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生态学杂志 ›› 2021, Vol. 40 ›› Issue (2): 501-511.

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元江干热河谷林地内外潜在蒸散发量的变化及其驱动因素

王玉洁1,周炳江2,黄郑雯1,孙荣卿1,杨宽1,杨霖1,程希平1*   

  1. 1西南林业大学地理与生态旅游学院, 昆明 650224;2西南林业大学园林园艺学院, 昆明 650224)
  • 出版日期:2021-02-10 发布日期:2021-07-09

The variation and driving factors of potential evapotranspiration of the forest interior and open land in Yuanjiang dry-hot valley, China.

WANG Yu-jie1, ZHOU Bing-jiang2, HUANG Zheng-wen1, SUN Rong-qing1, YANG Kuan1, YANG Lin1, CHENG Xi-ping1*   

  1. (1School ofGeographyand Ecotourism, Southwest Forestry University, Kunming 650224, China; 2School of Landscape Architecture and Horticulture Science, Southwest Forestry University, Kunming 650224, China).
  • Online:2021-02-10 Published:2021-07-09

摘要: 蒸散发对把握气候变化、理解区域生态保护具有重要意义。本文利用主成分分析及皮尔逊双侧相关检验的方法研究元江干热河谷林地内外潜在蒸散发量(PET)的变化及其驱动因素,并根据分析结果对林地内外蒸散发的发生过程进行解读。通过对2015—2018年日PET的研究发现:林内PET比林外低0.86 mm·d-1;林地内外PET呈周期式减小,林外的减小趋势更大。2015—2018年及对应年份旱雨季的林地内外干旱指数显示,元江的干旱程度在研究时间段内有所缓解,林内干旱指数较林外更低。林内日PET的驱动因素依次是气温(Ta)、地面净辐射(Rn)、5 cm土壤热通量;林外日PET的驱动因素依次是Ta、5 cm土壤温度、Rn。林内蒸散发的发生层按蒸散发的剧烈程度所划分的层次性较清晰,剧烈层位于稀树灌丛林型的中上层,蒸散发的剧烈程度由中上层向下依次减弱;林外蒸散发的发生层层次性较混合,剧烈层位于近地面空气与土壤交汇层。

关键词: 稀树灌丛生态系统, 林地内外, 潜在蒸散发

Abstract: Evapotranspiration is of great significance for understanding climate change and regional ecological protection. We analyzed the variation and driving factors of potential evapotranspiration (PET) of Yuanjiang savanna ecosystem research station in China through principal component analysis and Pearson’s twosided correlation test. The process of evapotranspiration was interpreted according to the analysis results on forest interior and open land. Results from the analyses on daily PET data from 2015 to 2018 showed that thePET in forest interior was 0.86 mm·d-1 lower than that in open land. The PET in forest interior and open land showed a periodic decrease, with a greater decrease trend in the open land. The drought index of the forest interior and open land in the dry and rainy seasons during 2015-2018 and corresponding years was calculated. Results showed that the drought degree of Yuanjiang savanna ecosystem was alleviated in the study period, with the drought index in forest interior being lower than that in open land. The driving factors of PET in forest interior were air temperature (Ta), surface net radiation (Rn), and soil heat flux at 5 cm below the surface. The driving factors of PET in open land were Ta, soil temperature at 5 cm below the surface, and Rn. The layers of evapotranspiration in forest interior could be clearly divided according to its intensity. The intense layer lay in the middle-upper layer of the shrub forest type and the intensity of evapotranspiration decreased from the middle-upper layer to the lower layer. The layers of evapotranspiration in the open land were relatively mixed, and the layer with the highest intensity of evapotranspiration located in the interface of air and soil.

Key words: savanna ecosystem, forest interior and open land, potential evapotranspiration.