A method is given to calculate the atmospheric vertical visibility profile through the extinction coefficient which provided from the Level 2 aerosol optical products of CALIPSO spaceborne lidar. Five visibility profiles during haze around Shanghai (3 for daytime and 2 for nighttime) were analyzed in this paper to reveal vertical distribution characteristics during haze and non-haze period. Results show that vertical visibility during the haze period is from 0 to 3km where aerosols were mainly concentrated in the haze layer. The mean thickness of aerosol layer whose visibility is less than 10km was 2.27km, and the vertical height shows characteristics of both uniform and non-uniform distributions. During the non-haze period, less aerosols were distributed in the atmosphere so that there was a significantly higher vertical visibility than in haze cases.
The data from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite was used to
analyze the aerosol micro-physical properties over Beijing and surrounding area during haze periods from 2007 to 2008
in this paper. The results showed as follows. The values of TABC (total attenuated backscatter coefficient) for aerosols
accounted for about 25% with varying altitudes. The aerosol scattering ability little changed from 0-4 km, showing that
the aerosol layer evenly distribute. At different altitude ranges (0-1, 1-2, 2-3 and 3-4 km above ground level), values of
TABC almost concentrate in the range of 2.5×10-3 -4.5×10-3 km-1.sr-1. In spring, summer and winter, aerosol scattering
has the similar variation, with the maximum of TABC ranging from 3.5×10-3 km-1.sr-1 to 4.5×10-3 km-1.sr-1, while the
maximum of TABC in autumn is from 1.5×10-3 km-1.sr-1 to 2.5×10-3 km-1.sr-1. Aerosol shape and size are characterized by
VDR (volume depolarization ratio) and TACR (total attenuated color ratio). Aerosols with VDR greater than 10% were
more than the ones with VDR less than 10% at the same altitude range. Notably, aerosols with smaller VDR (0-10%)
appeared more frequently in autumn than those in the other three seasons. For each altitude range, aerosols with TACR
ranging from 0-0.2 contributed much more than those with TACR ranging from 1.8-2.0. The size of aerosols in summer
was the largest and that in autumn was the smallest in middle and lower troposphere.
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