In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 22, No. 1 ( 2022-01-17), p. 641-674
Abstract:
Abstract. Aerosol–cloud interactions (ACIs) are considered to be the most uncertain
driver of present-day radiative forcing due to human activities. The
nonlinearity of cloud-state changes to aerosol perturbations make it
challenging to attribute causality in observed relationships of aerosol
radiative forcing. Using correlations to infer causality can be challenging
when meteorological variability also drives both aerosol and cloud changes
independently. Natural and anthropogenic aerosol perturbations from well-defined sources provide “opportunistic experiments” (also known as natural experiments) to investigate ACI in cases where causality may be more confidently inferred. These perturbations cover a wide range of locations and spatiotemporal scales, including point sources such as volcanic eruptions or industrial sources, plumes from biomass burning or forest fires, and tracks from individual ships or shipping corridors. We review the different experimental conditions and conduct a synthesis of the available satellite datasets and field campaigns to place these opportunistic experiments on a common footing, facilitating new insights and a clearer understanding of key uncertainties in aerosol radiative forcing. Cloud albedo perturbations are strongly sensitive to background meteorological conditions. Strong liquid water path increases due to aerosol perturbations are largely ruled out by averaging across experiments. Opportunistic experiments have significantly improved process-level understanding of ACI, but it remains unclear how reliably the relationships found can be scaled to the global level, thus demonstrating a need for deeper investigation in order to improve assessments of aerosol radiative forcing and climate change.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-22-641-2022
DOI:
10.5194/acp-22-641-2022-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2022
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
