A 2016 slope term made the Atlantic-Pacific steric acceleration contrast uncertain in 2005-2025

We tested an Atlantic-minus-Pacific acceleration contrast in total-minus-thermal steric sea level. We used 84 seasons of NOAA upper-700-m basin estimates in 2005-2025. A quadratic time fit gave -0.0802 mm/year squared, with conditional 95% three-year block limits of -0.1095 to -0.0500. Other block lengths and two shorter windows retained a negative contrast. A post hoc fit with a 2016 slope term gave +0.0576, with limits of -0.0242 to +0.1389. A level term alone had little effect. Thus the short record does not separate smooth acceleration from a slope change. The result does not show a salinity bias or a physical cause. One product, limited depth, source error, serial dependence and time-model choice limit inference. Code, aggregate evidence, uncertainty draws, source hashes, independent checks and figures are included.

steric sea level · salinity · acceleration · Atlantic · Pacific · model sensitivity