Evidence for interhemispheric stratosphere‐mesosphere coupling derived from noctilucent cloud properties

Karlsson, Bodil; Körnich, Heiner; Gumbel, J.

doi:10.1029/2007gl030282

Cited by 103 publications

(155 citation statements)

References 21 publications

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“…7) seasonal inter-hemispheric differences in the subtropics in this altitude region might be anticipated. Recently evidence of an inter-hemispheric coupling between the polar winter stratosphere and polar summer mesosphere has been presented using the mesospheric pole-to-pole circulation as the connecting link (Karlsson et al, 2007;Becker et al, 2004;Becker and Fritts, 2006;Karlsson et al, 2008). These studies suggest a stronger upwelling in the Northern Hemisphere polar summer mesosphere as compared to the Southern Hemisphere, accompanied by a stronger meridional flow towards the Southern Hemisphere winter polar region.…”

Section: Discussion and Summarymentioning

confidence: 86%

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

et al. 2008

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Abstract. Mesospheric water vapour measurements taken by the SMR instrument aboard the Odin satellite between 2002 and 2006 have been analysed with focus on the mesospheric semi-annual circulation in the tropical and subtropical region. This analysis provides the first complete picture of mesospheric SAO in water vapour, covering altitudes above 80 km where previous studies were limited. Our analysis shows a clear semi-annual variation in the water vapour distribution in the entire altitude range between 65 km and 100 km in the equatorial area. Maxima occur near the equinoxes below 75 km and around the solstices above 80 km. The phase reversal occurs in the small layer inbetween, consistent with the downward propagation of the mesospheric SAO in the zonal wind in this altitude range. The SAO amplitude exhibits a double peak structure in the equatorial region, with maxima at about 75 km and 81 km. The observed amplitudes show higher values than an earlier analysis based on UARS/HALOE data. The upper peak amplitude remains relatively constant with latitude. The lower peak amplitude decreases towards higher latitudes, but recovers in the Southern Hemisphere subtropics. On the other hand, the annual variation is much more prominent in the Northern Hemisphere subtropics. Furthermore, higher volume mixing ratios during summer and lower values during winter are observed in the Northern Hemisphere subtropics, as compared to the corresponding latitude range in the Southern Hemisphere.

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Section: Discussion and Summarymentioning

confidence: 86%

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

et al. 2008

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“…Karlsson et al (2009a) analyzed simulations from the Canadian Middle Atmosphere Model and found that the model reproduces the observed relationship. Karlsson et al (2007Karlsson et al ( , 2009b found a link between variability of PMCs and dynamical variations in the opposite (winter) hemisphere stratosphere. Espy et al (2011) found that the correlation varied with the phase of the QBO in tropical stratospheric zonal wind.…”

Section: Teleconnections Involving Zonal Mean Winds and Planetary Wavesmentioning

confidence: 99%

Global Dynamics of the MLT

2012

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The transition between the middle atmosphere and the thermosphere is known as the MLT region (for mesosphere and lower thermosphere). This area has some characteristics that set it apart from other regions of the atmosphere. Most notably, it is the altitude region with the lowest overall temperature and has the unique characteristic that the temperature is much lower in summer than in winter. The summer-to-winter-temperature gradient is the result of adiabatic cooling and warming associated with a vigorous circulation driven primarily by gravity waves. Tides and planetary waves also contribute to the circulation and to the large dynamical variability in the MLT. The past decade has seen much progress in describing and understanding the dynamics of the MLT and the interactions of dynamics with chemistry and radiation. This review describes recent observations and numerical modeling as they relate to understanding the dynamical processes that control the MLT and its variability. Results from the Whole Atmosphere Community Climate Model (WACCM), which is a comprehensive high-top general circulation model with interactive chemistry, are used to illustrate the dynamical processes. Selected observations from the Sounding the Atmosphere with Broadband Emission Radiometry (SABER) instrument are shown for comparison. WACCM simulations of MLT dynamics have some differences with observations. These differences and other questions and discrepancies described in recent papers point to a number of ongoing uncertainties about the MLT dynamical system.

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“…Liu and Roble 2002;Tan et al 2012;Yiğit and Medvedev 2012;Yuan et al 2012;Miyoshi et al 2015). The SSW impact can also extend into the summer mesosphere and mesopause region, as evidenced in observations and numerical simulations, through inter-hemispheric coupling (Becker and Fritts 2006;Karlsson et al 2007Karlsson et al , 2009aKörnich and Becker 2010;Tan et al 2012;Miyoshi et al 2015). Numerical simulations by Liu et al (2013Liu et al ( , 2014a and Miyoshi et al (2015) suggest that the SSW impact may extend into the upper thermosphere, though observations of thermospheric responses to SSW are less conclusive (Liu et al 2011;Fuller-Rowell et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Gravity Wave Variation from the Troposphere to the Lower Thermosphere during a Stratospheric Sudden Warming Event: A Case Study

Liu

2017

SOLA

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High resolution Whole Atmosphere Community Climate Model (WACCM) simulations are used to study how gravity waves vary during a stratospheric sudden warming (SSW) event from the source region to the lower thermosphere. The variation of zonal mean momentum flux of resolved gravity waves (with zonal wavelengths less than 1600 km) during SSW are qualitatively consistent with those obtained from parameterized studies, mainly caused by the change of filtering by the mean zonal wind. At high latitude in the winter hemisphere, stratospheric and mesospheric momentum fluxes vary rapidly during SSW, and their magnitudes decrease significantly following SSW, agreeing with satellite observations. Gravity waves are also found to vary as wave sources change. At tropical regions (especially in the summer hemisphere), convectively generated gravity waves increase due to enhanced deep convection following SSW. At higher latitudes, orographic waves vary during SSW as the wind changes extend from the stratosphere down into the troposphere. Gravity waves generated from adjustment of the polar jet also undergo significant changes during SSW. These changes lead to strong longitudinal variation of gravity waves.(Citation: Liu, H.-L, 2017: Gravity wave variation from the troposphere to the lower thermosphere during a stratospheric sudden warming event: A case study. SOLA, 13A, 24−30,

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Evidence for interhemispheric stratosphere‐mesosphere coupling derived from noctilucent cloud properties

Cited by 103 publications

References 21 publications

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

Observations of the mesospheric semi-annual oscillation (MSAO) in water vapour by Odin/SMR

Global Dynamics of the MLT

Gravity Wave Variation from the Troposphere to the Lower Thermosphere during a Stratospheric Sudden Warming Event: A Case Study

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