Correction Algorithm of Atmospheric NO2 Concentration Caused by Heavy Aerosol Load in Differential Absorption Lidar

Differential absorption lidar (DIAL) is an effective instrument for detecting nitrogen dioxide (NO2) in the atmosphere. Under the condition of heavily polluted weather, aerosol has a serious influence on the concentration inversion of NO2. In this paper, using both echoes of SO2 and NO2 at weak absorption wavelengths (301.50 nm and 446.60 nm) in differential absorption lidar, the aerosol extinction coefficient and backscattering coefficient are calculated by recursive inversion algorithm. It is also used to correction the concentration distribution of NO2 on the detective path. The experimental results show that the standard deviation of NO2 concentration distribution using the correction algorithm is less than 10 mu g/m(3), and the fluctuation range is less than that of direct inversion. This concentration inversion algorithm overcomes the uncertainty caused by the assumption of the boundary value at the reference point when using the single-wavelength Klett or Fernald backward integration method to invert the aerosol extinction coefficient in heavily polluted weather, and has higher accuracy.