EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Measuring cloud sensitivity to aerosols at a global scale using isolated aerosol sources

Edward Gryspeerdt1,2, Manuel Louro Coelho1, Tristan Smith3, Santiago Suarez De La Fuente3, Rodrigo Quilelli Correa Rocha Ribeiro4, and Maarten van Reeuwijk4
Edward Gryspeerdt et al.
  • 1Space and Atmospheric Physics Group, Imperial College London, London, UK (
  • 2Grantham Institute - Climate Change and the Environment, Imperial College London, London, UK
  • 3UCL Energy Institute, University College London, London, UK
  • 4Department of Civil and Environmental Engineering, Imperial College London, London, UK

The sensitivity of clouds to anthropogenic aerosol perturbations remains one of the largest uncertainties in the human forcing of the climate system. A key difficulty is in isolating the impact of aerosols from large-scale covariability of aerosol and cloud properties. Natural experiments, where aerosol is produced independently of the cloud and meteorological properties, provide a pathway to address this issue. These aerosol sources often modify cloud properties, leaving linear cloud features known as shiptracks (when formed by a ship) or pollution tracks (more generally).

In this work, we use a database of point sources of aerosol over both land and ocean to identify clouds that are sensitive to aerosol and to measure their response. Using a neural network to identify when a point source is modifying the cloud, we are able to measure the sensitivity of individual clouds to aerosol at a global scale, looking at over 400 million cases.

We find the probability of track formation is strongly dependent on the background cloud and meteorological state, similar to previous regional studies. With our global database, we identify regions that are strongly susceptible to aerosol perturbations, even where aerosol sources are rare. We find that there are several regions that are highly susceptible to aerosol, but that have been previously overlooked due to a low frequency of pollution tracks.    

How to cite: Gryspeerdt, E., Louro Coelho, M., Smith, T., Suarez De La Fuente, S., Quilelli Correa Rocha Ribeiro, R., and van Reeuwijk, M.: Measuring cloud sensitivity to aerosols at a global scale using isolated aerosol sources, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9756,, 2022.