陆面水文模式中冰川次网格参数化方案及应用研究

In western China, glacial melt represents a very significant source of streamflow, especially in arid and semi-arid inland river basins. Over past decades, global warming has resulted in the accelerating melting and universal receding of glaciers, which have had significant impacts on the regional water resources and environment. In order for the sustainable utilization of water resource in the western China, it is essential that the change mechanism and future trend of glaciers and water resource are quantified by hydrological models in high cold mountains regions in western China, as it is in these regions where most of the larger rivers in China acquire their headstreams. Now the runoff generation processes from glaciers are seldom explicitly considered within land hydrology models, so that there are few land surface hydrological model which can meet the goals of hydrological simulation in glacial catchment in high cold mountain area. Considering that, this item will rely on the observation system of Tanggula Filed station. It draws up to modify the glacier energy - mass balance model based on the observed meteorological data, energy data and glacier mass balance data in glacier area, and analyze the spatial distribution characteristics of the meteorological elements based on the observed data from the gradient observation system of field station and the Chinese meteorological stations. On this basis, taking into account both the operating speed and the accuracy of the system simulation, a subgrid glacier parameterization will be developed and implemented into the Variable Infiltration Capacity (VIC) macroscale land surface hydrological model. The model and some parameters will be calibrated and validated by observed glacier mass balance data and remote sensing data. The extended VIC model will be applied to simulate the hydrological processes of the past few decades in the origin of the Yangtze River. The variation characteristics of water cycle elements and their response mechanism to global climate change will be studied based on the simulation and observation.

冰川融水是我国西部重要的水资源，近几十年随着气候变化，冰川呈加速消融趋势，已对区域水资源、生态环境产生了重大影响。利用陆面水文模型，定量评估和预估我国西部高山区流域冰川、径流变化机理及未来趋势，可为制定合理的西部水资源可持续利用对策提供科学依据。本项目针对现有陆面水文模式缺失冰川方案，而不能满足高山冰川流域陆面水文过程模拟需求这一问题，拟依托唐古拉野外观测站，通过冰川区的气象、能量及物质平衡观测，完善冰川能量-物质平衡模型，以气象梯度观测数据结合国家气象站的观测数据，分析气象要素的空间分布特征，在此基础上，以期在大尺度陆面水文模式VIC上耦合一个兼顾运行速度和模拟精度的次格网化冰川方案;以观测的冰川、径流等数据结合遥感数据对模式在流域尺度的陆面水文模拟效果进行检验和参数分析，通过对长江源区流域过去几十年的陆面水文过程进行模拟，结合观测数据，探讨流域水循环要素变化特征及对气候变化的响应机理。

冰川融水是我国西部重要的水资源，近几十年随着气候变化，冰川呈加速消融趋势，已对区域水资源、生态环境产生了重大影响，为制定合理的西部水资源可持续利用对策提供科学依据,有必要定量评估和预估我国西部高山区流域冰川、径流变化机理及未来趋势。陆面水文模式是水文水资源定量评估和预估的重要工具和平台，本项目针对现有陆面水文模式缺失冰川方案，而不能满足高山冰川流域陆面水文过程模拟需求这一关键科学问题，开展陆面水文模式中冰川次网格耦合方案研究。首先依托唐古拉和老虎沟野外观测站，通过典型冰川区的气象、能量及物质平衡观测数据，开展了冰川消融模型（能量平衡及度日因子）的验证与对比研究，表明在流域或区域尺度的模拟研究中，度日因子消融方案仍然是一个较好的选择；在此基础上，在大尺度陆面水文模式VIC上耦合一个兼顾运行速度和模拟精度的次格网化冰川消融及动态变化方案，并且在冬克玛底冰川进行了验证，并取得了理想的模拟效果；利用改进后的模型对中天山的昆马力克河流域水文水资源对气候变化及冰川退缩的响应机理进行了模拟分析，并对2050s昆马力克河流域的径流进行了预估；基于发展的VIC模型，对发源于青藏高原的五条主要大河的源区水文过程、径流变化、冰川变化等进行了综合模拟和分析，并且对未来100年的径流、冰川变化进行了预估。本项目提出的冰川耦合方法为其他大尺度陆面/大气模式中耦合冰川方案提供重要参考，将为定量评估和预估气候变化下我国西部山区流域水文水资源变化及趋势提供了模式支持；流域尺度的模拟和预估结果也将为这些流域水文水资源管理提供重要参考。