Fig. 7
From: The different stratospheric influence on cold-extremes in Eurasia and North America
Regions and variables over which indices for CEN-analysis are calculated. a PCH: polar cap heights at 10 hPa northward of 60°N. b WAFS: eastern Siberian vertical wave-activity flux at 100 hPa calculated over the sector 50°N–75°N and 120°E–185°E. WAFC: same as WAFS but calculated over the Canadian longitudes 225°E–300°E. c Pac: geopotential heights at 500 hPa in the north Pacific calculated over the domain 50°N–70°N and 200°E–235°E (northern component of the WPO index)
