The Interannual Variability of Sea Ice Area, Thickness, and Volume in the Southern Sea of Okhotsk and Its Likely Factors
The Interannual Variability of Sea Ice Area, Thickness, and Volume in the Southern Sea of Okhotsk and Its Likely Factors
复制标题
鄂霍次克南海海冰面积、厚度和体积的年际变化及其影响因素
DOI：
10.1029/2022jc019069
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Mitsudera Humio
中科院分区：
文献类型：
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作者：
Toyota Takenobu;Kimura Noriaki;Nishioka Jun;Ito Masato;Nomura Daiki;Mitsudera Humio
世界上纬度最低的海冰（不包括沿海冻结）位于鄂霍次克海南部（北纬46°以南），对淡水输入和初级生产有重大影响。这个地区受气候变化的影响，因此对海冰状况的监测很重要。然而，由于后勤方面的挑战，该地区海冰的年际变化知之甚少。1996-2020年期间，每年冬天都在该地区进行海冰观测。根据国际ASPeCt协议，结合卫星SSM/I‐SSMIS冰浓度数据（1988-2020），利用目视观测研究了冰情的年际变化及其可能的影响因素。分析了AMSR衍生的冰漂数据集和ERA5气象再分析数据集，以检验动力和热力学过程的影响。分析表明：(a)该地区的海冰面积与鄂霍次克海中部和北部不同，鄂霍次克海中部和北部的海冰面积呈减少趋势；(b)海冰体积具有显著的年际变化，海冰动态变形对峰值的影响远大于冰冻条件；(c)基于海冰流变学的剪切分量可以解释海冰显著变形的原因。这些结果表明，在数值海冰模式中纳入适当的海冰流变，以重现所有季节冰带的实际海冰体积和变形过程的重要性。
The lowest latitude sea ice in the world (excluding coastal freezing) is in the southern Sea of Okhotsk (south of 46°N), where it has significant impacts on freshwater input and primary production. This region is subject to climate change, and accordingly the monitoring of sea ice conditions is important. However, the interannual variability of the region's sea ice is poorly understood due to its logistical challenges. Sea ice observations have been conducted in this region every winter for the period 1996–2020. The interannual variability of the ice conditions and the likely factors responsible for it were investigated using visual observations following the international ASPeCt protocol, combined with satellite SSM/I‐SSMIS ice concentration data (1988–2020). AMSR‐derived ice drift data sets and ERA5 meteorological reanalysis data sets were also analyzed to examine the effects of dynamic and thermodynamic processes. Our analysis revealed that (a) sea ice area in this region varies differently from that in the central and northern Sea of Okhotsk, where decreasing trends are reported, (b) sea ice volume has remarkable interannual variation and the peaks appeared much to more affected by dynamically deformed ice than freezing conditions, and (c) prominently deformed ice can be explained by taking shear components into account based on sea ice rheology. These results suggest the importance of including the proper sea ice rheology in numerical sea ice models to reproduce the realistic sea ice volume and deformation processes, for all seasonal ice zones.