Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation
The zonal mean state of the atmosphere in the Northern Hemisphere in winter is determined by the temperature at the Earth’s surface and by two potential vorticity (PV) anomalies (defined as that part of the PV field that induces a wind field) centred over the North Pole: one in the upper troposphere...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/200529 2023-07-23T04:17:40+02:00 Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation Hinssen, Y.B.L. van Delden, A.J. Opsteegh, J.D. de Geus, W. Marine and Atmospheric Research Sub Dynamics Meteorology Dep Natuurkunde 2010 application/pdf https://dspace.library.uu.nl/handle/1874/200529 en eng 0035-9009 https://dspace.library.uu.nl/handle/1874/200529 info:eu-repo/semantics/EmbargoedAccess Article 2010 ftunivutrecht 2023-07-01T23:48:23Z The zonal mean state of the atmosphere in the Northern Hemisphere in winter is determined by the temperature at the Earth’s surface and by two potential vorticity (PV) anomalies (defined as that part of the PV field that induces a wind field) centred over the North Pole: one in the upper troposphere/lower stratosphere (UTLS), extending to the Subtropics, and the other over the polar cap in the lower to middle stratosphere. Isentropic PV inversion demonstrates that the UTLS PV anomaly induces themain part of the zonalmean wind in the troposphere, including the subtropical jet stream, while the stratospheric PV anomaly induces the polar night stratospheric jet. The stratospheric PV anomaly has a greater amplitude and extends further downwards if the Arctic Oscillation (AO) index is positive. Also, the UTLS PV anomaly has a slightly larger amplitude if the AO index is positive, but the meridional PV gradient in the Subtropics that is associated with this anomaly is greatest when the AO index is negative, resulting in a stronger subtropical jet when the AO index is negative. PV inversion translates the UTLS PV anomaly into a wind anomaly and a static stability anomaly. The resulting differences in the vertical wind shear and in the Brunt–V¨ais¨al¨a frequency between the two AO phases show a larger baroclinicity in the extratropics when the AO index is positive. This explains why more extratropical cyclones are observed when the AO index is positive Article in Journal/Newspaper Arctic North Pole polar night Utrecht University Repository Arctic North Pole |
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Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
description |
The zonal mean state of the atmosphere in the Northern Hemisphere in winter is determined by the temperature at the Earth’s surface and by two potential vorticity (PV) anomalies (defined as that part of the PV field that induces a wind field) centred over the North Pole: one in the upper troposphere/lower stratosphere (UTLS), extending to the Subtropics, and the other over the polar cap in the lower to middle stratosphere. Isentropic PV inversion demonstrates that the UTLS PV anomaly induces themain part of the zonalmean wind in the troposphere, including the subtropical jet stream, while the stratospheric PV anomaly induces the polar night stratospheric jet. The stratospheric PV anomaly has a greater amplitude and extends further downwards if the Arctic Oscillation (AO) index is positive. Also, the UTLS PV anomaly has a slightly larger amplitude if the AO index is positive, but the meridional PV gradient in the Subtropics that is associated with this anomaly is greatest when the AO index is negative, resulting in a stronger subtropical jet when the AO index is negative. PV inversion translates the UTLS PV anomaly into a wind anomaly and a static stability anomaly. The resulting differences in the vertical wind shear and in the Brunt–V¨ais¨al¨a frequency between the two AO phases show a larger baroclinicity in the extratropics when the AO index is positive. This explains why more extratropical cyclones are observed when the AO index is positive |
author2 |
Marine and Atmospheric Research Sub Dynamics Meteorology Dep Natuurkunde |
format |
Article in Journal/Newspaper |
author |
Hinssen, Y.B.L. van Delden, A.J. Opsteegh, J.D. de Geus, W. |
spellingShingle |
Hinssen, Y.B.L. van Delden, A.J. Opsteegh, J.D. de Geus, W. Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
author_facet |
Hinssen, Y.B.L. van Delden, A.J. Opsteegh, J.D. de Geus, W. |
author_sort |
Hinssen, Y.B.L. |
title |
Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
title_short |
Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
title_full |
Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
title_fullStr |
Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
title_full_unstemmed |
Stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the Arctic Oscillation |
title_sort |
stratospheric impact on the troposphere deduced from potential vorticity inversion in relation to the arctic oscillation |
publishDate |
2010 |
url |
https://dspace.library.uu.nl/handle/1874/200529 |
geographic |
Arctic North Pole |
geographic_facet |
Arctic North Pole |
genre |
Arctic North Pole polar night |
genre_facet |
Arctic North Pole polar night |
op_relation |
0035-9009 https://dspace.library.uu.nl/handle/1874/200529 |
op_rights |
info:eu-repo/semantics/EmbargoedAccess |
_version_ |
1772179641589563392 |