Monthly sea-level residual correlation had no clear pooled change at 101 gauges between 1960-1989 and 1995-2024

We tested whether monthly sea-level residuals became more persistent at 101 PSMSL gauges between 1960-1989 and 1995-2024. We reused a published fixed sample and removed separate linear trends and month effects. Equal weight for 33 occupied 10-degree cells gave a lag-one correlation change of -0.02095, from 0.44688 to 0.42593. The conditional 95% three-year block limits were -0.07130 to +0.03576. Weighted refits used 1,999 common-year draws and original month pairs. One- and five-year blocks, quadratic trends and stricter missing-day rules left the sign uncertain. A secondary 12-month decrease had an interval below zero with equal-gauge weights, but not with equal-cell weights. The result does not establish global change, a physical recovery time or flood risk. Sparse southern coverage, long climate dependence, pair-weight assumptions and source changes limit inference. Code, exact input rows, source hashes, all draw differences, a figure and passed numerical and source audits are included.

sea level · persistence · PSMSL · monthly correlation · block bootstrap · null result