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Abstract. New particle formation (NPF) events are defined as asudden burst of aerosols followed by growth and can impact climate bygrowing to larger sizes and under proper conditions, potentially formingcloud condensation nuclei (CCN). Field measurements relating NPF and CCN arecrucial in expanding regional understanding of how aerosols impactclimate. To quantify the possible impact of NPF on CCN formation, it isimportant to not only maintain consistency when classifying NPF events butalso consider the proper timeframe for particle growth to CCN-relevantsizes. Here, we analyze 15 years of direct measurements of both aerosol sizedistributions and CCN concentrations and combine them with novel methods toquantify the impact of NPF on CCN formation at Storm Peak Laboratory (SPL),a remote, mountaintop observatory in Colorado. Using the new automaticmethod to classify NPF, we find that NPF occurs on 50 % of all daysconsidered in the study from 2006 to 2021, demonstrating consistency withprevious work at SPL. NPF significantly enhances CCN during the winter by afactor of 1.36 and during the spring by a factor of 1.54, which, when combined withprevious work at SPL, suggests the enhancement of CCN by NPF occurs on aregional scale. We confirm that events with persistent growth are common inthe spring and winter, while burst events are more common in the summer andfall. A visual validation of the automatic method was performed in thestudy. For the first time, results clearly demonstrate the significantimpact of NPF on CCN in montane North American regions and the potential forwidespread impact of NPF on CCN.
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Formation Process of Particles and Cloud Condensation Nuclei Over the Amazon Rainforest: The Role of Local and Remote New‐Particle Formation
Abstract Understanding the formation processes of particles and cloud condensation nuclei (CCN) in pristine environments is a major challenge in assessing the anthropogenic impacts on climate change. Using a state‐of‐the‐art model that systematically simulates the new‐particle formation (NPF) from condensable vapors and multi‐scale transport of chemical species, we find that NPF contributes ∼90% of the particle number and ∼80% of the CCN at 0.5% supersaturation (CCN0.5%) in the pristine Amazon boundary layer during the wet season. The corresponding contributions are only ∼30% and ∼20% during the dry season because of prevalent biomass burning. In both seasons, ∼50% of the NPF‐induced particles and ∼85% of the NPF‐induced CCN0.5% in the boundary layer originate from the long‐range transport of new particles formed hundreds to thousands of kilometers away. Moreover, about 50%–65% of the NPF‐induced particles and 35%–50% of the NPF‐induced CCN0.5% originate from the downward transport of new particles formed aloft.
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- Award ID(s):
- 2132089
- PAR ID:
- 10380595
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 22
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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