I posed a little problem in yesterday's post. How high is the contrail? I had no takers so here's the solution.....
The city of Washington DC is outlined in the image. Looking up the size of Washington it is 176 sq km. so my guess is that it is about 20x10 km give or take a couple. So eyeballing the offset of the contrail shadow from the contrail it is about 20 km.
It was December 22...winter solstice + 1 day....hmmm....that means the Sun is right over the Tropic of Capricorn or 23 degrees south. Our latitude is 39 N so the sun's angle is 39+23 degrees or 62 degrees from the zenith. The tangent of (90-62) degrees is the height of the contrail over the offset distance. Tan (28) * 20 km = 10.6 km. A reasonable height for the contrail.
If we'd had the lidar running yesterday, we could have measured it more accurately. Anyone want to take a stab at the lower cloud in today's image?
Geometry's fun.
Posted by Ray Hoff at December 23, 2005 7:51 PM