Resolving the regional signature of the annular modes

Abstract

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 the 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. © 2007 American Meteorological Society.