Gravity Wave Propagation from the Stratosphere into the Mesosphere Studied with Lidar, Meteor Radar, and TIMED/SABER

A low-frequency inertial atmospheric gravity wave (AGW) event was studied with lidar (40.5° N, 116° E), meteor radar (40.3° N, 116.2° E), and TIMED/SABER at Beijing on 30 May 2012. Lidar measurements showed that the atmospheric temperature structure was persistently perturbed by AGWs propagating upward from the stratosphere into the mesosphere (35–86 km). The dominant contribution was from the waves with vertical wavelengths λ z = 8 − 10 km and wave periods T ob = 6.6 ± 0.7 h . Simultaneous observations from a meteor radar illustrated that MLT horizontal winds were perturbed by waves propagating upward with an azimuth angle of θ = 247 ° , and the vertical wavelength ( λ z = 10 km ) and intrinsic period ( T in = 7.4 h ) of the dominant waves were inferred with the hodograph method. TIMED/SABER measurements illustrated that the vertical temperature profiles were also perturbed by waves with dominant vertical wavelength λ z = 6 − 9 km . Observations from three different instruments were compared, and it was found that signatures in the temperature perturbations and horizontal winds were induced by identical AGWs. According to these coordinated observation results, the horizontal wavelength and intrinsic phase speed were inferred to be ~560 km and ~21 m/s, respectively. Analyses of the Brunt-Väisälä frequency and potential energy illustrated that this persistent wave propagation had good static stability.

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Airglow Measurements of Gravity Wave Propagation and Damping over Kolhapur (16.5°N, 74.2°E)

International Journal of Geophysics ◽

10.1155/2014/514937 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

R. N. Ghodpage ◽

A. Taori ◽

P. T. Patil ◽

S. Gurubaran ◽

A. K. Sharma ◽

...

Keyword(s):

Wave Propagation ◽

Gravity Wave ◽

Meridional Wind ◽

Vertical Wavelength ◽

Emission Layer ◽

Positive Correlation ◽

Intensity Measurements ◽

Wind Shears ◽

The Waves ◽

Airglow Intensity

Simultaneous mesospheric OH and O (1S) night airglow intensity measurements from Kolhapur (16.8°N, 74.2°E) reveal unambiguous gravity wave signatures with periods varying from 01 hr to 9 hr with upward propagation. The amplitudes growth of these waves is found to vary from 0.4 to 2.2 while propagating from the OH layer (~87 km) to the O (1S) layer (~97 km). We find that vertical wavelength of the observed waves increases with the wave period. The damping factors calculated for the observed waves show large variations and that most of these waves were damped while traveling from the OH emission layer to the O (1S) emission layer. The damping factors for the waves show a positive correlation at vertical wavelengths shorter than 40 km, while a negative correlation at higher vertical wavelengths. We note that the damping factors have stronger positive correlation with meridional wind shears compared to the zonal wind shears.

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Atmospheric gravity wave propagation direction observed by airglow imaging in the South American sector

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2005.03.015 ◽

2005 ◽

Vol 67 (17-18) ◽

pp. 1767-1773 ◽

Cited By ~ 7

Author(s):

A.F. Medeiros ◽

H. Takahashi ◽

R.A. Buriti ◽

K.M. Pinheiro ◽

D. Gobbi

Keyword(s):

Wave Propagation ◽

Gravity Wave ◽

Propagation Direction ◽

South American ◽

The South ◽

Atmospheric Gravity Wave ◽

Wave Propagation Direction ◽

Atmospheric Gravity

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Simulation of non-hydrostatic gravity wave propagation in the upper atmosphere

Annales Geophysicae ◽

10.5194/angeo-32-443-2014 ◽

2014 ◽

Vol 32 (4) ◽

pp. 443-447 ◽

Cited By ~ 11

Author(s):

Y. Deng ◽

A. J. Ridley

Keyword(s):

Wave Propagation ◽

Gravity Wave ◽

High Frequency ◽

General Circulation ◽

Low Frequency ◽

Circulation Model ◽

Horizontal Resolution ◽

Upper Atmosphere ◽

Cutoff Wavelength ◽

Frequency Wave

Abstract. The high-frequency and small horizontal scale gravity waves may be reflected and ducted in non-hydrostatic simulations, but usually propagate vertically in hydrostatic models. To examine gravity wave propagation, a preliminary study has been conducted with a global ionosphere–thermosphere model (GITM), which is a non-hydrostatic general circulation model for the upper atmosphere. GITM has been run regionally with a horizontal resolution of 0.2° long × 0.2° lat to resolve the gravity wave with wavelength of 250 km. A cosine wave oscillation with amplitude of 30 m s−1 has been applied to the zonal wind at the low boundary, and both high-frequency and low-frequency waves have been tested. In the high-frequency case, the gravity wave stays below 200 km, which indicates that the wave is reflected or ducted in propagation. The results are consistent with the theoretical analysis from the dispersion relationship when the wavelength is larger than the cutoff wavelength for the non-hydrostatic situation. However, the low-frequency wave propagates to the high altitudes during the whole simulation period, and the amplitude increases with height. This study shows that the non-hydrostatic model successfully reproduces the high-frequency gravity wave dissipation.

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The Compressional Beta Effect: Analytical Solution, Numerical Benchmark, and Data Analysis

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-20-0124.1 ◽

2020 ◽

Vol 77 (11) ◽

pp. 3721-3732

Author(s):

Hing Ong ◽

Paul E. Roundy

Keyword(s):

Large Scale ◽

Rossby Waves ◽

Numerical Models ◽

Phase Speed ◽

Static Stability ◽

Propagation Mechanism ◽

Vertical Wavelength ◽

Wave Solutions ◽

Beta Effect ◽

Vorticity Tendency

AbstractThis study derives a complete set of equatorially confined wave solutions from an anelastic equation set with the complete Coriolis terms, which include both the vertical and meridional planetary vorticity. The propagation mechanism can change with the effective static stability. When the effective static stability reduces to neutral, buoyancy ceases, but the role of buoyancy as an eastward-propagation mechanism is replaced by the compressional beta effect (i.e., vertical density-weighted advection of the meridional planetary vorticity). For example, the Kelvin mode becomes a compressional Rossby mode. Compressional Rossby waves are meridional vorticity disturbances that propagate eastward owing to the compressional beta effect. The compressional Rossby wave solutions can serve as a benchmark to validate the implementation of the nontraditional Coriolis terms (NCTs) in numerical models; with an effectively neutral condition and initial large-scale disturbances given a half vertical wavelength spanning the troposphere on Earth, compressional Rossby waves are expected to propagate eastward at a phase speed of 0.24 m s−1. The phase speed increases with the planetary rotation rate and the vertical wavelength and also changes with the density scale height. Besides, the compressional beta effect and the meridional vorticity tendency are reconstructed using reanalysis data and regressed upon tropical precipitation filtered for the Madden–Julian oscillation (MJO). The results suggest that the compressional beta effect contributes 10.8% of the meridional vorticity tendency associated with the MJO in terms of the ratio of the minimum values.

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Latitudinal Variations of the Convective Source and Propagation Condition of Inertio-Gravity Waves in the Tropics

Journal of the Atmospheric Sciences ◽

10.1175/jas3891.1 ◽

2007 ◽

Vol 64 (5) ◽

pp. 1603-1618 ◽

Cited By ~ 10

Author(s):

Hye-Yeong Chun ◽

Jung-Suk Goh ◽

In-Sun Song ◽

Lucrezia Ricciardulli

Keyword(s):

Wave Propagation ◽

Gravity Waves ◽

Low Frequency ◽

Phase Speed ◽

Simple Relationship ◽

Propagation Condition ◽

Zonal Wavenumber ◽

Vertical Propagation ◽

Latitudinal Variations ◽

The Tropics

Abstract Latitudinal variations of the convective source and vertical propagation condition of inertio-gravity waves (IGWs) in the tropical region (30°S–30°N) are examined using high-resolution Global Cloud Imagery (GCI) and 6-hourly NCEP–NCAR reanalysis data, respectively, for 1 yr (March 1985–February 1986). The convective source is estimated by calculating the deep convective heating (DCH) rate using the brightness temperature of the GCI data. The latitudinal variation of DCH is found to be significant throughout the year. The ratio of the maximum to minimum values of DCH in the annual mean is 3.2 and it is much larger in the June–August (JJA) and December–February (DJF) means. Spectral analyses show that DCH has a dominant period of 1 day, a zonal wavelength of about 1600 km, and a Gaussian-type phase-speed spectrum with a peak at the zero phase speed. The vertical propagation condition of IGWs is determined, in the zonal wavenumber and frequency domain, by two factors: (i) latitude, which determines the Coriolis parameter, and (ii) the basic-state wind structure in the target height range of wave propagation. It was found that the basic-state wind significantly influences the wave propagation condition in the lower stratosphere between 150 and 30 hPa, and accordingly a large portion of the source spectrum is filtered out. This is prominent not only in the latitudes higher than 15° where strong negative shear exists, but also near the equator where strong positive shear associated with the westerly phase of the quasi-biennial oscillation (QBO) filters out large portions of the low-frequency components of the convective source. There is no simple relationship between the ground-based frequency and latitude; lower latitudes are not always favorable for low-frequency IGWs to be observed in the stratosphere. The basic-state wind in the Tropics, which has seasonal, annual, and interannual variations, plays a major role not only in determining the wave propagation condition in the stratosphere but also in producing convective sources in the troposphere.

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