澳大利亚的这家公司专门储存空气 This company in Australia specializes in storing air

澳大利亚的这家公司专门储存空气 This company in Australia specializes in storing air.
Every few months, a team from the Australian Government science agency, CSIRO, and the Australian Bureau of Meteorology will bottle up air from here, at the northern tip of Tasmania, and send it off to be archived.
每隔几个月，澳大利亚联邦科学与工业研究组织（CSIRO）与澳大利亚气象局的团队就会在塔斯马尼亚最北端采集空气样本，然后将其密封保存，并送往档案馆。
A few days ago, back on the Australian mainland, in a suburb of Melbourne, I interviewed one of the team at the Air Archive to explain how and why.
就在几天前，在墨尔本的一个郊区，我对空气档案团队中的一位成员进行了采访，询问了他们采集及保存空气样本的具体做法和原因。
The first tank was taken on the 26th of April, 1978.
首个样本罐收集于1978年4月26日。
All up, we have close to 200 tanks spanning almost 50 years.
到目前为止，我们总共收集了大约200个样本罐，跨越了将近50年的历史。
The pressure they get to is around about 900 PSI.
这些罐子所承受的压力大致为900 磅/平方英寸。
They're 34 liter tanks, which means they hold around 2,000 liters of air once they're completely full.
这些气罐的容量为34升，满载时大约能够装下2000升空气。
This place, Kennaook Cape Grim, has the cleanest air in the world. When the wind's blowing from the south-west, when that air has traveled thousands of kilometers across the Southern Ocean without touching land.
这里，肯诺克格林角，每当西南风经过数千公里的南大洋无尽航行后抵达此处，未曾接触过任何陆地，我们便能拥有世界上最为洁净的空气。
So that is a monitoring station, testing the levels of dozens of gases and chemicals in the atmosphere.
所以这里是一个监测点，负责检测大气中数十种气体和化学成分的含量。
When we say clean air or baseline air, we mean that it has not had recent contact with land or pollution sources.
我们所说的洁净空气或基准空气，是指这些空气近期没有与陆地或任何污染源发生过接触。
We know that it's very representative of the mid-latitudes of the Southern Hemisphere background air.
我们了解到，这里监测到的空气能充分反映南半球中纬度区域的基础空气状况。
Most of the sources of the major greenhouse gases are in the northern hemisphere because that's where the major population centers are.
因为主要的人口聚集地位于北半球，所以该地区也是大多数主要温室气体的排放源。
It takes about a year to do the inter-hemispheric transport, going across the equator is much, much slower than the mixing within a hemisphere itself.
半球间的大气输送大概需要一年时间完成，而这一过程跨越赤道要缓慢得多，与同一半球内部的气体混合相比，速度相差甚远。
We wait until the wind is coming from the southwest direction, and normally we wait several hours.
我们会等待西南风开始吹拂，这通常需要耐心等上几小时。
Today, the wind is not blowing in the right direction!
今天风并没有从正确的方向吹来！
It's blowing in from the cities in Tasmania and the Australian mainland, but the team here are going to do a "practice fill" of an archive cylinder, so they can show you what would happen.
风正从塔斯马尼亚和澳洲大陆的城市吹过来，但是团队决定对一个档案气瓶进行实操练习，以便向您展示实际操作情况。
And it's a really technical operation that has to avoid contamination.
这项操作技术性很强，必须确保过程中严防污染。
These cylinders are filled cryogenically, under vacuum.
这些气瓶是通过真空低温技术进行充气的。
When they're put into the liquid nitrogen, the air naturally will be sucked into the tanks over a two-to three-hour period.
将气瓶置入液氮后，空气会在二至三小时的时间里自然流入罐中。
As any gas cools down, it compresses.
任何气体在冷却过程中都会发生压缩。
So initially the air rushes in to fill the vacuum, but then it hits liquid nitrogen-chilled stainless steel, so it cools and compresses and more air rushes in, which cool and compresses, and so on, and so on and so on.
因此，一开始空气会急速涌入以填补真空空间，但接着它会接触到被液氮冷却的不锈钢表面，使得空气迅速冷却并压缩，这样一来，又有新的空气继续涌入并冷却压缩，如此循环往复。
It's a really clever way to fill a pressurized canister without pumps.
这是个巧妙的办法，无需泵就能给气压罐充气。
We then let it heat up or warm up, and then we blast whatever water is in there out.
接下来，我们让气体回暖，随后将罐内的水分强力排出。
There is water in the tanks because there's water in the atmosphere, and we don't do any drying.
罐内之所以有水分，是因为大气中本就含水，而我们并未采取干燥措施。
We don't want to use pumps or any particular drying agent or method, as this can potentially contaminate the tanks.
我们不打算使用泵或任何特殊的干燥剂或干燥方法，以避免潜在污染储罐。
So I had an obvious question: how do they know that the air in the archive tanks doesn't change over time, through some chemical reaction, or osmosis through a faulty valve, or microbe contamination?
因此，我产生了一个明显的疑问：他们怎么能确信档案储罐里的空气不会随时间改变，不会因某些化学反应、阀门故障导致的渗透，或者微生物的污染而变化呢？
We take measurements of the archive regularly, maybe once a year we'll "take a sniff" out of each of the cylinders, so to speak, to ensure trace gases are not drifting or changing.
我们会定期对储藏罐进行检测，大约每年对每个气瓶进行一次象征性的“嗅测”，以此确保微量气体没有发生漂移或变化。
There is a little bit of moisture and water in there and has been concerns where the microbes might be changing the composition for some trace gases.
储罐中存在着少量的水分和水汽，有人担忧微生物可能会影响某些微量气体成分的稳定性。
But from what we've discovered so far, that's not really the case.
不过，根据我们目前的发现，实际情况并没有这个问题。
So they've got an archive.
因此，他们建立了一个档案库。
What do they do with it?
他们怎么利用这个档案库呢？
Well, let's say someone discovers that actually, there's a greenhouse gas or some other contaminant that we should have been testing for, for the last 50 years or so.
嗯，比如有人发现，其实在过去大约五十年里，有一种温室气体或是其他污染物质，我们本应该对它进行检测的。
The researchers can go to the archive, pull samples from the tanks, and use modern equipment to test old air.
研究人员能够前往这个档案库中，从储气罐里提取样本，并利用现代仪器对往年的空气样本进行检测。
Remember CFCs? They've been testing for those on site here for years, but it turns out the replacements also cause problems.
你还记得氯氟烃（CFCs）吗？他们在这里已经连续多年对氯氟烃进行现场检测，但发现即便是替代品也同样存在问题。
After the CFCs were the interim replacements, HCFCs, and then the replacements for those, HFCs.
继氯氟烃（CFCs）之后，出现了一种临时替代产品——氢氯氟烃（HCFCs），随后又有了进一步的替代品，即氢氟烃（HFCs）。
It's only recently we've had the technology to be able to measure those, to build up a history back in time to 1978.
我们直到最近才发展出了相关技术，能够对这些物质进行测量，并追溯其历史记录至1978年。
That would not be possible without the archive.
若无档案存档，这将无法做到。
Some of the measurements we do take just 20 or 30ml of air.
我们进行的某些测量只需要20或30毫升空气。
We can actually take measurements down to parts per trillion.
我们能够精确到万亿分率水平进行测量。
There was one more thing that Paul showed me back at Melbourne.
在墨尔本，保罗还向我展示了另外一样东西。
The first tank taken here in 1978. It's not the oldest one in the archive.
这里的第一辆坦克是在1978年带来的。它并非馆藏中年代最久远的。
Several years ago, we did a media story, and we started to get inquiries from the public saying, "we've got older air than you."
几年前我们进行了一次媒体报道之后，就陆续接到了公众的反馈，他们说：“我们这儿有的空气比你们展示的还要悠久。”
And it turns out there was a lot of people out there with old scuba tanks sitting in their garages.
结果是，许多人的车库里都存放着一些古旧的潜水气瓶。
And most scuba divers kept a diary of when they dived, when and where the tank was filled.
而且，多数潜水爱好者都会详细记录自己潜水的日期以及气瓶的充气时间和地点。
So people started to donate their scuba tanks.
因此，人们便开始捐出他们闲置的潜水气瓶。
So we now have air back to 1956.
因此，我们现在手上有的空气可以追溯到1956年。
For some trace gases that we're interested in, are perfectly fine to take the measurements.
对于那些我们所关注的痕量气体，使用这些气瓶进行测量是完全没问题的。
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