Short term climate trend and variability around Woliso, Oromia Region, Central Ethiopia

Abstract

Based on the meteorological data of Woliso for the last decade (2004-2013), short-term climate variability was assessed. Computation were made to identify mean monthly, seasonal and annual temperature patterns and deviations, linear trends and R² values, rainfall coefficient, rainfall intensity, water surplus and deficit, and moisture region of Woliso area. The findings showed the presence of almost uniform pattern of both temperature and rainfall. The temperatures showed significant decrement in its minimum and increment in its maximum, and mean annual temperature by about -0.3, +1.28, and +0.49 ⁰C, respectively over the last decade. Similarly, seasonal variability were identified with increment in the winter, summer and autumn by 1.13, 2.78 and 0.9 ⁰C, respectively while it showed decrement in the spring by -0.5 ⁰C. About 60% of the years (2004, 2005, 2008, 2009 and 2011) experienced low rainfall intensity while 40% of them (2006, 2007, 2010 and 2013) had medium rainfall intensity. The only year which experienced extreme rainfall intensity was in 2012. Six months (ONDJFM) were dry (low RC <0.6),  whereas May and September received big rains  with moderate concentration (rainfall coefficient =1.0-1.9) and the summer (JJA) received big rainfall with high concentration (rainfall coefficient=2.0-2.9). The climate type of Woliso was under Dry sub- humid (C1) that also requires further water development schemes to supplement the life and livelihood especially during the dry months. However, such findings should be scrutinized as the current report used only a decade’s data.

Keywords: Climate Pattern, Variability, Rainfall, Temperature, Trend