Radiation fog sounds like something that might occur during a nuclear winter, but it’s not that kind of radiation. The radiation here is heat radiation—infrared wavelengths radiated by the ground during the night, particularly when the skies are clear. Usually, the air temperature gets lower as you get higher—a rising packet of air expands and … Continue reading Radiation Fog
At first glance, that’s just some nice sunset cloud over Juan-les-Pins in France. But there’s quite a lot going on in that picture, which you’ll see better if you click to enlarge it. (I’ll post some zoomed views of sections of the whole image below.) The sun has just set, off to the left of … Continue reading Fall Streaks
Crepuscular rays are rays that occur during the crepuscule, which is a fine old word for “twilight”. They’re the rays of brightness and shadow that seem to fan outwards and upwards from the setting or rising sun when it is masked by cloud. What’s happening is that the shadow of the clouds is being projected … Continue reading Crepuscular Rays