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contributor authorCavallo, Steven M.
contributor authorHakim, Gregory J.
date accessioned2017-06-09T17:29:31Z
date available2017-06-09T17:29:31Z
date copyright2012/05/01
date issued2012
identifier issn0027-0644
identifier otherams-86202.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4229735
description abstractropopause polar vortices (TPVs) are commonly observed, coherent circulation features of the Arctic with typical radii as large as approximately 800 km. Intensification of cyclonic TPVs has been shown to be dominated by infrared radiation. Here the hypothesis is tested that while radiation alone may not be essential for TPV genesis, radiation has a substantial impact on the long-term population characteristics of cyclonic TPVs.A numerical model is used to derive two 10-yr climatologies of TPVs for both winter and summer: a control climatology with radiative forcing and an experimental climatology with radiative forcing withheld. Results from the control climatology are first compared to those from the NCEP?NCAR reanalysis project (NNRP), which indicates sensitivity to both horizontal grid resolution and the use of polar filtering in the NNRP. Smaller horizontal grid resolution of 60 km in the current study yields sample-mean cyclonic TPV radii that are smaller by a factor of ~2 compared to NNRP, and vortex track densities in the vicinity of the North Pole are considerably larger compared to NNRP. The experimental climatologies show that winter (summer) vortex maximum amplitude is reduced by 22.3% (38.0%), with a net tendency to weaken without radiation. Moreover, while the number and lifetime of cyclonic TPVs change little in winter without radiation, the number decreases 12% and the mean lifetime decreases 19% during summer without radiation. These results suggest that dynamical processes are primarily responsible for the genesis of the vortices, and that radiation controls their maximum intensity and duration during summer, when the destructive effect of ambient shear is weaker.
publisherAmerican Meteorological Society
titleRadiative Impact on Tropopause Polar Vortices over the Arctic
typeJournal Paper
journal volume140
journal issue5
journal titleMonthly Weather Review
identifier doi10.1175/MWR-D-11-00182.1
journal fristpage1683
journal lastpage1702
treeMonthly Weather Review:;2012:;volume( 140 ):;issue: 005
contenttypeFulltext


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