Figure 3. (left) Average near-surface air temperatures during the freezing season obtained from ERA-Interim T2M for the ice seasons of 1979–2014 and their linear trends (dashed red line), with red triangles denoting the operation years of the buoys.(right) Freezing degree days calculated at buoy sites using the average (6standard deviation) ERA-Interim T2M in 1979–2014 (black line and gray shading), ERA-Interim T2M obtained during the buoy operation years (red line), and nearsurface air temperature measured by the buoys (blue line).