Regional Signatures of the Annular Modes from the Surface to the Stratosphere

A sector-EOF analysis applied to the extratropical tropospheric circulation extracts robust circulation patterns that represent the regional signature of the annular modes. These regional patterns are eastward-propagating, long baroclinic-wave structures with the dipolar meridional structure in streamflow of the annular modes. The regional dipole patterns are also connected to the annular modes through their temporal correlation and their eddy flux signatures. These results serve to relate the hemispheric and the regional perspectives on the annular modes. The dipole patterns can be found throughout the year in the troposphere, but the wintertime signature of the patterns extends from the surface into the stratosphere. This suggests that these patterns represent a strongly vertically coupled mode that links stratospheric and surface-wind variability. A preliminary analysis of the signatures of these patterns in ocean- surface fields will be presented.