Mequaninta F, Mitikub R and Shimelesc A
This study has been conducted with the aim to analyze variability and extremes of daily values of maximum and minimum temperatures, and precipitation. The future data are downscaled using delta method based on outputs from four global climate models (GCMs). The data are simulated for three future 30 year periods, centered at 2030’s (2010-2039) and 2050’s (2040-2069) and for the two scenarios (A2 and B1). Analysis of the 27 core set of extreme weather indices, which are defined by ETCCDI, is carried out on six selected sites and all the results were reported in detail. In addition comparisons in variability has made between models and values of these indices observed in the base climate period (1981-2010) and values of projected periods. Among precipitation indicators, significant increasing trends in annual total wet-day precipitation, number of heavy and very heavy precipitation days and decreasing trends in consecutive wet days, simple daily intensity index and precipitation on extremely wet days were found. Yet, the trends show no spatial coverage. In contrast to precipitation indices, the results indicate that most temperature indices showed significant changes in majority of stations. Nevertheless, the trends show less spatial coherence except cold days and summer days indicators. Regionally, summer days and tropical nights showed significant increases while warm nights, cold days and warmest day showed significant decreases during the base period. On the other hand, for the projected climate, while summer days and warm days would significantly increases but coldest day and cold days would decrease on regional level. The observed decreasing changes in warm extremes (i.e., warm night and warmest night) which are inconsistent with a warming planet and the heterogeneous behavior identified in most temperature extreme indicators suggested that local factors may play a major role in the study area.