Across vast reaches of open ocean at any one time is a low-lying cloud level that takes on a captivating pattern of more-or-less hexagonal cells -- like a honeycomb, or Grandma's quilt. What is this pattern? And why do these "cells" close up in one place and open somewhere else?
To climate scientists, these are not idle questions. Clouds are one of the most difficult problems in climate science -- they give modelers fits -- and patterns such as these in the stratocumulus layer over the oceans play a role in how much warming sunlight heats the ocean and how much strikes the bright cloud top and reflects back into space.
Researchers led by physicist Graham Feingold of the National Oceanic and Atmospheric Administration report in the new issue of the journal Nature that they can now explain this pattern of oscillating open and closed cell structure. The overall pattern is indeed composed of individual convective cells that build up and open as the rain falls, leaving the cell walls intact. The downdraft splays out along the ocean surface, colliding with neighboring downdrafts and forcing new upward air momentum…and so it goes.
At the Department of Energy's Pacific Northwest National Laboratory in Richland, WA, co-author Hailong Wang said their ability to simulate the behavior of these clouds in computers "will help us to better interpret measurements in the real atmosphere and represent these clouds in climate models."
The researchers say they have also shown for the first time that these open-cell clouds behave like other self-organizing systems, such as flocks of birds and shifting sand dunes, that "form dynamic, coherent structures that tend to repair themselves and resistant change."
Image: NASA's Aqua satellite captured this cellular pattern over the southeast Pacific off the coast of Peru. (Click on the image and see how it fits into a bigger picture.)
To climate scientists, these are not idle questions. Clouds are one of the most difficult problems in climate science -- they give modelers fits -- and patterns such as these in the stratocumulus layer over the oceans play a role in how much warming sunlight heats the ocean and how much strikes the bright cloud top and reflects back into space.
Researchers led by physicist Graham Feingold of the National Oceanic and Atmospheric Administration report in the new issue of the journal Nature that they can now explain this pattern of oscillating open and closed cell structure. The overall pattern is indeed composed of individual convective cells that build up and open as the rain falls, leaving the cell walls intact. The downdraft splays out along the ocean surface, colliding with neighboring downdrafts and forcing new upward air momentum…and so it goes.At the Department of Energy's Pacific Northwest National Laboratory in Richland, WA, co-author Hailong Wang said their ability to simulate the behavior of these clouds in computers "will help us to better interpret measurements in the real atmosphere and represent these clouds in climate models."
The researchers say they have also shown for the first time that these open-cell clouds behave like other self-organizing systems, such as flocks of birds and shifting sand dunes, that "form dynamic, coherent structures that tend to repair themselves and resistant change."
Image: NASA's Aqua satellite captured this cellular pattern over the southeast Pacific off the coast of Peru. (Click on the image and see how it fits into a bigger picture.)
Tags: Climate Change, Geophysics, Global Warming, Meteorology, Oceanography
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