A statistical study of the structure, saturation and sources of inertio-gravity waves in the lower stratosphere observed with the MU radar

Sato, K.

doi:10.1016/0021-9169(94)90131-7

Cited by 174 publications

(208 citation statements)

References 36 publications

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“…The maximum in winter is consistent with previous GW studies using radiosondes (Allen and Vincent, 1995;Wang and Geller, 2003) and radars (Sato, 1994). The strong spring circulation in the SH is consistent with the fact that the GW energy is maximized in spring in the high-latitude region (Pfenninger et al, 1999;Yoshiki and Sato, 2000).…”

Section: Seasonal Variation Of the Potential Gw Contribution And Its supporting

confidence: 90%

The Climatology of Brewer-Dobson Circulation and the Contribution of Gravity Waves

Sato¹,

Hirano²

2018

Preprint

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Abstract. The climatology of residual mean circulation, which is a main component of Brewer-Dobson circulation, and the potential contribution of gravity waves (GWs) are examined for the annual mean state and for each season based on the transformed-Eulerian mean zonal momentum equation using modern four reanalysis data, which allows us to examine the whole stratosphere. First, the potential contribution of Rossby waves (RWs) to residual mean circulation is estimated from Eliassen-Palm flux divergence. The rest of residual-mean circulation, from which the potential RW contribution and zonal 10 mean zonal wind tendency are subtracted, is regarded as the potential GW contribution. These potential wave contributions are exact contributions for the annual mean state and give good approximates for solstitial seasons. The GWs contribute to drive not only the summer hemispheric part of the winter deep branch and low-latitude part of shallow branches, as indicated by previous studies, but also cause a higher-latitude extension of the deep circulation in all seasons except for summer. This GW contribution is essential to determine the location of the turn-around latitude. The autumn circulation is stronger and wider 15 than that of spring in the equinoctial seasons, regardless of almost symmetric RW and GW contributions around the equator. This asymmetry is attributable to the existence of the spring-to-autumn pole circulation corresponding to the angular momentum transport associated with seasonal variation due to the radiative process. The potential GW contribution is larger in September-to-November than in March-to-May in both hemispheres. The upward mass flux is maximized in the boreal winter in the lower stratosphere, while it exhibits semi-annual variation in the upper stratosphere. The GW contribution to the 20 annual mean upward mass flux is in a range of 10-30 %, depending on the reanalysis data. The boreal winter maximum in the lower stratosphere is attributable to stronger RW activity in both hemispheres than in the austral winter.

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Section: Seasonal Variation Of the Potential Gw Contribution And Its supporting

confidence: 90%

The Climatology of Brewer-Dobson Circulation and the Contribution of Gravity Waves

Sato¹,

Hirano²

2018

Preprint

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“…1, 2 represent inertia-gravity waves, studies such as Thomas et al (1992), Sato (1994) and Cho (1995) show that their horizontal wavelength is typically hundreds of kilometres. Since their vertical wavelength is about 2 km, the slope of the phase fronts would be approximately 1 .…”

Section: Instability Of Long-period Wavesmentioning

confidence: 99%

Long-period unstable gravity-waves and associated VHF radar echoes

Worthington

Thomas

1997

Ann. Geophys.

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Abstract. VHF atmospheric radar is used to measure the wind velocity and radar echo power related to longperiod wind perturbations, including gravity waves, which are observed commonly in the lower stratosphere and tropopause region, and sometimes in the troposphere. These wind structures have been identi®ed previously as either inertia-gravity waves, often associated with jet streams, or mountain waves. At heights of peak wind shear, imbalances are found between the echo powers of a symmetric pair of radar beams, which are expected to be equal. The largest of these power di erences are found for conditions of simultaneous high wind shear and high aspect sensitivity. It is suggested that the e ect might arise from tilted specular re¯ectors or anisotropic turbulent scatterers, a result of, for example, Kelvin-Helmholtz instabilities generated by the strong wind shears. This radar power-di erence e ect could o er information about the onset of saturation in long-period waves, and the formation of thin layers of turbulence.

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“…Sato [ 1994] examined the detailed characteristics of gravity waves using a mesosphere, stratosphere, and troposphere (MST) radar operating in Japan (35øN, 165øE). She found that the vertical flux of zonal momentum is negative in winter and mostly zero in summer and considered topographically forced gravity waves to be the most plausible cause of the negative momentum fluxes in winter.…”

Section: Introductionmentioning

confidence: 99%

“…She also showed the dominance of gravity waves propagating equatorward above the subtropical jet in winter. In the equatorial lower stratosphere, gravity wave intensity has a dominant variation synchronized with the quasi-biennial oscillation of the mean zonal wind rather than the annual variation [Sato et al, 1994;Maruyarna, 1994]. In the Southern Hemisphere, Allen and Vincent [ 1995] examined gravity wave energy in the latitudinal range of 12ø-68øS.…”

Section: Introductionmentioning

confidence: 99%

A statistical study of gravity waves in the polar regions based on operational radiosonde data

Yoshiki¹,

Sato²

2000

J. Geophys. Res.

122

184

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Abstract. Gravity waves in the lower polar stratosphere are examined using operational radiosonde observations gathered from 33 stations over a period of 10 years. Both the potential and kinetic energies of the gravity waves vary annually and reach maxima in winter in the Arctic and in spring in the Antarctic. In the Antarctic spring a region of large gravity wave energy propagates downward following the movement of a zone of high static stability associated with Southern Hemispheric warming. Moreover, the enhanced energy region and the high stability zone coincide in the horizontal plane and move gradually from 135øE, 50øS to 45øW, 70øS over the South Pole. The vertical and horizontal directions of wave propagation are examined using hodograph analysis in the vertical. Most gravity waves transfer energy upward in the Arctic, while the percentage of downward energy propagation is relatively high in winter and spring in the Antarctic. Horizontally, gravity waves propagate westward relative to the mean wind in the Arctic, while in the Antarctic the dominant direction varies from station to station. The correlation between gravity wave energy in the lower stratosphere and the mean wind is also examined. In the Arctic, gravity wave energy is highly correlated with the surface wind, though in the Antarctic it correlates with the stratospheric wind. These results suggest that gravity waves observed in the Arctic are forced by topography, whereas in Antarctica some sources may exist in the stratosphere. One such source candidate is likely to be the polar night jet.

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A statistical study of the structure, saturation and sources of inertio-gravity waves in the lower stratosphere observed with the MU radar

Cited by 174 publications

References 36 publications

The Climatology of Brewer-Dobson Circulation and the Contribution of Gravity Waves

The Climatology of Brewer-Dobson Circulation and the Contribution of Gravity Waves

Long-period unstable gravity-waves and associated VHF radar echoes

A statistical study of gravity waves in the polar regions based on operational radiosonde data

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