Toward low-cloud-permitting cloud superparameterization with explicit boundary layer turbulence -- simulation data
Data files
This dataset is embargoed . Please contact Hossein Parishani at ude.icu@hsirap.h with any questions.
Lists of files and downloads will become available to the public when released.
Abstract
This data set contains the simulation outputs used in the study summarized below:
Systematic biases in the representation of boundary layer (BL) clouds are a leading source of
uncertainty in climate projections. A variation on superparameterization (SP) called ‘‘ultraparameterization’’
(UP) is developed, in which the grid spacing of the cloud-resolving models (CRMs) is fine enough
(250x20 m) to explicitly capture the BL turbulence, associated clouds, and entrainment in a global climate
model capable of multiyear simulations. UP is implemented within the Community Atmosphere Model
using 2-degree resolution (14,000 embedded CRMs) with one-moment microphysics. By using a small domain
and mean-state acceleration, UP is computationally feasible today and promising for exascale computers.
Short-duration global UP hindcasts are compared with SP and satellite observations of top-of-atmosphere
radiation and cloud vertical structure. The most encouraging improvement is a deeper BL and more realistic
vertical structure of subtropical stratocumulus (Sc) clouds, due to stronger vertical eddy motions that
promote entrainment. Results from 90 day integrations show climatological errors that are competitive with
SP, with a significant improvement in the diurnal cycle of offshore Sc liquid water. Ongoing concerns with
the current UP implementation include a dim bias for near-coastal Sc that also occurs less prominently in SP
and a bright bias over tropical continental deep convection zones. Nevertheless, UP makes global
eddy-permitting simulation a feasible and interesting alternative to conventionally parameterized GCMs or
SP-GCMs with turbulence parameterizations for studying BL cloud-climate and cloud-aerosol feedback.
Usage notes
All instructions and information are provided in the attached Readme.txt file. Please download the latest version for the full data set.