疏勒河上游多年冻土区不同下垫面蒸散发估算方法研究

遥感反演模型/算法为区域蒸散发估算提供了重要手段，但由于冻土区复杂的固-液-气三相转换，使得遥感反演模型/算法在多年冻土区的蒸散发估算存在很大的误差。本项目拟选取已有多年观测试验基础的寒区-疏勒河上游作为研究区，以SEBAL模型和MOD16算法为基础，综合考虑多年冻土区冻融水热过程的影响，对土壤热通量算法进行改进，并利用空气动力学方法估算区域积雪表面升华，以此提高遥感模型/算法在寒区多年冻土区不同下垫面的估算精度；确定影响多年冻土区蒸散发变化的关键参数，并分析研究区不同下垫面的蒸散发时空分布特征；进一步获取疏勒河上游多年冻土区长时间序列的区域蒸散发，结合加密降水观测数据，定量分析不同下垫面的水量平衡特征。研究结果有助于厘清疏勒河上游多年冻土区的水资源空间分布，为进一步揭示区域水循环对气候变化的响应及冻土区生态水文过程提供参考。

Remote Sensing model and algorithm provide fundamental supports for the estimation of regional evapotranspiration (ET). However, since the complex transitions among solid, liquid and gas in permafrost regions, large errors exist in the estimation of ET for some remote sensing models and algorithms. This research intends to select the permafrost regions in the upper reach of the Shule River Basin (SRB) as study area. Based on Surface Energy Balance Algorithm for Land model (SEBAL) and MOD16 algorithm, the soil heat flux algorithm can be improved by synthetically considering the effect of freezing and thawing process of permafrost, with aerodynamics method for the estimation of regional sublimation at the snow surface; and the evaluation accuracy of remote sensing model and algorithm can be effectively increased for the different underlying surfaces in permafrost region. The key parameters which impact the evolution of permafrost can be determined, and spatiotemporal evapotranspiration distributions of different underlying surfaces are analyzed. The long term series of regional evapotranspiration can be further required in the permafrost region of the upper reach of SRB. Quantified characteristics of water balance in the different underlying surfaces are quantitative analyzed based on intensive precipitation observation data. The results are helpful to clarify the spatial distribution of water resource in permafrost regions of the upper of SRB, and provide guidance for further revealing the response of regional water cycle to climate change and eco-hydrological processes in permafrost areas.