Based on the carbon dioxide mass mixing ratio concentration profiles of Hefei Science Island from 2013 to 2016, the distribution characteristics of carbon dioxide in the subtropical monsoon climate and the characteristics of carbon dioxide source and sink in Hefei Science Island were analyzed from the night, season and year respectively. At lower altitudes, CO<sub>2</sub> builds up during nighttime hours as respiration is trapped within the nocturnal boundary layer. Throughout this nighttime the CO<sub>2</sub> concentration at 390m shows that only little variation. After sunrise, convection begins to spread the CO<sub>2</sub> trapped at low levels to higher altitudes. When the measurement height was more than 100m, the obvious seasonal change was shown, with the minimum in summer and the maximum in winter, which the difference in concentration of about 19.32mg/m<sup>3</sup> . The annual distribution of the concentration of carbon dioxide from 2013 to 2016 had no significant difference in the gradient change of the height above 100m, the correlation coefficient was above 0.9, and the CO<sub>2</sub> vertical concentration goes up with a rate of about 4.35mg/m<sup>3</sup> per year. Through data analysis from three different timescales, it could be concluded that the concentration of carbon dioxide near the ground was greatly influenced by the atmospheric environment. The seasonal distribution of carbon dioxide concentration was the result of a combination of atmospheric movement and the activities of plants and animals. In the process of long-term carbon dioxide cycling, there was a current that the near-surface carbon dioxide transported to a higher altitude.
The aerosols near the ground are closely related to human health and climate change, the study on which has important significance. As we all know, the aerosol is inhomogeneous at different altitudes, of which the phase function is also different. In order to simplify the retrieval algorithm, it is usually assumed that the aerosol is uniform at different altitudes, which will bring measurement error. In this work, an experimental approach is demonstrated to measure the scattering phase function of atmospheric aerosol particles at different heights by CCD lidar system, which could solve the problem of the traditional CCD lidar system in assumption of phase function. The phase functions obtained by the new experimental approach are used to retrieve the aerosol extinction coefficient profiles. By comparison of the aerosol extinction coefficient retrieved by Mie-scattering aerosol lidar and CCD lidar at night, the reliability of new experimental approach is verified.