Salty sea spray affects the lifetimes of clouds, researchers find

December 21, 2015

All over the planet, every day, oceans send plumes of sea spray into the atmosphere. Beyond the poetry of crashing ocean waves, this salt- and carbon-rich spray has a dramatic effect on the formation and duration of clouds.

Yes, clouds, which cover 60 percent of the Earth's surface at any given time. In a new study in Proceedings of the National Academy of Sciences, online Dec. 21, Colorado State University's Paul DeMott, a senior research scientist in the Department of Atmospheric Science, says sea spray is a unique, underappreciated source of what are called ice nucleating particles - microscopic bits that make their way into clouds and initiate the formation of ice, and in turn affect the composition and duration of clouds.

"The presence of these particles is critically important for precipitation and the lifetime of clouds, and consequently, for their radiative properties," said DeMott, who works in the lab of Sonia Kreidenweis, professor of atmospheric science, associate dean for research in the College of Engineering and a University Distinguished Professor.

Clouds' effect on climate

Clouds, with their ability to reflect solar energy and absorb terrestrial radiation, have dramatic effects on climate. Their radiative properties are greatly influenced by the number, size and type of droplets and ice particles inside the cloud. These cloud particles can initiate from any number of sources of aerosols - particles suspended in air - from land and ocean surfaces. From desert dust to burning fossil fuels, aerosols that affect clouds are everywhere.

DeMott's study has confirmed that ice nucleating particles from oceans are distinct, both in their abundance as well as their ice-making properties, from land-sourced particles. Hence, their influence on the liquid/ice phase structure of clouds, and their subsequent radiative impacts, can differ over vast swaths of Earth.

Center for Aerosol Impacts on Climate and the Environment

The laboratory portion of the study was conducted with other researchers at the National Science Foundation-supported Center for Aerosol Impacts on Climate and the Environment (CAICE), at which DeMott is a senior scientist. Based at University of California-San Diego, CAICE boasts the world's most cutting-edge laboratory wave flumes that simulate closely how ocean waves send sea spray aerosols into the air. In turn, the researchers can study the biological and chemical makeup and transformations of these particles, and using specialized instruments, how they influence cloud formation. DeMott and colleagues compared these data to other measurements made over oceans.

The study offers one hypothetical explanation for why global climate models have consistently underestimated reflected, short-wave solar radiation in regions dominated by oceans, particularly in the southern hemisphere.

"Our paper gives a clearer picture of the behavior of major classes of atmospheric aerosols in cold clouds - factors that need to go into global-scale climate modeling," DeMott said.

Added Nick Anderson, program director in the National Science Foundation's Division of Atmospheric and Geospace Sciences, which funded the research: "The development of clouds and precipitation is a core issue for understanding weather and climate processes. By studying ice nuclei, which can be considered a building block for clouds, these researchers will help piece together the puzzle of how clouds and precipitation form, especially over remote oceanic regions."
-end-


Colorado State University

Related Aerosols Articles from Brightsurf:

Reducing aerosol pollution without cutting carbon dioxide could make the planet hotter
Humans must reduce carbon dioxide and aerosol pollution simultaneously to avoid weakening the ocean's ability to keep the planet cool, new UC Riverside research shows.

NASA's Terra highlights aerosols from western fires in danger zone
The year 2020 will be remembered for being a very trying year and western wildfires have just added to the year's woes.

NOAA-NASA Suomi NPP captures fires and aerosols across America
On Sep. 07, 2020, NOAA/NASA's Suomi NPP satellite provided two different views of how fires are affecting the US.

Low humidity increases COVID risk; another reason to wear a mask
University of Sydney study confirms a link between COVID-19 cases and lower humidity.

Summer observation campaigns to study pollution in the Asian tropopause layer
Scientists find the aerosols in the boundary layer are mostly pollution out of human activities, and the aerosols in the upper troposphere may also contain natural aerosols, like mineral dust and volcanic sulfate aerosols,

Masks reduce airborne transmission of SARS-CoV-2
Growing evidence suggests that SARS-CoV-2, the novel coronavirus that causes COVID-19, can be spread by asymptomatic people via aerosols -- a reality that deeply underscores the ongoing importance of regular widespread testing, wearing masks and physical distancing to reduce the spread of the virus, say Kimberly Prather and colleagues in a new Perspective.

Fire aerosols decrease global terrestrial ecosystem productivity through changing climate
Cooling, drying, and light attenuation are major impacts of fire aerosols on the global terrestrial ecosystem productivity.

Study: Aerosols have an outsized impact on extreme weather
A reduction in manmade aerosols in Europe has been tied to a reduction in extreme winter weather in the region.

Agricultural area residents in danger of inhaling toxic aerosols
Excess selenium from fertilizers and other natural sources can create air pollution that could lead to lung cancer, asthma, and Type 2 diabetes, according to new UC Riverside research.

Satellite tracking shows how ships affect clouds and climate
By matching the movement of ships to the changes in clouds caused by their emissions, researchers have shown how strongly the two are connected.

Read More: Aerosols News and Aerosols Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.