涡度相关系统是测量水、热和痕量气体通量最直接和最可靠的仪器。基于可调谐半导体激光吸收光谱原理，设计了一种用于测量大气边界层痕量气体通量的新型开路式气体分析仪。通过选择不同的吸收线，可以测量不同痕量气体通量。以4990 cm-1二氧化碳吸收线为例，实验表明，该气体分析仪的采样频率可以达到10 Hz以上，与基于非分散红外原理的涡度相关系统气体分析仪Li-7500对比，测量精度相当，可以达到5×10-7。该分析仪的频率和精度满足构建涡度相关系统的仪器要求，可以用于边界层痕量气体通量的测量。

The fluxes of heat, water and other trace gases are measured directly using eddy covariance method. For eddy covariance measurements, a new calibration-free open-path trace gas analyzer, based on tunable diode laser absorption spectroscopy (TDLAS), is developed and applied for trace gas fluxes in the atmospheric surface layer. By selecting different absorption lines, different trace gases are detected. Carbon diode absorption line (near 4990 cm-1) is taken as an example. The output bandwidth of the new gas analyzer is more than 10 Hz. A comparative experiment is conducted between a reliable commercial analyzer (Li-7500) using non-dispersive infrared (NDIR) gas sensor and our new trace gas analyzer. The collected data demonstrate an excellent qualitative agreement and show that the sensitivity of our gas sensor is about 5×10-7. It is indicated that the fast sampling and high sensitivity meet the requirements of the eddy covariance method. This TDLAS trace gas analyzer is a suitable technique for determining the fluxes of trace gases using eddy covariance method.