激光外差光谱测量技术具有光谱分辨率高、探测灵敏度高、成本低等特点，近年来在温室气体探测、激光大气传输等领域得到了广泛的应用。以3.66 μm 分布反馈式带间级联激光器作为本振光源搭建了一套高分辨率激光外差太阳光谱测量装置，实现了水汽吸收光谱的实时测量，并利用最优估算法对整层大气中的水汽柱浓度进行了反演，得到合肥地区2019年5月22日和23日的水汽柱浓度。反演结果与同步进行观测的傅里叶变换光谱仪EM27/SUN测量结果变化趋势一致，相关性优于0.8，偏差小于15%。研究结果表明，搭建的激光外差光谱测量装置能够实现大气中水汽吸收光谱的实时测量以及水汽柱浓度的精确反演，同时为后续的水汽浓度廓线测量与研究奠定了基础。

Laser heterodyne spectroscopy has been widely used in greenhouse gas detection and laser atmospheric transmission in recent years， because of its high spectral resolution， simple structure and low cost. A laser heterodyne spectrum detection system using 3.66 μm DFB laser as local oscillator source was designed. The real-time and accurate measurements of water vapor absorption spectrum in the whole atmosphere was also realized. Furthermore， the signal-to-noise ratio after 12 averaging is 160.4， and the spectral resolution is 0.009 cm^-1. The average values of water vapor column concentration of Hefei on May 22 and 23 are 1549 ppmv and 1730 ppmv respectively. By comparing and analyzing the measurement results of laser heterodyne spectrometer and Fourier transform spectrometer （EM27/SUN）， the correlation between them is 0.895 and 0.819， and the deviation is 14.2% and 11.2% respectively. With the design and research of the system， the real-time measurements of the solar absorption spectrum of water vapor in the atmosphere and the precise inversions of water vapor column density were realized， which laid a foundation for more accurate detection and concentration inversion of the absorption spectrum of water vapor and its isotope HDO.