ON THE GLOBAL VARIATION OF PRECIPITATING LAYER CLOUDS

The aim of the Global Energy and Water Cycle Experiment Cloud System S tudy (GCSS) is to promote the description and understanding of key clo ud system processes, with the aim of developing and improving the repr esentation of cloud processes in general circulation models. The GCSS Science Panel identified a need to document important observational ga ps in the structure of cloud systems inhibiting the development of clo ud-resolving models as a tool for parameterizing cloud systems in gene ral circulation models. The nature of precipitating layer clouds aroun d the world is not well documented. To better quantify this, a synthes is of observations of these types of clouds made during field experime nts conducted around the world has been developed. The synthesis draws on observations made in Australia, Canada, China, Israel, Japan, Russ ia, the Ukraine, the United States, and several European countries. Th e survey examines the global variation of the horizontal scales of clo ud and precipitation, embedded phenomena such as rainbands, conveyor b elt characteristics, ice crystal and water droplet concentrations, and raindrop and ice crystal size distributions.