土壤冻融是山区（高原）河流径流变化的控制性因素，气候变化下流域水资源预测存在较大不确定性，成为全球变化影响水资源问题的研究热点。本项目依托贡嘎山高山生态站和西藏申扎高寒草原站，通过野外径流场观测和室内土壤冻融模拟试验，重点研究1）高山（高原）环境要素对土壤冻结消融的影响方式，解决不同气候条件下高山（高原）冻土的形成过程和消融特征，确定不同地表覆被下土壤冻融过程的变化规律，建立气温（日气温、累积气温）、地温、地表积雪量、土壤冻结量以及它们与消融速率的关系；2）研究土壤热传导和温度变化模式，揭示高寒环境下的地表能量与水分相互影响关系，探索坡地径流形成条件受到表土层冻融的作用机制，确定地下冻结冰层和土壤水分的转化条件和阈值；3）提出高寒山区产汇流模式及确定相关参数，解决不同尺度地表形态和覆被特性的定量表达方式，研发反映土壤冻融作用的分布式流域水文模型，模拟预测高山（高原）江河源头径流变化趋势。

The soil freezing and thawing effects are the controlling factors of runoff change of mountainous rivers. The prediction to stream flow is of large uncertainty under the influence of climate change, it is the hot-pot in the study on the global change impacting to water resource. Based on the soil freezing-thawing experiments and field runoff observation in Gongga Mountain Ecosystem Station and Shengzha Plateau Prairie Station, our research will focus on: 1) the environment factors and their impacts to alpine soil freezing and thawing, determine the soil-ice formation and melting features, find the quantitative relationship between air-temperature, ground temperature and ice-layer variations; 2)study heat transportation and temperature change in soil profile, explore the influence relationship of energy inputing to groundwater under cold environment. Explore the runoff generation mechanism impacted by the freezing-thawing of surface soil, determine the change conditions and thresholds of soil frost; 3) development the runoff generation model with distributed structure and parameters suitable for cold region, propose theory and methods in the simulation and forecasting of runoff change for riverhead in mountain and plateau.