A study of infrared diabatic forcing of ice clouds in the tropical atmosphere
A study of infrared diabatic forcing of ice clouds in the tropical atmosphere
复制标题
热带大气中冰云的红外非绝热强迫研究
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
R. Rizzi
中科院分区：
文献类型：
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作者：
T. Maestri;R. Rizzi
[1]研究了热带标准条件下大气和冰云层内部的非绝热交换。从云层经历净发射（大致为远红外）的光谱区域到经历净吸收（窗口）的光谱区域的交叉并不显著依赖于冰的数量，但似乎与云的高度和大气温度结构密切相关。对于固定的大气，云的内部辐射加热和冷却结构高度依赖于云的透过率。在卷云底部的冰晶所吸收的能量与占据同一层的空气分子所吸收的能量不同，散射的影响被量化并与粒子的发射进行比较。对球形和六边形柱状冰粒子进行了模拟。由于我们对冰云的一些主要特性（如冰量和有效半径）的认识不足而引起的不确定性，补偿效应在积分量上产生了很小的差异，这些不确定性与补偿效应相比显得相当不重要。由于水蒸汽浓度的变化，水层吸收通量的变化幅度更大。
[1] The diabatic exchange occurring in the atmosphere and within ice cloud layers in tropical standard conditions is investigated. The crossover from the spectral region in which the cloud's layer experiences a net emission (roughly the far infrared) to the region in which it experiences net absorption (window) does not significantly depend on the ice amount, but appears strictly connected with cloud's height and atmospheric temperature structure. For a fixed atmosphere, the cloud's internal structure of radiative heating and cooling is highly dependent on cloud trasmissivity. The energy absorbed by ice crystals at the base of a cirrus is different from that absorbed by the air molecules occupying the same layer and the effects of scattering are quantified and compared to particle's emission. Simulations have been done in case of spherical and hexagonal column-shaped ice particles. Small differences are obtained in the integrated quantities due to compensating effects which appear fairly unimportant when compared to uncertainties caused by our inadequate knowledge of some of the main properties of ice clouds, such as ice amount and effective radius. Of larger magnitude are variations in layer's absorbed flux due to changes in the water vapor concentration.