Chlorophyll-a (Chla) concentration data is one of the key parameters for the evaluation of water eutrophication and primary productivity. Compared with traditional monitoring methods, it has the advantages of quasi-real-time, largescale and long-term by using remote sensing data to retrieve Chla concentration data. Analyzing the temporal and spatial distribution of Chla concentration and its long time series changes will help relevant institutions to comprehensively evaluate and control the water environment. However, there is no consensus on the long-term change mechanism of Chla concentration in coastal waters. In this study, the Modis data from 2003 to 2009 was used to retrieve the Chla concentration data in the Bohai Sea and its temporal and spatial distribution characteristics were analyzed. In addition, the potential relationship between wind speed and Chla concentration was analyzed using Quick Scatterometer wind field data over the same time period. The results showed that there were different seasonality characteristics in different dynamic regions. The concentration of Chla was the lowest in summer in the Bohai Sea, and it showed an obvious interannual variation trend in summer and autumn in Laizhou Bay and Bohai Bay. The comparison results of wind speed and Chla showed that the seasonal changes of wind speed and Chla were consistent to some extent. It should be considered that the wind field of sea surface was one of the influencing factors of Chla change mechanism in the shallow sea ecological environment system.
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.
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.
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.
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