Quiz Time: What county in the USA has all boundaries visible from satellite?
MODIS-derived (from Terra and Aqua satellites) Bidirectional Reflectance Distribution Function (BRDF), above, (as noted in this blog post), shows the (meager) snow distribution as of early December. How many counties (or parishes) in the United States (out of more than 3000!) are clearly delineated in Satellite Imagery such as what is shown above? Counties that are primarily islands (or peninsulas) — Dare County in North Carolina, for example — show up well (False Color image shown here, in an image taken from VIIRS Today), but the inland borders do not.
For a county to be recognizable from Space, its landcover must differ significantly from adjacent counties. In the zooming-in animation below (from RealEarth, click the image to zoom in), users will note that Menominee County in northeast Wisconsin becomes apparent. Menominee County is almost entirely forest (unlike its neighbors) and as such has a much different signal in the (for example) 0.87 µm channel on VIIRS (or 0.86 µm on GOES-16). When it is zoomed in, the outlines of the County are obvious.
The county also shows up well in the VIIRS True Color/False Color toggle below, from 30 November. The southern edge of the snow at that time was just southeast of Menominee County, and the land-use change across the county border is apparent. Snow in the county (cyan in the False Color enhancement) is difficult to view from the imagery — because of the pine forests!
Menominee County has been on this blog before! In 2007, a tornado tracked through Menominee County and left a visible scar in satellite imagery (link). Eight years later (link), the scar was still apparent! November 6 2021 was a clear day over the upper Midwest. Suomi-NPP True Color imagery, below (link to original large image), still shows vestiges of the scar!
