Comparisons of sea ice motion and deformation, and their responses to ice conditions and cyclonic activity in the western Arctic Ocean between two summers
Comparisons of sea ice motion and deformation, and their responses to ice conditions and cyclonic activity in the western Arctic Ocean between two summers
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DOI：
10.1016/j.coldregions.2019.102925
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发表时间：
2020-02
影响因子：
4.1
通讯作者：
R. Lei;Dawei Gui;P. Heil;J. Hutchings;M. Ding
中科院分区：
文献类型：
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作者：
R. Lei;Dawei Gui;P. Heil;J. Hutchings;M. Ding
分别在2014年和2016年8月中旬至9月下旬的季节过渡期间，对30和31个冰漂流者进行了测量，以表征北冰洋西部的海冰运动和变形。由于夏季海冰的力学行为较冬季更接近于自由漂移，且颗粒化程度更高，使得夏季海冰变形的扩散距离明显减小。夏末松散海冰变形与空间尺度的对数关系是冻结海冰的2.4-3.1倍。2007年至2016年夏末（8月至9月），北极的海冰紧密度在2014年（2016年）最高（最低）。沿着2016（2014）冰营的轨迹，8 - 9月的平均10米风速比1979-2016年的平均值大（小）20%（13%）。与2012年8月的北极大气旋相比，2016年夏季的气旋规模和强度相当，但持续时间更长。与2014年相比，2016年夏末较低的冰密度加上较强的气旋活动导致冰速增加和变形增强。与2014年夏末相比，2016年夏末的海冰更接近于自由漂移，导致漂移场的均匀性更高，冰风速比更大，变形场的多重分形、局部化和时空耦合更弱。2014年夏末的冰变形的本地化是在冷冻季节，因为高冰的紧凑性。2016年夏季增强的冰动力通过正反馈促进了冰融化和面积损失。
Measurements from 30 and 31 ice drifters during the seasonal transition from mid-August to late September of 2014 and 2016, respectively, were used to characterize sea ice motion and deformation in the western Arctic Ocean. The dispersion distance for the ice deformation in summer was markedly reduced because the mechanical behavior of sea ice in summer is closer to free drift and more granular compared to that in winter. For unconsolidated sea ice in late summer the logarithmic relationship between deformation and spatial scale is 2.4–3.1 times that for ice under freezing conditions. For 2007 to 2016 late summer (August – September) sea ice compactness in the Arctic was the highest (lowest) in 2014 (2016). Along the trajectories of the 2016 (2014) ice camp, the average 10-m wind speed in August–September was larger (smaller) than that averaged in 1979–2016 by 20% (13%). Relative to the great Arctic cyclone in August 2012, cyclones in summer 2016 had comparable sizes and intensity but with longer persistence. Lower ice compactness coupled with stronger cyclonic activity in late summer 2016 led to increased ice speed and enhanced deformation compared to 2014. Sea ice during late summer 2016 was closer to free drift, resulting in greater homogeneity of the drift field, a larger ice–wind speed ratio, as well as weaker multifractality, localization, and space–time coupling of the deformation field compared to late summer 2014. The localization of ice deformation in late summer 2014 was comparable to that obtained in the freezing season because of the high ice compactness. The enhanced ice dynamics in summer 2016 promoted ice melt and area loss via the positive albedo feedback.