Ocean‐tide loading and Earth tides around New Zealand

Abstract

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.

Keywords:

• tides
• ocean‐tide loading
• Earth tides
• tidal constituents