好英语网追逐“巨型冰雹”
In August, a couple of days before his 68th birthday, Leslie Scott, a cattle rancher in Vivian, S.D., went to the post office, where he received some bad news. His world record had been broken, the clerk told him. That is, the hailstone Mr. Scott collected in 2010, which measured eight inches across and weighed nearly two pounds, was no longer the largest ever recorded. Some people in Canada had found a bigger one, the clerk said.
8月，在68岁生日的前几天，南达科他州维维安的牧场主莱斯利·斯科特在邮局得到一些坏消息。办事员告诉他，他保有的世界纪录被打破了。斯科特在2010年捡到的直径约20厘米、重量近900克的冰雹现在这已经不再是有史以来的最大冰雹了。办事员说，加拿大有人找到了一块更大的。
“I was sad all over the weekend,” Mr. Scott said, a few days after he heard the news. “I’ve been telling everybody that my record was broke.”
“整个周末我都很伤心，”斯科特在得知这一消息数日后表示。“我逢人就说我的纪录被打破了。”
2019年，一场超级单体雷暴即将吞没内布拉斯加州因皮里尔附近的一处谷仓。几乎所有冰雹都是在超级单体风暴中产生的，这种风暴带有缓慢旋转的上升气流。
Fortunately for Mr. Scott, this was not quite right. On Aug. 1, a team of scientists from Western University in London, Ontario, collected a giant hailstone while chasing a storm in Alberta, about 75 miles north of Calgary. The hailstone measured five inches across and weighed a little more than half a pound — half the size and one-quarter the heft of Mr. Scott’s. So it was not a world record, but a Canadian one.
对斯科特来说，幸运的是这一消息并不完全准确。8月1日，安大略省伦敦市西安大略大学的一队科学家在卡尔加里市以北约120公里的艾伯塔省追踪一场风暴时，发现了一块巨型冰雹。这块冰雹直径约13厘米，重约300克，体积只有斯科特找到那块的一半，重量也只有四分之一。因此，那并不是世界最大冰雹纪录，只是加拿大本国的。
The Canadian hailstone added to the list of regional records set in the past couple of years, including Alabama’s in 2018 (5.38 inches long, 0.612 pounds), Colorado’s in 2019 (4.83 inches, 0.53 pounds) and Africa’s in 2020 (around seven inches long, weight unknown). Australia set a national record in 2020, then set it again in 2021. Texas’ record was set in 2021. In 2018, a storm in Argentina produced stones so big that a new class of hail was introduced: gargantuan. Larger than a honeydew melon.
这块于加拿大发现的冰雹让过去几年创下的地方纪录又多了一个，这些纪录包括在2018年的阿拉巴马州（长约13.7厘米、280克）、2019年的科罗拉多州（长约12.2厘米、240克）、以及2020年的非洲（长约17.8厘米，重量未知）。澳大利亚在2020年创下了全国纪录，2021年又刷新了纪录。得州的纪录是在2021年创下的。2018年，阿根廷一场风暴中的冰雹大到创造出“巨型冰雹”这一新类别。这种冰雹的体积比白兰蜜瓜还要大。
“It’s one of the few weather hazards that we don’t necessarily build for,” said Ian Giammanco, a meteorologist at the Insurance Institute for Business & Home Safety. “And it’s getting bigger and worse.”
“人类应该无法在这种罕见的天气灾害中幸存，”商业和家庭安全保险协会的气象学家伊恩·贾曼科说。“而这种灾害范围越来越大，程度也愈发严重。”
Although the changing climate probably plays a role in these trends, weather experts say, a more complete explanation might have something to do with the self-stoking interplay of human behavior and scientific discovery. As neighborhoods sprawl into areas that experience heavy hail and greater hail damage, researchers have sought out large hailstones and documented their dimensions, stirring public interest and inviting further study.
气象专家说，虽然这些趋势部分是由气候变化造成的，但更全面的解释可能与人类行为与科学发现之间的自发相互作用有关。随着人类社区扩展到了会出现强冰雹天气且造成破坏更严重的地区，研究人员开始寻找大型冰雹，记录下它们的尺寸，激起了公众的兴趣，并准备开始进一步的研究。
Julian Brimelow, the director of the Northern Hail Project, a new collaboration among Canadian organizations to study hail, whose team found the record hailstone in August, said, “It’s a pretty exciting time to be doing hail research.”
朱利安·布里姆洛是“北方冰雹项目”的负责人，这是加拿大各个研究冰雹的组织开展的一项新合作，在8月发现创纪录冰雹的就是他的团队。他说，“对冰雹研究来说现在正是个激动人心的时期。”
When Ice From the Sky …
当冰块从天而降……
The fixation with big hail goes back to at least the 1960s, when Soviet scientists claimed that they could significantly reduce the size of a storm’s hailstones by dispersing chemicals into the atmosphere. The method, called cloud seeding, promised to save millions of dollars in crop damage a year.
人类对大型冰雹的关注至少可以追溯到上世纪60年代，当时苏联科学家声称，他们可以通过在大气中释放化学物质来大幅缩小风暴中冰雹的体积。他们承诺，这种被称为播云的方法每年能减少价值数百万美元的农作物损失。
In the 1970s, the United States funded the National Hail Research Experiment to replicate the results of the Soviet experiments, this time by cloud seeding in hailstorms above Northern Colorado. Scientists then collected the largest hailstones they could find to see if it worked.
到上世纪70年代，美国资助了国家冰雹研究实验，希望能重复苏联的实验结果，这一次是在科罗拉多州北部的冰雹风暴中进行播云。然后，科学家们再去收集他们所能找到的最大的冰雹，评估此种办法是否有效。
It did not. And a decade of research demonstrated that the Soviet effort probably hadn’t worked either. Both countries eventually gave up on the idea, and hailstone research stalled, although cloud seeding to increase rain and snowfall continued — and continues to this day — around the world.
结果是否定的。十年的研究表明，苏联的努力可能也没有奏效。两国最终都放弃了这个思路，关于冰雹的研究也陷入停滞，尽管在世界各地，通过播云增加降雨和降雪的做法仍在继续，并一直持续到今天。
During that lull, in 1986, a hailstone reportedly weighing 1.02 kilograms — about two and a quarter pounds, the heaviest ever recorded — was collected in Gopalganj, Bangladesh, during a storm that killed 92 people. All record of the hailstone — excepting eyewitness accounts and its purported weight — was lost. The Gopalganj stone became something of a fable among hail researchers, with a moral attached: Big hailstones were out there, but documentation was vital.
在那段停滞期，孟加拉国戈帕尔甘杰1986年的一场风暴造成92人丧生，在风暴中发现的一块冰雹据称重达1020克，是有记载以来的最重纪录。除了目击者的描述和传说中的重量，所有关于这块冰雹的记录都丢失了。戈帕尔甘杰冰雹也成为了冰雹研究者口口相传的故事，并附带了一条准则：大型冰雹是有的，但关键是要进行记录。
This prompted Kiel Ortega, a meteorologist who began doing hail research in 2004, to start cold-calling. Using Google Earth, he found businesses that sat in the paths of storms and rang them for on-the-ground updates. “As much as I like chasing storms,” he said, “at some point, you’re not going to have enough money or people to keep going out.”
这是促使气象学家基尔·奥尔特加开始四处给素不相识的人打电话，他从2004年开始研究冰雹。通过谷歌地球软件，他找到那些位于风暴路径上的店面，并致电请求他们提供地面上的情况更新。“尽管我那么热爱追踪风暴，”他说，“但有时候我不可能有足够的财力或人力每次都赶往现场。”
Weather models indicated where hail might form and what the average size of the hailstones might be, but their predictions were often way off. So Mr. Ortega assembled a team of researchers and undergraduate students to cobble together reports whenever a serious hailstorm formed in the United States. How big was the “hail swath” — the area of the storm that dropped hail? How big was the biggest hailstone?
天气模型会显示冰雹可能在何处形成，其平均体积大概如何，但它们的预测也经常出现很大偏差。因此，每当美国出现强烈冰雹风暴，奥尔特加就会召集一个由研究人员和本科生组成的团队，把各种报告汇总起来。“冰雹带”——也就是下冰雹的地区——有多大？最大的冰雹体积是多少？
Most reports of record hail are made by civilians, but the accuracy is often lacking. The first thing most people do when they find a big hailstone? Take a picture. Second? Show it to their family or friends. Third? Put it in the freezer — where sublimation, the phase change from solid ice to water vapor, can shrink the hailstone over time.
记录冰雹的报告大多来自普通人，准确性往往不足。一般人发现巨大冰雹时的第一反应是什么？拍照。第二件事？给家人或朋友看。第三？放进冰箱，而冰箱里的升华——即从固态冰到水汽的相变——可能会让冰雹随着时间推移而缩小。
… Lands on Your Car
……落到你的车上
Every hailstone has a story cryptically etched in its shape and layers. To decode the story, scientists use mathematical models to predict where hail will fall and what it will look like; they then collect and analyze actual hailstones to refine those models, piecing together a stone’s path from the storm to the ground.
每一块冰雹的形状和分层都有自己的秘密。为了进行解读，科学家们用数学模型来预测冰雹的降落地点及其形状；然后再收集和分析实际的冰雹，以完善模型，拼凑出冰雹从风暴中落到地面的过程。
But some of the most basic features of large hail remain shrouded in mystery; survey procedures are inconsistent, and funding is scarce. How fast do these hailstones fall? What gives a hailstone its shape? How large can a hailstone possibly get?
但因为调查程序不一致且缺乏资金，大型冰雹的一些最基本的特征依然是未知的。这些冰雹的下落速度有多快？是什么决定了冰雹的形状？一颗冰雹可能大到何种程度？
“Hail data are terrible,” Dr. Brimelow said. “It is probably one of the worst data sets on the planet.”
“关于冰雹的数据十分不尽如人意，”布里姆洛说。“有可能是地球上最糟糕的数据集之一。”
Almost all hail is created in supercells, or storms with updrafts of rising air that slowly rotate. Small pieces of ice, called embryos, get swept into those updrafts like “a fountain of particles,” said Matt Kumjian, a meteorologist at Penn State University who studies the internal dynamics of storms. The embryos smash into water droplets, becoming hailstones that continue to grow until they are too heavy to stay suspended and then fall to the ground.
几乎所有冰雹都是在超级单体风暴中形成的，这种风暴带有缓慢旋转的上升气流。宾夕法尼亚州立大学研究风暴内部动力学的气象学家马特·库姆吉安表示，被称为“雹胚”的冰碴像“颗粒喷泉”一样被卷入上升气流。这些雹胚与水滴迅猛融合，变成不断增大的冰雹，直到自身重量无法保持悬浮状态，就会落到地面。
Over the past couple of years, Dr. Giammanco and his colleagues have traveled around North America making 3-D scans of large hailstones. Later in the lab, using “probably the most sophisticated ice machine on the planet,” Dr. Giammanco said, the team recreates the hailstones to calculate their fall speed and the damage they could cause.
过去几年里，贾曼科和同事走遍北美各地，对大型冰雹进行三维扫描。然后，他们会在实验室中利用“或许是地球上最复杂的制冰机”重建这些冰雹，以计算其下落速度和可能造成的损害。
Mr. Ortega and his colleagues have been using high-speed photography to capture large hailstones in motion. This entails sprinting in front of supercells and setting up camera systems to better understand how fast the ice is moving when it hits the ground and what shape it takes just before impact.
奥尔特加和同事一直在使用高速摄影技术来捕捉大型冰雹的动态。这需要冲在超级单体风暴前面装好摄影系统，才能更好地了解冰块落地时的移动速度，以及落地前形成的形状。
Each detail is a clue. A cloudy hailstone layer indicates that the water froze instantly on the embryo, trapping air bubbles inside. Clear ice means the water had time to expand around the embryo before freezing. Spherical hailstones are thought to have tumbled around in the supercell; spiky ones shoot like comets through the storm.
每个细节都是线索。冰雹的层次混浊能大致说明水在雹胚上瞬间冻结，水中气泡都被冻在了里面。冰体清澈意味着水在冻结前还有时间裹着雹胚继续膨胀。球形冰雹被认为是在超级单体风暴中翻滚形成的；尖体冰雹则是像彗星一样穿过了风暴。
The end of a hailstone’s story is often what attracts public attention. If some ice breaks your windshield, do you really care what path it took through a supercell? But, Dr. Kumjian said, retracing the ontogeny of hail can help scientists better predict where and when large hailstones will fall next.
公众的关注点通常在于一块冰雹旅程的终点。如果你的挡风玻璃被冰块砸碎，你真的会在意它如何从一场超级单体风暴穿越而来吗？但库姆吉安说，追溯冰雹的个体发生可以帮助科学家更好地预测未来的大型冰雹将在何时何地落下。