Arctic Synoptic Basin-wide Oceanography.

看一张世界地图，找到设得兰群岛。沿北纬60度圆向东行驶。你穿过圣彼得堡，乌拉尔山脉，西伯利亚，白令海，阿拉斯加，加拿大北部，格陵兰的南端，然后回到设得兰。所有这些地方都是寒冷、恶劣的环境，特别是在冬天，除了设得兰群岛，那里潮湿多风，但全年相当温和。这是因为在英国，我们受益于被称为传送带的大西洋洋流向北带来的热量。这股洋流是由地表水推动的，北极及其周围的极端寒冷使地表水下沉。它在很深的地方通过大西洋向南返回。科学家们认为传送带可能会减速或停止，如果真的发生了，英国将变得更冷。我们知道地球在上个世纪或更长时间里一直在变暖，我们认为这是由于温室效应造成的。燃烧化石燃料会将大量二氧化碳排放到大气中，从而阻止热量离开地球，就像温室里的玻璃一样。在变暖的世界里，冰融化得更快，地球上有很多冰：格陵兰和南极洲的冰帽，北冰洋和南极的海冰，高山上的冰川。这会导致额外数量的淡水流入海洋。现在，这些淡水可能会影响传送带，因为它就像一个太轻而不能下沉的水的盖子，因此传送带停止。这种情况发生的可能性有多大？我们不知道，因为关于北冰洋是如何运作的，我们还有很多不了解的地方。你需要一艘强大的破冰船才能进入北冰洋，而这只在夏天才有可能，因为冬天海冰变厚，天气不好。世界各地的科学家都认为北冰洋很重要，因为它含有大量淡水，这就是为什么尽管在北极进行测量很困难，但他们决定在国际极地年期间加入他们的努力。北冰洋的淡水要么是(几乎)海冰形式的纯净淡水，要么是海洋顶部200米(大致)处的稀释海水。由于许多大河流入北极，北极的海水被冲淡了。在俄罗斯，最大的三条河流是叶尼塞河、莱纳河和奥布河；在阿拉斯加，麦肯齐河；还有许多较小的河流。北冰洋的淡水也来自其他来源：更多稀释的海水流经俄罗斯和阿拉斯加之间的白令海峡；夏天，冰盖略有融化，一些融化的水流入海洋；一些海冰直接融化到海洋中；当然，还会下雪。我们计划在许多国际合作伙伴的帮助下，在北冰洋周围进行一系列测量。我们想知道北冰洋现在有多少淡水。我们将使用破冰船进入北冰洋，并将对水的性质进行测量。我们还将在冰盖上部署仪器，在我们离开后提供数据，并分析卫星图像。所有这些数据将帮助我们了解北冰洋的现状，我们将使用海洋、冰盖和大气的数学模型来预测巡航之前、期间和之后的情况。通过测量溶解在海水中的少量化学物质，我们可以找出海水的来源。我们想知道这些淡水如何从北冰洋向南流入大西洋。它可能会采取什么路线？海洋对大气、河流流动和海冰有何反应？我们的目标是回答这些问题，以便其他试图预测未来几年或几十年地球气候的科学家知道如何在他们的预测模型中表示北冰洋。有了良好的预测，我们就可以为未来做计划。

Look at a map of the world and find the Shetland Islands. Follow the 60 degrees north latitude circle eastwards. You pass through St. Petersburg, the Ural Mountains, Siberia, the Bering Sea, Alaska, northern Canada, the southern tip of Greenland, then back to the Shetlands. All these places are cold, harsh environments, particularly in winter, except the Shetlands, which is wet and windy but quite mild all year. This is because in the UK we benefit from heat brought northwards by the Atlantic Ocean in a current called the Conveyor Belt. This current is driven by surface water being made to sink by the extreme cold in and around the Arctic. It returns southwards through the Atlantic at great depths. Scientists think it is possible that the Conveyor Belt could slow down or stop, and if it did, the UK would get much colder. We know the planet has been warming for the last century or more, and we think this is due to the Greenhouse Effect. Burning fossil fuels puts a lot of carbon dioxide into the atmosphere, which stops heat from leaving the Earth, like the glass in a greenhouse. In a warming world, ice melts faster, and there is a lot of ice on the Earth: ice caps on Greenland and Antarctica, sea ice in the Arctic and Antarctic Oceans, glaciers in high mountains. This causes extra amounts of fresh water to flow into the oceans. Now this fresh water can affect the Conveyor Belt by acting like a lid of water too light to sink, so the Conveyor Belt stops. What is the chance of this happening? We do not know, because there is much we do not understand about how the Arctic Ocean works. You need a powerful icebreaker to get into the Arctic Ocean, and that's only really possible in the summer, because in winter the sea ice thickens and the weather is bad. Scientists all over the world agree that the Arctic Ocean is important because it contains a lot of freshwater, which is why, although it is difficult to make measurements in the Arctic, they have decided to join their efforts during the International Polar Year. Fresh water in the Arctic Ocean is either (nearly) pure fresh water in the form of sea ice, or as diluted sea water in the top 200 metres (roughly) of the ocean. The sea water in the Arctic is diluted because many large rivers flow into it. In Russia, the three largest are the Yenisei, the Lena and the Ob; in Alaska, the MacKenzie; and there are many smaller rivers. Fresh water arrives in the Arctic Ocean from other sources as well: more diluted sea water flows through the Bering Strait, between Russia and Alaska; in summer, ice caps melt a little and some of the melt water runs into the ocean; some of the sea ice melts straight into the ocean; and (of course) it snows. We plan to conduct a set of measurements around the Arctic Ocean, with help from many international partners. We want to know how much fresh water is in the Arctic Ocean now. We will use an ice breaker to enter the Arctic Ocean and will make measurements of water properties. We will also deploy instruments onto the ice cover that will provide data once we've gone and will analyse satellite imagery. All of this data will help us understand the current state of the Arctic Ocean and we will use mathematical models of the ocean, ice cover, and atmosphere to predict conditions before, during, and after the cruise. By measuring small quantities of chemicals dissolved in the ocean waters, we can work out where the ocean water came from. We want to know how this fresh water might travel from the Arctic Ocean southwards into the Atlantic. What route might it take? How does the ocean respond to the atmosphere, to river flows and to sea ice? We aim to answer these questions so that other scientists who try to forecast the Earth's climate in the coming years and decades will know how to represent the Arctic Ocean in their forecast models. And with good forecasts, we can plan for the future.