A climate change impact: Variation in precipitation patterns, and increased drought risk in Turkey

Abstract

Since the industrial revolution, temperature averages have been changing both in local and global scale. These variations are related with the climate and global warming changes. Such typical changes (i.e., increasing heavy precipitation, and declined light or total precipitation) are also observed in Turkey. As expected, decreased precipitation usually promotes drought conditions, and can cause extended dry days or periods. Thus, strong relationship can be considered between precipitation scarcity and drought conditions. In this study, changes in precipitation (i.e., total, bottom/lowest and extreme 10%), dry days length, dry spells (>6 days) and drought severity risk based on Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were evaluated quantitatively over Turkey from 1971 to 2000 with regards to climate changes. Trend analysis is performed by using Innovative-Şen analysis (ITA) method to evaluate trend behavior of precipitation, lengths of dry days and spells. Results show that changes in dry days (?DD/?T) converge to (-2% ±3%)/0C, while changes in prolonged dry spells change (?DS/?T) are comparatively higher (3% ±5%)/0C. For precipitations, mean values of ?P/?T converges to constant value as (-6% ±8%)/0C, (0% ±2%)/0C and (-1% ±4%)/0C for total, top 10% heavy and lowest 10% precipitations, respectively. These changes are supported by ITA outputs. All results support and point out that prolonged drought risk frequency and severity has been increasing.