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On the relationship between tropical moisture exports and extratropical cyclones

Knippertz, P. ORCID iD icon; Wernli, H.; Gläser, G.; Boleti, E.; Joos, H.; Binder, H.

Abstract (englisch):

Tropical moisture export (TME) events are an important element of the global circulation and contribute significantly to regional precipitation. They are defined here on the basis of trajectories starting in the tropical troposphere and reaching a water vapor flux of at least 100 g kg-1 m s-1 poleward of 35° latitude. TME frequency shows four marked occurrence maxima in both hemispheres with varying seasonal cycles. In some cases TMEs can be linked to similar phenomena of atmospheric flow such as Warm Conveyor Belts (WCBs) or Atmospheric Rivers (ARs). For example, 90% of all ARs affecting the US West Coast during December-May are connected to TME events, but the tropical moisture source is less important during the more active AR season June-November. In addition to these climatological TME characteristics we discuss two aspects of their relationship to extratropical cyclones: Case studies indicate that (i) cyclones traveling along the southern fringes of the midlatitude storm track can instigate the export of tropical moisture ahead of their cold fronts, and (ii) the tropical moisture can fuel latent heat release in the cyclone and therefore contribute to its intensification. ... mehr

Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Forschungsbereich Troposphäre (IMK-TRO)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Vortrag
Publikationsjahr 2016
Sprache Englisch
Identifikator KITopen-ID: 1000064996
HGF-Programm 12.01.02 (POF III, LK 01) Proc.res.f.multisc.predictab.of weather
Veranstaltung EGU General Assembly, 17–22 April 2016, Vienna, Austria
Bemerkung zur Veröffentlichung EGU2016-4385
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