雷雨时划破长空的闪电有一个你不知道的功能，那就是净化空气，而且还有助于抗击全球气候变暖。新研究发现，闪电会释放大量的“化学清洗剂”，帮助大气自我净化。[Photo/Pexels]闪电的功能是什么？听上去可能像是一个深刻的哲学问题，但是科学家最近发布的一项研究结果也许能对这一问题的答案带来一些启示。What is the purpose of lightning? That might sound like a deeply philosophical question, but scientists may have shed some more light on the answer with the results of a recently released study.这项四月末发表在《科学》杂志上的新研究发现，闪电对全球气候变化的影响力可能比科学界先前所了解的更大。研究人员在报告中写道：“闪电会提高大气自我净化的能力。”The new study published at the end of April in Science found that lightning may play a bigger role in global climate change than was previously known by the scientific community. "Lightning increases the atmosphere's ability to cleanse itself," the researchers wrote in the study.许多人对闪电潜在的致命危害很熟悉，基于1989年到2018年的数据，美国每年平均有43人因闪电而丧生。尽管被闪电击中的概率相当低，一年被闪电击中的概率只有122.2万分之一，一辈子的概率只有15300分之一，但是长久以来气象界一直敦促人们在暴雨来临时采取适当的防范措施以保证安全，暴雨经常会引发闪电，即使不是强暴雨也可能出现闪电。Many are familiar with the potentially deadly hazards posed by lightning, which is blamed for an average of 43 fatalities in the United States each year, based on data from 1989 to 2018. Although the odds of being struck are quite low -- 1 in 1,222,000 in a given year and 1 in 15,300 in a lifetime -- many in the weather community have long urged people to take proper precautions to stay safe amid storms, which can frequently trigger lightning, even without turning severe.然而，研究人员最近发现了闪电的一个惊人的有益影响。However, the researchers recently uncovered a surprising and beneficial impact of lightning.根据美国国家气象局的数据，地球上每年发生的闪电次数可达近2000万次，雷雨过程中闪电可行进10到12英里（16到19公里），瞬间让空气升温华氏5万度。The Earth is struck by lightning nearly 20 million times each year, and bolts of lightning can travel as much as 10 to 12 miles from a thunderstorm, instantly heating the air to 50,000 degrees Fahrenheit, according to the National Weather Service.这项研究综合了12所大学和气象机构的9位气象研究员的成果。研究基于2012年美国宇航局DC-8风暴追逐机开展的一项空中飞行实验，实验中的飞机用于查看雷暴云顶层的砧状云。The study, which included contributions from nine atmospheric researchers across a dozen universities and meteorological agencies, was based on an airborne research flight conducted by a NASA DC-8 storm-chasing plane in 2012. The plane was used to examine the top portion of thunderstorm clouds, which are known as anvils.据ABC新闻网报道，该研究的合著者、宾夕法尼亚州立大学的气象学和大气学教授威廉·布龙博士称，研究人员一开始认为飞机上用来测量大气中的羟基自由基的设备有问题，直到他们观察到羟基自由基水平的飙升和闪电有关。According to Dr. William Brune, a professor of meteorology and atmospheric sciences at Pennsylvania State University and co-author of the study, researchers initially thought there was a problem with the equipment on the plane, which was being used to measure the hydroxyl radicals (OH) in the atmosphere until they realized spikes they observed corresponded with lightning flashes, ABC News reported.[Photo/Pexels]被Science Direct数据库描述为“化学清洗剂”的羟基自由基是大气中发现的重要化合物，可以和其他有机分子发生反应。Hydroxyl radicals, described as a "chemical scavenger" by Science Direct, are important chemical compounds found in the atmosphere due to the reactive nature with other organic molecules.研究人员先前了解到，闪电可以有助于清洁大气，但是没有证据表明闪电可以产生羟基自由基这样的化合物。Researchers previously understood that lightning could help to clean the atmosphere, but there was no evidence that it could generate compounds like these radicals.布龙表示：“从来没有人见过大气自然产生这么多羟基自由基。”"No one has seen that much in the atmosphere from natural processes, ever," Brune said.因此，研究估计，地球大气中自然发生的氧化或清洁有2%到16%是由闪电完成的。As a result, the study estimates that somewhere between 2% and 16% of the oxidizing, or cleaning that happens naturally in the Earth's atmosphere, is done by lightning.为什么大气中的氧化很重要？因为氧化过程有助于降低大气中一氧化碳和甲烷等化学物质含量。经证实，这些被称为温室气体的化学物质导致气温升高，而气温升高和气候变化有关。Why is this significant? The oxidation process helps to reduce chemicals like carbon monoxide and methane in the atmosphere. These chemicals, known for being greenhouse gases, have been proven to contribute to rising temperatures associated with climate change.研究人员表示，还需要开展更多研究，才能确定闪电对于抗击全球气候变化的贡献程度。Researchers say that more studies will need to be conducted to verify the degree to which lightning contributes to the fight against global climate change.