| Sea ice, which is one of the most important natural phenomena, sorely restricts the heat flux exchange between ocean and atmosphere. In the past decades, there are acutely change in sea ice area, thickness and the quantity of perennial ice during in the summer arctic. Especially in 2007 and 2008, the marginal ice line retreat to high latitude at Beaufort sea and there is no ice in some marginal ice zone(MIZ). At the same time, in the MIZ, shortwave radiation not only used to heat sea water and return to atmosphere in the form of long wave radiation but also used to the sea ice melting, which include lateral melting and bottom melting for the interaction between ocean and atmosphere. Also, in the MIZ the ocean have a special structure about temperature and salinity under sea ice. Especially, there have some special structures, which are subsurface warm water and weak vertical gradient in ocean salinity. These special structures exist in water depth of 15 to 40meter.In this article, a simple one-dimensional ocean-ice model is used to study the distribution of the shortwave radiation at the ocean and atmosphere in MIZ during summer time. The condition is shortwave radiation, cloud cover and the air temperature during 2007. The shortwave radiation, which is absorbed by ocean, is partitioned between lateral melting, bottom melting, temporary storage in the water and loss to the atmosphere. The percentage of heat flux which loss to the atmosphere in the shortwave radiation isn't affected by the change of sea ice, and it always takes up 9%. However, the others are affected by the originate sea ice area and those can change greatly to different sea ice. Large mount energy is obtained by the ocean. The energy exchange between ocean and atmosphere include latent heat, sensible heat and net long-wave radiation. Ocean obtained energy from the atmosphere in the form of latent and sensible because the air temperature higher than ocean temperature. Ocean release energy to the atmosphere in the form of net long-wave radiation. But the total energy is that the ocean loss energy in the form of long-wave radiation. When the ice scale is smaller the lateral melting is very important. And the percentage of heat flux, which used to ice lateral melt, become very important. However when ice scale is very big lateral heat flux can be ignored. There are two sources that can provide short wave radiation for ocean. They are the directly obtaining by ocean and coming from the sea ice. However, compared to the directly obtaining by ocean, the coming from the sea ice is very little, so the directly obtaining are the mainly source for the ocean heat. At same time, ice concentration is affected by the sea ice scale and there is little influence for ice thickness to different ice scale. So ice break play an important role during sea ice melt. And the difference of the ice thickness is caused by the sea ice bottom melting.In the MIZ, subsurface warm water and weak vertical gradient are special to this sea area. And the special structure is analyzed according to the ocean data which we obtained from the Third Chinese National Arctic Expedition. We also analyzed the reason why cause the subsurface warm and weak vertical gradient according to one-dimensional ocean-ice model. Percentage of shortwave radiation that temporary storage in the water is used to increase the temperature of mixed layer and sea water which located in 15 to 40 meter. So it is the most energy source to creating subsurface warmer waters. At same time, the maximum temperature and the position are affected by the sea ice scale, depth and concentration. Ice breaken degree is a good character to describe the sea ice scale. In this article the distribution of energy are considered in different sea ice area. The relationship between the distribution of energy and ice breaken degree are build up. And this relationship has good representative and has good practicality.
|
PDF Full Text Request