Tests of Large-Eddy Simulations of the Stratocumulus Topped Planetary Boundary Layer

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

This grant supports DYCOMS-II (Dynamics and Chemistry of Marine Stratocumulus), a collaborative field program conducted off the coast of California in July 2001. The work consists of (1) an observational study of marine stratocumulus clouds based on seven nocturnal flights of the NCAR C-130 equipped for measuring fluxes in and across the boundary layer; (2) analysis of these and previous data on the cloud-topped marine boundary layer; (3) comparison of the observations with the results of large-eddy simulations (LES). The experiments are designed specifically to provide the data needed to validate LES. Quantities of special interest are entrainment rates, structural features of cloud interfacial properties, and statistical properties of the turbulent air motions. Demonstrating the ability to simulate these quantities is a crucial step in establishing LES as a tool for generating synthetic data to enable the testing of hypotheses and the construction of parameterizations to be used in large-scale atmospheric models.