地下光缆具有监测恶劣天气的潜力

地下光缆具有监测恶劣天气的潜力

Take a moment to think about the surface ground beneath your feet. Plunge deeper still and think about the world unseen. There are networks of tree roots in the soil, but also networks of another sort: fiber-optic cables that connect us to each other via phone and Internet service.

花点时间想想你脚下的地面。再深一些，想想看不见的世界。土壤中有树根构成的网络，但也有另一种网络:通过电话和互联网服务将我们彼此连接起来的光纤电缆。

Researchers from Penn State University have developed an innovative idea for piggy-backing on these existing cables: severe weather monitoring. The team turned to their own campus as a testing ground during a thunderstorm on April 15 of this year. Using distributed acoustic sensing (DAS) array technology, they sent a laser down a hair-thin fiber inside miles of cables 1 meter (3.3 feet) deep under the campus and took measurements every 2 meters (6.5 feet), making for a total of 2,000 sensors.

宾夕法尼亚州立大学的研究人员开发了一种利用现有电缆的创新想法:恶劣天气监测。在今年4月15日的一场雷雨中，该团队将自己的校园作为试验场。利用分布式声波传感(DAS)阵列技术，他们将一束激光发射到校园地下1米(3.3英尺)深处的一根细如发丝的光纤中，每隔2米(6.5英尺)测量一次，总共有2000个传感器。

If there is any change in the external energy on the ground above, even walking steps, you will have a very small change that's going to stretch or compress the fiber, said Tieyuan Zhu, assistant professor of geophysics at Penn State. "The laser is very sensitive and can detect these small changes."

宾夕法尼亚州立大学地球物理学助理教授Tieyuan Zhu说:“如果地面上的外部能量有任何变化，即使是步行，你也会有一个非常小的变化，它会拉伸或压缩纤维。”“激光非常敏感，可以探测到这些微小的变化。”

During a storm such as the one in April, thunder from above smashes the ground and acoustic pressure spreads like a wave in a pond. These thunderquakes are registered and recorded, providing “yet another way to track thunderstorms and help with public safety and emergency response, especially in urban areas," said David Stensrud, co-author of the study published in the Journal of Geophysical Research: Atmospheres.

在四月的暴风雨中，从上空传来的雷声击碎了地面，声压像池塘里的波浪一样扩散开来。《地球物理研究杂志:大气》(Journal of Geophysical Research:)上发表的这篇论文的作者之一戴维·斯坦斯鲁德(David Stensrud)说，这些雷震被记录下来，提供了“另一种追踪雷暴的方式，有助于公共安全和应急响应，尤其是在城市地区。”

The team identified 18 thunder-induced seismic events with peak frequencies ranging from 20 Hertz to 130 Hertz. The arrival time of the thunderquakes allowed the scientists to estimate the phase velocity of the near-surface, the back azimuth, and the path of the source as it moved from northwest to south to northeast. The location data was verified with the National Lightning Detection Network (NLDN).

研究小组确定了18个雷击诱发的地震事件，峰值频率从20赫兹到130赫兹不等。雷震的到达时间允许科学家们估计近地面的相位速度、反方位角和震源从西北到南到东北移动的路径。位置数据通过国家闪电探测网络(NLDN)验证。