Abstract. This study applies a neural network technique to produce maps
of oceanic surface pCO2 in Prydz Bay in the Southern
Ocean on a weekly 0.1∘ longitude × 0.1∘ latitude
grid based on in situ measurements obtained during the 31st CHINARE cruise
from February to early March 2015. This study area was divided into three
regions, namely, the “open-ocean” region, “sea-ice” region and “shelf” region. The
distribution of oceanic pCO2 was mainly affected by
physical processes in the open-ocean region, where mixing and upwelling were
the main controls. In the sea-ice region, oceanic pCO2
changed sharply due to the strong change in seasonal ice. In the shelf
region, biological factors were the main control. The weekly oceanic
pCO2 was estimated using a self-organizing map (SOM) with
four proxy parameters (sea surface temperature, chlorophyll a
concentration, mixed Layer Depth and sea surface salinity) to overcome the
complex relationship between the biogeochemical and physical conditions in
the Prydz Bay region. The reconstructed oceanic pCO2 data
coincide well with the in situ pCO2 data from
SOCAT, with a root mean square error of 22.14 µatm. Prydz Bay
was mainly a strong CO2 sink in February 2015, with a monthly
averaged uptake of 23.57±6.36 TgC. The oceanic CO2 sink is
pronounced in the shelf region due to its low oceanic
pCO2 values and peak biological production.