Surface Water Freezing: Can It Happen?

[mike2007]

Is it possible for water on the surface of a road to freeze even though the temperature of the air just above the road is above 0 degree celsius?

I think the answer is yes but i do not have any theories to support it.
It may be because the air above is is above 0 degrees so it tends to rise and the cooler air flows downward towards the road and thereby the road freezes.

 

[Feynman diagram]

The temperature of the ice will be affected far more by the temperature of the ground than the air above it.

 

[Astronuc]

Is it possible for water on the surface of a road to freeze even though the temperature of the air just above the road is above 0 degree celsius?

Yes. One may have noticed signs in some parts of the country warning that the bridge will freeze before the road way. This is because the bridge structure is colder than the road or air. The water freezes on the bridge, which is below freezing.

In a prolonged cold environment, the ground may cool below freezing. Even when the air is warmer, if the ground is below freezing, then moisture could freeze on the ground.

One has to look at the heat sinks and sources, and the flow of heat.