Circulation in the Peruvian upwelling system near 15°S
Circulation in the Peruvian upwelling system near 15°S
复制标题
南纬 15° 附近秘鲁上升流系统的环流
DOI：
10.1029/jc085ic07p04036
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Robert L. Smith
中科院分区：
文献类型：
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作者：
K. Brink;D. Halpern;Robert L. Smith
在1977年3月至5月的海岸上升流生态系统分析联合II实验阶段，在秘鲁大陆架和南纬15°附近的斜坡上部署了密集的海流计、验潮仪和气象传感器阵列。在整个研究期间，低通滤波（频率<0.51 cpd）的当地风是向赤道方向的（有利于上升流），在陆架上方100米处的条件表明存在活跃的上升流环流。上升流事件（时间尺度为2-10天）在岸上速度和温度记录中显示得很清楚，但在沿岸速度中显示得很差。斜压、准地转自由沿岸俘获波在沿岸速度记录中占主导地位，并借助经验正交函数和其他技术研究了它们的动力学。根据海岸附近0.76 dyne cm−2的平均沿岸风应力计算出的近海埃克曼通量是根据陆架中部的近表层海流测量值计算出的通量的两倍多，但比在同一位置观测到的平均陆上流小27%。波动的质量和动量平衡也具有很强的三维性。沿岸速度分量趋于地转平衡。湍流效应在大陆架表面附近和底部附近都很重要，估计的边界层涡流粘度通常在40-60 cm 2 s-1之间。环流的三维性可能反映了当地风驱动和海底地形的复杂性。附录表格可与整个文章缩微胶片。来自美国地球物理联合会的订单，地址：2000佛罗里达大道，西北，华盛顿，华盛顿特区20009。J-80-008号文件，1美元。付款必须随订单一起进行。
During the March-May 1977 phase of the Coastal Upwelling Ecosystems Analysis Joint II experiment, an intensive array of current meters, tide gauges, and meteorological sensors was deployed over the Peruvian continental shelf and slope near 15°S. The low-pass-filtered (frequency <0.51 cpd) local winds were equatorward (upwelling favorable) throughout the study period, and conditions in the upper 100 m over the shelf indicated an active upwelling circulation. Upwelling events (with time scales 2–10 days) showed clearly in the onshore velocity and temperature records but poorly in the alongshore velocity. Baroclinic, quasi-geostrophic free coastal trapped waves dominated the alongshore velocity records, and their dynamics are investigated with the help of empirical orthogonal functions and other techniques. The offshore Ekman flux computed from the mean alongshore wind stress of 0.76 dyne cm−2 near the coast was more than twice as large as that computed from near-surface current measurements at midshelf but 27% smaller than the observed mean onshore flow at the same location. The fluctuating mass and momentum balances were also strongly three dimensional. The alongshore velocity component tended to be geostrophically balanced. Turbulent effects were important both near the surface and near the bottom over the shelf, where estimated eddy viscosities in the boundary layers were typically in the range of 40–60 cm2 s−1. The three dimensionality of the circulation probably reflects the complexity of the local wind driving and of the bottom topography. Appendix tables are available with entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, D.C. 20009. Document J-80-008; $1.00. Payment must accompany order.