Annual Characterization of Regional Hydrological Drought using Auxiliary Information under Global Warming Scenario

Abstract. Climate change and global warming scenario is likely to increase worsening drought across the World. Drought is a complex natural hazard, which is a composition of many factors such as hydrological, meteorological and agricultural. Accurate characterization of hydrological drought at regional level is challenging. Standardized Drought Indices (SDI) is commonly used method for drought characterization and monitoring. In this study, we proposed a hydrological drought index, which used improved monthly precipitation estimates under global warming scenario. As monthly precipitation records have significant role in regional drought characterization. Therefore, this research suggests auxiliary information as local weights to improve monthly precipitation records in terms of dependence characteristic of temperature with precipitation records under regression estimation settings. Consequently, we proposed a new method of hydrological drought assessment The Locally Weighted Standardized Precipitation Index (LWSDI). We assessed hydrological drought using LWSDI on 10 meteorological stations located in various climatological regions of Pakistan. We compared and evaluated performance of LWSDI with Standardized Precipitation Index (SPI) and Standardized Evapotranspiration Index (SPEI) at 12-month time scale based on Pearson correlation. We found high positive correlation between the LWSDI and existing methods (SPI and SPEI). In summary, improved estimates of precipitation can strengthen drought monitoring system.