美国航天局2009年8月27日拍摄到的图像就像流动的河水一样,冰川向下流动,支流汇合形成更大的河流。但在水急的地方,冰却在爬行。因此,冰川会聚集灰尘和污垢,并承载着过去运动的长期证据。2009年8月27日,美国国家航空航天局Terra卫星上的先进星载热发射和反射辐射计(ASTER)从头顶飞过,阿拉斯加苏西特纳冰川显露出了它漫长而磨砺的旅程。这幅卫星图像结合了红外线、红色和绿色的波长,形成了一幅假彩色图像。植被是红色的,冰川表面布满了无污垢的蓝色冰和覆盖着污垢的棕色冰。相对清洁的冰从北部的支流注入。在图像中心附近,冰川表面显得特别复杂,一条支流将主冰川中的冰稍微向南推。美国地质调查局(由国家冰雪数据中心存档)的研究人员拍摄的一张照片显示,1970年,苏西特纳冰川同样复杂,无污垢和污垢覆盖的表面形成了条纹、曲线和U形转弯。苏西特纳流过地震活跃区。事实上,2002年11月,该地区发生了7.9级地震,沿着一条先前未知的断层。地质学家推测,地震在冰川表面造成了陡峭的悬崖和斜坡,但事实上,大部分混乱是支流冰川涌动的结果。冰川涌动是一种典型的短命事件,冰川的移动速度是其正常速度的许多倍,当融水在底部聚集并润滑流动时就会发生。这些水可能是由冰川顶部积聚的融水湖提供的;在这张图片的左下角可以看到一些。下伏基岩也会导致冰川涌浪,软质、易变形的岩石会导致更频繁的涌浪。美国国家航空航天局地球天文台图片由杰西艾伦和罗伯特西蒙创建,使用由美国国家航空航天局/GSFC/METI/ERSDAC/JAROS和美国/日本ASTER科学团队提供的数据。标题由Michon Scott提供。仪器:Terra-ASTER Credit:nasa地球观测台,太阳系探索和天体物理学。戈达德通过贡献令人信服的科学知识来推进宇航局的任务,在美国航天局的成就中发挥了领导作用。关注我们的twitter加入我们的twitter?ref=tsd“rel=”nofollow“>脸谱网
Susitna Glacier, Alaska
NASA image acquired August 27, 2009 Like rivers of liquid water, glaciers flow downhill, with tributaries joining to form larger rivers. But where water rushes, ice crawls. As a result, glaciers gather dust and dirt, and bear long-lasting evidence of past movements. Alaska鈥檚 Susitna Glacier revealed some of its long, grinding journey when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA鈥檚 Terra satellite passed overhead on August 27, 2009. This satellite image combines infrared, red, and green wavelengths to form a false-color image. Vegetation is red and the glacier鈥檚 surface is marbled with dirt-free blue ice and dirt-coated brown ice. Infusions of relatively clean ice push in from tributaries in the north. The glacier surface appears especially complex near the center of the image, where a tributary has pushed the ice in the main glacier slightly southward. A photograph taken by researchers from the U.S. Geological Survey (archived by the National Snow and Ice Data Center) shows an equally complicated Susitna Glacier in 1970, with dirt-free and dirt-encrusted surfaces forming stripes, curves, and U-turns. Susitna flows over a seismically active area. In fact, a 7.9-magnitude quake struck the region in November 2002, along a previously unknown fault. Geologists surmised that earthquakes had created the steep cliffs and slopes in the glacier surface, but in fact most of the jumble is the result of surges in tributary glaciers. Glacier surges鈥攖ypically short-lived events where a glacier moves many times its normal rate鈥攃an occur when melt water accumulates at the base and lubricates the flow. This water may be supplied by meltwater lakes that accumulate on top of the glacier; some are visible in the lower left corner of this image. The underlying bedrock can also contribute to glacier surges, with soft, easily deformed rock leading to more frequent surges. NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Michon Scott. Instrument: Terra - ASTER Credit: NASA Earth Observatory NASA Goddard Space Flight Center enables NASA鈥檚 mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA鈥檚 accomplishments by contributing compelling scientific knowledge to advance the Agency鈥檚 mission. Follow us on Twitter Join us on Facebook

标签: 太空探索, 卫星, 冰川, 阿拉斯加, 戈达德太空飞行中心, 阿拉斯加苏西特纳冰川, 苏斯蒂纳冰川

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