Observations and modeling of turbulence in the developing convective boundary layer
Authors
Mikhail Ovchinnikov — Pacific Northwest National Laboratory
Mikhail S. Pekour — Pacific Northwest National Laboratory
Larry Berg — Pacific Northwest National Laboratory
Category
Boundary layer structure, including land-atmosphere interactions and turbulence
Description
Land-atmosphere-cloud interactions cannot be fully understood, or successfully modeled, without an accurate characterization of boundary-layer turbulence, which is intimately linked to both fluxes from the underlying surface and cloud formation processes. In this study, we compare characteristics of turbulence in developing convective boundary layers at the ARM Southern Great Plains site observed during selected days from the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) field campaign and modeled by the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) project. Observations include measurements of temperature, moisture and vertical velocity from aircraft instrumentation and ground-based Doppler lidars, from which vertical fluxes of sensible and latent heat are derived. The flux profiles are compared with those modeled by LES and, for the morning convective activity, with theoretical predictions. Observed and modeled rates of boundary layer growth, as well as probability density functions and power spectra of vertical velocity are also analyzed. Finally, observational uncertainties related to limited accuracy and sampling of the required measurements and modeling uncertainties due to large scale forcing and limited LES domain and resolution are discussed.
