ECHAM5NEMO coupled model

1
Current state of ECHAM5/NEMO coupled model
Wonsun Park, Noel Keenlyside, Mojib Latif
(IFM-GEOMAR) René Redler (NEC CC Research
Laboratories) DRAKKAR meeting 25-26 January
2007, Grenoble, France
2
Outline

• Overview of the coupled model
• 500-yr long simulations
• Current state
• Summary and outlook

3
Overview of KCM

• Kiel Climate Model (KCM) ECHAM5/NEMO coupled
  model
• Component models
• AGCM ECHAM5 (T31L19, T63L31, T106L31), IPCC
  version
• OGCM NEMO (ORCA2 standard, ORCA05-DRAKKAR
  configuration), V1_12, NEMO2
• Coupler OASIS3 or OASIS4 within PRISM

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Two 500-yr experiments

• Same ORCA2 configuration
• NEMO v1_12
• Standard parameters
• LIM parameters (hiccrit0.3,0.6 angvg-15)
• Different ECHAM5 tuning parameters
• T31L19 resolution
• P53 IPCC cloud scheme and parameters
• P57 New cloud scheme (Tompkins, 2002)

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MOC 30N
Transport (11-yr runavg)
15 13 11 9 7
15 13 11 9 7
P57 New cloud scheme P53 IPCC parameters
160 140 120 100 80 60
160 140 120 100 80 60
Drake passage
6
TOA Radiation 2m-temp
P53 IPCC parameters P57 New cloud scheme
1.5
1.0
0.5
W/m2
7
SST biases
P57 New cloud scheme P53 IPCC
parameters
8
Nino3 spectra
51mn
34mn
9
Equatorial annual cycles
Observation New cloud IPCC parameters
10
Sea ice
Fraction , March
Ice area 106 km2
Thickness m, March
11
Ice dynamics test
angvg-25
angvg25

• Adopting turning angle of ice drift
• Removing island?
• Canadian archipelago hydrological model change
  , redigitizing?

T25 ang0 no islands
T25
12
Current coupling scheme

• NEMO2
• Separate choice of angvg for NH and SH
• Preliminary hydrological model tuning in ECHAM5
  concerning Canadian archipelago (need further
  investigation for changing mask in ORCA2?)
• All Albedos unified in ECHAM5 (sea ice as well)
• Coupling time step 1x, 4x, 12x/day
• Variable exchanged
• Ocean to atmosphere (7) SST, sea ice fraction,
  sea ice thickness, snow thickness, sea ice
  temperature, zonal-, meridional- ocean velocity
• Atmosphere to ocean (11) U-, V- wind stresses on
  u- and v-grids, total P-E, solid P-E, solar- and
  non-solar heat flux over water and ice, non-solar
  heat flux derivative

13
Current run
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Ongoing analysis

• Tropical variability from ECHAM5/NEMO coupled
  model (Paper in preparation)
• ENSO and MOC relationship on multidecadal scales
• Freshwater variability and MOC (with comparison
  to T42, T63 atmosphere)
• Comparison with existing standalone ORCA2
  simulations

15
Summary and outlook

• KCM prototype is available for coordinated
  experiments with standalone NEMO
• Two 500-yr long simulations with difference
  atmosphere configurations
• Stable climate ( lt1 W/m2 TOA net radiation)
• Importance of atmosphere forcing to ENSO spectra
• Still low MOC, cold bias over North Atlantic
• YR2007 Constructing higher resolution model
• ECHAM5 T63L31/T106L31 coupled to ORCA05 DRAKKAR
  configuration, OASIS4
• Standalone ECHAM5, NEMO, and coupled model
  experiments following scientific interests

16
Thanks
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Mixed layer depth
Previous (P57) Current
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Meridional Overturning Circulation Antarctic
Circumpolar Current
13Sv
MOC
P53
9Sv
ACC
J64
110Sv
95Sv