BNL’s Ernie Lewis studies clouds to understand climate

BNL’s Ernie Lewis studies clouds to understand climate

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In October, a trip to Hawaii aboard the Spirit should add data to the ongoing study

Ernie Lewis likes to play the cloud game, looking for familiar shapes in our puffy white neighbors overhead. While he’s contemplating whether that one resembles a dog and this one looks like a lizard, he wonders how he might capture the clouds mathematically or model them in a climate system.

A researcher at Brookhaven National Laboratory, Lewis can appreciate the aesthetic wonder of the clouds even as he would like to understand them much better than modern science currently does. Clouds are one of the most confounding variables in predicting and understanding climate.

“The ability to accurately represent clouds and cloud properties in climate models is lacking and is one of the largest gaps in our understanding,” explained Lewis.

The BNL researcher is at the beginning of coordinating an effort to understand how clouds transition from the predominantly stratocumulus versions in Los Angeles to the mostly cumulus types in Hawaii. A stratocumulus cloud is white, grey or a mixture of the two and often looks thick and dark and appears in waves or sheets. Cumulus clouds, by contrast, look harmless and often have more defined boundaries and look like puffy balls of cotton.

Starting in October, a team of scientists under his direction will travel the 2,548 miles back and forth from California to Hawaii aboard the Horizon cargo ship Spirit. They will bring with them their own container of sophisticated equipment and will launch weather balloons four times a day. The balloons, which contain equipment housed in a small container Lewis said looks like a Chinese food take-out package, will send back information about the temperature, pressure and relative humidity, as well as wind speed and direction.

The scientists will use the information to figure out how clouds change along the route through the Pacific.

Scientists aboard the Spirit will coordinate their data with NASA, which is collecting information from its satellites. The team aboard the cargo ship will compare their photos of the clouds from below with what NASA satellites see from above. This will help validate NASA’s satellite retrieval.

Clouds absorb outgoing infrared radiation from the Earth’s surface, which warms the planet. At the same time, clouds scatter incoming infrared, visible and ultraviolet radiation from the sun, which cools it.

“As nearly all of Earth’s energy comes from the sun, understanding the behavior of this incoming radiation and how it is transferred is important to understanding climate,” Lewis wrote in an online update of his research. You can follow his efforts through the link:

Lewis plans to take the two-week trek aboard the Spirit in October. He will also go back and forth in December or January. Others from the project will ride in September to set up the equipment.

On a test voyage, Lewis said the accommodations are quite comfortable, and include such amenities as a weight room and a lounge with movies.

“We are grateful for Horizon Lines and to the captains and crew of the Horizon Spirit,” Lewis offered.

Lewis, who did oceanographic research through Woods Hole in Massachusetts, is especially appreciative of the size and sturdiness of the ship. When he was aboard smaller vessels in the North Atlantic, he’d get seasick, especially during Nor’easters.
Lewis put his oceanographic background to good use when he wrote a book called “Sea Salt Aerosol Production.” Steve Schwartz and Lewis described how the bubbles comprising whitecaps send seawater drops into the air. The drops evaporate and climb into the atmosphere, where some form the seeds of cloud drops.

“It’s a summary of knowledge of how these are produced,” he explained. “It’s a consolidation of the work that has been done” on these white caps.

Lewis, who lives in Calverton, looks to the skies for one of his other passions, birds. An avid birder, Lewis enjoys going to Fire Island in the fall to watch migrating raptors (i.e., predatory birds, like hawks). He also enjoys watching birds at the lab.

Lewis is married to Northeastern University Professor Laura Henderson Lewis. They commute back and forth from Boston to Long Island.

“I hope my research will lead to a better understanding of clouds and their effect on climate,” he explained.