基于Copula函数的流域内降雨丰枯遭遇研究

Study on wetness-dryness encountering probability of basin precipitation based on Copula function

基于Copula函数建立了东江流域上游龙川站、中游河源站和下游博罗站3个站点汛期、非汛期及全年降雨丰枯遭遇发生概率的联合分布模型,计算获得各个时段不同情形下降雨丰枯遭遇的发生概率及条件发生概率。结果表明:3个站点降雨丰枯遭遇在时间尺度上存在差异性,非汛期降雨量不足,调水不利情况最易发生;从年时间尺度看,研究时段内调水不利年份偏多,不利情况发生概率64%。认为规划设计水资源调配方案时,应有针对性地利用水库调蓄水量,合理配置,科学调控,实现流域内水资源高效可持续利用。

Based on the Copula function,a joint distribution model was established to simulate the wetness-dryness encountering probability of precipitation in the flood season, non-flood season,and over a whole year upstream of the Longchuan Station, in the midstream at the Heyuan Station, and downstream of the Boluo Station in the Dongjiang River Basin. With this model, the precipitation wetness-dryness encountering probabilities and conditional probabilities in different scenarios during various periods were calculated. The results show that there are some variabilities in the wetness-dryness encountering probability of precipitation at the three stations. The amount of precipitation was insufficient in the non-flood season,readily causing problems for water diversion. On an annual scale, unfavorable cases for water diversion occurred in most of the study periods, with a probability of 64% . It is suggested that in the planning and design of water resources allocation, reservoirs should be used to rationally allocate and scientifically control water resources,so as to realize the efficient and sustainable utilization of water resources in river basins.