Deep-Ocean Tides in the South-West Indian
Ocean: Comparing Deep-Sea Pressure
to Satellite Data
Leo R. M. Maas, Borja Aguiar-González and Leandro Ponsoni
Introduction
Tides have been known to humanity for thousands of years [6]. This knowledge was
based on coastal observations of sea surface elevation and associated currents. It was
not until the seventeenth century that tides were perceived as very long surface gravity waves that propagate not only along ocean boundaries but that also cross oceans
[19]. Observations on the coherent nature of tides, over scales of many hundreds of
kilometers or more, started in the nineteenth century [42]. These observations were
fraught with surprise, as the tidal field in the North Sea turned out to be much more
complex than expected. Its spatial amplitude and phase pattern could be rationalized only by anticipating the existence of amphidromic points: phase singularities at
nodal points where the sea surface elevation field vanishes, and around which crest
and troughs rotate [42]. Later, the appearance of amphidromes was recognized to be
a generic feature in rotating fluids, owing their existence to the Coriolis force that
acts transverse to the current. Amphidromic points are now a standard property in the
L. R. M. Maas ( ✉ )
Institute for Marine and Atmospheric Research Utrecht, Utrecht University,
Princetonplein 5, 3584 CC Utrecht, The Netherlands
e-mail: L.R.M.Maas@uu.nl
L. R. M. Maas
NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands
B. Aguiar-González
Department of Ocean Systems Sciences, NIOZ Royal Netherlands Institute
for Sea Research, Utrecht University, P.O. Box 59, 1790 AB
Den Burg, Texel, The Netherlands
e-mail: aguiar@nioz.nl
L. Ponsoni
Georges Lemaître Centre for Earth and Climate Research (TECLIM),
Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
e-mail: leandro.ponsoni@uclouvain.be
© Springer International Publishing AG, part of Springer Nature 2018
M. G. Velarde et al. (eds.), The Ocean in Motion, Springer Oceanography,
https://doi.org/10.1007/978-3-319-71934-4_12
147
Ocean: Comparing Deep-Sea Pressure
to Satellite Data
Leo R. M. Maas, Borja Aguiar-González and Leandro Ponsoni
Introduction
Tides have been known to humanity for thousands of years [6]. This knowledge was
based on coastal observations of sea surface elevation and associated currents. It was
not until the seventeenth century that tides were perceived as very long surface gravity waves that propagate not only along ocean boundaries but that also cross oceans
[19]. Observations on the coherent nature of tides, over scales of many hundreds of
kilometers or more, started in the nineteenth century [42]. These observations were
fraught with surprise, as the tidal field in the North Sea turned out to be much more
complex than expected. Its spatial amplitude and phase pattern could be rationalized only by anticipating the existence of amphidromic points: phase singularities at
nodal points where the sea surface elevation field vanishes, and around which crest
and troughs rotate [42]. Later, the appearance of amphidromes was recognized to be
a generic feature in rotating fluids, owing their existence to the Coriolis force that
acts transverse to the current. Amphidromic points are now a standard property in the
L. R. M. Maas ( ✉ )
Institute for Marine and Atmospheric Research Utrecht, Utrecht University,
Princetonplein 5, 3584 CC Utrecht, The Netherlands
e-mail: L.R.M.Maas@uu.nl
L. R. M. Maas
NIOZ Royal Netherlands Institute for Sea Research, Texel, The Netherlands
B. Aguiar-González
Department of Ocean Systems Sciences, NIOZ Royal Netherlands Institute
for Sea Research, Utrecht University, P.O. Box 59, 1790 AB
Den Burg, Texel, The Netherlands
e-mail: aguiar@nioz.nl
L. Ponsoni
Georges Lemaître Centre for Earth and Climate Research (TECLIM),
Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
e-mail: leandro.ponsoni@uclouvain.be
© Springer International Publishing AG, part of Springer Nature 2018
M. G. Velarde et al. (eds.), The Ocean in Motion, Springer Oceanography,
https://doi.org/10.1007/978-3-319-71934-4_12
147