Amplitude and phase of the 11-yr term in sea-level: Europe

Summary. The 11-yr solar cycle term in sea-level is further elucidated by single-and two-channel high resolution signal processing techniques applied to 37 European height H of sea-level records. In agreement with earlier analysis the period and amplitude are 10.6 ± 0.3 yr and 10.3 ± 4.8 mm. New results are as follows: in view of the recently detected 11-yr term in Earth rotation Δ T = ET — UT, cross-spectra of the H records with Δ T were computed. At the solar cycle period H lags Δ T by 0.7 ± 0.5 yr; since AT lags the change in length of day Δ(10 d) by 2.7 yr the result is that H lags Δ(10 d) by 3.4 ± 0.5 yr. The continuum spectrum of H and Δ T has a high coherency and zero phase from the solar cycle down to a period of 40 yr, although this relation cannot be causal. We propose that the circumpolar vortex of westerly winds is the common forcing function for the H and Δ T discrete solar cycle signal and a significant portion of the long-period continuum in European waters.