Upwelling shadows as nearshore retention sites: The example of northern Monterey Bay
Upwelling shadows as nearshore retention sites: The example of northern Monterey Bay
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DOI：
10.1016/s0278-4343(96)00045-3
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发表时间：
1997-04-01
影响因子：
2.3
通讯作者：
Largier, JL
中科院分区：
文献类型：
--
作者：
Graham, WM;Largier, JL
蒙特利湾北方温度升高的时期表明，这是一个在上升流活跃期间停留时间增加的区域。随着冷的上涌水平流进入海湾中心，近岸近表面温度的升高通常与近海温度的降低同时发生--温水和冷水的并置增强了被描述为“上涌阴影”的特征的热特征。我们提出了各种各样的数据收集1988年至1993年调用浅，分层，气旋环流在北方蒙特雷湾解释的上升流阴影作为一个动态响应上升流北部的海湾。与这种温暖的再循环相关的停留时间是8天的顺序，这是半封闭的海湾，而蒙特利湾是一个开放的海湾。我们估计上升流阴影水以0.083天（-1）的速率被近海水持续替换，我们建议环流速度为0.1米。s（-1），是需要产生的热特征给定的表面热通量在中央加州沿海地区的公开值。这个上升流阴影的热信号在上升流季节的大部分时间里都持续存在，在上升流中的短暂弛豫中幸存下来，但在一周或更长时间的长时间弛豫中分解。这一特征的分层和相干再循环对于生产力和幼虫的扩散和补充等生物过程可能非常重要。(C)1997 Elsevier Science Ltd.
Periods of elevated temperatures in northern Monterey Bay suggest that this is a region of increased residence time during periods of active upwelling. Nearshore increases in near-surface temperature often coincide with offshore decreases in temperature as cold, upwelled water is advected into the center of the bay-the juxtaposition of warm and cold water enhancing the thermal signature of a feature described as an 'upwelling shadow'. We present a variety of data collected from 1988 to 1993 invoking a shallow, stratified, cyclonic circulation in northern Monterey Bay to explain the upwelling shadow as a dynamic response to upwelling north of the bay. Residence times associated with this warm recirculation are of the order of 8 days which is comparable to semi-enclosed embayments whereas Monterey Bay is an open embayment. We estimate a continuous replacement of upwelling shadow water with offshore water at a rate of 0.083 day(-1), and we suggest that a circulation velocity of 0.1 m . s(-1), is needed to produce the thermal signature of the feature given published values of surface heat flux in the central California coastal region. The thermal signature of this upwelling shadow persists through much of the upwelling season, surviving brief relaxations in upwelling but breaking down during prolonged relaxations of the order of a week or longer. The stratification and coherent recirculation of this feature is likely to be very important for such biological processes as productivity and the dispersal and recruitment of larvae. (C) 1997 Elsevier Science Ltd.