The Rio Grande Rise (RGR) is a plateau located at 31°S in the Southwestern Atlantic, rising from 5916m up to 161m below the sea level. The RGR is an important site for future mining of Fe-Mn crusts and can lead to an expansion of Brazil’s Exclusive Economic Zone. The Cruzeiro do Sul Rift (CSR) fault cuts through the RGR from southeast to northwest. In this study we characterize the RGR circulation, showing that M2 tides are the main source of variability in the region, with an amplitude that can reach 0.3ms, larger than the mean flow. These M2 tides are dominated by the baroclinic component and intensified near the bottom. The generation of M2 internal tides occurs mainly in the CSR slopes, with most energy converted from the barotropic tide being radiated away in the form of tidal beams. In addition, the impingement of the mean southern South Equatorial Current and tidal rectification generates anticyclonic circulations around the RGR peaks, with the latter mechanism being responsible for a bottom intensified anticyclonic circulation of 0.2ms. Finally, our results reveal that the RGR is a hotspot of internal tide generation in the Southwestern Atlantic.

中文翻译：

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格兰德海隆环流：西南大西洋内潮汐转换热点的动态


里奥格兰德隆起 (RGR) 是位于西南大西洋南纬 31° 的高原，海拔从海平面以下 5916m 上升至 161m。 RGR 是未来铁锰结壳开采的重要地点，可导致巴西专属经济区的扩张。南克鲁塞罗裂谷 (CSR) 断层从东南向西北穿过 RGR。在本研究中，我们对RGR环流进行了表征，表明M2潮汐是该地区变化的主要来源，其幅度可达0.3ms，大于平均流量。这些 M2 潮汐以斜压分量为主，并在底部附近增强。 M2内潮的产生主要发生在CSR斜坡上，正压潮汐转化的能量大部分以潮汐束的形式辐射出去。此外，平均南赤道流的冲击和潮汐整流在RGR峰值周围产生反气旋环流，后一种机制导致底部增强的反气旋环流为0.2ms。最后，我们的结果表明，RGR 是西南大西洋内潮汐产生的热点。