Interaction of gravity waves with the QBO: A satellite perspective

Ern, Manfred; Ploeger, Felix; Preusse, Peter; Gille, J. C.; Gray, Lesley J.; Kalisch, Silvio; Mlynczak, Martin G.; Russell, James M.; Riese, Martin

doi:10.1002/2013jd020731

Cited by 134 publications

(210 citation statements)

References 88 publications

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“…Furthermore, it raises questions about the reliability of AoA simulations from models without a QBO. In particular, uncertainties in the representation of the QBO in models, related to the prominent role of gravity waves in driving the QBO [e.g., Ern et al, 2014], may cause uncertainties in simulating interannual mean age variability.…”

Section: Discussionmentioning

confidence: 99%

Variability of stratospheric mean age of air and of the local effects of residual circulation and eddy mixing

et al. 2015

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We analyze the variability of mean age of air (AoA) and of the local effects of the stratospheric residual circulation and eddy mixing on AoA within the framework of the isentropic zonal mean continuity equation. AoA for the period 1988–2013 has been simulated with the Lagrangian chemistry transport model CLaMS driven by ERA‐Interim winds and diabatic heating rates. Model simulated AoA in the lower stratosphere shows good agreement with both in situ observations and satellite observations from Michelson Interferometer for Passive Atmospheric Sounding, even regarding interannual variability and changes during the last decade. The interannual variability throughout the lower stratosphere is largely affected by the quasi‐biennial‐oscillation‐induced circulation and mixing anomalies, with year‐to‐year AoA changes of about 0.5 years. The decadal 2002–2012 change shows decreasing AoA in the lowest stratosphere, below about 450 K. Above, AoA increases in the Northern Hemisphere and decreases in the Southern Hemisphere. Mixing appears to be crucial for understanding AoA variability, with local AoA changes resulting from a close balance between residual circulation and mixing effects. Locally, mixing increases AoA at low latitudes (40°S–40°N) and decreases AoA at higher latitudes. Strongest mixing occurs below about 500 K, consistent with the separation between shallow and deep circulation branches. The effect of mixing integrated along the air parcel path, however, significantly increases AoA globally, except in the polar lower stratosphere. Changes of local effects of residual circulation and mixing during the last decade are supportive of a strengthening shallow circulation branch in the lowest stratosphere and a southward shifting circulation pattern above.

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Section: Discussionmentioning

confidence: 99%

Variability of stratospheric mean age of air and of the local effects of residual circulation and eddy mixing

et al. 2015

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“…In addition to GWMF it is also possible to obtain estimates of the so-called "residual drag" from assimilated data (Alexander and Rosenlof, 2003;Pulido and Thuburn, 2006;Ern et al, 2014). Observed GWMF and the drag exerted by GWs can be used together to constrain e.g., a GW parameterization scheme.…”

Section: Discussionmentioning

confidence: 99%

“…Noise levels for HIRDLS and SABER as well as the references where to find them are given in Ern et al (2014). This compares to typical GW amplitudes of a few K in the stratosphere and more than 10 K in the upper mesosphere.…”

Section: B2 Noisementioning

confidence: 92%

“…This process strongly depends on the refraction of the GWs by the background wind field, thus forming a two-way interaction between mean winds and GWs. Hence, GWs significantly affect the global circulation and are the main driver of the quasi-biennial oscillation (QBO) (e.g., Dunkerton, 1997;Ern and Preusse, 2009;Alexander and Ortland, 2010;Evan et al, 2012;Ern et al, 2014). In addition, gravity waves also play a key role in wind reversals in the mesosphere and lower thermosphere (Lindzen, 1981;Matsuno, 1982;Ern et al, 2013), and they cause the cold summer mesopause (e.g., Björn, 1984).…”

Section: Introductionmentioning

confidence: 99%

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A comprehensive observational filter for satellite infrared limb sounding of gravity waves

Trinh¹,

Kalisch²,

Preusse³

et al. 2015

Atmos. Meas. Tech.

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Abstract. This paper describes a comprehensive observational filter for satellite infrared limb sounding of gravity waves. The filter considers instrument visibility and observation geometry with a high level of accuracy. It contains four main processes: visibility filter, projection of the wavelength on the tangent-point track, aliasing effect, and calculation of the observed vertical wavelength. The observation geometries of the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) and HIRDLS (High Resolution Dynamics Limb Sounder) are mimicked. Gravity waves (GWs) simulated by coupling a convective GW source (CGWS) scheme and the gravity wave regional or global ray tracer (GROGRAT) are used as an example for applying the observational filter. Simulated spectra in terms of horizontal and vertical wave numbers (wavelengths) of gravity wave momentum flux (GWMF) are analyzed under the influence of the filter. We find that the most important processes, which have significant influence on the spectrum are the visibility filter (for both SABER and HIRDLS observation geometries) and aliasing for SABER and projection on tangent-point track for HIRDLS. The vertical wavelength distribution is mainly affected by the retrieval as part of the "visibility filter" process. In addition, the short-horizontalscale spectrum may be projected for some cases into a longer horizontal wavelength interval which originally was not populated. The filter largely reduces GWMF values of very short horizontal wavelength waves. The implications for interpreting observed data are discussed.

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“…In particular, absolute gravity wave momentum fluxes are derived from information about gravity wave vertical and horizontal wavelengths (Alexander et al, 2008;Wright et al, 2010;Ern et al, 2011). Based on these momentum fluxes, the intermittency in gravity wave global distributions was studied (e.g., Hertzog et al, 2012;Wright et al, 2013), as well as the interaction of gravity waves with the background circulation (e.g., Ern et al, 2014Ern et al, , 2015. In addition Geller et al (2013) used HIRDLS data to compare gravity wave momentum fluxes in models and those derived from observations.…”

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confidence: 99%

Intercomparison of AIRS and HIRDLS stratospheric gravity wave observations

Meyer¹,

Ern²,

Hoffmann³

et al. 2018

Atmos. Meas. Tech.

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Abstract. We investigate stratospheric gravity wave observations by the Atmospheric InfraRed Sounder (AIRS) aboard NASA's Aqua satellite and the High Resolution Dynamics Limb Sounder (HIRDLS) aboard NASA's Aura satellite. AIRS operational temperature retrievals are typically not used for studies of gravity waves, because their vertical and horizontal resolution is rather limited. This study uses data of a high-resolution retrieval which provides stratospheric temperature profiles for each individual satellite footprint. Therefore the horizontal sampling of the high-resolution retrieval is 9 times better than that of the operational retrieval. HIRDLS provides 2-D spectral information of observed gravity waves in terms of along-track and vertical wavelengths. AIRS as a nadir sounder is more sensitive to short-horizontal-wavelength gravity waves, and HIRDLS as a limb sounder is more sensitive to short-vertical-wavelength gravity waves. Therefore HIRDLS is ideally suited to complement AIRS observations. A calculated momentum flux factor indicates that the waves seen by AIRS contribute significantly to momentum flux, even if the AIRS temperature variance may be small compared to HIRDLS. The stratospheric wave structures observed by AIRS and HIRDLS often agree very well. Case studies of a mountain wave event and a non-orographic wave event demonstrate that the observed phase structures of AIRS and HIRDLS are also similar. AIRS has a coarser vertical resolution, which results in an attenuation of the amplitude and coarser vertical wavelengths than for HIRDLS. However, AIRS has a much higher horizontal resolution, and the propagation direction of the waves can be clearly identified in geographical maps. The horizontal orientation of the phase fronts can be deduced from AIRS 3-D temperature fields. This is a restricting factor for gravity wave analyses of limb measurements. Additionally, temperature variances with respect to stratospheric gravity wave activity are compared on a statistical basis. The complete HIRDLS measurement period from January 2005 to March 2008 is covered. The seasonal and latitudinal distributions of gravity wave activity as observed by AIRS and HIRDLS agree well. A strong annual cycle at mid-and high latitudes is found in time series of gravity wave variances at 42 km, which has its maxima during wintertime and its minima during summertime. The variability is largest during austral wintertime at 60 • S. Variations in the zonal winds at 2.5 hPa are associated with large variability in gravity wave variances. Altogether, gravity wave variances of AIRS and HIRDLS are complementary to each other. Large parts of the gravity wave spectrum are covered by joint observations. This opens up fascinating vistas for future gravity wave research.

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Interaction of gravity waves with the QBO: A satellite perspective

Cited by 134 publications

References 88 publications

Variability of stratospheric mean age of air and of the local effects of residual circulation and eddy mixing

Variability of stratospheric mean age of air and of the local effects of residual circulation and eddy mixing

A comprehensive observational filter for satellite infrared limb sounding of gravity waves

Intercomparison of AIRS and HIRDLS stratospheric gravity wave observations

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