scholarly journals A model study of the effects of winds on concentric rings of gravity waves from a convective plume near Fort Collins on 11 May 2004

2009 ◽  
Vol 114 (D6) ◽  
Author(s):  
Sharon L. Vadas ◽  
Jia Yue ◽  
Chiao-Yao She ◽  
Peter A. Stamus ◽  
Alan Z. Liu
Keyword(s):  
Gravity Waves ◽  
Model Study ◽  
Fort Collins ◽  
Convective Plume

scholarly journals Convection: the likely source of the medium-scale gravity waves observed in the OH airglow layer near Brasilia, Brazil, during the SpreadFEx campaign

2009 ◽  
Vol 27 (1) ◽  
pp. 231-259 ◽  
Author(s):  
S. L. Vadas ◽  
M. J. Taylor ◽  
P.-D. Pautet ◽  
P. A. Stamus ◽  
D. C. Fritts ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Deep Convection ◽  
The Other ◽  
Medium Scale ◽  
Trace Model ◽  
Spread F ◽  
Convection Model ◽  
Ray Trace ◽  
Convective Plume ◽  
Vertical Scales

Abstract. Six medium-scale gravity waves (GWs) with horizontal wavelengths of λH=60–160 km were detected on four nights by Taylor et al. (2009) in the OH airglow layer near Brasilia, at 15° S, 47° W, during the Spread F Experiment (SpreadFEx) in Brazil in 2005. We reverse and forward ray trace these GWs to the tropopause and into the thermosphere using a ray trace model which includes thermospheric dissipation. We identify the convective plumes, convective clusters, and convective regions which may have generated these GWs. We find that deep convection is the highly likely source of four of these GWs. We pinpoint the specific deep convective plumes which likely excited two of these GWs on the nights of 30 September and 1 October. On these nights, the source location/time uncertainties were small and deep convection was sporadic near the modeled source locations. We locate the regions containing deep convective plumes and clusters which likely excited the other two GWs. The last 2 GWs were probably also excited from deep convection; however, they must have been ducted ~500–700 km if so. Two of the GWs were likely downwards-propagating initially (after which they reflected upwards from the Earth's surface), while one of the GWs was likely upwards-propagating initially from the convective plume/cluster. We also estimate the amplitudes and vertical scales of these waves at the tropopause, and compare their scales with those from a simple, linear convection model. Finally, we calculate each GW's dissipation altitude, location, and amplitude. We find that the dissipation altitude depends sensitively on the winds at and above the OH layer. We also find that several of these GWs may have penetrated to high enough altitudes to potentially seed equatorial spread F (ESF) if located somewhat farther from the magnetic equator.

scholarly journals HURRICANE STORM SURGE CONSIDERED AS A RESONANCE PHENOMENON

2011 ◽  
Vol 1 (7) ◽  
pp. 31 ◽  
Author(s):  
G. Abraham
Keyword(s):  
Gravity Waves ◽  
Constant Velocity ◽  
Resonance Phenomenon ◽  
Critical Conditions ◽  
Constant Depth ◽  
Local Disturbance ◽  
Maximum Value ◽  
Model Study ◽  
Wave Heights ◽  
Hurricane Storm Surge

A model study was performed to study the water gravity waves generated by a circular local disturbance of pressure, advancing with constant velocity over the surface of water of constant depth. The results indicate that under critical conditions a resonance type phenomenon occurs for which the associated wave heights have a maximum value. It is shown that the resonant conditions may be an important factor for the generation of the surge due to hurricanes, that approach the coast perpendicularly.

scholarly journals Concentric gravity waves in the mesosphere generated by deep convective plumes in the lower atmosphere near Fort Collins, Colorado

2009 ◽  
Vol 114 (D6) ◽  
Author(s):  
Jia Yue ◽  
Sharon L. Vadas ◽  
Chiao-Yao She ◽  
Takuji Nakamura ◽  
Steven C. Reising ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Lower Atmosphere ◽  
Fort Collins

Model Study of Waves Generated by Convection with Direct Validation via Satellite

2010 ◽  
Vol 67 (5) ◽  
pp. 1617-1631 ◽  
Author(s):  
Alison W. Grimsdell ◽  
M. Joan Alexander ◽  
Peter T. May ◽  
Lars Hoffmann
Keyword(s):  
Gravity Waves ◽  
Three Dimensional ◽  
Early Morning ◽  
Wave Pattern ◽  
Global Scale ◽  
Major Effect ◽  
Small Scale ◽  
Model Studies ◽  
Model Study ◽  
Cloud Resolving Model

Abstract Atmospheric gravity waves have a major effect on atmospheric circulation, structure, and stability on a global scale. Gravity waves can be generated by convection, but in many cases it is difficult to link convection directly to a specific wave event. In this research, the authors examine an event on 12 January 2003 when convective waves were clearly generated by a period of extremely intense rainfall in the region of Darwin, Australia, during the early morning. The waves were observed by the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite, and a dry version of a nonlinear, three-dimensional mesoscale cloud-resolving model is used to generate a comparable wave field. The model is forced by a spatially and temporally varying heating field obtained from a scanning radar located north of Darwin at Gunn Point. With typical cloud-resolving model studies it is generally not possible to compare the model results feature-for-feature with observations since although the model precipitation and small-scale heating may be similar to observations, they will occur at different locations and times. In this case the comparison is possible since the model is forced by the observed heating pattern. It is shown that the model output wave pattern corresponds well to the wave pattern observed by the AIRS instrument at the time of the AIRS overpass.

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