sen estimator for trend analysis. We examined the monthly average vertically integrated moisture flux divergence (VIMD) to understand precipitation variations and spatial changes better. Our findings show that the region experiences the highest precipitation from August to November, with lower precipitation from December to February. In February, 5 out of 6 departments showed a negative trend up −0.60 mm/year. Conversely, in March and November, there were notable increases in precipitation in Cesar (0.71 mm/year), Bolivar (1.07 mm/year), Cordoba (0.90 mm/year), and Sucre (0.63 mm/year). La Guajira observed an increase in monthly precipitation from August to November, ranging from 0.47 to 1.17 mm/year. Meanwhile, in the department of Magdalena, decreasing trends were observed in the early months of the year, with an increase in monthly precipitation of 1.61 mm/year noted in November. Correlation coefficients above −0.9 demonstrate a strong correlation between rainfall and VIMD. During the wet season, mountainous regions observed a monthly mean VIMD of −36 kg/m2s. Over the 42 years from 1981 to 2023, the mean annual precipitation at La Guajira increased by 3.76 mm/year, while the mean annual precipitation at Cordoba increased by 0.46 mm/year. Notably, 4 of the 6 departments showed no significant downward trend in annual precipitation. The analysis of monthly rainfall in the Colombian Caribbean region revealed both increasing and decreasing trends, indicating a complex and heterogeneous pattern of precipitation behavior. Over 42 years, the annual precipitation in La Guajira increased by 3.76 mm/year, while in Cordoba, it increased by 0.46 mm/year. These findings serve as valuable indicators of local climate changes and will significantly contribute to seasonal forecasting and risk management based on the four-decade period.