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 . 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 Erinç's aridity index. Semi-arid and semi-humid climate types prevailed in Ürgüp, Kirikkale, Develi, Kirşehir and Akşehir 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.
The hydrographic eastern Mediterranean Basin of Turkey is a drought sensitive area. The basin is an important agricultural area and it is necessary to determine the extent of extreme regional climatic changes as they occur in this basin. Pearson's correlation coefficient was used to show the correlation between standardized precipitation index (SPI) and standardized streamflow index (SSI) values on different time scales. Data from five meteorological stations and seven stream gauging stations in four sub-basins of the eastern Mediterranean Basin were analyzed over the period from 1967 to 2017. The correlation between SSI and SPI indicated that in response to meteorological drought, hydrological drought experiences a one-year delay then occurs in the following year. This is more evident at all stations from the mid-1990s. The main factor causing hydrological drought is prolonged low precipitation or the presence of a particularly dry year. Results showed that over a long period (12 months), hydrological drought is longer and more severe in the upper part than the lower part of the sub-basins. According to SPI-12 values, an uninterrupted drought period is observed from 2002-2003 to 2008-2009. Results indicated that among the drought events, moderate drought is the most common on all timescales in all sub-basins during the past 51 years. Long-term dry periods with moderate and severe droughts are observed for up to 10 years or more since the late 1990s, especially in the upper part of the sub-basins. As precipitation increases in late autumn and early winter, the stream flow also increases and thus the highest and most positive correlation values (0.26-0.54) are found in January. Correlation values (ranging between -0.11 and -0.01) are weaker and negative in summer and autumn due to low rainfall. This is more evident at all stations in September. The relation between hydrological and meteorological droughts is more evident, with the correlation values above 0.50 on longer timescales (12-and 24-months). The results presented in this study allow an understanding of the characteristics of drought events and are instructive for overcoming drought. This will facilitate the development of strategies for the appropriate management of water resources in the eastern Mediterranean Basin, which has a high agricultural potential.
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