Approach to spatial estimation of meteorological droughts in the Coello River basin, Colombia

The space-temporal evaluation to characterize meteorological droughts was based on data accumulated monthly precipitation between 1996-2005 from 20 meteorological stations distributed in the Coello River basin. Data precipitation was performed preprocessing with data consistency tests to correct and delete data over- or under estimated. To estimate missing precipitation data are compared three geostatistical interpolation methods derived from Kriging, associated with secondary variables such as the Ordinary Kriging, CoKrigin Ordinary associated with secondary variables of a Digital Elevation Model and data satellite TRMM. To select the statistical method the setting of each interpolation was compared with respect to three reference stations through three quality tests, which were Root Mean Square Error (RMSE), Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). In this investigation two of three tests favor the Ordinary CoKriging using as a secondary variable Altitude (COK+DEM). With the interpolated series of precipitation were evaluated and characterized by drought Standardized Precipitation Index (SPI) at monthly and quarterly scale, calculating the parameters of severity, duration, intensity and frequency of droughts. By mapping are delimited the regions where occur the more negative values of SPI. In analyzing spacetemporal the months of January, February, July and August are the driest of the year. In 1997 the meteorological drought greatest damage occurs in the Coello River basin generally concentrated in the middle and lower part of the basin, with a maximum intensity of SPI -2,57.