sublimation and deposition

[cessna 150]

good evening people, I just have 1 quick question for you guys and I just need confirmation. In From the Ground up, it say's deposition is from gas to solid and sublimation is solid to gas and that seems right. In the Air Command Weather Manual they call both the processes sublimation and at first I was wondering if it was a mistake on that 1 page but gas to solid and solid to gas are referred to as sublimation on every page that brings up these processes in that book.

So I am pretty sure it is deposition and sublimation and not just sublimation but I just need confirmation.

Thanks!

[Dust Devil]

http://en.wikipedia.org/wiki/Deposition_%28physics%29

[cessna 150]

Okay thanks, just needed confirmation because the weather manual is a very good book and I just needed to double check.

[loopa]

And now think of it this way c150,

If something doesn't become a liquid before freezing, or rather goes through deposition, will this type of air parcel be of importance for icing conditions and should precautions be made for it? Or another way to ask this is, what is the main difference between supercooled water droplets (precautions necessary) and ice crystals (no precautions)... ?

Or also in other words, why is it that anti ice systems are not required when flying through cirrus clouds up at FL350?

See if you can answer these questions, anybody else is welcome too do so as well

[cessna 150]

hmm....anti ice equipment is not required with flying in cirrus clouds because the higher up you get the less water vapor there is and the colder the temperature is and so since warm air holds more water vapor then cold air that would mean there is little to no water vapor in the cirrus clouds. Precautions are necessary for super cooled water droplets and not ice crystals because when the water droplet strikes the aircraft skin it freezes which releases latent heat and that in turn warms the atmosphere around the drop which then makes it freeze slower and so it can spread on the aircraft. No precautions are needed for ice crystals because.....since you are at FL350 your aircraft skin may be colder then the ice crystal it self and so when the ice crystal strikes the aircraft skin it will not stick to the aircraft but rather just bounce off for a lack of better words but if your aircraft skin is warmer then the ice crystal, then you may pick up icing.

Right?