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| Titel |
Characteristics of gravity waves revealed in a high-resolution baroclinic wave simulation |
| VerfasserIn |
Young-Ha Kim, Hye-Yeong Chun, Sang-Hun Park, Hyun-Joo Choi, In-Sun Song |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250108649
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| Publikation (Nr.) |
 EGU/EGU2015-8412.pdf |
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| Zusammenfassung |
| Mesoscale modeling results from an idealized baroclinic wave simulation are used to
investigate gravity waves associated with jet and frontal systems. The simulation is conducted
using the global Weather Research and Forecasting (WRF) model with a horizontal resolution
of ~0.09°, based on the balanced initial conditions proposed by Jablonowski and Williamson
and a baroclinic wave disturbance with a zonal wavenumber 9. In the simulation, the
mesoscale gravity waves begin to appear around 55°N when and where the baroclinic wave
disturbance is well developed. These gravity waves (G1) are identified by three wave packets
in the upper troposphere propagating eastward, southeastward, and northeastward, which are
advected by the background westerly jet. They have horizontal wavelengths of 50–600
km at 300ÂhPa, with a peak of approximately 110 km. Their phase speed ranges
from 10 to 23Âm s-1. About one day after the G1 appears, a secondary cyclone is
developed in the lower troposphere around 45°N according to the development of
baroclinic waves, and mesoscale gravity waves distinct from G1 appear (G2) above this
cyclone. The G2 is quasi-stationary, with a peak wavelength of about 360 km at
300ÂhPa. For both G1 and G2, the zonal momentum flux is negative, implying that
upward-propagating mode is dominant. In the lower stratosphere, the magnitude of G1
decreases significantly because the waves are largely filtered above the jet, whereas the
quasi-stationary G2 propagates into the stratosphere with substantial amplitudes. |
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