Solar Activity and Lunar Precessions Influence Extreme Sea-Level Variability in the US Atlantic and Gulf of Mexico Coasts

Along the Atlantic coast of the United States, interannual sea-level variations of up to 20 mm are superimposed regionally upon the global average sea-level rise (similar to 3 mm/year) from human-caused global warming. These variations affect the degree of coastal flooding and related damage during the highest annual tides. Interannual sea-level variations have been attributed to several atmospheric and oceanographic processes. In the present analysis, detrended tide gauge data isolate >5-year interannual variations. These variations can be reliably reconstructed (>77% of the variance explained) with Fourier coefficients that have frequencies related to lunar orbit (nodal and apsidal precessions) combined with solar activity. Although a causal relationship between astronomical forcing and extreme sea levels remains elusive, the reconstructions may provide an effective method for projections of extreme sea levels. Two reconstructions project that anomalously high sea levels may occur in the late 2020s, mid-2050s, early 2060s, early 2070s, and late 2090s.