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Assessing Eddying (1/12°) Ocean Reanalysis GLORYS12 Using the 14‐yr Instrumental Record From 59.5°N Section in the Atlantic
Author(s) -
Verezemskaya Polina,
Barnier Bernard,
Gulev Sergey K.,
Gladyshev Sergey,
Molines JeanMarc,
Gladyshev Vsevolod,
Lellouche JeanMichel,
Gavrikov Alexander
Publication year - 2021
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2020jc016317
Subject(s) - climatology , thermocline , hydrography , zonal and meridional , thermohaline circulation , context (archaeology) , mesoscale meteorology , forcing (mathematics) , ocean gyre , geology , ocean heat content , environmental science , oceanography , paleontology , subtropics , fishery , biology
Abstract The eddy‐resolving (1/12°) global ocean reanalysis GLORYS12 is assessed against 14 years (2002–2015) of independent hydrographic observations collected at 59.5°N in the North Atlantic. Two multi‐observations statistical analyses, ISAS‐15 and ARMOR‐3D, and an eddy‐permitting (1/4°) reanalysis, GLORYS025, also contribute to this comparison. The mean thermohaline structure along the 59.5°N section revealed by the observations is well‐reproduced by GLORYS12, except for the overflow waters. A good agreement with observations is found for linear trends over the whole period, exhibiting a dipole‐like pattern with a cooling/freshening in the main thermocline and a warming/salinization below. However, localized discrepancies with observations suggest the need for improvement in the reanalysis system (especially in the overflows representation and the consistency between the forcing and data assimilation system) and the deep observational array. The reanalysis reliably represents the ocean heat content in the upper 700‐m layer but shows significant differences with observations between 700 and 2,000 m. The meridional volume and heat transports across the 59.5°N section are compared for years when ADCP observations were available. The reanalysis does not reproduce the variability observed in the western boundary current but agrees well with observed transports in the other parts of the section. The reanalysis reproduces the major mesoscale eddy features that contribute to the meridional transport and provides the large‐scale context of their location. The analysis of time correlation at all measurement points demonstrated that GLORYS12 is the most accurate among the analyzed datasets used in this study to represent and explain the observed ocean characteristics and variability along that section.