Interannual variability and ventilation timescales in the ocean cavity beneath Filchner‐Ronne Ice Shelf, Antarctica
Interannual variability and ventilation timescales in the ocean cavity beneath Filchner‐Ronne Ice Shelf, Antarctica
复制标题
南极洲菲尔希纳-龙冰架下洋腔的年际变化和通气时间尺度
DOI：
10.1029/2003jc002149
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发表时间：
2004
影响因子：
--
通讯作者：
S. Østerhus
中科院分区：
文献类型：
--
作者：
K. Nicholls;S. Østerhus
[1] 南极洲菲尔希纳-龙讷冰架下方的洋流和温度的多年时间序列显示了季节性和年际变化。季节性信号在所有测量地点都可见，尽管在 1997 年至 1998 年南方夏季期间，威德尔海南部的海冰覆盖量极少，导致异常大的高盐度陆架水脉冲冲入冰架下方，该信号在两年期间（1999 年至 2001 年）被淹没。在伯克纳岛海岸附近的一个仪器站点观察到该脉冲两次，一次是在前往菲尔奇纳凹陷的途中，一次是在信号围绕凹陷传播并以异常大的冰架水脉冲返回该地点之后。信号的计时可以估计冰下洋腔的冲刷时间尺度为 24 - 30 个月，这表明该腔对外部强迫具有高度响应性。根据冰架下条件恢复到原始状态所需的时间长度，得出了4-5年的空腔完全通风的时间尺度，这个时间尺度明显短于之前的估计。
[1] Multiyear time series of ocean current and temperatures from beneath Filchner-Ronne Ice Shelf, Antarctica, demonstrate both seasonal and interannual variability. The seasonal signal is visible at all measurement sites, although it was swamped for a 2-year period (1999 - 2001) when extraordinarily light sea-ice cover in the southern Weddell Sea during the 1997 - 1998 Austral summer caused an anomalously large pulse of High Salinity Shelf Water to flush beneath the ice shelf. The pulse was observed twice at an instrumented site near the Berkner Island coast, once on its way to the Filchner Depression and once after the signal had propagated around the depression and returned to the site as an anomalously large pulse of Ice Shelf Water. The timings of the signal allow an estimate of 24 - 30 months for the flushing timescales of the sub-ice shelf ocean cavity, indicating that the cavity is highly responsive to external forcing. A timescale for the full ventilation of the cavity of 4 - 5 years is obtained from the length of time the sub-ice shelf conditions take to return to their original state, a timescale significantly shorter than previous estimates.