基于Copula函数的东江流域3大水库丰枯遭遇分析

东江流域在广东省政治、经济和社会中占有重要地位,域内新丰江、枫树坝和白盆珠3大水库的来水量直接影响区域生产生活供水.面对水库群联合调度新要求,本文利用Copula函数构建了3大水库入库流量的二维和三维联合分布,分析其丰枯遭遇概率,主要结论如下:(1)3大水库两两间丰枯同步的概率大于丰枯异步的概率,非汛期丰枯同步的概率大于汛期.其中,白盆珠与新丰江、枫树坝丰枯异步的概率相对较大,这为其与另两个水库丰枯互补提供了可能;(2)三维联合分布显示,3大水库丰枯同步的概率在全年、汛期和非汛期均较大,依次为42.29%、41.74%和51.99%,其中同丰和同枯的概率远大于同平的概率.枫树坝与新丰江对下游具有补偿能力的概率分别为29.81%和23.03%,不具有补偿能力的概率分别为32.75%和22.32%;(3)利用3大水库的联合分布,可获得各水库不同入库流量遭遇的概率以及特定概率下各水库入库流量的可能组合,对3大水库联合优化调度具有重要的理论与实践价值.

Study of the wetness-dryness encountering of inflow of the three biggest reservoirs in the Dongjiang River basin based on Copula functions

Dongjiang River basin holds an important political, economic and social status in Guangdong Province. The three biggest reservoirs, namely Xinfengjiang(XFJ), Fengshuba(FSB) and Baipenzhu(BPZ), provide most water for living and production in the basin. Considering the critical requirement of joint operation of multi-reservoirs, this paper constructed 2-dimensional and 3-dimensional joint distributions of inflow of the three biggest reservoirs based on Copula functions, and analyzed their wetness-dryness encountering probability. The results showed:(1) the synchronous wetness-dryness probabilities of any two reservoirs are higher than the asynchronousones,and the synchronous wetness-dryness probabilities in flood seasons are higher than those in non-flood seasons. The synchronous wetness-dryness probabilities of BPZ and XJF, or BPZ and FSB are relatively small, which offers the possibility of wetness-dryness compensation between BPZ and the other two reservoirs;(2) the 3-dimensional joint distribution indicated that the synchronous wetness-dryness probabilities of the three reservoirs in flood season, non-flood season and annual scale are 2.29%, 41.74% and 51.99%, respectively, with the probability of synchronous wetness and dryness much larger than that of synchronous normal ones. The probabilities that FSB and XFJ are able to compensate their lower basin are 29.81% and 23.03%, respectively, while that they cannot do are 32.75% and 22.32%, respectively;(3) By the joint distributions constructed above, we can get the probabilities of any inflow combinations of the three reservoirs, as well as diverse inflow combinations under certain probabilities.