This paper reports on the use of a kite-based system for measuring low-altitude particulate matter (PM) concentrations over grassland in Inner Mongolia. The motivation came from PM-concentration measurements at height...This paper reports on the use of a kite-based system for measuring low-altitude particulate matter (PM) concentrations over grassland in Inner Mongolia. The motivation came from PM-concentration measurements at heights below 3 m over non-erodible surfaces which showed constant concentrations and made flux calculations relatively uncertain. One aim was the quantification of wind-driven matter fluxes across ecosystem boundaries, where the relevant layer can be assumed at heights below 100 m. Compared to other measurement techniques (e.g. LIDAR, towers and airborne systems) kite-based systems represent an inexpensive, highly flexible research tool which is well-suited for application in remote sites. The basis of the introduced system is a 4 m2 Parafoil kite which has enough lifting capacity to carry equipment of about 6 kg at wind velocities between 3 ms-1 to nearly 20 ms-1. A self-adjusting platform was constructed to balance moves and to carry a portable Environmental Dust Monitor (EDM), anemometer and a GPS receiver. So, all parameters necessary for a vertical profile of dust fluxes could be measured. In the first flights the applied kite-based dust profiling system (KIDS) was examined according to general technical application problems. Firstly, the influence of diverse surface characteristics, the flying condition and height-stability was tested. The result suggests that surface characteristics in general have a higher influence than the optimal wind velocity, which ranged from 9 ms-1 to 17 ms-1. Secondly, uncertainties in the measured data were quantified and assessed. The uncertainties in wind velocity measurements due to motion in horizontal and vertical direction were not higher than 0.45% - 0.65% and 1.8% - 2.2% during the kite ascent. The outcome of the study illustrates the suitable application of KIDS for low-altitude measurements in remote sites.展开更多
Aerosol acidity(pH)plays an important role in the multiphase chemical processes of atmospheric particles.In this study,we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coas...Aerosol acidity(pH)plays an important role in the multiphase chemical processes of atmospheric particles.In this study,we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coastal city of southeast China.We performed quantitative analysis on the various influencing factors on aerosol pH,and explored the responses of aerosol pH to different PM_(2.5)and O_(3)pollution levels.The results showed that the average aerosol pH was 2.92±0.61,following the order of winter>spring>summer>autumn.Sensitivity tests revealed that SO_(4)^(2−),NH_(x),T and RH triggered the variations of aerosol pH.Quantitative analysis results showed that T(37.9%-51.2%)was the main factors affecting pH variations in four seasons,followed by SO_(4)^(2−)(6.1%-23.7%),NH_(x)(7.2%-22.2%)and RH(0–14.2%).Totally,annual mean meteorological factors(52.9%)and chemical compositions(41.3%)commonly contributed the aerosolpH in the coastal city.The concentrations of PM_(2.5)was positively correlated with aerosol liquid water content(R^(2)=0.53)and aerosol pH(R^(2)=0.26),indicating that the increase in pH was related with the elevated NH_(4)NO_(3)and decreased SO_(4)^(2−),and also the changes of T and RH.The O_(x)(O_(3)+NO_(2))was moderately correlated with aerosol pH(R^(2)=-0.48),attributable to the fact that the proportion of SO_(4)^(2−)increased under high T and low RH conditions.The study strengthened our understanding of the contributions of influencing factors to aerosol pH,and also provided scientific evidences for chemical processes of atmospheric particles in coastal areas.展开更多
文摘This paper reports on the use of a kite-based system for measuring low-altitude particulate matter (PM) concentrations over grassland in Inner Mongolia. The motivation came from PM-concentration measurements at heights below 3 m over non-erodible surfaces which showed constant concentrations and made flux calculations relatively uncertain. One aim was the quantification of wind-driven matter fluxes across ecosystem boundaries, where the relevant layer can be assumed at heights below 100 m. Compared to other measurement techniques (e.g. LIDAR, towers and airborne systems) kite-based systems represent an inexpensive, highly flexible research tool which is well-suited for application in remote sites. The basis of the introduced system is a 4 m2 Parafoil kite which has enough lifting capacity to carry equipment of about 6 kg at wind velocities between 3 ms-1 to nearly 20 ms-1. A self-adjusting platform was constructed to balance moves and to carry a portable Environmental Dust Monitor (EDM), anemometer and a GPS receiver. So, all parameters necessary for a vertical profile of dust fluxes could be measured. In the first flights the applied kite-based dust profiling system (KIDS) was examined according to general technical application problems. Firstly, the influence of diverse surface characteristics, the flying condition and height-stability was tested. The result suggests that surface characteristics in general have a higher influence than the optimal wind velocity, which ranged from 9 ms-1 to 17 ms-1. Secondly, uncertainties in the measured data were quantified and assessed. The uncertainties in wind velocity measurements due to motion in horizontal and vertical direction were not higher than 0.45% - 0.65% and 1.8% - 2.2% during the kite ascent. The outcome of the study illustrates the suitable application of KIDS for low-altitude measurements in remote sites.
基金supported by the National Natural Science Foundation of China(Nos.42277091 and U22A20578)Xiamen Youth Innovation Fund Project(No.3502Z20206094)+1 种基金Fujian Provincial Environmental Protection Science&Technology Plan Projects(No.2023R004)Xiamen Atmospheric Environment Observation and Research Station of Fujian Province.
文摘Aerosol acidity(pH)plays an important role in the multiphase chemical processes of atmospheric particles.In this study,we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coastal city of southeast China.We performed quantitative analysis on the various influencing factors on aerosol pH,and explored the responses of aerosol pH to different PM_(2.5)and O_(3)pollution levels.The results showed that the average aerosol pH was 2.92±0.61,following the order of winter>spring>summer>autumn.Sensitivity tests revealed that SO_(4)^(2−),NH_(x),T and RH triggered the variations of aerosol pH.Quantitative analysis results showed that T(37.9%-51.2%)was the main factors affecting pH variations in four seasons,followed by SO_(4)^(2−)(6.1%-23.7%),NH_(x)(7.2%-22.2%)and RH(0–14.2%).Totally,annual mean meteorological factors(52.9%)and chemical compositions(41.3%)commonly contributed the aerosolpH in the coastal city.The concentrations of PM_(2.5)was positively correlated with aerosol liquid water content(R^(2)=0.53)and aerosol pH(R^(2)=0.26),indicating that the increase in pH was related with the elevated NH_(4)NO_(3)and decreased SO_(4)^(2−),and also the changes of T and RH.The O_(x)(O_(3)+NO_(2))was moderately correlated with aerosol pH(R^(2)=-0.48),attributable to the fact that the proportion of SO_(4)^(2−)increased under high T and low RH conditions.The study strengthened our understanding of the contributions of influencing factors to aerosol pH,and also provided scientific evidences for chemical processes of atmospheric particles in coastal areas.
