气候变化对洪水频率和洪峰流量的影响

Impacts of Climate Change on Flood Frequencies and Peak Discharges

以月平均流量和月最大洪峰流量的相关关系为基础，建立了洪水频率评价模型，并用非参数方法估计各级流量的条件概率。利用月水量平衡模型求得未来不同气候变化情况下的月均流量过程，并探讨气候变化对洪峰流量及洪水频率的影响。东江和汉江部分流域的应用结果表明，降水变化对洪水频率和洪峰流量的影响要比气温变化对其的影响敏感得多，气温升高２℃，降水增加１０％～２０％，２年一遇的洪水频率要相应增加１９．１％～４７．４％；２０年一遇的洪峰流量要增加１０．２％～２４．１％。

Based on the relationship between monthly mean discharges and maximum flood peaks, a flood frequency assessment model is established, and nonparametric method is used to estimate the conditional probabilities of each discharge class. Using the monthly water balance model, the sensitivity of flood frequencies and discharge peaks for changing climate conditions have been analyzed and tested. The results indicate that flood frequencies and peak discharge are more sensitive to precipitation variation than to the temperature increase. In Dongjiang and Hanjiang river basins, temperature incerase 2℃ and rainfall changes between plus 10%～ 20%, the occurrence of a two-year flood frequency will increase from 19. 1% to 47. 4%, annual maximum peak discharge which return period is 20 years will increase from 10. 2% to 24. 1%.