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 Much of the carbon dioxide in Earth's atmosphere goes south, literally. Researchers using new supercomputer models have described for the first time how the Southern Ocean sucks the greenhouse gas out of the air and then shuttles it into the deep sea far from the Antarctic. The findings should give climate scientists a better understanding of this critical component of Earth's carbon cycle.

 事实上，地球大气中的许多二氧化碳都飘到了南方。通过新型的超级计算机模拟，研究人员首次描述了南大洋是如何从空气中吸收二氧化碳、又是如何将其运往远离南极地区的深海的。该发现会帮助气候科学家更好地了解地球碳循环中的这一关键环节。

 The carbon dioxide (CO₂) emitted into the atmosphere ends up several places. Some is absorbed by green plants, which turn it into food. Some CO₂ remains in the atmosphere for thousands of years, where it absorbs solar radiation. And some eventually works its way into the oceans and exits the carbon cycle. Oceans capture CO₂ because wind-driven waves churn the surface, mixing the gas into the water. Then ocean currents carry the carbon into the deep sea and away from the atmosphere.

 二氧化碳释放在大气中之后有几个归宿：一些被绿色植物吸收，变成食物；一些继续留在大气中吸收太阳辐射，一呆就是几千年；还有一些最终进入海洋，脱离了碳循环。海洋能够捕获二氧化碳，因为由风驱动的海浪使海面翻腾起来，夹杂着二氧化碳进入海水中，然后洋流携带着二氧化碳进入深海，远远地脱离了大气。

 Scientists have known about this process for decades. They've also known that the Southern Ocean, which surrounds Antarctica and stretches to the tips of South America, Africa, and Australia, pulls in far more than its share of CO₂. The strong winds there blow almost continuously, making the region an excellent absorber of the gas. The Southern Ocean accounts for only about 6% of the world's ocean area, but scientists estimate that it absorbs as much as 40% of the CO₂ taken in by the seas. There's a mystery, however: The Southern Ocean retains only about 9% of the CO₂ it absorbs. What happens to the rest of it?

 科学家们了解这一过程已有几十年了，他们还了解南大洋卷入的二氧化碳比其理应吸收的二氧化碳要多得多。南大洋环绕着南极洲，一直延伸到南美洲、非洲和澳大利亚的南端，那里的强风几乎在不间断地吹着，使得该区域成为极为理想的二氧化碳吸收带。南大洋只占世界海洋面积的约6%，但是科学家们估计，在海洋吸收的二氧化碳中，南大洋吸收的二氧化碳占到多达40%。然而，尚存一个谜团：南大洋中只存留着所吸收二氧化碳的约9%，其余的二氧化碳去了哪里？

 The answer has proven elusive because the Southern Ocean's remoteness and severe weather have made it extremely difficult to collect the necessary data. Satellite sensors have helped, and now researchers have plugged satellite measurements--along with available surface readings on CO₂ absorption, wind patterns, and water currents in the Southern Ocean--into a new high-resolution supercomputer model. Using data for 2005 and 2006, the first years that included these satellite observations, the team was able to pinpoint the wind patterns and currents that distribute ocean CO₂. As the team reports in today's issue of Nature, instead of sinking in place, almost all of the CO₂ is carried away from the Antarctic and toward the subtropics--hence the missing CO₂ in the Southern Ocean.

 事实证明，答案不易找到。原因是，南大洋地理位置偏远，天气条件恶劣，要想搜集到必要的数据资料是极其困难的。卫星遥感器提供了帮助！现在，研究人员把卫星测量数据以及在地面上所测得的有关南大洋二氧化碳吸收、风型和洋流的数据，输入一台高分辨率超级计算机模型中。2005年和2006年是最初实施卫星观测的年份，研究小组利用这两年的数据可以确定分布海洋二氧化碳的风型和洋流流向。研究小组在今天出版的《自然》杂志上报道：二氧化碳并没有下沉到固定的位置，相反，几乎所有的二氧化碳都被洋流带走，从南极地区向亚热带地区流去。

 The researchers also found that "the atmosphere overlying the Southern Ocean is undergoing significant climate change," says oceanographer and lead author Takamitsu Ito, of Colorado State University, Fort Collins. It's possible, he says, that "changing the atmospheric wind pattern in the region could alter the rate at which the Southern Ocean absorbs CO₂," possibly reducing the ocean's ability to consume the gas and leading to further global warming.

 科林斯堡市科罗拉多州立大学的海洋学家、研究论文的第一作者伊藤隆光说：“研究人员还发现，南大洋上空的大气正在经历重大的气候变化。”他还说：“该地区大气风型的变化可能会改变南大洋吸收二氧化碳的速度，从而降低大洋消耗二氧化碳的能力，导致全球变暖的加剧。”

 Oceanographer Michael Follows of the Massachusetts Institute of Technology in Cambridge, says the finding is significant because it demonstrates the dominant role that wind-driven currents play in transporting and storing carbon in the Southern Ocean. And it "reinforces how important changes in Southern Hemisphere winds can be for Earth's carbon cycle and its climate," he says.

 剑桥市麻省理工学院的海洋学家迈克尔·福洛斯称：该发现具有重要意义，因为它展示了南大洋中由风驱动的洋流在碳输运和碳存储方面所起的作用。“而且该发现更加有力地说明：在南半球，风的变化对于地球的碳循环和气候来说会有多么重要，”他说。