Department of Chemistry - PhD Student Seminar - Ice-Core Chemical Archives as Model Constraints: From Mature Fire Proxies to Organic Aerosol Frontiers

Student: Ms. Shumin LIANG

Department: Department of Chemistry, HKUST

Supervisor(s): Prof. Jianzhen YU

Abstract

Ice cores preserve a unique record of past atmospheric composition by trapping ancient gases and aerosols. As chemical archives, they provide independent, long-term constraints for Earth system models by, for example, establishing pre-industrial baselines and benchmarking model simulations. Historically, ice‑core research has focused on inorganic impurities (major ions, trace elements) and gases, while the organic fraction has remained underexplored due to analytical challenges and interpretive difficulties.

This seminar first reviews established ice-core fire proxies, including black carbon, carbon monoxide, and acetylene. These records suggest that pre-industrial biomass burning was substantially stronger than standard emission inventories have assumed, highlighting the need to revise baseline aerosol forcing in climate models. The second half of the seminar highlights emerging organic aerosol constraints, which provide more detailed source-specific and process-level information. Case studies involving biomass burning, biosphere-derived secondary organic aerosols, and sea-ice-related tracers demonstrate how these compounds can complement traditional proxies and refine model interpretation. Overall, expanding the ice-core proxy toolkit to include organic tracers offers a more nuanced and multifaceted basis for evaluating climate-biosphere-aerosol interactions and, ultimately, for improving future climate projections.