Direct observations of wave-sea ice interactions in the Antarctic Marginal Ice Zone

These are the data used in the analysis and creation of figures in S. Wahlgren, L.C. Biddle, J. Thomson and S. Swart: Direct observations of wave-sea ice interactions in the Antarctic Marginal Ice Zone [Submitted]. Preprint: https://doi.org/10.22541/essoar.168201718.84053333/v1 Abstract: Wave energy propagating into the Antarctic marginal ice zone affects the quality and extent of the sea ice, and wave propagation is therefore an important factor for understanding and predicting changes in sea ice cover. Sea ice is notoriously hard to model and in-situ observations of wave activity in the Antarctic marginal ice zone are scarce, due to the extreme conditions of the region. Here, we provide new in-situ data from two drifting Surface Wave Instrument Float with Tracking (SWIFT) buoys deployed in the Weddell Sea in the austral winter and spring in 2019. The buoy location ranges from open water to more than 200 km into the sea ice. We estimate the attenuation of swell with wave periods 8-18 s, and find an attenuation coefficient α = 4·10-6 to 7·10-5 m-1 in spring, and approximately five-fold larger in winter. The attenuation coefficients show a power law frequency dependence, with power coefficient 3.3 in spring and 4 in winter. The in-situ data also shows a change in wave direction, where wave direction tends to be more perpendicular to the ice edge farther into the sea ice. A possible explanation for this might be a change in the dispersion relation caused by changing sea ice composition. These observations can help shed further light on the influence of sea ice on waves propagating into the Marginal Ice Zone, aiding development of coupled wave-sea ice models. Related code: The accompanying code can be found at https://github.com/stinawahlgren/roammiz-wave-seaice-interactions. SWIFT buoy data has been processed using https://github.com/SASlabgroup/SWIFT-codes.

本数据集为S. Wahlgren、L.C. Biddle、J. Thomson与S. Swart在论文《南极边缘冰区（Antarctic Marginal Ice Zone）波-海冰相互作用直接观测》（已投稿）的分析与图件制作中所使用的数据。预印本链接：https://doi.org/10.22541/essoar.168201718.84053333/v1

摘要：传播进入南极边缘冰区的波浪能量会影响海冰的质量与分布范围，因此波浪传播是理解和预测海冰覆盖变化的关键因素。由于该区域环境极端严苛，海冰建模难度极高，且南极边缘冰区波浪活动的原位观测数据十分匮乏。本研究提供了2019年南半球冬、春季在威德尔海部署的两台带跟踪功能的表面波仪器浮标（Surface Wave Instrument Float with Tracking，SWIFT）的新型原位观测数据。浮标的观测覆盖范围从开阔水域延伸至深入海冰200余公里的区域。我们对周期为8~18秒的涌浪衰减情况进行了估算，结果显示春季的衰减系数α为4×10⁻⁶ 至7×10⁻⁵ m⁻¹，冬季的衰减系数约为春季的5倍。衰减系数呈现幂律频率依赖性，春季的幂指数为3.3，冬季为4。原位观测数据还显示了波浪方向的变化：越深入海冰区域，波浪方向越趋近于与冰边缘垂直。对此现象的一种可能解释是海冰组分变化引发了色散关系的改变。本观测结果有助于进一步阐明海冰对传入边缘冰区的波浪的影响，可为耦合波-海冰模型的开发提供支撑。

相关代码：配套代码可访问https://github.com/stinawahlgren/roammiz-wave-seaice-interactions获取。SWIFT浮标数据的处理使用了https://github.com/SASlabgroup/SWIFT-codes。