基于Copula函数的绕阳河流域降水事件危险性评估

利用1961—2021年绕阳河流域周边8个气象站的逐日降水资料，以降水持续时间和降水强度作为判断降水事件的两个要素，运用Copula函数确定降水事件的联合概率和重现期，并构建危险性评估模型，分析绕阳河流域降水事件危险性空间特征。结果表明：绕阳河流域周边不同地区降水事件的持续时间和降水强度的最大值存在显著差异。Lognormal和Logistic函数对两个降水要素的拟合效果较好，Clayton函数适合反映两要素联合下降水发生的概率。随着降水持续时间和降水强度的增加，极端降水事件的危险性快速升高；不同地区降水事件的概率和重现期存在着显著差异，阜新站降水持续7 d，强度达到60 mm的事件每10 a出现一次，而盘锦站和北镇站发生持续6 d以上的降水事件较少，多为20 a一遇；降水事件危险性高值区处于绕阳河流域南部，主要位于盘锦、辽中和北镇。

Hazard assessment of precipitation events in Raoyang River basin based on Copula function

Based on the daily precipitation data of 8 meteorological stations around the Raoyang River basin from 1961 to 2021, and considering the two elements of precipitation duration and precipitation intensity, the joint probability and recurrence period of the precipitation events were estimated using were determined using the Copula function, the risk assessment model was constructed, and the spatial features of the risk of precipitation events in the Raoyang River basin were discussed. The results showed that the maximum values of the two elements at different areas presented significant differences. The Lognormal and Logistic functions on the two elements presented good fitting effects, and the Clayton function was suitable for reflecting the probability of precipitation under the combination of the two elements. As precipitation duration and intensity enhanced, the risk of extreme precipitation events increased rapidly. The probability and return period of precipitation events at different areas showed significant differences. The precipitation of Fuxin station lasted for 7 days, with intensity of 60 mm which occurred once every 10 years, while the precipitation events lasting for more than 6 days were less at Panjin and Beizhen station, which mostly happened once every 20 years. The high risk areas of precipitation events were located in the south of Raoyang River basin, mainly in Panjin, Liaozhong and Beizhen.