Response of GPS occultation signals to atmospheric gravity waves and retrieval of gravity wave parameters

AbstractAtmospheric gravity waves are a kind of mesoscale disturbance, commonly found in the atmospheric system, that plays a key role in a series of mesospheric dynamic processes. When propagating to the upper atmosphere, the gravity waves will disturb the local temperature and density, and then modulate the intensity of the surrounding airglow radiation. As a result, the presence of gravity waves on a moonless night can usually cause the airglow to reveal ripple features in low-light images. In this paper we have applied a two-dimensional Stockwell transform technique (2DST) to airglow measurements from nighttime low-light images of the day–night band on the Suomi National Polar-Orbiting Partnership. To our knowledge this study is the first to measure localized mesospheric gravity wave brightness amplitudes, horizontal wavelengths, and propagation directions using such a method and data. We find that the method can characterize the general shape and amplitude of concentric gravity wave patterns, capturing the dominant features and directions with a good degree of accuracy. The key strength of our 2DST application is that our approach could be tuned and then automated in the future to process tens of thousands of low-light images, globally characterizing gravity wave parameters in this historically poorly studied layer of the atmosphere.

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Atmospheric Gravity Wave Science in the Polar Regions

Eos ◽

10.1029/2019eo120071 ◽

2019 ◽

Vol 100 ◽

Author(s):

Tracy Moffat-Griffin ◽

Mike Taylor ◽

Takuji Nakamura ◽

Damian Murphy ◽

Jose Bageston ◽

...

Keyword(s):

Gravity Wave ◽

Gravity Waves ◽

Polar Regions ◽

Special Issue ◽

Atmospheric Gravity Wave ◽

Atmospheric Gravity Waves ◽

Global Circulation ◽

Atmospheric Gravity

A joint special issue explores the potential of collaboration to help understand atmospheric gravity waves in the Polar Regions and their effect on global circulation.

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The generation and propagation of atmospheric gravity waves observed during the Worldwide Atmospheric Gravity-wave Study (WAGS)

Journal of Atmospheric and Terrestrial Physics ◽

10.1016/0021-9169(88)90018-9 ◽

1988 ◽

Vol 50 (4-5) ◽

pp. 323-338 ◽

Cited By ~ 56

Author(s):

P.J.S. Williams ◽

G. Crowley ◽

K. Schlegel ◽

T.S. Virdi ◽

I. McCrea ◽

...

Keyword(s):

Gravity Wave ◽

Gravity Waves ◽

Atmospheric Gravity Wave ◽

Atmospheric Gravity Waves ◽

Atmospheric Gravity

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An Introduction to Atmospheric Gravity Waves

10.1016/s0074-6142(02)x8001-2 ◽

2002 ◽

Keyword(s):

Gravity Waves ◽

Atmospheric Gravity Waves ◽

Atmospheric Gravity

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Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra

Natural Hazards and Earth System Science ◽

10.5194/nhess-7-625-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 625-628 ◽

Cited By ~ 36

Author(s):

A. Rozhnoi ◽

M. Solovieva ◽

O. Molchanov ◽

P.-F. Biagi ◽

M. Hayakawa

Keyword(s):

Gravity Waves ◽

Fresnel Zone ◽

Signal Amplitude ◽

Magnetic Storms ◽

Frequency Range ◽

Atmospheric Gravity Waves ◽

Period Range ◽

Before And After ◽

Atmospheric Gravity ◽

Large Earthquakes

Abstract. We analyze variations of the LF subionospheric signal amplitude and phase from JJY transmitter in Japan (F=40 kHz) received in Petropavlovsk-Kamchatsky station during seismically quiet and active periods including also periods of magnetic storms. After 20 s averaging, the frequency range of the analysis is 0.28–15 mHz that corresponds to the period range from 1 to 60 min. Changes in spectra of the LF signal perturbations are found several days before and after three large earthquakes, which happened in November 2004 (M=7.1), August 2005 (M=7.2) and November 2006 (M=8.2) inside the Fresnel zone of the Japan-Kamchatka wavepath. Comparing the perturbed and background spectra we have found the evident increase in spectral range 10–25 min that is in the compliance with theoretical estimations on lithosphere-ionosphere coupling by the Atmospheric Gravity Waves (T>6 min). Similar changes are not found for the periods of magnetic storms.

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A study of atmospheric gravity waves and travelling ionospheric disturbances at equatorial latitudes

Annales Geophysicae ◽

10.1007/s00585-997-1048-4 ◽

1997 ◽

Vol 15 (8) ◽

pp. 1048-1056 ◽

Cited By ~ 41

Author(s):

R. L. Balthazor ◽

R. J. Moffett

Keyword(s):

Gravity Waves ◽

Large Scale ◽

Ionospheric Disturbance ◽

Magnetic Equator ◽

Ionospheric Disturbances ◽

Atmospheric Gravity Waves ◽

Opposite Hemisphere ◽

Travelling Ionospheric Disturbances ◽

F Region ◽

Atmospheric Gravity

Abstract. A global coupled thermosphere-ionosphere-plasmasphere model is used to simulate a family of large-scale imperfectly ducted atmospheric gravity waves (AGWs) and associated travelling ionospheric disturbances (TIDs) originating at conjugate magnetic latitudes in the north and south auroral zones and subsequently propagating meridionally to equatorial latitudes. A 'fast' dominant mode and two slower modes are identified. We find that, at the magnetic equator, all the clearly identified modes of AGW interfere constructively and pass through to the opposite hemisphere with unchanged velocity. At F-region altitudes the 'fast' AGW has the largest amplitude, and when northward propagating and southward propagating modes interfere at the equator, the TID (as parameterised by the fractional change in the electron density at the F2 peak) increases in magnitude at the equator. The amplitude of the TID at the magnetic equator is increased compared to mid-latitudes in both upper and lower F-regions with a larger increase in the upper F-region. The ionospheric disturbance at the equator persists in the upper F-region for about 1 hour and in the lower F-region for 2.5 hours after the AGWs first interfere, and it is suggested that this is due to enhancements of the TID by slower AGW modes arriving later at the magnetic equator. The complex effects of the interplays of the TIDs generated in the equatorial plasmasphere are analysed by examining neutral and ion winds predicted by the model, and are demonstrated to be consequences of the forcing of the plasmasphere along the magnetic field lines by the neutral air pressure wave.

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