Seasonality of Rainfall in Colombia

Abstract

The knowledge of the annual cycle of rainfall is of primary concern for many socioeconomic activities such as agricultural planning, electricity generation, and flood and other disaster management. The annual cycle of rainfall in Colombia has been studied so far using monthly or quarterly information, identifying zones with the unimodal regime (one wet season and one dry season) over the Caribbean, the Amazon, and the Pacific regions and zones with the bimodal regime (two wet and two dry seasons) in the Andes. This paper explores the annual rainfall cycle in Colombia on a daily basis using historical records of 1,706 rain gauges and the Climate Hazards Group Infrared Precipitation with Station data precipitation data set. We found four types of annual precipitation regimes: unimodal, bimodal, mixed, and aseasonal. The unimodal regime predominates in the low‐altitude zones of the east and the north, the bimodal and mixed regimes over the Andes mountain range, and the aseasonal in the Pacific region. These results improve the statistical diagnosis of the spatial variability of the rainfall seasonality in Colombia. This phenomenon, however, is still far from being fully understood in its hydroclimatic context. The annual migration of the Intertropical Convergence Zone is not enough to explain the diversity of rainfall regimes in Colombia. Local factors such as topography and land cover could play an important role in the occurrence and duration of rainfall seasons.

Amplified risk of spatially compounding droughts during co-occurrences of modes of natural ocean variability

“…We primarily use precipitation from the widely-used high-resolution (0.25°× 0.25°) Climate Hazards group Infrared Precipitation with Stations (CHIRPS version 2) dataset (1981 to present). The CHIRPS daily precipitation dataset has been used for the assessment of daily, monthly, seasonal, and annual precipitation characteristics in several regions of the world [65][66][67][68] . CHIRPS blends satellite-based precipitation estimates with in situ observations, and models of terrain-based precipitation modification to provide high resolution, spatially-complete, and continuous long-term data from 1981 to present, providing distinct advantages over rain-gauge-based products that include variations in station density or remotely sensed data that have a limited temporal extent 69,70 .…”

Ground validation ofTRMM 3B43 V7precipitation estimates over Colombia. Part I: Monthly and seasonal timescales

“…Regarding when it rains, it is worth noting that 3B43 V7 is able to capture, equally precise, the phase of both the unimodal and bimodal annual cycles of mean precipitation at monthly resolution that coexist all over Colombia (Poveda et al, 2006;Urrea et al, 2019), not only on the pixels shown in Figure 3 but on the 427 validation pixels (not shown). This capability seems to be unaffected by the particularities of each region such as topography, climate, land cover and vegetation, among others.…”

Hydrological responses in equatorial watersheds indicated by Principal Components Analysis (PCA) – study case in Atrato River Basin (Colombia)

“…The high precipitation rates observed are a result of the orographic effects over the moisture coming from the Pacific Ocean (Guzmán et al, 2014;Poveda Jaramillo et al, 2014), which are then generated due to permanent convective activity in the region throughout the year (Zea et al, 2000), as well as the influence of the "CHOCO jet" presents larger magnitudes (Hoyos et al, 2018). This climatic and orographic effect combination is responsible Hydrological responses in equatorial watersheds indicated by Principal Components Analysis (PCA) -study case in Atrato River Basin (Colombia) for the existence of different types of hydrometeorological cycles, in regard to precipitation and to river discharge as well (Urrea et al, 2019).…”