Assessing the evidence of climate variability in the northern part of Ethiopia

In semi-arid highlands of northern Ethiopia, episodes of droughts of varying severity and duration occur. The occurrence of these droughts is associated mainly with the seasonal rainfall variability. This study attempts to investigate the temporal and spatial variability of climate parameters, particularly rainfall and temperature for the period 1954-2008. Standardized rainfall anomaly was used to examine the temporal characteristics of climate variability and determine the prevalence of droughts. Analysis of variance was also employed to establish significant differences in rainfall characteristics amongst different in-situ stations. The baseline climate data from each station was also spatially interpolated using ordinary kriging technique. The temporal analysis indicated an overall slight decrease in rainfall and an overall increase in the mean annual minimum and maximum temperatures over the study period. The analysis further revealed that the average annual minimum temperature over the region has been increasing by about 0.72ºC every ten years while average annual maximum temperature has been increasing by about 0.36ºC per decade. This shows that the northern part of Ethiopia is warming faster than the national average of 0.25ºC per decade. It is also observed that the average annual minimum temperature is increasing faster than average annual maximum temperature, which is an indication of warming nights over the years.