Non-local thermodynamic equilibrium model for H2O 6.3 and 2.7-μm bands in the middle atmosphere
Non-local thermodynamic equilibrium model for H2O 6.3 and 2.7-μm bands in the middle atmosphere
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中层大气中 H2O 6.3 和 2.7-μm 波段的非局部热力学平衡模型
DOI：
10.1029/95jd00383
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发表时间：
1995
影响因子：
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通讯作者：
F. Taylor
中科院分区：
文献类型：
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作者：
M. López‐Puertas;G. Zaragoza;B. Kerridge;F. Taylor
本文提出了一个计算中层大气中H_2O和O_2（1）振动能级布居数的非局域热力学平衡辐射传输模型。在H2O波段的辐射传输处理使用柯蒂斯矩阵方法，并进行了详尽的审查的碰撞过程和它们的速率常数影响这些水平的人口。H2O（010）和O2（1）之间的近共振振动-振动耦合对于在中间层建立它们各自的种群至关重要。H2O（010）的数量在夜间约65 km以上开始显著偏离LTE，该精确高度取决于温度结构。在白天，非LTE开始于大致相同的高度，但相对于夜间显著增强。白天主要的附加激发过程是在中间层上部和热层下部由2.7和6.3 μm处的H2O吸收太阳辐射，以及在中间层下部由O3通过O2（1）的光解离产生的激发。H_2O和O_2（1）振动温度对大气和模式参数的敏感性研究已经完成。对6.9 μm H2O压力调制（PM）和宽带（WB）通道中的ISAMS/UARS测量进行了初步分析。测量结果表明，在白天的辐射在两个通道的增强，相比夜间值，约55公里以上。在WB通道中效果更大。与模型的比较表明，非LTE激发的H2O（010）和（020）的水平负责。
A non-local thermodynamic equilibrium radiative transfer model is presented for the populations of H2O and O2(1) vibrational levels in the middle atmosphere. Radiative transfer in the H2O bands is treated using the Curtis matrix method, and an exhaustive review of the collisional processes and their rate constants affecting the populations of these levels has been carried out. The near resonant vibrational-vibrational coupling between H2O(010) and O2(1) is crucial for establishing their respective populations in the mesosphere. The population of H2O(010) starts departing from LTE significantly above about 65 km at night, this precise altitude being dependent on the temperature structure. At daytime, non-LTE begins at approximately the same height but is significantly enhanced with respect to nighttime. The principal additional daytime excitation processes are absorption of solar radiation by H2O at 2.7 and 6.3 μm in the upper mesosphere and lower thermosphere and excitation from the photodissociation of O3 through O2(1) in the lower mesosphere. A sensitivity study of the H2O and O2(1) vibrational temperatures to the atmospheric and model parameters has been carried out. A preliminary analysis of ISAMS/UARS measurements in the 6.9-μm H2O pressure-modulated (PM) and wideband (WB) channels is presented. The measurements show enhancements in the daytime radiances in both channels, as compared to the nighttime values, above about 55 km. The effect is larger in the WB channel. Comparisons with the model show that non-LTE excitation of the H2O (010) and (020) levels is responsible.
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