The spatio-temporal variability of the precipitation intensity over Turkey

The purpose of this study is to determine the temporal and spatial characteristics of daily precipitation intensity for 1 12 stations in Turkey with the records ranging from 34 to 73 years, within the period of 1930-2002. The study examines the changes of the daily precipitation intensity at individual stations regarding the precipitation regime regions of Turkey. The results of the study were presented by using maps and tables. The homogeneity of the data was checked by Kruskall-Wallis homogeneity test. Mann-Kendall rank correlation coefficient and the less square linear regression methods were applied to these precipitation series in order to determine the trends and changes in the daily precipitation intensity. Results of the trend tests indicated an increasing trend of light precipitation (0-10,0 mm) over most of Turkey in winter, especially in the Black Sea precipitation region. On the contrary, the normal (10,1-25,0 mm) and moderate (25,1-50,0 mm) precipitation showed generally a decreasing trend over Turkey. On the other hand, the Marmara Transition and the Continental Central Anatolia rainfall regime regions showed an increasing trend in the class of moderate precipitation. Because of the high year-to-year variability and the low occurrences of these classes, it is very difficult to interpret the series of the heavy (50,1-100,0 mm) and very heavy (>100 mm) precipitation. Marmara Transition and Continental Central Anatolia rainfall regions showed an increase in annual heavy precipitation series. Very heavy precipitation class was found only on the coastal districts. None of the rainfall regions showed significant trends in very heavy precipitation over the period 1 930-2002.