RAINFALL AND TEMPERATURE VARIABILITY CHANGE AND ITS LINK WITH NINO3.4 and SOI

Abstract

Climate variability is unstable, varying erratically on global, regional, and local scales. Knowledge of past climatic variability at local and regional sizes can aid in the development of adaption strategies. As a result, a study was carried out and developed to examine past spatial and temporal variability, as well as changes in climate variables in the Eastern Hararghe during the last 38 years. The study is based on gridded station and satellite rainfall and temperature data from 1983 to 2020 for rainfall and 1981 to 2018 for temperature. The spatial distribution of rainfall and temperature was examined using ArcGIS 10.5 software. Mann-Kendall (MK) and Sen's slope estimator trend tests were also employed to analyze rainfall and temperature trends. Pearson correlation was used to examine the relationship between seasonal rainfall and global climate signals. The findings in the Eastern Hararghe zone show that rainfall variability has been larger in the northeast of the research area, in the outermost areas of Harar city, and slowly decreasing in the western part. Annual rainfall had a statistically negligible negative trend of 0.10 mm/year (p > 0.05). However, there has been minimal to significant geographic variability of rainfall anomaly in the area. The seasonal anomaly of the minimum temperature trend has shown a considerable increase in the eastern section of the Zone over the previous 38 years. The mean seasonal temperature detected an increasing anomaly trend in the zone's northwestern and northern parts. The seasonal variability is caused by the global indices ENSO (NINO3.4) and SOI. Overall, the erratic rainfall, rising temperatures, and the highest regional variation perceived in the zone suggest that the area's agricultural sector is vulnerable and requires the attention of all actors to save agriculture production in Ethiopia's Eastern Hararghe Zone. To develop an effective strategy for climate change adaptation, it is necessary to xiii understand the existing effects of climate on economic growth as well as extreme climate.