Modeling Dissolved and Particulate 230Th in the Canada Basin: Implications for Recent Changes in Particle Flux and Intermediate Circulation ...

• Main Authors: Yu, Xiaoxin, Allen, Susan, François, Roger, Grenier, Mélanie, Myers, Paul G., Hu, Xianmin
• Format: Text
• Language: English
• Published: American Geophysical Union 2022
• Subjects: Arctic; Arctic Ocean; canada basin; Climate change; Sea ice
• Online Access: https://dx.doi.org/10.14288/1.0406573; https://doi.library.ubc.ca/10.14288/1.0406573

Global climate change has had large impacts on the Arctic region including rapid reductions in sea ice and rapid increases in surface air temperatures. Documenting the consequences of these changes in the Arctic Ocean is difficult, however, because accessibility limits observations in space and time and aliases measurements. This problem can be alleviated by using geochemical tracers, which can act as natural integrators, allowing us to determine net changes over regions and years. One such tracer is 230Th. We use measurements and an off-line scavenging model forced by ANHA4, a regional configuration of the NEMO general circulation model, to investigate changes in the Canada Basin in the years 2002–2015. Observations show a clear decrease in 230Th in intermediate layers, particularly in the internal Canada Basin. The model reproduces the observed changes in 230Th concentration profiles. Using the model to determine the origin of the reduction shows that the decrease is due to both higher particle fluxes from ...