Some features of this site are not compatible with your browser. Install Opera Mini to better experience this site.

Cloudy Congo River Basin

Cloudy Congo River Basin

An astronaut onboard the International Space Station captured this oblique photograph while looking southwest across the Congo River Basin. Located along the equator, the area is one of the cloudiest places on Earth. Low-altitude cumulus clouds, sometimes called popcorn clouds, trace the landscape over dense rainforests in this shot.

Note, however, that the skies above the Congo River and its many tributaries are noticeably free of clouds. The river can be up to 5 kilometers (3 miles) wide in many places—enough to deter cloud formation. Warm, humid air rises from the forest and cools as it rises, resulting in the development of clouds. But the river waters—and the air above them—are cooler, so there is less moisture rising into the air. Similar cloud patterns are common in the Amazon Rainforest.

Toward the horizon, larger storm clouds are forming along the Inter-Tropical Convergence Zone. The ITCZ is a broad region of low atmospheric pressure that encircles the Earth near the equator. The ITCZ and its thunderstorms follow the seasonal position of the Sun, such that large storms appear south of the equator during Southern Hemisphere summer (when this image was taken).

Astronaut photograph ISS057-E-58903 was acquired on November 5, 2018, with a Nikon D5 digital camera using a 116 millimeter lens and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 57 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Andrea Meado, Jacobs Technology, and Justin Wilkinson, Texas State University, JETS Contract at NASA-JSC.