 |
| Titel |
Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008) |
| VerfasserIn |
F. Chane Ming, C. Ibrahim, C. Barthe, S. Jolivet, P. Keckhut, Y.-A. Liou, Y. Kuleshov |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 2 ; Nr. 14, no. 2 (2014-01-22), S.641-658 |
| Datensatznummer |
250118297
|
| Publikation (Nr.) |
 copernicus.org/acp-14-641-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Gravity waves (GWs) with horizontal wavelengths of 32–2000 km are
investigated during tropical cyclone (TC) Ivan (2008) in the southwest Indian
Ocean in the upper troposphere (UT) and the lower stratosphere (LS) using
observational data sets, radiosonde and GPS radio occultation data, ECMWF
analyses and simulations of the French numerical model Meso-NH with vertical
resolution < 150 m near the surface and 500 m in the UT/LS. Observations
reveal dominant low-frequency GWs with short vertical wavelengths of
0.7–3 km, horizontal wavelengths of 80–400 km and periods of 4.6–13 h
in the UT/LS. Continuous wavelet transform and image-processing tools
highlight a wide spectrum of GWs with horizontal wavelengths of 40–1800 km,
short vertical wavelengths of 0.6–3.3 km and periods of 20 min–2 days
from modelling analyses. Both ECMWF and Meso-NH analyses are consistent with
radiosonde and GPS radio occultation data, showing evidence of a dominant
TC-related quasi-inertia GW propagating eastward east of TC Ivan with
horizontal and vertical wavelengths of 400–800 km and 2–3 km respectively
in the LS, more intense during TC intensification. In addition, the Meso-NH
model produces a realistic, detailed description of TC dynamics, some
high-frequency GWs near the TC eye, variability of the tropospheric and
stratospheric background wind and TC rainband characteristics at different
stages of TC Ivan. A wave number 1 vortex Rossby wave is suggested as a
source of dominant inertia GW with horizontal wavelengths of 400–800 km,
while shorter scale modes (100–200 km) located at northeast and southeast
of the TC could be attributed to strong localized convection in spiral bands
resulting from wave number 2 vortex Rossby waves. Meso-NH simulations also
reveal GW-related clouds east of TC Ivan. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|