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Thermal versus dynamical tropopause in upper‐tropospheric balanced flow anomalies
Author(s) -
Wirth V.
Publication year - 2000
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.49712656215
Subject(s) - tropopause , anomaly (physics) , anticyclone , thermal wind , geology , thermal , potential vorticity , barotropic fluid , inversion (geology) , geophysics , troposphere , mechanics , atmospheric sciences , physics , vorticity , meteorology , climatology , vortex , wind speed , wind shear , geomorphology , structural basin , condensed matter physics
This paper systematically investigates differences between the thermal and the dynamical tropopause for upper‐tropospheric balanced flow anomalies. Idealized cyclonic and anticyclonic anomalies are considered, which are either axisymmetric or plane symmetric. Given a distribution of potential vorticity (PV), the inversion problem is solved numerically to obtain the corresponding balanced flow (i.e. wind and temperature). The control parameter is the aspect ratio of the PV anomaly, which governs the partitioning into a thermal and a dynamical anomaly. For PV anomalies of intermediate and tall aspect ratios, the location of the thermal tropopause differs significantly from the location of the dynamical tropopause. The thermal tropopause is rather indistinct for intermediate aspect ratios, while it is sharp and well defined for both tall and shallow anomalies. A barotropic deformation flow field superimposed on a plane symmetric anomaly induces an ageostrophic wind which modifies the static stability throughout the PV anomaly such that the thermal and dynamical tropopauses evolve differently. Recent observations concerning the correlation between the thermal and ozone tropopauses can be interpreted consistently in terms of the present results.