Parameterization of particle formation rates in distinct atmospheric environments

Abstract. Atmospheric particle formation rate (J) is one of the key characteristics in new particle formation (NPF) processes worldwide. It is related to the development of ultrafine particle growth to cloud condensation nuclei (CCN) and, hence, to Earth radiative forcing in global models, which helps us to better understand the impact of NPF on cloud properties and climate change. In this work, we parameterized four semi-empirical J models for 5 nm atmospheric particles using field measurements obtained from distinct environments that varied from clean to heavily polluted regions and from tropical to polar regions. The models rely primarily on sulfuric acid as a condensing vapor, condensation sink to account for the vapor loss, and relative humidity for meteorological contribution to J. The parameterization results showed that our models were able to produce plausible predictions for boreal forest environments, heavily polluted environments, and biogenic environments with high relative humidity. We further tested the models in the global simulation module Tracer Model 5 (TM5, massive parallel version) to simulate particle number size distribution across 14 global atmospheric measurement sites. The simulated results showed satisfactory predictions on particle number concentrations for all the tested environments, with significant improvement in the nucleation mode, and better prediction accuracy for Aitken and accumulation modes compared to the binary sulfuric acid-organic vapor model in Riccobono (2014). Our study has successfully provided powerful tools to predict J₅ on a global scale across various environment types using the most essential and more accessible variables involved in the NPF processes. Essentially, this work reinforces the necessity for global research into the investigation of environment-oriented meteorology-involved NPF processes.