Simulated current and projected radiation balance of a High Arctic lake during the open water season

The Arctic is warming four times faster than the global average, with lake ice cover duration shortening, increasing the role of lakes within the regional radiation balance. Studying Arctic lakes is logistically difficult; through ice cover modelling with the Canadian Lake Ice Model we project simulated radiation balance changes for a typical small High Arctic Lake to 2100 using the 0.44° horizontal grid from CoOrdinated Regional climate Downscaling Experiment, Representative Concentration Pathway 8.5 scenario. The open water season is projected to extend 90–100 days longer than the current open water season. During the open water period, net longwave radiation is projected to increase by ∼0.4 Wm −2 per decade. Annually, net and shortwave radiation are projected to increase (∼1 and 1.3 Wm −2 per decade), and longwave radiation is projected to decrease (0.4 Wm −2 per decade). The projected trends show that the largest net shortwave radiation increases are expected to occur in May and June, whereas net longwave radiation is projected to have the largest decrease in July. The role of lakes in the regional energy balance is increasing because of the lengthening open water season through increases in lake evaporative losses and warmer water temperatures, which favour invasive species and will negatively impact cold-water fish and organisms that are well adapted to ice-covered conditions.