10.7280/D1TH5T
Parishani, Hossein
University of California, Irvine
Pritchard, Michael
University of California, Irvine
Bretherton, Christopher
University of Washington
Wyant, Matthew
University of Washington
Khairoutdinov, Marat
Stony Brook University
Toward low-cloud-permitting cloud superparameterization with explicit
boundary layer turbulence -- simulation data
Dryad
dataset
2019
United States Department of Energy
https://ror.org/01bj3aw27
DE-SC0012548
2020-01-01T08:00:00Z
en
https://doi.org/10.1002/2017MS000968
49064521837 bytes
14
Creative Commons Attribution 4.0 International (CC BY 4.0)
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.
All instructions and information are provided in the attached Readme.txt
file. Please download the latest version for the full data set.