Spatial Characteristics of Drought Propagation from Meteorological to Hydrological Drought over Ethiopia
Abstract
Devastating droughts are common in Ethiopia, impacting the livelihoods of the community. Ethiopia's government and aid organizations are trying to advance an early warning system to predict and monitor the drought events; however, constraints of observed meteorological and hydrology data cause difficulties. We used CHIRPS and Global Runoff Data Center (GRDC) gridded data from 1984 to 2014 to analyze the spatial drought characteristics and propagation period from meteorological to hydrological drought over Ethiopia. The standardized precipitation index ( SPI) at timescale 1,3,6,9,12,18 and 24 months are used for meteorological drought and the standardized runoff index (SRI) at a 1-month time scale for hydrological drought. The changes in SPI and SRI and their relationship for the last three decades are explored using a non-parametric Mann-Kendal trend and Pearson correlation test at each grid point. The long-term pattern of meteorological and hydrological drought is increasing in most countries. The southern part for SPI and southeast for SRI show a higher and significantly increasing trend. The spatial drought propagation result shows that for SPI-1, SPI-3, and SPI 6, the country's central highlands show the highest correlation with SRI-1indicating drought propagation from meteorological to hydrological over those are shorter than in western and southeast lowlands areas, which is relatively highest correlation 0.4 to 0.6 values with SPI-9 and SPI-12. Generally, the spatial analysis shows drought propagation time from meteorological to hydrological is highly influenced by basin characteristics; highland areas quickly ( 1 to 6 months ) transfer to hydrological drought, and lowland areas relatively take a more extended period ( 9 to 12 months), but arid climate aggravates the impact.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.A46E..12K
- Keywords:
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- Ethiopia;
- Drought;
- SPI;
- SRI;
- Drought propagation