成吉思汗陵墓追踪大法，北极熊表示好用极了

Genghis Khan got his dying wish: despite attempts by archaeologists and scientists to find the Mongolian ruler’s final resting place, the location remains a secret 800 years after his death. The search for his tomb, though, has inspired an innovative project that could help protect polar bears.

成吉思汗实现了他的遗愿：尽管在他死后800年间，考古学家和科学家多次试图寻找这位蒙古帝王的安息之地，但墓葬的位置仍是一个未解之谜。不过寻找成吉思汗墓的过程却为保护北极熊行动提供了灵感。

“I randomly tuned into the radio one night and heard an expert talking about the use of synthetic aperture radar [SAR] to look for Genghis Khan’s tomb,” says Tom Smith, associate professor in plant and wildlife sciences at Brigham Young University (BYU) in Utah. “They were using SAR to penetrate layers of forest canopy in upper Mongolia, looking for the ruins of a burial structure.”

犹他州杨百翰大学(BYU)植物与野生动物科学副教授Tom Smith说:“一天晚上，我无意间打开收音机，听到一位专家在谈论如何使用合成孔径雷达(SAR)寻找成吉思汗的陵墓。他们在蒙古北部使用SAR穿透森林树冠层，寻找墓葬结构的废墟。”

Talking to engineers, including BYU’s Dr David Long, Smith learned that SAR is used by the military to detect enemy camps, tanks and vehicles hidden beneath camouflage and is being studied as a potential tool for finding avalanche survivors. He and the team at Polar Bears International (PBI) had been looking for a technology to detect polar bear dens. “It was very serendipitous that I heard that broadcast,” says Smith.

在与杨百翰大学的David Long博士等工程师的交谈中，Smith了解到SAR是一种广泛应用于军方的技术，用于探测敌军伪装下的军营、坦克和车辆。并且研究人员还试图将它用于探测救援雪崩幸存者。David Long博士以及北极熊国际组织（PBI）一直在寻找一种探寻北极熊巢穴的技术。他说：“我听到这条广播纯属偶然。”

Successful pilot tests using SAR to find simulated polar bear dens took place in Alaska’s Prudhoe Bay in 2014 and 2015. The project was resurrected with trials in March 2021 on a snowy mountain plateau in Utah’s Manti-La Sal national forest. SAR detects objects by sending pulses of radio waves; sensors pick up the echo or “bounce” to map an area. The aim is to find the right frequency, a sweet spot, that can penetrate snow but still detect a bear.

在2014年和2015年，实验人员在阿拉斯加的普拉德霍湾成功尝试使用SAR技术探测人工模拟的北极熊巢穴。此项目在2021年3月份再次启动，在犹他州曼蒂-拉萨尔国家森林的雪山高原上开展实验。SAR技术通过发送无线电波脉冲来探测目标，传感器接受反弹的电波，从而绘制一个地区的地图。研究人员需要找到一个合适的频率，让无线电波能穿透雪层的同时还能检测到北极熊。

With fewer than 26,000 polar bears thought to be left globally and an estimated decline of 40% in some populations, such as the southern Beaufort Sea, every den and bear counts.Getting reliable data on denning sites is vital. “The Arctic national wildlife refuge is the perfect example,” says BJ Kirschhoffer, PBI’s director of field operations, who led the latest tests in Utah.

据统计，全球北极熊已不到26,000只，南波弗特海等地区的北极熊数量锐减了40%。因此，每一个熊窝和每一只北极熊都很重要。获取北极熊穴居位置的可靠数据至关重要。“北极国家野生动物保护区是一个完美的例子，”PBI野外行动的主管BJ Kirschhoffer说，他在犹他州领导了最新的试验。

“Industry wants to go in and pump oil. If we have a tool that definitively says exactly where polar bear dens are, that means keeping people away from those places. If we want bears, we need baby bears, so we’ve got to protect those dens.”

“工业界想要进入北极熊栖息地开采石油，如果有技术能确定洞穴的位置，人们就能避开这些地方，要想让北极熊正常繁衍生息，就必须保护洞穴的安全。”

The current technology for detecting dens, forward-looking infrared (FLIR), which detects heat, is less than 50% effective. Smith likens it to a “divining rod”. SAR gives a wider sweep and radar data provides specific locations, rather than just an image. It works in adverse conditions, whereas wind, snow, ice and fog can render FLIR useless. “We’d spend days out on the tundra at 40 degrees below zero, looking where FLIR said there was a den and there was nothing,” Smith says.

目前通过热量探测来寻找洞穴的前视红外线(FLIR)有效性不足50%，Smith把它比作“探测棒”。相比之下，SAR的扫描范围更广，雷达数据也可以提供具体位置而不仅是图像；它能在恶劣环境下工作，而风、雪、冰和雾却会让FLIR失效。“我们曾按照FLIR的指示，在零下40度的苔原上蹲守了好几天，但那里并没有所谓的洞穴，”Smith说。

There are also hopes it could soon be possible to do polar bear surveys from satellites in space. “A satellite going over the Arctic, giving an idea of polar bear numbers and movements, would be transformative,” says Geoff York, PBI’s senior director of conservation. “Radar engineers we work with at BYU say the technology exists. In the next decade, we could see that shift. It would be a massive gamechanger.”

人们还希望不久后便能通过太空卫星勘测北极熊的情况。PBI高级保护主任Geoff York说：“卫星若能飞掠北极圈监测北极熊的数量与活动，那将会是一场技术变革。和我们一起在杨百翰大学工作的雷达工程师们认为这项技术是存在的，未来十年若能应用在北极熊的保护上，将具有革命性的意义。”