Department of Chemistry and Biochemistry, James Madison University, MSC 4501, Harrisonburg, Virginia 22807, USA.
J Phys Chem A. 2012 Apr 26;116(16):4069-73. doi: 10.1021/jp301194j. Epub 2012 Apr 11.
We present laboratory measurements of H(2)O-broadened (16)O(2) A-band (b(1)Σ(g)(+) ← X(3)Σ(g)(-)(0,0)) absorption spectra acquired with a laser-based photoacoustic spectroscopy method. This absorption band is widely used in a variety of high-precision atmospheric remote sensing applications. We report H(2)O broadening parameters for six of the strongest transitions in this band, and we show that these measured values are nominally 1.5-2 times greater than the corresponding air-broadening parameters. Simulations of atmospheric transmission spectra in the O(2) A-band that incorporate our measured H(2)O broadening parameters indicate that H(2)O present at concentrations typically found in the Earth's atmosphere can influence the column-integrated transmission relative to the dry air case. Further, because of spatial and seasonal variations in humidity, failure to account for the enhanced H(2)O pressure broadening effects can lead to concomitant biases in atmospheric O(2) A-band retrievals of quantities such as surface pressure and path length in greenhouse gas retrievals.
我们展示了使用基于激光的光声光谱法获得的 H(2)O 宽带（16）O(2) A 带（b(1)Σ(g)(+) ← X(3)Σ(g)(-)(0,0))吸收光谱的实验室测量结果。该吸收带广泛应用于各种高精度大气遥感应用中。我们报告了该带中六个最强跃迁的 H(2)O 展宽参数，并且我们表明这些测量值比相应的空气展宽参数大 1.5-2 倍。在大气中包含我们测量的 H(2)O 展宽参数的 O(2) A 带的传输光谱模拟表明，在地球大气中通常存在的浓度的 H(2)O 可以影响相对于干空气情况的柱积分传输。此外，由于湿度的空间和季节性变化，如果不考虑增强的 H(2)O 压力展宽效应，可能会导致大气 O(2) A 带对温室气体反演中的表面压力和路径长度等量的反演出现伴随的偏差。
