Generation of Inertia–Gravity Waves in a Simulated Life Cycle of Baroclinic Instability

1995 ◽  
Vol 52 (21) ◽  
pp. 3695-3716 ◽  
Author(s):  
Donal O'sullivan ◽  
Timothy J. Dunkerton
Keyword(s):  
Life Cycle ◽  
Gravity Waves ◽  
Baroclinic Instability ◽  
Inertia Gravity Waves

Inertia–Gravity Waves Spontaneously Generated by Jets and Fronts. Part I: Different Baroclinic Life Cycles

2007 ◽  
Vol 64 (7) ◽  
pp. 2502-2520 ◽  
Author(s):  
Riwal Plougonven ◽  
Chris Snyder
Keyword(s):  
Life Cycle ◽  
Gravity Waves ◽  
Lower Stratosphere ◽  
Baroclinic Instability ◽  
Life Cycles ◽  
Weather Research And Forecasting ◽  
Spontaneous Generation ◽  
Upper Level ◽  
Upper Level Jet ◽  
Inertia Gravity Waves

Abstract The spontaneous generation of inertia–gravity waves in idealized life cycles of baroclinic instability is investigated using the Weather Research and Forecasting Model. Two substantially different life cycles of baroclinic instability are obtained by varying the initial zonal jet. The wave generation depends strongly on the details of the baroclinic wave’s development. In the life cycle dominated by cyclonic behavior, the most conspicuous gravity waves are excited by the upper-level jet and are broadly consistent with previous simulations of O’Sullivan and Dunkerton. In the life cycle that is dominated by anticyclonic behavior, the most conspicuous gravity waves even in the stratosphere are excited by the surface fronts, although the fronts are no stronger than in the cyclonic life cycle. The anticyclonic life cycle also reveals waves in the lower stratosphere above the upper-level trough of the baroclinic wave; these waves have not been previously identified in idealized simulations. The sensitivities of the different waves to both resolution and dissipation are discussed.

scholarly journals The Mesoscale Kinetic Energy Spectrum of a Baroclinic Life Cycle

2009 ◽  
Vol 66 (4) ◽  
pp. 883-901 ◽  
Author(s):  
Michael L. Waite ◽  
Chris Snyder
Keyword(s):  
Life Cycle ◽  
Energy Spectrum ◽  
Kinetic Energy ◽  
Gravity Waves ◽  
Linear Instability ◽  
Mature Stage ◽  
Flux Divergence ◽  
Full Spectrum ◽  
Kinetic Energy Spectrum ◽  
Inertia Gravity Waves

Abstract The atmospheric mesoscale kinetic energy spectrum is investigated through numerical simulations of an idealized baroclinic wave life cycle, from linear instability to mature nonlinear evolution and with high horizontal and vertical resolution (Δx ≈ 10 km and Δz ≈ 60 m). The spontaneous excitation of inertia–gravity waves yields a shallowing of the mesoscale spectrum with respect to the large scales, in qualitative agreement with observations. However, this shallowing is restricted to the lower stratosphere and does not occur in the upper troposphere. At both levels, the mesoscale divergent kinetic energy spectrum—a proxy for the inertia–gravity wave energy spectrum—resembles a −5/3 power law in the mature stage. Divergent kinetic energy dominates the lower stratospheric mesoscale spectrum, accounting for its shallowing. Rotational kinetic energy, by contrast, dominates the upper tropospheric spectrum and no shallowing of the full spectrum is observed. By analyzing the tendency equation for the kinetic energy spectrum, it is shown that the lower stratospheric spectrum is not governed solely by a downscale energy cascade; rather, it is influenced by the vertical pressure flux divergence associated with vertically propagating inertia–gravity waves.

scholarly journals Characteristics of gravity waves generated in a baroclinic instability simulation

2015 ◽  
Vol 15 (22) ◽  
pp. 32639-32678
Author(s):  
Y.-H. Kim ◽  
H.-Y. Chun ◽  
S.-H. Park ◽  
I.-S. Song ◽  
H.-J. Choi
Keyword(s):  
Life Cycle ◽  
Gravity Waves ◽  
Baroclinic Instability ◽  
Mature Stage ◽  
Velocity Spectrum ◽  
Two Dimensional ◽  
Baroclinic Wave ◽  
Upper Troposphere ◽  
Westerly Jet ◽  
The Waves

Abstract. An idealized baroclinic instability case is simulated using a ~ 10 km resolution global model to investigate the characteristics of gravity waves (GWs) generated in the baroclinic life cycle. Three groups of GWs (W1–W3) appear around the high-latitude surface trough at the mature stage of the baroclinic wave. They have horizontal and vertical wavelengths of 40–400 and 2.9–9.8 km, respectively, in the upper troposphere. The two-dimensional phase-velocity spectrum of the waves is arc-shaped with a peak at 17 m s−1 eastward, which is difficult for the waves to propagate upward through the tropospheric westerly jet. At the breaking stage of the baroclinic wave, a midlatitude surface low is isolated from the higher-latitude trough, and two groups of quasi-stationary GWs (W4 and W5) appear near the surface low. These waves have horizontal and vertical wavelengths of 60–400 and 4.9–14 km, respectively, and are able to propagate vertically for long distances. The generation mechanism of the simulated GWs is discussed.

scholarly journals Characteristics of gravity waves generated in the jet-front system in a baroclinic instability simulation

2016 ◽  
Vol 16 (8) ◽  
pp. 4799-4815 ◽  
Author(s):  
Young-Ha Kim ◽  
Hye-Yeong Chun ◽  
Sang-Hun Park ◽  
In-Sun Song ◽  
Hyun-Joo Choi
Keyword(s):  
Life Cycle ◽  
Gravity Waves ◽  
Baroclinic Instability ◽  
Mature Stage ◽  
Velocity Spectrum ◽  
Two Dimensional ◽  
Baroclinic Wave ◽  
Upper Troposphere ◽  
Westerly Jet ◽  
The Waves

Abstract. An idealized baroclinic instability case is simulated using a  ∼  10 km resolution global model to investigate the characteristics of gravity waves generated in the baroclinic life cycle. Three groups of gravity waves appear around the high-latitude surface trough at the mature stage of the baroclinic wave. They have horizontal and vertical wavelengths of 40–400 and 2.9–9.8 km, respectively, in the upper troposphere. The two-dimensional phase-velocity spectrum of the waves is arc shaped with a peak at 17 m s−1 eastward. These waves have difficulty in propagating upward through the tropospheric westerly jet. At the breaking stage of the baroclinic wave, a midlatitude surface low is isolated from the higher-latitude trough, and two groups of quasi-stationary gravity waves appear near the surface low. These waves have horizontal and vertical wavelengths of 60–400 and 4.9–14 km, respectively, and are able to propagate vertically for long distances. The simulated gravity waves seem to be generated by surface fronts, given that the structures and speeds of wave phases are coherent with those of the fronts.

Semi-Lagrangian exponential time-integration method for the shallow water equations on the cubed sphere grid

2020 ◽  
Vol 35 (6) ◽  
pp. 355-366
Author(s):  
Vladimir V. Shashkin ◽  
Gordey S. Goyman
Keyword(s):  
Shallow Water ◽  
Gravity Waves ◽  
Shallow Water Equations ◽  
Time Integration ◽  
Standard Test ◽  
Integration Scheme ◽  
Test Problems ◽  
Cubed Sphere ◽  
Lagrangian Scheme ◽  
Inertia Gravity Waves

AbstractThis paper proposes the combination of matrix exponential method with the semi-Lagrangian approach for the time integration of shallow water equations on the sphere. The second order accuracy of the developed scheme is shown. Exponential semi-Lagrangian scheme in the combination with spatial approximation on the cubed-sphere grid is verified using the standard test problems for shallow water models. The developed scheme is as good as the conventional semi-implicit semi-Lagrangian scheme in accuracy of slowly varying flow component reproduction and significantly better in the reproduction of the fast inertia-gravity waves. The accuracy of inertia-gravity waves reproduction is close to that of the explicit time-integration scheme. The computational efficiency of the proposed exponential semi-Lagrangian scheme is somewhat lower than the efficiency of semi-implicit semi-Lagrangian scheme, but significantly higher than the efficiency of explicit, semi-implicit, and exponential Eulerian schemes.

Spontaneous-adjustment emission of inertia-gravity waves by unsteady vortical motion in the hurricane core

2010 ◽  
Vol 136 (647) ◽  
pp. 537-548 ◽  
Author(s):  
E. A. Hendricks ◽  
W. H. Schubert ◽  
S. R. Fulton ◽  
B. D. McNoldy
Keyword(s):  
Gravity Waves ◽  
Vortical Motion ◽  
Inertia Gravity Waves

scholarly journals Moist versus Dry Baroclinic Instability in a Simplified Two-Layer Atmospheric Model with Condensation and Latent Heat Release

2012 ◽  
Vol 69 (4) ◽  
pp. 1405-1426 ◽  
Author(s):  
Julien Lambaerts ◽  
Guillaume Lapeyre ◽  
Vladimir Zeitlin
Keyword(s):  
Life Cycle ◽  
Heat Release ◽  
Latent Heat ◽  
Baroclinic Instability ◽  
Underlying Mechanism ◽  
Linear Instability ◽  
Vapor Condensation ◽  
Water Model ◽  
Finite Volume Scheme ◽  
Latent Heat Release

Abstract The authors undertake a detailed analysis of the influence of water vapor condensation and latent heat release upon the evolution of the baroclinic instability. The framework consists in a two-layer rotating shallow-water model with moisture coupled to dynamics through mass exchange between the layers due to condensation/precipitation. The model gives all known in literature models of this kind as specific limits. It is fully nonlinear and ageostrophic. The reference state is a baroclinic Bickley jet. The authors first study its “dry” linear instability and then use the most unstable mode to initialize high-resolution numerical simulations of the life cycle of the instability in nonprecipitating (moisture being a passive tracer) and precipitating cases. A new-generation well-balanced finite-volume scheme is used in these simulations. The evolution in the nonprecipitating case follows the standard cyclonic wave-breaking life cycle of the baroclinic instability, which is reproduced with a high fidelity. In the precipitating case, the onset of condensation significantly increases the growth rate of the baroclinic instability at the initial stages due to production of available potential energy by the latent heat release. Condensation occurs in frontal regions and wraps up around the cyclone, which is consistent with the moist cyclogenesis theory and observations. Condensation induces a clear-cut cyclone–anticyclone asymmetry. The authors explain the underlying mechanism and show how it modifies the equilibration of the flow at the late stages of the saturation of the instability. In spite of significant differences in the evolution, only weak differences in various norms of the perturbations remain between precipitating and nonprecipitating cases at the end of the saturation process.

scholarly journals Intraseasonal Modulation of the Surface Cooling in the Gulf of Guinea

2013 ◽  
Vol 43 (2) ◽  
pp. 382-401 ◽  
Author(s):  
Julien Jouanno ◽  
Frédéric Marin ◽  
Yves du Penhoat ◽  
Jean-Marc Molines
Keyword(s):  
Mixed Layer ◽  
Gravity Waves ◽  
Heat Budget ◽  
Vertical Shear ◽  
Upper Ocean ◽  
Equatorial Waves ◽  
Gulf Of Guinea ◽  
The Core ◽  
Mixed Layer Heat Budget ◽  
Inertia Gravity Waves

Abstract A regional numerical model of the tropical Atlantic Ocean and observations are analyzed to investigate the intraseasonal fluctuations of the sea surface temperature at the equator in the Gulf of Guinea. Results indicate that the seasonal cooling in this region is significantly shaped by short-duration cooling events caused by wind-forced equatorial waves: mixed Rossby–gravity waves within the 12–20-day period band, inertia–gravity waves with periods below 11 days, and equatorially trapped Kelvin waves with periods between 25 and 40 days. In these different ranges of frequencies, it is shown that the wave-induced horizontal oscillations of the northern front of the mean cold tongue dominate the variations of mixed layer temperature near the equator. But the model mixed layer heat budget also shows that the equatorial waves make a significant contribution to the mixed layer heat budget through modulation of the turbulent cooling, especially above the core of the Equatorial Undercurrent (EUC). The turbulent cooling variability is found to be mainly controlled by the intraseasonal modulation of the vertical shear in the upper ocean. This mechanism is maximum during periods of seasonal cooling, especially in boreal summer, when the surface South Equatorial Current is strongest and between 2°S and the equator, where the presence of the EUC provides a background vertical shear in the upper ocean. It applies for the three types of intraseasonal waves. Inertia–gravity waves also modulate the turbulent heat flux at the equator through vertical displacement of the core of the EUC in response to equatorial divergence and convergence.

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