Index-based assessment of long-term precipitation pattern from multiple observation stations in central Ethiopia.

Climatic studies through rainfall histories play a major role in human health impact, economy, and environment of developing countries like Ethiopia. Twenty six years (1995-2020) of rainfall data for about 46 locations were taken into account to evaluate the current research. Three potential rainfall indices such as coefficient of variation (CV), rainfall anomaly index (RAI), and standardized precipitation index (SPI) have been selected to study the climatic condition of the central plateau. Most of the locations (about 50%) had CV results exhibiting extreme rainfall variability (CV > 30) in the northern and southern regions which covered 44% of the study area. Eight distinct climate intensity classes were determined based on SPI and RAI values (wet/humid to dry/drought). According to the RAI, the climate has been relatively dry (49% area). Most of the areas became very dry climate regions according to RAI of less than - 3. The SPI method indicated that both Metahara and Sagure experienced various degrees of drought (from mild to extreme drought), while Metehara never experienced wet weather. The SPI value, which varied from 3.27 (the most) to - 0.66 (the least), illustrated the variety of climatic conditions. The middle section (from northeast to southwest) demonstrated mild dryness, severe to extremely dry conditions, and moderate to high rainfall variation (SPI = [- 1.5 to <  - 2], RAI = [- 0.99 to 0], and CV = 20 to > 30). As a consequence, the northern peak area witnessed the highest variance in rainfall and the most severe drought, with SPI = [- 2 to - 1.5], RAI = [< - 3], and CV =  > 30]. This study demonstrates the significance of these investigations for future climate change studies along with additional meteorological factors in the region.