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Mon September 24, 2012
Video: Plenty of superior mirages this summer – here's a great one
Greg Johnson, a Puget Sound weather aficionado, was recently called out by KPLU’s own weather expert Cliff Mass for a unique video that shows the development of superior mirages during the day. And, with our string of sunny days, there has been plenty of opportunity to see the mirages this summer.
Mass wrote in his blog post on Johnson:
The Puget Sound area is one of best for viewing superior mirages, mirages in which objects near the surface are expanded or projected upwards, occasionally even being inverted.
We are fortunate to have a wonderful mirage observing location: The weather station and multiple web cams run by Greg Johnson of Hansville, who supports a marvelous website that is hugely popular among the region's weather lovers.
His location, on the water along the north side of the Kitsap Peninsula, affords a unique view of mirages …
Below is a time-lapse video made from 2,417 high-resolution photos Johnson took over the day on Sept. 7, one of the hottest days on the Sound this summer (worth watching on full screen):
Johnson told KPLU that he sees superior mirages frequently from his home-based weather station when looking or pointing a camera north in the direction of the Bush Point Lighthouse because of the cold water coming into the Sound.
He says to notice how the height over the water where the mirages are occurring grows as the day progresses. The mirages start at water level and end with the mountains in the background distorting.
Superior mirages are most frequent during our summers near one of the water bodies (Puget Sound, the Straits of Georgia/Juan de Fuca, the Pacific) for a good reason: They are dependent on the existence of a large temperatures differences (increases) above the surface. In this case with cold water near the surface chilling the surface air, and much warmer air above, resulting in a strong inversion. …
Cold air near the surface is more dense than the warmer air above, and the change in densities create a lens-like effect in the atmosphere that produces the mirage.
On the Web:
Summer of 2012