Figure 2.

Time series of ice concentration (IC), sea surface temperature (SST), and net atmospheric surface heat flux (Q_net) at 71.5°N, 128°W during 2008 (green dot in Figure 1b). (a) IC from NT1 and that used by the OSTIA and CMC data sets (see section 2). Also shown are the Date of Opening (DOO; final date before the IC minimum when IC drops below 95%), the Date of Retreat (DOR; same as DOO, but for IC = 15%), and the Seasonal Loss of Ice Period, or SLIP = DOR – DOO, where these three quantities are defined using the NT1 data. IC = 95% and 15% are marked by dashed lines. (b) SST time series from OISST, OSTIA, and CMC, showing the Date of Maximum SST (DOM) when the SST_max is achieved (defined using OISST data). Also marked are 0°C (solid horizontal line) and −1.8°C (dashed horizontal line). (c) Net atmospheric surface heat flux Q_net from MERRA, showing the Date of maximum Q_net (DOQ) when Q_netmax is achieved, as well as the zero crossing dates DOX1 and DOX2 (Q_net = 0 marked with a solid horizontal line). All time series are smoothed with a running 15 day boxcar filter.