Comparison of the Atlantic meridional overturning circulation between 1960 and 2007 in six ocean reanalysis products

Improving our understanding of and ability to predict the Atlantic Meridional Overturning Circulation is an important goal because the AMOC is linked to Atlantic hurricanes and precipitation patterns over Africa, India, North America, and Europe. However, carefully collected observations specifically intended to measure the AMOC go back only about ten years, so reanalysis products are used to compensate for limited observations when studying the AMOC’s decadal variations.
A new CVP-supported study published in Climate Dynamics compares six ocean reanalyses produced under different conditions (forcings, models) to determine how they represented the variability characteristics and mean of the AMOC.
Karspeck et al. find that in products constrained using subsurface ocean data, the mean strength and variance of the AMOC is enhanced compared to reference simulations without subsurface constraints and to those forced by an atmospheric dataset (CORE-II). Additionally, the products with subsurface constraints are less consistent in year-to-year AMOC changes.
These outcomes suggest that careful consideration should be given when selecting reanalysis products, and that more work must be done to understand how these dissimilarities in reanalysis products are affecting the goal of improving decadal prediction.
To access the full paper, visit: dx.doi.org/10.1007/s00382-015-2787-7