Abstract
Sea-ice differs significantly in thickness, inner texture, thermal conductivity, snow-cover con
ditions, inner temperature gradient and so on according to its place of origin, consequently re
sulting in the great variability in inner heat flux. This work seeks to clarify the effect of the
above parameters on the heat conductive process through observations in the Sea of Okhotsk,
Lake Saroma, the Chukuchi Sea and the Arctic Gyre of the Arctic Ocean north to Canada.
The density and thermal conductivity of thicker sea-ice ike the Arctic sea-ice gradually in
crease from the bottom toward the surface,
and both parameters exhibit a positive correlation.
Sea-ice is more or less accompanied by snow cover everywhere. However, the inner tempera
ture of the upper ice layer is sensitive to the change in air temperature when the snow cover
is less than 20cm thick. However, the effects of changes in the air temperature is ameliorated
by snow cover, and the inner temperature does not exhibit a marked sensitivity when the snow
cover is thicker than 40cm.
The snow cover at all sites lacked uniform depth, but this fact is very significant in estimat
ing heat flux. We therefore observed the occurrence of snow-cover depth and derived a prob
ability density function that was applied to estimate the interface temperature between snowcover
and sea-ice. The heat flux of the sea-ice in the Chukchi Sea was finally estimesd to be
16% higher than that with a uniform depth of 20cm, the mean depth in the Chukchi Sea.
In order to estimate the heat flux correctly, we must know the heat process at the snow-cover
surface. We therefore compared an observation of surface temperature between a mercury ther
mometer and an infrared radiometer and discussed it in terms of the atmospheric stability. We
noticed that the latter exhibited 1.5°C lower temperature than the former, leading to the conclu
sion that the observation with the latter must be corrected by 1.5°C when used to construct an
atmospheric stability diagram.
