Image: Afternoon Clouds over the Amazon Rainforest

Description: This image reveals how the forest and the atmosphere interact to create a uniform layer of “popcorn” clouds one afternoon. During the dry season, the rainforest gets more sunlight. The plants thrive, putting out extra leaves and increasing photosynthesis. The photosynthesising plants release water vapour into the atmosphere. Water vapour is more buoyant than dry air, so it rises and eventually condenses into clouds like the popcorn clouds shown in this image. These clouds are almost certainly a result of transpiration. The clouds are distributed evenly across the forest, but no clouds formed over the Amazon River and its floodplain, where there is no tall canopy of trees. When water vapour condenses, it releases heat into the atmosphere. The heat makes the air even more buoyant, and it rises. The higher it rises, the more the air expands and cools, which allows more water vapour to condense. Eventually, thunderstorms can form. The more concentrated clusters of clouds in the image are likely thunderstorms.
Title: Afternoon Clouds over the Amazon Rainforest
Credit: NASA Earth Observatory
Author: Jeff Schmaltz
Usage Terms: Public domain
License: Public domain
Attribution Required?: No