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ZJU scholars publish latest research findings about optical absorption of black carbon aerosols

2022-03-15

Recently, Prof. LI Weijun and doctoral student WANG Yuanyuan from the School of Earth Sciences and Prof. HUANG Jin from the College of Computer Science and Technology co-published their research findings about the optical absorption of black carbon (BC) aerosols in Journal of Geophysical Research: Atmospheres and Geophysical Research Letters.

BC, emitted by the incomplete combustion of biomass and fossil fuels, can strongly absorb sunlight in the atmosphere, affecting the regional and global climate through direct and indirect radiative forcing. However, it remains challenging to simulate its optical properties precisely. BC is featured by its complex fractal morphology and constantly changing mixing structures in the atmospheric aging process. As a consequence, the optical absorption of BC is still a controversial subject. At present, there are substantial distinctions between different studies in filed, laboratory, and modelling studies.

In the early 21st century, researchers cast doubt on the absorption of BC and its uncertain impact on global warming. Prof. Li has been dedicated to addressing this controversy in the past eight years. With numerous studies, LI Weijun et al. concluded that the optimal route was to obtain the images of the complex morphology and mixing structures of single BC particles via transmission electron microscopy observations, and then transform them into 3D optical models. Driven by this idea, Prof. Li, Prof. Huang, and doctoral student WANG Yuanyuan co-developed the world’s first Electron-Microscope-to-BC-Simulation (EMBS) tool to construct realistic BC shape models with various morphology and mixing structures for optical calculations using a Discrete Dipole Approximation.

This technological breakthrough acts as a new bridge between the microscopic morphology of realistic BC and optical simulation calculations, thus developing a new tool to reduce the uncertainties in terms of optical simulation and assessment of climate effects. Meanwhile, the researchers developed a novel framework to predict the optical absorption of the atmospheric BC particle population. The study elaborated the evolution of the BC optical absorption in different environments. Therefore, the study is of considerable significance to BC optical simulation and assessment of climate effects.