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| Titel |
Accuracy of analyzed temperatures, winds and trajectories in the Southern Hemisphere tropical and midlatitude stratosphere as compared to long-duration balloon flights |
| VerfasserIn |
B. M. Knudsen, T. Christensen, A. Hertzog, A. Deme, F. Vial, J.-P. Pommereau |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 12 ; Nr. 6, no. 12 (2006-12-04), S.5391-5397 |
| Datensatznummer |
250004193
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| Publikation (Nr.) |
 copernicus.org/acp-6-5391-2006.pdf |
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| Zusammenfassung |
| Eight super-pressure balloons floating at constant level between 50 and 80 hPa
and three Infra-Red Montgolfier balloons of variable altitude (15 hPa
daytime, 40–80 hPa night time) have been launched at 22° S from Brazil
in February–May 2004 in the frame of the HIBISCUS project. The flights
lasted for 7 to 79 days residing mainly in the tropics, but some of them
passed the tropical barrier and went to southern midlatitudes. Compared to
the balloon measurements just above the tropical tropopause the ECMWF
operational temperatures show a systematic cold bias of 0.9 K and the
easterly zonal winds are too strong by 0.7 m/s. This bias in the zonal wind
adds to the ECMWF trajectory errors, but they still are relatively small
with e.g. about an error of 700 km after 5 days. The NCEP/NCAR reanalysis
trajectory errors are substantially larger (1300 km after 5 days). In the
southern midlatitudes the cold bias is the same, but the zonal wind bias is
almost zero. The trajectories are generally more accurate than in the
tropics, but for one balloon a lot of the calculated trajectories end up on
the wrong side of the tropical barrier and this leads to large trajectory
errors. |
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