Precipitation driving of droplet concentration variability in marine low clouds A simple steady-state budget model for cloud condensation nuclei, driven by observed precipitation variability in low clouds from CloudSat (figure below), can predict the MODIS-observed cloud droplet concentration variability over low cloud regions with considerable skill (see figure on right). Results imply significant impacts of light precipitation on aerosol climatology over the global oceans Above: Cloud droplet concentrations in regions of extensive marine low clouds observed by satellite and from the budget model. Annual mean cloud droplet concentration N­d for extensive marine low clouds under conditions of large scale subsidence, from MODIS (top); from the CCN budget model (bottom) for the same regions. Above: Mean precipitation rate at cloud base from low clouds (cloud top height ztop<3 km) estimated with spaceborne radar measurements from CloudSat. Data are screened to display regions of extensive marine low clouds under conditions of mean subsidence as in figure on right. R. Wood, D. Leon, M. Lebsock, J. Snider, A. D. Clarke. Precipitation driving of droplet concentration variability in marine low clouds. J. Geophys. Res., 117, D19210, doi:10.1029/2012JD018305, 2012.