Downslope convection north of Elephant Island, Antarctica: Influence on deep waters and dependence on ENSO
Downslope convection north of Elephant Island, Antarctica: Influence on deep waters and dependence on ENSO
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南极洲象岛北部的下坡对流：对深水区的影响和对 ENSO 的依赖
DOI：
10.1029/2003gl017074
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发表时间：
2003
影响因子：
5.2
通讯作者：
P. Foden
中科院分区：
文献类型：
--
作者：
M. Meredith;C. Hughes;P. Foden
本文给出了南极半岛象岛以北陆坡1040m海温的长时间序列(1992-2001)。强烈的年度信号是显而易见的，南半球冬季期间或之后的最低温度，范围与邻近大陆架上较浅的水域相似。个别对流事件是可以观察到的大幅度冷峰，限于季节性最冷的温度时期。这些羽状物的密度足以季节性地取代环极深水，并将冷水直接注入深海。最冷的海水出现在1997/98年强烈的ENSO事件导致的异常海冰条件普遍存在的时候。因此，我们预计这种强对流事件会在ENSO时间尺度上重复发生。然而，观察到的半岛沿岸海冰的长期变暖和减少，可能会抑制这种让南大洋深处通风的模式。
We present a long time series (1992–2001) of bottom temperature from 1040m on the continental slope north of Elephant Island, Antarctic Peninsula. A strong annual signal is apparent, with minimum temperatures during or following the austral winter, and a range similar to that found in much shallower waters on the adjacent shelf. Individual convective events are observable as large‐amplitude cold spikes that are confined to the period of seasonally coldest temperatures. These plumes are dense enough to seasonally displace the Circumpolar Deep Water, and directly inject cold water into the deep open ocean. The coldest water occurred when anomalous sea ice conditions were prevalent, caused by the strong 1997/98 ENSO event. We thus expect repeats of such strong convective events on ENSO timescales. The observed long‐term warming and reduction in sea ice along the Peninsula may, however, act to suppress this mode of ventilating the deep Southern Ocean.