TRAKYA'DA GÜNLÜK YAĞIŞLARIN ŞiDDET BAKIMINDAN OZELLIKLERİ

In this study, the contributions of rain-days of different intensities were developed from 9 stations in Trakya. Days of light rain (< 1O mm) made up 80-85 per cent of the total number of rain-days but contributed only 30-40 per cent of annual total. Days with moderate rainfall (10- 25 mm) made up 15 per cent of the total number of rain-days and contributed more than half the annual rainfall total. Days of heavy and very heavy rainfall made little contribution to the annual total. In ali stations the greatest contribution of the üght rainfall days to the annual total was found in April-May. Rainfall intensity was greatest in September, October and November in Trakya. The spatial distribution of rain-days of different intensities over Trakya shows that rainfall intensities decrease from Black Sea coast to interiors, with a steep gradient over Istranca mountain. The maximum contribution of heavy rainfalls (up to 30 per cent of the monthly total) were found in Black Sea coast of Trakya and north of the Saros Gulf especially U�unuköpril environs. For example, the highest 24 hour rainfall in Trakya, 168.3 mm, occured at Iğneada at the Black Sea coasts. Probable maximum rainfall was estimated using Gumbel statistical technique. According to results, ali stations can recive aproximatly 50 mm. or more rainfall in a day every two years with 57 per cent probability. An analysis of the highest rainfall showed that the probabilty of occurence of 50 mm rainfall in a day increase in November.