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中国沙漠 ›› 2013, Vol. 33 ›› Issue (1): 133-140.DOI: 10.7522/j.issn.1000-694X.2013.00019

• 生物与土壤 • 上一篇    下一篇

夏秋季绿洲荒漠过渡带芨芨草地蒸散及能量平衡特征研究

闫人华1,2, 熊黑钢3,2, 张 芳1,2   

  1. 1.新疆大学 资源与环境科学学院, 新疆 乌鲁木齐 830046;
    2.新疆大学 绿洲生态教育部重点实验室, 新疆 乌鲁木齐 830046;
    3.北京联合大学应用文理学院 城市科学系, 北京 100083
  • 收稿日期:2012-06-01 修回日期:2012-07-30 出版日期:2013-01-20 发布日期:2013-01-20

The Evapotranspiration and Energy Budget of an Achnatherum splendens Grassland in the Oasis-desert Ecotone in Xinjiang, China, during Summer and Autumn

YAN Ren-hua1,2, XIONG Hei-gang3,2, ZHANG Fang1,2   

  1. 1.College of Resource and Enviroment Sciences, Xinjiang University, Urumqi 830046, China;
    2.Key Laboratory of Oasis Ecology, Xinjiang Univesity, Urumqi 830046, China;
    3.Department of Urban Science, College of Applied Arts and Science of Beijing Union University, Beijing 100083, China
  • Received:2012-06-01 Revised:2012-07-30 Online:2013-01-20 Published:2013-01-20

摘要:

以实测气象资料为基础,运用波文比能量平衡法计算绿洲-荒漠过渡带芨芨草的蒸散量,并分析了其蒸散日变化规律及地表能量平衡特征。结果表明:①不同天气条件下的蒸散日变化曲线特征差异显著。晴天因辐射强、蒸散量大,蒸散曲线显示为“高耸”型;由于受云量和降水的影响,阴天曲线呈“平缓”型;雨天曲线则表现为“偏态”型,而平均蒸散曲线变化与晴天较为相似。②随着气候由夏季向秋季转变,早晨蒸散发生和夜间蒸散结束的时间点分别表现出1.73 min·d-1的滞后性和2.02 min·d-1的前移性;同时,蒸散峰值以0.0036 mm·d-1的速度递减。与一些相对叶宽的植被覆盖地相比,芨芨草地蒸散量日际波动幅度较小。③净辐射通量(Rn)、 潜热通量(LE)、感热通量 (H)及 土壤热通量(G)的平均值都表现出较为一致的日循环变化趋势。G/Rn、H/Rn、LE/Rn曲线白天平滑,夜间波动,日出和日落前后波动最为剧烈。潜热占净辐射的58.8%,远大于沙漠、戈壁,而低于绿洲。④晴天波文比(β)日内变化曲线呈明显的下降趋势,平均变化率接近-2%,但日间变化曲线略呈上升趋势,变化率为4.8‰。前者反映了晴天的潜热活动在日内随时间变化而愈来愈强,后者则表明感热活动在夏秋季中随日期的推移而逐渐增强。

关键词: 蒸散, 绿洲-荒漠过渡带, 波文比能量平衡法, 能量平衡, 芨芨草

Abstract:

With the field observed meteorological data and the Bowen-ratio method, the evapotranspiration and energy balance in an Achnatherum splendens grassland in the oasis-desert ecotone in Xinjiang, China, were calculated during the summer and autumn of 2010. The results indicated that: (1) The diurnal evapotranspiration under different weather conditions varied significantly. Due to the strong radiation, the evapotranspirtion curve on the sunny days appeared as "towering" type, while the line in cloudy days manifested as "flatting" type in relation to the cloudiness and precipitation, and that in rainy days appeared as" skewing" type. (2) As the climate changes from summer to autumn, the occurring and ending time of the evapotranspiration within a day had some 1.73 min·d-1 lagging and 2.02 min·d-1 advancing, respectively, the evapotranspiration peak declined at a speed of 0.0036 min·d-1. Compared with the habitats of some plants with relatively wide leaf, the A. splendens grassland showed a smaller diurnal fluctuation of evapotranspiration. (3) The net radiation (Rn), latent heat flux (LE), sensible heat flux (H) and soil heat flux (G) had a similar diurnal changing trend. The curve of G/Rn, H/Rn and LE/Rn in daytime was smooth, however, it fluctuated continually at night, and the most violent fluctuation appeared at the time of sunrise and sunset. Latent heat accounted for 52.7% in net radiatio, which was much larger than that in desert and gobi, but smaller than that in oasis. (4) The intraday curve of β (Bowen ratio) demonstrated a downtrend by about -2%. But its daily variation curve represented slightly an upward trend by about 4.8. The downtrend indicated that the variation of latent heat activity would become stronger with time passing in the sunny days, while the upward trend showed that the intensity of the sensible heat activity would increases gradually with the date advancing from summer to autumn.

Key words: evapotranspiration, oasis-desert ecotone, the Bowen ratio energy balance method, energy balance, Achnatherum splendens

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