Ocean‐tide loading and Earth tides around New Zealand

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Cotidal charts of ocean‐tide loading and Earth tides for the New Zealand region are presented for eight constituents (M2, S2, N2, K2, K1, O1, P1, Q1). Ocean‐tide loadings were calculated by evaluating a convolution integral between tide models (global and local) and a Green's function that describes the response of the Earth to tide loading. Earth tides were calculated from the tide‐generating potential. The ocean‐tide loadings are a maximum to the north of New Zealand for M2 and N2 and in the western Cook Strait region for S2 and K2. The diurnal ocean‐tide loadings are dominated by amphidromes east of the Chatham Islands (K1 and P1) and north of Bay of Plenty (O1 and Q1). Diurnal Earth tides are a maximum at 45°S and vary only slightly in amplitude and phase over New Zealand; semidiurnal Earth tides increase from south to north.