Confronting a multi-plume scheme with observations of continental
shallow convection
Abstract
Multi-plume convection schemes based on discretized size densities can
be easily made scale-aware by size filtering the parametrized plumes to
fit the model resolution. Combined with their capability to smoothly
transition from shallow to deep convection while being both numerically
robust and computationally viable, these bin macrophysics models are
well suited to the needs of high resolution NWP and regional climate
modeling. One such approach is the ED(MF)n scheme which has previously
been evaluated in a single column model against maritime cumulus LES. In
this presentation we will confront the ED(MF)n scheme with long-term
Doppler lidar observations of shallow cumulus days from the ARM-SGP site
in Oklahoma. To do so the ED(MF)n scheme is implemented and tested in a
non-hydrostatic model on a microgrid of 8x8 or 16x16 gridpoints. By
using a ~10 km resolution this system behaves as a
collection of weakly interacting single column models. We will compare
the modeled relationship of vertical velocity to plume size against the
relationship found in both the Doppler lidar observations and the LASSO
LES run routinely at the ARM-SGP site. Next we examine which effect the
assumed cloud-size distribution and entrainment as a function of plume
size have on the resulting vertical transport.