Mass and volume transport variability in an eddy-filled ocean
Mass and volume transport variability in an eddy-filled ocean
复制标题
充满涡流的海洋中的质量和体积传输变化
DOI：
10.1038/ngeo126
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发表时间：
2008
影响因子：
18.3
通讯作者：
C. Wunsch
中科院分区：
文献类型：
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作者：
C. Wunsch
北大西洋的涡流活动在多年的时间尺度上造成全海洋体积输送的波动，约为每秒20×106立方米。这种背景噪音使得如果没有在三个空间维度上进行数十年的观测，就不可能探测到气候变化造成的海洋环流的可能趋势。海洋环流正在经历变化的可能性，作为主要气候变化的一部分或原因，正在进行激烈的讨论1，一些已发表的结果依赖于横跨北大西洋的系泊数据2，3。然而，循环非常嘈杂。在这里，我使用现有的估计的频率和波数含量的地转涡旋在ocean4表明，即使在没有一个真正的长期趋势的情况下，在整个海洋的综合运输的变化必须出现。预期的波动超过±20×109 kg s−1（或±20×106 m3 s−1），并显示多年的时间尺度。现有的知识的涡流场可以预测观测到的变化，并产生较低的界限（多年代际）的时间尺度需要检测到真正的趋势的大幅度。要探测和了解气候变化对海洋环流的影响，就需要进行长期的三维观测。
Eddy activity in the North Atlantic ocean produces fluctuations in ocean-wide volume transport on the order of 20×106 cubic metres per second, on multi-year timescales. Such background noise makes it impossible to detect possible trends in the ocean circulation due to a changing climate without multi-decadal observations in three spatial dimensions. The possibility that the oceanic general circulation is undergoing changes as part, or the cause, of major climate shifts is being intensely discussed1, with some published results relying on data from moorings spanning the North Atlantic Ocean2,3. The circulation is, however, extremely noisy. Here, I use existing estimates of the frequency and wavenumber content of geostrophic eddies in the ocean4 to show that variations in ocean-wide integrated transport must appear even in the absence of a true long-term trend. Expected fluctuations exceed ±20×109 kg s−1 (or ±20×106 m3 s−1) and exhibit multi-year timescales. Existing knowledge of the eddy field allows predictions of observed variability and produces lower bounds on the (multi-decadal) timescale required to detect true trends of a large magnitude. Detecting and understanding the effect of climate change on the ocean circulation requires observations in three dimensions over long periods of time.