Importance of ocean salinity for climate and habitability
Importance of ocean salinity for climate and habitability
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DOI：
10.1073/pnas.1522034113
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发表时间：
2016-04-19
影响因子：
11.1
通讯作者：
Joshi, Manoj M.
中科院分区：
文献类型：
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作者：
Cullum, Jodie;Stevens, David P.;Joshi, Manoj M.
由于认识到海洋对气候的重要性，对太阳系外行星气候的模拟研究现在包括海洋环流的影响；事实上，地球上赤道至极地海洋热输送的峰值几乎是大气的一半。然而，这样的研究假设了基本的海洋性质，如盐度、温度和深度，与地球相似。这一假设导致了类似地球的环流：经向翻转，暖水在表面向极地移动，被冷却，在高纬度下沉，并在深处向赤道移动。这表明，不同盐度的行星际海洋可以沿着相反的方向循环：在表面向赤道方向流动的极地水，在热带下沉，并用温暖的水填满深海。这种不同的气流模式导致极地地区急剧变暖，这里使用了一个概念模型和一个海洋环流模型进行了演示。这些结果突出了海洋盐度对行星际气候和由此产生的宜居性的重要性，并需要在今后的研究中加以考虑。
Modeling studies of terrestrial extrasolar planetary climates are now including the effects of ocean circulation due to a recognition of the importance of oceans for climate; indeed, the peak equator-pole ocean heat transport on Earth peaks at almost half that of the atmosphere. However, such studies have made the assumption that fundamental oceanic properties, such as salinity, temperature, and depth, are similar to Earth. This assumption results in Earth- like circulations: a meridional overturning with warm water moving poleward at the surface, being cooled, sinking at high latitudes, and traveling equatorward at depth. Here it is shown that an exoplanetary ocean with a different salinity can circulate in the opposite direction: an equatorward flow of polar water at the surface, sinking in the tropics, and filling the deep ocean with warm water. This alternative flow regime results in a dramatic warming in the polar regions, demonstrated here using both a conceptual model and an ocean general circulation model. These results highlight the importance of ocean salinity for exoplanetary climate and consequent habitability and the need for its consideration in future studies.