Study Of Freeboard Change In Beaufort Sea Of Arctic Using CryoSat-2 Altimetry Data

Sea ice is one of the most important subjects in scientific research,and the change of sea ice is closely related to global climate change.Arctic sea ice is the most important and widely studied sea ice area in the world,act as the global cold source,it plays an important role in the global climate system.The dacades of the records and studies show that under the background of global warming and the frequency of extreme weather,Arctic sea ice coverage and thickness are reduced in the persistent,and also cause the temperature rise in Arctic and other climate change,the polar environment has also been seriously affected.The study also shows that the area of Arctic sea ice has occurred a record low for several times,such as the sea ice coverage of Arctic reach the minimum value in September 2007 and September 2010 since we have the satellite records and in 2017 January the Arctic sea ice volume break the lowest record,so it is very urgent to speed up the research on the Arctic sea ice.Due to the special geographical location and climatic conditions of the Arctic,the progress of research on the Arctic sea ice is relatively slow,many observation methods are unable to obtain the long time scale and wide area observation data in the Arctic which leads to the insufficient understanding of the overall situation and changes of Arctic sea ice.With the development of satellite altimetry technology,it is possible to make continuous observation of the Arctic sea ice.The CryoSat-2 is a specially designed altimetry satellite for polar sea ice measurement and the accuracy and the measuring range are significantly improved compared to the previous altimetry satellites.In this paper,the altimetry data from August 2010 to December 2013 of CryoSat-2 has been used to inverse the sea ice freeboard in Beaufort Sea in Arctic,and the results are used to validated with Upward Looking Sonar(ULS)data of Beaufort Gyre Exploration Project(BGEP).According to the results of sea ice freeboard inversion in the Beaufort Sea the sea ice freeboard distribution,variation trend of sea ice freeboard,the seasonal and interannual variations are analyzed.The results show that:1?Based on the freeboard distribution in each month we can conclude that the height of sea ice freeboard change with the latitude,the freeboard is larger in high latitude regions than that in low latitude regions.And the change rates of sea ice freeboard are not the same during the different sea area in Beaufort Sea.2?The average freeboard has obvious seasonal variation characteristics,from January to March are the winter of Arctic and the average freeboard stay in a growing state and reach the maximum in March.Then the sea ice start to melt form April to September and reach the minimum in September.The water begins to freeze in October and the average freeboard has returned to growth slowly and steadily,in December the average freeboard and the freeboard distribution are very close to that in January.3?The average sea ice freeboard in Beaufort Sea from August to December during 2010 to 2012 continue to decrease and in 2013 there is a rebound.The annual average height of Beaufort Sea ice freeboard has a decline from 2011 to 2012 and a rise in 2013.