Undulatus Asperatus Clouds

August 22, 2011

Undulatis_ArgentinaIMG_8317-16c_eb (2)

: Luis Argerich; Luis's Website
Summary Author: Luis Argerich; Jim Foster

August 2011 Earth Science Picture of the Day Viewer's Choice

The photo above shows unusual looking clouds looming over a lagoon near Lobos, Argentina. This formation appeared, oddly enough, following a morning storm. The clouds are referred to as undulatus asperatus, a recently introduced cloud designation (2009). These roughened wave clouds may be related to a type of altostratus cloud -- altostratus undulatus. It seems that Undulatus asperatus have a predisposition to form before midday, over relatively flat terrain and after convective storms have passed by. Though these intriguing clouds made the sky look especially threatening, no precipitation or strong winds ensued. They persisted for several hours before finally dissipating. Photo taken at approximately 10:00 a.m. on August 23, 2010.

Photo details: Camera Maker: Canon; Camera Model: Canon EOS 40D; Focal Length: 17.0mm; Aperture: f/8.0; Exposure Time: 0.0016 s (1/640); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: Manual; Exposure Mode: Manual; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB.