Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain
Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain
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DOI：
10.1002/2014jc010327
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发表时间：
2015-03-01
影响因子：
3.6
通讯作者：
Gerdes, R.
中科院分区：
文献类型：
--
作者：
Hoppmann, M.;Nicolaus, M.;Gerdes, R.
冰架通过创造有利于冰下片状层形成的条件，与南极沿海海冰和相关生态系统发生强烈相互作用。由于后勤限制和缺乏合适的方法，对这种现象及其季节性演变的密切调查仍然是一个挑战。在这项研究中，我们描述了威德尔海东部埃克斯特罗姆冰架附近南极固定冰的季节性周期。我们使用了热敏电阻链，该热敏电阻链具有记录链中嵌入的电阻器循环加热引起的温度响应的附加功能。对 2012 年 11 月至 2014 年 2 月期间每天获得的垂直海冰温度和加热剖面进行分析，以确定海冰和雪的演变，并计算基础能量预算。残余热通量转化为片状层中的冰体积分数为 0.180.09，我们通过独立模型模拟重现了该分数，并且与之前的结果一致。手动钻探显示，第二年海冰下方的血小板层厚度平均每年增加至少 4 m，年最大厚度增加 10 m。在研究期间，海洋的贡献主导了海冰总产量，实际上占第二年海冰增长的 70%。夏季，21 W m(-2) 的海洋热通量导致片状层部分变薄。我们的结果进一步表明，与声学探测方法相比，主动加热方法非常适合在受海洋/冰架相互作用影响的区域推导固定冰质量平衡，因为它允许对血小板层厚度进行亚日监测。
Ice shelves strongly interact with coastal Antarctic sea ice and the associated ecosystem by creating conditions favorable to the formation of a sub-ice platelet layer. The close investigation of this phenomenon and its seasonal evolution remains a challenge due to logistical constraints and a lack of suitable methodology. In this study, we characterize the seasonal cycle of Antarctic fast ice adjacent to the Ekstrom Ice Shelf in the eastern Weddell Sea. We used a thermistor chain with the additional ability to record the temperature response induced by cyclic heating of resistors embedded in the chain. Vertical sea-ice temperature and heating profiles obtained daily between November 2012 and February 2014 were analyzed to determine sea-ice and snow evolution, and to calculate the basal energy budget. The residual heat flux translated into an ice-volume fraction in the platelet layer of 0.180.09, which we reproduced by a independent model simulation and agrees with earlier results. Manual drillings revealed an average annual platelet-layer thickness increase of at least 4 m, and an annual maximum thickness of 10 m beneath second-year sea ice. The oceanic contribution dominated the total sea-ice production during the study, effectively accounting for up to 70% of second-year sea-ice growth. In summer, an oceanic heat flux of 21 W m(-2) led to a partial thinning of the platelet layer. Our results further show that the active heating method, in contrast to the acoustic sounding approach, is well suited to derive the fast-ice mass balance in regions influenced by ocean/ice-shelf interaction, as it allows subdiurnal monitoring of the platelet-layer thickness.