Cloud Fraction

In some parts of the world the difference in the amount of clouds over land versus ocean is so stark that the outlines of continents and other landmasses can be traced through observations of clouds alone. This image of October 2009’s cloud fraction (the fraction of an area covered by clouds) demonstrates the pattern. The measurements were collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Colors range from blue (no clouds) to white (totally cloudy). -- Earth Observatory