TY - JOUR
T1 - On the Upward Extension of the Polar Vortices Into the Mesosphere
AU - Harvey, V. Lynn
AU - Randall, Cora E.
AU - Goncharenko, Larisa
AU - Becker, Erich
AU - France, Jeff
N1 - Funding Information:
V. L. H. acknowledges support from the National Science Foundation (NSF) Coupling, Energetics, and Dynamics of Atmospheric Regions grant 1343031, NASA Living With a Star (LWS) grant NNX14AH54G, NASA Heliophysics Guest Investigator (HGI) grant NNX17AB80G, and travel support from the Stratospheric Processes and their Role in Climate (SPARC) Reanalysis Intercomparison Project (S-RIP). V. L. H. also thanks Doug Allen for useful discussions. L. P. G. is supported by NSF Division of Atmospheric and Geospace Sciences grant 1132267 and NASA LWS grant NNX13AI62G. J. A. F. acknowledges support from NASA HGI grant NNH15ZDA001N and the NASA Small Explorer Program through contract NAS5-03132. All of the data shown in this paper are publicly available. JRA-55 and ERA-Interim data were provided by the Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory at https://rda.ucar.edu/. CFSR/CFSv2 data were provided by Sean Davis at http:// ftpshare.al.noaa.gov. The processing of CSFR/CFsv2 output was funded by the NOAA HPC grant Climate Forecast System Reanalysis products for reanalysis validation and intercomparisons to NOAA ESRL CSD with the bulk of the work performed by Sean Davis, Jeremiah Sjoberg, and H. Leroy Miller. MLS v4.2 data are available from the NASA Goddard Space Flight Center for Earth Sciences Data and Information Services Center (DISC) at https://mls.jpl. nasa.gov/data/. MERRA and MERRA-2 data are available at MDISC, managed by the NASA Goddard Earth Sciences (GES) DISC at https://gmao.gsfc.nasa. gov/reanalysis/.
Funding Information:
V. L. H. acknowledges support from the National Science Foundation (NSF) Coupling, Energetics, and Dynamics of Atmospheric Regions grant 1343031, NASA Living With a Star (LWS) grant NNX14AH54G, NASA Heliophysics Guest Investigator (HGI) grant NNX17AB80G, and travel support from the Stratospheric Processes and their Role in Climate (SPARC) Reanalysis Intercomparison Project (S-RIP). V. L. H. also thanks Doug Allen for useful discussions. L. P. G. is supported by NSF Division of Atmospheric and Geospace Sciences grant 1132267 and NASA LWS grant NNX13AI62G. J. A. F. acknowledges support from NASA HGI grant NNH15ZDA001N and the NASA Small Explorer Program through contract NAS5-03132. All of the data shown in this paper are publicly available. JRA-55 and ERA-Interim data were provided by the Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory at https://rda.ucar.edu/. CFSR/CFSv2 data were provided by Sean Davis at http://ftpshare.al.noaa.gov. The processing of CSFR/CFsv2 output was funded by the NOAA HPC grant Climate Forecast System Reanalysis products for reanalysis validation and intercomparisons to NOAA ESRL CSD with the bulk of the work performed by Sean Davis, Jeremiah Sjoberg, and H. Leroy Miller. MLS v4.2 data are available from the NASA Goddard Space Flight Center for Earth Sciences Data and Information Services Center (DISC) at https://mls.jpl.nasa.gov/data/. MERRA and MERRA-2 data are available at MDISC, managed by the NASA Goddard Earth Sciences (GES) DISC at https://gmao.gsfc.nasa.gov/reanalysis/.
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/9/16
Y1 - 2018/9/16
N2 - 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.
AB - 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.
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U2 - 10.1029/2018JD028815
DO - 10.1029/2018JD028815
M3 - Article
AN - SCOPUS:85052968309
VL - 123
SP - 9171
EP - 9191
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 17
ER -