Influence area determination of rain gauge stations in the coffee region, Caldas department, Colombia

Abstract

According to statistics of DANE (2012), Caldas department has suffered a significant reduction in the coffee planted area; it was 92,000 hectares in 2005 and 79,000 in 2012. However, this crop is still of great importance for the region as it represents about 6% of the provincial gross domestic product (GDP). According to Rojas and Gast (2013), decrease in planted area could be explained by reduction in coffee production in recent years. This reduction was related to wet environmental conditions (excessive rainfall) during last years, and it is largely explained by the presence of four “La Niña” events during this time frame. In order to define the area of action for a weather station in an Andean region, records were used of daily rainfall alone last 25 years, taken from a network with 21 weather stations. Daily data were analyzed by using geostatistics, taking into account the experimental semivariograms to define the range of action of a weather station. Specifically, the concept used was the range, calculated from the experimental semivariogram. Results show that, on average, in the Andean region, a rainfall station has between 6 km of a radius influence (daily data) and 15 km of radius (annual data).