气候和流域特征变化对淮河流域地表水文过程的影响

定量认识和理解气候与流域特征变化对淮河流域地表水文过程的影响，可以为科学管理淮河流域水资源提供重要的理论参考和技术支撑。评估了多控制因子联立求解归因方法的适用性，以此量化了淮河流域气候和Budyko参数n对不同年代蒸散发(ET)、径流变化(较基准期1961—1980年)的贡献，并且进行了归因分析，结果表明：1)多控制因子联立求解法可以准确有效地分离气候和参数n对ET和径流变化的贡献。2)在气候和参数n变化的共同影响下，20世纪80年代、90年代的ET和径流在沂沭泗河各水文分区均呈减小趋势，而在上游和中游各水文分区的变化则表现出明显的时空差异性。3)就各年代控制ET变化的主要因子，多数水文分区为参数n,其次为降水和潜在蒸散发(PET),分别集中在沂沭泗河地区和淮河上游。20世纪80年代，中游水文分区径流变化的主控因子为PET,其他水文分区则多为降水；而20世纪90年代和21世纪初多数水文分区的主控因子为参数n,其次为降水。总之，控制淮河流域ET和径流变化的物理机制具有明显的空间差异和年代际变化特征。

Impacts of climate and catchment property changes on land-surface hydrological processes in the Huai River Basin, China

To quantitatively understand impacts of climate and catchment property changes on land-surface hydrological processes in the Huai River Basin (HRB), China, can provide important information and theoretical basis for scientifically managing water resources in this region. We firstly evaluated the reliability of a new separation method to estimate contributions of climate (i.e., precipitation and potential evapotranspiration) and catchment property (i.e., Budyko parameter n) to changes in evapotranspiration (ET) and runoff (relative to the period of 1961-1980) in the HRB. Then, the estimated contributions of each factor by the new separation method were used to conduct the attribution analyses. Results showed that (1) both the qualitative and the quantitative validation measures indicated that the new separation method could efficiently and accurately estimate impacts of climate and parameter n on the ET and runoff changes. (2) Under the combined impacts of changes in climate and parameter n, both the reductions of ET and runoff were detected during 1980s and 1990s over the hydrological divisions (HDs) of Yi-Shu-Si River Basin (YSSRB). In the HDs of the upper (UHRB) and middle reaches (MHRB) of the HRB, the ET and runoff changes were characterized by evident decadal and spatial differences. (3) For the changed ET during each period, most of HDs corresponded to the dominants of parameter n, followed by precipitation and potential evapotranspiration (PET), which were respectively located in YSSRB and UHRB. In 1980s, the dominant factor of the changes in runoff over the HDs of MHRB was generally PET, while precipitation as the major contributor appeared in most of the remaining HDs. Most of HDs showed the dominant of the 1990s and 2000s runoff changes to be parameter n, followed by precipitation. To sum up, the physical mechanisms controlling changes in the ET and runoff over HRB existed obvious differences at space, and changed from period to period.