(I) Observations (NODC data)
Sea surface TS
Mixed layer
NO3
(II) MICOM model runs year 100 (40 for NO3/DON)
(A) COADS forcing
Sea surface TS
Mixed layer
Sea surface velocity
Euphotic zone NO3/DON , NO3 exponential decay
DON refractory:semi-labile 50:50% ;
6-18 years refractory DON decay time scale (mixed layer/euphotic zone only)
Constant split
PON:DON 50:50%
Export production
and DON semi-labile ratio (case 1 PON:DON 50:50% )
Variable split
PON:DON 20:80% in N poor environment (N<0.5), 80:20% in N rich environment
Export production
and DON semi-labile ratio (case 2 PON:DON 20:80% )
(B) COADS forcing, NO3 decay ~ alpha*[I/(I+Io)*N/(N+No)], Io=10 W/m^2, No=0.1
alpha - max. production rate (Ep_max), I(lat,day) - daily mean short wave radiation spread over 24h
I(z) = Isurf.exp(-z/z*); z*=10m. Remineralisation depth 400m
Nutrient calculations every 12h, Max. production rate 5x10^-7 umol/(kg.s),
DON refractory/semi-labile 50:50%.
Note the different DON colour bar!!
1) Variable split: PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 80:20% in NO3 rich.
NO3 DON
Export production
and DON semi-labile ratio
4 pannel plot
No refractory DON
2) Constant split: PON:DON 50:50%.
NO3 DON
Export production
and DON semi-labile ratio
3) Variable split: PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich.
NO3 DON
Export production
and DON semi-labile ratio
(C) ECMWF forcing, NO3 decay ~ alpha*[I/(I+Io)*N/(N+No)], Io=10 W/m^2, No=0.1
alpha = 5x10^-7 [umol/(kg.s)]; I(lat,lon,hour) - short wave radiation contains daily cycle (calculated every hour).
1)
Variable split:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 80:20% in NO3 rich.
2)
Variable split:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich.
3)
Constant split:
PON:DON 20:80% everywhere.
Variable NO3 limiting term: No=0.1, alpha=3x10^-7 if N<0.5; No=1.5, alpha=10x10^-7 if N>0.5
Variable split:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich.
Cloud data used in short wave radiation fluxes.
Variable split:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich, monthly cloud data from ISCCP.
Constant split:
PON:DON 20:80% everywhere, monthly cloud data from ISCCP.
Variable spliti, Io=30W/m^2:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich, monthly cloud data from ISCCP.
Time series
Zonally integrated NO3/DON fluxes
Net NO3/DON fluxes
Nutrient flux sections
Data
Model NO3
Model DON
Data/model N-S sections
AMT10/14 N-S sections
Variable split, Io=10W/m^2:
PON:DON 20:80% in NO3 poor environment (<0.5 umol/kg), 50:50% in NO3 rich, monthly cloud data from ISCCP. Increased southern boundary N relaxation time scale (180 days).
N_rich=5:
Same as above, but NO3 poor environment defined as N<5.0 umol/kg.
Transport & DIN/DON budgets.
Nrich = 5
;
Nrich = 0.5
PDF format
of paper figures
III. Nutrient Streams & recent experiments
Sigma_0 , Sigma_2 comparison:
Sigma_0:
Euphotic zone fields; &
budgets
Sigma_2:
Euphotic zone fields; &
budgets
PON export
estimates (paper Fig. 8 colour version).
Nutrient streams
NO3 observations: NO3 N-S
section; NO3 E-W sections:
Set1
; Set2
Model NO3
E-W sections
and
isopycnal plots
NO3 flux density plots:
36N
; upper 2000m
E-W sections
NCEP runs: default model run for 20 years with ECMWF monthly mean forcing (climatological mode).
Another 15 years run with NCEP monthly forcing for the period 1990 - 2004 (interannual variability):
Subtropical; &
subpolar
timeseries.
Model
timeseries in BATS region.
Same period of 15 years from the default run - ECMWF monthly mean forcing (perpetual climatological year):
Subtropical; &
subpolar
timeseries.
Model
timeseries in BATS region.
BATS
timeseries. Monthly means, based on BATS data. The fields are averaged over upper 100m, but in most cases only 1-2 measurements around 100m exist.
Lagrangian tracers:
Fig. 1
; Fig. 2
; Fig. 3
Eulerian model tracers:
Gulfstream tracers
at the layer of release.
Gulfstream tracers
at the Mixed Layer.
Gulfstream tracers sections
Northern ML tracer
Particle flux included
Gulfstream tracer
;
Southern boundary tracer
Nutrient stream
IV. Latest runs
NCEP monthly mean forcing, sigma 2, 60 years dynamical model spin-up. PON:DON 35:65% (NO3 rich) 50:50% (NO3 poor environment); maximum export rate 1.2x10^-6 [umol/(kg.s)].
Coarse resolution 1.4 deg. model, year 100 annual mean
Euphotic zone (EZ) fields
(GBC paper default experiment)
Seasonal and inter-annual Nitrate model variability movie (~10 MB)
High resolution 0.23 deg. model: year 66
annual mean EZ fields
; year 66 January EZ snapshot
;
Year 62 - 66 January EZ snapshots;
Year 62 - 68 January EZ snapshots;
