Investigation of the Vertical Distribution of TroposphericAerosol Layers from Multifrequency Laser Sensing Data.Part 2: The Vertical Distribution of Optical Aerosol Characteristicsin the Visible Region

摘要

Regular lidar measurements of the vertical aerosol distribution were conducted in Tomsk (56° N, 85° E) from March 2006 to October 2007 as part of the CISLINET (CIS Lidar Network) project. The statis-tical analysis of the profiles of the aerosol backscattering coefficients β_a (532 nm), extinction coefficients σ_a (532 nm), and lidar ratio S_a (532 nm) from the data of nocturnal measurements by Raman lidar (532 and 607 nm) in the altitude range from 0.45 to 7 km is presented. According to these measurements, the mean height of the top boundary of the boundary layer (BL) is 1.22 km for the cold period of observations (from October to March) and 2.3 km for the warm period (from April to September). The mean value of σ_a (532 nm) for the cold period of observations in the BL is 0.025 km~(-1), which is more than two times lower than the mean value of 0.061 km~(-1) for the warm observation period. The mean value of S_a (532 nm) in the BL is independent of the observation season and is equal to 52 sr. Above the BL, in the free troposphere (FT), the coefficients β_a (532 nm) and β_a (532 nm) are proportional to the molecular scattering coefficient. The mean value of σ_a (532 nm) is 0.0083 km~(-1) for the cold period and 0.011 km~(-1) for the warm period. The lidar ratio in the FT is 43.5 sr in the cold period. This value is nearly 10 sr lower than the mean lidar ratio for the warm period (52.8 sr).