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| Titel |
Effects of the horizontal propagation and refraction of gravity waves on elevated stratopause after sudden stratospheric warming |
| VerfasserIn |
In-Sun Song, Hwajin Choi, Changsup Lee, Jeong-Han Kim, Geonhwa Jee, Hyesun Choi, Baekmin Kim, Hyun-Joo Choi |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147694
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| Publikation (Nr.) |
 EGU/EGU2017-11895.pdf |
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| Zusammenfassung |
| Mesospheric temperature has been measured through the observation of airglow emissions
from OH Meinel bands near 87 km altitude using the Fourier Transform Spectrometers
(FTSs) operated at both Esrange (67∘53′N, 21∘04′E), Kiruna, Sweden and Korea Dasan
station (78∘55′N, 11∘56′E), Ny-Ålesund, Svalbard since November 2002. The FTS
observations have provided simultaneous records of time evolutions of air temperature at the
two different latitudes in association with elevated stratopause (ES) after major sudden
stratospheric warming (SSW) events. ES-like phenomena and relevant warming have been
simulated using global circulation models such as the whole-atmosphere community climate
model (WACCM), but the modeled warming is found to be much weaker compared with the
FTS observations (and satellite observations) especially in the higher latitudes (e.g., Dasan
station). Considering that gravity waves (GWs) may have substantial impacts in
the generation and evolution of the ES, the discrepancy between observation and
model may be attributed to common issues in GW parameterizations in the model
simulation: Uncertainty in GW spectra and unrealism in GW propagation (i.e., columnar
propagation). In this study, we investigate the effects of the horizontal propagation
and refraction of GWs on the warming associated with the ES after major SSW
events using a ray-tracing model with specified GW spectra. Preliminary results
for steady background flows show that the horizontal propagation and refraction
increase westward GW momentum forcing near z = 100 km in the NH high latitudes
that can induce downward motions and adiabatic warming in the NH polar regions
below z = 100 km. Results are extended for time-varying background flows and
different GW spectra to consider tidal effects and improve robustness of results,
respectively. |
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