A water mass history of the Southern California current system
A water mass history of the Southern California current system
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DOI：
10.1029/2019gl082685
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发表时间：
2019-06-28
影响因子：
5.2
通讯作者：
Jacox, Michael G.
中科院分区：
文献类型：
--
作者：
Bograd, Steven J.;Schroeder, Isaac D.;Jacox, Michael G.
加利福尼亚流系统代表了源自亚北极、亚热带和热带东太平洋的不同水团的汇合。它们相对影响的变化可以改变区域生物地球化学和生态系统结构。我们对历史水文数据进行了最优的多参数分析，以量化加利福尼亚流的水质量贡献的时空变异性。在斜斜内，主水团源区具有较强的跨岸梯度，反映了加利福尼亚流和加利福尼亚潜流内占优势的平流通道。厄尔尼诺-南方涛动赋予了源水相对贡献和深度结构的可变性，使得拉尼娜现象期间更强的上升流能够更有效地利用源自热带北太平洋东部的富营养、贫氧水域。这一区域水团史为理解加州洋流生物地球化学变异的驱动因素和途径提供了背景，并证明了发生在远场的海洋变化可能产生区域异质性影响。加州海流中的水来自海洋的不同部分：亚北极、亚热带和热带东太平洋。每一种水源都有自己的特征组合，比如温度、盐度、营养和氧气水平。这些水源相对贡献的变化可能影响当地条件，包括氧和营养成分含量以及上升水的性质。本文研究了来自南加州海域的长时间水文数据序列，以量化不同来源水团的相对贡献及其空间和年际变化。我们描述了受厄尔尼诺-南方涛动显著影响的空间非均质水团结构，对区域生物地球化学和生态系统结构具有重要意义。分析表明，加州海流的区域变化可以由远场发生的海洋变化驱动。
The California Current System represents a confluence of different water masses originating in the subarctic, subtropical, and tropical eastern Pacific. Variations in their relative influence can alter regional biogeochemistry and ecosystem structure. We perform an optimum multiparameter analysis on historical hydrographic data to quantify the spatiotemporal variability of water mass contributions to the California Current. Within the pycnocline, a strong cross-shore gradient in the primary water mass source reflects the dominant advective pathways within the California Current and California Undercurrent. The El Nino Southern Oscillation imparts variability in the relative contributions and depth structure of source waters, allowing stronger upwelling during La Nina to more effectively tap nutrient-rich, oxygen-poor waters originating in the eastern tropical North Pacific. This regional water mass history provides context for understanding the drivers and pathways of biogeochemical variability in the California Current and demonstrates that oceanic changes occurring far afield can have regionally heterogeneous impacts.Plain Language Summary Waters found in the California Current come from different parts of the ocean: the subarctic, subtropical, and tropical eastern Pacific. Each of these source waters has its own characteristic combination of properties like temperature, saltiness, and nutrient and oxygen levels. Variations in the relative contributions of these source waters can impact local conditions, including oxygen and nutrient content and the properties of upwelled waters. Here we explore long time series of hydrographic data from an oceanic region off southern California to quantify the relative contributions of different source water masses, and their spatial and interannual variability. We describe a spatially heterogeneous water mass structure which is significantly impacted by the El Nino-Southern Oscillation, with important implications for regional biogeochemistry and ecosystem structure. The analysis demonstrates that regional variability in the California Current can be driven by oceanic changes occurring far afield.