高寒山区冰雪升华/蒸发观测实验研究

As an important exchange process of water and heat between the cryosphere and the atmosphere, snow and glacier sublimation/evaporation is principal pathway of moisture content loss of cryosphere. This process is also crucial and difficult part for hydrological processes in the cold regions. However, most researches in regard to snow and glacier sublimation/evaporation mainly conducted in the Antarctic and the Arctic Pole, North America and northern Europe. The related works are scattered in alpine region in China, and lacked of long-term, systematic observation and research. Therefore, this project takes glacier, river ice and snow as objectives. Based the observation equipment in Qilian Alpine Ecology and Hydrology Research Station, Key Laboratory of Inland River Ecohydrology, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, and replenish appropriate relevant experiments. We intend to obtain sublimation/evaporation of three cryospheric elements (glacier, river ice and snow)and its relationship with the proportion of annual precipitation through the observation and simulation. The estimation method of snow and glacier sublimation/evaporation based on the meteorological elements will be discussed. Moreover, impact of sublimation/evaporation process on hydrological processes of alpine mountain watershed will be analyzed. We intend to discuss the role of heat consumption of snow and ice sublimation/evaporation process in the delaying atrophy of cryosphere and reducing heating rate in the alpine regions. We attempt to provide the basic data and parametric methods for water and heat exchange process between the atmosphere and cryosphere and watershed hydrological processes in cold regions in China.

冰雪升华/蒸发是冰冻圈-大气圈水分和热量交换、冰冻圈水分损耗的主要途径之一，也是寒区水文过程中的重要组成部分和难点。但相关研究较少且主要集中在南北极、北美和北欧等地，中国高寒山区相关工作也较为零散，缺乏长期、系统观测与研究。本项目拟依托中科院寒旱所黑河上游站，选取祁连山冰川、河冰和积雪作为研究对象，在现有较多观测设施的基础上，适当补充相关实验，通过观测与模拟，获取实验场冰川、河冰、积雪等3种典型冰冻圈要素的升华/蒸发量，及其与年降水量的比例关系，探讨基于气象要素的冰雪升华/蒸发量估算方法，分析冰雪升华/蒸发过程对高寒山区流域水文过程的影响，探讨冰雪升华/蒸发过程消耗热量在“延缓”冰冻圈萎缩、降低山区升温速率中的作用，为大气-冰冻圈水热交换过程以及寒区流域水文过程研究提供基础数据和可能的参数化方法。

冰雪升华是冰冻圈-大气圈水分和热量交换、冰冻圈水分损耗的主要途径之一，也是寒区水文中的观测与模拟难点；相关研究较少且主要集中在南北极等高纬度地区，中纬度山地特别是冰川的相关研究极少。本项目在祁连山八一冰川顶部（海拔4817m）、葫芦沟沼泽草甸（海拔3711m）和灌丛草甸区（海拔3232m）分别布设了冰川、积雪升华观测场，在黑河上游干流河道布设了河冰升华观测场，人工和自动观测相结合，开展了冰川、积雪和河冰升华观测试验、模拟和对比研究。主要结果：（1）基于多组对比试验，发现直径30cm、高10cm的蒸发盘是冰雪升华观测的最佳设施；（2）提出了一种冰川表面空气动力学粗糙度参数化方案，修正了空气动力块体法，基于该方法计算的升华量与实测数据较为吻合，且精度明显高于涡动相关系统、空气动力学梯度等常用方法；（3）观测与模拟相结合，获取了祁连山冰川、沼泽、草甸长时间序列的（2016/7/1（2017/1/1）-2020/12/31）、精确冰雪升华量：八一冰川表面年均升华量为115.1mm，葫芦沟沼泽草甸和灌丛草甸分别为48.4mm和27.2mm；（4）定量了中纬度山地冰雪升华量在水量和能量平衡中的作用：2017~2020年八一冰川年升华量占降水量的13.7%、升华潜热占净辐射的51.3%；葫芦沟沼泽草甸积雪升华量占同期降雪量的52.7%、升华潜热占同期净辐射的50.3%；（5）黑河上游河冰小时升华量峰值一般出现在15:00-17:00时；年升华量约为180.2mm，升华潜热约占净辐射的36.8%。共发表论文27篇（SCI论文22篇）、授权专利2份、软件1个、成果转化1项；毕业博士4名、硕士1名；在读博士后1名、博士生7名、硕士生1名；全面完成预期目标。项目成果多为初次报道，填补了相关空缺；可为大气-冰冻圈水热交换过程以及寒区流域水文过程研究提供相关重要数据、有效观测手段与估算方法。