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| Titel |
Tracking of Urban Aerosols Using a Scanning Mie Lidar |
| VerfasserIn |
Tingyao He, Fei Gao, Samo Stanič, Klemen Bergant, Darko Veberič, Xiaoquan Song, Aleš Dolžan |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055502
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| Zusammenfassung |
| Increase of aerosol concentration in urban areas caused by human activities has a significant
impact on the status of the environment and quality of life in general. In the cities the
presence of aerosols can cause reduced visibility and increase the rates of the atmospheric
opto-chemical reactions. Scanning aerosol lidars offer the ability to monitor air
pollution, plume dispersion, visibility and to track plumes of potentially hazardous
aerosols.
A preliminary study of aerosol monitoring in urban areas was performed over the
neighbouring towns of Nova Gorica in Slovenia and Gorizia in Italy using a scanning Mie
lidar operating in infrared range (1064nm). The lidar system was developed within our
laboratory and can perform hemispherical scans of the atmosphere with high spatial
resolution (3.75m). A measuring campaign was done on 24 and 25 May 2010 from
8AM to 7PM to investigate the two-dimensional spatial and temporal distribution
of urban aerosols. Two different scanning paterns were used. In a Range Height
Indicator (RHI) scan, the elevation angle was increased in 1° steps covering a range of
45° from the horizontal while keeping the azimuth angle constant, and in Plane
Position Indicator (PPI) scan, where the elevation angle was set to zero, the azimuth
angle was changed in 2° steps covering a range of 62°. Each scan took 8 minutes to
complete.
As a result of the study we estimated the detectable lidar range for the device and
obtained two-dimensional distributions of increased aerosol loading, which can be used to
investigate flow dynamics and locate aerosol sources. We obtained the temporal variation of
the spatially averaged aerosol concentration throughout the day. Its most prominent feature
was a local peak in aerosol concentration which appeared around noon. The concentration
briefly decreased in the early afternoon and increased again to reach its daily peak around
5PM. Based on the aerosol extinction coefficients retrieved by analytical inversion of lidar
return signal (Klett method), we found that the atmosphere was not horizontaly
homogeneous. Noticeable spatially localized temporal variations of the lidar return signal
were also observed, such as the presence of point sources of particulate matter at a
horizontal distance of about 2km from the lidar site which was later confirmed in the
field.
As the tracking of aerosol features allows us to identify aerosol sources and thus control
the emission of pollutants, our future plans are to establish an automated environmental
monitoring system that provide spatial distribution of aerosol loading in various
environmental settings and to develop data analysis software capable of animated temporal
presentations of the plume trajectories. |
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