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| Titel |
Tropospheric aerosol profile information from high-resolution oxygen A-band measurements from space |
| VerfasserIn |
A. Geddes, H. Bösch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 2 ; Nr. 8, no. 2 (2015-02-20), S.859-874 |
| Datensatznummer |
250116140
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| Publikation (Nr.) |
 copernicus.org/amt-8-859-2015.pdf |
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| Zusammenfassung |
| Aerosols are an important factor in the Earth climatic system and they play a
key role in air quality and public health. Observations of the oxygen A-band
at 760 nm can provide information on the vertical distribution of aerosols
from passive satellite sensors that can be of great interest for operational
monitoring applications with high spatial coverage if the aerosol information
is obtained with sufficient precision, accuracy and vertical resolution. To
address this issue, retrieval simulations of the aerosol vertical profile
retrieval from O2 A-band observations by GOSAT, the upcoming Orbiting Carbon Observatory-2 (OCO-2) and
Sentinel 5-P missions, and the proposed CarbonSat mission have been carried
out. Precise retrievals of aerosol optical depth (AOD) within the boundary layer were found to favour
low-resolution, high signal-to-noise instruments such as Sentinel-5 P, whereas higher-resolution instruments such as OCO-2 showed greater performance at higher
altitudes and in information content above the boundary layer. Retrieval of
the AOD in the 0–2 km range with precision appears difficult from all
studied instruments and the retrieval errors typically exceed a value of 0.05
for AODs up to 0.3. Constraining the surface albedo is a promising and
effective way of improving the retrieval of aerosol, but the accuracy of the
required prior knowledge is very high. Due to the limited information content
of the aerosol profile retrieval, the use of a parameterised aerosol
distribution is assessed, and we show that the AOD and height of an
aerosol layer can be retrieved well if the aerosol layer is uplifted to the
free troposphere; however, errors are often large for aerosol layers in the
boundary layer. Additional errors are introduced by incorrect assumptions
on surface pressure and aerosol mixture, which can both bias retrieved AOD and
height by up to 45%. In addition, assumptions of the boundary layer
temperature are found to yield an additional error of up to 8%. We
conclude that the aerosol profile retrievals from O2 A-band using existing or
upcoming satellite sensors will only provide limited information on aerosols
in the boundary layer but such observations can be of great value for
observing and mapping aerosol plumes in the free troposphere. |
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