Encore - Lenticular Clouds Over Wales
March 18, 2017
Today and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.
These stacked lenticular clouds were observed from the A5 Road just east of Tryfan, Wales, in the mountain pass between the Carneddau and Glyderau ranges. Normally found in the lee of mountains, altocumulus lenticularis are a type of stationary wave cloud that results when air is forced to rise over elevated terrain. Water vapor within the wave layer condenses at the wave crest if the temperature is sufficiently cool (dew point temperature), forming a smooth, lens-shaped cloud. The cloud evaporates due to adiabatic heating when it sinks into the drier wave trough. In this way, clouds appear at intervals closely related to the wavelength. Photo taken on June 26, 2011.
Photo Details: Camera Maker: Canon; Camera Model: Canon EOS 500D; Focal Length: 30.0mm; Aperture: f/8.0; Exposure Time: 0.0020 s (1/500); ISO equiv: 100.