Choosing a Convection Scheme for ACME: Recent Progress
Shaocheng Xie1, Phil Rasch2, Wuyin Lin3, J. Yoon2, P. Ma2
1Lawrence Livermore National Lab, 2Pacific Northwest National Lab 3Brookhaven National Lab,
ACME Convection Team S. Xie*, W. Lin, J. Bacmeister, S. Mahajan, R. Neale, Q. Tang, H. Wang, J. Yoon, K. Zhang, Y. Zhang
Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-PRES-667184
ACME & DOE Collaborators S. Ghan, P. Caldwell (SciDAC) S. Klein (RRM) P. Ma (Vert. Res) Y. Qian (Short Simulations) H. Ma (CAPT)
Developer Collaborators V. Larson (CLUBB) A. Gettelman (CLUBB, MG2) P. Bogenschutz (CLUBB) S. Park (UNICON) G. Zhang (ZM-TRIMEM)
Why Is This Effort Needed? The atmospheric component of ACME starts with CAM5.3, but
we will run with SE Dyn-Core with new parameterizations of aerosols and clouds that were developed through the earlier DOE "polar" project.
ACME is a high-resolution Earth System Model with a resolution of 0.250/60-levels for atmos and 1/100 for ocean)
Candidate convection schemes (e.g. CLUBB, UNICON, and ZM variants) have not been extensively tested at such high resolutions
Sensitivity to dynamical core and sub-grid scale orography has not be extensively explored
Adjust to accommodate the other parameterizations
ne30L30 –> ne120L60+
Protocol for Convection Tests
SCM - Single-Column Model CAPT - Cloud-Associated Parameterization Testbed RRM - Regional Refined Model AMIP - Free run with specified SST and Sea Ice Short ensemble UQ - Optimize a set of parameters
A Quick Update • The SCM/CAPT/RRM/UQ capabilities have been added to
ACME • Implementation of candidate schemes started the
beginning of 2015 and most tests were done in the past few weeks
• Implementations to ACME are successfully. One-degree AMIP runs with FV has produced comparable results as shown in the CESM tests for CLUBB and UNICON.
• Issues are found with dynamical cores, model resolutions, and parameter settings
• Tuning and adjustment are necessary to make these schemes work for ACME
Highlights from Initial Tests with one degree AMIP simulations
Mean Precip Improved by CLUBB AMIP 2008-2009, JJA Total Precipitation
CNTL - GPCP
UNICON - CNTL
MG2 - CNTL CLUBB - CNTL
ZMTM - CNTL
Improved Skill in Capturing Diurnal Variability with CLUBB and UNICON
April-July 2009 AMIP: Precip Diurnal Cycle
ZMTM
NEXRAD
CLUBB MG2
CNTL
UNICON
Slide from Wuyin Lin
CLUBB UNICON
Improved MJO with CLUBB and UNICON, but a lack of Kelvin wave in CLUBB OBS CNTL
Issues with Dyn-Cores, Vertical Resolutions, and Parameters
Difference is large between SE and FV with the use of UNICON in ACME
Mean Cloud at the first month
SE - FV
FV
SE
Slide from Jinho Yoon
CESM1 shows similar difference between SE and FV with UNICON – Not an implementation problem!
ACME_UNICON
SE - FV
FV
SE
CESM1_UNICON
Slide from Jinho Yoon
Differences significantly reduced when the orographic forcing term in UNICON turned off
Mean Cloud at the first month
SE - FV
FV
SE
Is there any difference in treating extra tracers in SE vs. in FV?
Slide from Jinho Yoon
CLUBB shows larger sensitivity to vertical resolutions compared to the default schemes
Annual Mean Precip from 1-year AMIP run
Slide from Po-Lun Ma
NE30L30
L64b-L30
L64a-L30
ACME ACME-CLUBB 3.0 mm/day
0.09 mm/day -0.34 mm/day
-0.35 mm/day
2.47 mm/day
0.01 mm/day
Parameter setting matters Precipitation significantly reduced with ACME v0.1 tuning parameters
With NCAR default settings xcldfrc_rhminl = 0.8975 cldfrc_dp1= 0.1 dcs=195D-6 dust_emis_fact= 0.55 zmconv_c0_lnd = 0.0059 zmconv_c0_ocn = 0.045
2.89 mm/day
2.47 mm/day With ACME V0.1 Tuning xcldfrc_rhminl = 0.91 cldfrc_dp1= 0.025 dcs=600D-6 dust_emis_fact= 1.05 zmconv_c0_lnd = 0.0035 zmconv_c0_ocn = 0.0035
Near Team Plan • Have the initial tests with computational inexpensive
modeling testbeds (SCM, CAPT, RRM, AMIP) done in the mid of July, 2015
• Some tunings and adjustments will be done based on the modeling testbeds and vertical resolution will be determined before long-term 0.25 degree resolution simulations can be conducted
• A one-year AMIP/CAPT-type runs with NE120L60+ will be done by the end of August, 2015
• Short ensemble runs might be used to optimize the parameter settings.
Summary • Candidate convection schemes (CLUBB+MG2, UNICON,
ZM variants) have been successfully implemented into ACME and yield similar results as those tested in CESM1
• Issues have been found with the use of SE dyn-core, vertical resolutions, ACME parameter settings
• Tunings and adjustments are inevitably needed to make selected convection scheme work for ACME
• More rigorous tests (including high resolution tests) will be conducted to further assess these schemes before a recommendation could be made
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