飞机尾气可以使云朵更白
文章来源:未知 文章作者:enread 发布时间:2016-06-23 08:26 字体: [ ]  进入论坛
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Clouds may have a net warming or cooling effect on climate, depending on their thickness and altitude. Artificially formed clouds called contrails form due to aircraft effluent. In a cloudless sky, contrails are thought to have minimal1 effect on climate. But what happens when the sky is already cloudy? In a new study published in the journal Nature Communications, scientists at ACES2 and colleagues from the UK show that contrails that are formed within existing high clouds increase the reflectivity of these clouds, i.e. their ability to reflect light. The researchers hope that their discovery offers important insights into the influence of aviation on climate. "Normal contrails are the stripes you sometimes see behind high-flying aircraft. Lots of times these contrails disappear fairly quickly. Other times they stick around for a while, and even spread out, sometimes considerably3. There has been a lot of work done to find out how these form, and what kind of climatic effect they have - which is estimated to be rather small. Figuring out what kind of effects airplanes have while flying through clouds that are already present in the atmosphere has been much more difficult," says Kevin Noone, Professor at ACES.
 
The researchers used a combination of flight tracking data and satellites equipped with sensitive lasers for detecting small changes in cloud optical thickness, i.e. the degree to which a cloud prevents light passing through it. When they looked at flight tracks from Honolulu to LA and Seattle to San Francisco, they found a significant increase in the optical thickness of the clouds close to the flight tracks compared to those further away. In other words, the clouds close to flight tracks were more reflective or "brighter."
 
" Such effects only occur in certain latitude4 bands, so aircraft flying on polar routes in the Northern Hemisphere and close to the Equator are unlikely to produce these sorts of clouds. The most important areas are in the Northern and Southern mid-latitudes. Work is in progress to calculate the climatic effects of the changes we've observed," says Kevin Noone.


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1 minimal ODjx6     
adj.尽可能少的,最小的
参考例句:
  • They referred to this kind of art as minimal art.他们把这种艺术叫微型艺术。
  • I stayed with friends, so my expenses were minimal.我住在朋友家,所以我的花费很小。
2 aces ee59dee272122eff0b67efcc2809f178     
abbr.adjustable convertible-rate equity security (units) 可调节的股本证券兑换率;aircraft ejection seat 飞机弹射座椅;automatic control evaluation simulator 自动控制评估模拟器n.擅长…的人( ace的名词复数 );精于…的人;( 网球 )(对手接不到发球的)发球得分;爱司球
参考例句:
  • The local representative of ACES will define the local area. ACES的当地代表将划定当地的范围。 来自互联网
  • Any medical expenses not covered by ACES insurance are the sole responsibility of the parents. 任何ACES保险未包括的医疗费用一律是父母的责任。 来自互联网
3 considerably 0YWyQ     
adv.极大地;相当大地;在很大程度上
参考例句:
  • The economic situation has changed considerably.经济形势已发生了相当大的变化。
  • The gap has narrowed considerably.分歧大大缩小了。
4 latitude i23xV     
n.纬度,行动或言论的自由(范围),(pl.)地区
参考例句:
  • The latitude of the island is 20 degrees south.该岛的纬度是南纬20度。
  • The two cities are at approximately the same latitude.这两个城市差不多位于同一纬度上。
TAG标签: climate clouds contrails
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