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By using a charge-coupled device (CCD) as the detector, side-scatter lidar has great potential applications in the near range atmospheric detection. A new inversion method is proposed for CCD side-scatter lidar (Clidar) to retrieve aerosol phase function and vertical backscattering coefficient. Case studies show the retrieved results from Clidar are in good agreements with those obtained from other instruments. It indicates that the new proposed inversion method is reliable and feasible and that the Clidar is practicable.

Over the past three decades, China has seen aerosol levels substantially surpass the global average, significantly impacting regional climate. This study investigates the long-term and seasonal variations of aerosols in the Huai River Basin (HRB) using MODIS, CALIOP observations from 2007 to 2021, and ground-based measurements. A notable finding is a significant decline in the annual mean Aerosol Optical Depth (AOD) across the HRB, with MODIS showing a decrease of approximately 0.023 to 0.027 per year, while CALIOP, which misses thin aerosol layers, recorded a decrease of about 0.016 per year. This downward trend is corroborated by improvements in air quality, as evidenced by PM2.5 measurements and visibility-based aerosol extinction coefficients. Aerosol decreases occurred at all heights, but for aerosols below 800 m, with an annual AOD decrease of 0.011. The study also quantifies the long-term trends of five major aerosol types, identifying Polluted Dust (PD) as the predominant frequency type (46%), which has significantly decreased, contributing to about 68% of the total AOD reduction observed by CALIOP (0.011 per year). Despite this, Dust and Polluted Continental (PC) aerosols persist, with PC showing no clear trend of decrease. Seasonal analysis reveals aerosol peaks in summer, contrary to surface measurements, attributed to variations in the Boundary Layer (BL) depth, affecting aerosol distribution and extinction. Furthermore, the study explores the influence of seasonal wind patterns on aerosol type variation, noting that shifts in wind direction contribute to the observed changes in aerosol types, particularly affecting Dust and PD occurrences. The integration of satellite and ground measurements provides a comprehensive view of regional aerosol properties, highlighting the effectiveness of China's environmental policies in aerosol reduction. Nonetheless, the persistence of high PD and PC levels underscores the need for continued efforts to reduce both primary and secondary aerosol production to further enhance regional air quality. [ABSTRACT FROM AUTHOR]

The near-ground aerosols have the most impact on the human beings. Its fine spatial and temporal distribution, with which the environmental and meteorological departments concern themselves most, has not been elaborated very well due to the unavailable measurement tools. We present the continuous observations of the vertical profile of near-ground aerosol backscattering coefficients by employing our self-developed side-scattering lidar system based on charge-coupled device camera. During the experimental period from April 2013 to August 2014, four catalogs of aerosol backscattering coefficient profiles are found in the near ground. The continuous measurement is revealed by the contour plots measured during the whole night. These experimental results indicate that the aerosol backscattering coefficients in near ground are inhomogeneous and vary with altitude and time, which are very useful for the model researchers to study the regional air pollution and its climate impact. [ABSTRACT FROM AUTHOR]

The new side‐scattering lidar using two charge‐coupled device cameras and one CW laser is developed to measure the near‐ground aerosol profiles in haze day, which is a powerful tool and is most interested for the environmental and meteorological agencies. A new inversion method for the side‐scattering lidar to retrieve the aerosol backscattering coefficient is proposed for the first time, which is based on the aerosol backscattering coefficient measured by itself at the ground as a constrained condition. Numerical simulation is carried out to analyze the convergence of this new method. Case studies indicate that this method is reasonable and feasible. The method is especially suitable for the measurement in the foggy and hazy weathers even during the daytime, and it does not need a simultaneous backscattering lidar as the reference any more. Plain Language Summary: The CCD lidar is a new technique for aerosol observation in haze day; it is different from traditional backscattering lidar. For one thing, the detecting of aerosol profiles near the ground is really improved by this CCD lidar because there is no overlap function, instead of the traditional lidar. For another thing, we use two CCD in this system, and the calibration problem will be easily solved by itself. So, the CCD lidar will be a very useful tool with its low cost in the future. Key Points: A new low‐cost CCD lidar is developed for haze measurement in day and night time, and it is quite useful tool the environmental and meteorological fieldsA new inversion method for this CCD lidar to retrieve the aerosol backscattering coefficient is proposed, and it does not need another simultaneous instrument as the reference any moreThe system and its inversion method have been proved by numerical simulation and experimental study [ABSTRACT FROM AUTHOR]

The scanning polarization Mie lidar (SPML) system has been developed and is described. The lidar system has two detection channels to receive the parallel and perpendicular polarization components at the laser wavelength of 532 nm, which indicates the nonsphericity of aerosol and cloud particles. It can take the horizontal, vertical and conical scans of the atmosphere with the elevation and azimuth motors. This paper discusses the current capability of the SPML lidar and its results. The observation shows that the SPML lidar can provide the multi-dimensional views of the atmosphere which is impossible to achieve with other ground-based vertically pointing lidars. It is helpful to track and monitor aerosol plumes in urban area, to determinate the planetary boundary layer height and to enhance the measurement of atmosphere in the lower height where the geometrical form factor of lidar system affects. [ABSTRACT FROM AUTHOR]

To explore the vertical distribution of the aerosol optical parameters over Jinhua City, southeast China, a Dual-wavelength Mie Polarization Raman Lidar (DMPRL) system was operated to obtain the atmospheric backscattering signals from June 2013 to May 2014. Profiles of aerosol occurrence frequency and aerosol optical parameters, including backscattering ratio, particle depolarization ratio, and color ratio, were retrieved from the lidar signals. The cases with a cloud base below 6 km and profiles on rainy days were eliminated. The multi-layer vertical aerosol structure was found in Jinhua area and the altitude-resolved optical properties varies with seasons. In autumn, winter and spring, the aerosol layer occurrence frequencies were higher than summer at 3–6 km, especially in spring. The mean particle depolarization ratio at 4–6 km exceeded 0.1 in autumn, winter, and spring, whereas it was <0.05 in summer. Aerosol with high color ratios appeared at 0–2 km in autumn. The analysis of one-year backward trajectories exhibits a dust dominating aerosol layer at 4–6 km in autumn, winter, and spring, a partially sea salt dominating aerosol layer at 0–2 km in autumn and a partially dust aerosol layer at 0–2 km in winter. Six cases were used to study the influence of aerosol advection and local sources vertical aerosol properties distribution. Through our analysis, aerosols at different altitudes are influenced by different sources, which are important for understanding the spatiotemporal characteristics of aerosol layers over Jinhua. The vertical distribution of aerosol properties in Jinhua area is affected by locally emitted aerosol , transported dust and ocean aerosol. • Multi-layer aerosol with corresponding properties observed by lidar over Jinhua. • High occurrences of aerosol layers were found at 3–6 km except summer. • Source-related aerosol vertical distribution dominated especially at 4–6 km. • Larger particles with high color ratios appeared at 0–2 km in autumn. • Regional and transported source aerosols affected the vertical aerosol properties. [ABSTRACT FROM AUTHOR]