scholarly journals Evidence of a gravity wave breaking event and the estimation of the wave characteristics from sodium lidar observation over Fort Collins, CO (41°N, 105°W)

2007 ◽  
Vol 34 (5) ◽  
Author(s):  
Tao Li ◽  
C.-Y. She ◽  
Han-Li Liu ◽  
Michael T. Montgomery
Keyword(s):  
Gravity Wave ◽  
Wave Breaking ◽  
Lidar Observation ◽  
Wave Characteristics ◽  
Fort Collins

Lidar observation of gravity wave characteristics in the tropical middle atmosphere

2006 ◽  
Author(s):  
Maria Antonita T ◽  
Geetha Ramkumar ◽  
Bhavani Kumar ◽  
D. N. Rao
Keyword(s):  
Gravity Wave ◽  
Middle Atmosphere ◽  
Lidar Observation ◽  
Wave Characteristics

The Interaction of Katabatic Flow and Mountain Waves. Part II: Case Study Analysis and Conceptual Model

2007 ◽  
Vol 64 (6) ◽  
pp. 1857-1879 ◽  
Author(s):  
Gregory S. Poulos ◽  
James E. Bossert ◽  
Thomas B. McKee ◽  
Roger A. Pielke
Keyword(s):  
Conceptual Model ◽  
Gravity Wave ◽  
Wave Breaking ◽  
Gradient Force ◽  
Pressure Gradient Force ◽  
Wave System ◽  
Katabatic Flow ◽  
Mountain Wave ◽  
Mountain Waves ◽  
Wave Evolution

Via numerical analysis of detailed simulations of an early September 1993 case night, the authors develop a conceptual model of the interaction of katabatic flow in the nocturnal boundary layer with mountain waves (MKI). A companion paper (Part I) describes the synoptic and mesoscale observations of the case night from the Atmospheric Studies in Complex Terrain (ASCOT) experiment and idealized numerical simulations that manifest components of the conceptual model of MKI presented herein. The reader is also referred to Part I for detailed scientific background and motivation. The interaction of these phenomena is complicated and nonlinear since the amplitude, wavelength, and vertical structure of the mountain-wave system developed by flow over the barrier owes some portion of its morphology to the evolving atmospheric stability in which the drainage flows develop. Simultaneously, katabatic flows are impacted by the topographically induced gravity wave evolution, which may include significantly changing wavelength, amplitude, flow magnitude, and wave breaking behavior. In addition to effects caused by turbulence (including scouring), perturbations to the leeside gravity wave structure at altitudes physically distant from the surface-based katabatic flow layer can be reflected in the katabatic flow by transmission through the atmospheric column. The simulations show that the evolution of atmospheric structure aloft can create local variability in the surface pressure gradient force governing katabatic flow. Variability is found to occur on two scales, on the meso-β due to evolution of the mountain-wave system on the order of one hour, and on the microscale due to rapid wave evolution (short wavelength) and wave breaking–induced fluctuations. It is proposed that the MKI mechanism explains a portion of the variability in observational records of katabatic flow.

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 An Intercomparison of T-REX Mountain-Wave Simulations and Implications for Mesoscale Predictability

2011 ◽  
Vol 139 (9) ◽  
pp. 2811-2831 ◽  
Author(s):  
James D. Doyle ◽  
Saša Gaberšek ◽  
Qingfang Jiang ◽  
Ligia Bernardet ◽  
John M. Brown ◽  
...  
Keyword(s):  
Wave Breaking ◽  
Numerical Models ◽  
Lower Boundary ◽  
Horizontal Resolution ◽  
Test Cases ◽  
Mountain Wave ◽  
Initial State ◽  
Wave Characteristics ◽  
Rotor Experiment ◽  
Ensemble Systems

Numerical simulations of flow over steep terrain using 11 different nonhydrostatic numerical models are compared and analyzed. A basic benchmark and five other test cases are simulated in a two-dimensional framework using the same initial state, which is based on conditions during Intensive Observation Period (IOP) 6 of the Terrain-Induced Rotor Experiment (T-REX), in which intense mountain-wave activity was observed. All of the models use an identical horizontal resolution of 1 km and the same vertical resolution. The six simulated test cases use various terrain heights: a 100-m bell-shaped hill, a 1000-m idealized ridge that is steeper on the lee slope, a 2500-m ridge with the same terrain shape, and a cross-Sierra terrain profile. The models are tested with both free-slip and no-slip lower boundary conditions. The results indicate a surprisingly diverse spectrum of simulated mountain-wave characteristics including lee waves, hydraulic-like jump features, and gravity wave breaking. The vertical velocity standard deviation is twice as large in the free-slip experiments relative to the no-slip simulations. Nevertheless, the no-slip simulations also exhibit considerable variations in the wave characteristics. The results imply relatively low predictability of key characteristics of topographically forced flows such as the strength of downslope winds and stratospheric wave breaking. The vertical flux of horizontal momentum, which is a domain-integrated quantity, exhibits considerable spread among the models, particularly for the experiments with the 2500-m ridge and Sierra terrain. The differences among the various model simulations, all initialized with identical initial states, suggest that model dynamical cores may be an important component of diversity for the design of mesoscale ensemble systems for topographically forced flows. The intermodel differences are significantly larger than sensitivity experiments within a single modeling system.

scholarly journals Local mean state changes due to gravity wave breaking modulated by the diurnal tide

2000 ◽  
Vol 105 (D10) ◽  
pp. 12381-12396 ◽  
Author(s):  
Han-Li Liu ◽  
Maura E. Hagan ◽  
Raymond G. Roble
Keyword(s):  
Gravity Wave ◽  
Wave Breaking ◽  
Diurnal Tide ◽  
Local Mean ◽  
State Changes ◽  
Mean State
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