30.05.2016: FB1-Seminar

11:00 h, Hörsaal, Düsternbrooker Weg 20

Abstract:

Previous studies showed that La Nina, the cold phase of ENSO, seems to have an influence on the North Atlantic/ European region. Own case studies are summed up in order to identify different Rossby wave trains which organized this far-field linkage for summer and winter.

During the summer 2010, Eastern Europe was affected by a long-persistent anticyclone. In the climatology, the summer blocking frequency is significantly increased under La Nina conditions.

We showed that multi-scale interference and interaction of Rossby waves are further responsible for the maintenance of the anticyclone and their impact on heavy rainfall over Northeast China in August.

The winter 2009 is characterized by an unexpected sudden stratospheric warming event under moderate La Nina conditions, which occur mainly due to the action of wave 2. The wave 2 induced eddy heat fluxes are extraordinary and directly connected with two amplifying anticyclones: over Alaska and over Scandinavia. From a climatological point of view, the Scandinavian anticyclone is also preconditioned and significantly connected with La Nina inducing both, together with the Alaskan ridge, a strong planetary Rossby wave 2. The role of the interference with the Madden Julian Oscillation is examined.

Present-day model simulations of ECHAM6-AMIP are compared with Reanalyses (ERA-Interim and MERRA) under the aspect of La Nina far-field impact over the North Atlantic/ European region during winter. Differences are examined.

<link service veranstaltungen wiss-veranstaltungen fb1-seminar internen link im aktuellen>Liste aller FB1 Seminarvorträge