Organized, Shallow (Green) Cumulus Over the World's Continents

Abstract:

A major part of continental shallow Cumulus (Cu) fields, forming throughout the world from the tropics to mid- and high-latitudes, seem to share similar properties. One of them being their preferred formation over and near vegetated areas, thus we refer to these clouds hereafter as Green Cu. Green Cu fields show distinct narrow cloud size distribution and high level of linear organization. This work focuses on exploration of this class of clouds. Using a combination of fine- and coarse-resolution satellite observations we classified the observed continental clouds fields into four specific classes, one of them being “green Cu”. We explored green Cu’s properties such as sizes, coverage, and organization. Then, using the identified cloud properties, we developed an identification method for green Cu fields, and used it to detect these fields globally over a period of 10 years. We explore their frequency of occurrence, global spread, seasonality and their link to the surface properties.