Greenhouse gases have a significant impact on general global climate change. A self-calibrated multiharmonic measurement system based on tunable diode laser absorption spectroscopy (TDLAS) with wavelength modulation spectroscopy, using the vertical-cavity surface-emitting laser, is developed and applied to measure the CO2 and H2O concentrations in the urban areas. The precision of the developed system is evaluated using the Allan variance method, and it is found that the multiharmonic can enhance the precision of the system and the first-to-third harmonics are sufficient to achieve the lowest Allan deviation. To validate its accuracy, comparison experiments with the commercial nondispersive infrared (NDIR) instrument (Li-Cor 840A) are performed and the results demonstrate the high accuracy of the TDLAS system and its consistency with the NDIR instrument. Measurements were carried out in autumn and winter of 2017 in the city center of Munich. The results indicate that the in situ measurement of the CO2 concentration in the downtown area correlates with both natural and anthropogenic activities. Due to its high precision and accuracy, the self-calibrated multiharmonic measurement system has a great potential to further study the emission and distribution of CO2 in the urban areas.
1.Tech Univ Munich, Dept Elect & Comp Engn, D-80333 Munich, Germany 2.Zhejiang Univ, State Key Lab Clean Energy Utilizat, Hangzhou 310027, Zhejiang, Peoples R China 3.Shandong Sci Acad, Laser Res Inst, Shandong Key Lab Opt Fiber Sensing Technol, Jinan 250014, Shandong, Peoples R China
Recommended Citation:
Lan, Lijuan,Chen, Jia,Wu, Yingchun,et al. Self-Calibrated Multiharmonic CO2 Sensor Using VCSEL for Urban In Situ Measurement[J]. IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT,2019-01-01,68(4):1140-1147