scholarly journals Gravity wave characteristics in the lower atmosphere at south pole

1999 ◽  
Vol 104 (D6) ◽  
pp. 5963-5984 ◽  
Author(s):  
Matt Pfenninger ◽  
Alan Z. Liu ◽  
George C. Papen ◽  
Chester S. Gardner
Keyword(s):  
Gravity Wave ◽  
Lower Atmosphere ◽  
South Pole ◽  
Wave Characteristics

Stratospheric gravity wave characteristics and seasonal variations observed by lidar at the South Pole and Rothera, Antarctica

2009 ◽  
Vol 114 (D12) ◽  
Author(s):  
Chihoko Yamashita ◽  
Xinzhao Chu ◽  
Han-Li Liu ◽  
Patrick J. Espy ◽  
Graeme J. Nott ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Seasonal Variations ◽  
South Pole ◽  
The South ◽  
Wave Characteristics

scholarly journals Enhanced gravity-wave activity and interhemispheric coupling during the MaCWAVE/MIDAS northern summer program 2002

2006 ◽  
Vol 24 (4) ◽  
pp. 1175-1188 ◽  
Author(s):  
E. Becker ◽  
D. C. Fritts
Keyword(s):  
Gravity Wave ◽  
Rossby Wave ◽  
Lower Thermosphere ◽  
Wave Activity ◽  
Lower Atmosphere ◽  
Summer Program ◽  
Latent Heating ◽  
Austral Winter ◽  
Northern Summer ◽  
Mesosphere And Lower Thermosphere

Abstract. We present new sensitivity experiments that link observed anomalies of the mesosphere and lower thermosphere at high latitudes during the MaCWAVE/MIDAS summer program 2002 to enhanced planetary Rossby-wave activity in the austral winter troposphere. We employ the same general concept of a GCM having simplified representations of radiative and latent heating as in a previous study by Becker et al. (2004). In the present version, however, the model includes no gravity wave (GW) parameterization. Instead we employ a high vertical and a moderate horizontal resolution in order to describe GW effects explicitly. This is supported by advanced, nonlinear momentum diffusion schemes that allow for a self-consistent generation of inertia and mid-frequency GWs in the lower atmosphere, their vertical propagation into the mesosphere and lower thermosphere, and their subsequent dissipation which is induced by prescribed horizontal and vertical mixing lengths as functions of height. The main anomalies in northern summer 2002 consist of higher temperatures than usual above 82 km, an anomalous eastward mean zonal wind between 70 and 90 km, an altered meridional flow, enhanced turbulent dissipation below 80 km, and enhanced temperature variations associated with GWs. These signals are all reasonably described by differences between two long-integration perpetual model runs, one with normal July conditions, and another run with modified latent heating in the tropics and Southern Hemisphere to mimic conditions that correspond to the unusual austral winter 2002. The model response to the enhanced winter hemisphere Rossby-wave activity has resulted in both an interhemispheric coupling through a downward shift of the GW-driven branch of the residual circulation and an increased GW activity at high summer latitudes. Thus a quantitative explanation of the dynamical state of the northern mesosphere and lower thermosphere during June-August 2002 requires an enhanced Lorenz energy cycle and correspondingly enhanced GW sources in the troposphere, which in the model show up in both hemispheres.

scholarly journals Gravity Wave Characteristics over the Equator Observed During the CPEA Campaign using Simultaneous Data from Multiple Stations

2006 ◽  
Vol 84A ◽  
pp. 239-257 ◽  
Author(s):  
M. VENKAT RATNAM ◽  
Toshitaka TSUDA ◽  
Yoshiaki SHIBAGAKI ◽  
Toshiaki KOZU ◽  
Shuichi MORI
Keyword(s):  
Gravity Wave ◽  
Wave Characteristics

scholarly journals Variability of Gravity Wave Effects on the Zonal Mean Circulation and Migrating Terdiurnal Tide as Studied With the Middle and Upper Atmosphere Model (MUAM2019) Using a Nonlinear Gravity Wave Scheme

2020 ◽  
Vol 7 ◽  
Author(s):  
Friederike Lilienthal ◽  
Erdal Yiğit ◽  
Nadja Samtleben ◽  
Christoph Jacobi
Keyword(s):  
Gravity Wave ◽  
Strong Dependence ◽  
Lower Thermosphere ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Small Scale ◽  
Source Level ◽  
Atmosphere Model ◽  
Hemisphere Winter ◽  
Nonlinear Gravity

Implementing a nonlinear gravity wave (GW) parameterization into a mechanistic middle and upper atmosphere model, which extends to the lower thermosphere (160 km), we study the response of the atmosphere in terms of the circulation patterns, temperature distribution, and migrating terdiurnal solar tide activity to the upward propagating small-scale internal GWs originating in the lower atmosphere. We perform three test simulations for the Northern Hemisphere winter conditions in order to assess the effects of variations in the initial GW spectrum on the climatology and tidal patterns of the mesosphere and lower thermosphere. We find that the overall strength of the source level momentum flux has a relatively small impact on the zonal mean climatology. The tails of the GW source level spectrum, however, are crucial for the lower thermosphere climatology. With respect to the terdiurnal tide, we find a strong dependence of tidal amplitude on the induced GW drag, generally being larger when GW drag is increased.

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