Global organic and inorganic aerosol hygroscopicity and its effect on radiative forcing.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37783680.
- Also identified by DOI 10.1038/s41467-023-41695-8 and PMC identifier 10545666.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering diverse environments from pristine to highly polluted conditions. We show that the effective aerosol hygroscopicity, κ, can be derived accurately from the fine aerosol mass fractions of organic particulate matter (ϵ<sub>org</sub>) and inorganic ions (ϵ<sub>inorg</sub>) through a linear combination, κ = ϵ<sub>org</sub> ⋅ κ<sub>org</sub> + ϵ<sub>inorg</sub> ⋅ κ<sub>inorg</sub>. In spite of the chemical complexity of organic matter, its hygroscopicity is well captured and represented by a global average value of κ<sub>org</sub> = 0.12 ± 0.02 with κ<sub>inorg</sub> = 0.63 ± 0.01 as the corresponding value for inorganic ions. By showing that the sensitivity of global climate forcing to changes in κ<sub>org</sub> and κ<sub>inorg</sub> is small, we constrain a critically important aspect of global climate modelling.