增温对金露梅灌丛冻土水热过程影响的试验研究

寒区水文 冻融过程 冻土水热过程 活动层变化 过程观测
刘章文 2016-01 项目
With a warming climate, cold regions ecosystems undergo significant ecological changes such as encroachment of canopy-forming shrubs into tundra communities (termed as shrubification) using repeat photography, long-term ecological monitoring and dendrochronology over past decades. Recent researches have documented that shrub expansion around the cold regions influence the local scale hydrological cycle. shrubification is becoming the important parts, and aroused general interest in cold region hydrological research. However, the effects of this process on freeze-thaw processes and water and heat processes of frozen soil still are unclear. Therefore, we will select the Hulu watershed in Qilian Alpine Ecology and Hydrology Research Station of Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences as experimental area. Based on Open-top chamber stimulated warming method, this program will take Potentilla fruticosa as test object to detect effects of warming and Shrubification on freeze-thaw processes and water and heat processes of frozen soil under shrub cover in Qilian Mountains. The differences of water and heat balance and transfer processes between simulated warming and shrub cover will be analyzed by using experimental data. Then, the CoupModel model will be used to simulate the gradients and transfer characteristic of water and heat in frozen soil under different shrub cover and warming scenarios. Analysis of the impact of shrub cover on pattern and process of water and heat transfer under warming scenarios also will be documented. Finally, we will make a preliminary quantitative assessment for difference of impacts of Shrubification and warming on water and heat transfer processes of frozen soil, and forecast the response of frozen soil water and heat transfer process of frozen soil to the Shrubification process under warming scenarios. The results will provide important parameters and theoretical foundation for large scale hydrological research in cold regions, land surface processes and model research, and global climate change research.
在气候变暖背景下,近几十年来全球寒区出现灌丛化过程,这将改变地表水热状况,影响局地水文循环,是寒区水文研究的热点,但是灌丛化过程对冻土冻融过程及水热传输过程的影响机理、程度还不清楚,相关研究极为薄弱。本项目拟在祁连山中科院寒旱所祁连站葫芦沟试验流域,以不同盖度金露梅灌丛为研究对象,采取开顶式生长室(Open-top chamber,OTC)模拟增温装置,基于野外试验数据,分析灌丛盖度和增温情景下冻土水热平衡及传输过程的差异,以此确定灌丛化过程对冻土冻融过程的影响;结合CoupModel冻土-植被-大气水热耦合模型,探讨升温情景下不同盖度灌丛区冻土分层水热梯度变化及传输特征,分析升温情景下灌丛对冻土水热传输过程的影响,初步定量评估灌丛化与升温引起冻土水热传输过程的时空差异性,预估气温升高后,冻土水热传输对灌丛化过程的响应,为大尺度寒区水文、陆面过程和气候变化相关研究提供相关参数和理论基础。