Scientists are constantly looking for creative ways to slow global warming, and now they're turning their attention to the sky. While most San Diegans prefer a sunny day at the coast, local researchers say the cloudier days work to their advantage when studying how clouds and particles interact.
”Aren’t we glad that they’re here? Because how hot would it be if they weren’t here," Lynn Russell, a professor of atmospheric sciences at Scripps Institution of Oceanography at the University of California, San Diego, said Friday.
She's referring to the cloudy days that San Diego can often see throughout the year, commonly coined as "June Gloom" or "May Gray." While many may not love marine low clouds, Russell does, and she studies them.
"We actually think that’s an advantage because you can have this effect with the particles and it will keep cooling for a while," Russell said.
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While the clouds block our sunshine, they were the focus of a 12-month research cycle to find out how clouds and particles interact.
"This inlet and instruments were up at Mt. Soledad all year," Russell said describing the location where data was collected. "And we had a number of instruments down at the pier."
Jeramy Dedrick, a Ph.D. candidate at Scripps, says part of that research included sizing and counting the number of particles that came through the air through a tube connected to the inlet.
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”We want to understand the number and the size of the particles in the air," Dedrick said.
Russell says one inlet that brought in cloud droplets is helping researchers understand the effects of these particles on clouds. More than 700 hours of cloud droplet measurements were collected, Russell says. Understanding this interaction is important and could lead to more answers when it comes to what's called marine cloud brightening.
”Marine cloud brightening is the idea of enhancing the natural effect of clouds by making them reflect more sunlight," Russell said.
The brighter something is, the more it will reflect light.
"The idea is to enhance that effect and make them even brighter than they would be naturally, and it turns out that that’s sort of already happening for us in some places because pollution tends to make clouds brighter because it makes the droplets in the clouds smaller," Russell explained. "And then you get more of them, and that makes them look whiter than they already work."
Russell added that the marine low clouds that sometimes sock in our coastline rarely produce rain and they stay put, which is an advantage to the research she does locally. A recent study co-authored by Russell and several other scientists from NOAA and other scientific organizations proposes more research and testing would need to be done to examine marine cloud brightening.
According to the abstract of the study, in order to better understand marine cloud brightening, a targeted program of research, including field and laboratory experiments, monitoring and numerical modeling, needs to be done.
"We need more information on whether this idea of adding simple particles is going to work," Russell said.
So, how would researchers brighten clouds?
Sea salt spray is one option.
”There are ideas that involve atomizing a bunch of salt water and cleaning it up and emitting that into the atmosphere, and you’d have to do that over long stretches of space and time over the ocean in order to have a big enough impact," Russell said.
For now, there needs to be more research done, which is why scientists aren't doing this work yet. Blatantly put, Russell says it needs to be tested to see if it works.
"Brightening clouds is not a solution to climate change. It can only be used in conjunction with mitigating carbon because it will only last for a little while. It only offsets a little of the carbon," Russell said.
