Dispersion imposed limits on atmospheric gravity waves in the mesosphere: Observations from OH airglow

Swenson, G. R.; Alexander, M. Joan; Haque, Rezaul

doi:10.1029/1999gl010738

Cited by 40 publications

(44 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To distinguish the peaks caused by gravity waves from those caused by noise or other structures, several criteria were adopted as follows: Individual gravity waves should have a power greater than 10% of the total spectrum. Intensity amplitude is greater than 0.5% but less than 10%. An intensity amplitude larger than 10% might be caused by cloud or other strong structures; horizontal wavelengths are more than 12 km but less than 100 km.Waves with horizontal wavelengths of more than 100 km might be caused by the Milky Way, and waves with horizontal wavelengths of less than 12 km are too small to be observed by the airglow imager, considering the thickness of the OH airglow layer [ Swenson et al ., ].…”

Section: Methodsmentioning

confidence: 99%

Gravity wave characteristics in the mesopause region revealed from OH airglow imager observations over Northern Colorado

Tang

Dou

et al. 2014

JGR Space Physics

View full text Add to dashboard Cite

Using 5 years of all-sky OH airglow imager data over Yucca Ridge Field Station, CO (40.7°N, 104.9°W), from September 2003 to September 2008, we extract and deduce quasi-monochromatic gravity wave (GW) characteristics in the mesopause region. The intrinsic periods are clustered between approximately 4 and 10 min, and many of them are unstable and evanescent. GW occurrence frequency exhibits a clear semiannual variation with equinoctial minima, which is likely related to the seasonal variation of background wind. The anomalous propagation direction in January 2006, with strong southward before major warming starting in 21 January and weak southward propagation afterward, was most likely affected by stratospheric sudden warming. The momentum fluxes show strongly anticorrelated with the tides, with~180°out of phase in the zonal component. While in the meridional component, the easterly maximum occurred approximately 2-6 h after maximum easterly tidal wind. However, the anticorrelations are both weakest during the summer. The dissipating and breaking of small-scale and high-frequency GW's components could have a potential impact on the general circulation in the mesopause region.

show abstract

Section: Methodsmentioning

confidence: 99%

Gravity wave characteristics in the mesopause region revealed from OH airglow imager observations over Northern Colorado

Tang

Dou

et al. 2014

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…We excluded waves with horizontal wavelengths of less than 20 km, which cannot be distinguished from structures caused by local instability, such as ripples, and those with horizontal wavelengths of more than 100 km, which cannot be quantified fully due to our procedures for removing image contamination by the Milky Way. We also excluded waves with vertical wavelengths of less than 12 km, which essentially are too small to be observed by the airglow imaging considering the thickness of the emission layer (Swenson et al, 2000), and more than 60 km, which also might be ducted waves.…”

Section: Wave Identificationmentioning

confidence: 99%

Gravity wave momentum flux in the upper mesosphere derived from OH airglow imaging measurements

et al. 2007

View full text Add to dashboard Cite

We report procedures to identify small-scale (20-100 km) atmospheric gravity waves from OH airglow images to estimate momentum fluxes carried by the waves. We also deduce contamination of background continuum emission in OH image, by comparing a simultaneous observation of OH lines measured by the Spectral Airglow Temperature Imager (SATI). We applied the procedures to a one-night dataset obtained at Shigaraki, Japan (34.9• N, 136.1 • E) on November 19, 1999. The background wind, which is essential for deriving the intrinsic parameters of gravity waves, was measured by the Middle and Upper Atmosphere (MU) radar. Contamination of background continuum emission with the OH filter was deduced to be 30%. From these procedures, we found that the gravity waves identified in the OH images were mainly propagating southward or southeastward with horizontal wavelengths of 60-90 km and apparent phase speeds of 40-80 m/s. The estimated momentum fluxes on this night was 1-15 m 2 s −2 , with an average of 4.9 m 2 s −2 .

show abstract

“…3. Such waves are prone to be trapped in the atmosphere via highω reflection (Isler et al, 1997;Swenson et al, 2000;Marks and Eckermann, 1995), and the trapped waves carry no net vertical flux of horizontal momentum. To see how many of the waves events were likely trapped or evanescent waves instead of propagating waves, we show on the left panel of Fig.…”

Section: Discussionmentioning

confidence: 99%

Small-scale gravity waves in ER-2 MMS/MTP wind and temperature measurements during CRYSTAL-FACE

et al. 2006

View full text Add to dashboard Cite

Abstract. Lower stratospheric wind and temperature measurements made from NASA's high-altitude ER-2 research aircraft during the CRYSTAL-FACE campaign in July 2002 were analyzed to retrieve information on small scale gravity waves (GWs) at the aircraft's flight level (typically ∼ 20 km altitude). For a given flight segment, the S-transform (a Gaussian wavelet transform) was used to search for and identify small horizontal scale GW events, and to estimate their apparent horizontal wavelengths. The horizontal propagation directions of the events were determined using the Stokes parameter method combined with the cross S-transform analysis. The vertical temperature gradient was used to determine the vertical wavelengths of the events. GW momentum fluxes were calculated from the cross S-transform. Other wave parameters such as intrinsic frequenciesω were calculated using the GW dispersion relation. More than 100 GW events were identified. They were generally high frequency waves with vertical wavelength of ∼5 km and horizontal wavelength generally shorter than 20 km. Their intrinsic propagation directions were predominantly toward the east, whereas their ground-based propagation directions were primarily toward the west. Among the events, ∼20% of them had very short horizontal wavelength, very high intrinsic frequency, and relatively small momentum fluxes, and thus they were likely trapped in the lower stratosphere.Using the estimated GW parameters and the background winds and stabilities from the NCAR/NCEP reanalysis data, we were able to trace the sources of the events using a simple reverse ray-tracing. More than 70% of the events were traced back to convective sources in the troposphere, and the sources were generally located upstream of the locations of the events observed at the aircraft level. Finally, a probability density function of the reversible cooling rate due to

show abstract

Dispersion imposed limits on atmospheric gravity waves in the mesosphere: Observations from OH airglow

Abstract: Dispersion ConsiderationsAll other things being equal, a wave with higher intrinsic phase speed will carry proportionately more momentum flux than a wave with lower intrinsic phase speed. The airglow images are most sensitive to these high intrinsic phase speed waves.

Cited by 40 publications

References 11 publications

Gravity wave characteristics in the mesopause region revealed from OH airglow imager observations over Northern Colorado

Gravity wave characteristics in the mesopause region revealed from OH airglow imager observations over Northern Colorado

Gravity wave momentum flux in the upper mesosphere derived from OH airglow imaging measurements

Small-scale gravity waves in ER-2 MMS/MTP wind and temperature measurements during CRYSTAL-FACE

Contact Info

Product

Resources

About