科学美国人60秒:Air Pollution Gives Storm Clouds a Stronger, Longer Life

Summertime in India can be unbearably hot. "And the first thing you want, is, get me some clouds, to cool down." Sudip Chakraborty grew up there, in Kolkata. Where he developed a childhood fascination with clouds. "And in like three or four months during monsoon time, it was like, rain, rain, all rain. I like the clouds, the rain, the strength they have. Their importance. It's something like I love them, you know?"
在印度，夏季闷热难耐。你的第一反应是想要得到几朵乌云降温。Sudip Chakraborty在（印度）加尔各答长大。在这里，他的童年时代对乌云十分着迷。而像在季风期间的三或四个月中，雨水终日不息。我喜欢乌云，喜欢雨以及它们所拥有的力量。它们至关重要。就像我爱它们一样，你了解吧?

His love of water vapor led him to study clouds, as a climate scientist at UC Davis. Clouds, he says, are built of tiny aerosol particles of dust or pollution from fossil fuel burning that suck up water vapor. "Now these cloud particles with time they combine with each other, and become big. And when they become big, due to gravity, they fall out, and we call it rain."
作为加州大学戴维斯分校的气候科学家，他对水蒸气的热爱促使他研究乌云。他表示云是由尘埃中微小的悬浮颗粒或由化石燃料燃烧的污染物吸收水蒸气构成。现在，随着时间的推移这些云粒子彼此结合，体积变得越拉越大。当它们体积开始变大，由于重力作用，它们开始降落，我们称之为雨。

Chakraborty studied that process in large thunderstorm systems over the tropics, using data from geostationary and circumpolar satellites. And he found that when more aerosols seed the air, like in places with lots of industrial or agricultural pollution, the same amount of water vapor gets absorbed by a larger number of aerosols… meaning tinier-than-usual cloud particle size.
Chakraborty通过利用同步和极地卫星数据，在热带地区大范围雷暴系统中研究这一过程。他发现当更多的浮质漂浮在空气中，如在有工业或农业污染的地方，相同重量的水蒸气会被大量的悬浮颗粒所吸收，指的是比平常更细小的云粒径。

That's important, because "it makes the cloud bigger and larger and stronger and live longer." Three to 24 hours longer. And "it can produce more extreme storms when the rain finally comes." The study is in the Proceedings of the National Academy of Sciences. [Sudip Chakraborty et al., Relative influence of meteorological conditions and aerosols on the lifetime of mesoscale convective systems]
这一点至关重要，因为它使得乌云的体积变得更大、力量更加强大、持续时间更长。三至24小时。当降雨最终来临时，它可以带来更强烈的风暴。该项研究发表在《美国国家科学院院刊》上。

A silver lining: he says longer-lasting clouds also reflect more light back into space, which could end up cooling the planet—and at least tap the brakes on climate change.
一线希望：他表示，持续时间更长的云朵也将更多的光反射回太空，这可能最终使地球冷却。至少可以为气候变化问题踩下刹车。

—Christopher Intagliata
克里斯托弗·因塔格里塔报道。