Abstract The non‐closure of the global sea level budget, detected since 2017, stimulates the need to better understand limitations of satellite altimetry and gravimetry measurements, and breakdown in situ measurement contributions and gaps. Here, temperature and salinity profiles collected in the subtropical Northwest Atlantic Ocean between 2017 and 2022 by Deep Argo floats are used to partition steric sea level variability into contributions as a function of depth. Interannual steric sea level variability near the surface is of the same order of magnitude over the western boundary and abyssal plain, but fluctuations below 2,000 m over the western boundary are seven times larger and seem affected by local wind forcing. This analysis demonstrates how Deep Argo enables new evaluation of regional sea level budgets and comparison to geodetic products. Differences between float measurements and GLORYS12 highlight the need for more deep‐ocean measurements that can be assimilated in the development of ocean reanalysis products.

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