Spatial variations of climate indices in Turkey

The present study explores the spatial variability of the continentality, oceanity and aridity indices in Turkey. Climatic indices are diagnostic tools used to describe climatic conditions and the state of a climate system. In this study, four indices were calculated using the climatic data from 229 meteorological stations in Turkey. The nature of the indices expresses general climatic features such as continentality, marine influences and aridity. The climatic indices used here are the Johansson Continentality (JC) Index, the Kerner Oceanity Index (KOI), the De Martonne Aridity Index (I_DM) and the Pinna Combinative (PV) Index. Furthermore, aridity characteristics in Turkey have been examined using the two separate periods (1960-1990 and 1991-2006). To assess the temperature and precipitation patterns in Turkey, the climatic indices were calculated by using monthly temperature and precipitation for the period 1960-2006. According to the results of the KOI, marine climates characteristics were dominant in the Black Sea region than in its Aegean and Mediterranean region. The JC index is used for the climatic classification between continental and oceanic climates. The continental effect was found across 25% of the country. The maximum continentality with a score of 71.5 has been found in the eastern Anatolia. Furthermore, semi-dry areas were increasing in the 1991-2006 period compared to 1960-1990. A significant correlation was found between the values of the JC index and the KOI. The JC index gives reasonable results for Turkey. The continental effect was found across 25% of the country. This analysis may be of benefit for the explanation of landscape characteristics and the rational utilization of water resources, agriculture and energy scenarios for the region in many areas of Turkey.