喷气式飞机改变飞行高度,减少导致气候变化的航迹云
Jet Altitude Changes Cut Climate-Changing Contrails
487字
2020-03-08 13:05
268阅读
火星译客

理查德·纽斯特德,盖蒂图片社

Increasing or decreasing the altitude of aircraft by a few thousand feet to avoid thin layers of humidity could make a major reduction to contrails' contribution to climate change.

飞行高度增加或降低数千英尺,飞机就能避开较薄的“湿气层”,从而大大减轻航迹云对气候变化的影响。

Airplanes account for about 3 percent of the climate-altering carbon dioxide emissions we add to the atmosphere. But planes are warming the planet in another way. 

我们向大气中排放改变气候的二氧化碳,其中约有3%来自飞机。然而飞机还以另一种方式导致全球变暖。

“So if you look up in the sky, you probably see, at some point, an aircraft. And behind that aircraft are white, fluffy streaks. And that's what we call a contrail.”

“因此你若仰望天空,大概有时会看到一架飞机,后面拖着白色蓬松长尾。我们称之为航迹云。”

Imperial College London engineer Marc Stettler.

——(伦敦大学)帝国理工学院工程师马克·施泰特勒

Contrails are made up of ice crystals that form when aircraft engines emit exhaust that hits the cold air. The ice crystals reflect incoming light from the sun back into space, which has a cooling effect on the atmosphere. But the contrails also stop heat coming up from the ground from escaping into space.

航迹云由冰晶构成:飞机引擎喷出的废气遭遇冷空气,就会生成冰晶。冰晶将射来的太阳光反射回太空,对大气有冷却效应。不过航迹云也拦阻从地表散发的热量向太空逃逸。

“It's reflected back down toward the ground. And so that's a warming effect.”

“这些热量被重新反射回地面,因此航迹云又有加温效应。”

Stettler says, on balance, contrails warm the atmosphere more than they cool it.

施泰特勒说道:总的来说,航迹云对大气的加温效应大过冷却效应。

“And that's primarily because the cooling effect due to reflecting of sunlight can only happen during the day, when the sun's shining, whereas the warming effect due to trapping of outgoing heat happens all of the time.”

“这主要是因为:白天阳光灿烂之时,才会有反射阳光造成的冷却效应;然而拦阻热量向外逃逸导致的加温效应却无时无刻不在发生。”

Some contrails can form clouds that last for up to 18 hours. During that time, they spread out, trapping even more heat. This process allows contrails to warm the planet about as much as the carbon dioxide emissions from aircraft.

有些航迹形成的云状物存在时间多达18小时。在此期间,这些云状物不断扩散,甚至更能拦阻热量逃逸。这一过程导致了以下结果:就对地球的加温效应而言,航迹云几乎等同于飞机所排放的二氧化碳。

But when Stettler and his team analyzed flight data they obtained of Japan airspace, they found that most contrail warming was caused by just 2 percent of flights. And most of those flights originated in the late afternoon—because as the sun goes down, cooling can no longer offset the warming.

然而施泰特勒及其团队分析取自日本空域的飞行数据之时发现:产生大部分航迹云加温效应的航班,仅占航班总数的2%。这些航班大多在傍晚起飞:因为随着日落西山,冷却效应再也无法抵消加温效应。

“And the warming effect persists throughout the evening, into the night.”

“而且加温效应会从傍晚持续到深夜。”

But what if the contrails that contribute the most to warming could be eliminated? Such a change could be achieved if aircraft avoided flying in the thin layers of humidity where contrails form.

然而若能消除最能产生加温效应的航迹云,将会如何呢?如果飞机避开能形成航迹云的较薄“湿气层”,如此改变就可达成。

“By changing the altitude only by a couple of thousand feet, either up or down, it would no longer form a contrail. And so what we found in this study was that by changing the altitude of less than 2 percent of flights, we could actually get rid of just under 60 percent of the warming effect due to contrails.”

“将飞行高度增加或降低仅仅几千英尺,就不会再形成航迹云了。因此,我们在这项研究中发现:少于2%的航班改变飞行高度,实际上就能消除航迹云所产生加温效应的近60%。”

The study is in the journal Environmental Science & Technology. [Roger Teoh et al., Mitigating the climate forcing of aircraft contrails by small-scale diversions and technology adoption]

此项研究成果已发表在《环境科学与技术》期刊上。[罗杰·张(或赵)等人合著的《以小范围空域调整和技术应用减轻航迹云对环境的影响》]

This improved understanding of how to manage contrails presents an opportunity for the aviation industry to reduce its global environmental impact. Think of it as a silver lining in those contrail clouds.

这一论及治理航迹云举措的更深刻见解,为航空工业减轻自身对全球环境的影响提供了机会。请将这一发现看作航迹云层中的一线光明。

—Susanne Bard

——苏珊·巴德

[The above text is a transcript of this podcast.]

[以上内容是本播客的文字实录。]

ABOUT THE AUTHOR(S)

作者简介

0 条评论
评论不能为空