Climate Change in Gilgel Abbay Catchment Upper Blue Nile, Northwestern Ethiopia

Abstract

Gilgel Abbay catchment, is one of cereal producing area of Ethiopia, where its productivity is entirely dependent on climatic conditions. This study was aimed at assessing climate change for the last 30 years on this important catchment. Rainfall and temperature data obtained from the catchment stations were used to examine the changes in climate. The mean annual and decadal rainfall and temperature were analyzed to evaluate changes over time. The maximum, minimum and coefficient of variations were also calculated to examine the variability within catchment over time in the catchment. The trend for long time was assessed by linear regression; correlation and significance between the recorded climate data were checked by paired sampled t-test. The results have revealed that over the last 30 years there was both declining and variability of rainfall and rise of temperature in the catchment. There was also spatial and temporal variation of rainfall and temperature in the catchment. Those areas of upper catchment with higher altitude have received more rainfall and lower temperature than the middle and the lower parts. There was also seasonal variation in distribution and amount of rainfall and temperature in the catchment. More rainfall was received during the summer season from June-September in the catchment where as higher temperature was recorded on months of April and May.

Keywords: climate change; rainfall; temperature; rainfall variability; catchment; trend of change