From: NASA MODIS Web
Posted: Wednesday, November 14, 2012
A large plume of dust blew across southwestern Alaska in early November 2012, shrouding much of the land and Bristol Bay with a light colored veil. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite captured this true-color image on November 6 as it passed over the region. A fine, wide plume passes over the mainland, and then curves with the wind as it crosses the Alaskan Peninsula. In Alaska, dust can arise from glacial flour or from sediments along riverbeds. Glacial flour is created when glaciers slowly grind over rocks, turning them into a fine dust that can be blown aloft by strong winds. There are many glaciers in the region, and dust is common. Also, autumn is the season when river discharge reaches its annual minimum, which means river beds are maximally exposed, and fine river sediment is most likely to rise with the wind. While there are potential sources for this dust close to home, some scientists have suggested a different source of this plume - it may be blowing from far distant China. In early November, severe dust storms struck the Taklimakan Desert of western China, blowing thick layers of dust from that desert eastward. The Ozone Mapping Profiler Suite, (OMPS), an instrument that tracks aerosols worldwide from the Suomi NPP satellite, made observations that indicated dust travelled from the Taklimakan Desert across China, then across the Pacific Ocean to southwestern Alaska from November 2 through November 8, 2012. At this time, and from this Aqua image alone, the source of the massive dust plume cannot be definitively located. However, the massive size and length of the plume created a spectacular event when viewed from space.
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