Although tiny atmospheric aerosols are some of the most highly studied particles known to effect Earth, scientists are still unsure of how they form and their impacts on climate. Now, researchers from the Pacific Northwest National Laboratory have created new models of the birth and growth of important aerosols that will help us better understand their effects on our planet.
"Most atmospheric climate models either neglect or estimate how new particles are formed and evolve, rather than using real-world data," said Jerome Fast, who led the study. "We used data from observations to create and test three new approaches to model particle formation."
Aerosols are tiny particles that are criticized for their potentially negative effects on climate and their role in the chemical changes in the atmosphere. However, despite knowledge of their ability to scatter the sun's energy and prompt a cooling effect on the Earth's atmosphere, accurately representing their life cycle in a climate model is difficult.
In order to integrate these particles into climate models and understand their impacts on the environment, real-world measurements of their concentration, size and mass are needed. In the current study, the team used the Weather and Research Forecasting model in combination with chemistry (WRF-Chem) in order to use growth data from the 2010 Carbonaceous Aerosol and Radiative Effects Study (CARES) to simulate their formation and growth.
The team created climate models that expanded the size for aerosol simulation to include both ultrafine and larger particles and used surface and airborne measurements of particle number concentration. They also examined differences in condensation, coagulation, transport, deposition and emissions rates among three different approaches: number concentration, size distribution and cloud condensation nuclei.
Due to the difficulty of pinning down aerosol size distribution, future research will continue to study various aerosol particle sources and meteorological conditions in order to further evolve the current models.
"The modeling approaches generally matched our data showing how the concentrations of ultrafine particles changed with time," Fast said. "The results of our study are promising, but we still have more to do in this area to truly understand how aerosols are born."
The findings were published in the Nov. 6 issue of Atmospheric Chemistry and Physics.
