Is there a hot spot of sea-level rise acceleration along the mid-Atlantic United States? A Gaussian process decomposition of tide gauge records

TL;DR

This study uses Gaussian process modeling to analyze tide gauge data, revealing a potential sea-level rise acceleration along the mid-Atlantic U.S. coast that requires further observation to confirm its long-term significance.

Contribution

The paper introduces a Gaussian process decomposition method to differentiate short-term variability from long-term trends in tide gauge records, clarifying sea-level rise patterns.

Findings

Faster-than-global sea-level rise observed since ~1975 in the mid-Atlantic.

Acceleration may reflect either a long-term trend or ocean variability.

Current climate indices are within historical variability ranges.

Abstract

To test a hypothesized faster-than-global sea-level acceleration along the mid-Atlantic United States, I construct a Gaussian process model that decomposes tide gauge data into short-term variability and longer-term trends, and into globally-coherent, regionally-coherent and local components. While tide gauge records indicate a faster-than-global increase in the rate of mid-Atlantic U.S. sea-level rise beginning ~1975, this acceleration could reflect either the start of a long-term trend or ocean dynamic variability. The acceleration will need to continue for ~2 decades before the rate of increase of the sea-level gradient between the mid-Atlantic and southeastern U.S. can be judged as very likely unprecedented by 20th century standards. However, the gradient is correlated with the Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and Gulf Stream North Wall indices, all of which are currently within the range of past variability.