8-12 Eylül 2009 Tarihlerinde Marmara Bölgesi’nde Meydana Gelen Sel Olayının Yağış Analizi

Abstract

Anahtar kelimeler: İstanbul, sel afeti, meteorolojik koşullar, şiddetli yağış, kararsızlık indis değerleri. Abstract: A series of flash floods occurred between 8-12 September, 2009 in Thrace part of the Marmara region, and especially in İstanbul and its vicinity. The region was heavily affected from floods that occurred as a result of thunderstorms with torrential rains that swept the region which received its heaviest rainfall in the last 80 years The events were noted as the third deadliest floods after the 1957 Ankara and 1995 İzmir floods.. The floods led to the death of at least 32 people and caused extensive damage to both public and private properties in the region. This study examines climatology of rainfall conditions that led to the flash floods in theThrace part of the Marmara region, and especially İstanbul and its vicinity. The spatial and temporal distribution of the rainfall indicated that the severe storms first affected the western parts of the Marmara region and then covered the entire İstanbul, Silivri and Çatalca where the impact was felt most severely. The 24-hr rainfall amounts mostly varied between 100-253 mm in the region during those 4 days between 7-10 September 2009. The highest 24-hr rainfall amounts were recorded at Bandırma, Çatalca, Erdek, and Silivri stations with 253 mm, 205 mm, 170 mm, and 128 mm respectively. Average rainfall for the Marmara region was 74.1 mm considering the 4-day cumulative rainfall recorded between 7-10 September 2010. This amount is considerably over the long term normals for month of September, which is 36,3 mm. It is noted that almost all the instability indices values signalled severe weather situation and storm development prior to the flooding. Areal distribution of the severe rainfalls are portrayed better with the radar and satellite images analyzed for the flooding days in İstanbul and vicinity.