Landsat-8 Imagery
Landsat-8 imagery — with a spatial resolution of 15 to 30 meters — is available for viewing via the SSEC RealEarth web map server. An example of a swath of false-color Red/Green/Blue (RGB) imagery across the central US between the times of 1630-1640 UTC on 16 January 2016 is shown above. Snow cover and ice (as well as ice crystal clouds) appear as varying shades of cyan in this type of RGB image. Let’s take a closer look at 3 regions along this overpass to examine some interesting features.The northerly flow of arctic air over the still-unfrozen waters of Lake Superior was aiding the development of lake effect snow (LES) bands, some of which were moving inland over the eastern portion of the Upper Peninsula of Michigan. One of the more well-defined LES bands was seen to be moving across the Grand Marais area — a cooperative observer 10 miles south of the city reported 8.5 inches of new snow during the 24-hour period from 12 UTC on 16 January to 12 UTC on 17 January.
Looking farther to the south, an interesting feature was seen in the southern part of ice-covered Green Bay, Wisconsin (below): a channel through the ice (red arrows) had been cut by the US Coast Guard icebreaker Mackinaw during the evening of 14 January, to allow passage for a ship to unload cargo at a dock along the mouth of the Fox River (which empties into the southern end of Green Bay). Hat tip to the NWS Green Bay for providing the information on which icebreaker was involved. Finally, a look to the southern portion of the overpass: the Mississippi River, between the states of Louisiana and Mississippi. The Landsat satellites fly over the same portion of the Earth every 17 days, so taking advantage of this fact we can visualize the profound changes in the southern Mississippi River due to the flow of large amounts of water resulting from heavy rainfall farther to the north — over the Middle Mississippi River and Ohio River Valley regions — during December 2015 (as discussed in this blog post). Water appears as darker shades of blue in these particular Landsat RGB images, aiding in the identification of areas where flooding is occurring.