| 青藏高原两类下垫面地表能量分配对气候要素的响应研究 |
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| 引用本文： | 葛骏,余晔,解晋,昝蓓蕾.青藏高原两类下垫面地表能量分配对气候要素的响应研究[J].大气科学,2017,41(5):918-932. |
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| 作者姓名： | 葛骏 余晔 解晋 昝蓓蕾 |
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| 作者单位： | 1.中国科学院西北生态环境资源研究院寒旱区陆面过程与气候变化重点实验室, 兰州 730000 |
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| 基金项目： | 国家重大科学研究计划2013CB956004 |
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| 摘 要： | 利用青藏高原北麓河观测站（退化高寒草甸）和玛曲观测站（高寒草原）2014年地面观测资料，通过组合分类法，对比分析了两类下垫面生长季土壤含水量、水汽压差和净辐射对地表能量分配的直接影响和间接影响，并且利用路径分析法研究了影响地表能量分配的关键气候因子。结果表明:北麓河站和玛曲站潜热占比（潜热通量与地表可利用能量的比值）对土壤含水量的响应分别处于土壤水分抑制阶段和能量抑制阶段。其中，北麓河站潜热占比在水汽压差较大时随土壤含水量增长较快，受净辐射的影响较小；而玛曲站潜热占比随土壤含水量的变化趋势受水汽压差和净辐射的影响均较小。北麓河站潜热占比随水汽压差的增大先减小后趋于不变，并且潜热占比对水汽压差的敏感性随土壤含水量的增大而减小；而玛曲站潜热占比随水汽压差的增大先增大后趋于不变，几乎不受土壤含水量和净辐射的影响。北麓河站和玛曲站潜热占比均随净辐射的增大趋于稳定，其稳定值分别与土壤含水量和水汽压差有关。路径分析结果显示，降水是影响北麓河站潜热占比的主要气候因子，而气温是影响玛曲站潜热占比的主要气候因子。
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| 关 键 词： | 潜热占比 植被 气候因子 青藏高原 |
| 收稿时间： | 2016/7/19 0:00:00 |
A Study on Responses of Surface Energy Partitioning to Climatic Factors on Two Types of Underlying Surface over Qinghai-Xizang Plateau |
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| GE Jun,YU Ye,XIE Jin and ZAN Beilei.A Study on Responses of Surface Energy Partitioning to Climatic Factors on Two Types of Underlying Surface over Qinghai-Xizang Plateau[J].Chinese Journal of Atmospheric Sciences,2017,41(5):918-932. |
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| Authors: | GE Jun YU Ye XIE Jin and ZAN Beilei |
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| Institution: | 1.Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 7300002.Pingliang Land Surface Process & Severe Weather Research Station, Chinese Academy of Sciences, Pingliang, Gansu Province 7440153.University of Chinese Academy of Sciences, Beijing 1000494.School of Atmospheric Sciences, Nanjing University, Nanjing 210023 |
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| Abstract: | Based on surface observational data obtained at Beiluhe site (degraded alpine meadow) and Maqu site (alpine grassland) over Qinghai-Xizang Plateau in 2014, a combinatorial stratification method was used to compare and analyze direct and indirect effects of soil water content, vapor pressure deficit and net radiation on surface energy partitioning. A path analysis method was used to study the key climatic factors that influence the surface energy partitioning on two types of underlying surface. The results show that the response of evaporative fraction(the ratio of latent heat flux to the available energy of the land surface) to soil water content stays in the soil moisture-limited regime at Beiluhe site and energy-limited regime at Maqu site. Evaporative fraction grows fast with increases in soil water content at high levels of vapor pressure deficit and net radiation has little impact on the variation of evaporative fraction at Beiluhe site. The variation of evaporative fraction with changes in soil water content is not influenced by vapor pressure deficit and net radiation at Maqu site. Evaporative fraction first decreases and then tends to be stable as vapor pressure deficit increases, and the sensitivity of evaporative fraction to vapor pressure deficit decreases when soil water content becomes larger while it is independent of net radiation at Beiluhe site. Evaporative fraction increases slightly as vapor pressure deficit increases at first, and then becomes stable and is no longer influenced by soil water content and net radiation at Maqu site. At both sites, evaporative fraction tends to become stable as net radiation increases and the stable value is determined by soil water content at Beiluhe site and vapor pressure deficit at Maqu site. Results from path analysis indicate that precipitation is the dominant factor that controls evaporative fraction at Beiluhe site and air temperature is the dominant factor for evaporative fraction at Maqu site. |
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| Keywords: | Evaporative fraction Vegetation Climatic factor Qinghai-Xizang Plateau |
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