Characteristics of 3D Cloud Properties During the LASIC Campaign

Description

Many climate model simulations have shown the so-called “too few, too bright” problem in the tropical marine environment. The “too few” problem, an underestimate in cloud amount, allows more solar radiation to reach the surface. The “too bright” problem, an overestimate in cloud albedo due, for example, to an overestimate in the amount of liquid water within the cloud, causes more sunlight to be reflected. Combined, these biases in absorbed solar radiation are of opposite signs, leading to an apparently realistic radiation budget despite inaccurate cloud properties. However, resolving this issue is important for cloud feedback studies because overly reflective clouds in models may have led to a significant underestimate in the strength of a negative cloud feedback process involving increased cloud liquid water with warming. The scanning capability of ARM cloud radars provides an excellent opportunity to observe cloud life cycles, which will greatly help to investigate the processes responsible for the too few, too bright problem. Capitalizing on measurements from ARM scanning radars/lidars and shortwave spectrometers, we report cloud properties observed during the Layered Atlantic Smoke Interactions with Clouds (LASIC) campaign, with an emphasis on shallow cumulus clouds. Cloud clustering and size distributions are shown, and will be used in parameterization development for a recently developed fast scheme that incorporates 3D radiative transfer effects.