Airborne campaign targets weather, climate science

MANILA, Philippines — To help improve weather and climate forecasts, the National Aeronautics and Space Administration (NASA)’s P-3B science aircraft soared into the skies over the Philippines on Sunday to begin an extensive two-month investigation on the impact that smoke particles from fires and pollution have on clouds.

The Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) is the most comprehensive field campaign to date in maritime Southeast Asia to study the relationship between aerosol particles as they interact with surrounding monsoon meteorology, cloud microphysics and the sun’s radiation.

Led by NASA, the United States Naval Research Laboratory (NRL) and the Manila Observatory in conjunction with the Philippine Atmospheric, Geophysical and Astronomical Services Administration and the Department of Science and Technology, CAMP2Ex comprises an interdisciplinary, international team of field researchers, modelers and remote sensing developers.

The study seeks to tackle some of the most difficult weather and climate phenomena to understand, monitor and forecast. The maritime continent – comprising Sumatra, the Malay peninsula, Borneo, Sulawesi, the Philippines and numerous other islands and surrounding seas – has been long sought out as an area of scientific inquiry. 

“We know aerosol particles can affect clouds and precipitation, but we don’t yet have a quantitative understanding of those processes,” said Hal Maring, radiation sciences program manager at NASA headquarters in Washington. “Our goal is to improve satellite products and numerical models to help scientists better predict weather and climate.”

“Numerous studies have linked the presence of pollution and smoke from agricultural fires and fires from deforestation to changes in cloud and storm properties, but we lack the observations of the actual mechanisms taking place,” said NRL research meteorologist Jeffrey Reid. “CAMP2Ex provides a much-needed crucible for satellite observing systems and model predictions to monitor and understand how atmospheric composition and weather interact.”   

Reid said aerosol-cloud dynamics have a profound impact on weather and climate but there are large uncertainties in how those dynamics affect climate. Aerosol particles include sea salt, dust, air pollutants and biomass-burning smoke particles, and nearly all can act as cloud condensation nuclei (also known as cloud seeds). 

Depending on the size and composition of these aerosol particles, water vapor can coalesce around them to form water droplets that may later become rain. But if there is a high concentration of aerosol particles, the clouds may be populated with a larger number of smaller drops, which are less likely to coalesce into rain in smaller clouds. 

“Yet recent research shows that these smaller drops may strengthen and increase the longevity of severe storms,” Reid said. “It’s an intricate science.”

Maring said aerosol-cloud interactions are notoriously difficult to observe in the field.

“Some clouds have very short lifetimes while others have very long ones, and they’re all located in radically different parts of the skies. Getting a quantitative look at these processes is always a tall order,” Maring said.