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| Titel |
Generation of a bending angle radio occultation climatology (BAROCLIM) and its use in radio occultation retrievals |
| VerfasserIn |
B. Scherllin-Pirscher, S. Syndergaard, U. Foelsche, K. B. Lauritsen |
| 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. 1 ; Nr. 8, no. 1 (2015-01-09), S.109-124 |
| Datensatznummer |
250116042
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| Publikation (Nr.) |
 copernicus.org/amt-8-109-2015.pdf |
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| Zusammenfassung |
| In this paper, we introduce a bending angle radio occultation
climatology (BAROCLIM) based on Formosat-3/COSMIC (F3C)
data. This climatology represents the monthly-mean atmospheric state
from 2006 to 2012. Bending angles from radio occultation (RO)
measurements are obtained from the accumulation of the change in the
raypath direction of Global Positioning System (GPS) signals. Best
quality of these near-vertical profiles is found from the middle
troposphere up to the mesosphere. Beside RO bending angles we also
use data from the Mass Spectrometer and Incoherent Scatter Radar
(MSIS) model (modified for RO purposes) to expand BAROCLIM in a spectral model, which
(theoretically) reaches from the surface up to infinity. Due to the
very high quality of BAROCLIM up to the mesosphere, it can be used
to detect deficiencies in current state-of-the-art analysis and
reanalysis products from numerical weather prediction (NWP) centers.
For bending angles derived from European Centre for Medium-Range
Weather Forecasts (ECMWF) analysis fields from 2006 to 2012, e.g.,
we find a positive bias of 0.5 to 1% at
40 km, which increases to more than 2% at
50 km. BAROCLIM can also be used as a priori information in
RO profile retrievals. In contrast to other a priori information
(i.e., MSIS) we find that the use of BAROCLIM better preserves the
mean of raw RO measurements. Global statistics of statistically
optimized bending angle and refractivity profiles also confirm that
BAROCLIM outperforms MSIS. These results clearly demonstrate the
utility of BAROCLIM. |
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