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Planetary‐scale disturbances in the polar winter stratosphere
Author(s) -
Simmons A. J.
Publication year - 1974
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.49710042309
Subject(s) - stratosphere , tropopause , atmospheric sciences , troposphere , zonal and meridional , sudden stratospheric warming , wind shear , geology , amplitude , geopotential , geopotential height , zonal flow (plasma) , climatology , perturbation (astronomy) , stratification (seeds) , environmental science , geophysics , physics , meteorology , polar vortex , wind speed , precipitation , plasma , quantum mechanics , tokamak , seed dormancy , germination , botany , dormancy , biology
Abstract Some models of steady planetary‐scale disturbances forced in the winter stratosphere by tropospheric pressure perturbations are presented for zonal flows with both vertical and meridional shear. The resulting structure of these disturbances is realistic. In particular, they are confined in the horizontal to regions of strong westerly wind, and do not exhibit a deficient vertical penetration, results in contrast with some earlier studies. Examples are included in which amplitudes are insensitive to the presence of either a strong New tonian cooling or singular‐line absorption. The time‐dependent behaviour of stratospheric planetary waves is examined for a zonal wind with uniform vertical shear. Analytical solutions emphasize the importance of a low‐level conversion of zonal available potential energy in amplifying a disturbance forced at the tropopause. When allowance is made for the meridional structure of the stratospheric jet, a reasonable agreement is obtained between theory and observation, in particular with respect to perturbation geopotential heights observed in sudden warmings.