Remote optical measurement techniques are valuable tools for the quantification of combustion-generated, climate-forcing emissions. Leveraging radiometric observations along a detector's line-of-sight, these techniques resolve column density information from which pollutant loading and emission rates can be deduced for an in situ atmospheric plume of a targeted source. One commonly neglected source of uncertainty in such measurements is beam steering – the deflection of light as it traverses the plume due to composition- and temperature-driven gradients in the real refractive index field of the plume. In this work, three correction parameters were derived from the radiative transfer equation to enable consideration of beam steering effects on these measurement techniques. A Monte Carlo procedure was performed to derive realistic optical axes through plumes of large-eddy-simulated gas flares, considered to be an extreme case of beam steering due to elevated temperature and composition gradients near the flame. Deflections of light due to beam steering were quantified at wavelengths in the visible spectrum and within three diagnostic-relevant infrared absorption bands for methane and carbon dioxide. A conservative, empirical model for the degree of beam steering was derived. Moreover, from these data, correction parameters required to account for the impact of beam steering on perceived incident intensity, optical depth, and source intensity were found to be negligible at all studied wavelengths relative to typical instrument noise. Thus, this work demonstrates that even for the extreme case of a turbulent heated flare plume, beam steering has negligible impact on the ability to quantify pollutant loading and emissions.

远程光学测量技术是量化燃烧产生的强迫气候排放的有价值的工具。利用沿探测器视线进行的辐射观测，这些技术可解析柱密度信息，从中可以推断出目标源的原地大气羽流中的污染物负荷和排放率。在这种测量中，通常被忽略的不确定性来源之一是光束转向-由于光线在烟羽的实际折射率场中受成分和温度驱动的梯度的影响，光线穿过烟羽时会发生偏转。在这项工作中，从辐射传递方程中导出了三个校正参数，以考虑光束转向对这些测量技术的影响。进行了蒙特卡罗程序，以通过大涡流模拟的气体耀斑的羽流得出真实的光轴，由于温度升高和靠近火焰的成分梯度，这被认为是光束转向的极端情况。由光束控制引起的光偏转在可见光谱中的波长处以及在甲烷和二氧化碳的三个与诊断相关的红外吸收带内进行量化。推导了光束转向程度的保守的经验模型。此外，从这些数据中发现，在所有研究的波长下，相对于典型的仪器噪声，考虑到光束转向对感知的入射强度，光学深度和光源强度的影响所需的校正参数可忽略不计。从而，