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| Titel |
Comparison of ECMWF analyses with GPS radio occultations from CHAMP |
| VerfasserIn |
T. Schmidt, J. Wickert, S. Heise, F. Flechtner, E. Fagiolini, G. Schwarz, L. Zenner, T. Gruber |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 11 ; Nr. 26, no. 11 (2008-10-21), S.3225-3234 |
| Datensatznummer |
250016267
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| Publikation (Nr.) |
 copernicus.org/angeo-26-3225-2008.pdf |
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| Zusammenfassung |
| A climatological validation of the 6-hourly operational ECMWF
troposphere and lower stratosphere temperatures as well as
geopotential heights between 1000 and 10 hPa is performed using
the 2001–2007 (80 months from May 2001 to December 2007) CHAMP
radio occultation data. Generally there is a good agreement
between ECMWF and CHAMP temperatures averaged over 300–10 hPa for
all years/seasons with global annual mean biases (standard
deviations) less than 0.3 (1.7) K. Regional and temporal
discrepancies occur within the polar vortex mainly on the Southern
Hemisphere and the tropical tropopause region. Global annual mean
biases (standard deviations) of geopotential heights between 300
and 10 hPa are in the range of −30 up to +5 (30–50)
geopotential meter. Larger deviations from the mean values are
also observed in the tropics and polar zones. Both, the biases and
standard deviations between CHAMP and ECMWF temperatures and
geopotential heights differ significantly before and after
February and December 2006, i.e. the dates when ECMWF increased
the number of model levels from L60 to L91 (1 February 2006) and
where ECMWF became one of the first weather centers assimilating
radio occultation data (since 12 December 2006), mainly from the
COSMIC mission. At ECMWF the CHAMP data were only assimilated
until 4 February 2007, e.g. both data sets are mostly independent
from each other during the time period considered here. |
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