Abstract This work examines the seasonal thermohaline variability in the Gulf of Cadiz (SW Iberian Peninsula) based on 2009–2020 repeated hydrographic observations. Subsurface water types are assorted within the mixing triangle formed by Mediterranean and Eastern North Atlantic Central Waters (ENACW). A sharp interface between 400-500 m depth separates the saline Mediterranean Overflow Waters (MOW) from the ENACW salinity minimum siting atop. The water column is warmer and more saline in winter (cooler, fresher in summer). Maximum differences of up to 0.6 ∘C and 0.15 emanate from the ENACW/MOW interface. Changes appear related to the wind-driven seasonal alternation of vertical displacement of isopycnals and poleward-equatorward transports. Upwelling-favorable winds in summer steer positive Ekman pumping velocities, which seem responsible for cooling over the ENACW salinity minimum. Below, the warm, saline signal of subtropical waters from the Azores current is attenuated by the summer approach of cooler, fresher waters from the Portugal Current system. The change of sign of Ekman pumping in winter suggests subsidence of isopycnals and warming/salinification under the seasonal thermocline. Seasonal thermohaline changes of waters leaving the Mediterranean Sea are insufficient to explain the variations under the ENACW/MOW interface. Rather, variability of Atlantic waters entrained by the overflow seem to dictate these differences.

中文翻译：

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关于加的斯湾季节性温跃层以下水域的季节性

摘要 这项工作基于 2009-2020 年重复的水文观测，研究了加的斯湾（西南伊比利亚半岛）的季节性温盐变化。地下水类型在地中海和北大西洋东部中部水域 (ENACW) 形成的混合三角形内分类。400-500 m 深度之间的尖锐界面将盐水地中海溢流水域 (MOW) 与顶部的 ENACW 最低盐度选址分开。冬天水柱较暖，较咸（夏天较凉，较新鲜）。ENACW/MOW 接口发出的最大差异高达 0.6 ∘C 和 0.15。变化似乎与等密度线垂直位移和极地-赤道运输的风驱动季节性交替有关。夏季有利于上升流的风引导正的 Ekman 泵送速度，这似乎负责冷却超过 ENACW 盐度最小值。下面，来自亚速尔群岛洋流的亚热带水域温暖的咸水信号被葡萄牙洋流系统中较凉爽、较新鲜的水域夏季接近减弱。冬季 Ekman 抽水符号的变化表明在季节性温跃层下等密度沉降和变暖/盐化。离开地中海的海水的季节性温盐变化不足以解释 ENACW/MOW 界面下的变化。相反，溢出带来的大西洋水域的变化似乎决定了这些差异。冬季 Ekman 抽水符号的变化表明在季节性温跃层下等密度沉降和变暖/盐化。离开地中海的海水的季节性温盐变化不足以解释 ENACW/MOW 界面下的变化。相反，溢出带来的大西洋水域的变化似乎决定了这些差异。冬季 Ekman 抽水符号的变化表明在季节性温跃层下等密度沉降和变暖/盐化。离开地中海的海水的季节性温盐变化不足以解释 ENACW/MOW 界面下的变化。相反，溢出带来的大西洋水域的变化似乎决定了这些差异。