Alexandra Bozec Eric P Chassignet Overarching goals To produce a validated benchmark highresolution coupled oceaniceatmosphere with HYCOM as the ocean model gt to be compared with GPU code ID: 792980
Download The PPT/PDF document "Coupled HYCOM in CESM and ESPC" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Coupled HYCOM in CESM and ESPC
Alexandra Bozec, Eric P. Chassignet
Slide2Overarching goalsTo produce a
validated benchmark high-resolution coupled ocean-ice-atmosphere with HYCOM as the ocean model => to be compared with GPU code
To evaluate the HYCOM-CESM and HYCOM-ESPC high-resolution configurations; comparison to POP-CESM
Slide3AccomplishmentsConnection of the CESM ice and atmospheric forcing for OCN-ICE and OCN-ICE-ATM configurations
Update of the HYCOM source code from 2.2.35 to 2.2.98Connection of the CESM river transport model (RTM)
Installation of the HYCOM-CESM source code and ESMF 7.0.0beta on the NAVY machines (IBM DataPlex
(Kilrain) and Cray X30 (Shepard))Ran HYCOM-CESM OCN-ICE (50 years) and OCN-ICE-ATM (50 years) for comparison to POP-CESM (50 years)
Evaluation of HYCOM in CESM in OCN-ICE experiments (comparison to stand-alone and POP
) =>
d
iscrepancy
in the ice thickness in Arctic regions
Implementation of the global 0.72º
tripolar
HYCOM grid in CESM for OCN-ICE and OCN-ICE-ATM experiments
Slide4Evaluation of OCN-ICE Comparison of 3 simulations of 20 years:
HYCOM-CESM: HYCOM ocean model coupled with CICE in CESM framework POP-CESM: POP ocean model coupled with CICE in
CESM frameworkHYCOM-CICE: HYCOM coupled with CICE as a stand-alone (NOT in the CESM framework,
but should give results close to HYCOM-CESM)Experimental set-up:
Bipolar POP 1º global grid
Bathymetry from 2-minute NGDC (full steps)
Initialization from rest with
Levitus
PHC2.1
Large and Yeager (
2004) bulk formulation CORE-I atmospheric forcing
Slide5T and S Surface bias
similar bias in T
for HYCOM-CICE, HYCOM-CESM, and POP-CESM
Larger bias in S for POP-CESM in the Arctic, slightly saltier in interior in the HYCOM runs
HYCOM-CICE
HYCOM-CESM
POP-CESM
Slide6Ice cover winter
Similar ice cover in the Arctic for all experiments
Weaker ice cover for the HYCOM experiments, but better in HYCOM-CESM in the Weddell Sea when compared with HYCOM-CICE
HYCOM-CESM
Slide7Ice thickness winter (m)
Arctic: Overestimation of ice thickness in HYCOM-CESM, HYCOM-CICE comparable with POP-CESM
Antarctic: Under for HYCOM-CICE. OK fro HYCOMCESM, over for POP-CESM
HYCOM-CESM
Slide8Ice cover summer
HYCOM-CICE
HYCOM-CESM
POP-CESM
Similar ice cover in the Arctic
Weaker ice cover in HYCOM-CICE in the Antarctic
Slide9Ice thickness summer (m)
O
verestimation of ice thickness in HYCOM-CESM in Arctic
Weaker ice thickness in HYCOM-CICE in the Antarctic
HYCOM-CESM
POP-CESM
HYCOM-CICE
Slide10Possible reasons for the discrepancy in ice thickness
Exchanged fields slightly different between the stand-alone and CESM
Interpolation of the forcing fields through coupler in CESM
is different than in the stand-alone
CICE in CESM is slightly different from CICE in stand-alone and needs to be check out
carefully
to see if we can bring the two versions to run identically.
Coupling frequency:
In CESM framework:
CICE
coupled with HYCOM and ATM
every
3
hours
HYCOM coupled with CICE and ATM every 6 hours
In stand-alone:
CICE
coupled with HYCOM and
ATM
every
6 hours
HYCOM coupled with CICE and ATM every 6 hours
(N.B.: CICE coupled every 6 hours in CESM framework does not work, have to try every 3 hours in stand-alone )
Slide11Exchange FieldsImport Fields:
Wind stress
Net shortwave radiation (ocean+ice
) Downward longwave
radiation
Upward
longwave
radiation
Latent heat flux
Sensible heat flux
Precipitation (rain+snow)
Rivers (
ocean+ice
)
Ice
freezing
/melting heat flux
Ice freshwater flux
Ice salt flux
Ice fraction
Surface ocean current
Sea surface temperature
Sea surface salinity
Ice freeze/melt heat flux potential
Export Fields:
I
ce stress computed in CICE
SSH gradient to compute ocean tilt
CESM
:
Stand-alone:
I
ce stress computer from ice velocity
CESM
:
Ocean current to compute
ocean
tilt
Stand-alone:
Slide12Interpolation of the forcing fields
CESM
Radiative
flux (ocean+ice
)
(W/m2)
Stand-alone
Radiative
flux (
ocean only
)(W/m2)
Slide13Tripolar grid and bathymetry in CESM
g
x1v6 1º bipolar POP grid
g
lbt0.72 0.72º
tripolar
HYCOM grid
Slide14Results with glbt0.72 grid/bathy
2 experiments of 20 years with CORE-I:
HYCOM-CESM with bipolar POP gridHYCOM-CESM-g72 with
tripolar HYCOM grid
HYCOM-CESM2
HYCOM-CESM-g72
HYCOM-CESM-g72
HYCOM-CESM
Similar ice cover and extent between HYCOM-CESM2 and HYCOM-CESM-g72
Similar ice thickness (i.e. same bias)
Slide15On-going and Future WorkUnderstand the reason behind this overestimation of the ice-thickness in the Arctic:
Run stand-alone with ocean ice-stress
Run a HYCOM-CICE stand-alone with atmospheric fields interpolated the same way as in CESM and keep forcing constant between coupling cyclesCarefully check the two versions of CICE and see if we can run them identically
Run a stand-alone HYCOM-CICE with a 3 hours coupling frequencyEvaluate HYCOM-CESM with active atmosphere (OCN-ICE-ATM):
Bipolar POP grid 1º with 1.9º CAM atmospheric model (50 years done, not validated)
Tripolar
HYCOM grid 0.72º with 1.9º CAM atmospheric model (15 years done) => to be compared
to
HYCOM-ESPC
HYCOM-CESM in high resolution:
Tripolar POP grid 1/10º with 0.5º CAM atmospheric model (configuration to be provided to B. Kirtman)
Tripolar
HYCOM grid 0.08º with 0.5º CAM atmospheric model (A. Bozec)
Possibly
Tripolar
HYCOM grid 0.25º with 0.5º CAM atmospheric model to evaluate impact of resolution
For comparison with identical experiments with NAVGEM atmospheric model (HYCOM-ESPC)