Temporal and spatial variation characteristics of runoff processes and its causes in Huaihe Basin

Abstract

径流变化特征及成因研究对于农业灌溉、流域水资源配置与管理等具有重要理论与现实意义，而淮河流域是我国重要农业区，因而淮河流域径流过程特征及机理研究更突显其重要性.利用非参数Mann-Kendall趋势检验和小波转换等方法系统分析了淮河中上游息县、王家坝和蒋家集等9个水文站点径流资料，分析淮河流域中上游径流年内分配、年际变化、径流趋势、突变特征及周期变化等径流过程变化特征，并探讨了径流变化特征的成因.研究发现：①淮河中上游径流量主要集中于5-9月，约占年径流总量的70.37%，变差系数介于0.16~0.85之间，径流年际极值比则介于1.7~23.9之间，径流年际变化剧烈；②淮河中上游径流量整体呈下降趋势，尤其是4-5月径流下降趋势显著，季节变化不明显；③各站点年径流量在2000s呈显著周期变化，班台、王家坝、鲁台子和蚌埠站在该尺度上存在2.0~3.4 a尺度的小周期，息县、潢川和蒋家集站处于高能区.季节和汛期与非汛期的显著周期集中出现在1960s、1980s和2000s，1960s周期主要为2~8 a.④潢川站年径流量对气候因子的响应最为明显，其对混合ENSO指数和太平洋中高纬年代际振荡指数（PDO）的响应分别通过了95%和99%的显著性检验.PDO对各站点月径流的直接影响最为显著，且主要集中在6月份，多呈显著负相关关系，以班台站最为显著，分别在1、4和6月通过了95%的显著性检验.南方涛动指数、北大西洋涛动指数和Nino3.4区海表温度距平指数（Nino3.4）对研究区月径流量的响应存在显著滞后性，Nino3.4对研究区月径流量滞后期的影响主要发生在潢川和蒋家集站，而北极涛动指数和PDO指数无滞后性响应.;The study on runoff variation characteristics and genesis is of great theoretical and practical significance for agricultural irrigation and water resource management. The Huaihe Basin (HRB) is an important agricultural area in China. Therefore, its characteristics and mechanism of runoff are very important. The runoff data from the nine hydrological stations in the middle and upper reaches of HRB are analyzed in its distribution, abrupt change characteristics and cycle variation, and the causes of runoff variation characteristics. It is found that the runoff of the middle and upper reaches of HRB accounts for about 70.37% of the total runoff from May to September, with the variation coefficient between 0.16 and 0.85, and the inter-annual extreme value ratio between 1.7 and 2.3. The runoff fluctuates in the middle reaches of HRB, and the trend of the runoff in the middle and upper reaches of HRB is decreasing, especially the runoff in April and May is significant and the seasonal variation is not obvious. The annual runoff of each site is significantly changed in 2000s. The runoffs in stations Bantai, Wangjiaba, Lu Taizi stations have a small cycle of 2.0-3.4 years. The runoffs in the county, Huangchuan and Jiang Jiake stations were in the high energy area. The seasonality of flood in gand non-flooding periods are mainly in the 1980s and the 1960s. The response of the annual runoff to the climatic factors in Huangchuan Station is the most obvious, with significance of 95% and 99% for Multivariate ENSO Index and Pacific Decadal Oscillation (PDO) indices, respectively. The direct impact of PDO on the monthly runoff of each site was the most significant and mainly concentrated in June with a negative correlation. The results showed that the response of Southern Oscillation Index, North Atlantic Oscillation and the Nino3.4 sea surface temperature (Nino3.4) to the monthly runoff in the study area was significantly delayed, and Nino3.4 had a significant effect on the monthly diameter of the study area. The effect of the lag period is mainly in Huangchuan and Jiangjiaji, while the Arctic Oscillation and PDO indices have no lag response.