Hydrology: Current Research

Analysis of Meteorological Drought Using SPI and Large-Scale Climate Variability (ENSO)-A Case Study in North Shewa Zone, Amhara Regional State, Ethiopia

Abstract

Bethel Geremew Shefine

Drought is one of the most complexes and least understood natural disaster that causes loss of life and property destruction. The objective of this study was to analyze meteorological drought using Standardized Precipitation Index (SPI) and climate variability (ENSO) in North Shewa Zone, Amhara Regional State. Spatiotemporal variability or trends of rainfall, and temperature were also analyzed. For the seasonal trend analysis of rainfall, maximum and minimum temperatures the MK test was applied and there have been significant increasing trend in maximum, minimum temperature, mostly in semi-arid district. The rainfall of three agro-ecological zones showed strong variability with negative Sen’s slope indicated decreasing signal mostly for Belg season and semi-arid district. The Belg season rainfall showed high variability. Ataye station Belg season (April and May) dry events occurred in 1999, 2000, 2008, and 2011, while the wet events occurred in 1990, and 1993. In the same station, the kiremt season (June and July) wet years occurred in 1990 and 2010, whereas extreme dry events occurred in 1994, 2000, 2008 and 2011. The Kiremt season dry events years were also much higher in Ataye (semi-arid) district as compred to other district, whereas the wet events years were higher in debre berhan (cool, humid, highlands) district. The major El Nino years were in 1982, 1987, 1997 and 2015, whereas the major La Niña years occurred in 1988, 1999, and 2000. In Ataye station the correlation between Kiremt rainfall and Niño 3.4 was -0.43, while in the Belg season it was 0.53. In most of the years the La Nina was associated with rainfall deficiency in Belg season but increase rainfall in Kiremt season. The contrary was true for El Nino events.