CLIMATE SCIENCE: Enhanced: Already the Day After Tomorrow?
CLIMATE SCIENCE: Enhanced: Already the Day After Tomorrow?
复制标题
气候科学：增强：已经是后天了吗？
DOI：
10.1126/science.1100085
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发表时间：
2004
期刊：
影响因子：
56.9
通讯作者：
B. Hansen
中科院分区：
文献类型：
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作者：
B. Hansen
海洋温盐环流 (THC) 甚至已经引起了好莱坞的关注，成为了一个公共主题，这并非没有道理。 THC 有助于驱动全球洋流，对世界气候很重要（请参阅本页地图）。北大西洋的THC有可能在本世纪大幅减弱，这将对我们的气候产生令人不快的影响——不是灾难电影中的冰河时代，而是北欧部分地区的降温。 THC 是洋流的驱动机制。高纬度地区的冷却和结冰会增加地表水的密度，足以导致它们下沉。涉及几个不同的过程，统称为“通风”。当活跃时，通风可以持续向高纬度海洋深处供应浓密的海水。相比之下，在低纬度地区，垂直混合会加热深水并降低其密度。高纬度通风和低纬度混合共同在深海中形成水平密度差异，从而产生力。在北大西洋，这些力量帮助驱动北大西洋深水（NADW），为世界海洋的大部分深水提供水源。并非所有人都同意 THC 是 NADW 流的重要驱动机制。在深度观察到的南北密度差异可能是由水流产生的，而不是驱动它的 (1)。这个论点很诱人，但它忽略了真实海洋的一些显着特征，这些特征与许多概念、分析甚至一些数值模型不一致。格陵兰-苏格兰海岭将格陵兰-苏格兰海岭一分为二
With even Hollywood aroused, the thermohaline circulation (THC) of the ocean has become a public theme, and not without reason. The THC helps drive the ocean currents around the globe and is important to the world’s climate (see map on this page). There is a possibility that the North Atlantic THC may weaken substantially during this century, and this would have unpleasant effects on our climate—not a disaster-movie ice age, but perhaps a cooling over parts of northern Europe. The THC is a driving mechanism for ocean currents. Cooling and ice formation at high latitudes increase the density of surface waters sufficiently to cause them to sink. Several different processes are involved, which collectively are termed “ventilation.” When active, ventilation maintains a persistent supply of dense waters to the deep high-latitude oceans. At low latitudes, in contrast, vertical mixing heats the deep water and reduces its density. Together, high-latitude ventilation and low-latitude mixing build up horizontal density differences in the deep ocean, which generate forces. In the North Atlantic, these forces help drive the North Atlantic Deep Water (NADW) that supplies a large part of the deep waters of the world ocean.Not everybody agrees that the THC is an important driving mechanism for the NADW flow. The north-south density differences observed at depth might be generated by the flow rather than driving it (1). This argument is tempting, but it neglects some salient features of the real ocean that are at odds with many conceptual, analytical, and even some numerical models. The Greenland-Scotland Ridge splits the