Over the past few years large-eddy simulation (LES) has demonstrated success in modelling continental radiation fog, and several recent studies have used LES to investigate the sensitivity of fog formation to physical processes such as turbulent mixing and surface heat and moisture exchange, as well as to the parametrization of microphysical processes such as cloud droplet activation. Here we extend these sensitivity studies to marine fog. There are several important differences in the formation of marine and continental fog, however moisture availability is no longer a decisive factor, and surface temperature changes over a much longer time scale. Here LES is used to examine the sensitivity of simulated marine-fog formation and maintenance to the cloud-droplet number concentration, turbulent mixing, and air–sea temperature difference. The strength of the fog (in terms of liquid water content) is found to be highly sensitive to all three factors. Varying only the cloud-droplet number concentration, even within a range of physically realistic values for marine regions, can mean the difference between fog halving or doubling in liquid water content. The sensitivities demonstrated herein indicate the great need and challenge for constraining these parameters in numerical weather prediction. Similarities and differences to the findings for continental radiation fog are examined, and important considerations for future improvements in marine-fog forecasting are discussed.

中文翻译：

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使用大涡模拟研究海洋雾对物理和微物理过程的敏感性

在过去几年中，大涡模拟 (LES) 在模拟大陆辐射雾方面取得了成功，最近的几项研究使用 LES 来研究雾形成对湍流混合和表面热湿交换等物理过程的敏感性，如以及微物理过程的参数化，例如云滴激活。在这里，我们将这些敏感性研究扩展到海洋雾。海洋和大陆雾的形成有几个重要差异，但水分可用性不再是决定性因素，表面温度在更长的时间范围内变化。在这里，LES 用于检查模拟海雾的形成和维持对云滴数浓度、湍流混合和海气温差的敏感性。发现雾的强度（就液态水含量而言）对所有三个因素都高度敏感。仅改变云滴数浓度，即使在海洋区域的物理现实值范围内，也可能意味着雾中液态水含量减半或加倍。这里展示的敏感性表明在数值天气预报中限制这些参数的巨大需求和挑战。研究了大陆辐射雾研究结果的异同，并讨论了未来改进海洋雾预测的重要考虑因素。即使在海洋区域的物理现实值范围内，也可能意味着液态水含量减半或加倍的差异。这里展示的敏感性表明在数值天气预报中限制这些参数的巨大需求和挑战。研究了大陆辐射雾研究结果的异同，并讨论了未来改进海洋雾预测的重要考虑因素。即使在海洋区域的物理现实值范围内，也可能意味着液态水含量减半或加倍的差异。这里展示的敏感性表明在数值天气预报中限制这些参数的巨大需求和挑战。研究了大陆辐射雾研究结果的异同，并讨论了未来改进海洋雾预测的重要考虑因素。