Detection of Aerosol-Cloud Interactions in Shallow Cumulus during LASSO
Authors
Graham Feingold — NOAA- Earth System Research Laboratory
Ian B Glenn — University of California, Los Angeles/Jet Propulsion Lab.
Takanobu Yamaguchi — CIRES, Unviersity of Colorado and NOAA ESRL
Category
Warm low clouds, including aerosol interactions
Description
We present a framework for studying aerosol-cloud interactions during the LES ARM Symbiotic Simulation and Observation(LASSO) project. The detectability of aerosol perturbations on cloudy scene albedo is considered with respect to aerosol variability, meteorological variability, and their co-variability. For alpha-1 (2015) LASSO cases it is shown that although aerosol perturbations on the order of 50 - 100% are detectable in scene albedo (cloudy plus cloud-free), the diurnal cycle of shallow convection has a distinct temporal trace that overwhelms aerosol perturbations of this magnitude. The temporal trace, as manifested in scene albedo vs. cloud fraction diagrams, is related to the evolution in continental convection, and the cloud aspect ratio (depth vs. area). Results suggest that a prerequisite to detecting aerosol effects on albedo is representing the diurnal cycle of the cloud fields with fidelity. Differences in results associated with initial soundings, boundary conditions, and large-scale forcing data sets will be presented. Time permitting, results for LASSO alpha-2 will also be presented.
