Oceanography (Jun 2012)
Mapping Low-Mode Internal Tides from Multisatellite Altimetry
Abstract
Low-mode internal tides propagate over thousands of kilometers from their generation sites, distributing tidal energy across the ocean basins. Though internal tides can have large vertical displacements (often tens of meters or more) in the ocean interior, they deflect the sea surface only by several centimeters. Because of the regularity of the tidal forcing, this small signal can be detected by state-of-the-art, repeat-track, high-precision satellite altimetry over nearly the entire world ocean. Making use of combined sea surface height measurements from multiple satellites (which together have denser ground tracks than any single mission), it is now possible to resolve the complex interference patterns created by multiple internal tides using an improved plane-wave fit technique. As examples, we present regional M2 internal tide fields around the Mariana Arc and the Hawaiian Ridge and in the North Pacific Ocean. The limitations and some perspective on the multisatellite altimetric methods are discussed.
