Monday, September 20, 2010

An Essex Mirage

Unusual atmospherics this afternoon, as for the first time in my living memory at least, one can just about make out the Essex coast from the promenade at Westgate.

Even more curiously, while readers may easily see the windfarms opposite Whitstable and North Foreland, unless you happen to be a pilot, you wouldn't necessarily know there's another large windfarm just south of Clacton, over 25 nautical miles away.

With the curvature of the earth at 11 miles, the Essex coast and the Clacton windfarm should be quite invisible to the naked eye but I can just about make out a fuzzy line of white objects exactly where the Essex array should be.

Clearly it's something to do with the temperature of the air and the sea forming a lens but having lived here since I was a boy, I've never observed anything quite like it.

NB: A superior mirage occurs when the air below the line of sight is colder than that above. This is called a temperature inversion, since it does not represent the normal temperature gradient of the atmosphere. In this case the light rays are bent down and so the image appears above the true object, hence the name superior

1 comment:

Peter Checksfield said...

I noticed the Essex wind farm from the back of The Winter Gardens (for the first time) about 2 weeks ago, so we must've had similar conditions then.