Spatiotemporal analysis of drought by CHIRPS precipitation estimates

Abstract

<title>Abstract</title> <p>Drought is one of the most devastating worldwide natural hazards that can occur in all climatic zones and cause considerable losses affecting many water-needing sectors. It is also one of the most complex and least understood hazards due to its high heterogeneity in space and variability in time. Therefore, for a proper spatial and temporal drought analysis, spatially dense and uniformly distributed ground-based precipitation data are needed. In practice, such data are generally lacking either due to missing data or to the nonuniform and scarce spatial distribution of ground stations. This gives a great potential to the Climate Hazards Group Infrared Precipitation with Station (CHIRPS) data with a long period and high resolution for using in drought studies. The CHIRPS data also allow to tackle with the problem of sparse, unevenly distributed and erratic ground stations. Based on the CHIRPS data, the study aims to assess the drought condition over Kucuk Menderes River Basin in the western part of Turkey. The analysis was performed considering the seasonality as well as the spatial and temporal change in the drought characterization based on the Standardized Precipitation Index (SPI) calculated at 3-month (seasonal) time scale. Results showed that the CHIRPS and ground stations were highly correlated except for summer despite the overall good performance in the basin. The CHIRPS can properly capture drought characteristics. Droughts have a within-year variability in time and an insignificant variability in space over the basin while the over-year variability shows a significant decreasing trend which could be a signal for more severe droughts after being accumulated over years in the future. The study demonstrates the usefulness of CHIRPS in drought analysis due to the fact that ground-based data are still not at a level dense and long enough to understand the process precisely both in time and space.</p>