Adjustment of the Standardized Precipitation Index (SPI) for the Evaluation of Drought in the Arroyo Pechelín Basin, Colombia, under Zero Monthly Precipitation Conditions

The evaluation of the meteorological drought is fundamental for management water resource. One most used indices to evaluate standardized precipitation index (SPI) due its practicality and in a variety time scales, however, this uses as only variable, depending on deviations values. This important when evaluating SPI, because some ecosystems close equatorial zone, there are very warm periods with low rainfall, which large proportion data collected by stations corresponds zero. In research, SPI was calculated Pechelín basin located Colombia, zero data, registering month January February 67% 70% respectively. As result, values increased “wet” ranges, amount exceeded half total data; means that determines wrong it zero-precipitation proportions. Based finding, study aims modify typing distribution (using correction factor K), finally correcting values, called SPI-C. results indicate SPI-C improved identification drought, obtaining corresponding better represent high frequency existing area.