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Snow blankets cold regions of the earth, and these time-lapse images from NASA weather satellites. But while satellites can detect the surface of snow, snow's reflective nature makes it hard to tell whether it's thin or deep.
地球寒冷地区冰雪覆盖，美国航空航天局的气象卫星将这些延时图像传回地球。虽然卫星可以探测到雪的表面，但由于反射原理，卫星很难分辨积雪厚度。
For that, Forest Service scientist Frank McCormick says experts (need) to do some digging. "They'll dig a snow pit down to bare ground so that they can take very detailed measurements —everything from temperature to water that's in the snow. "This accurately reviews snowpack's water content. But on a global scale, digging snow pits isn't practical. "We would need thousands upon thousands upon thousands of sites throughout the world."
为此，美国林务局的科学家弗兰克·麦考密克说道，专家们需要做一些挖掘工作。"他们需要在裸露的地表下挖一个积雪坑，这样才能非常详细地测量一切数据，包括温度、积雪含水量。"这能准确反映积雪含水量。但在全球范围内，挖积雪坑的做法不切实际。"我们将需要在全世界成千上万的、许许多多的地方用这种方法测量。"
That's why NASA has launched "SnowEx". It's a five-year project to design a snow satellite that will accurately measure snowpack everywhere.
因此，美国航空航天局开展了一项名为SnowEx的研究项目。该项目为期五年，其目的是研发一颗积雪卫星，用以准确测量任何地方的积雪。
SnowEx Project Leader Edward Kim says knowing snowpack's water content, when it's likely to melt and so on, could help over a billion people. "One out of every six people in the world depends most of their, the majority of their water that they use for drinking and agriculture and industry, comes from snow."
SnowEx项目负责人爱德华·金姆表示，了解积雪含水量、积雪融化时间等，可能会造福10亿多人。"世界上每六个人中就有一个人，他们所需的饮用水、农业用水及工业用水大部分都来自冰雪融水。"
To design the snow satellite, 100 SnowEx scientists are seeking the best ways to remotely measure snowpack's depth, its water content, how surface dust and temperature affect snow, and more. As a first step, they're putting snow sensors on airplanes. "The airplanes carry the sensors of the same type that would eventually be on a satellite."
为研发积雪卫星，参与SnowEx项目的100位科学家正在寻求最佳途径，以便能够远程测量积雪深度、含水量、表层灰尘及温度对积雪的影响等。首先，他们在飞机上放置雪深传感器。"飞机携带的是同类型的传感器，这些传感器最终将应用于同一颗卫星上。"
Snowy Colorado is the first SnowEx testing site. As pilots fly, scientists direct 10 kinds of sensors at the snow, including microwave and laser. They’re seeking accuracy even when terrain is uneven or when trees hide snow.
SnowEx项目首选的测试地点是降雪较多的科罗拉多州。飞机飞行过程中，科学家们不断调校着10种雪深传感器，包括微波传感器和激光传感器。他们想找出那些，即使在地势不平坦或树木将积雪掩盖的情况下，依然测量精准的传感器。
As for which sensors work the best, "Well, that's really hard to say. I mean, if we really knew the answer of that already, we wouldn't need to do this."
至于哪些传感器应用效果最好，"嗯，这真的很难说。我的意思是，如果我们真的已经知道了答案的话，我们就没必要这么做了。"
To fine-tune airborne measurements, the SnowEx team will compare them with snow pit data. SnowEx scientist Charles Gatabe says fitting it all together will require complex calculations, but at its heart, the goal is simple: "Get the data, look at the data, and you know say what the data is telling us.
为了优化机载测量结果，SnowEx项目团队需要将这些数据同积雪坑实地测得的数据进行比对。参与SnowEx项目的科学家查尔斯·盖特贝表示，若想实现数据完全匹配，需要进行大量复杂的运算，但从本质上来说，他们的目标很简单："获取数据、研究数据、向大家说明我们从数据中得到的结果。
There's so many people dependent on snow and given this changing climate, who knows what happens? So if we can get a very good handle how to predict, you know, the changing snow, and the changing climate, I think it's going to benefit a lot of people."
很多人依赖积雪融水解决用水需求，考虑到气候变化，谁知道会发生什么呢？所以如果我们真的能够预测积雪和气候的变化，我认为这将有益于很多人。"
NASA's SnowEx team plans to share their data in open access to help people around the world, wherever there is snow.
美国航空航天局的SnowEx项目团队计划与公众分享其研究数据，以造福世界范围内有降雪的广大地区的人们。
For VOA News, I'm Shelley Schlender, at the Peterson Air Force Base, in Colorado.
VOA新闻，雪莱·施伦德于科罗拉多州彼得森空军基地为您播报。
