Aerosol and non-aerosol drivers of regional trends in top-of-atmosphere albedo over 2002–2020

Clement, N., Bellouin, N. ORCID: https://orcid.org/0000-0003-2109-9559, Boucher, O., Quaas, J., Jia, H. and Tegen, I. (2026) Aerosol and non-aerosol drivers of regional trends in top-of-atmosphere albedo over 2002–2020. Environmental Research Letters, 21 (10). 104012. ISSN 1748-9326 doi: 10.1088/1748-9326/ae687e

Abstract/Summary

Climate change responds to, and in turn modifies, trends in the Earth’s top-of-atmosphere albedo. These trends are caused in particular by anthropogenic aerosol-radiation and aerosol-cloud interactions, as well as by non-aerosol feedbacks involving cloudiness and surface albedo. Here, periods of higher albedo and higher aerosol optical depth (AOD), and periods of lower albedo and lower AOD, are identified in CERES and MODIS satellite retrievals from 2002–2020 over Europe, Eastern North America, Northeastern Asia, and India. Albedo and AOD decrease over 2002–2020 in all regions except India, where both increase. A Gradient Boosting regression is then applied to monthly retrieval differences between these periods to decompose regional albedo trends into aerosol, cloud, and other contributions. Changes in cloud fraction are a primary contributor to albedo trends in Europe, Northeastern Asia, and India. At least half of this contribution is suggestive of aerosol trends. In contrast, in Eastern North America, aerosol-related variations in cloud droplet number and AOD account for most of the observed trend, with a minimal contribution from cloud fraction changes. In Northeastern Asia, changes in surface albedo also contribute strongly to the albedo trend because of variations in snow cover. Sensitivities of top-of-atmosphere albedo to AOD, cloud fraction, liquid water path, droplet number, surface albedo, and surface temperature are calculated regionally and seasonally. These sensitivities can be used to test the magnitude and causes of albedo trends simulated by climate models.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/130612
Identification Number/DOI	10.1088/1748-9326/ae687e
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Institute of Physics
Download/View statistics	View download statistics for this item