Optimization of Mach-Zehnder interferometer of high-spectral-resolution lidar for large-scale wind measurement.

The optimization design of a quadri-channel Mach-Zehnder interferometer (QMZI) of the high-spectral-resolution lidar is presented for the large-scale wind measurement. The optimized QMZI can discriminate the Doppler frequency shift generated by atmospheric wind from aerosol Mie scattering echo signals and molecular Rayleigh scattering echo signals, and then the wind information can be retrieved. The optimal optical path differences (OPDs) of QMZI are determined by theoretical and simulation analysis. The wind measurement simulation experiments prove that the designed QMZI can measure the large-scale wind with an accuracy of meter level.

Lateral scanning Raman scattering lidar for accurate measurement of atmospheric temperature and water vapor from ground to height of interest: publisher's note.

This publisher's note contains corrections to Opt. Lett.48, 2595 (2023).10.1364/OL.488924.

Lateral scanning Raman scattering lidar for accurate measurement of atmospheric temperature and water vapor from ground to height of interest.

A novel lateral scanning Raman scattering lidar (LSRSL) system is proposed, aiming to realize the accurate measurement of atmospheric temperature and water vapor from the ground to a height of interest and to overcome the effect of a geometrical overlap function of backward Raman scattering lidar. A configuration of the bistatic lidar is employed in the design of the LSRSL system, in which four horizontally aligned telescopes mounted on a steerable frame to construct the lateral receiving system are spatially separated to look at a vertical laser beam at a certain distance. Each telescope, combined with a narrowband interference filter, is utilized to detect the lateral scattering signals of the low- and high-quantum-number transitions of the pure rotational Raman scattering spectra and vibrational Raman scattering spectra of N2 and H2O. The profiling of lidar returns in the LSRSL system is performed by the elevation angle scanning of the lateral receiving system, in which the intensities of the lateral Raman scattering signals at each setting of elevation angles are sampled and analyzed. Preliminary experiments are carried out after the construction of a LSRSL system in Xi'an city, whose retrieval results and statistical error analyses present a good performance in the detection of atmospheric temperature and water vapor from the ground to a height of 1.11 km and show the feasibility for combination with backward Raman scattering lidar in atmospheric measurement.

Storage method of multi-channel lidar data based on tree structure.

The multi-channel lidar has fast acquisition speed, large data volume, high dimension, and vital real-time storage, which makes it challenging to be met using the traditional lidar data storage methods. This paper presents a novel approach to storing the multi-channel lidar data based on the principle of the tree structure, the adjacency linked list, the binary data storage. In the proposed system, a tree structure is constructed by the four-dimensional structure of the multi-channel lidar data, and a data retrieval method of the multi-channel lidar data file is given. The results show that the proposed tree structure approach can save the storage capacity and improve the retrieval speed, which can meet the needs for efficient storage and retrieval of multi-channel lidar data, and improve the data storage utilization and the practicality of multi-channel lidar system.

Development of an Automatic Polarization Raman LiDAR for Aerosol Monitoring over Complex Terrain.

High temporal and spatial resolution profiling of aerosol properties is required to study air pollution sources, aerosol transport, and features of atmospheric structures over complex terrain. A polarization Raman LiDAR with remote operation capability was developed for this purpose and deployed in the Vipava Valley, Slovenia, a location in the Alpine region where high concentrations of aerosols originating from a number of different local and remote sources were found. The system employs two high-power Nd:YAG pulsed lasers at 355 nm and 1064 nm as transmitters and provides the capability to extract the extinction coefficient, backscatter coefficients, depolarization ratio, Ångström exponent, and LiDAR ratio profiles. Automatized remote operation in an indoor environment provides a high duty cycle in all weather conditions. In addition to the detailed description of the device, an assessment of its potential and the retrieval uncertainties of the measured quantities is discussed. System optimization and performance studies include calibration of the depolarization ratio, merging of near-range (analog) and far-range (photon counting) data, determination of overlap functions, and validation of the retrieved observables with radiosonde data. Two cases for assessing LiDAR performance under specific weather conditions (during rain and in the presence of mineral dust) are also presented.