Yiyun Li

Mobile lidar system for environmental monitoring

A versatile mobile optical remote sensing system utilizing light detection and ranging (lidar) technology has been constructed and adapted for multidisciplinary environmental monitoring tasks on the Chinese scene. A key application is differential absorption lidar (DIAL) monitoring of distributions of gaseous air pollutants. The system includes a 20 Hz Nd:YAG laser-pumped dye laser, and two vertically looking Newtonian telescopes with diameters of 40 and 30 cm, respectively, over which folding mirrors can be hoisted over the laboratory roof to interrogate the remote target area. Using harmonic pulses from the Nd:YAG laser, remote laser-induced fluorescence (LIF) and laser-induced break-down spectroscopy (LIBS) can be performed. In this way, also water pollutants, vegetation, and soils can be studied. The wide applicability of the new system is illustrated in long-range measurements of atmospheric mercury and sulfur dioxide, and in LIF and LIBS monitoring. Remote passive monitoring of flying insects illustrates the additional functionality of the system.

Laser spectroscopy applied to environmental, ecological, food safety, and biomedical research

Laser spectroscopy provides many possibilities for multi-disciplinary applications in environmental monitoring, in the ecological field, for food safety investigations, and in biomedicine. The paper gives several examples of the power of multi-disciplinary applications of laser spectroscopy as pursued in our research group. The studies utilize mostly similar and widely applicable spectroscopic approaches. Air pollution and vegetation monitoring by lidar techniques, as well as agricultural pest insect monitoring and classification by elastic scattering and fluorescence spectroscopy are described. Biomedical aspects include food safety applications and medical diagnostics of sinusitis and otitis, with strong connection to the abatement of antibiotics resistance development.

Lidar mapping of atmospheric atomic mercury in the Wanshan area, China

A novel mobile laser radar system was used for mapping gaseous atomic mercury (Hg0) atmospheric pollution in the Wanshan district, south of Tongren City, Guizhou Province, China. This area is heavily impacted by legacy mercury from now abandoned mining activities. Differential absorption lidar measurements were supplemented by localized point monitoring using a Lumex RA-915M Zeeman modulation mercury analyzer. Range-resolved concentration measurements in different directions were performed. Concentrations in the lower atmospheric layers often exceeded levels of 100 ng/m3 for March conditions with temperature ranging from 5 °C to 20 °C. A flux measurement of Hg0 over a vertical cross section of 0.12 km2 resulted in about 29 g/h. Vertical lidar sounding at night revealed quickly falling Hg0 concentrations with height. This is the first lidar mapping demonstration in a heavily mercury-polluted area in China, illustrating the lidar potential in complementing point monitors.

Optical characterization of Chinese hybrid rice using laser-induced fluorescence techniques—laboratory and remote-sensing measurements: publisher’s note

This publishers note corrects the author listing and a figure caption in Appl. Opt.57, 3481 (2018)APOPAI0003-693510.1364/AO.57.003481.

Laser Spectroscopy applied to Environmental, Ecological, Agricultural and Food Safety Research

Laser spectroscopy has a multitude of applications of importance to human and ecosystem well-being, such as in the environmental, ecological, agricultural and food safety areas. Recent work, mostly from SCNU, will be reviewed.

Differential absorption lidar monitoring of atmospheric atomic mercury in China using a novel mobile system

Mercury is a severe pollutant in China. A novel mobile laser spectroscopy laboratory was constructed and used in differential absorption lidar mapping in major Chinese cities, a heavily polluted mining area and an archeological site.