Observations focused on continuous, long-term aerosol measurements over forest environments
With every breath we take, we inhale many particles with a diameter much smaller than the width of a human hair. These small particles, sometimes referred to as aerosols, play an important role in the formation of clouds and precipitation. They also contribute to particulate matter air pollution that has been shown to lead to a number of respiratory health problems as well as damage to forest ecosystems. A new instrument for measuring aerosols on a long-term basis, developed by researchers at Colorado State University and funded by the Department of Energy has recently been installed at NOAA’s Air Resources Laboratory (ARL) in Oak Ridge, Tennessee. The information from the sensor could lead to more accurate weather and air quality forecasts.
The flow and number of particles that pass through an area over time between the atmosphere and the Earth’s surface are important variables in many of NOAA’s forecast models. Data that provides an accurate spatial and temporal distribution of particles for these models is vital for accurate forecasts; however, Rick Saylor, Ph.D., an ARL physical scientist, has noted that direct particle measurements over forests are routinely 10-100 times larger than what theoretical models say they should be, especially for particles with sizes less than one micrometer in diameter.
Accurate measurements of particle fluxes over a variety of land surface types are necessary to better understand the reasons for the discrepancies between models and direct measurements and to improve the way these fluxes are represented in weather, climate and air quality computer models.
To meet this need, Delphine Farmer, Ph.D., and her group at Colorado State University used funding provided by the U.S. Department of Energy to create a network of instruments to measure particle fluxes over different landscape types on a continuous, long-term basis. Previous measurements have been limited to short-term intensive field campaigns, so the goal is for the Fluxes of Aerosol Continuous Observing Network (FALCON) to provide the first long-term dataset extending over several seasons at representative sites across the U.S.
ARL’s flux tower in Oak Ridge is now part of FALCON and the team has been working with CSU for the past year on instruments at ARL’s Chestnut Ridge site. Situated in a mixed deciduous forest, the Chestnut Ridge site has a 200 foot tower with instruments that measure energy, carbon dioxide and water vapor fluxes between the atmosphere and the surface. The site is part of ARL’s Surface Energy Budget Network and in addition to being used for ARL research, it routinely hosts instruments from collaborations with other NOAA labs, government agencies and university partners. After discussions with Farmer and her group, collaborations began last summer and a new FALCON instrument was installed on the Chestnut Ridge tower this summer.
“Measurements obtained at FALCON sites will be extremely useful to advance the science of particle fluxes between the surface and our atmosphere, and should help increase the accuracy of weather and air quality forecasts and predictions of future climate change,” Saylor says.
Media Contact: Alison Gillespie, alison.gillespie@noaa.gov, 202-713-6644
