Subpolar Atlantic meridional heat transports from OSNAP and ocean reanalyses – a comparison

Winkelbauer, Susanna; Winterer, Isabella; Mayer, Michael; Fu, Yao; Haimberger, Leopold

doi:10.5194/os-22-629-2026

Articles | Volume 22, issue 1

https://doi.org/10.5194/os-22-629-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/os-22-629-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 1

Research article

|

16 Feb 2026

Research article |

| 16 Feb 2026

Subpolar Atlantic meridional heat transports from OSNAP and ocean reanalyses – a comparison

Susanna Winkelbauer, Isabella Winterer, Michael Mayer, Yao Fu, and Leopold Haimberger

Data sets

Meridional Overturning Circulation Observed by the Overturning in the Subpolar North Atlantic Program (OSNAP) Array from August 2014 to June 2020 Y. Fu et al. https://doi.org/10.35090/gatech/70342

Global Ocean Gridded L 4 Sea Surface Heights And Derived Variables Reprocessed 1993 Ongoing E.U. Copernicus Marine Service Information (CMEMS) https://doi.org/10.48670/moi-00148

Mass-consistent atmospheric energy and moisture budget monthly data from 1979 to present derived from ERA5 reanalysis J. Mayer et al. https://doi.org/10.24381/cds.c2451f6b

CERES Energy Balanced and Filled (EBAF) TOA and Surface Monthly means data in netCDF Edition 4.2.1 NASA/LARC/SD/ASDC https://doi.org/10.5067/TERRA-AQUA-NOAA20/CERES/EBAF_L3B004.2.1

The Arctic Ocean volume, heat and fresh water transports time series from October 2004 to May 2010 T. Tsubouchi et al. https://doi.org/10.1594/PANGAEA.909966

JRA-55: Japanese 55-year Reanalysis, Monthly Means and Variances Japan Meteorological Agency https://doi.org/10.5065/D60G3H5B

MERRA-2 tavgM_2d_flx_Nx: 2d,Monthly mean,Time-Averaged,Single-Level,Assimilation,Surface Flux Diagnostics V5.12.4, Greenbelt, MD, USA GMAO https://doi.org/10.5067/0JRLVL8YV2Y4

IAP global ocean heat content 1° gridded analysis product (IAPv4) L. Cheng et al. https://doi.org/10.12157/IOCAS.20240117.001

RFROM: Random Forest Regression Ocean Maps (v2.2) J. M. Lyman and G. C. Johnson https://data.pmel.noaa.gov/pmel/erddap/files/argo_rfromv22/

Global Ocean Ensemble Physics Reanalysis C. Desportes et al. https://doi.org/10.48670/moi-00024

Model code and software

susannawinkelbauer/StraitFlux: StraitFlux v1.1.0 (v1.1.0) Susanna Winkelbauer https://doi.org/10.5281/zenodo.14620858

Short summary

Ocean reanalyses combine models and observations to reconstruct past ocean conditions. We evaluate their performance against measurements from the OSNAP (Overturning in the Subpolar North Atlantic Program) section. While reanalyses capture long-term averages and broad circulation patterns, they miss some more regional features and variability. This highlights both their value and their limitations, stressing the need for improved observations and higher-resolution models.