Saturday, December 13, 2014

Lessons in Fluid Dynamics!

The other day we again transited the country, flying to Chicago to visit family and friends at "Ketelsen East". Another uneventful trip, with my nose pressed against the window. I saw something today on the Interweb that prompted me to do this post - more on that in a minute.

As sort of an introduction, I've always enjoyed the views from mountaintops. The reasons observatories are built there is that many detrimental effects occur at lower levels. One of the first things you notice, particularly at this time of year when inversion layers form and trap haze and pollutants at lower levels, is that the mountains poke above these layers into clearer air. It wasn't 5 minutes after takeoff that the Whetstone Mountains short of Benson (at left)were seen sticking above the haze trapped from there down to Sierra Vista and the Huachuca Mountains at distant center. In this case, and likely all the others shown here, warm air above traps cooler air (and particulates) near the ground.

Not far across the border in New Mexico, even before we had reached our cruising altitude, I spotted an interesting cloud formation far below us.  Checking times and Google Maps, it appears to be ground-hugging clouds between the Pinos Altos mountains at bottom center and the Black Range at upper left.  Here again, the cooler, moister air appears to be filling the canyons and valleys in the mountains.  It seems amazing that giant cloud formations miles long can form these serpentine shapes following the terrain of the mountains.  It demonstrates the fluid properties of air and the material it carries along.  The right image is a closer view of the left edge of the left frame as we passed over.

I've seen some spectacular time-lapses demonstrating the fluid properties of clouds - "Vancouver City" comes to mind, as does "Island in the Sky".  If you have a few minutes, you REALLY should watch both, in HD, fullscreen, with sound! 

Anyway, all this is a lead-in to the cloud inversion observed at the Grand Canyon 2 days ago (Thursday).  A time-lapse, taken by Michael Quinn for the NPS, compressed 15 minutes of images into a 1 minute video.  Perhaps it is something so familiar to us regulars from the Grand Canyon Star Party looking so unusual that catches our eye, but the fluid properties of the clouds looks so much like waves rushing against a rocky beach. I'm not sure where this was taken, but I've seen some of his other images taken from Mather Point, so it might well have been taken there looking SW towards Yavapai Point, a couple hundred yards from where we set up in June.   No sound on this one, but very fun.  Enjoy!

1 comment:

Anonymous said...

Interesting post, as always!! Thanks for talking about the Grand Canyon video- I'd heard about it but enjoyed reading your description! Hope you and Mel are enjoying your time there!

~ Ewica