加载中…农民获得来自外层空间的帮助
(2015-07-27 11:31:32)
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股票 |
分类： 科学与技术 |
NASA的这个卫星观测站利用天线大面积扫描，以测量土壤湿度，并根据综合数据每两到三天制作一份全球土壤湿度图。（图片由NASA提供）
如果你想了解土壤中水分的分布情况，你会怎么办？挖一个洞吗？
不用。你可以从高空获得更好的观测图像。这就是美国航空航天局（NASA）提供的解决办法。
携带土壤湿度观测卫星的德尔塔II(Delta II)运载火箭在1月31日发射之前 (© AP Images)
今年一月，美国航空航天局发射了“土壤湿度主动-被动探测”卫星(Soil Moisture Active Passive satellite)，目的是收集世界各地的土壤水分数据。这个绕地球轨道运行的观测卫星利用微波雷达和辐射仪能够“看透”云层和植被，并可以观测到土壤表层五厘米的深度范围，来测量其含水量，无论是液态水还是结冰的水。观测的目的是为了更好地了解地球的三大基本系统：水、能量和碳循环。
专家预期该卫星将制作出最高分辨率的、有史以来最准确的土壤湿度图。麻省理工学院（Massachusetts Institute of Technology）的该项目科学小组负责人达拉·恩特卡比(Dara Entekhabi)说，结合从其他太空项目得出的数据，土壤湿度图将对于地球上水的循环——环境中的水存储和水流动——如何随着气候的变化在全球和区域范围内不断变化，进行“更深入的分析”。这些信息将有助于改进对全球气候变化的预测。
卫星土壤湿度数据可用于帮助非洲农民了解什么样的作物最能适应缺水和土壤侵蚀条件(© AP Images)
世界各地的农民都可以从此次为期三年的卫星观测任务中受益，因为卫星数据将会帮助他们更好地管理农作物。各国政府和国际组织可以利用这些数据来更准确地预测洪水和干旱，并改进饥荒早期预警系统。
四月份制作的第一份土壤湿度地图显示出美国西南部和澳大利亚内陆的干旱状况，以及在美国中西部地区，还有美国、欧洲和亚洲东部地区的湿度条件。[请参见NASA制作的土壤湿度图]
Help for farmers…from outer space
If you wanted to find out how water is distributed in soil, what
would you do?
No, you would go up in the sky to get a better view. At least that was NASA’s answer.
A Delta II rocket carrying the soil moisture satellite before the January 31 launch (© AP Images)
In January, the U.S. space agency launched the Soil Moisture Active Passive satellite, designed to collect data on soil moisture around the globe. The orbital observatory uses microwave radar and radiometer instruments to “see” through clouds and vegetation and peer into the top five centimeters of soil to measure its water content, both liquid and frozen. The goal is to better understand Earth’s three fundamental systems: its water, energy and carbon cycles.
Experts expect the satellite to produce the highest-resolution, most accurate soil moisture maps ever obtained. Combined with data from other space missions, they will reveal “deeper insights” into how Earth’s water cycle — the storage and flow of water in the environment — is evolving globally and regionally in response to climate change, said Dara Entekhabi, who heads the project’s science team at the Massachusetts Institute of Technology. This information will help improve global climate change projections.
Satellite soil-moisture data can be used to help African farmers learn what kind of crops adapt best to water shortages and soil erosion. (© AP Images)
Farmers worldwide can benefit from the three-year mission because the satellite data will allow them to better manage crops. Governments and international organizations can use the data to forecast floods and droughts more accurately and to improve famine early-warning systems.
The first soil moisture map produced in April showed dry conditions in the southwestern United States and in Australia’s interior, as well as moist conditions in the U.S. Midwest and in eastern regions of the United States, Europe and Asia.
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