Structure and seasonality of interannual and interdecadal variability of the geopotential height and temperature fields in the Northern Hemisphere troposphere

Abstract

The long-term trend in the wintertime PNA-like pattern, with rising heights and temperatures over western Canada, has contributed substantially to the rather large rise in hemispheric-mean wintertime surface air temperature since the late 1970s but it has had little if any effect on the hemispheric mean temperature aloft, or on summertime surface air temperatures, which did not rise enough to completely offset the declines in the 1950s and early 1960s. -from Authors