Scientists Create 'Cloud In A Box' To Solve Atmospheric Mysteries

Atmospheric scientists and engineers at Brookhaven National Laboratory have successfully created what they're calling a "cloud in a box," a programmable atmosphere designed to help researchers unlock fundamental mysteries about how clouds form and behave. The achievement marks a significant breakthrough in atmospheric science, as clouds remain one of the biggest sources of uncertainty in weather and climate models.

Inside a one-cubic-meter metal chamber, researchers recently watched as tiny particles illuminated by green light swirled into a haze and formed a wisp of cloud. "We saw the birth of a cloud," Brookhaven atmospheric scientist Arthur Sedlacek noted in a press release. "There was a lot of excitement and happiness, and relief, in that moment."

The convection cloud chamber works by combining the key ingredients needed for cloud formation: supersaturated air and aerosol particles. Scientists heat water at the chamber's base, creating warm, humid air that rises and mixes with cool air from the cold top panel. When they inject aerosol particles such as table salt into this environment, water vapor condenses on these "seeds," forming cloud droplets. The chamber can maintain a turbulent cloud in steady state for hours, allowing for repeated measurements that would be impossible in nature.

While clouds play crucial roles in regulating Earth's energy balance, water movement through the atmosphere, and storm formation, many basic questions remain unanswered. "One long-standing unsolved problem in our community is how drizzle or raindrops are formed in warm clouds," Sedlacek said in the press release. "Why do some clouds precipitate while others do not?" Traditional field research involves flying specially equipped aircraft through clouds, but each pass captures a cloud that has already changed since the previous measurement.

The new facility, one of only two convection cloud chambers in the United States, offers unprecedented control over experimental conditions. Researchers can adjust heating and cooling panels to manipulate relative humidity, temperature, and turbulence, while advanced imaging techniques using lasers and radar track cloud development without physically disturbing it. In the future, researchers say, this work could expand beyond cloud physics to study how atmospheric conditions affect energy infrastructure and the movement of biological particles like pollen and pathogens.