Noble gases measured on water bottle samples during METEOR cruise M91@en

Coastal upwelling regions as the research area of the Metor cruise M91 off Peru belong to the most productive regions of the world ocean. Oceanic upwelling velocities, however, are too small to be measured directly. We will thus exploite the deviations of the helium-3/helium-4 ratio from the atmospheric solubility equilibrium in the case of upwelling to infer the vertical velocities. This method has already been applied in the equatorial eastern Atlantic and the coastal region off Mauritania. The resulting vertical velocities will be compared with Ekman theory. In conjunction with other measurements perfomed during M91, the upwelling velocities can be used to estimate advective transport of heat, nutrients and climate relevant trace gases into the mixed layer. […]以秘鲁外海Metor航次M91的研究区域——沿岸上升流区——作为研究对象，该区域属于全球海洋中生产力最高的海域之一。然而海洋上升流的流速极为缓慢，难以直接测定。因此我们将借助上升流事件中氦-3（helium-3）与氦-4（helium-4）的比值偏离大气溶解平衡的特征，反演垂直流速。该方法已在赤道东大西洋及毛里塔尼亚沿岸海域得到应用。所得垂直流速将与埃克曼（Ekman）理论进行对比。结合M91航次期间开展的其他观测数据，我们可利用该上升流流速估算热、营养盐以及与气候相关的痕量气体向混合层的平流输送量。[…]