Rippled stratus clouds over pack ice, Ross Sea, Antarctica

The seas around Antarctica are frequently ice-covered, even in midsummer, and consequently there is little opportunity for the air at the surface to be warmed to any great extent because much of the sun’s energy is reflected back out into space by snow and ice. For this reason the atmosphere is usually very stable in these latitudes, with very little convection; flat or layered clouds such as stratus are therefore very common compared with the bubbly cumulus clouds more commonly seen at lower latitudes where the land or ocean surface is comparatively warmer than the air above it.

This low stratus cloud over pack ice was photographed in the Ross Sea off the Antarctic Coast at about 3 a.m. on a midsummer’s night. There was no wind at the surface at the time I took this photograph but the rhythmic rolls of cloud showed that there was some wind blowing at higher altitudes, setting up a series of waves in the bottom layer of the atmosphere and so causing the cloud layer to take on this striking rippled pattern.