نوع مقاله : مقاله پژوهشی
نویسندگان
گروه مهندسی آب، دانشگاه تبریز، تبریز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
One of the important consequences of climate change on extreme floods is the change in frequency, time of their appearance and their amount.In this research, the seasonality of flood in the Urmia Lake basin was analyzed based on the extreme flood data of 14 stations. This work was done using the new method of circular statistics in the statistical period of 2003-2019. The uniformity of occurrence time of extreme floods(OTEF) was examined by Rayleigh-test and Kuiper-test, in significance levels of 0.1, 0.05 and 0.01. The slope of the trend lines for the OTEF were estimated using the modified Sen’s estimator. The results of the Kuiper test indicated that there is no uniformity in the OTEF. It was found that there are two distinct flood seasons in the region including a) late March to mid-May(S1) and b) mid-September to early December(S2). The mean of seasonal strength index of events was equal to r ̅= 0.695. After dividing the year into the mentioned two seasons, this figure was 0.9 for the first season and 0.78 for the second season. These two parts of Urmia Lake had same seasonality strength in the S1. However, seasonality of the western part of the lake was stronger than the eastern part in S2. In the S1, on average, in 40% of the stations, the OTEF had a negative trend and the rest had a positive trend (60%). This figure for the S2 season was 11% for the negative trend and 78% for the positive trend, respectively.
کلیدواژهها [English]
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