Mechanisms controlling the heat budget of the North Sea are investigated based on a combination of satellite sea surface temperature measurements and numerical model simulations. Lateral heat fluxes across the shelf edge and into the Baltic Sea as well as vertical ocean‐atmosphere heat exchange are considered. A 3‐D variational (3DVAR) data assimilation (DA) scheme is applied, which contains assumed model error correlations that depend on the mixed layer depth derived from a coupled circulation/ocean wave model. The analysis balances pressure gradients introduced by temperature modifications. Significant hydrodynamic model response to DA was found, which should be considered in the heat budget estimations. The observed change of the current velocity field decreases the lateral advective volume/heat exchanges between the North Sea and the Atlantic, yielding an increased heat flux from the Atlantic into the North Sea and more heat flux from the sea to the atmosphere. The largest DA impact on volume/heat transport is in the Norwegian Channel, where the dominant process is Eulerian transport, followed by tidal pumping and wind pumping. Further analysis reveals an acceleration of the along‐shelf current at the northern edge of the North Sea, a decrease in the horizontal pressure gradient from the Atlantic to the North Sea, and a reduction of the Eulerian transport of volume/heat outward the North Sea. Furthermore, the coupling between the circulation model and the wave model has significant impacts on lateral heat advection in the DA run, which is due to the wave impact on the mixed layer depth.

中文翻译：

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卫星海面温度数据同化对北海海量和热量收支估计的影响

基于卫星海面温度测量和数值模型模拟的结合，研究了控制北海热量收支的机制。考虑了穿过架子边缘并进入波罗的海的横向热通量以及垂直的海洋-大气热交换。应用了3D变分（3DVAR）数据同化（DA）方案，其中包含假定的模型误差相关性，该相关性取决于从耦合环流/海浪模型得出的混合层深度。该分析平衡了温度修改所引入的压力梯度。发现了对DA的重要水动力模型响应，应在热预算估算中考虑这一点。观测到的当前速度场的变化减少了北海和大西洋之间的横向对流体积/热交换，从大西洋到北海的热通量增加，从海到大气的热通量增加。DA对体积/热传输的最大影响是在挪威海峡，其主要过程是欧拉运输，其次是潮汐抽水和风力抽水。进一步的分析表明，北海北部边缘的陆架流加速，从大西洋到北海的水平压力梯度减小，北欧向外的体积/热量欧拉输运减少。 。此外，由于波对混合层深度的影响，循环模型和波动模型之间的耦合对DA运行中的横向热对流有重要影响。