第七期杂志选文——《亚洲空气污染致使太平洋风暴加强》 - 树屋经典影视论坛

Buildings in Lianyungang, China, are shrouded in smog on December 8, 2013. Aerosol pollution from Asia is likely leading to stronger cyclones in the Pacific, more precipitation, and warming temperatures at the North Pole.

2013年11月8日，中国连云港笼罩在一片雾霾中。亚洲的气溶胶污染很可能会招致更强的太平洋飓风，更大的降雨量，并且使得北极的气温升高。

What happens in Asia doesn't stay in Asia, a new study warns. Pollution from booming economies in the Far East is causing stronger storms and changing weather patterns over the Pacific Ocean, which in turn is changing weather in North America, scientists report.

最新的一项研究警告称：此次污染将不仅仅局限于亚洲。科学报告表明，这些源于远东经济发展而产生的污染将会带来更为严重的风暴，并且会改变太平洋地区的天气模式，继而导致北美地区气候的改变。

"Whether the weather [in North America] will change in a good direction or bad is hard to say at this time," says Renyi Zhang, a professor of atmospheric sciences at Texas A&M University in College Station. Zhang is a co-author, along with several scientists from the U.S. and China, of a study released in the Proceedings of the National Academy of Sciences on Monday.

“[北美的]气候是变好还是变坏目前还很难说，”美国德州农工大学的大气科学教授张仁义说。他和来自美国和中国的几位科学家一同合作完成了一篇学术论文，这篇文章于周一在美国国家科学院院刊上发表。

The scientists say pollution from Asia is likely leading to stronger cyclones in the midlatitudes of the Pacific, more precipitation, and a faster movement of heat from the tropics toward the North Pole. As a result of these changes, "it's almost certain that weather in the U.S. is changing," says Zhang.

科学家们称亚洲的污染很有可能会导致太平洋中纬度地区飓风增强，带来更多的降水量，并且热量将更快地从热带向北极圈蔓延。分析这些变化将带来的后果，张教授表示：“几乎可以肯定的是美国的气候会发生改变。”

Zhang and his colleagues used computer modeling to study the effects on the weather of aerosols, which are fine particles suspended in the air. The main natural aerosols over the Pacific are sea salt tossed up by waves and dust blown off the land.

张教授和他的同事们用计算机模拟技术来研究悬浮在空气中的微小的气溶胶颗粒对天气的影响。太平洋区域自然形成的气溶胶是由被海浪打起的盐粒和从陆地上吹过来的沙尘组成的。

But those natural particles are now increasingly outnumbered by human-made ones. According to Zhang, the most significant aerosols the team considered are sulfates, which are emitted primarily by coal-fired power plants. Other aerosol pollutants are released by vehicle emissions and industrial activities.

不过，人为而至的颗粒物的数量正逐渐超过这些自然形成的颗粒物。据张教授说，他们团队认为主要由化石燃料厂排放的硫酸盐是悬浮颗粒物的最大源头。还有一些悬浮颗粒物是由机动车排放的尾气和工业生产所产生的。

In the atmosphere, such aerosols scatter and absorb sunlight, and thus have both cooling and warming effects on climate. But they also affect the formation of clouds and precipitation—and the magnitude of that indirect effect on clouds is one of the biggest uncertainties hampering scientists' ability to forecast climate change.

大气中的这些颗粒散射并吸收了太阳光，这样一来，在降温的同时又升高了温度。他们还影响了云层和降水的形成----对云层的影响产生了一个巨大的隐患：科学家们不能准确的预报天气了。

Clouds form when water vapor condenses around aerosol particles to form liquid droplets. Because pollution increases the number of particles, it leads to more water droplets—but smaller ones. Those smaller droplets in turn rise to greater heights in the atmosphere—and even form ice—before they precipitate back out.

水蒸气在颗粒物周围冷凝形成了小水珠，小水珠凝聚最终形成了云。因为大气污染导致颗粒物增加，由此形成了更多但是更小的水珠。这些小水珠会进入更高的大气层----在那里可能会结成冰珠----在它们降落之前。

In an earlier paper, Zhang and his colleagues used satellite data to show that the amount of "deep convective clouds," including thunderstorms, had increased over the North Pacific between 1984 and 2005. The most likely reason, they concluded, was an increase in aerosol pollution from Asia. "The intensified Pacific storm track likely has profound implications for climate," they wrote.

在早些的报道中，张教授和他的同事们利用卫星数据，指出了从1984年到2005年，北太平洋上的对流云团（包括暴风雨）数量在不断增加。他们认为，导致这一现象最有可能的原因就是亚洲的颗粒污染的加剧，“太平洋风暴的路径更加密集，这似乎对气候有着更深的影响，”报道中写到。

In the recent study the scientists took a first stab at considering those global implications. Standard global climate models simulate the atmosphere at grid points that are too widely spaced to resolve the fine-scale processes involved in cloud formation—which is one reason clouds remain such a knotty problem for climate scientists. But the researchers found a way to embed a "cloud resolving model" into a conventional climate model.

在最近的研究中，科学家们首次尝试考虑这些全球性的影响。标准全球气候模型用格点来模拟大气，但它们分布太宽，导致不能在精细尺度下解析云层形成的过程——这正是云层对于气候科学家来说依然是一个棘手问题的原因之一。但研究人员发现了一种将“云解析模式”嵌入传统气候模型的方法。

They then used that "multiscale" model to compare the preindustrial atmosphere of 1850, when levels of aerosol pollution over the Pacific were low, with the present atmosphere.

然后，他们使用了“多尺度”模式，将1850年时太平洋上悬浮物污染水平还比较低的工业化之前的大气，同现今的大气进行了比较。

The simulations confirmed that human-made aerosols are now spreading across the Pacific and having large effects on the storms that sweep east during winter. The storms are more vigorous than they would be without pollution, with more ice and a broader "anvil" shape to the cloud tops. And those more vigorous storms are having a significant effect on the global atmosphere: They're increasing the flow of heat from the equatorial region toward the Arctic, says Zhang.

这些模拟证实，人为形成的悬浮颗粒正在逐渐蔓延到太平洋，并对冬季时向东横扫的风暴有很大的影响。风暴比没有污染影响时要猛烈的多，并量更多，并且在云层顶端形成了更宽广的“砧”。而那些更猛烈的风暴对全球大气有着显著的影响：它们增强了从赤道地区到北极的热流，张教授说。

What about North America? The Pacific storm track has a big effect on American weather, and large-scale natural changes like El Niño and La Niña are known to disrupt its usual pattern, leading to floods and droughts.

那北美地区又怎么样呢？太平洋风暴的轨迹对美国的气候有着很大的影响，人们知道像厄尔尼诺和拉尼娜这样的大规模的自然变化会破坏美国气候通常的模式，并导致洪水和干旱。

"What we have shown is that aerosols from Asia can get transported over the Pacific and change weather in North America," Zhang says—but nailing down the nature of the change will require more research.

“我们已经指明的是，来自亚洲的悬浮颗粒可以跨越太平洋，对北美的气候造成影响”，张教授说，但要确定这种改变的本质，还需要进一步研究。

"We've been getting some weird weather, such as a very cold winter [in the eastern U.S.], so the next question is, does that have something to do with Asian pollution?"

“我们最近经常看到怪异的天气，比如一个非常寒冷的冬天[在美国东部]，所以接下来的问题是，这和亚洲地区的污染有没有关系？”