Washington — The heat that seeps out of leaky buildings and the warmth of cars purring in traffic contribute to the mass of heat that pulses into the atmosphere from urban centers. Scientists are now getting a handle on how that heat behaves in the upper atmosphere and influences temperatures elsewhere.
华盛顿 ——从建筑物缝隙泄出的热量和滚滚车流散发的热气导致大量热能从城市中心排入大气。科学家现在正在逐步了解这些热量如何在高层大气中运动并影响其他地方的温度。
Research just published in the journal Nature Climate Change shows that urban heat can change the behavior of major atmospheric systems that sweep across North America and Northern Asia. Produced by a collaboration involving the National Center for Atmospheric Research (NCAR), the work finds that temperatures in places far from the urban heat centers may be pushed up by as much as 1 degree Celsius.
最近刊登在《自然气候变化》（Nature Climate Change）期刊上的研究表明，城市的热效应可以改变覆盖北美（North America）和北亚（North Asia）的主要大气系统的行为。这项美国国家大气研究中心（National Center for Atmospheric Research，NCAR）参与的科研合作成果表明，远离城市热气中心地带的气温可上升高达1摄氏度。
The heat swells can also shift the standard paths for global air currents, the researchers found, such that temperatures in Europe are cooling by as much as 1 degree Celsius with the effects of U.S. urban heat on the North Atlantic jet stream.
研究人员发现热膨胀还可能改变全球大气气流的标准路径，由于受到美国城市的热效应对北大西洋（North Atlantic）高速气流的影响，欧洲的气温正逐步下降，下降幅度最高可达1摄氏度。
"The burning of fossil fuel not only emits greenhouse gases but also directly affects temperatures because of heat that escapes from sources like buildings and cars, " says NCAR scientist Aixue Hu, a co-author of the study. "Although much of this waste heat is concentrated in large cities, it can change atmospheric patterns in a way that raises or lowers temperatures across considerable distances."
美国国家大气研究中心的科学家，研究报告的共同作者胡爱学(Aixue Hu)说，“化石燃料的燃烧不仅排放出温室气体，而且通过从诸如建筑物和汽车等热源释放出的热能直接影响温度。尽管这种废热大部分集中在大城市内，但它能改变大气模式，使距离相当远的地方的温度升高或降低。”
Using a computer model of the atmosphere, the authors found that the influence of this waste heat can widen the jet stream.
研究报告的作者们通过分析大气的电脑模型发现，废热的影响可扩大高速气流的宽度。
"What we found is that energy use from multiple urban areas collectively can warm the atmosphere remotely, thousands of miles away from the energy-consumption regions, " said lead author Guang Zhang of the University of California, San Diego. "This is accomplished through atmospheric circulation change."
研究报告的第一作者，加州大学圣迭戈分校（University of California, San Diego）的张广（Guang Zhang）(音译)说，“我们发现多个城市地区的能源使用合在一起可使距离能源消耗地区数千英里之外的大气变得更加温暖。这是通过大气环流的变化完成的。”
On the global scale, however, urban heat is a tiny fraction — just 0.3 percent — of all the heat that is throbbing off the planet and gliding across higher latitudes by atmospheric circulation. But urban heat in air currents may be having some very localized effects, the study suggests, a theory that explains why some areas are experiencing more winter warming than what has been predicted by computer models.
从全球范围来说，在地球表面散发并通过大气环流逐渐进入高层大气的所有的热量中，城市热能仅占约0.3%的微小比例，但是研究显示，城市热能进入气流可能会产生一些非常局部化的效应，这一原理可以解释为什么某些地区会遭遇比电脑模型预测的更多的暖冬天气。
The urban centers in North America and Asia releasing this concentrated heat also happen to lie directly under major atmospheric activity, said another study co-author, Ming Cai of Florida State University.
研究报告的另一名共同作者，佛罗里达州立大学（Florida State University）的蔡明（Ming Cai）（音译）说，集中释放这种热能的北美和亚洲城市中心正好直接位于主要大气活动带的下方。
"The world's most populated and energy-intensive metropolitan areas are along the east and west coasts of the North American and Eurasian continents, underneath the most prominent atmospheric circulation troughs and ridges, " Cai says. "The release of this concentrated waste energy causes the noticeable interruption to the normal atmospheric circulation systems above, leading to remote surface temperature changes far away from the regions where waste heat is generated."
蔡明说,“世界上人口最密集、能源消耗最多的大都市区位于北美和欧亚大陆的东西海岸，在最显著的大气环流槽脊的下方。这种废能的集中排放对位于上方的正常大气环流系统产生明显的干扰，从而改变远离废热排放地区的地表温度。”
The scientific team behind this work — including NCAR; the Scripps Institution of Oceanography at the University of California, San Diego; and Florida State University — suggests that climate models be tweaked to factor in the influence of urban waste heat.
从事这项研究的科学队伍——包括美国国家大气研究所；加州大学圣迭戈分校斯克里普斯海洋研究所(Scripps Institution of Oceanography)；佛罗里达州立大学——建议对气候模型进行调整以便把城市废热的因素考虑进去。
The largest source of heat on the planet is the sun, the researchers point out. It warms the Earth, and atmospheric circulation redistributes that energy across the globe. The release of urban waste heat is different because it comes from fossil fuel sources, releasing energy that had previously lain dormant in the Earth for millions of years.
研究人员指出，地球上最大的热源是太阳。太阳使地球变得温暖，而大气环流将来自太阳的能量散布到全球各地。城市废热的排放则不同，因这是为它来自化石燃料热源，释放出的是在地球上已沉睡数百万年的能量。
The National Science Foundation sponsors NCAR, which is managed by the University Corporation for Atmospheric Research, a nonprofit consortium of research universities.
美国国家大气研究中心由国家科学基金会(National Science Foundation)资助，由非盈利性的研究性大学联盟大气研究大学联盟（University Corporation for Atmospheric Research）管理。
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