Drought analysis using CORDEX simulations over the mediterranean climate regions of Turkey


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2018

Student: ANIL YILDIRIM POYRAZ

Supervisor: İSMAİL YÜCEL

Abstract:

Drought has been a significant result of climate change that causes variance on precipitation regimes. Mediterranean region is one of the hotspots of the world in this respect. Dry summers and rainy winters -the characteristic of this climate type- makes this region more vulnerable to the effects of climate change. Hence, it is important to monitor drought considering the increasing population and economic facilities in the regions that are under Mediterranean climate conditions in Turkey. This study aims to assess the trends in drought by applying the Standardized Precipitation Index(SPI) for 5 timescales – from 1 month to 12 months. The model grid data that corresponds to meteorological stations distributed from south to west within the study area was obtained from 12 different Global Circulation Model / Regional Climate Model couplings of CORDEX project. Observed and modeled prediction data were compared for reference period (1971-2005) in order to detect the most reliable models. Afterwards, modified Mann-Kendall trend test was applied on the SPI and annual precipitation values for the entire period (1972-2100). The trends were estimated by linear regression for the locations in which Mann-Kendall results indicated a significant change. In conclusion, a persistent increasing drought trend was detected for Muğla and western Antalya parts such that all models are coherent. On the other hand, the divergence of the trends for some regions according to different models signifies the discrepancy of models. Besides, the drought trends are decreasing for some regions (especially Southern Marmara) as the timescale increases.