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Solid‐body rotation in the northern hemisphere summer stratosphere
Author(s) -
Piani C.,
Norton W. A.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016079
Subject(s) - stratosphere , baroclinity , barotropic fluid , atmospheric sciences , rotation (mathematics) , thermal wind , northern hemisphere , environmental science , physics , climatology , instability , meteorology , geology , mechanics , wind speed , wind shear , geometry , mathematics
The summer stratospheric flow is analysed in three years of ECMWF analyses. By diagnosing the angular rotation, it is shown that the summer stratospheric flow is close to solid‐body rotation for latitudes north of 30° with the rate of rotation increasing approximately linearly with height. This flow configuration is not in the radiatively determined state. The winds in thermal wind balance with the radiatively determined temperatures are unstable to barotropic/baroclinic instability. Small amplitude waves are diagnosed in the ECMWF analyses with periods of 5–10 days. These may drive the flow away from the radiatively determined state and lock the flow in the upper stratosphere into near solid‐body rotation.