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| Titel |
Transport of Antarctic stratospheric strongly dehydrated air into the troposphere observed during the HALO-ESMVal campaign 2012 |
| VerfasserIn |
C. Rolf, A. Afchine, H. Bozem, B. Buchholz, V. Ebert, T. Guggenmoser, P. Hoor, P. Konopka, E. Kretschmer, S. Müller, H. Schlager, N. Spelten, O. Sumińska-Ebersoldt, J. Ungermann, A. Zahn, M. Krämer |
| 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 ; 15, no. 16 ; Nr. 15, no. 16 (2015-08-18), S.9143-9158 |
| Datensatznummer |
250119972
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| Publikation (Nr.) |
 copernicus.org/acp-15-9143-2015.pdf |
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| Zusammenfassung |
| Dehydration in the Antarctic winter stratosphere is a well-known phenomenon
that is annually observed by satellites and occasionally observed by
balloon-borne measurements. However, in situ measurements of dehydrated air
masses in the Antarctic vortex are very rare. Here, we present detailed
observations with the in situ and GLORIA remote sensing instrument payload
aboard the German aircraft HALO. Strongly dehydrated air masses down to
1.6 ppmv of water vapor were observed as far north as 47° S in
an altitude between 12 and 13 km in the lowermost stratosphere. The
dehydration can be traced back to individual ice formation events above the
Antarctic Peninsula and Plateau, where ice crystals sedimented out and water
vapor was irreversibly removed. Within these dehydrated stratospheric air
masses, filaments of moister air reaching down to the tropopause are detected
with the high-resolution limb sounder, GLORIA. Furthermore, dehydrated air
masses are observed with GLORIA in the Antarctic lowermost stratosphere down
to 7 km. With the help of a backward trajectory analysis, a midlatitude
origin of the moist filaments in the vortex can be identified, while the dry
air masses down to 7 km have stratospheric origins. Antarctic
stratosphere–troposphere exchange (STE) and transport of dehydrated air
masses into the troposphere are investigated. Further, it is shown that the
exchange process can be attributed to several successive Rossby wave events
in combination with an isentropic exchange of air masses across the thermal
tropopause. The transport into the troposphere is caused by air masses that
are detached from the potential vorticity (PV) structure by Rossby wave breaking events and
subsequently transported diabatically across the dynamical tropopause. Once
transported to the troposphere, air masses with stratospheric origin can
reach near-surface levels within several days. |
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