Demonstration of aerosol profile measurement with a dual-wavelength high-spectral-resolution lidar using a scanning interferometer.

Simple dual-wavelength high-spectral-resolution lidar at 355 and 532 nm with a scanning interferometer was developed for continuous observations of aerosol profiles. Scanning the interferometer periodically over a range of one fringe at 532 nm (1.5 fringes at 355 nm) enabled recording of range-resolved interference signals at these two wavelengths.

355-nm direct-detection Doppler wind lidar for vertical atmospheric motion measurement.

A compact and simple 355-nm direct-detection Doppler wind lidar (DDDWL) was developed to measure the line-of-sight (LOS) wind speed of the background atmosphere from atmospheric molecule return signals with and without aerosols and clouds. A receiver design with a Fabry-Perot etalon interferometer (FPEI) without an inside deposited step coating or fiber coupling is considered for the DDDWL using the double-edge technique. The receiver with the double-edge technique uses a FPEI and wedge prism to form a double-edge filter.

Possible use of fluorescence from iodine blocking filter in high-spectral-resolution lidar to detect Mie scattering signals.

The detection of atmospheric backscattering signals using fluorescence from an iodine blocking filter in high-spectral-resolution lidar was studied experimentally. The efficiency of detection is determined by the fluorescence quantum efficiency and the optical efficiency of collecting fluorescence. The quantum efficiency was estimated to be ${\sim}{0.

Impacts of local versus long-range transported aerosols on PM concentrations in Seoul, Korea: An estimate based on 11-year PM and lidar observations.

Extreme haze episodes have frequently occurred in Seoul since mid-2010s by the combined contributions of transboundary transported aerosols as well as locally emitted pollutants. In this study, we developed a novel method to estimate the contribution of long-range transport (LRT, aerosols are transported from any regions except local area near Seoul) and local pollution (LP, aerosols are originated from local area near Seoul) cases to the PM concentration in Seoul, Korea, using the PM concentration ratio between surface (PM) and mountaintop (PM) sites and the lidar-derived mixing layer height. The overall contributions of LRT and LP events to nighttime high-PM episodes (PM > 50 μg m) during the period of May 2008-April 2019 were estimated to be approximately 32% and 47%, respectively.

Development of a 355-nm high-spectral-resolution lidar using a scanning Michelson interferometer for aerosol profile measurement.

A simple 355-nm high-spectral-resolution lidar (HSRL) is developed for continuous observation of aerosol profiles. A scanning Michelson interferometer is used to separate the Rayleigh and Mie scattering components. The interferometer is periodically scanned in the range of one fringe.

Measurement of water mist particle size generated by rocket launch using a two-wavelength multi-static lidar.

Water mist generated during a rocket launch is thought to protect the rocket and payloads from acoustic noise. The size of mist particles is essential to understanding the effect on noise reduction. A two-wavelength multi-static lidar was developed for measuring water mist size at the launch site.

Measurement method of high spectral resolution lidar with a multimode laser and a scanning Mach-Zehnder interferometer.

A simple high spectral resolution lidar technique using a multi-longitudinal mode laser is proposed for measuring aerosol extinction and backscattering coefficients. A scanning interferometer having the same free spectral range as the mode spacing of the laser is used to separate Rayleigh from Mie scattering. Scanning the interferometer in the span of one fringe, the lidar signals at the minimum and maximum Mie-scattering transmission are measured.

Real-time observational evidence of changing Asian dust morphology with the mixing of heavy anthropogenic pollution.

Natural mineral dust and heavy anthropogenic pollution and its complex interactions cause significant environmental problems in East Asia. Due to restrictions of observing technique, real-time morphological change in Asian dust particles owing to coating process of anthropogenic pollutants is still statistically unclear. Here, we first used a newly developed, single-particle polarization detector and quantitatively investigate the evolution of the polarization property of backscattering light reflected from dust particle as they were mixing with anthropogenic pollutants in North China.

Development of a multiple-field-of-view multiple-scattering polarization lidar: comparison with cloud radar.

We developed a multiple-field-of-view multiple-scattering polarization lidar (MFMSPL) to study the microphysics of optically thick clouds. Designed to measure enhanced backscattering and depolarization ratio comparable to space-borne lidar, the system consists of four sets of parallel and perpendicular channels mounted with different zenith angles. Depolarization ratios from water clouds were large as observed by MFMSPL compared to those observed by conventional lidar.

Fluorescence from atmospheric aerosols observed with a multi-channel lidar spectrometer.

A lidar for measuring fluorescence from atmospheric aerosols was constructed with a third harmonic Nd:YAG laser, a 1-m diameter telescope, and a 32-channel time-resolved photon-counting spectrometer system. Fluorescence spectrum and vertical distribution of fluorescent aerosols in the lower atmosphere were observed during the nighttime with excitation at 355 nm. Relatively strong broad fluorescence was observed from Asian dust and air-pollution aerosols transported from urban and industrial areas.