Spatial and temporal characterization of droughts in Central America - evaluation of five drought indices

Central America is characterised by a large spatial and temporal climate variability and is frequently affected by extreme events with sometimes severe negative consequences to livelihoods, economy and environment. In particular, droughts have large impacts on agriculture and hydropower, but even so, studies characterizing their extent and connection to the regional climatic variability remain scarce. We evaluated the applicability of five drought indices in Central America by analyzing their capability to characterize the spatial and temporal variability of droughts. The indices included in this study were the Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, Effective Drought Index, Percent Normal and Deciles. Since the observational data in the region are often scarce and uncertain, the computation of the indices was done using different meteorological data sets based on gauged and/or satellite precipitation and temperature data. The use of the different data bases met a secondary objective: to evaluate the capability of available meteorological data sets to represent the complex climate of the region. The data sets used to calculate the drought indices were TRMM, CRN073, CIGEFI-UGR, ERA-INTERIM, Pedreros and CRU, each of them with their own spatial and temporal resolution. The Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index and Effective drought Index behaved similarly both in timing and spatial extent of droughts but the severity varied among them. The Percent Normal Precipitation and Deciles did not seem to be applicable in Central America since they got affected by the strong seasonality of regional precipitation