In order to process the data and combine the advantages of these two methods, the aerosol fraction was introduced to the integrated algorithm; it is defined as the ratio of the number of aerosol bins identified byVFM product to the total number of bins in a backscatter profile.
Besides, the attenuated backscattered signals were averaged over a time period of 20 minutes and were normalized for data preprocessing.
Figure 6(c) shows the comparison of the vertical profiles of backscatter at 532 nm between CALIOP and CE370, as well as the PBL height estimated at the coincident point.
Cloud detection was performed for each profile of backscatter based on the observations by ground-based Lidar.
If the difference between the PBL height and TL height for a backscatter profile exceeds this threshold value, the aloft aerosol layer is found.
Because of the aloft aerosol layer overlying the PBL, the significant attenuation in the downward backscatter signals acquired from CALIOP can be found.
Due to the effects of clouds (especially the thick clouds) on the backscattered signals acquired from space-borne CALIOP, the cloud elimination based on VFM data was adopted.
Richner, "Comparison between backscatter lidar and radiosonde measurements of the diurnal and nocturnal stratification in the lower troposphere," Journal of Atmospheric and Oceanic Technology, vol.
Hoff, "The detection of mixed layer depth and entrainment zone thickness from lidar backscatter profiles," Journal of Atmospheric and Oceanic Technology, vol.
Brooks, "Finding boundary layer top: application of a wavelet covariance transform to lidar backscatter profiles," Journal of Atmospheric and Oceanic Technology, vol.
(a) The total attenuated backscatter at 532 nm acquired by CALIOP, (b) result of the covariance transform for different wavelet dilations applied to the profile in (a), and (c) result of top heights of PBL derived from CALIOP and ground-based Lidar, respectively.
Caption: Figure 3: Vertical profiles of total attenuated backscatter at 532 nm; (a) was acquired from CALIOP, while (b) was acquired from ground-based Lidar (CE370), which were all measured on December 31,2015.