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Old 04-19-2019, 06:24 PM   #109
DickR
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Quote:
Originally Posted by 8gv View Post
At the risk of being "that guy", I believe that the fog may be a result of the ice going away, not the cause of it.

Can someone set me straight on this belief?
It's both. The fog forms close to the ice because the layer of air there is cooled below the dew point of the bulk air mass over us, which (for Moultonborough at 6:19pm) is 60 F. But the moisture in that somewhat humid air also is condensing at the ice surface, giving it about 1000 BTU/lb of moisture condensed. Compare that to about 143 BTU/lb of ice melted, and you have close to seven pounds of ice melted per pound of moisture condensed out of the air. Think of the ice as being a dehumidifier for the air. You wouldn't notice the fog if there were any wind, as that would keep the air layers mixed, but the rate of melting would be even higher. The mixing would bring the energy in the warmer, somewhat humid air to the ice surface faster.
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