Carbon cycling and optics in the Gulf of Maine: Observations and Modeling

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Carbon cycling and optics in the Gulf of Maine
Observations and Modeling Joe Salisbury Doug
Vandemark Janet Campbell Fei Chai Huijie
Xue Amala Mahatavan Wade McGillis
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Goal Reduce uncertainty in carbon flux estimates
in the Gulf of Maine -Air-sea -Land-Coast -Oc
ean-Coast
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Gulf of Maine and associated watersheds
(left) UNH monthly transects (right)
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Observations
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UNH Field Component
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Spatial variability in continuous measurements
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Temporal (Interannual) Variability

Mean cross-shelf pCO2 for June-July
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Air - sea interaction at Wilkinson Basin D pCO2
(left), net flux (right)
Annual flux 12 to 20 gC/m2 Range set by K600
of Wanninkhof (1992) vs. Wanninkhof and McGillis
(1999)
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Modeling Efforts
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Xue et al., CSR, in press
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Modeled DIC (top) and Temperature (bottom)
variability Mahatavan et al, GBC (2004)
OPA model based on Madec et al. 1999
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Carbon, Silicate, Nitrogen Ecosystem
Model CoSiNE, Chai et al. 2002 Dugdale et al.
2002
Air-Sea Exchange
Small Phytoplankton P1
Micro- Zooplankton Z1
Biological Uptake
Total CO2 TCO2
Grazing
NO3 Uptake
NH4 Uptake
Predation
Nitrate NO3
Iron
Excretion
Ammonium NH4
N-Uptake
Meso- zooplankton Z2
Fecal Pellet
Advection Mixing
Iron
Grazing
Fecal Pellet
Diatoms P2
Lost
Iron
Detritus-N DN
Detritus-Si DSi
Si-Uptake
Sinking
Physical Model
Silicate Si(OH)4
Dissolution
Sinking
Sinking
Chai et al., DSR 1996
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Comparison between Model result and SeaWiFS data,
April 2004
SeaWiFS Derived Chlorophyll
Modeled Surface Chlorophyll
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SeaWiFS Chlorophyll Climatology April (1998 -
2004)
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Time series comparison
EMCC
WMCC
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High Resolution Circulation Modeling and Remote
Sensing
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Gulf of Maine Circulation Model (H. Xue, UMO)
Sea Surface Salinity (psu) (3/17/05 1000 EST)
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Gulf of Maine Circulation Model (H. Xue, UMO)
Sea Surface Temp (oC)
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MODIS Assessment of pCO2
pCO2 (matm) (3/17/05 1030 EST)
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Net Ecosystem Metabolism (mg L-1 d -1 ) 3/17/05
1000EST
Estimated from Modeled Alkalinity MODIS
pCO2 Modeled DIC
NEM (mg L-1 d -1 ) estimate on 3/17/05 based on
modeled alkalinity and DICB derived by
satellite-retrieved pCO2 and modeled SST and SSS.
n126 RSME 5.7 (mg L-1 d -1 ) , r2 0.59
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Carbon and optics
pCO2 retrieval based on classification of optical
provinces
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Final comments Off to a good start - team
assembled, growing database of quality
measurements Modeling and remote sensing of
carbon parameters encouraging Budgets and error
estimates forthcoming The end - thanks