An international research team led by Professor Shaocai Yu from the College of Environmental and Resource Sciences, ZJU and Professor Daniel Rosenfeld from The Hebrew University of Jerusalem jointly published a latest research findings titled “Aerosol-driven droplet concentrations dominate coverage and water of oceanic low-level clouds” in Science on January 28, 2019.

Human-made emissions of particulate air pollution can offset part of the warming induced by emissions of greenhouse gases, by enhancing low-level clouds that reflect more solar radiation back to space. The aerosol particles have this effect because cloud droplets must condense on preexisting tiny particles in the same way as dew forms on cold objects; more aerosol particles from human-made emissions lead to larger numbers of smaller cloud droplets. One major pathway for low-level cloud enhancement is through the suppression of rain by reducing cloud droplet sizes. This leaves more water in the cloud for a longer time, thus increasing the cloud cover and water content and thereby reflecting more solar heat to space. This effect is strongest over the oceans, where moisture for sustaining low-level clouds over vast areas is abundant. Predicting global warming requires a quantitative understanding of how cloud cover and water content are affected by human-made aerosols.

  Link:https://science.sciencemag.org/content/363/6427/eaav0566