Vertical Distributions of CO2 Volume Ratio and Aerosol Extinction Coefficients in Low-Altitude Utilizing Mie–Raman Lidar at Nanyang City, China

Abstract

The first experiment was conducted to monitor vertical distributions of carbon dioxide (CO2) and aerosols in the low troposphere (below 1 km) using a self-developed mobile, integrated, and 3-D scannable ground-based Mie-Raman lidar in Nanyang, Henan Province, China. The mean volume ratio of CO2 at low altitude (below 200 m) ranged from 418 to 419 ppm, with an average fluctuation of 7–9 ppm, and the mean volume ratio of CO2 was primarily distributed between 406 and 420 ppm during experimental periods. The vertical distribution of CO2 volume ratios exhibited a gradually decrease trends with increasing altitude integrally indicating that observation site belonged to carbon source regions. The quality of the CO2 echo signal was improved with decreasing daylight intensity. Specifically, the stratification of CO2 with time is gradually evident in the observations. The high aerosol extinction coefficients in Nanyang were mainly concentrated below an altitude of approximately 300 m, indicating that pollution near the ground was heavy. The vertical distribution of aerosol extinction coefficients was characterized by the phenomenon that altitudes of high value declined at night due to atmospheric dry deposition. This study demonstrated that our Mie-Raman scattering lidar can successfully obtain the vertical distribution of CO2 volume ratio and aerosol extinction coefficient, which can provide new datasets and technological support for local environmental department and “carbon neutrality” scientific research.