Constraining the instantaneous aerosol influence on cloud albedo
- Univ. Leipzig, Leipzig (Germany); Imperial College London, London (United Kingdom)
- Univ. Leipzig, Leipzig (Germany)
- ETH Zurich, Zurich (Switzerland)
- National Center for Atmospheric Research, Boulder, CO (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Stockholm Univ., Stockholm (Sweden); Univ. of Exeter, Exeter (United Kingdom)
- Univ. of Oxford, Oxford (United Kingdom)
- Kyushu Univ., Fukuoka (Japan)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nanjing Univ., Nanjing (China); Collaborative Innovation Center of Climate Change, Nanjing (China)
Much of the uncertainty in estimates of the anthropogenic forcing of climate change comes from uncertainties in the instantaneous effect of aerosols on cloud albedo, known as the Twomey effect or the radiative forcing from aerosol–cloud interactions (RFaci), a component of the total or effective radiative forcing. Because aerosols serving as cloud condensation nuclei can have a strong influence on the cloud droplet number concentration (Nd), previous studies have used the sensitivity of the Nd to aerosol properties as a constraint on the strength of the RFaci. However, recent studies have suggested that relationships between aerosol and cloud properties in the present-day climate may not be suitable for determining the sensitivity of the Nd to anthropogenic aerosol perturbations. Using an ensemble of global aerosol–climate models, this study demonstrates how joint histograms between Nd and aerosol properties can account for many of the issues raised by previous studies. It shows that if the anthropogenic contribution to the aerosol is known, the RFaci can be diagnosed to within 20% of its actual value. Furthermore, the accuracy of different aerosol proxies for diagnosing the RFaci is investigated, confirming that using the aerosol optical depth significantly underestimates the strength of the aerosol–cloud interactions in satellite data.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1361962
- Report Number(s):
- PNNL-SA-126491; KP1703040
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 114, Issue 19; ISSN 0027-8424
- Publisher:
- National Academy of Sciences, Washington, DC (United States)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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