Extreme Rainfall Indices Of Ankara: Trends From Historical To Future

Abstract

The frequency and the severity of extreme events arc increasing. In 2019, 935 new extreme events were detected in Turkey, with the most hazardous being heavy rain, floods, and windstorms. Ankara, the capital of Turkey, is one of the affected cities from these events. Understanding the characteristics of these events is crucial because extreme events have significant negative impact on social, physical. and economic environments. In this study,9 extreme-precipitation indices were determined and examined in terms of trends and statistical characteristics for the historical (1950-2015) and future (2015-2090) period at Ankara, Turkey. HadGEM2-ES, MPI-ESM-MR, and. GFDL-ESM2M model results under two representative concentration pathways (RCP), RCP45 and RCP85 scenarios at two grid cells (2733 and 2734) covering four major stations of Ankara were used to obtain future-period precipitation series. Moreover, extreme-value analyses were applied to daily precipitation data of historical (1950-2015) and projected (2050-2090) periods with peak-over-threshold (POT) and block maxima (BM) approaches, and the results were compared. Trend-test results, in general, yielded insignificant trends that were mostly negative. Results of extreme-value analyses show that Grid 2734 return-level values were considerably greater than those of Grid 2733. and variability increased with an increasing return period. Grid 2734 results also exhibited greater values than those of observation-period return levels, while return levels at Grid 2733 exhibited smaller values than the observation-period return-level values.