Open AccessFriction in mid‐latitude cyclones: an Ekman‐ PV mechanism
Author(s) -
Boutle I. A.,
Belcher S. E.,
Plant R. S.
Publication year - 2014
Publication title -
atmospheric science letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.951
H-Index - 45
ISSN - 1530-261X
DOI - 10.1002/asl2.526
Subject(s) - baroclinity , ekman transport , ekman layer , anomaly (physics) , potential vorticity , middle latitudes , atmospheric sciences , boundary layer , environmental science , latitude , geology , meteorology , vorticity , climatology , vortex , mechanics , physics , oceanography , geodesy , condensed matter physics , upwelling
The mechanism by which the atmospheric boundary layer reduces the intensity of mid‐latitude cyclones is investigated. It is demonstrated that two alternative theories, Ekman pumping and the baroclinic potential vorticity ( PV ) mechanism, in fact act in union to maximize the spin‐down. Ekman pumping aids the ventilation of PV from the boundary layer, and shapes the resulting PV anomaly into one of increased static stability. PV inversion techniques are used to demonstrate how this anomaly reduces the coupling between the upper‐ and lower‐levels within the cyclone, reducing the growth rate.