Dynamical coupling of the lower and middle atmosphere historical background to current research

Hamilton, Kevin

doi:10.1016/s1364-6826(98)00118-7

Cited by 18 publications

(7 citation statements)

References 115 publications

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“…More detailed/analytical reviews of the middle atmospheric composition, thermal and dynamical structure, and associated wave activity may be found in the texts of Andrews et al [1987], Holton [1992], Salby [1996], and Brasseur and Solomon [1997], with more recent material presented by Holton et al [1995], Hamilton [1996], McLandress [1998], Hamilton [1999], Holton and Alexander [2000], and Fritts and Alexander [2003].…”

Section: A Conceptual Review Of the Middle Atmospherementioning

confidence: 99%

Mesosphere inversion layers and stratosphere temperature enhancements

Meriwether

Gerrard

2004

Reviews of Geophysics

124

155

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[1] It has been known for at least 30 years that vertically narrow thermal layers form within the middle atmosphere. Two types of temperature enhancements, the low-latitude to midlatitude mesosphere inversion layer (MIL) and the highlatitude winter stratosphere temperature enhancement (STE), have both received much attention within the atmospheric science community because of their unexplained formation mechanisms and potential impacts on the middle-atmosphere global circulation. Numerous experimental, numerical, and theoretical studies have attempted to explain certain aspects of these respective thermal layers, but no one theory consistently and satisfactorily describes all the features observed. We present a review of the literature and explicitly propose a classification scheme based on the different formation mechanisms suspected to cause these events. For the MIL we demonstrate that there are two subtypes. The first one is tidally driven and tends to occur above $85 km. This MIL originates from large-amplitude tidal waves propagating into the mesosphere and their subsequent nonlinear interactions with gravity waves, which can often create the appearance of a ''double MIL'' separated by approximately one vertical tidal wavelength ($25 km). The other subtype of MIL is formed by a climatological planetary wave dissipation mechanism that occurs at a zerowind line. The dissipation of the planetary wave tends to generate a mesoscale ($1000 km) inversion layer in the range of 65 -80 km. These two formation mechanisms explain a host of observed characteristics, including the reason behind the downward progression of some MILs and not others, the different climatological nature of the two forms of MIL events, and the relative scarcity of MIL observations at high latitudes. The STE is believed to be generated by an altogether different process, namely, the nonlinear interaction between the polar vortex and planetary waves/Aleutian High. The induced temperatures typically peak around 40 km and often exceed 300 K, generating what appears to be a ''low, hot stratopause.'' When vertical temperature profiles are combined with synoptic analyses, one observes that the STE is the consequence of high-latitude vortex interactions creating a baroclinic atmosphere, i.e., a downward adiabatic compression induced by an ageostropic flow. We summarize the details of the relationship between this feature and sudden stratospheric warmings, as well as the potential for in situ gravity wave generation. We close with a review of currently unexplained MIL/STE features and offer new directions for future middle-atmosphere thermal layer research.

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Section: A Conceptual Review Of the Middle Atmospherementioning

confidence: 99%

Mesosphere inversion layers and stratosphere temperature enhancements

Meriwether

Gerrard

2004

Reviews of Geophysics

124

155

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“…The general dynamics of the mesopause region (80-120 km) have been mathematically modelled and measured for many years and over long periods of time (Roble, 2000;Holton and Alexander, 2000;Forbes, 1995;Hamilton, 1999;Shepherd, 2000). Atmospheric parameters in this region such as wind velocity, temperature and airglow emission have been shown to have spatial and temporal wave-like features in them with a wide range of wavelengths, periods, amplitudes and phases.…”

Section: Introductionmentioning

confidence: 99%

Atomic oxygen annual and semi-annual variations in the mesopause region for mid and equatorial latitudes

Russell

Lowe

Ward

2004

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Thus to summarize, the McLandress, 1998; Hamilton, 1999]. Our review is aimed at combination of these studies over the past decade has produced summarizing the current state of our understanding of the MIL considerable progress in achieving a clear understanding of the regarding climatology and the various mechanisms that have been underlying thermal structure of the MLT region.…”

Section: Introductionmentioning

confidence: 99%

A review of the mesosphere inversion layer phenomenon

Meriwether¹,

Gardner²

2000

J. Geophys. Res.

107

110

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Abstract. An active topic of current research in aeronomy is the study of the dynamics of the mesosphere and lower thermosphere (MLT) from 60 to 130 km, especially in regard to the influences that govern variability. The physical processes of this region are diverse and complex with strong coupling between the MLT and the adjacent atmospheric regions brought about largely by the propagation and dissipation of atmospheric gravity waves (GWs) from sources above and below. The measurements of MLT winds and temperatures required for such studies represent daunting technical challenges. At low and midlatitudes the mesosphere inversion layer (MIL) phenomenon, a -• 10 km wide region of enhanced temperatures (AT-• 15-50K), is observed with great regularity in both the upper mesosphere (60-70 km) and the mesopause (90-100 km). Observations are largely based upon Rayleigh and Na temperature lidar systems but coherent radar observations have shown that the MIL phenomenon is linked to layers of turbulence occurring in both the topside and the bottomside regions. GW activity is believed to play an important role in the development of a linkage between the MIL and the tidal structure through GW coupling that results in an amplification of the tidal thermal structure. This linkage is readily evident for the upper MIL but is seen only occasionally for the lower MIL. Further study of MIL properties should emphasize continual 24 hour temperature observations, especially for the lower MIL region, to confirm the linkage of the development of the MIL to the MLT tidal structure.

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Dynamical coupling of the lower and middle atmosphere historical background to current research

Cited by 18 publications

References 115 publications

Mesosphere inversion layers and stratosphere temperature enhancements

Mesosphere inversion layers and stratosphere temperature enhancements

Atomic oxygen annual and semi-annual variations in the mesopause region for mid and equatorial latitudes

A review of the mesosphere inversion layer phenomenon

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