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The mass flux across the tropopause: Quasi‐geostrophic theory
Author(s) -
Juckes M. N.
Publication year - 1997
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712353703
Subject(s) - tropopause , baroclinity , potential vorticity , geostrophic wind , mean flow , troposphere , mass flux , atmospheric sciences , stratosphere , eddy , zonal flow (plasma) , flux (metallurgy) , physics , zonal and meridional , climatology , geology , vorticity , vortex , meteorology , mechanics , turbulence , plasma , materials science , quantum mechanics , metallurgy , tokamak
The mean meridional circulation in the troposphere is driven by eddy momentum fluxes associated with baroclinic waves. the dynamics of these waves can be described qualitatively by quasi‐geostrophic theory. Here, the flow in the vicinity of the storm tracks is modelled using f ‐plane quasi‐geostrophic theory with the tropopause represented as a nearly horizontal surface separating a troposphere of uniform potential vorticity from a similarly uniform stratosphere. Combining an analysis of the mean meridional mass‐flux associated with decaying eddies and the cross‐tropopause mass‐flux generated in the same process, it is possible to estimate the net flux both in the zonal mean and in a quasi‐Lagrangian mean framework. the quasi‐Lagrangian mean is here defined as an average along potential temperature contours on the tropopause. Consistent with earlier numerical and observational studies, it is found that the zonal mean mass‐flux is upwards poleward of the jet, whereas the quasi‐Lagrangian mean is downwards.