Marine stratocumulus clouds are relatively low in height (below about 1.6 kilometers or 1 mile) and are usually too large to be fully observed from below. But observations from above by satellites orbiting hundreds of kilometers above Earth’s surface have revealed the impressive coverage of these clouds as well as their fascinating shapes and patterns.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra and Aqua satellites have helped meteorologists determine that marine stratocumulus clouds are relatively common. On average, they cover about 23 percent of the world’s oceans, or about 15 percent of Earth’s total surface area.
Organized marine stratocumulus clouds, which are a subcategory of marine stratocumulus clouds found in the mid-latitudes and subtropics, take two forms: open cells and closed cells. Open cell clouds appear as thin wisps around empty air pockets (“cells”) and do not block much of the Sun’s radiation. Closed cell clouds appear denser and puffier without open centers, which allows them to reflect more solar radiation back into space. , Both types of clouds are caused by patches of warm air that rise, expand, cool, and condense into tiny visible droplets of liquid. In open-cell clouds, cold air sinks into the empty center while warm air rises above the edges; In closed-cell clouds, warm air rises in the center and cold air sinks at the edges.
It may sound counterintuitive, but it is open cell clouds that produce precipitation, while closed cell clouds produce little or no precipitation. This contributes to the tendency of open cell clouds to break up within a few hours, while cirrus clouds can retain their shape for up to half a day. Closed cell systems are also more likely to form in cooler areas of the ocean, while open cell systems are more likely to form in ocean areas with stronger circulation.
Recent studies have shown that local air quality can affect the formation of open and closed cell clouds. Smoke and dust particles, and aerosols from ships and factories can initiate an infection between these types of clouds.
On August 25, 2022, the MODIS instrument aboard NASA’s Terra satellite obtained this image (top) of open and closed cell clouds about 1,600 kilometers (1,000 miles) west of the Chilean coast. According to the scientists, the closed-cell cloud systems depicted here appear roughly triangular in structure, and they tend to be larger than lower-atmosphere cellular cloud systems. This may be due to atmospheric instability, precipitation, or other variations in the atmosphere over this region of the Pacific Ocean. The images for the video of the photographic sequence were obtained that day with the Advanced Baseline Imager (ABI) on board the Geostationary Operational Environmental Survey Satellite 17 (GOES 17). GOES 17 is operated by the National Oceanic and Atmospheric Administration (NOAA); NASA is helping to develop and launch the GOES series of satellites.
On August 25, large open cell and similar-looking closed cell cloud banks dotted the west coasts of North and South America. The west coasts of continents are particularly favorable for the formation of these cloud banks because ocean temperatures are lower relative to other regions at the same latitude, and the atmosphere is more stable near large land masses.
Over the next few days, MODIS observed new pockets of open and closed cell clouds forming and dispersing off the coast of South America. A better understanding of the size and formation of cloud systems in the lower atmosphere contributes to our ability to better predict weather and improve the accuracy of climate models.
NASA Earth Observatory image and video by Joshua Stevens using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview and data from the GOES 17 satellite from NOAA and the National Environmental Information Center (NCEI). Reporting by Hannah Richter, with reporting by Terence Kuber (NASA’s Jet Propulsion Laboratory).
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