[AOS16-P02] Multi-year estimate of the air-sea CO2 flux in the Arctic with the use of the chlorophyll-a concentration
Keywords:CO2 flux, Arctic, chlorophyll-a, SOCAT
We examined the relationship between partial pressure of CO2 in the surface water (pCO2w) and chlorophyll-a concentration (Chl-a) in the Arctic. The relationship between pCO2w and Chl-a is negative where Chl-a < 1 mg m-3, but there is no significant relationship where Chl-a > 1 mg m-3. In the Greenland/Norwegian Seas, a relationship between pCO2w and Chl-a is strongly negative in spring and weakly negative in summer. Chl-a is higher in summer than in spring, while nutrient concentration is high in spring and low in summer there. A positive relationship between pCO2w and Chl-a is found in the Barents Sea in summer when Chl-a values decline while pCO2w remains at a relatively constant low level. In the Kara and East Siberian Seas and the Bering Strait, the relationships are positive because of high pCO2w and Chl-a water in the coastal region.
We estimated monthly air–sea CO2 flux in the Arctic north of 60°N from 1997 to 2014 by applying a self-organizing map technique with Chl-a, SST, SSS, SIC, xCO2a, and geographical positions. The addition of Chl-a as a training parameter enables us to improve the estimate of pCO2w through reproducing its decline in spring by biological production. A significant CO2 uptake of 180 ± 130 TgC yr–1 in the Arctic Ocean was obtained. This estimate has been much improved compared to a previous estimate thanks to the use of Chl-a, but to some extent also due to a higher number of CO2 data.
We estimated monthly air–sea CO2 flux in the Arctic north of 60°N from 1997 to 2014 by applying a self-organizing map technique with Chl-a, SST, SSS, SIC, xCO2a, and geographical positions. The addition of Chl-a as a training parameter enables us to improve the estimate of pCO2w through reproducing its decline in spring by biological production. A significant CO2 uptake of 180 ± 130 TgC yr–1 in the Arctic Ocean was obtained. This estimate has been much improved compared to a previous estimate thanks to the use of Chl-a, but to some extent also due to a higher number of CO2 data.