长江源区典型高寒沼泽草甸地表能量平衡特征及其影响因素  

Characteristics of surface energy budget of typical alpine swamp meadows in the source region of Yangtze River and its influencing factors

作　　者：郭浩楠 汪少勇 叶虎林 何晓波 丁永建 洪晓峰[4] 付辉[5] GUO Haonan;WANG Shaoyong;YE Hulin;HE Xiaobo;DING Yongjian;HONG Xiaofeng;FU Hui(State Key Laboratory of Cryospheric Science,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China;Qinghai Golmud Hydrology and Water resources Survey and Prediction Sub-center,Golmud 816000,Qinghai,China;Changjiang River Scientific Research Institute of Changjiang Water Resources Commission,Wuhan 430010,China;China Institute of Water Resources and Hydropower Research,Beijing 100049,China)

机构地区：[1]中国科学院西北生态环境资源研究院,冰冻圈科学国家重点实验室唐古拉山冰冻圈水文与生态野外科学实验站,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]青海省格尔木水文水资源测报分中心,青海格尔木816000 [4]长江水利委员会长江科学院,湖北武汉430010 [5]中国水利水电科学研究院,北京100049

出　　处：《冰川冻土》2023年第5期1501-1515,共15页Journal of Glaciology and Geocryology

基　　金：中国科学院与青海省人民政府三江源国家公园联合研究项目(LHZX-2020-11-1);西藏自治区科技计划重大科技专项(XZ202101ZD0009G);中国水科院科研专项(HY110145B0012021);中央级科研院所基本科研业务费项目(CKSF2021485);冰冻圈科学国家重点实验室项目(SKLCS-ZZ-2022)资助。

摘　　要：广泛分布的草地是长江源区水源涵养的重要生态系统之一。在气候变暖的背景下,高寒草地生态系统的空间分布格局发生了深刻的变化,高寒沼泽草甸显著退化,正面临着逐步消失的风险,并且目前对于高寒沼泽草甸能量平衡过程及其演化过程的观测不足,难以支撑进一步的机理研究。通过开展高寒沼泽草甸地区的能量平衡观测研究,深入理解高寒沼泽草甸能量平衡和水量平衡过程特征并分析影响因素和驱动力,能够为沼泽草甸的保护和修复提供数据基础和理论支撑。本研究基于长江源区布曲冬克玛底河流域典型高寒沼泽草甸2020年涡动相关设备测量所获取的连续、高质量的能量平衡观测数据,探究了当地能量平衡特征及其影响因素。研究发现:冬克玛底流域的气候特征呈现夏秋季温润、冬春季冷干的季节特征,下垫面土壤存在长时间的饱和状态以及明显的冻融循环过程。独特的气候及下垫面条件使高寒沼泽草甸具有独特的能量平衡特征,表现在净辐射主要被感热和潜热所消耗,分别达到全年的46.1%和55.6%,仅有1.7%转化为土壤热通量。净辐射在夏秋季主要转化为潜热,冬春季主要转化为感热,潜热通量相较于其他高寒草甸类型占比更大且更集中在夏秋季,高寒沼泽草甸年总潜热占比可达有效辐射的55%,夏秋季潜热通量可达同时期有效辐射的73%。在植被生长季,高寒沼泽草甸提高了饱和水汽压差对潜热通量带来的影响,削弱了净辐射带来的影响并使得土壤热通量表现为:生长前期>生长中期>生长后期。高寒沼泽草甸地区存在的土壤冻融过程也改变了地表能量平衡特征,主要表现在湍流通量除受净辐射控制外,在消融时期土壤温度及含水量导致了湍流通量潜热通量为主、冻结时期以感热通量为主的变化特征。The widely distributed grassland is one of the important ecosystems for water conservation in the Source Region of the Yangtze River.Under climate warming,the spatial distribution pattern of the alpine grass⁃land ecosystem changed profoundly,and the alpine swamp meadow degraded significantly.The alpine swamp meadow in the Source Region of the Yangtze River is facing the risk of gradual disappearance.In addition,the current observations on the surface energy budget and its evolution process of alpine swamp meadow were insuf⁃ficient to support further mechanism research.Through the observed energy budget in the alpine swamp meadow area,the characteristics of the energy budget and water balance process of the alpine swamp meadow would be deeply understood,and the analysis of the influencing factors and driving forces can provide data basis and theo⁃retical support for the protection and restoration of the alpine swamp meadow.This study is based on the continu⁃ous and high-quality observation data of energy budget obtained by eddy covariance system measurement in 2020 for typical alpine swamp meadow in Dongkemadi Watershed in the Source Region of the Yangtze River,and dis⁃cusses the factors of energy budget.The results are as follows:the climate of Dongkemadi Basin(DKB)was warm in summer and autumn,cold and dry in winter and spring.The underlying soil is saturated for a long time and has an obvious freezing-thawing cycle.The net radiation was mainly consumed by sensible heat and latent heat,which reached 46.1%and 55.6%respectively,and only 1.7%was converted into soil heat flux.The unique climate and alpine swamp meadow underlying surface conditions that have unique characteristics of ener⁃gy budget performance in alpine meadow of latent heat flux(LE)compared with other alpine meadow of than larger and more concentrated in the summer fall,alpine swamp meadow in total account for 55%of the ratio can reach effective radiation,latent heat flux(LE)can be up to the same period 73%of effective radiation.Volumet�

关 键 词：长江源区 沼泽草甸 多年冻土 能量平衡 

分 类 号：P642.14[天文地球—工程地质学] P422.4[天文地球—地质矿产勘探]