2023-07-03 デラウェア大学 (UD)
◆国際研究チームは衛星観測を使用して、2003年から2020年までの沿岸植物プランクトンの増殖をマッピングし、その結果を「Nature」に発表しました。研究では、増殖が多く見られる地域や気候変動との関連性が示され、政策立案者や漁業管理に役立つ情報となることが期待されています。
＜関連情報＞
- https://www.udel.edu/udaily/2023/june/global-algal-blooms-yun-li-nature/
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JC017649
主要な西部境界海流に関連する隠れた湧昇システム Hidden Upwelling Systems Associated With Major Western Boundary Currents
Fanglou Liao, Xinfeng Liang, Yun Li, Michael Spall
Journal of Geophysical Research: Oceans Published: 03 March 2022
DOI:https://doi.org/10.1029/2021JC017649
Abstract
Western boundary currents (WBCs) play an essential role in regulating global climate. In contrast to their widely examined horizontal motions, less attention has been paid to vertical motions associated with WBCs. Here, we examine vertical motions associated with the major WBCs by analyzing vertical velocity from five ocean synthesis products and one eddy-resolving ocean simulation. These data reveal robust and intense subsurface upwelling systems, which are primarily along isopycnal surfaces, in five major subtropical WBC systems. These upwelling systems are part of basin-scale overturning circulations and are likely driven by meridional pressure gradients along the western boundary. Globally, the WBC upwelling contributes significantly to the vertical transport of water mass and ocean properties and is an essential yet overlooked branch of the global ocean circulation. In addition, the WBC upwelling intersects the oceanic euphotic and mixed layers, and thus likely plays an important role in ocean biological and chemical processes by transporting nutrients, carbon and other tracers vertically inside the ocean. This study calls for more research into the dynamics of the WBC upwelling and their role in the ocean and climate systems.
Key Points
- Intense upwelling systems exist along the major western boundary currents (WBC) around the global ocean
- The WBC upwelling is likely driven by the meridional pressure gradients along the western boundary
- The WBC upwelling contributes significantly to the vertical transport of water mass, ocean properties and materials around the global ocean
Plain Language Summary
This study shows that intense upwelling systems exist along the major western boundary currents (WBCs) around the global ocean. In contrast to other well-known oceanic upwelling systems (e.g., equatorial, coastal upwelling), these WBC upwelling systems, which are essential branches of the global ocean circulation, have been largely unrecognized in the literature. This intense upwelling and the associated overturning circulation in the subtropical ocean basins can transport nutrients, carbon, and heat inside the ocean, and consequently act as an important yet unexplored route through which the oceanic biological, chemical, and physical processes, and consequently the climate system, will be affected. This study calls for more research into the dynamics of the WBC upwelling and its role in the ocean and climate systems.
