Results of latest HYCOM runs (NRL-RSMAS)

Z. Garraffo, T. Townsend, G.Halliwell, A. Wallcraft, L. Smith, W.Schmitz, H.

Hurlburt, E. Chassignet In collaboration with F. Schott

114 115 117 118

Visco2(nonlin) 0.1 0.1 0.05 0.05

Veldf2(linear) 0.0075 0.003 0.005 A2,.003

cbar .1 .1 .05 .05

Cb 3.e-3 3.e-3 2.e-3 2.e-3

topogr T08 T08 T08 T10

Veldf4=0.01

Sea surface height for expt 11.8

1 year: 3-4 north brazil current rings with surface signal;1 loop current ring detached

Mixed layer depth for expt 11.6

Reduced nonlin visc, bottom drag

Surface speed (1 yr mean) Reduced lapl mom mix

constant A2

Speed sig2=36.77 (~1500m) Reduced lapl mom mix

Reduced nonlin visc, bottom drag constant A2

Speed sig2=37.10 (near bottom) Reduced lapl mom mix

Reduced nonlin visc, bottom drag constant A2

Schmitz, 1996

Schott et al., JPO 2004

IFM , BIO moorings location

Section 43N

Reduced lapl mom mix

constant A2Reduced nonlin visc, bottom drag

uLSWLSWGFZWDSOWsum

15Sv 15Sv

16Sv 16Sv

5Sv 5 5

10Sv 2 5(15)

(7.5)

Speed sig2=36.77 (~1500m)

constant A2

43ºN, nowcast

25Sv

13Sv(18)

012

Section 43NObservations: Schott et al

Reduced nonlin visc, bottom drag

Reduced lapl mom mix

constant A2

5

2.2

2.6

4.9

Tot 9.8/15

2.8

1.2

1.2

2.3Tot 4.7/7.5

Tot 12.2/12.9

(transports in Sv)totals:upsw+Lsw+gfzw+dsowLsw+gfzw+dsow

Observations (Schmitz)

Surface eddy kinetic energy

Deep eddy kinetic energy

Observations (Schmitz)

Summary

Gulfstream characteristics are improved in simulations with lower viscosity

at 43N:Deep western boundary current was also improved.

Diffusion affects how the deep southward overturn flow is distributed across longitudes.

In 1 model year, expt 118 shows: 3-4 North Brazil current rings with surface

expression1 loop current ring detached

Plots in http://hycom.rsmas.miami.edu/internal/zulema