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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >ROLE OF VEGETATION IN SUSTAINING LARGE-SCALE ATMOSPHERIC CIRCULATIONS IN THE TROPICS
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ROLE OF VEGETATION IN SUSTAINING LARGE-SCALE ATMOSPHERIC CIRCULATIONS IN THE TROPICS

机译：植被在维持热带大气压循环中的作用

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The focus of this paper is the role of rain forests in large-scale atmospheric circulations. The significance of this role is investigated by studying the response of the tropical atmosphere to a perturbation in the state of vegetation (deforestation) over three regions: the Amazon, Congo, and Indonesia. A theory is developed to relate tropical deforestation and the resulting changes in the large-scale atmospheric circulation. Field observations and numerical simulations support the argument that tropical deforestation reduces the total net surface radiation, including terrestrial and solar forms. However, the energy balance at the land-atmosphere boundary dictates that for equilibrium conditions, any reduction in net surface radiation has to be balanced by a similar reduction in the total flux of heat, including sensible and latent forms. Since these fluxes supply heat as well as entropy from the forest into the atmospheric boundary layer, a reduction in the total flux of heat reduces the boundary layer entropy. In a moist atmosphere, that satisfies a quasi equilibrium between moist convection and radiative forcing, the equilibrium temperature profile is uniquely related to the boundary layer entropy. Under such conditions, large-scale deforestation reduces boundary layer entropy relative to the surroundings, cools the upper troposphere, and results in subsidence, divergent flow in the boundary layer, and weakening of the large-scale circulation. These changes are simulated using a simple linear model of atmospheric flow. The comparison of the model predictions with observations of atmospheric circulations over the Amazon, Congo, and Indonesia suggests a significant role for vegetation in maintaining large-scale atmospheric circulations in the tropics. [References: 30]
机译：本文的重点是雨林在大规模大气环流中的作用。通过研究热带大气对亚马逊，刚果和印度尼西亚三个地区植被（森林砍伐）状态扰动的响应，研究了这一作用的重要性。发展了一种理论，将热带森林砍伐与大规模大气环流的变化联系起来。实地观察和数值模拟支持以下论点：热带森林砍伐减少了包括地面和太阳形式在内的总净表面辐射。但是，陆地-大气边界处的能量平衡表明，在平衡条件下，净表面辐射的任何减少都必须通过总热通量的类似减少来平衡，包括感性和潜性形式。由于这些通量从森林向大气边界层提供热量以及熵，因此总热量通量的减少会减小边界层的熵。在满足对流和辐射强迫之间的准平衡的潮湿气氛中，平衡温度曲线与边界层熵唯一相关。在这种情况下，大规模的森林砍伐减少了相对于周围环境的边界层熵，冷却了对流层上层，并导致了沉降，边界层中的分流，并削弱了大规模的环流。使用简单的大气流量线性模型可以模拟这些变化。模型预测与亚马逊，刚果和印度尼西亚上空大气环流观测值的比较表明，植被在维持热带地区大规模大气环流中起着重要作用。 [参考：30]

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