Validation Analysis Validation Analysis of the of the

0.720.72˚̊ HYCOM/CICE 4.0 HYCOM/CICE 4.0 2003-2006 run2003-2006 run

Dmitry Dukhovskoy, Pam Posey, Joe Metzger, Dmitry Dukhovskoy, Pam Posey, Joe Metzger, Alan Wallcraft, and Eric ChassignetAlan Wallcraft, and Eric Chassignet

Participant in the International partnership program funded by NSF:

Arctic Ocean Model Intercomparison Project (AOMIP).

AOMIP Goals:

(1) Validate and improve Arctic Ocean models in coordinated fashion

- identify the most consistent errors across models

- propose solutions

- select the most reliable and consistent Arctic Ocean / Sea Ice models

(2) Investigate processes using observations and model results

- How to avoid restoring and flux correction?

- Formation of the Arctic Ocean halocline

- Parameterization of stress-driven and convection-driven mixing

(3) Climate change

- 50-year experiment under “observed” forcing and 100-year experiment under reconstructed forcing

Arctic Study at COAPS Arctic Study at COAPS FSUFSU

AOMIP ModelsAOMIP Models

Institution AWI GSFC UW NPS UMASS / WHOI

FSU (ARCc0.72 / ARCc0.08)

Ocean Model

MOM POM MOM MOM FVCOM HYCOM

Ice Coupled Yes Yes Yes Yes Yes Yes

Vertical Levels

Z levels sigma 30 Z levels 30 Z levels 40 s-layers 32 hybrid

Resolution >20 km ~22 km ~18 km 1 km shelf

~15 km deep

~30 km /

~3 km

Min Depth 15 m 45 m 5 m 50 m / 10 m

• Developed at NRL coupled HYCOM/CICE applicationDeveloped at NRL coupled HYCOM/CICE application

- ESMF-based HYCOM provided by NRL-SSC- ESMF-based HYCOM provided by NRL-SSC

- ESMF-based CICE 4.0 provided by LANL- ESMF-based CICE 4.0 provided by LANL

- All coupling by NRL-SSC- All coupling by NRL-SSC

• HYCOM/CICE at NRLHYCOM/CICE at NRL

- Initially for Arctic-only domain and a Bering Sea - Initially for Arctic-only domain and a Bering Sea

domain for testing data assimilationdomain for testing data assimilation

- Soon for fully global domain- Soon for fully global domain

HYCOM/CICE 4.0 HYCOM/CICE 4.0 OverviewOverview

• State of the art sea-ice model State of the art sea-ice model - Multi-category ice thickness- Multi-category ice thickness - Energy conserving thermodynamics- Energy conserving thermodynamics - Energy-based ridging scheme- Energy-based ridging scheme - Elastic-viscous-plastic (EVP) ice dynamics- Elastic-viscous-plastic (EVP) ice dynamics

• Open Source ice modelOpen Source ice model - http://climate.lanl.gov/Models/CICE- http://climate.lanl.gov/Models/CICE

Los Alamos Sea Ice Model Los Alamos Sea Ice Model (CICE 4.0) (CICE 4.0)

0.720.72° Arctic P-grid DX (km)° Arctic P-grid DX (km)

• Run for 2003-2006Run for 2003-2006

• Arctic-only grid is a sub-region Arctic-only grid is a sub-region of the tripole gridof the tripole grid

- Bottom in the Atlantic, top in - Bottom in the Atlantic, top in the Pacificthe Pacific

• Atlantic and Pacific boundariesAtlantic and Pacific boundaries - Closed (no-ice) in CICE- Closed (no-ice) in CICE - Closed but with relaxation to - Closed but with relaxation to

climatology in HYCOMclimatology in HYCOM

• The model coastline is at the 50 The model coastline is at the 50 m isobath (closing the Bering m isobath (closing the Bering Strait)Strait)

• 3 hourly NOGAPS 0.53 hourly NOGAPS 0.5˚ ˚ atmospheric forcing fieldsatmospheric forcing fields

HYCOM/CICE HYCOM/CICE ARCc 0.72ARCc 0.72˚̊

HYCOM/CICE ARCc0.08 HYCOM/CICE ARCc0.08

Run for 2005-2008Run for 2005-2008

The model coastline is at the 10 The model coastline is at the 10 m isobath (Bering Strait open).m isobath (Bering Strait open).

3 hourly NOGAPS 0.5 degree 3 hourly NOGAPS 0.5 degree atmospheric forcing fieldsatmospheric forcing fields

OBs are forced by the 1/12OBs are forced by the 1/12° ° global HYCOMglobal HYCOM

Ocean model is initialized from Ocean model is initialized from 1/12˚ non-assimilative global 1/12˚ non-assimilative global HYCOMHYCOM

0.080.08° Arctic grid resolution (km)° Arctic grid resolution (km)

Background:Background:Arctic OceanArctic Ocean

60N

80N

045W

90E

180W

Fram Strait

Bering StraitAlask

a

Lom

onos

ov

Rid

ge

CB

EB

GIN Sea

Arctic Ocean Bathymetry

(NGDC ETOPO-2)

Can

ada

Russia

Arctic Ocean CirculationArctic Ocean Circulation

WHOI: www.whoi.eduWHOI: www.whoi.edu

Temperature, February 250 m, PHC 3.0Temperature, February 250 m, PHC 3.0

Beaufort Gyre Beaufort Gyre SignatureSignature

Signature of Deep Signature of Deep Convection in the Convection in the Greenland GyreGreenland Gyre

GDEM3, Salinity at 3000 mGDEM3, Salinity at 3000 m

The deep Canadian Basin is The deep Canadian Basin is saltier than the Eurasian saltier than the Eurasian BasinBasin

>34.95

<34.9

5

Analysis of ARCc 0.72Analysis of ARCc 0.72° ° 2003-2006 Run2003-2006 Run

HYCOM/CICEHYCOM/CICE ARCc 0.72ARCc 0.72˚̊ grid gridPHC 3.0PHC 3.0

Near-Surface Temperature, FebruaryNear-Surface Temperature, February

20032003 20062006

Near-Surface Salinity, FebruaryNear-Surface Salinity, February

20032003 20062006

HYCOM/CICEHYCOM/CICE ARCc 0.72ARCc 0.72˚̊ grid gridPHC 3.0PHC 3.0

WHOI: www.whoi.eduWHOI: www.whoi.edu

Annual Mean Near-Surface Velocity Annual Mean Near-Surface Velocity FieldField

North Atlantic Gyre does not North Atlantic Gyre does not seem to be reproduced in the seem to be reproduced in the modelmodel

Beaufort Gyre is in Beaufort Gyre is in placeplace

Transpolar Current is in Transpolar Current is in placeplace

250 m Fields 250 m Fields

from from

HYCOM/CICE ARCc 0.72HYCOM/CICE ARCc 0.72˚̊

HYCOM/CICE ARCc 0.08HYCOM/CICE ARCc 0.08˚̊

Temperature 250 m, FebruaryTemperature 250 m, February

20062006

Atlantic water flow Atlantic water flow along the shelf along the shelf breakbreak

ARCc 0.72ARCc 0.72˚̊ grid gridPHC 3.0PHC 3.0 20062006

ARCc 0.08ARCc 0.08˚̊ grid grid

Salinity 250 m, FebruarySalinity 250 m, February

20062006ARCc 0.72ARCc 0.72˚̊ grid grid

PHC 3.0PHC 3.0 20062006ARCc 0.08ARCc 0.08˚̊ grid grid

Depth of the Upper Atlantic Water (Depth of 0Depth of the Upper Atlantic Water (Depth of 0˚ ˚ Surface)Surface)

Atlantic water flow Atlantic water flow along the shelf along the shelf breakbreak

20062006ARCc 0.72ARCc 0.72˚̊ grid grid PHC 3.0PHC 3.0

20062006ARCc 0.08ARCc 0.08˚̊ grid grid

Arctic Ocean – Greenland – Arctic Ocean – Greenland – Norwegian Seas cross-section Norwegian Seas cross-section

HYCOM/CICE ARCc 0.72HYCOM/CICE ARCc 0.72°°

60N

80N

045W

90

E

180W

GDEM 3HYCOM/CICE ARCc 0.72˚

Salinity, February

045W

GDEM 3HYCOM/CICE ARCc 0.72˚

Temperature, February

GDEM 3HYCOM/CICE ARCc 0.08˚, 2006

Salinity, February

GDEM 3HYCOM/CICE ARCc 0.08˚, 2006

Temperature, February

SummarySummary

• Coupled HYCOM/CICE 4.0 in place Coupled HYCOM/CICE 4.0 in place

- ARCc0.72: ran for 4 years (2003-2006) initialized using PHC 3.0 (ARCc0.72) - ARCc0.72: ran for 4 years (2003-2006) initialized using PHC 3.0 (ARCc0.72)

- ARCc0.08: ran for 4 years (2005-2008) initialized using 1/12- ARCc0.08: ran for 4 years (2005-2008) initialized using 1/12° Global HYCOM° Global HYCOM

• Surface and deep water mass distribution modeled in ARCc 0.72Surface and deep water mass distribution modeled in ARCc 0.72˚ (and ˚ (and 0.08˚) 0.08˚) is similar to climatology is similar to climatology

• In both ARCc 0.72In both ARCc 0.72˚ and 0.08˚, the Atlantic layer in the Arctic Ocean˚ and 0.08˚, the Atlantic layer in the Arctic Ocean is is dislocated compared to observations: dislocated compared to observations:

- Atlantic layer is too deep in ARCc 0.72- Atlantic layer is too deep in ARCc 0.72˚ ˚

- Atlantic water does not penetrate into the Canadian Basin in ARCc 0.08- Atlantic water does not penetrate into the Canadian Basin in ARCc 0.08˚̊

Sea Ice from ARCc 0.08˚, 2005-2008

Sea Ice Simulation from Sea Ice Simulation from

HYCOM/CICE ARCc 0.72HYCOM/CICE ARCc 0.72°°

Sea Ice Drift FieldSea Ice Drift Field

HYCOM/CICE ARCc0.72 grid, 2006

Proshutinsky et al., 2008www.arctic.noaa.gov/reportcard/ocean.html

arctic.atmos.uiuc.edu/arctic.atmos.uiuc.edu/cryospherecryosphere

Sea Ice Concentration, ARCc 0.72Sea Ice Concentration, ARCc 0.72˚̊ September 1, 2006September 1, 2006

Potential Temperature

Salinity

Aaagaard et al., Thermohaline circulation in the Arctic Mediterranean Seas, JGR, 1985

Distribution of potential T and S along the section

Seasonal Sea Ice Thickness Seasonal Sea Ice Thickness (m)(m)

WinterWinter SummeSummerr

Seasonal Sea Ice Concentration Seasonal Sea Ice Concentration (m)(m)

WinterWinter SummeSummerr

Salinity, 10 m, PHC 3.0Salinity, 10 m, PHC 3.0

Anticyclonic Beaufort

Gyre

February August

Seasonal Signal Seasonal Signal

Simulated in Simulated in

HYCOM/CICE ARCc 0.72HYCOM/CICE ARCc 0.72°°

Seasonal Near-Surface TemperatureSeasonal Near-Surface Temperature

PHC 3.0HYCOM/CICE ARCc0.72 grid, 2003-2006

Winter

Summer

Seasonal Near-Surface SalinitySeasonal Near-Surface SalinityPHC 3.0HYCOM/CICE ARCc0.72 grid, 2003-2006

Winter

Summer

1) Analysis of 0.72 and 0.08 model runs 1) Analysis of 0.72 and 0.08 model runs performed by NRL SSCperformed by NRL SSC

2) Test runs with ARCc0.722) Test runs with ARCc0.72

3) Transition to ARCc0.083) Transition to ARCc0.08

4) AOMIP coordinated 50-year run of 4) AOMIP coordinated 50-year run of ARCc0.08 ARCc0.08

COAPS PlansCOAPS Plans

Two-way coupled HYCOM/CICE – Two-way coupled HYCOM/CICE – exchanges fields every 3 hoursexchanges fields every 3 hours

• HYCOM uses a 18 minute time step and exports:HYCOM uses a 18 minute time step and exports: - SST- SST - SSS - SSS - Surface currents- Surface currents

• CICE uses a 45 minute time step and exports:CICE uses a 45 minute time step and exports: - Ice concentration- Ice concentration - Ice-ocean stresses - Ice-ocean stresses - Actual Freeze/Melt Heat/Salt/Mass Flux- Actual Freeze/Melt Heat/Salt/Mass Flux - Solar radiation at ice base- Solar radiation at ice base

** Runs on three HPC systems: IBM p655+, SGI Origin ** Runs on three HPC systems: IBM p655+, SGI Origin 3900 and Cray XT33900 and Cray XT3

Stand-alone vs Coupled

• Stand-alone - CICE has simple bulk ocean mixed layer Relaxes to climatological SST and SSS Calculates an ice-ocean stress, based on zero ocean currents - HYCOM treats sea-ice as an “energy bank” No ice advection No ice-ocean stress (wind stress applied directly to the ocean)

• Best possible coupling: - HYCOM’s ocean CICE’s sea-ice - Ice-Ocean Stress identical in HYCOM and CICE - Ice-Ocean Fluxes identical in HYCOM and CICE

• Actual 2-way coupling: - Ice-Ocean Stress identical in HYCOM and CICE - Similar, but not identical, Ice-Ocean Fluxes CICE’s SST strongly relaxed to HYCOM SST HYCOM’s sea-ice concentration strongly relaxed to CICE sea-ice concentration - Fields exchanged every 3 hours

• Arctic dipole patch on standard Mercator globeArctic dipole patch on standard Mercator globe

• This tripole grid has many good propertiesThis tripole grid has many good properties - Rectilinear grid south of the Arctic patch- Rectilinear grid south of the Arctic patch - Grid aligned with the equator- Grid aligned with the equator - Same resolution in Arctic and Antarctic – if Arctic patch starts- Same resolution in Arctic and Antarctic – if Arctic patch starts about 47Nabout 47N - relatively smooth transition across the patch boundary- relatively smooth transition across the patch boundary

• The “full” tripole grid contains all locations twiceThe “full” tripole grid contains all locations twice - Just as a “full” periodic domain contains all locations an- Just as a “full” periodic domain contains all locations an infinite number of timesinfinite number of times

• Global: use the lower copy of each locationGlobal: use the lower copy of each location - Logically rectangular arrays- Logically rectangular arrays - Needs a special halo exchange on the top edge- Needs a special halo exchange on the top edge -- Includes a sign change for v-velocity-- Includes a sign change for v-velocity -- Some points still included twice (both copies must be-- Some points still included twice (both copies must be identical – consistency check)identical – consistency check)

Global Tripole Grid Global Tripole Grid

Zhang and Steele (JGR, 2007)

POP model, 1978HYCOM/CICE ARCc0.72 grid, 2006

Mean Horizontal Velocity Across Fram Mean Horizontal Velocity Across Fram StraitStrait

|U|<0.2

GDEM3 PHC 3.0

Salinity, February 250 mSalinity, February 250 m

Temperature, 10 m, PHC 3.0Temperature, 10 m, PHC 3.0

February August

Near-Surface Temperature, AugustNear-Surface Temperature, August

20032003 20062006HYCOM/CICEHYCOM/CICE ARCc 0.72ARCc 0.72˚̊ grid grid

PHC 3.0PHC 3.0

Near-Surface Salinity, AugustNear-Surface Salinity, August

20032003 20062006

HYCOM/CICEHYCOM/CICE ARCc 0.72ARCc 0.72˚̊ grid gridPHC 3.0PHC 3.0

Initial Field: Temperature at 250 m, Initial Field: Temperature at 250 m, JanuaryJanuary PHC 3.0HYCOM/CICE ARCc 0.72 grid

Initial Depth of the Upper Atlantic Water (Depth of 0Initial Depth of the Upper Atlantic Water (Depth of 0˚ ˚ Surface)Surface)

PHC 3.0, JuneInitial Field, ARCc 0.72, June