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应用生态学报 ›› 1999, Vol. 10 ›› Issue (5): 534-538.

• 研究论文 • 上一篇    下一篇

农林复合生态系统与低层大气间的通量研究

王汉杰   

  1. 空军第七研究所, 北京100085
  • 收稿日期:1998-07-20 修回日期:1998-09-16 出版日期:1999-09-25 发布日期:1999-09-25
  • 作者简介:王汉杰,男,48岁,教授,南京林业大学兼职教授,中国科学院沈阳应用生态研究所客座研究员.主要从事森林生态系统的微气象观测和数值模拟研究.编著有《林农复合经营技术》《、林茶复合经营技术》《、生态边界层原理和方法》等书以及有关的研究论文30余篇.E-mail:EERC@orange.cgw.net.cn
  • 基金资助:

    国家自然科学基金资助项目(49575250).

Fluxes between agroforest ecosystem and low level atmosphere

Wang Hanjie   

  1. Meteorological Institute of Air Force China, Beijing 100085
  • Received:1998-07-20 Revised:1998-09-16 Online:1999-09-25 Published:1999-09-25

摘要: 根据近年在黄淮海平原大面积农林复合区的观测资料,采用简单的一维模型,讨论了此类复合系统与低层大气之间的热量、动量和水汽通量,比较了不同的结构林网形成的通量差异。结果表明,由于林冠层的摩擦作用,农林复合生态系统上空风速随高度增大较快,动量输送总是向下的。在层结稳定的夜间,其数值较大,而在湍流比较活跃的正午前后,由于垂直风切变减弱,动量输送也相应减小。夜间农林作物冠层的辐射冷却加强,近地层逆温梯度增大,加之作物冠层内部因辐射冷却而造成水汽凝结,冠层上部水汽大于冠层内部,此时热通量和水汽通量均向下。这一现象在白天日出后开始逆转,日出后,地面升温加快,并逐渐形成超绝热梯度,致使热量通量向上。此时农林作物蒸腾加剧,冠层高度范围内水汽含量增大,造成水汽向上输送。文中还讨论了一维模式的缺点,指出了进一步研究生态系统与大气相互作用的重要性.

关键词: 农林复合生态系统, 湍流通量, 混合长, 街道峡谷, 扩散模拟, 空气质量, 发展趋势

Abstract: Based on the radiosonde data in the agroforest area in Huang Huai Hai plain, a simplified one dimensional model was established to study the momentum, heat and water vapor fluxes above the agroforest ecosystems with three different structures. It was found that because of the frictional effect, the wind velocity above the vegetation canopy increased with height rapidly, which caused an insistent downward momentum flux above the canopy. During the stable clear night, the momentum flux was significant because of the strong wind shear. It becames weak around noon,as the strong turbulence made the vertical wind shear smaller. Both heat and water vapor flux went downward in the night, which caused respectively by the radiation cooling of the vegetation canopy and by the water vapor condensation in the very low level. The heat flux turned upward after sunrise because of the surface heating, which reached to the maximum at noon when the surface super adiabat formed. The water vapor flux turned upward as well, due to the high vapor content in the lowest level caused by the evaportranspiration of the vegetation canopy at day. The author also discussed the flaw of one dimensional model and revealed some important aspects of atmosphere biosphere interaction.

Key words: Agroforest ecosystem, Turbulence flux, Mixing length, street canyons, diffusion simulation, air quality, development trend