Re: Dew Formation

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 01:04 PM 3/13/2004, you wrote:
> >When dew forms on clear nights, it will heavily wet lawns but will
> >hardly ever leave visible moisture on concrete walkways or asphalt
> >roads. There are many factors that regulate condensation:
> >temperature, available condensation nucleii, curvature, hydrophilic
> >surfaces, etc. - but I am having difficulty identifying the  primary
> >one in this case. Any ideas out there?
>
> The primary mechanism is radiation exchange with 2 pi steradians of a
> 3 kelvin blackbody plus high resistance thermal conduction pathways
> to the ground and the (still) air.
>
> --
> John Mallinckrodt        mailto:ajm@csupomona.edu


Then too, if his local roads are like the runways on the training
 airbase here, which are noted to modify the local weather, they may
offer a significant thermal reservoir which holds such surfaces a
little warmer than the local plant life at dawn.


Brian Whatcott    Altus OK    Eureka!