A statistical investigation of inertia gravity wave activity based on MST radar observations at Xianghe (116.9°E, 39.8°N), China

Abstract. Turbulent kinetic energy dissipation rates (ε) and eddy diffusion coefficients (Kz) in the tropical mesosphere over Gadanki (13.5° N, 79.2° E), estimated from Doppler widths of MST radar echoes (vertical beam), observed over a 3-year period, show a seasonal variation with a dominant summer maximum. The observed seasonal variation of ε and Kz in the mesosphere is only partially consistent with that of gravity wave activity inferred from mesospheric winds and temperatures measured by rockets for a period of 9 years at Trivandrum (8.5° N, 77° E) (which shows two equinox and one summer maxima) lying close to Gadanki. The summer maximum of mesospheric ε and Kz values appears to be related to the enhanced gravity wave activity over the low-latitude Indian subcontinent during the southwest monsoon period (June – September). Both ε and Kz in the mesosphere over Gadanki show an increase with an increase in height during all seasons. The absolute values of observed ε and Kz in the mesosphere (above ~80 km) does not show significant differences from those reported for high latitudes. Comparison of observed Kz values during the winter above Gadanki with those over Arecibo (18.5° N, 66° W) shows that they are not significantly different from each other above the ~80 km altitude.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; tropical meteorology; wave and tides)

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Indian MST radar observations of gravity wave activities associated with tropical convection

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/s1364-6826(01)00040-2 ◽

2001 ◽

Vol 63 (15) ◽

pp. 1631-1642 ◽

Cited By ~ 17

Author(s):

S.K Dhaka ◽

P.K Devrajan ◽

Y Shibagaki ◽

R.K Choudhary ◽

S Fukao

Keyword(s):

Gravity Wave ◽

Tropical Convection ◽

Radar Observations ◽

Mst Radar

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MST Radar Observations of a Saturated Gravity Wave Spectrum

Journal of the Atmospheric Sciences ◽

10.1175/1520-0469(1989)046<2440:mrooas>2.0.co;2 ◽

1989 ◽

Vol 46 (15) ◽

pp. 2440-2447 ◽

Cited By ~ 146

Author(s):

T. Tsuda ◽

T. Inoue ◽

S. Kato ◽

S. Fukao ◽

D. C. Fritts ◽

...

Keyword(s):

Gravity Wave ◽

Wave Spectrum ◽

Radar Observations ◽

Mst Radar

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Long-term MST radar observations of vertical wave number spectra of gravity waves in the tropical troposphere over Gadanki (13.5° N, 79.2° E): comparison with model spectra

Annales Geophysicae ◽

10.5194/angeo-26-1671-2008 ◽

2008 ◽

Vol 26 (7) ◽

pp. 1671-1680 ◽

Cited By ~ 9

Author(s):

A. Narendra Babu ◽

K. Kishore Kumar ◽

G. Kishore Kumar ◽

M. Venkat Ratnam ◽

S. Vijaya Bhaskara Rao ◽

...

Keyword(s):

Kinetic Energy ◽

Gravity Wave ◽

Gravity Waves ◽

Total Kinetic Energy ◽

Wave Number ◽

Radar Observations ◽

Model Spectrum ◽

Wave Numbers ◽

Mst Radar ◽

Tropical Troposphere

Abstract. The potential utility of Mesosphere-Stratosphere-Troposphere (MST) radar measurements of zonal, meridional and vertical winds for divulging the gravity wave vertical wave number spectra is discussed. The data collected during the years 1995–2004 are used to obtain the mean vertical wave number spectra of gravity wave kinetic energy in the tropical troposphere over Gadanki (13.5° N, 79.2° E). First, the climatology of 3-dimensional wind components is developed using ten years of radar observations, for the first time, over this latitude. This climatology brought out the salient features of background tropospheric winds over Gadanki. Further, using the second order polynomial fit as background, the day-to-day wind anomalies are estimated. These wind anomalies in the 4–14 km height regions are used to estimate the profiles of zonal, meridional and vertical kinetic energy per unit mass, which are then used to estimate the height profile of total kinetic energy. Finally, the height profiles of total kinetic energy are subjected to Fourier analysis to obtain the monthly mean vertical wave number spectra of gravity wave kinetic energy. The monthly mean vertical wave number spectra are then compared with a saturation spectrum predicted by gravity wave saturation theory. A slope of 5/3 is used for the model gravity wave spectrum estimation. In general, the agreement is good during all the months. However, it is noticed that the model spectrum overestimates the PSD at lower vertical wave numbers and underestimates it at higher vertical wave numbers, which is consistently observed during all the months. The observed discrepancies are attributed to the differences in the slopes of theoretical and observed gravity wave spectra. The slopes of the observed vertical wave number spectra are estimated and compared with the model spectrum slope, which are in good agreement. The estimated slopes of the observed monthly vertical wave number spectra are in the range of −2 to −2.8. The significance of the present study lies in using the ten years of data to estimate the monthly mean vertical wave number spectra of gravity waves, which will find their application in representing the realistic gravity wave characteristics in atmospheric models.

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Inertia gravity wave activity in the troposphere and lower stratosphere observed by Wuhan MST radar

Science China Earth Sciences ◽

10.1007/s11430-015-5253-9 ◽

2016 ◽

Vol 59 (5) ◽

pp. 1066-1073

Author(s):

HaiYin Qing ◽

Chen Zhou ◽

ZhengYu Zhao ◽

BinBin Ni ◽

YuanNong Zhang

Keyword(s):

Gravity Wave ◽

Lower Stratosphere ◽

Wave Activity ◽

Mst Radar

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Gravity wave propagation studies using the Indian MST radar observations

Advances in Space Research ◽

10.1016/j.asr.2011.11.026 ◽

2012 ◽

Vol 49 (4) ◽

pp. 716-724 ◽

Cited By ~ 2

Author(s):

S.C. Chakravarty

Keyword(s):

Wave Propagation ◽

Gravity Wave ◽

Radar Observations ◽

Mst Radar

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Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus

Earth Planets and Space ◽

10.1186/s40623-019-1106-7 ◽

2019 ◽

Vol 71 (1) ◽

Author(s):

Takeru Yamada ◽

Takeshi Imamura ◽

Tetsuya Fukuhara ◽

Makoto Taguchi

Keyword(s):

Layer Thickness ◽

Gravity Wave ◽

Local Time ◽

Gravity Waves ◽

Analytical Approach ◽

Wave Activity ◽

Neutral Layer ◽

Low Latitudes ◽

Vertical Propagation ◽

The Waves

AbstractThe reason for stationary gravity waves at Venus’ cloud top to appear mostly at low latitudes in the afternoon is not understood. Since a neutral layer exists in the lower part of the cloud layer, the waves should be affected by the neutral layer before reaching the cloud top. To what extent gravity waves can propagate vertically through the neutral layer has been unclear. To examine the possibility that the variation of the neutral layer thickness is responsible for the dependence of the gravity wave activity on the latitude and the local time, we investigated the sensitivity of the vertical propagation of gravity waves on the neutral layer thickness using a numerical model. The results showed that stationary gravity waves with zonal wavelengths longer than 1000 km can propagate to the cloud-top level without notable attenuation in the neutral layer with realistic thicknesses of 5–15 km. This suggests that the observed latitudinal and local time variation of the gravity wave activity should be attributed to processes below the cloud. An analytical approach also showed that gravity waves with horizontal wavelengths shorter than tens of kilometers would be strongly attenuated in the neutral layer; such waves should originate in the altitude region above the neutral layer.

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