Evolving Climate Classification of East and Central Oromia in a Changing Climate Using the Koppen–Geiger Method

For efficient management of water-related assets, agricultural planning, lowering disaster risks, for educational and urban planning, it is essential to determine climate types. The modified Köppen climate classification of East and Central Oromia was examined in this study, along with shifts in climate type and spatio-temporal variability from 1991 to 2020. This study basis updated rainfall and temperature data from local meteorological stations, in contrast to earlier research that mainly relied on global datasets to characterize climate types at national and global scales. The study area's distinct climatic diversity is a result of its complex topography, which includes highlands, midlands, and natural forest areas. A statistical approach applied to determine Köppen climate types across the study area. The study results determined three major climates groups-tropical, temperate, and arid-and additional the seven sub-climate types identified. The wet, warm summers and dry winter climate dominate the west, central, and east parts of the study area of Shewa, Hararge and Arsi highland areas. The semi-arid steppe (hot) climate type prevails in the Eastern areas. The research finding further observed that the Aw, BSh, Cwb and BWh climate types increased by 2.3%, 1.1%, 0.3% and 0.2% of total land area, respectively. In contrast, Cfb, Cfa and Cwa climate types decreased by 4.1%, 0.3% and 0.1% of the total land area, respectively. This trend indicates long rainy periods have become shorter compared to previous periods. From the study finding, observed changes reveal a shift from cooler and more humid temperate climates toward warmer and drier climate types, suggesting an expansion of long dry and cold-season areas across the study area.