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dc.contributor.authorScott, R. K.
dc.contributor.authorSeviour, W. J. M.
dc.contributor.authorWaugh, D. W.
dc.identifier.citationScott , R K , Seviour , W J M & Waugh , D W 2020 , ' Forcing of the Martian polar annulus by Hadley cell transport and latent heating ' , Quarterly Journal of the Royal Meteorological Society , vol. Early View .
dc.identifier.otherPURE: 266359649
dc.identifier.otherPURE UUID: b9ae690a-ac1c-4074-8e69-b89b5ce15f94
dc.identifier.otherORCID: /0000-0001-5624-5128/work/74117883
dc.identifier.otherWOS: 000530430600001
dc.identifier.otherScopus: 85085149911
dc.description.abstractA hierarchy of idealized models is used to investigate the roles of Hadley cell forcing and latent heat release from carbon dioxide condensation in determining the annular potential vorticity structure of the Martian winter polar vortex. The angular momentum conserving the Hadley cell model of Lindzen and Hou with summer hemisphere heating maximum of appropriate strength and latitude produces a strong westerly jet near 60°N, which is similar in strength to the winter polar night jet on Mars. Although the corresponding potential vorticity profile in the angular momentum conserving and thermal wind regions has no annular structure resembling the Martian one, there is an implied δ‐function at the discontinuity in zonal wind. This δ‐function is smoothed out by explicit diffusion in full axisymmetric model integrations forming a partial annular structure, though a local maximum in potential vorticity at the pole persists and is further enhanced when cooling representing the polar night is included. A distinct polar minimum and clear annular potential vorticity structure are obtained, however, when an additional representation of polar latent heating is also included. Full eddy‐permitting shallow‐water model integrations confirm the basic structure obtained by the axisymmetric model and suggest a nominal value of viscosity appropriate as a representation of the effects of eddy mixing. Instability of the polar annulus leads to vacillation‐type behaviour involving eddy growth and annulus disruption, followed by re‐formation under the influence of radiative relaxation. The degree of transience and mean eddy activity both show an increase with stronger latent heating and the resulting deeper polar potential vorticity minimum, showing that mixing in polar regions may be dependent on details of polar carbon dioxide condensation. Vacillation time‐scales are also shown to vary with radiative time‐scales, but through a modification of instability growth rate rather than as a result of direct radiative restoration.
dc.relation.ispartofQuarterly Journal of the Royal Meteorological Societyen
dc.rightsCopyright © 2020 Royal Meteorological Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at
dc.subjectPolar vortexen
dc.subjectHadley cellen
dc.subjectPotential vorticityen
dc.subjectLatent heatingen
dc.subjectQA Mathematicsen
dc.subjectGE Environmental Sciencesen
dc.titleForcing of the Martian polar annulus by Hadley cell transport and latent heatingen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. Applied Mathematicsen
dc.description.statusPeer revieweden

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