CAREER: Role of New Particle Formation in Pre-industrial Climate

This CAREER project focuses on assessing the role of atmospheric new particle formation in influencing the pre-industrial climate. A new parameterization of new particle formation that accounts for the role of temperature and atmospheric ions will be developed and its effectiveness will be evaluated through climate models. This research will help to improve the understanding of aerosol-cloud interactions and reduce the uncertainties in the role of aerosol in climate evolution. Currently, NPF and aerosol growth is poorly represented in most global climate models. The newly developed parameterizations of new particle formation mechanisms will improve model predictions of cloud condensation nuclei (CCN) and cloud droplet concentrations (Nd). The chemical production of organic material from biogenic volatile organic compounds (BVOCs) that plays a role in NPF will be investigated with and without sulfuric acid, ammonia and atmospheric ions. A land surface model including prognostic fires will be used to determine the role of NPF and BVOCs in buffering aerosol variability due to biomass burning. The combination of empirical data from the CERN CLOUD experiment and extensive field measurements will enhance the accuracy and relevance of the climate modeling. The models will be used to improve constraints on pre-industrial cloud droplet concentrations and aerosol radiative forcing, by considering aerosol sources and sinks in different meteorological regimes and simulated changes from 1850 to 1950. The models also will be tested on the current-day atmosphere under a variety of conditions that enable an assessment of the ability to recreate the preindustrial atmosphere. Working with The Citizen Science Lab, an after-school pipeline program will be developed for high-school students in the region to gain experience in field measurements and scientific data analysis through demonstrations and hands-on activities. For example, students will make and interpret smartphone photographs of clouds using NASA’s Globe Clouds app and will be introduced to environmental history over the industrial period via case studies in the Pittsburgh region. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.