Anybody have a best memory?

For me it was when I was about 7 or 8, I looked out the car window and saw clouds take the exact shape of a desert oasis! It was unblieveable, pal trees, sand in front, little pool of water. Was a perfect shape! and it wasnt even cumulus clouds that did it, they were stratus.

Thats my best memory. What are yours?

For many years I have been interested in and looking at sedimentary features. Ripples in the sand have always been a favorite. One afternoon here in Maine while in a supermarket parking lot, I looked UP, and the SKY was full of ripples--all ripple clouds.

I asked myself, I said, "Stu, how is this possible? Are these clouds formed in a similar way as sand ripples?"

I became CAS member #24356 and have been happy ever since.

I have very poor retrieval abilities unless I'm given some sort of clue. I just don't find it easy to pluck memories out of thin air (forgive the pun). I would blame middle age, but I've always been like that. So, I'm sure there are lots of earlier cloud experiences just waiting to spring out, but one memory takes me back to being in my late teens, on an outing with friends. We'd had a great summer's day on the hills in Northumberland, and spent the whole of the journey back spotting fantastical shapes in the clouds. A real high, without the drugs. True happiness.

Anita, North Cumbria, UK

I had no idea what kind of clouds they were, but one portion of the sky was filled with lennies, one of which looked like a perfect flying saucer. That was several years ago, and although lenticulars are one of my favorite clouds and I've seen many since, never have I seen one so perfectly formed as that one, with a couple of others coming close to being perfect. Now if I could only see some noctilucent clouds!

I'm no expert - yet - but I think that because stratus cloud and sediments in sand both involve layers, maybe that's why they both can have ripples?

I think the cause of ripples in clouds, sand and water is basically the same thing, shear. When wind blows over the surface of sand or water, the surface grains or molecules move faster than those lower down because of friction. You therefore get a rotation along an axis at right angles to the wind leading to ripples and waves, also at right angles to the wind.

To get the same effect in a layer of cloud, you also need shear but friction is not available as a cause so you need the air at at the top of the layer to be moving at a different speed - and/or direction - to that at the bottom. This will lead to ripples at right angles to the direction of the shear.

I think the cause of ripples in clouds, sand and water is basically the same thing, shear. When wind blows over the surface of sand or water, the surface grains or molecules move faster than those lower down because of friction. You therefore get a rotation along an axis at right angles to the wind leading to ripples and waves, also at right angles to the wind.

To get the same effect in a layer of cloud, you also need shear but friction is not available as a cause so you need the air at at the top of the layer to be moving at a different speed - and/or direction - to that at the bottom. This will lead to ripples at right angles to the direction of the shear.

you said it twice!

Hahaha

Yes, Shakira, I said it twice. Yet another feature of Network54? My first attempt to send a message was reported to have failed so I sent it again. I see "H" also sent a message twice so I assume it was due to the same problem.

You give an interesting answer to how the cloud ripples happen. Thanks.

Why don't cloud formations show ripples more often?

I expect that clouds usually have less rigid layer structure than sand or water because of the variable winds.

But someday I may see ripples above and below me. It would be mighty nice.

The ripple speak reminds me of one of my best cloud memories. During my diamond height badge flight, soaring mountain wave over Aberdeenshire, Scotland. I clipped a lenticular cloud on the way up. While inside the cloud the most amazing optical effects surrounded the sun. All these amazing halos. No picture as I was busy pushing forward against the wind to get out of the cloud before the glider got covered in ice. Once I emerged and climbed above the ripples in the lennies from above made it look like sand dunes in a desert. A did get a picture of that:



Pictures taken at 17-18000 feet. On my way up to 24000 feet, which was as high as I was allowed to go due to airspace above (where transatlantic jets fly).

On the way back down at around 20,000 feet there was this beautiful sight too:



Anyway I'll stop there as older members have seen these pics before...

Fromhttp://piccies.flybywire.org.uk/Gliding/Aboyne2007.html 11th October 2007 - Flight 2 - Crikey over 4 years ago already!

-Mike

nature's aeroplane wings? fantastic shots

Anita, North Cumbria, UK

Yummy pictures. and your dunes have ripples!