Salter S. 2022 Simulations of a Demonstration of Cloud Albedo Change
Description
The reflectivity of marine stratocumulus clouds can be increased by a change of the concentration of cloud condensation nuclei. The increase can be sufficient to reverse global warming Latham et (2008). This paper shows the results as a function of initial cloud conditions and spray quantity and shows that it may be difficult to detect planet saving effects by eye. 1.Twomey (1977)showed that the reflectivity of a cloud depends on the size distribution of its drops. For the same liquid water content, a large number of small drops will reflect more than a small number of large ones. For a wide range of cloud conditions, doubling the number of drops will increase reflectivity by about 0.056, Schwarz and Slingo (1996). In clean mid-oceanic clouds the concentration of cloud drops (set by humidity and the availability of condensation nuclei) is quite low, often between 50 and 100 per cm3 Bennartz (2007) and sometimes as low as 10. The salty residues left after the evaporation of submicron drops of sea spray are ideal cloud condensation nuclei. Latham (1990) (2008) suggested spraying sub-micron drops of sea water into the marine boundary layer to increase the reflectivity of marine stratocumulus clouds and send more solar energy back out to space.