BEACHON Shines a Light on Plant-Atmosphere Interactions
Mountain pine beetles are eating their way through huge swaths of forest in western North America. These pests are doing more than ruining the natural scenery—they’re also altering local weather patterns.
In the Rocky Mountains, NCAR scientists are exploring how trees and other vegetation influence clouds, rainfall, and temperatures as one part of an international field project, BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics, and Nitrogen).
By studying interactions between the planet’s surface and the atmosphere, BEACHON (pronounced “beacon”) will allow scientists to glean insights into local air quality and long-term climate change, as well as weather patterns. By studying interactions between the planet’s surface and the atmosphere, BEACHON (pronounced “beacon”) will allow scientists to glean insights into local air quality and long-term climate change, as well as weather patterns. Plants emit water vapor and other gases, in addition to microscopic particles that influence the atmosphere in subtle and complex ways. When portions of a forest die, the local atmosphere can change.
“In terms of impacts on the atmosphere, there’s a big difference between a living forest and a dead forest,” says Alex Guenther, a scientist in NCAR’s Atmospheric Chemistry Division who’s a principal investigator on the project. “With a dead forest, we may get different rainfall patterns, for example.”
When large areas of trees are killed by pine beetles or other causes, interactions between Earth’s surface and the atmosphere are disrupted. Scientists believe that this can change cloud and precipitation patterns at least for the short term, which can, in turn, further alter the land cover. Temperatures could rise because there are fewer particles in the air to block incoming sunshine, fall because there are fewer gases to trap solar radiation and prevent it from escaping into space, or change in more subtle ways because of new cloud cover patterns. Forest changes also influence local temperatures, in part because plants, soil, and other types of land cover absorb varying amounts of incoming heat from the Sun.
BEACHON researchers will use specially equipped aircraft as well as towers that reach above the forest canopy to measure emissions at up to about 100 feet above the ground. Additional observations will come from a variety of soil and moisture sensors, sensors for gases and tiny particles, plus radars and lidars (laser-based radar).
“BEACHON will give us a very comprehensive picture of a forest’s impact on the atmosphere,” Guenther says. “But at this point, we don’t know what the project will reveal. We may end up with more questions than answers.”
