Site-specific intra-annual rainfall patterns: a tool for agricultural planning in the Colombian sugarcane production zone

As in most equatorial zones, in the sugarcane production zone of Colombia (SPZ), a typical rainfall pattern is known, i.e. bimodal. This pattern, in which two rainy seasons alternate with two dry seasons throughout the year, is explained by the marked effect of the intertropical convergence zone (ITCZ) on the climate of the region. Although the referred pattern is true, it has been generalized and idealized, suggesting dry and rainy seasons with similar duration and intensity. A classic intervention analysis was applied to three daily mean time series generated with historical data from 29 locations located in the SPZ to generate the intra-annual rainfall patterns for each location. The series corresponds to the historical climatological scenario, and the other two scenarios correspond to a synthetic El Niño year and a La Niña year. It was found that there are marked differences between the rainfall patterns in the northern, southern and central localities of the SPZ, although the maximum distance between the two farthest localities is only 200 km. The idealized bimodal rainfall pattern is very similar to that of the center of the SPZ but dissimilar to that of the southern and northern zones. The patterns also vary depending on the La Niña or El Niño condition. With this information, zones of differential management of cane crop were defined.