EGU25-20507, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-20507
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Sensitivity on the AMOC estimate to the choice of data used at the RAPID 26N array
Tillys Petit1, David Smeed1, Jules B. Kajtar1, Bablu Sinha1, Adam Blaker1, Darren Rayner1, Shane Elipot2, William Johns2, Denis L. Volkov3, Ryan H. Smith3, Nick Higgs4, and Ben Moat1
Tillys Petit et al.
  • 1National Oceanography Centre, Southampton, UK
  • 2Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL, USA
  • 3Atlantic Oceanographic and Meteorological Laboratory, NOAA, Miami, FL, USA
  • 4Cape Eleuthera Institute, Bahamas

Direct measurements of the Atlantic Meridional Overturning Circulation (AMOC) and meridional heat transport (MHT) are necessary to better understand the impact of anthropogenic greenhouse gas emissions on the global climate system. The RAPID-MOCHA-WBTS array at 26°N is the only trans-Atlantic observing system to provide 20 years of continuous measurements of the AMOC and MHT. While the design of the array has continuously evolved as our understanding of the AMOC has advanced, and as new technologies have become available, a goal now is to design a lower-cost and more sustainable observing system to continue AMOC estimations at high accuracy. Using the RAPID array data and ocean reanalyses, we evaluate the sensitivity of the AMOC to the choice of data included in its estimation. We find that the variability of the volume transport in the upper 3000-m of the water column exceeds what can be captured by synoptic hydrographic data or ocean reanalysis. However, the deep interior moorings along the eastern boundary and Mid-Atlantic ridge can be replaced by hydrographic data from repeat trans-Atlantic sections to reliably estimate the AMOC. A high-resolution ocean model is used to quantify the long-term uncertainty of using hydrographic data at the RAPID array on the AMOC estimation. It shows that the uncertainty is small  as compared to the RAPID AMOC accuracy and that using hydrographic data does not change the significance of the observed AMOC trend.

How to cite: Petit, T., Smeed, D., Kajtar, J. B., Sinha, B., Blaker, A., Rayner, D., Elipot, S., Johns, W., Volkov, D. L., Smith, R. H., Higgs, N., and Moat, B.: Sensitivity on the AMOC estimate to the choice of data used at the RAPID 26N array, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20507, https://doi.org/10.5194/egusphere-egu25-20507, 2025.