On the Upward Extension of the Polar Vortices Into the Mesosphere

V. Lynn Harvey, Cora E. Randall, Larisa Goncharenko, Erich Becker, Jeff France

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The polar vortices play a central role in vertically coupling the atmosphere from the ground to geospace by shaping the background wind field through which atmospheric waves propagate. This work extends the vertical range of previous polar vortex climatologies into the upper mesosphere. The mesospheric polar vortices are defined using the CO gradient method with Microwave Limb Sounder satellite data; the stratospheric polar vortices are defined using a stream function-based algorithm with data from meteorological reanalyses. Strengths and weaknesses of the two vortex definitions are given, as well as recommendations for when, where, and why to use each definition. Midwinter mean vortex geometry in the mesosphere is funnel shaped in the Arctic, with a wide top and narrow bottom. The Antarctic mesospheric vortex tapers with height in early winter and broadens with height in late winter. The seasonal evolution of mesospheric vortex frequency of occurrence, size, and zonal symmetry in both hemispheres is presented. Unexpected behavior above 60 km includes late season vortex broadening in both hemispheres, especially following winters without sudden stratospheric warmings. Following extreme stratospheric disturbances the polar night jet in the mesosphere strengthens and shifts poleward, resulting in a mesospheric vortex that contracts. Overall, the mesospheric polar vortices are more similar between the two hemispheres than their stratospheric counterparts. The vortex climatology presented here serves as an observational benchmark to which the mesospheric polar vortices in high-top climate models can be evaluated.

Original languageEnglish
Pages (from-to)9171-9191
Number of pages21
JournalJournal of Geophysical Research: Atmospheres
Volume123
Issue number17
DOIs
Publication statusPublished - Sep 16 2018

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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    Harvey, V. L., Randall, C. E., Goncharenko, L., Becker, E., & France, J. (2018). On the Upward Extension of the Polar Vortices Into the Mesosphere. Journal of Geophysical Research: Atmospheres, 123(17), 9171-9191. https://doi.org/10.1029/2018JD028815