In this week’s Imaggeo on Mondays, brought to you by the photographer himself, Lukas Hörtnagl (University of Innsbruck, Austria) tells us about the ‘blue haze’ or ‘tule fog’ of California’s Sequoia National Park.
I was visiting the United States to attend the Fall Meeting of the American Geophysical Union in December 2011 and decided to stay four more weeks to visit some of the National Parks in California, Arizona and Nevada. Soon, it was obvious that each park seemed eager to look its best on camera. California’s Sequoia National Park was no exception.
This photo was taken in January 2012 while driving down the Generals Highway — a road that crosses the National Park and is named after two of its most famous trees, the General Sherman and General Grant sequoias — looking west/south-west at the western borders of the park. Further in the background is the Great Central Valley in California.
The thick ground fog visible in the photo is called ‘tule fog’ and typically forms during the winter months when longer nights result in an extended period of ground cooling. The combination of relatively high humidity (e.g. after rain events) and the loss of heat by radiation can lead to the formation of this fog, which can last for days. While the fog layer is cold, the air directly above is typically warm and — as you can see in the picture — clear. However, the visibility down in the valley was much better than it seemed from above.
By Lukas Hörtnagl, Biomet Innsbruck
Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their images to this repository and since it is open access, these photos can be used by scientists for their presentations or publications as well as by the press and public for educational purposes and otherwise. If you submit your images to Imaggeo, you retain full rights of use, since they are licensed and distributed by the EGU under a Creative Commons licence.