On the wind‐driven variability of the flow through Bering Strait
On the wind‐driven variability of the flow through Bering Strait
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DOI：
10.1029/jc090ic04p07213
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发表时间：
1985-07
影响因子：
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通讯作者：
K. Aagaard;A. T. Roach;J. Schumacher
中科院分区：
文献类型：
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作者：
K. Aagaard;A. T. Roach;J. Schumacher
对1981 ~ 1982年白令海峡附近的时间序列分析表明，白令海峡附近的纬向风分量、海流和洋面气压梯度有很好的相关性。我们认为，由于海岸几何形状的限制，有风驱动的流动发散扰动海洋压力场，占目前的变化。例如，偏北风会导致白令海峡东南部的海平面明显下降，如果风足够强，它们会使平均坡度反向向下穿过海峡。1976-1977年的风也与Coachman和Aagaard（1981）的白令海峡输送估计有很好的相关性，因此我们用1946 - 1982年的计算风来检验低频输送变率。存在明显的季节性周期，夏季运输量比冬季高出约50%。长期平均输运计算值小于0.6 Sv，远低于先前的估计值。在1948年至1967年的若干年中，明显出现了异常大的输送，但在过去的15年中，输送往往要少得多，这与这些年中较强的北风相对应。白令海峡附近风场的年际变率以及通过该海峡的输送的相应变率，实际上是北太平洋大气环流及其海洋效应的大尺度变率的一部分。
Analysis of time series from 1981 to 1982 near Bering Strait shows the meridional wind component, the current, and the oceanic pressure gradient to be well correlated. We argue that because of the constraining coastal geometry, there are wind-driven flow divergences which perturb the oceanic pressure field and account for most of the current variability. For example, northerly winds cause a pronounced set-down of sea level southeast of Bering Strait, and if the winds are strong enough, they will reverse the mean slope downward to the north through the strait. Winds during 1976–1977 were also well correlated with the Bering Strait transport estimates of Coachman and Aagaard (1981), and we therefore use the calculated winds from 1946 to 1982 to examine the low-frequency transport variability. There is a marked seasonal cycle, with summer transport about 50% greater than during winter. The long-term mean transport is calculated as less than 0.6 Sv, which is much lower than earlier estimates. Abnormally large transports apparently occurred during a number of years from 1948 to 1967, but during the past 15 years, transports have tended to be considerably less, corresponding to the stronger northerly winds during these years. The interannual wind variability near Bering Strait, together with the corresponding variability in the transport through the strait, is in fact part of the large-scale variability of the atmospheric circulation over the North Pacific and its oceanic effects.