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我今天想和你們談談,關於你在報紙上所看到的頭條新聞背後,科學努力的規模。當與氣候變化有關時,頭條新聞看起來像這樣;當與空氣品質或煙霧有關時,頭條新聞看起來像這樣;它們是相同大氣科學領域的兩個分支。
最近,當聯合國跨政府氣候變遷小組,或說是IPCC,發表其對大氣系統所知情形的報告時,頭條新聞看起來像這樣。該報告是由來自於40個國家,620位科學家所撰寫的。他們針對這個主題,寫了近1000頁的報告。所有報告都進行了審查,是由另外來自於113個國家,400多位科學家和審查者進行的。這是一個大團體,一個相當大的團體。事實上,我們的年度會議,是世界上最大的[自然]科學會議。
每年有超過15000位科學家,為此前往舊金山;每位科學家都隸屬於一個研究團隊,每個研究團隊研究各式各樣廣泛的主題。我們在劍橋的團隊研究的各類主題,包含會影響天氣和氣候的聖嬰振盪現象、衛星數據的同化,以及會產生生物燃料作物的排放物;這也正是我所研究的領域。
在每個研究領域,其中還有更多像我一樣的博士研究生。我們研究的主題極其狹窄,就是如少數進程或分子那樣狹小範圍的東西。我研究的分子之一,叫做異戊二烯,就是這個。這是一個小的有機分子。你可能從未聽說過它。迴紋針的重量約相當於900 × 6 × 10^23-約10的21次方-個異戊二烯分子。
儘管它的重量非常輕,但每年排放到大氣中的重量,卻相當於地球上所有人的重量。這是相當大量的,重量相當於甲烷。因為它的量是如此多,所以對大氣系統確實相當重要。
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以下為系統擷取之英文原文
I'd like to talk to you today about the scale of the scientific effort that goes into making the headlines you see in the paper. Headlines that look like this when they have to do with climate change, and headlines that look like this when they have to do with air quality or smog. They are both two branches of the same field of atmospheric science.
Recently the headlines looked like this when the Intergovernmental Panel on Climate Change, or IPCC, put out their report on the state of understanding of the atmospheric system. That report was written by 620 scientists from 40 countries. They wrote almost a thousand pages on the topic. And all of those pages were reviewed by another 400-plus scientists and reviewers, from 113 countries. It's a big community. It's such a big community, in fact, that our annual gathering is the largest [physical] scientific meeting in the world.
Over 15,000 scientists go to San Francisco every year for that. And every one of those scientists is in a research group, and every research group studies a wide variety of topics. For us at Cambridge, it's as varied as the El Niño oscillation, which affects weather and climate, to the assimilation of satellite data, to emissions from crops that produce biofuels, which is what I happen to study.
And in each one of these research areas, of which there are even more, there are PhD students, like me, and we study incredibly narrow topics, things as narrow as a few processes or a few molecules. And one of the molecules I study is called isoprene, which is here. It's a small organic molecule. You've probably never heard of it. The weight of a paper clip is approximately equal to 900 zeta-illion -- 10 to the 21st -- molecules of isoprene.
But despite its very small weight, enough of it is emitted into the atmosphere every year to equal the weight of all the people on the planet. It's a huge amount of stuff. It's equal to the weight of methane. And because it's so much stuff, it's really important for the atmospheric system.
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因為它對大氣系統很重要,我們長期研究這個分子;我們使它爆炸,並觀察其碎片。這是在西班牙的EUPHORE煙霧室。大氣爆炸或完全燃燒,需時超過你車子反應所需的1.5萬倍。不過,我們依然是觀察其碎片。
我們在超級電腦上運算大量的模型,這正是我所做的研究。我們的模型佔了幾十萬個網格箱,每個都以分鐘為時間標度,計算數百個變量,需要幾個星期來整合它。我們進行了幾十個整合工作,以瞭解所發生的事情。
我們也飛到世界各地尋找這個分子。我最近和其他夥伴參加了在馬來西亞的實地調查;我們在那裡發現了一個位於雨林中央的全球大氣瞭望塔。我們在這個塔上,掛上價值數十萬美元的科學設備,用以尋找異戊二烯。當然,也尋找其他東西。這是位於雨林中央的塔,從上面看的樣子。這是從下面看的樣子。
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Because it's important to the atmospheric system, we go to all lengths to study this thing. We blow it up and look at the pieces. This is the EUPHORE Smog Chamber in Spain. Atmospheric explosions, or full combustion, takes about 15,000 times longer than what happens in your car. But still, we look at the pieces.
We run enormous models on supercomputers; this is what I happen to do. Our models have hundreds of thousands of grid boxes calculating hundreds of variables each, on minute timescales. And it takes weeks to perform our integrations. And we perform dozens of integrations in order to understand what's happening.
We also fly all over the world looking for this thing. I recently joined a field campaign in Malaysia. There are others. We found a global atmospheric watchtower there, in the middle of the rainforest, and hung hundreds of thousands of dollars worth of scientific equipment off this tower, to look for isoprene, and of course, other things while we were there. This is the tower in the middle of the rainforest, from above. And this is the tower from below.
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在實地調查活動一部份,我們甚至還帶了飛機-就是這架飛機,型號是BA146,屬於FAAM(大氣測量飛行設備公司)一般可搭載120至130人。也許你今天就是搭乘類似的飛機到這裡。但我們不只是乘坐它,我們在樹冠頂部上方100米處飛行,以測量這個分子-這是難以想像的危險舉動。
我們必須以一種特別的傾斜度飛行,以進行測量。我們聘請了軍事和測試飛行員來操縱,必須得到特殊飛行許可。當沿著山谷斜坡繞行時,所受到的重力可達至2G,當科學家們在飛機上時,必須全程綁好安全帶以進行測量。所以,你可以想像這架飛機的內部,看起來不像任何你度假時所搭乘的飛機。這是一個飛行實驗室,我們用以測量該地區的這個分子。
我們做了所有這樣的事,以瞭解一個分子的化學性質。當一個像我一樣的學生,對這個分子有某種想法或瞭解時,他們會以這個主題寫一篇科學論文。歷經這趟實地調查後,我們可能會得到幾十個進程或分子的幾十篇論文。
當知識主體建立後,將會有1個副章節,或副章節的子部份,如IPCC的評估,雖然還有其它的。IPCC報告的 11個章節,各有6到10個副章節。所以你可以想像這個努力的規模。在每一個我們所寫的評估中,都會貼上摘要標籤。摘要是寫給非科學領域的讀者看的。我們將這個摘要呈給記者和決策者,以使它成為頭條新聞,就像這樣。非常感謝(掌聲)。
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And on part of that field campaign we even brought an aircraft with us. And this plane, the model, BA146, which was run by FAAM, normally flies 120 to 130 people. So maybe you took a similar aircraft to get here today. But we didn't just fly it. We were flying at 100 meters above the top of the canopy to measure this molecule -- incredibly dangerous stuff.
We had to fly at a special incline in order to make the measurements. We hire military and test pilots to do the maneuvering. We have to get special flight clearance. And as you come around the banks in these valleys, the forces can get up to two Gs. And the scientists have to be completely harnessed in in order to make measurements while they're on board. So, as you can imagine, the inside of this aircraft doesn't look like any plane you would take on vacation. It's a flying laboratory that we took to make measurements in the region of this molecule.
We do all of this to understand the chemistry of one molecule. And when one student like me has some sort of inclination or understanding about that molecule, they write one scientific paper on the subject. And out of that field campaign we'll probably get a few dozen papers on a few dozen processes or molecules.
And as a body of knowledge builds up, it will form one subsection, or sub-subsection of an assessment like the IPCC, although we have others. And each one of the 11 chapters of the IPCC has six to ten subsections. So you can imagine the scale of the effort. In each one of those assessments that we write, we always tag on a summary, and the summary is written for a non-scientific audience. And we hand that summary to journalists and policy makers, in order to make headlines like these. Thank you very much. (Applause)