Figure 4.2 Time series of annual mean ground temperature at depths of 9 to 26 m below the surface at selected measurement sites (see Figure 4.1 for locations) that fall roughly into the AACA priority regions: (a) cold continuous permafrost of northwestern North America (Beaufort-Chukchi region); (b) discontinuous permafrost in Alaska and northwestern Canada; (c) cold continuous permafrost of eastern and High Arctic Canada (Baffin Davis Strait); and (d) continuous to discontinuous permafrost in Scandinavia, Svalbard, Russia/Siberia (Barents region). Temperatures are measured at or near the level of zero annual amplitude. Data series are updated from Christiansen et al. (2010), Romanovsky et al. (2014, 2015) and Ednie and Smith (2015).