The team of scientists led by Susannah Burrows and Daniel McCoy from the University of Washington attempted to differentiate among the multiple types of aerosols and identify the role of organic matter in cloud formation.
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As per the oceanic and atmospheric circulation in the Southern Hemisphere, these clouds may also help understand how sensitive our planet is to accumulation of greenhouse gases.
Satellites use chlorophyll’s green color to detect biological activity in the oceans. The study stems from the research teams of the Pacific Northwest National Laboratory and the University of Washington.
“The clouds over the Southern Ocean reflect significantly more sunlight in the summertime than they would without these huge plankton blooms”, Daniel McCoy, study co-author said.
A recent study of clouds over the most remote ocean have shown that ocean life are responsible for nearly half of the cloud droplets which come in & out of existence in summer.
The effect creates some definite energy: For instance, the increased brightness caused by the tiny sea life reflects about 4 watts of solar energy per square meter, the report says, according to the release.
“This idea has been floating out there as a hypothesis, but there hasn’t been much evidence”, said cloud expert Robert Wood, a UW professor of atmospheric sciences. The space agency launched the first Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument in 1999 to measure the cloud droplet size for all Earth’s skies.
Thus, the Southern Ocean plankton holds the key for cloud droplet formation. As for organic aerosols, this was a harder task for Burrows and McCoy’s team, and they ended up using a separate model simulating organic matter within sea spray, instead of within aerosols.
The new study looked more closely at what else might be making the clouds more reflective. Indeed, this region, considered by scientists one of the cloudiest regions on Earth, may owe the blankets of clouds overhead to tiny marine organisms called phytoplankton.
Marine life has effects on clouds. As organic matter brimms at the surface of the Southern Ocean, the wind picks it up and stirs it through the air, adding to the organic component of bright cloud formation. Marine organisms produce aerosols too but most evaporate.
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The Southern Ocean is a unique environment for studying clouds. “Really the marine aerosols are running the show there”. And with the aerosol data duly simulated, they discovered it was quite similar to actual cloud droplet data. “It also provides a glimpse of how a pristine, pre-industrial area might behave”.
