Aerosol shortwave absorption affects precipitation and other atmospheric phenomena, through local heating, altering lapse rates and affecting cloud formation. Presently, however, absorption from BC, brown carbon (absorbing OC) and dust is very diversely quantified among AeroCom models. There is also no strong observational constraint on the total, global (or regional) aerosol absorption (see paper linked below). Further, BC - the most strongly absorbing anthropogenic aerosol species - has been shown to cause significant spread in predicted precipitation change under global warming between recent Earth System Models. In response, this AeroCom Phase III experiment aims to better quantify the sources of intermodel spread in (total and per-species) short wave aerosol absorption. We request only standard fields (abs550aer, od550aer etc.), but at three wavelengths (550nm, 440nm, 870nm), to allow for more rigorous comparisons to observations. We also request per-species monthly absorption, at the three wavelengths, for BC, BrC and dust separately. Building on this analysis, we aim to provide an updated, hopefully stronger constraint on global mean aerosol absorption.
Timeline: Initial analysis completed by AeroCom 2019. Paper to be submitted by December 2019 (IPCC deadline).
Column with diagnostic requests in excel sheet: ABS
Document(s) with more info: Aerosol Absorption: Progress Towards Global and Regional Constraints (Samset et al. 2018)