Yesterday we were asked how high is the cloud in MD, given the solution for determining contrail height on Dec 22. So much running around in preparation for the holidays I did not get chance to read and give a response to the first question.
Well, let me have a go at it, even though I wont get any extra credit ;-) …
But before I begin let me refresh everyone's memory of yesterday's TERRA MODIS image. I will calculate the height of the cloud nearest to Washington D.C., which is pointed to by a red arrow. With some help from mapquest I determined that this cloud was in Wheaton MD and the cloud shadow was near Aspen Hill MD. Thus the offset of the cloud shadow from the cloud is ~ 5 km.
Since it is only two days from winter solstice I will argue that the suns position is still 23.5 degrees South latitude. The latitude of Rockville is 39.083N, similar to the contrail problem. So then the cloud height is…
TAN [ 90- (39.083N + 23.5S) ] = 0.51872
0.15872*5km =2.29km ~3km
The boss was indeed right this is a low cloud.
Please stay linked to the blog for an update on the nations air quality!
