 |
| Titel |
UHF radar observation of strato-tropospheric transfers on the anticyclonic side of a jet streak |
| VerfasserIn |
F. Bertin, P. Velthoven, A. Cremieu, R. Ney, R. Beugin |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 13, no. 11 ; Nr. 13, no. 11, S.1229-1236 |
| Datensatznummer |
250012044
|
| Publikation (Nr.) |
 copernicus.org/angeo-13-1229-1995.pdf |
|
|
|
|
|
| Zusammenfassung |
| An observation by UHF ST radar of a
subsidence pattern on the right side of the exit region of a jet streak is
reported. The onset of the subsidence pattern occurred at 23:30 UTC on the 29
November 1991, when a downward motion was initiated above 14 km. The injections
of stratospheric air in this region seem to have an intermittent nature; they
occur during at least three intervals during the lifetime of the subsidence
pattern. Comparison of these results with an ECMWF analysis suggests that it is
an unfolding case. However, observation of turbulent intensities w'
greater than 60 cm s–1 at the tropopause level also suggests the
existence of a turbulent flux between the stratosphere and the troposphere. From
the turbulence characteristics measured by the radar and the potential
temperature profile obtained by radiosonde data, the eddy diffusivity at the
tropopause level has been calculated. An eddy diffusion coefficient ranging
between 5 and 7 m2 s–1 is found. From these values, and
with the assumption of a climatological gradient of the volume mixing ratio of
ozone in the lower stratosphere, it is possible to deduce a rough estimate of
the amount of ozone injected from the stratosphere into the troposphere during
this event. A rate of transfer of 1.5×1020 molecules of ozone per
day and per square meter is found. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|