ICOS Science Conference 2022: Day 1, Session 6

1. Estimating air sea CO2
flux on the European
shelf
MEIKE BECKER, ARE OLSEN
GFI, UNIVERSITY OF BERGEN
BJERKNES CENTRE FOR CLIMATE RESEARCH

2. Overarching goal: Determining
the ocean carbon sink
2
ATMOSPHERE: 46%
OCEAN: 23%
LAND: 31%
Friedlingstein et al, 2022

3. 3

4. 4
› Open ocean CO2 flux maps
› 8 different products in Global
Carbon Budget
› 10 different products in RECCAP 2
Friedlingstein et al, 2022

5. 5
Random Forest regressions

6. 6
Random Forest regressions

7. 7
Random Forest regressions
Training
dataset
Random
Forest
Product
Prediction
dataset

8. Global CO2 database
for surface ocean CO2
measurements
8
SOCAT database
8
8

9. Global CO2 database
for surface ocean CO2
measurements
9
SOCAT database
9
9

10. 10
Random Forest regressions
Training
dataset
pCO2
data
Co-located driver
data e.g. SST, Chl,
MLD
Random
Forest
Full driver data
e.g. SST, Chl, MLD
pCO2 maps
Prediction
dataset Product

11. 11
RMSE / matm R2
Barents Sea 9.9 0.93
Nordic Seas 15.6 0.89
North Sea 19.0 0.85
Baltic Sea 33.5 0.92
Atlantic shelf / Northern 15.5 0.84
Atlantic shelf / Southern 20.2 0.81
Mediterranean 11.4 0.95
Coast definition: 500m water depth or 100km from shore
Spatial resolution: 0.125˚ x 0.125˚
Temporal resolution: monthly
Table 2: RMSE and R2 of the Random Forest pCO2 mapping routine
Results of the RF regression: fCO2 maps

12. 12
Seasonal variations and
variability in fCO2
Month with
minimum
fCO2
Month with
maximum
fCO2

13. 13
Seasonal variations and
variability in fCO2
Month with
minimum
fCO2
Month with
maximum
fCO2

14. 14
Seasonal variations and
variability in CO2 flux
Month with
minimum
CO2 flux
Month with
maximum
CO2 flux

15. 15
Seasonal variations and
variability in CO2 flux
Month with
minimum
CO2 flux
Month with
maximum
fCO2 flux

16. 16
› Sinks:
• Barents Sea
• Nordic Seas
• Northern and Central North Sea
• Atlantic shelf
› Sources:
• Southern North Sea and English Channel
• Baltic Sea
• Mediterranean
Air-Sea flux 2010-2020
FCO2 / gC yr-1 m-2

17. 17
› Increasing sink strength:
• Northern Atlantic shelf
• Barents Sea
Time Series of air-sea CO2 flux

18. 18
› We can use Random Forest regressions to produce
precise maps of coastal pCO2 and air-sea CO2 flux
› Large variability between regions
› Most regions on the European shelf are a net sink for
CO2
› Some of these are increasing in strength
Conclusions

19. 19

20. 20
Thanks to everyone who
contributed to the SOCAT
database!
Do you have any
questions?

21. ICOS
Integrated Carbon Observation System
› Europeisk forskningsinfrastruktur
› Målinger av CO2 I atmosfære, hav og land økosystemer
› 34 atmosfærs stasjoner
› 21 hav stasjoner
› 71 Økosystem stasjoner
21

22. ICOS Norge - Marine network
22
Kronprins Haakon (KPH)
Nuka Arctica (until April 2020) /
Tukuma Arctica (from October 2020)
Trans Carrier
GO Sars
SOOP-Bergen Kirkenes