Predictability of the coupled troposphere-stratosphere system
2010 (English)In: Seminar on Predictability in the European and Atlantic regions from days to years., Reading, UK.: ECMWF , 2010Conference paper (Other academic)
Tropospheric predictability is typically limited to about 20 days due to the chaotic nature of weather. The tropospheric variability contains planetary waves which can propagate vertically into the winter stratosphere, where they break and drive a residual meridional circulation. For cases of exceptionally strong planetary wave activity, this circulation can induce a polar stratospheric warming and a subsequent downward propagation of the circulation anomaly to the troposphere. This process provides an increased predictability for the troposphere. The predictability is associated with the zonal mean zonal wind around 60ºN and the Northern Annular Mode, which tends to a negative phase after a stratospheric warming event. The negative Northern Annular Mode phase yields colder temperatures in Mid- and Northern Europe. Thus, the coupled troposphere-stratosphere system improves tropospheric predictability on monthly to seasonal time-scales. This article reviews briefly the observed phenomena, the current theoretical understanding, and the role for numerical weather prediction.
Place, publisher, year, edition, pages
Reading, UK.: ECMWF , 2010.
Troposphere-Stratosphere coupling, predictability
Research subject Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-54058OAI: oai:DiVA.org:su-54058DiVA: diva2:391871
ECMWF 2010 Annual Seminar, 6 - 9 September 2010