【Title】Observations on the thermodynamic balance between floe and lead in the Arctic Ocean during Summer
【Abstract】Thermodynamic balance between a floe and a small lead in the Arctic Ocean has been observed during the ice-camp period in the third Chinese Arctic Research Expedition from 20 to 28 August, 2008. The field measurements include surface air temperature above the floe, albedo of the lead, seawater temperatures in the lead and under the floe, the lateral and bottom mass balance of the floe. The surface air temperature kept being sub-zero Celsius degree during the observation. Sea ice has begun its annual cycle of growth in response to autumn cooling. The surface of the lead was frozen-up by 23 August. From then onward, the albedo of the thin ice-covered lead was 0.46(±0.03), the vertical seawater-temperature gradient in the lead, as well as the seawater temperatures both in the lead and under the floe decreased gradually, while the oceanic heat under the ice approached to zero. By the end of the observation, the thickness of the investigated floe has reached its annual minimum, while the lateral of the floe was in the melt phase, with mean melt rate of 1.0(±0.3)cm/d during the measurement, responding to an equivalent latent heat flux of 19(±6) W/m2. The lateral melt of the floe showed the most significant contribution to the sea-ice mass balance when comparing with the surface and bottom mass balances of the floe for our investigated region by the end of August.