Model-data assessment of Scotian Shelf carbon dynamics:

A spatially varied and biologically active system

Krysten Rutherford, Katja Fennel, Dariia Atamanchuk, Douglas Wallace, Helmuth Thomas, Ka Ki Kam

Department of Oceanography, Dalhousie UniversityOceanPredict, May 2019, Halifax

Model-data assessment of Scotian Shelf carbon dynamics 1

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 2

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 3

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

DIC OMPOM DOM

POM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 4

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 5

DIC OM

POM DOM

POM

CO2

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 6

+ lateral/along-shelf transport

DIC OM

POM DOM

POM

CO2

CO2

DIC, OM

land coastal & shelf seas open ocean

sediments

DIC, OM

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 7

Sea-Air CO2 Flux(mol C m-2 yr-1)

+ Source - Sink

Laruelle et al. 2014

Laruelle et al. 2015

Shadwick et al. 2011

Signorini et al. 2013

Scotian Shelf

-0.33 ± 0.25

- 0.25 ± 0.08

+ 1.42 ± 0.28

- 1.10 ± 0.25

Model-data assessment of Scotian Shelf carbon dynamics 8

Model-data assessment of Scotian Shelf carbon dynamics 9

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

How are biological processes impacting the carbon dynamics

on the ScotianShelf?

Model-data assessment of Scotian Shelf carbon dynamics 10

Surf

ace p

CO

2

Day

0 50 100 150 200 250 300 350200

300

400

500

600

(μat

m)

CARIOCA Buoy Observations (2009-2014)

Model-data assessment of Scotian Shelf carbon dynamics 11

DIC OMPOM DOM

POM

CO2

land coastal & shelf seas open ocean

sediments

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

Model-data assessment of Scotian Shelf carbon dynamics 11

+ lateral/along-shelf transport

DIC OM

POM DOM

POM

CO2

CO2

DIC, OM

land coastal & shelf seas open ocean

sediments

DIC, OM

DIC OM

POM DOM

land coastal & shelf seas open ocean

sediments

How are transport processes impacting the carbon dynamics on the

Scotian Shelf?

Model-data assessment of Scotian Shelf carbon dynamics 12

Condor Observations: surface pCO2 (μatm)

March 12, 2018 April 9, 2018 June 3, 2018

• 10 km horizontal resolution• 30 vertical layers• Physical B.C. from Urrego-Blanco &

Sheng (2012)• Biochemical B.C. from

observations• 3-hourly ECMWF ERA-Interim

atmospheric forcing• 12 major rivers• Tides• No ice• HSIMT advection scheme

Biogeochemical ROMS implementation for Atlantic Canada

Model-data assessment of Scotian Shelf carbon dynamics 13

Model-data assessment of Scotian Shelf carbon dynamics 14

0 100 200 300

Day

200

250

300

350

400

450

500

550

600

650

Surface pCO2

200

300

400

500

600

100 200 3000

Day

pC

O2

(uat

m)

CARIOCA Buoy:Observations (2009-2014) vs Model (1999-2001)

Model-data assessment of Scotian Shelf carbon dynamics 15

Condor observations (2018) vs model (2000): surface pCO2

March 12, 2018 April 9, 2018 June 3, 2018

March 19, 2000 April 3, 2000 September 27, 2000

Co

nd

or

Ob

serv

atio

ns

Mo

del

Res

ult

s

surface pCO2 (μatm)

surface pCO2 (μatm)

surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 15

Condor observations (2018) vs model (2000): surface pCO2

March 12, 2018 April 9, 2018 June 3, 2018

March 19, 2000 April 3, 2000 September 27, 2000

Co

nd

or

Ob

serv

atio

ns

Mo

del

Res

ult

s

surface pCO2 (μatm)

surface pCO2 (μatm)

surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 15

Condor observations (2018) vs model (2000): surface pCO2

March 12, 2018 April 9, 2018 June 3, 2018

March 19, 2000 April 3, 2000 September 27, 2000

Co

nd

or

Ob

serv

atio

ns

Mo

del

Res

ult

s

surface pCO2 (μatm)

surface pCO2 (μatm)

surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 15

Condor observations (2018) vs model (2000): surface pCO2

March 12, 2018 April 9, 2018 June 3, 2018

March 19, 2000 April 3, 2000 September 27, 2000

Co

nd

or

Ob

serv

atio

ns

Mo

del

Res

ult

s

surface pCO2 (μatm)

surface pCO2 (μatm)

surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 15

Condor observations (2018) vs model (2000): surface pCO2

March 12, 2018 April 9, 2018 June 3, 2018

March 19, 2000 April 3, 2000 September 27, 2000

Co

nd

or

Ob

serv

atio

ns

Mo

del

Res

ult

s

surface pCO2 (μatm)

surface pCO2 (μatm)

surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 16

CO2

DIC, OM

land coastal & shelf seas open ocean

sediments

DIC, OM

upwelling

Model-data assessment of Scotian Shelf carbon dynamics 17

2520151050Coastal upwelling evident as a thin band along the

coast of Nova Scotia, mirroring the high pCO2

observations

Surface temperature

(oC)

600500400300

(μatm)

Surface pCO2

Sept-27-2000

• Scaling up one station does not explain the entire Scotian Shelf due to important shelf-wide spatial variability.

• Both biological and transport processes are playing important roles in Scotian Shelf carbon dynamics.

• Our model helps to interpret observations and mechanistically understand the pCO2 dynamics.

Model-data assessment of Scotian Shelf carbon dynamics 18

SUMMARY

to be continued…

Model-data assessment of Scotian Shelf carbon dynamics 15

700

600

500

400

300Sept-27-2000

Surface pCO2 (μatm)

Model-data assessment of Scotian Shelf carbon dynamics 18

June-29-2000

Sept-27-2000 25

20

15

10

5

0

Surface temperature

Surface pCO2

700

600

500

400

300

(μatm)

(oC)

Model-data assessment of Scotian Shelf carbon dynamics 10

Surf

ace p

CO

2

Day

0 50 100 150 200 250 300 350200

300

400

500

600

(μat

m)

CARIOCA Buoy Observations

Based on single station: Scotian Shelf is source of CO2

(+1.15± 1.38 mol C m-2 yr -1)Sea-Air CO2 Flux(mol C m-2 yr-1)

Laruelle et al. 2014

Laruelle et al. 2015

Shadwick et al. 2011

Signorini et al. 2013

Scotian Shelf

-0.33 ± 0.25

- 0.25 ± 0.08

+ 1.42 ± 0.28

- 1.10 ± 0.25

Model-data assessment of Scotian Shelf carbon dynamics 1

0 100 200 300Day

200

300

400

500

600

Surf

ace p

CO

2

(μat

m)

Buoy Observations: (+1.15± 1.38)

Model at Buoy Location: (+1.13± 0.30)

Model over Scotian Shelf:(+0.37± 1.17)

Sea-Air CO2 Flux(mol C m-2 yr-1)

Model-data assessment of Scotian Shelf carbon dynamics 1

Sea-Air CO2 Flux(mol C m-2 yr-1)

Laruelle et al. 2014

Laruelle et al. 2015

Shadwick et al. 2011

Signorini et al. 2013

Scotian Shelf

-0.33 ± 0.25

- 0.25 ± 0.08

+ 1.42 ± 0.28

- 1.10 ± 0.25

0 100 200 300Day

200

300

400

500

600

Surf

ace p

CO

2

(μat

m)

Buoy Observations: (+1.15± 1.38)

Model at Buoy Location: (+1.13± 0.30)

Model over Scotian Shelf:(+0.37± 1.17)

Sea-Air CO2 Flux(mol C m-2 yr-1)

Model-data assessment of Scotian Shelf carbon dynamics 1

land coastal & shelf seas open ocean

sedimentsupwelling