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| Titel |
Refractivity and temperature climate records from multiple radio occultation satellites consistent within 0.05% |
| VerfasserIn |
U. Foelsche, B. Scherllin-Pirscher, F. Ladstädter, A. K. Steiner, G. Kirchengast |
| 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. 9 ; Nr. 4, no. 9 (2011-09-28), S.2007-2018 |
| Datensatznummer |
250002104
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| Publikation (Nr.) |
 copernicus.org/amt-4-2007-2011.pdf |
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| Zusammenfassung |
| Data consistency is an important prerequisite to build radio occultation
(RO) climatologies based on a combined record of data from different
satellites. The presence of multiple RO receiving satellites in orbit over
the same time period allows for testing this consistency. We used RO data
from CHAMP (CHAllenging Minisatellite Payload for geoscientific research),
six FORMOSAT-3/COSMIC satellites (Formosa Satellite Mission 3/Constellation
Observing System for Meteorology, Ionosphere and Climate, F3C), and GRACE-A
(Gravity Recovery and Climate Experiment). We show
latitude-altitude-resolved results for an example month (October 2007) and
the temporal evolution of differences in a climate record of global and
monthly means from January 2007 to December 2009. Latitude- and
altitude-resolved refractivity and dry temperature climatologies clearly
show the influence of different sampling characteristics; monthly mean
deviations from the multi-satellite mean over the altitude domain 10 km to
30 km typically reach 0.1% and 0.2 K, respectively. Nevertheless, the
3-yr average deviations (shorter for CHAMP) are less than 0.03% and
0.05 K, respectively. We find no indications for instrument degradation,
temporal inhomogeneities in the RO records, or temporal trends in sampling
patterns. Based on analysis fields from ECMWF (European Centre for
Medium-Range Weather Forecasts), we can estimate – and subtract – the
sampling error from each monthly climatology. After such subtraction,
refractivity deviations are found reduced to <0.05% in almost any
month and dry temperature deviations to <0.05 K (<0.02% relative)
for almost every satellite and month. 3-yr average deviations are even
reduced to <0.01% and <0.01 K (CHAMP: −0.05 K), respectively,
establishing an amazing consistency of RO climatologies from different
satellites. If applying the same processing scheme for all data,
refractivity and dry temperature records from individual satellites with
similar bending angle noise can be safely combined up to 30 km altitude
(refractivity also up to 35 km) to a consistent single climate record of
substantial value for climate monitoring in the upper troposphere and lower
stratosphere. |
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