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Closed Small Cell Clouds in the South Pacific
This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science. However, more recent observations and studies may have rendered some content obsolete.
The structure of tightly packed ‘closed cells’ in a layer of marine
stratocumulus over the southeastern Pacific Ocean are highlighted in these views
from the Multi-angle Imaging SpectroRadiometer (MISR). Closed cell clouds are formed
under conditions of widespread sinking of the air above. As heat is radiated to
the atmosphere, the top of the cloud cools. The cool air sinks along the cell
boundaries and this sinking motion perturbs the shallow cloud layer into
interesting structures such as those shown here. These cells are notably small,
with diameters ranging from 10-15 kilometers, instead of the 15-45 kilometers
typically noted in satellite observations. The dark areas along the cell
boundaries are also cloudy and do not indicate clear sky. Closed cell clouds are
found in high pressure systems characterized by weak winds, and are thought to
occur preferentially over cold ocean waters. The image covers an area of about
280 kilometers x 227 kilometers.
An overview image showing some of the meteorological context, and a
natural-color and inverted image pair are also provided. The cell structure and
the distinctive radial patterns indicative of the sinking air motions are easier
to see clearly in the inverted view. The area covered by the overview on the
left is 274 kilometers x 463 kilometers, while the right-hand images each cover
278 kilometers x 62 kilometers. All of the images were created with data from
MISR’s vertical-viewing (nadir) camera, and were acquired on November 19, 2001
(during Terra orbit 10228). The scenes are centered roughly at 38 degrees south
latitude and 118 degrees west longitude.
Low-lying marine stratocumulus clouds are important components in the Earth’s
energy budget because they are bright and abundant, and reflect a large amount
of solar energy toward space. They are difficult to represent in climate models
however, due to their variable structure and rapid changes in reflectivity over