改进的SIMHYD模型在黄河源区高寒气候的适应性研究

Study on Adaptability of Improved SIMHYD Model in Alpine Climate Region

气候变暖使得区域水文循环过程加快,尤其在高纬度、高海拔地区,温度升高将使积雪、冰川融水量增加,这将给高寒区的水资源管理带来一定的挑战。以黄河上游的高寒气候区为研究对象,先采用5年滑动平均法从流域干燥指数(P/PET)序列中识别出流域水资源最枯、最丰时段;然后,采用度日因子方法耦合SIMHYD模型,提出一种改进的SIMHYD模型(简称SIMHYD_snow模型);最后,对比评估SIMHYD_snow与传统SIMHYD模型的水文模拟过程,并揭示二者在月尺度水资源量评估上的差异。结果表明,黄河源区水资源整体呈“由丰转枯再转丰”的时程变化特征,1990年代最枯;改进的SIMHYD_snow模型显著提高了非汛期水文模拟精度,且湿润期更优;传统SIMHYD模型低估了非汛期的径流量,高估了汛前径流量。研究结果可为高寒气候区流域水资源量的精准评估提供重要的支撑。

Climate warming accelerates regional hydrological cycle,especially in high latitude and altitude areas.The increase of temperature will increase the amount of snow and glacier melt,which will bring some challenges to the water resources management.In this study,the alpine climate region in the upper reaches of the Yellow River was taken as research object.Firstly,the 5-year moving average method was used to identify the dry and wet periods based on the aridity index(P/PET).Then,the degree-day-factor method was used to couple with SIMHYD model,and an improved SIMHYD_snow model was proposed.Finally,the hydrological simulation process of SIMHYD_snow and SIMHYD model were compared and evaluated,and the differences in monthly scale water resources assessment between them were revealed.The results show that the water resources in the source region of the Yellow River change from abundant to dry and then to abundant,with the driest in the 1990s.Improved SIMHYD_snow model significantly improves the accuracy of hydrological simulation in non-flood period,especially in the humid period.The SIMHYD model obviously underestimates the runoff in non-flood period,but overestimates the runoff in pre-flood period.The research results can provide important practical value for accurate assessment of water resources in alpine climate region.