Boundary layer gradients in new particle formation
25 April 2023 - 25 May 2023
Lead Scientist: Eleanor Browne
New particle formation (NPF) followed by growth is a major source of cloud condensation nuclei (CCN) and thus impacts our understanding how aerosols affect cloud life cycle, properties, and processes. NPF and growth is known to occur throughout the troposphere; however, much of our knowledge of NPF and growth are derived from surface‐based measurements. Although few measurements of the vertical distribution of NPF and growth exist, emerging evidence from the available measurements, including from prior measurements at the Atmospheric Radiation Measurement Southern Great Plains Facility, suggests that NPF and growth occurs heterogeneously throughout the boundary layer. Moreover, the prior work highlights a critical need for additional measurements that probe both the vertical distribution of NPF and growth and the detailed chemical characteristics of the surface layer.
Here, we will deploy state-of-the-art high-resolution mass spectrometers at the Southern Great Plains Guest Instrumentation facility to probe atmospheric chemical composition at the surface and custom condensation particle counters on the tethered balloon system (TBS) to measure vertically resolved aerosol cluster concentration (1-3 nm). These measurements will be complemented by TBS-provided meteorological measurements, routine measurements from the Aerosol Observing System, particularly the nano and the regular scanning mobility particle sizers, and atmospheric remote-sensing measurements. We will use these measurements together to investigate the vertical distribution and frequency of NPF and growth. These critical measurements are needed: (1) because NPF aloft followed by transport and growth of particles to the surface may be a significant contribution to the cloud condensation nuclei budget; however, the extent and frequency of this process is poorly constrained, (2) to connect the atmospheric conditions that drive atmospheric NPF with boundary-layer processes and meteorology, and (3) to evaluate the extent to which surface‐based aerosol measurements are representative of the atmospheric aerosol aloft. Insights gained from the proposed work will ultimately contribute to improving our understanding of aerosol processes that affect clouds.