Xianxin Li

Observations of marine aerosol using a scanning micro pulse Lidar in 2015

The observations of marine aerosol over the Yellow Sea near Qingdao were carried out using a ship-borne scanning micro pulse lidar (SMPL) onboard the oceanographic research vessel, XIANGYANGHONG No.8 (XYH-08). The observation campaign including anchor point observation and sailing observation was conducted from September 13th to September 18th, 2015. We acquired observation data of sailing route including aerosol extinction coefficient, the temporal and spatial variation of aerosols and clouds, and the structure of boundary layer and so on. Through the function of 3-dimensional scanning, the SMPL also provided range-height indication (RHI) and plane-position indication (PPI) of observation signals which could well reflect the distribution of marine aerosol in different directions. From the change of aerosol extinction coefficient, we successfully captured a process of sea fog occurrence.

Traffic trace gases measurements by long-path DOAS over a busy urban road in Qingdao

Observations of traffic trace gases near-surface concentration over a busy urban road in Qingdao were conducted by long-path differential optical absorption spectroscopy (LP-DOAS). During the observation period, the LP-DOAS system made long-term trace gases measurements over the Haier Road in Laoshan District, Qingdao. And a camera was placed next to the LP-DOAS system to record the traffic condition every day. The relationship between the trace gases measurements results and the traffic flow is presented in this paper. The weekly characteristics of the trace gases due to traffic influence are further studied in this paper. Using typical data on January 3 and March 22, 2018, the NO2 concentration is under a strong positive correlation with the traffic flow, and O3 concentration is under a negative correlation with the traffic flow. The correlation coefficient between NO2 measurements and traffic flow from 7:00 to 18:00 is 0.86. The comparison of daily measurements during a week showed that the working days had much more trace gases content than the weekend which may be affected by the different traffic condition among working days and the weekend.

Ship-borne MAX-DOAS sailing measurements of marine boundary layer trace gases over the offshore sea area near Huangdao

Observations of marine boundary layer trace gases vertical column density (VCD) over the offshore sea area near the Yellow Sea were conducted by ship-borne Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) carried by a Chinese oceanography research vessel, XiangYangHong 08, during an offshore observation campaign, from 13 September 2015 to 18 September 2015. During the offshore observation campaign, the ship-borne MAX-DOAS system made a sailing measurement over the offshore sea areas near the Huangdao district, Qingdao city from 8:00 to 13:00 on 16 September 2015. Observation results of sailing measurement are shown in this paper. By combining geometric character of monitoring area and weather condition, it can be concluded from the sailing measurement results that the geographic conditions have a significant influence on offshore sea boundary layer trace gases content. The sailing measurement showed that the Huangdao offshore sea area boundary layer had much more NO2 and O3 content than other sea areas because the Huangdao offshore sea area is near urban area with surrounding high trace gases content which may be susceptible to human activities, such as traffic influence.

Optical properties of atmospheric aerosol from shipborne multiwavelength lidar measurements during the 2015 Yellow Sea Experiment

High spatial, temporal resolution and continuous measurement of atmospheric aerosols over ocean is very important to understand their role in the atmospheric processes as well as on human health and environment. A shipborne multiwavelength lidar system for aerosol and clouds in the troposphere and lower stratosphere was developed. We then conducted twice shipborne measurements onboard the vessel XIANGYANGHONG No. 8 (X8) over the Yellow Sea of China on May and September in 2015, respectively. In this paper, the optical properties of aerosol together with 180- hour continuous measurement during the 2015 Yellow Sea Experiment (2015-YSE) are presented.

Marine boundary layer NO2 measurements by ship-borne MAX-DOAS during an offshore observation campaign, 2015

The observations of marine boundary layer NO2 vertical column density (VCD) over the yellow sea near Qingdao by ship-borne Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) were conducted with a Chinese oceanographic research vessel, XYH 08, during an offshore observation campaign, from 13 September 2015 to 18 September 2015. During the observation campaign, the ship-borne MAX-DOAS system made anchor point measurements in different sea areas including Qingdao coastal waters, the Yellow Sea, the Jiaozhou Bay and the Yangkou Bay area. Measurements results of anchor point measurements are presented in this paper. The air mass factor (AMF) errors caused by the vibration of the ship are also studied in this paper. Under good sea conditions on 14 September, the AMF errors of NO2 measurements caused by the ship vibration were evaluated to be less than 5%. By combining geometric character of monitoring area and weather condition, it can be concluded from the Jiaozhou Bay and the Yellow Sea measurement results that the meteorological conditions cause significant influence on local boundary layer NO2 content. The comparison of different anchor point measurements showed that the Jiaozhou Bay sea area had much more NO2 content than Yangkou sea area because the Jiaozhou Bay sea area is located in Qingdao urban area with surrounding NO2 contamination.

Observations of marine aerosol by a shipborne multiwavelength lidar over the Yellow Sea of China

Aerosol particles are important both because they affect atmospheric processes and, after deposition to the sea surface, because they affect processes in sea water. Aerosols have a strong impact on climate both due to scattering and absorption of incoming solar radiation (direct effect) and through their effects on cloud properties and associated cloud albedo (first indirect effect) and precipitation (second indirect effect). A shipborne multiwavelength Mie/Raman/Polarization aerosol lidar developed for marine aerosol is presented. The shipborne aerosol lidar (SAL) is able to measure aerosol backscatter and extinction coefficient as well as depolarization in the altitude range 0 to 20 km. The instrument is installed in a 2 m*2 m*2 m container. Preliminary results of investigation of marine aerosol properties on the basis of multiwavelength lidar onboard the Xiangyanghong Number 8 Research ship on the Yellow Sea and Jiaozhou Bay of China are presented.

Development of a scanning micro-pulse lidar for aerosol and cloud detection

A scanning micro-pulse lidar (MPL) was developed by Institute of Oceanographic Instrumentation, Shandong Academy of Sciences, which can be used for routine observations of optical properties, temporal and spatial variation of atmospheric aerosol and cloud in the lower troposphere. In addition to the optical system design, the design of 3 dimensional (3-D) scanning system controlled by servo motors is analyzed, including servo motor selection and mechanical design. Through the measurements in Qingdao, it is proved that 3-D scanning system can control the lidar azimuth/elevation scanning with high precision. The lidar has good performance and can provide time-height indication (THI), range-height indication (RHI) and plane-position indication (PPI) of lidar signals which can well reflect the temporal and spatial variation of atmospheric aerosol.

Observations of atmospheric trace gases by MAX-DOAS in the coastal boundary layer over Jiaozhou Bay

Atmospheric trace gases exist in the atmosphere of the earth rarely. But the atmospheric trace gases play an important role in the global atmospheric environment and ecological balance by participating in the global atmospheric cycle. And many environmental problems are caused by the atmospheric trace gases such as photochemical smog, acid rain, greenhouse effect, ozone depletion, etc. So observations of atmospheric trace gases become very important. Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) developed recently is a kind of promising passive remote sensing technology which can utilize scattered sunlight received from multiple viewing directions to derive vertical column density of lower tropospheric trace gases like ozone, sulfur dioxide and nitrogen dioxide. It has advantages of simple structure, stable running, passive remote sensing and real-time online monitoring automatically. A MAX-DOAS has been developed at Shandong Academy of Sciences Institute of Oceanographic Instrumentation (SDIOI) for remote measurements of lower tropospheric trace gases (NO2, SO2, and O3). In this paper, we mainly introduce the stucture of the instrument, calibration and results. Detailed performance analysis and calibration of the instrument were made at Qingdao. We present the results of NO2, SO2 and O3 vertical column density measured in the coastal boundary layer over Jiaozhou Bay. The diurnal variation and the daily average value comparison of vertical column density during a long-trem observation are presented. The vertical column density of NO2 and SO2 measured during Qingdao oil pipeline explosion on November 22, 2013 by MAX-DOAS is also presented. The vertical column density of NO2 reached to a high value after the explosion. Finally, the following job and the outlook for future possible improvements are given. Experimental calibration and results show that the developed MAX-DOAS system is reliable and credible.

Design and development of multiwavelength Mie-Polarization-Raman aerosol lidar system

Atmospheric aerosols play a major role in many atmospheric processes concerning the earth’s radiation budget, air quality, clouds and percipitation, and atmospheric chemistry. A multiwavelength Mie-Polarization-Raman lidar system is developing at Shandong Academy of Sciences Institute of Oceanorgraphic Instrumentation (SDIOI), which is used for the profiling of optical and physical aerosol properties. This system is specifically designed for characterizing marine aerosol which consists of a complex mix of different aerosol types. The aerosol lidar consists of a tripled Nd:YAG laser with three wavelengths, 30 cm telescope, six receiver channels and data acquistion subsystem. It provides particle backscatter coefficients at 355, 532 and 1064 nm (3β), extinction coefficients at 355 and 532 nm (2α), and depolarization ratio (σ). There are two Raman channels to collect the Raman signals backscattered by nitrogen molecules at 607 nm and by water vapor moecules at 407 nm. In this paper, we mainly describe the details of the optical setup, structure and performance of the lidar system. At last, the simulated signals based on the specifications are presented to demonstrate the capabilities of the lidar system.