Spatial characterization of drought through CHIRPS and a station-based dataset in the Eastern Mediterranean

Drought is a natural hazard which occurs in all climatic zones and affects different sectors such as irrigation, energy, water supply, and ecology. Monitoring and predicting drought are pressing challenges since drought is becoming more common and severe owing to the impacts of climate change and increased climatic variability. However, in many areas of the globe, the temporal and spatial characterization of droughts and trends in their frequency and severity is hindered by a lack of reliable, long-term locally measured data and unevenly distributed, erratic meteorological stations. In this situation, remote sensing datasets such as Climate Hazards Group InfraRed Precipitation with Station Data (CHIRPS) can offer valuable insights into long-term developments and the spatial characteristics of droughts. Nonetheless, it is often uncertain to which extent data such as CHIRPS succeeds in representing local dynamics and how this varies between geographical regions and climate zones. 

In this analysis, we aim to evaluate spatial drought conditions over the Seyhan River basin in Turkey in the Eastern Mediterranean. Using the Standardized Precipitation Index (SPI) as a drought index, the applicability of CHIRPS as a long-term satellite precipitation product for drought monitoring is investigated. We compare two spatial representations of the SPI: one derived on a per-pixel basis from CHIRPS data since 1981, the other based on data from 19 meteorological stations scattered across the basin which was spatialized using inverse distance weighted interpolation. Our results offer insights into the relative accuracy of CHIRPS data in the Eastern Mediterranean, and avenues towards optimizing the quality of spatial drought characterization approaches.