淮河流域水文非线性多水源时变增益模型研究与应用

基于传统时变增益模型(TVGM),进一步考虑地下径流退水,在传统TVGM只考虑单一地表水源的基础上,添加地下水源模块,对地表地下径流分别进行产、汇流计算,改进并提出了多水源TVGM,并将其应用于淮河流域蚌埠闸以上13个水文站控制的代表性子流域。结果表明:多水源TVGM既继承了传统TVGM以简单结构描述复杂水文非线性系统关系的优点,同时通过增加地下水源模块,大大提高了洪水预报的精度。13个子流域参数率定期和模型验证期中,传统TVGM分别有9个和7个子流域达到乙级洪水预报标准,而多水源TVGM分别提高到12个和8个,其中以大型流域和大水年改进效果尤佳。传统TVGM水量平衡系数为0.88,多水源TVGM提高到0.95,平均提高了7%。洪峰模拟相对误差也由传统TVGM的50%达标率提高到多水源TVGM的92.3%,整体提高了42.3%。因此,多水源TVGM能更好的应用于淮河流域洪水预报工作。     

长江中下游流域旱涝急转事件特征分析及其与ENSO的关系（英文）

During recent decades,more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities,which have significant implications on water and food security.To better identify the characteristics of flood-drought alternations,we proposed a modified dry-wet abrupt alternation index(DWAAI)and applied the new method in the middle and lower reaches of the Yangtze River Basin(YRB-ML)to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alternation(DWAA)events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015.We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960.In particular,the DWAA events mainly occurred in May and June in the northwest of the YRB-ML,including Hanjiang River Basin,the middle reaches of the YRB,north of Dongting Lake and northwest of Poyang Lake.In addition,we also analyzed the impact of El Ni?o Southern Oscillation(ENSO)on DWAA events in the YRB-ML.The results showed that around 41.04%of DWAA events occurred during the declining stages of La Ni?a or within the subsequent 8 months after La Ni?a,which implies that La Ni?a events could be predictive signals of DWAA events.Besides,significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events,particularly for the Poyang Lake watershed and the middle reaches of the YRB.This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.