On 04/02/11 14:41, Jim Thompson wrote:
Something I've not seen before here in AZ...

Looking out, I noticed the pool looked odd this morning, went out
(7:40AM, presently 30°F)...

A thin skim of ice on the eastern half!

I've heard the Romans and Arabs used to make ice by exposing water to
the desert sky at night, covering it in the day. After a few days'
cycling it had radiated enough heat into the clear desert sky to freeze.
Doesn't work in areas where there are clouds at night.