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Abstract

The knowledge gap of exact vertical motion at tide gauges limits the quantification of geocentric sea-level variations. Vertical motion, which is insensitive to satellite altimetry, plausibly exhibits transient or non-linear coastal land subsidence signals varying at spatial scales much finer than coastal sea-level rise. Alternate vertical motion determinations using GNSS receivers collocated with tide gauges, and GPS imaging technique for vertical motion estimates, arguably may not be exactly measuring the vertical motion exactly at tide gauge locations. The exact geocenter motion, defined as Earth’s Center of Mass change relative to Center of Figure, arguably remain elusive. The ongoing viscoelastic rebound of the solid Earth due primarily to the deglaciation of Late Pleistocene ice sheets, the GIA geophysical processes, are not well-known, including the bedrocks beneath polar ice sheets, and seafloor. The knowledge gap of steric sea level covering all depths of the ocean remain large. The plausible constraints using fingerprint approaches for sea-level adjustment have not been realized, presumably due to uncertainties of pattern stationarity. While statistically significant sea-level accelerations are detected using long-term tide gauges, altimeter-era sea-level acceleration estimates at local scales remains inconclusive. Finally, evidence of multi-decadal ocean oscillations presence would further diminish the more exact sea-level acceleration estimates at regional scales. Here, we report our sea-level research in progress, addressing some of the aforementioned limitations. We present an updated sea-level reconstruction and preliminary results, which jointly estimate for vertical motion at tide gauge locations, and geocentric sea-level trends at the local scale over the last seven decades.