Estimation of thermodynamic and dynamic contributions to sea ice growth in the Central Arctic using ICESat-2 and MOSAiC SIMBA buoy data
Estimation of thermodynamic and dynamic contributions to sea ice growth in the Central Arctic using ICESat-2 and MOSAiC SIMBA buoy data
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DOI：
10.1016/j.rse.2021.112730
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发表时间：
2021-12
影响因子：
13.5
通讯作者：
YoungHyun Koo;R. Lei;Yubing Cheng;B. Cheng;H. Xie;M. Hoppmann;N. Kurtz;S. Ackley;Alberto M. Mestas-Nuñez
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文献类型：
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作者：
YoungHyun Koo;R. Lei;Yubing Cheng;B. Cheng;H. Xie;M. Hoppmann;N. Kurtz;S. Ackley;Alberto M. Mestas-Nuñez
ICESat-2 （IS2）卫星高度计的精细空间分辨率可以监测海冰厚度的演变，并提供详细的动态信息（例如脊线和导线）。在这项研究中，我们首先评估了IS2在北冰洋中部冰生长季节估计冰的热力学生长和动态增厚的能力。在北极气候研究多学科漂流观测站（MOSAiC）考察期间，我们使用了10个热敏电阻串基海冰质量平衡阵列（SIMBA）浮标，在距离破冰船北极星号约50公里的尺度上进行了部署，作为热力学冰增长的指标。我们收集了距离单个浮标20公里缓冲距离内的IS2数据，并计算了IS2导出的冰厚的模态、中位数和平均值。IS2模态厚度与浮标冰厚偏差最小（- 0.169 m），代表水平冰厚。此外，IS2模态厚度的增加速率与冰的热力学增长速率接近，偏差较小，为−0.054 cm/d。但是，IS2的中值和平均厚度的增长速率分别大于热力冰的增长速率约0.114 cm/d和0.198 cm/d，因为它们还包括动力变形过程中厚度重分布引起的冰的增长。动态贡献分别占IS2中位厚度和平均厚度总增加量的26.1±10.3%和34.4±10.1%。在马赛克中心天文台半径约50 km范围内，IS2观测显示，脊分数从11月的<2%增加到3月的约4%（平均增加率约0.029%/d），脊高在同一时期增加了约0.047 cm/d。然而，铅的形成并没有显示出对动态冰增厚的显著贡献，因为铅是暂时的特征，只持续2-3天。尽管IS2冰厚估算和IS2浮标厚度比较存在相当大的不确定性，但本研究强调了IS2和SIMBA浮标结合测量来解释区域海冰质量平衡的重要性，并将热力贡献和动力贡献分开。
The fine spatial resolution of the ICESat-2 (IS2) satellite altimeter allows monitoring the evolution of sea ice thickness with detailed dynamic information (e.g. ridges and leads). In this study, we first assess the ability of IS2 to estimate thermodynamic ice growth and dynamic thickening during the ice-growing season in the central Arctic Ocean. As an indicator of the thermodynamic ice growth, we use 10 thermistor string-based sea ice mass balance array (SIMBA) buoys deployed at a scale of ~50 km from the Icebreaker Polarstern during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. We collect IS2 data within 20 km buffer distance from the individual buoys, and calculate the mode, median, and mean of the IS2-derived ice thickness. The IS2 modal thickness shows the least bias (−0.169 m) with the buoy ice thickness, representing level ice thickness. In addition, the increasing rate of the IS2 modal thickness is close to the thermodynamic ice growth with a small bias of −0.054 cm/day. However, the increasing rates of the IS2 median and mean thickness are greater than the thermodynamic ice growth by about 0.114 cm/day and 0.198 cm/day, respectively, because they also include ice growth caused by thickness redistribution during dynamic deformation. The dynamic contributions may account for 26.1 ± 10.3% and 34.4 ± 10.1% of the total increase of the IS2 median and mean thickness, respectively. Within a ~ 50 km radius area from the MOSAiC Central Observatory, IS2 measurements exhibit that the ridge fraction increased from <2% in November to ~4% in March (~0.029%/day of average increasing rate) and ridge height increased about 0.047 cm/day during the same period. However, lead formation does not show significant contributions to the dynamic ice thickening because leads are temporary features lasting only 2–3 days. Although there are considerable uncertainties in IS2 ice thickness estimation and IS2-buoy thickness comparison, this study emphasizes the importance of combining measurements by IS2 and SIMBA buoys to explain the regional sea ice mass balance with separating the thermodynamic and dynamic contributions.