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| Titel |
A 3-D tomographic retrieval approach with advection compensation for the air-borne limb-imager GLORIA |
| VerfasserIn |
J. Ungermann, J. Blank, J. Lotz, K. Leppkes, L. Hoffmann, T. Guggenmoser, M. Kaufmann, P. Preusse, U. Naumann, M. Riese |
| 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 ; 4, no. 11 ; Nr. 4, no. 11 (2011-11-24), S.2509-2529 |
| Datensatznummer |
250002138
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| Publikation (Nr.) |
 copernicus.org/amt-4-2509-2011.pdf |
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| Zusammenfassung |
Infrared limb sounding from aircraft can provide 2-D curtains
of multiple trace gas species. However, conventional limb sounders
view perpendicular to the aircraft axis and are unable to resolve the
observed airmass along their line-of-sight. GLORIA (Gimballed Limb
Observer for Radiance Imaging of the Atmosphere) is a new remote
sensing instrument that is able to adjust its horizontal view angle with
respect to the aircraft flight direction from 45° to
135°. This will allow for tomographic measurements of
mesoscale structures for a wide variety of atmospheric constituents.
Many flights of the GLORIA instrument will not follow closed curves that
allow measuring an airmass from all directions. Consequently, it is
examined by means of simulations, what spatial resolution can be expected
under ideal conditions from tomographic evaluation of measurements made
during a straight flight. It is demonstrated that the achievable
horizontal resolution in the line-of-sight direction could be reduced from
over 200 km to around 70 km compared to conventional retrievals and that
the tomographic retrieval is also more robust against horizontal gradients
in retrieved quantities in this direction. In a second step, it is shown
that the incorporation of channels exhibiting different optical depth can
further enhance the spatial resolution of 3-D retrievals enabling the
exploitation of spectral samples usually not used for limb sounding due to
their opacity.
A second problem for tomographic retrievals is that advection, which
can be neglected for conventional retrievals, plays an important role
for the time-scales involved in a tomographic measurement flight. This
paper presents a method to diagnose the effect of a time-varying
atmosphere on a 3-D retrieval and demonstrates an effective way
to compensate for effects of advection by incorporating wind-fields
from meteorological datasets as a priori information. |
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