Spatio-temporal precipitation change assessments over Turkey

The availability of water, and its quality, are among the chief growing concerns that are expected to cause serious questions over the sustainability of the Mediterranean region especially under the present climate change impacts, in general, and over the water resources of Turkey, in particular, due to precipitation pattern variability and sensitivity at arid and semi-arid regions within the country. In order to assess climate impacts concerning precipitation over Turkey, expected spatio-temporal changes are examined by considering precipitation time series at 165 stations across the country covering the period from 1961 to 2008 for almost 5 decades. Methodologically, homogeneity and Mann-Kendall rank correlation trend tests are applied at each station for the identification of statistically significant trends. Long-term annual precipitation averages indicate a decreasing trend with some oscillations during the last 5 decades. However, in more refined periods, average precipitation decreased during 1968-1973 and 1998-2008, whereas it increased during 1973-1981 and 1989-1998. As a result, there is a significant decrease of about 12, 13, and 35% at all stations in annual, rainy period, and winter season total precipitations, respectively. On the other hand, increases occurred at 4, 3 and 19% of all stations in annual, rainy, and autumn season, respectively.