Composite differences between negative and positive PDO-phases from the Natural CESM experiment.
Top Mean differences in sea level pressure (green contour lines) and geopotential heights in the middle stratosphere (50 hPa) on the northern hemisphere (colour shading) from 30°–90°N. Bottom Latitude-height sections for differences (left) in the E-P flux (arrows, indicating the direction of wave propagation) as well as its divergence (colour shading) and (right) in the residual mean meridional circulation (arrows, scaled with the square root of pressure, a direct diagnosis of meridional transport) and temperature differences (colour shading). The E-P flux and the residual mean meridional circulation are calculated from the Transformed Eulerian Mean (TEM) diagnostics40. Stippling indicates the 95% statistic significance level, with autocorrelation effects taken into account. Maps were produced using licensed IDL (http://www.harrisgeospatial.com/ProductsandSolutions/GeospatialProducts/IDL.aspx), version 8.1.