青藏高原不同区域蒸散发变化特征及影响因子分析

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  • 1. 兰州大学大气科学学院,甘肃 兰州 730000
    2. 青藏高原环境变化与地表过程重点实验室,中国科学院青藏高原研究所,北京 100029
    3. 中国科学院大学,北京 100101
    4. 中国科学院中国-巴基斯坦地球科学研究中心,四川 成都 610299

网络出版日期: 2025-05-20

基金资助

国家自然科学基金项目(42230610U2442213

Analysis of Evapotranspiration Variation Characteristics and Influencing Factors in Different Regions of the Tibetan Plateau

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  • 1. College of Atmospheric Sciences,Lanzhou University,Lanzhou730000,Gansu,China;
    2. Key Laboratory of Plateau Environmental Change and Surface Processes,Institute of Tibetan Plateau Research,
    Chinese Academy,Beijing100029,China;
    3. University of Chinese Academy of Sciences,Beijing100101,China;
    4. China-Pakistan Earth Science Research Center,Chinese Academy of Sciences,Chengdu610299,Sichuan,China

Online published: 2025-05-20

摘要

为探究青藏高原不同气候区内蒸散发的长期变化特征及其主要影响因子,加深对高原地区地气相互作用及生态水文过程的理解,本研究选取了慕士塔格站、那曲站、珠峰站和藏东南站作为典型观测点,并基于站点长期观测数据及卫星遥感资料,计算各站点不同时间尺度下的实际蒸散发量,同时分析其与环境因子的相关性,并利用路径分析方法量化季风期内各环境因子对日蒸散发量的影响。结果表明:(1)在年蒸散发量方面,那曲站最高,多年平均值达 592. 17 mm,藏东南站略低,为 521. 34 mm;慕士塔格站次之,为 422. 84 mm;珠峰站最低,仅 206. 33 mm,远低于其他站点。(2)对于年蒸散发与降水的比值而言,慕士塔格站由于降水较少,其比值最大,为 3. 34;其次是那曲站,为 1. 11;珠峰站的比值接为 0. 96,局地水分收支接近平衡,蒸散发水分主要来源于降水;而藏东南站的比值最低,仅为 0. 68,表明该站点下垫面较强的水土保持能力,较多的降水盈余有利于水资源的积累和植被生长。(3)年际变化趋势分析显示,慕士塔格站、那曲站及藏东南站的年蒸散发量均呈上升趋势,其中慕士塔格站的增加主要归因于净辐射的持续增强;那曲站的蒸散发增长与土壤含水量的增加密切相关;藏东南站的上升趋势则主要受气温升高的驱动。相比之下,珠峰站的蒸散发量呈下降趋势,主要受季风期降水减少的影响。(4)各站点蒸散发受不同环境因子的控制。慕士塔格站的蒸散发主要受净辐射和土壤含水量控制,水分来源于冰川融水补给;珠峰站因水汽输送有限,蒸散发主要受降水控制;那曲站的蒸散发受净辐射和土壤含水量共同调控,受能量因子的限制作用更强;藏东南站降水充沛,蒸散发受水分限制较弱,主要受净辐射和气温影响。(5)植被覆盖对蒸散发的调控作用在那曲站和藏东南站较明显,而慕士塔格站和珠峰站由于植被稀疏,相关性较弱。(6)在非季风期,各站点水汽供应显著减少,除藏东南站外,其余站点土壤冻结,土壤含水量处于全年最低水平,蒸散发过程主要受净辐射控制,而藏东南站由于水汽输送减少,蒸散发更多依赖降水供给。

本文引用格式

陈霆炜, 马耀明, 谢志鹏, 王宾宾, 左洪超 . 青藏高原不同区域蒸散发变化特征及影响因子分析[J]. 高原气象, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00048

Abstract

To investigate the long-term variation characteristics of actual evapotranspirationETain different climatic regions of the Tibetan Plateau and its main influencing factorsas well as to enhance the understanding of land-atmosphere interactions and eco-hydrological processes in the plateau regionthis study selected MA‐ WORSBJQOMSand SETORS as representative observational sites. Based on long-term site observations and satellite remote sensing datathe ETa at different temporal scales was calculated for each siteand its correlation with meteorological factors was analyzed. Furthermorea path analysis method was employed to quantify the impact of environmental factors on daily ETa during the monsoon season. The results showed that:(1In terms of annual ET aBJ exhibited the highest valuewith a multi-year average of 592. 17 mmfollowed by SETORS at 521. 34 mm. MAWORS ranked thirdwith an annual ETa of 422. 84 mmwhile QOMS had the lowest ET a of only 206. 33 mmsignificantly lower than the other sites.2Regarding the ratio of annual ETa to precipitationMAWORS had the highest value at 3. 34 due to its low precipitation. BJ followed with a ratio of 1. 11while QOMS had a ratio of 0. 96indicating a near balance in local water budgetwith precipitation being the primary water source for ETa. SETORS exhibited the lowest ratio of 0. 68suggesting a strong water retention capacity of the underlying surfacewith a surplus of precipitation conducive to water resource accumulation and vegetation growth.3The interannual variation trends showed that annual ETa at MAWORSBJand SETORS displayed an increasing trend. The increase at MAWORS was mainly attributed to the continuous enhancement of net radiationwhile the rise in BJ was closely related to an increase in soil moisture content. The upward trend at SETORS was primarily driven by rising temperatures. In contrastQOMS showed a decreasing trend in ETa, mainly due to a reduction in precipitation during the monsoon season.4ETa at different sites was controlled by various environmental factors. At MAWORSETa was primarily regulated by net radiation and soil moisture con‐ tentwith glacier meltwater serving as a significant water source. At QOMSwhere the terrain acts as a barrier to water vapor transportETa was predominantly controlled by precipitationshowing a clear water-limitation effect. At BJETa was jointly regulated by net radiation and soil moisturewith a stronger energy-limitation effect. At SETORSabundant precipitation resulted in weak water limitations on ETamaking it mainly influenced by net radiation and temperature.5The regulatory effect of vegetation cover on ETa was more evident at BJ and SETORSwhereas at MAWORS and QOMSthe correlation was weaker due to sparse vegetation.6During the non-monsoon periodwater vapor supply decreased significantly at all sites. Except for SETORSsoil at the other sites remained frozenwith soil moisture content reaching its lowest level of the year. Consequentlythe ET a process was mainly controlled by net radiation. At SETORSwhere water vapor transport was reducedETa relied more on precipitation supply.
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