Trend analysis of long-term rainfall and temperature data for Ethiopia

Abstract

ABSTRACT Trend analysis for the long-term average temperature and rainfall of Ethiopia during 1901 to 2015 has been performed to understand the pattern of these important meteorological features under climate change. The rainfall characterizations viz., precipitation concentration index (PCI), seasonality index (SI), rainfall anomaly index (RAI) and departure analysis of rainfall (DAR) have been calculated and interpreted. The annual rainfall recorded for the whole period was 816.3 ± 90.82 mm/year. During kiremt (long rainy) season, maximum seasonal rainfall of 453.2 mm were recorded while, its minimum value (39.6 mm) were received in bega (dry) season, respectively. The analysis of probability distribution for the time series data showed slightly positive skewness and kurtosis in monthly, seasonal and annual rainfall from the normal distribution. The results of Modified Mann–Kendall trend analysis for average temperature revealed a significant increasing trend from 1961 to 2015. Conversely, dry season (bega) rainfall, showed an increasing trend while kiremt season rainfall with decreasing trend for the period of 1901–2015. However, annual and other seasonal rainfall did not show any statistically significant trend. Study concludes that there is an increase in the average temperature in Ethiopia but, it constitutes a high degree of stability in rainfall rate and distribution.