Eddy-Diffusivity/Mass-Flux EDMF

Funded NOAA/NSF Climate Process Team effort

The goal of this project is to reduce key biases related to boundary layer clouds and deep convection in the latest version of the National Center for Atmospheric Research (NCAR) climate model, by implementing, and evaluating, in the NCAR model, a new unified boundary layer and convection parameterization based on the multi-plume Eddy-Diffusivity/Mass-Flux approach (EDMF; Siebesma et al., 2007). This is a turbulence and convection parameterization that can be considered fully unified, since it is able to represent convective processes from boundary layer convection (dry and cloudy) to deep moist convection with one single parameterization. This project will be focused on the boundary layer and the transition to deep convection. In particular, (i) the spatial transition over the oceans from the stratocumulus topped boundary layer to cumulus (shallow convection) boundary layers and to deep convection, and (ii) the temporal transition (diurnal cycle) over land from dry convection, to shallow convection and to deep precipitating convection.

Siebesma, A.P., P.M.M. Soares, and J. Teixeira, 2007: A Combined Eddy-Diffusivity Mass-Flux Approach for the Convective Boundary Layer. J. Atmos. Sci., 64, 1230-1248. Doi: 10.1175/JAS3888.1


Figure: Total water and liquid water potential temperature distributions sampled in the BOMEX cumulus layer at 1000m from LES output (color contours) and the corresponding values from the EDMF parameterized plumes over 60 min of integration (black stars)

Suselj, K., Kurowski, M. J., & Teixeira, J. (2019). A Unified Eddy-Diffusivity/Mass-Flux Approach for Modeling Atmospheric Convection, Journal of the Atmospheric Sciences, 76(8), 2505-2537. Doi: 10.1175/JAS-D-18-0239.1


Figure: Schematic of three archetypes of convection as represented by the EDMF model: (left) dry, (middle) shallow, and (right) deep convection

Project Contacts