Weather satellite image from this morning

This morning's 3-micron ("water vapor") image from the NOAA-18 polar orbiter.  This particular spectral band is very useful for discriminating ground fog from the image background, especially when considered along with the visible and infrared imagery.  Fog and other cloud types composed primarily of water vapor (rather than ice crystals), show up in dark gray.  Northernmost Greenland, including Thule and the Zachariae and 79N Glaciers, is almost completely clear in this image.  All other science targets from Thule are socked in.