For more information on distinguishing low clouds, click the link at the bottom of this page. This link will open "Remote Sensing of the Land, Oceans, and Atmosphere with MODIS," a Webcast that details the capabilities of the MODIS instrument on the Aqua and Terra satellites. The link will open in the "Land Application Examples" section. Click the "Cloud Classification" page on the left menu bar for an explanation of different thresholds for classifying clouds and surface features.