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| Titel |
Deducing changes in the extratropical storm tracks using Lagrangian diagnostics |
| VerfasserIn |
Lise Seland Graff, Joseph H. LaCasce |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081325
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| Zusammenfassung |
| The extratropical storm tracks are shifting meridionally in observations and in simulations of
the future climate. We investigate the storm-track response to warmer ocean surface
temperatures (SSTs) by imposing idealized heating patterns in an atmospheric general
circulation model with different fixed SST distributions. We conducted four simulations
where SSTs were increased by 2K in four different regions: at low-latitudes equatorward of
45°, at high-latitudes poleward of 45°, in the tropics equatorward of 15° and uniformly at all
latitudes. Additionally we cooled the ocean surface by 2K at latitudes poleward of 45 degrees
in one additional run.
We examine the resulting storm-track changes by using the Lagrangian tracking routine
TRACK (Hodges, 1995, 1999). We apply this routine to the relative vorticity field at the
850Â hPa surface in both hemispheres.
The results suggest that the storm-track position, genesis latitude and lysis latitude all
respond strongly both to low-latitude heating and to changes in the SST gradients. The
response is moreover sensitive to the location of the altered gradients. Significant changes are
also seen with other cyclone characteristics such as mean displacement, intensity and
lifetime. |
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