Abstract:

In this study, Erinç’s aridity index was calculated, the climate type of 29 meteorological stations was designated and mapped using the mean temperature and annual precipitation data of in the Seyhan Basin and its surrounding area covering the years 1970-2009. The recorded temperature data have been examined as the period (1970-2009) was divided into two parts: 1970-1992 and 1993-2009. The long term trend of the annual mean temperature, seasonal mean temperature and total annual precipitation were analyzed using the Mann-Kendall rank correlation coefficient test and their trend ratio was also calculated. A statistical significant increase trend in the series of annual temperatures and significant decrease in the series of the annual precipitation 29 meteorological stations were determined. The increase in temperature is shown in whole seasons and the increase in the summer temperature is evident and strong. The autumn and the winter temperatures follow this temperature. Moreover, the decrease trend in total annual precipitation is more evident in the stations situated within the coast and the middle parts than stations situated within the north part (Suşehri, Zara and Sivas). After 1988, a general decreasing trend in precipitation was considerable severe. When changes of the precipitation and temperature accounts are followed from the north to the south of the basin, it is has been seen aridification is more in the middle and south parts and in these parts, water deficit will be more in later years. A trend towards drought was determined in Pınarbaşı, Divriği, Kangal, Elbistan, Mut, Adana, Kozan, Karaisalı, Silifke, Göksun, Afşin ve Gemerek during second period. In addition, arid condition took place of the semiarid condition in Develi, Kayseri and Şarkışla during this period. The increase in aridity index shows that Karataş, Mersin, Ceyhan, Kahramanmaraş, Anamur and Yumurtalık do not under the aridity hazard in the south part. Key words: Seyhan Basin, Temperature trend, Precipitation trend, Climate change, Aridity index.

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