基于冰基浮标数据的2018−2019年北极海冰运动特性时空变化分析

Analysis of spatiotemporal changes in Arctic sea ice motion characteristics in 2018−2019 using ice-based buoy data

海冰运动是影响北极海冰平流输运和物质平衡空间重新分布的重要因素。本研究基于2018年9月至2019年8月期间北冰洋66个冰基浮标位置记录数据,结合大气再分析数据,计算得到了海冰运动速度、冰速与风速的比值和海冰运动惯性强度,以刻画北极海冰运动学特征参数在一个冰季的时空变化,并讨论了不同区域冰速与风速比与海冰密集度的关联性。海冰漂移速度在波弗特–楚科奇海、东北极中央区和西北极中央区呈秋冬降低春夏升高的季节变化特征。格陵兰海月均海冰漂移速度((0.32±0.06)m/s)最大,其次是弗拉姆海峡((0.17±0.07)m/s)和波弗特–楚科奇海((0.14±0.05)m/s),而东北极中央区((0.09±0.02)m/s)和西北极中央区((0.07±0.03)m/s)较低。在月尺度上,冰漂移速度与风速的比值主要受海冰漂移速度支配。弗拉姆海峡和格陵兰海受较强的表层海流影响,冰速与风速比值较大,西北极中央区、东北极中央区和波弗特–楚科奇海的冰速与风速比值随着海冰密集度的增加趋近,并分布在0~0.02之间。所有浮标的月平均惯性运动指数为0.158±0.144,秋冬季过渡期间,海冰对风的响应以及海冰运动的惯性信号逐渐减弱,春–夏季随着海冰融化又开始增强,因此上述两个参数都可以作为指示海冰冰场固结程度的重要指标。

Sea ice motion is an important factor affecting Arctic sea ice advection and spatial redistribution of mass balance.Based on the data collected by 66 ice-based drifting buoys deployed in the Arctic Ocean from September 2018 to August 2019,combined with atmospheric reanalysis data and passive microwave sea ice concentration product,we calculated the sea ice drifting speed,the ice-wind speed ratio and the inertial intensity of sea ice mo-tion,so as to characterize the temporal and spatial changes of Arctic sea ice kinematic parameters over a full ice season,and analyse the correlation between ice-wind speed ratio and sea ice concentration.Seasonally,the sea ice drift speed in the Beaufort-Chukchi Sea,the central eastern Arctic Ocean and the central western Arctic Ocean showed a decreasing trend in autumn and winter and an increasing trend in spring and summer.Spatially,the Green-land Sea((0.32±0.06)m/s)had the highest sea ice drift speed,followed by the Fram Strait((0.17±0.07)m/s),and those in the Beaufort-Chukchi Sea((0.14±0.05)m/s),the central eastern Arctic Ocean((0.09±0.02)m/s)and the central western Arctic Ocean((0.07±0.03)m/s)were relatively low.On the monthly scale,the ice-wind speed ra-tio was mainly dominated by sea ice drift speed.The ice-wind speed ratio in the Fram Strait and the Greenland Sea was relatively larger,due to the strong ocean surface current.While the ice-wind speed ratio in the central western Arctic Ocean,the central eastern Arctic Ocean,and the Beaufort-Chukchi Sea was relative low and tended to be dis-tributed between 0-0.02 with the increase in sea ice concentration.The monthly averaged IMI for all buoys was 0.158±0.144,and the response of ice to wind and the inertial signal of ice motion gradually weakened during the autumn-winter transition and started to strengthen again in spring and summer.Therefore,both of the above para-meters can be used as important indicators to indicate the consolidation of ice field.