红外差分光学吸收光谱技术测量环境大气中的水汽

研究了基于红外差分光学吸收光谱技术的环境大气中的水汽测量方法. 所用实验装置由自制的非分散红外多组分气体分析仪改装而成, 根据HITRAN数据库提供的线强参数,采用Voigt展宽线型和方法,并考虑温度、 气压及仪器函数的影响,计算出了水汽反演波段的有效吸收截面. 将反演的水汽浓度与非分散红外分析仪的测量结果进行了实时对比, 得到了较好的测量一致性,测量相关系数为0.93347. 为今后采用红外DOAS技术测量其他在紫外可见波段无吸收或仅有弱吸收的气体 (如CO₂, CH₄, CO, N₂O等)提供了可借鉴的解决方案.

Measurement of atmospheric water vapor using infrared differential optical absorption spectroscopy

In this paper, we present a method of measuring atmospheric water vapor concentration by using infrared differential optical absorption spectroscopy (DOAS). The experimental setup is converted from a self-made non-dispersive infrared multi-gas analyzer. In the process of DOAS retrieval, the reference absorption cross section is calculated by applying the Voigt broadening method to the absorption lines from HITRAN database. The influences of temperature, pressure and instrument function are also taken into account in the calculation. A validation study of the water vapor measurement is performed by comparing the results measured by a non-dispersive infrared analyzer. The results show good agreement with each other (correlation coefficient = 0.93347). It indicates that the infrared DOAS technique has the potential applications to other gases measurements which have no or weak absorption within the UV region, e.g. CO₂, CH₄, CO, N₂O, etc.