The vertical stratification and optical characteristics of aloft aerosol plumes are critical to evaluate their influences on climate radiation and air quality. In this study, we demonstrate the synergistic measurements of aloft aerosol plumes by a ground-based NOAA-CREST lidar network (CLN) along the US East Coast, the AERONET-sun/sky radiometer network at lidar sites, and satellite observations. During the plume intrusion period on March 6, 2012, the CLN and AERONET measurements were consistent in illustrating the onset of dust aerosol plumes. We observed two-layers of aerosol located at 1.0 ~ 8.0 km altitude. The column-average volume size distributions show increasing concentration of both fine- and coarse-modes aerosols, but are dominated by the coarse-mode. Direct lidar inversions illustrate that the aerosol plume layers contributed up to 70% of the total AOD. NOAA-HYSPLIT back-trajectories and CALIPSO observations indicate the trans-Pacific transport of Asian-dust at 3 - 8 km altitude to the US East Coast. Meanwhile, the NOAA-HMS fire and smoke products illustrate the transport and possible mixture of dust with fine-mode smoke particles from the middle and southwestern US. The small Angstrom exponents of MODIS/Aqua in the US East Coast imply the dominance of coarse-mode particles. Accordingly, the upper layer of coarse mode aerosols is most likely transported from the East Asia, while the lower layer at 1-3 km altitude probably consists of continental dust particles from the western US mixed with fine-mode smoke particles. In addition, the transport and vertical structure of aerosol are investigated with the NAAPS global aerosol transport model.
Atmospheric aerosols have a significant impact on climate change through the scattering and absorption of incoming
solar and outgoing thermal radiation. The aerosol optical properties can be directly measured using an elastic-Raman
lidar. However, extraction of the extinction coefficient from the optical depth profile requires the use of numerical
differentiation with these lidars, which suffers the random and systematic noises limitation and thereby reducing the
detection sensitivity and accuracy. A new method to improve the quality of Raman lidar data processing is presented.
Compared to the conventional method, the proposed method has the advantage, which can directly retrieve the aerosol
extinction coefficients without numerical differentiation. Trial values of lidar ratio (from 10 to 90 sr with an increment of
1 sr) are applied to Fernald solution of the elastic lidar signals at 354.7 nm and all aerosol backscatter coefficients are
obtained. The exact aerosol backscatter coefficients retrieved by combing elastic and Raman signals are used as
constrain of these results of Fernald method to determine aerosol true lidar ratios as well as extinction coefficients. The
numerical simulations demonstrated that the proposed method provides good accuracy and resolution of aerosol profile
retrievals. And the method is also applied to elastic-Raman lidar measurements at the Hampton University, Hampton,
Lidar backscatter signal resulting from laser light scattering from the aerosol and molecular in the atmosphere contains
various information about the geometrical and physical properties of aerosol and molecular. The lidar backscatter signal
can provide information about the planetary boundary layer (PBL) stratification by using aerosol as a tracer for
convective and mixing processes. A PBL height and structure detecting technique based on the fractal dimension of
three-wavelength backscatter signals is advanced. In this PBL height detecting technique, the three-wavelength
backscatter signals are obtained by the Hampton University (HU, 37.02° N, 76.33° W) lidar. The fractal dimension was calculated using the three-wavelength lidar signals. The PBL heights obtained from fractal dimension of threewavelength
lidar signals is compared with PBL heights obtained from the potential temperature profiles which are
provided by NASA Langely Research Center (10 miles from HU). And results of the two methods agree well. Moreover,
fractal dimension method can reduce the influence of the geometrical form factor on the PBL detecting to expand the
detecting range of PBL and remove the effect of plume. Also, the fractal dimension method can show the PBL dynamics
and the PBL evolution clearly.