Evaluating Probability Distribution Functions for the Standardized Precipitation Evapotranspiration Index over Ethiopia

Drought indices are used to identify and monitor drought events. The standardized precipitation evapotranspiration index (SPEI) is a widely based on accumulated water balance. There is, however, no broad consensus which probability distribution the most appropriate for balances. This issue investigated Ethiopia using 125 meteorological stations spread across country. Based long-term series, selection was made among generalized extreme value, Pearson type 3, logistics (Genlog) distributions. Additionally, effect of actual, instead potential, limited amount data (10, 15, 20, 25 years) explored. Genlog found be best all accumulation periods. Furthermore, there considerable difference amongst SPEI values estimated from three distributions identification wet or dry Next, significant differences between actual (SPAEI) SPEI, signifying importance proper monitoring. Finally, time series 20 years lead almost similar those more than 30 data, so could potentially assess in Ethiopia.