Profiling Atmospheric SO₂?NO₂ And CO₂ By Lidar

Carbon dioxide?CO₂?is the most important greenhouse gas in the atmosphere.CO₂ is very important for the energy balance of the Earth system and the interaction between the biosphere and the atmosphere.Long-term changes in CO₂ concentration will cause many climatic and environmental effects.Sulfur dioxide?SO₂?and nitrogen dioxide?NO₂?in the atmosphere are trace contaminated gases which have important ef-fects on human health.The lidar observation of the SO₂ and NO₂ in the boundary layer was carried out.The temporal and spatial distribution characteristics of SO₂ and NO₂ were obtained by analyzing the data.CO₂ in the boundary layer was observed by lidar.The mechanism of CO₂ exchange and the trend of CO₂ concentration in the mixed atmosphere and biosphere were revealed by analyzing the data.The research work of this paper is divided into three parts.The first part is a summary.The sources and cycles of atmospheric SO₂,NO₂ and CO₂ are summarized.The optical monitoring technology of these gases is introduced in detail.Some important concepts of laser-atmosphere interaction,lidar equation,dif-ferential absorption lidar and Raman lidar are described.The research progress of lidar detection of SO₂,NO₂ and CO₂ in the atmosphere is reviewed.The second part is the research of lidar detection of SO₂ and NO₂ in the atmo-sphere.?1?Based on SO₂/NO₂ differential absorption lidar,the effects of atmospheric molecules and aerosols are analyzed,and the inversion algorithm models of SO₂ and NO₂ are established.?2?Based on the observation data of SO₂/NO₂ differential ab-sorption lidar at Huainan Research Institute,Institute of Atmospheric Physics,Chinese Academy of Sciences,the spatial distribution trend,source correlation and transport process of SO₂ and NO₂ at 0.2 km?3.0 km were quantitatively analyzed.During the period from June 2016 to September 2017,the correlation coefficient of the temporal variation of SO₂ and NO₂ concentration is greater than 0.6,and the correlation with spatial distance is greater than 0.7,which indicates that there is a positive correlation between the temporal and spatial distribution of SO₂ and NO₂ sources.The concen-tration distribution of SO₂ and NO₂ is closely related to the distribution of pollution sources and meteorological conditions.Inverse temperature has a strong inhibition ef-fect on the diffusion of SO₂ and NO₂ in the vertical direction.The concentration of SO₂ decreases most rapidly near the detection height of 1.3 km,and the mass con-centration of NO₂ decreases most rapidly near the detection height of 0.7 km.The concentration of SO₂ and NO₂ in the atmosphere is high in winter and at the peak of commuting.?3?Using SO₂/NO₂ differential absorption lidar observation data in Yangbajing,Tibet,the concentration distribution of SO₂ and NO₂ was analyzed.Distribution characteristics of SO₂ and NO₂ in plateau area and their temporal and spatial variations were preliminarily obtained.Based on the observation data from Oc-tober 2017 to June 2018,the atmospheric transport effect in Yangbajing area of Tibet is strong,which is conducive to the diffusion of polluted gases.The diffusion height of SO₂ and NO₂ in the vertical detection path is lower than that in Huainan area.The third part is the lidar detection of CO₂ in the atmosphere.?1?According to the detection principle of ARL-1 Raman lidar,the CO₂ inversion algorithm model is established.?2?Based on the CO₂ volume mixing ratio concentration profiles of Hefei Science Island from 2013 to 2017,the distribution characteristics of CO₂ in the subtrop-ical monsoon climate and the characteristics of CO₂ source and sink in Hefei science island were analyzed from the night,season and year respectively.The concentration of CO₂ in the atmosphere decreased with the increase of altitude,the CO₂ concentration of 390 m was about 95%that of 15m.The concentration of CO₂ gradually increased at night?about 5%?,while there was a tendency to decrease at drawn.When the measure-ment height was more than 100 m,the obvious seasonal change was shown,with the minimum in summer and the maximum in winter,which the difference in concentration of about 10 ×10^-6.With a yearly growth rate of about 2.2 ×10^-6,the annual distribu-tion of the concentration of CO₂ from 2013 to 2016 had no significant difference in the gradient change of the height above 100 m,the correlation coefficient was above 0.9,and the volume mixing ratio concentration increased.?3?Through data analysis from three different timescales,it could be concluded that the concentration of CO₂ near the ground was greatly influenced by the atmospheric environment.The seasonal distribu-tion of CO₂ concentration was the result of a combination of atmospheric movement and the activities of plants and animals.In the process of long-term CO₂ cycling,there was a current that the near-surface CO₂ transported to a higher altitude.