As sun angles are low where ice fog occurs, radiational cooling
of the fog tops is a significant factor, allowing the cold layer to deepen and cool over days.
And you'll want to bundle up in blankets or a sleeping bag and a winter hat even in summer; it gets surprisingly cold under a clear, wide-open sky late at night due to radiational cooling
A sleeping bag provides further protection from the late-night radiational cooling
under a clear sky.
Part of the Kyushu region in southern Japan saw the mercury fall close to freezing point due to the radiational cooling
effects of the cold air, while the agency issued heavy snow warnings for Aomori, Akita and Iwate prefectures in northeastern Japan.
Looking at the starlit night, Pete remembered that if the sky is cloudless, radiational cooling
occurs when warm air escapes the earth.
The agency said the chilly weather was due to a phenomenon called radiational cooling
, which is the cooling of the earth's surface and adjacent air whenever the earth's surface suffers a net loss of heat due to terrestrial radiation.
Several basic cooling methods lend themselves to amplifiers or other operational electronics, including passive cooling (operating in a cold environment), radiational cooling
, using heat pipes to a cold sink, active cooling using liquid nitrogen refrigerant (or some other super-cooled liquid) and electrical junction cooling (a Peltier cooler or the like).
Nighttime fog is a major problem, occurring at any location where there's strong radiational cooling
and ground moisture.
Our nights are generally very humid, and radiational cooling
can quickly drop the temperature of exposed optical surfaces below the dew point, causing them to fog up.
The second problem is that you're watching in the night's coldest hours in the year's coldest time, under a wide-open clear sky that will also expose you to maximum radiational cooling
is a powerful mechanism for increasing relative humidity by dropping the temperature.
A clear sky means radiational cooling
, and a wide-open sky exposes you to the most radiational cooling
possible (and wind).