Sea ice and snow characteristics from year-long transects at the MOSAiC Central Observatory
Sea ice and snow characteristics from year-long transects at the MOSAiC Central Observatory
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DOI：
10.1525/elementa.2022.00048
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发表时间：
2023-02-16
影响因子：
3.9
通讯作者：
Liston, Glen E.
中科院分区：
文献类型：
--
作者：
Itkin, Polona;Hendricks, Stefan;Liston, Glen E.
重复的样线已成为空间分布的冰雪厚度测量的支柱，这对于了解冰质量平衡至关重要。在这里，我们详细介绍了 2019-2020 年北极气候研究多学科漂流观测站 (MOSAiC) 的样线，这是在整个季节收集的首次此类测量结果。与历史类似断面相比，MOSAiC 的积雪较薄（平均深度约为 0.1-0.3 m），而海冰则为较厚的第一年冰（FYI）和第二年冰（SYI）。 SYI 有两种不同的类型：由大面积融化池覆盖的表面形成的相对较薄的水平冰，以及相对较厚的变形冰。在 SYI 层，一月份仍然可以检测到重新冻结的融化池的空间特征。入冬时，最薄的冰也有最薄的雪，薄冰（FYI 为 0.33 mmonth-1，之前积水的 SYI 为 0.24 mmonth-1）的冬季生长速度超过了厚冰（0.2mmonth-1）。到 1 月份，FYI 的模态冰厚度 (1.1 m) 比之前积水的 SYI (0.9 m) 更大。到 2 月份，所有 SYI 和 FYI 的模态厚度都变得难以区分，约为 1.4 m。 5 月份测量到的最大模态厚度为 1.7 m。横断面包括变形冰，四月份积雪量最大。水平冰上的剩余积雪以雪丘的形式表现出典型的空间异质性。雪和海冰的空间相关长度尺度范围为 20 至 40 m 或 60 至 90 m，具体取决于采样方向，这表明已知的雪丘各向异性也体现在海冰厚度的空间模式中。从 MOSAiC 样线获得的各种雪和冰厚度数据是模型和遥感产品开发的宝贵资源。
Repeated transects have become the backbone of spatially distributed ice and snow thickness measurements crucial for understanding of ice mass balance. Here we detail the transects at the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) 2019-2020, which represent the first such measurements collected across an entire season. Compared with similar historical transects, the snow at MOSAiC was thin (mean depths of approximately 0.1-0.3 m), while the sea ice was relatively thick first year ice (FYI) and second-year ice (SYI). SYI was of two distinct types: relatively thin level ice formed from surfaces with extensive melt pond cover, and relatively thick deformed ice. On level SYI, spatial signatures of refrozen melt ponds remained detectable in January. At the beginning of winter the thinnest ice also had the thinnest snow, with winter growth rates of thin ice (0.33 m month-1 for FYI, 0.24 m month-1 for previously ponded SYI) exceeding that of thick ice (0.2 m month-1). By January, FYI already had a greater modal ice thickness (1.1 m) than previously ponded SYI (0.9 m). By February, modal thickness of all SYI and FYI became indistinguishable at about 1.4 m. The largest modal thicknesses were measured in May at 1.7 m. Transects included deformed ice, where largest volumes of snow accumulated by April. The remaining snow on level ice exhibited typical spatial heterogeneity in the form of snow dunes. Spatial correlation length scales for snow and sea ice ranged from 20 to 40 m or 60 to 90 m, depending on the sampling direction, which suggests that the known anisotropy of snow dunes also manifests in spatial patterns in sea ice thickness. The diverse snow and ice thickness data obtained from the MOSAiC transects represent an invaluable resource for model and remote sensing product development.