Surface Aerosol Properties Studied Using a Near-Horizontal Lidar

Abstract

Studying near-surface aerosol properties is of importance for a better assessment of the aerosol effect on radiative forcing. We employ the data from a near-horizontal lidar to investigate the diurnal behavior of aerosol extinction and single scattering albedo (SSA) at 349 nm. The response of these parameters to ambient relative humidity (RH) is examined for the data from a one-month campaign conducted in Chiba, Japan, during November 2017, a transition period from fall to winter. The Klett method and adaptive slope method are used in deriving the aerosol extinction coefficient from the lidar data, while the SSA values are retrieved using an aethalometer. Also, a visibility-meter is used to examine the aerosol loading inside the atmospheric boundary layer. It is found that the aerosol growth during the deliquescence phase is more readily observed than the contraction in the efflorescence phase. The decrease of SSA before the deliquescence RH is found for approximately 46% of the deliquescence cases, presumably representing the particle shrinkage of soot particles.

Continuous observations from horizontally pointing lidar, weather parameters, and PM2.5: a pre-deployment assessment for monitoring radioactive dust in Fukushima, Japan

“…The slope method is used by fitting a line between the maximum and minimum of the natural logarithm of the range-corrected signal between 100 m and 300 m. A homogeneous atmosphere can be assumed during the observation period in this horizontal range. This method is similar to our group's work that examined the relationship between horizontal lidar and weather effects from continuous lidar observations in November 2017 and in the winter of 2018 (Ong et al, 2019;Xiafukaiti et al, 2020). The depolarization ratio from the lidar signals is calculated as the ratio of the S and P signals multiplied by the ratio of the gains of the channels.…”

Vertical and near-horizontal scanning lidar observations of aerosol loads over Sofia, Bulgaria, in the presence of Saharan dust

“…Near-surface atmospheric measurements over urban areas aimed at assisting the air-quality monitoring attain increasing societal significance due to the strong and direct impact on the human health of aerosol pollutions (natural or anthropogenic) in the low troposphere. The horizontal or near-horizontal lidar scanning/mapping is an effective approach to detecting aerosol loads over broad areas and characterizing them in terms of local density and temporal dynamics [15][16][17].…”

“…The aerosol content of the air directly on the surface is monitored by local in situ measuring stations of aerosol concentration (PM10 and PM2.5). However, lidars with (quasi)horizontal scanning of the probing laser beam have become indispensable tools when one needs fast (including real-time) and accurate measurement, initial characterization, visualization and mapping of the aerosol density distribution over large areas (up to tens of square kilometers) [15][16][17].…”

Black carbon aerosol number and mass concentration measurements by picosecond short-range elastic backscatter lidar

“…Generally, EBL instruments are rarely used for short-range applications due to an incomplete overlap between the outgoing laser beam and the receiver field-of-view. Environmental and air quality applications [29][30][31][32][33][34][35] have recently raised a need for aerosol characterization close to the emission source, which is driving a decreasing to the minimal measurement-range in EBL technology.…”