The Determination of Aerosol Distribution by a No-Blind-Zone Scanning Lidar

Abstract

A homemade portable no-blind zone laser detection and ranging (lidar) system was designed to map the three-dimensional (3D) distribution of aerosols based on a dual-field-of-view (FOV) receiver system. This innovative lidar prototype has a space resolution of 7.5 m and a time resolution of 30 s. A blind zone of zero meters, and a transition zone of approximately 60 m were realized with careful optical alignments, and were rather meaningful to the lower atmosphere observation. With a scanning platform, the lidar system was used to locate the industrial pollution sources at ground level. The primary parameters of the transmitter, receivers, and detectors are described in this paper. Acquiring a whole return signal of this lidar system represents the key step to the retrieval of aerosol distribution with applying a linear joining method to the two FOV signals. The vertical profiles of aerosols were retrieved by the traditional Fernald method and verified by real-time observations. To effectively and reliably retrieve the horizontal distributions of aerosols, a composition of the Fernald method and the slope method were applied. In this way, a priori assumptions of even atmospheric conditions and the already-known reference point in the lidar equation were avoided. No-blind-zone vertical in-situ observation of aerosol illustrated a detailed evolution from almost 0 m to higher altitudes. No-blind-zone detection provided tiny structures of pollution distribution in lower atmosphere, which is closely related to human health. Horizontal field scanning experiments were also conducted in the Shandong Province. The results showed a high accuracy of aerosol mass movement by this lidar system. An effective quantitative way to locate pollution sources distribution was paved with the portable lidar system after validation by the mass concentration of suspended particulate matter from a ground air quality station.

Development of ZJU High-Spectral-Resolution Lidar for Aerosol and Cloud: Extinction Retrieval

“…It indicates that the standard method is not suitable for the further aerosol analysis under the condition of low SNR, which is sensitive to the extinction coefficient errors, such as the feature classification, the retrieval of microphysical properties, etc. [34]. The relative biases of profile 48 (the second profile) from the IIR method at the start of "feature" may be caused by the system constant and the initial value of the lidar ratio.…”

Optimization of Auxiliary Biaxial Receiver to Detect Blind Zone of Pulsed Coherent Wind Lidar

“…The color bar represents the goal function value. For the general MCT system as Table 1 shows, the suitable range of all the parameter sequences of the ABR system is set as Equation (16)(17)(18)(19)(20). The offset distance is still determined by…”

“…However the coding system has a lower magnitude of the power spectrum, compared with a non-coding system [16], so the effective detection distance of the coding system is limited. Wang [19] realizes a dual optical receiving direct detecting lidar system to solve the blind zone problem caused by the system geometry factor of the transceiver allograft. Eric P. Magee [17,18] demonstrated the feasibility of the bistatic coherent lidar system.…”

Development of a versatile lidar system based on passively Q-switched Nd: YAG laser for monitoring aerosols and cirrus clouds in the atmosphere

“…We assume that in the entire horizontal range, the medium is homogeneous [8,19,34,35]. The backscatter coefficient β and extinction coefficient ρ are considered constant in all range of lidar signals.…”