Comparison JRA-55 vs. CORE2

  1. ✓ HYCOM ocean model (version 2.2.99G) coupled with CICE v4.0

  2. ✓ JRA-55 Forcing 1958-2015 or CORE2 Forcing 1948-2007

  3. ✓ Large and Yeager bulk formulation (absolute wind for wind-stress)

  4. ✓  Initialized from PHC2

  5. ✓ SSS relaxation of 4 years/50m everywhere except 6 months/50m in Southern Ocean

  6. ✓ Salt flux normalization

  7. ✓ No surface relaxation to SST

  8. ✓ 41 layers

CORE2 1st cycle

JRA-55 1st cycle

JRA-55 6th cycle

CORE2 1st cycle

JRA-55 1st cycle

JRA-55 6th cycle

JRA-55

JRA-55

CORE2 1st cycle

SSMI/IceSat

SSMI/IceSat

ANTARCTIC Winter

JRA-55 6th cycle

Ice Cover

Ice Thickness

Ice Cover

Ice Thickness

ARCTIC Winter

SSMI/IceSat

ARCTIC Summer

SSMI/IceSat

ANTARCTIC Summer

Ice Cover

Ice Thickness

Ice Cover

Ice Thickness

  1. ✓ Not too many changes between cycles in Heat flux and PME except for the Labrador Sea  in JRA-55

Obs. (Cunningham et al. 2003): 136.7 +/- 7.8 Sv

                      JRA-55 6th cycle: 158.6 +/- 1.9 Sv

Obs. (Baringer & Larsen 2001): 32.2 +/- 3 Sv

                      JRA-55 6th cycle: 12.5 +/- 1.1 Sv

Obs. (Woodgate et al. 2005): 0.8 +/- 0.2 Sv

                  JRA-55 6th cycle: 1.0 +/- 0.1 Sv

Obs. (Sprintall et al. 2009): -15 Sv

               JRA-55 6th cycle: -16.2 +/- 1.3 Sv

Obs. (Schauer et al. 2008): -2.0 +/- 2.7 Sv

               JRA-55 6th cycle: -0.1 +/- 0.4 Sv


  1. ✓ Heat Flux 6th cycle:

JRA-55 : -0.23 +/- 0.84 W/m2

  1. ✓ Similar SST and SSS biases between JRA-55 and CORE2

  2. ✓ Labrador Sea SST bias similar in JRA-55 6th cycle and CORE2 1st cycle

  3. ✓ Slightly less SSS bias in Arctic in JRA-55 compared with CORE2

  1. ✓ More positive Temperature bias in JRA-55 1st cycle in the tropics than in CORE2

  2. ✓ More negative Salinity bias in JRA-55 1st cycle in the Arctic at 100m

At the end of the JRA-55 6th cycle:

  1. ✓ Increased biases at depth in each basin

  2. ✓ Less negative salinity bias in the Arctic at 100m 

  1. ✓ SST stable throughout simulation, SSS stabilized after 5 cycles after increasing by 0.2psu.

  2. ✓ Global Temperature is close/back to  its initial value as well as SSH

  1. ✓ Freshwater content in the Arctic stabilized after 5 cycles, slightly above its initial value.

  1. ✓ JRA-55 6th cycle 1988-2007 SSH looks reasonable

  1. ✓ After decreasing below 10Sv for 3 cycles, JRA-55 AMOC finally got back to reasonable values in the 4th cycle. The 5th and 6th cycle show a stable AMOC with a realistic interannual/decadal variability.

  2. ✓ Mean 1988-2007 JRA-55 6th cycle: 16.4 +/- 2.2 Sv


  1. ✓ Increase of the strength of the Global and Atlantic Northward heat transport  between JRA-55 1st cycle and 6th cycle

  2. ✓ JRA-55 cycle is close to CORE2 1st cycle

  1. ✓ Drake passage transport 20 Sv higher than observations but stable

  2. ✓ Florida Strait too low due to resolution

  3. ✓ Bering strait close to observations

  4. ✓Indonesian Throughflow not stable, still increasing, getting closer to observations.

  5. ✓ Fram strait Net transport too low and becoming northward instead of southward (as in CORE2)

  1. ✓ More/Better ice with JRA-55 in Arctic and Antarctic

  2. ✓ Antarctic ice extend still to low compared with Observations despite the strong SSS relaxation.

CORE2 1st cycle

JRA-55 6th cycle

CORE2 1st cycle

JRA-55 6th cycle

CORE2 1st cycle

JRA-55 6th cycle

Surface Heat Flux and Freshwater Flux

Surface SST and SSS biases

Temperature and Salinity biases