Altimetric observation of wave attenuation through the Antarctic marginal ice zone using ICESat-2
Altimetric observation of wave attenuation through the Antarctic marginal ice zone using ICESat-2
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DOI：
10.5194/tc-16-2325-2022
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发表时间：
2022-06-16
期刊：
影响因子：
5.2
通讯作者：
Williams, Guy D.
中科院分区：
文献类型：
--
作者：
Brouwer, Jill;Fraser, Alexander D.;Williams, Guy D.
南极边缘冰带（MIZ）是一个高度动态的区域，海冰与南大洋无冰区产生的海面波相互作用。改进对MIZ范围和变率的大尺度（基于卫星的）估计对于了解大气-冰-海洋相互作用和生物过程以及探测其中的变化至关重要。定义MIZ的传统方法通常基于海冰浓度阈值，与驱动MIZ变异性的基本物理过程没有直接关系。为了解决这个问题，已经开发了新的技术，通过冰、云和陆地高程卫星-2 （ICESat-2）表面高度的变化来测量海冰中显著波高衰减的空间范围。向极波穿透极限（边界）定义为有效波高衰减等于有效波高估计误差的位置。由于ICESat-2数据受到严重云污染或未观察到波衰减，采用了广泛的自动和手动接受/拒绝标准，以确保沿轨道波穿透宽度估计的可信度。对2019年4个月（2月、5月、9月和12月）检索到的304条ICESat-2轨道的分析表明，海冰浓度得出的MIZ宽度估估值远低于本文提出的新技术的估估值（平均为7倍）。这些结果表明，基于海冰浓度估算MIZ的间接方法不足以表示定义MIZ的物理过程。在MIZ改进的波衰减大尺度测量将在增加我们对这一复杂海冰带的理解方面发挥重要作用。
The Antarctic marginal ice zone (MIZ) is a highly dynamic region where sea ice interacts with ocean surface waves generated in ice-free areas of the Southern Ocean. Improved large-scale (satellite-based) estimates of MIZ extent and variability are crucial for understanding atmosphere-ice-ocean interactions and biological processes and detection of change therein. Legacy methods for defining the MIZ are typically based on sea ice concentration thresholds and do not directly relate to the fundamental physical processes driving MIZ variability. To address this, new techniques have been developed to measure the spatial extent of significant wave height attenuation in sea ice from variations in Ice, Cloud and land Elevation Satellite-2 (ICESat-2) surface heights. The poleward wave penetration limit (boundary) is defined as the location where significant wave height attenuation equals the estimated error in significant wave height. Extensive automated and manual acceptance/rejection criteria are employed to ensure confidence in along-track wave penetration width estimates due to significant cloud contamination of ICESat-2 data or where wave attenuation is not observed. Analysis of 304 ICESat-2 tracks retrieved from four months of 2019 (February, May, September and December) reveals that sea-ice-concentration-derived MIZ width estimates are far narrower (by a factor of similar to 7 on average) than those from the new technique presented here. These results suggest that indirect methods of MIZ estimation based on sea ice concentration are insufficient for representing physical processes that define the MIZ. Improved large-scale measurements of wave attenuation in the MIZ will play an important role in increasing our understanding of this complex sea ice zone.