SOME FEATURES OF THE TEMPERATURE REGIME OF THE ICE COVER IN ARCTIC SEAS DURING THE FIRST HALF OF SPRING

K. P. Tyshko and S. M. Kovalev

Field investigations in Kara and Laptev seas in the second half of April in different years have shown that the heating of the bottom ice layer with thickness 5–8 cm can be several tenths of a degree higher than the temperature of water surface. The most probable cause is the radiative heating of ice. The absorbtion of solar energy by the ice cover in this period, when most of its thickness is still rather cold, is more uniform than in May–June. The increase in air temperature stimulates the conductive heating of ice, which results in augmentation of the amount of air and saline inclusions in the upper and middle layers because of the activation of brine migration. These processes intensify the absorption of short-wave radiation and impede the heating of bottom ice carried. The results of calculations and comparison of vertical profiles of ice temperature formed in the presence and absence of the phenomenon considered support this hypothesis.