Climate change impacts on extreme rainfalls over Rize Province, Turkey

Providing a catchment-scale comparison between two GCM-RCM combinations, namely ECHAM5- RegCM3 and CCSM3-RegCM3, this paper investigates the effect of the A2 greenhouse gas emission scenarios on the variability of extreme rainfalls over Rize Province, Turkey. For this aim, firstly, three rainfall-borne climatic statistics have been defined to evaluate the efficiency of each GCM-RCM combination. Then, using different probability distributions, a grid-based comparative analysis between projected design storms at three future levels (2040, 2070, and 2099) and those of reference period (1961- 1990) has been accomplished. The intercomparison results indicated that ECHAM5-RegCM3 provides higher performance than CCSM3-RegCM3 for annual maximum rainfall reproduction. Based upon A2 emission scenario, up to 40% decrease in the magnitude of 100-year design storm is projected for different portions of the province. The results also demonstrated that the best distribution model for characterizing the historical extreme events is not necessarily the best for those of projected extreme events