Change in Precipitation and Temperature Amounts over Three Decades in Central Anatolia, Turkey

Abstract

The study presents the change in precipitation and temperature of the Central Anatolia region which a semi-arid climate prevails. The climatic data consists of the monthly rainfall totals and temperatures from 33 stations in region for the period of 1975-2007. The spatial distribution, the inter-seasonal and the inter-annual amounts of rainfall were studied, along with the vulnerability of Central Anatolia to desertification processes and the place of this semiarid region. Annual temperature frequency has been calculated and shows significant increase in temperature of approximately 2.6% corresponding to 0.4?C. The change in climate was determined according to Erin?’s aridity index. Semi-arid and semi-humid climate types prevailed in ürgüp, Kirikkale, Develi, Kir?ehir and Ak?ehir between 1975 and 1990. However, arid and semi-arid conditions prevailed in these stations after 1990. The decrease of the mean rainfall intensity (MRI) has varied between 0.3% and 21% annually since 1990. Decreases in seasonal rainfall intensity (SRI) and annual rainfall totals are found generally in the south, east and southeast of the region. Increases in SRI and annual rainfall totals are observed in the north and northwest of the region however, these increasing percentages are not as great as the decreasing percentages. Rainfall series have been analyzed for long-term trend according Mann-Kendall test. Results of this test indicate that a decreasing trend of winter and spring rainfall intensity is evident, whereas a generally increasing trend is observed for summer and autumn rainfall intensity. These changes began in the late 1970s and early 1980s across most of Central Anatolia.