Frequency variations of gravity waves interacting with a time-varying tide
Item
Title (Dublin Core)
Frequency variations of gravity waves interacting with a time-varying tide
Description (Dublin Core)
Using a nonlinear, 2-D time-dependent numerical model, we simulate the
propagation of gravity waves (GWs) in a time-varying tide. Our simulations
show that when a GW packet propagates in a time-varying tidal-wind
environment, not only its intrinsic frequency but also its ground-based
frequency would change significantly. The tidal horizontal-wind acceleration
dominates the GW frequency variation. Positive (negative) accelerations
induce frequency increases (decreases) with time. More interestingly,
tidal-wind acceleration near the critical layers always causes the GW
frequency to increase, which may partially explain the observations that
high-frequency GW components are more dominant in the middle and upper
atmosphere than in the lower atmosphere. The combination of the increased
ground-based frequency of propagating GWs in a time-varying tidal-wind field
and the transient nature of the critical layer induced by a time-varying
tidal zonal wind creates favorable conditions for GWs to penetrate their
originally expected critical layers. Consequently, GWs have an impact on the
background atmosphere at much higher altitudes than expected, which indicates
that the dynamical effects of tidal–GW interactions are more complicated
than usually taken into account by GW parameterizations in global models.
propagation of gravity waves (GWs) in a time-varying tide. Our simulations
show that when a GW packet propagates in a time-varying tidal-wind
environment, not only its intrinsic frequency but also its ground-based
frequency would change significantly. The tidal horizontal-wind acceleration
dominates the GW frequency variation. Positive (negative) accelerations
induce frequency increases (decreases) with time. More interestingly,
tidal-wind acceleration near the critical layers always causes the GW
frequency to increase, which may partially explain the observations that
high-frequency GW components are more dominant in the middle and upper
atmosphere than in the lower atmosphere. The combination of the increased
ground-based frequency of propagating GWs in a time-varying tidal-wind field
and the transient nature of the critical layer induced by a time-varying
tidal zonal wind creates favorable conditions for GWs to penetrate their
originally expected critical layers. Consequently, GWs have an impact on the
background atmosphere at much higher altitudes than expected, which indicates
that the dynamical effects of tidal–GW interactions are more complicated
than usually taken into account by GW parameterizations in global models.
Creator (Dublin Core)
C. M. Huang
S. D. Zhang
F. Yi
K. M. Huang
Y. H. Zhang
Q. Gan
Y. Gong
Subject (Dublin Core)
Science
Q
Physics
QC1-999
Geophysics. Cosmic physics
QC801-809
Publisher (Dublin Core)
Copernicus Publications
Date (Dublin Core)
2013-10-01T00:00:00Z
Type (Dublin Core)
article
Identifier (Dublin Core)
10.5194/angeo-31-1731-2013
0992-7689
1432-0576
https://doaj.org/article/2ee976c342144ce89ce3544d9233ec52
Source (Dublin Core)
Annales Geophysicae, Vol 31, Pp 1731-1743 (2013)
Language (Dublin Core)
EN
Relation (Dublin Core)
https://www.ann-geophys.net/31/1731/2013/angeo-31-1731-2013.pdf
https://doaj.org/toc/0992-7689
https://doaj.org/toc/1432-0576
Provenance (Dublin Core)
Journal Licence: CC BY