北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University;第70巻 第1号

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海面加熱で駆動される陸棚斜面湧昇流

堀尾, 一樹;磯田, 豊;小林, 直人;千葉, 彩

Permalink : http://hdl.handle.net/2115/79116
JaLCDOI : 10.14943/bull.fish.70.1.41
KEYWORDS : Shelf slope upwelling (SSU);Numerical model;Sea surface heating;Compensation flow

Abstract

If there is the coastal upwelling, it is common to think that the upward advection of cold deep water will make the coastal side cooler than the offshore side. Shelf slope upwelling (SSU) presented in this study, however, occurs only when the shallow coastal side is rather warm due to a continuous sea surface heating in summer. The present study investigated the formation process of such SSU using a numerical model driven by surface heating. From the results of examining unsteady state of heat budget and dynamic balance, SSU was found to be a kind of compensation flow, not the bottom Ekman flow. That is, to satisfy continuity in a vertical section, the offshore flow caused by the horizontal density/temperature gradient was supplemented by the shoreward flow strongly confined to the sloping seabed. This SSU will probably be one of the important flows contributing to material transport, e.g., unused nutrients and anoxic water etc., from deep to near coast in summer, while it is difficult to prove the existence of SSU even indirectly from the observed water temperature.

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