Novel infrared differential optical absorption spectroscopy remote sensing system to measure carbon dioxide emission

A CO₂ infrared remote sensing system based on the algorithm of weighting function modified differential optical absorption spectroscopy (WFM-DOAS) is developed for measuring CO₂ emissions from pollution sources. The system is composed of a spectrometer with band from 900 nm to 1700 nm, a telescope with a field of view of 1.12°, a silica optical fiber, an automatic position adjuster, and the data acquisition and processing module. The performance is discussed, including the electronic noise of the charge-coupled device (CCD), the spectral shift, and detection limits. The resolution of the spectrometer is 0.4 nm, the detection limit is 8.5×10²⁰ molecules·cm^-2, and the relative retrieval error is < 1.5%. On May 26, 2018, a field experiment was performed to measure CO₂ emissions from the Feng-tai power plant, and a two-dimensional distribution of CO₂ from the plume was obtained. The retrieved differential slant column densities (dSCDs) of CO₂ are around 2×10²¹ molecules·cm^-2 in the unpolluted areas, 5.5×10²¹ molecules·cm^-2 in the plume locations most strongly affected by local CO₂ emissions, and the fitting error is less than 2×10²⁰ molecules·cm^-2, which proves that the infrared remote sensing system has the characteristics of fast response and high precision, suitable for measuring CO₂ emission from the sources.