05 Jun 2023
 | 05 Jun 2023

Uncertainty in the evolution of northwest North Atlantic circulation leads to diverging biogeochemical projections

Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John

Abstract. The global ocean’s coastal areas are rapidly experiencing the effects of climate change. These regions are highly dynamic, with relatively small-scale circulation features like shelf-break currents playing an important role. Projections can produce widely diverging estimates of future regional circulation structures. Here, we use the northwest North Atlantic, a hotspot of ocean warming, as a case study to illustrate how the uncertainty in future estimates of regional circulation manifests itself and affects projections of shelf-wide biogeochemistry. Two diverging climate model projections are considered and downscaled using a high-resolution regional model with intermediate biogeochemical complexity. The two resulting future scenarios exhibit qualitatively different circulation structures by 2075 where along-shelf volume transport is reduced by 70 % in one of them and while remaining largely unchanged in the other. The reduction in along-shelf transport creates localized areas with either amplified warming (+3 °C) and salinification (+0.25 units) or increased acidification (-0.25 units) in shelf bottom waters. Our results illustrate that a wide range of outcomes is possible for continental margins and suggest a need for accurate projections of small-scale circulation features like shelf-break currents in order to improve the reliability of biogeochemical projections.

Krysten Rutherford et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-987', Anonymous Referee #1, 17 Jul 2023
  • RC2: 'Comment on egusphere-2023-987', Anonymous Referee #2, 23 Jul 2023
  • RC3: 'Comment on egusphere-2023-987', Anonymous Referee #3, 29 Jul 2023

Krysten Rutherford et al.

Krysten Rutherford et al.


Total article views: 335 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
230 88 17 335 34 6 6
  • HTML: 230
  • PDF: 88
  • XML: 17
  • Total: 335
  • Supplement: 34
  • BibTeX: 6
  • EndNote: 6
Views and downloads (calculated since 05 Jun 2023)
Cumulative views and downloads (calculated since 05 Jun 2023)

Viewed (geographical distribution)

Total article views: 334 (including HTML, PDF, and XML) Thereof 334 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 22 Sep 2023
Short summary
We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.