Study On Distribution And Variation Of Sea Ice In Arctic Summer Based On Shipboard Image Analysis

Against the backdrop of global warming,Arctic sea ice is rapidly melting.On the one hand,it has a major impact on the global climate system and local weather in the northern hemisphere,on the other hand,it also brings China the possibility of reasonable development of Arctic resources and the use of Arctic channels to develop shipping trade.The distribution of sea ice thickness and concentration in the Arctic in summer is an important basis to be considered for the opening of the channel and the design of polar navigation ships.Although satellite remote sensing is currently an important way to obtain large-scale Arctic sea ice thickness and concentration information,it still needs to be supplemented and verified by field observation data due to a series of factors.Therefore,ship-based observation methods and artificial observation methods were used to observe the sea ice thickness and concentration in the Arctic summer during the second to ninth Chinese National Arctic Research Expeditions from 2003 to2018.Based on ship-based observation data,this paper studies the temporal and spatial distribution of sea ice in the Arctic and Pacific sectors,and conducts comparison and verification with artificial observation data.The main conclusions are as follows:The summer ice thickness in the Pacific sector is mainly distributed in the interval of10-280cm.The distribution of sea ice thickness is approximately normal although differences exist between voyages.The average ice thickness decreases linearly with year by a gradient of1.5cm·a^-1.The decrease trend of ice thickness with year is not obvious in the sub-sea areas such as Chukchi Sea,Beaufort Sea,and Central Arctic Ocean.The sea ice thickness at different latitude with an interval of 2°is also approximately normally distributed.The average ice thickness increases linearly with latitude by a gradient of 1.3cm·deg^-1.In the sub-sea areas,the trend of the average ice thickness increasing with latitude in Central Arctic Ocean is the most significant.There is little difference between artificially observed ice thickness and ship-based ice thickness.The sea ice concentration of each voyage in the marginal ice area and dense ice area is mainly distributed in the range of 0-10%and 90%-100%respectively.The gradient of the average sea ice concentration in the dense ice area decreasing linearly with the year is 1.49%·a^-1,and the average sea ice concentration in the marginal ice area increases first and then decreases with the year.In the sub-sea areas,the sea ice concentration in Central Arctic Ocean is generally higher.The gradient of average sea ice concentration increasing linearly with latitude is 4.58%·deg^-1.The gradient of the average sea ice concentration increasing linearly with latitude in Beaufort Sea is higher than that in Central Arctic Ocean.The correlation between artificially observed sea ice concentration and ship-based sea ice concentration is relatively high,and artificially observed sea ice concentration is slightly higher.