A Modal Analysis of Currents in a Pacific Atoll Lagoon

Abstract

The results of an initial quantitative study to define the physical oceanography of Johnston Atoll's lagoon circulation is presented. A bathymetric data base of the Island has been manually digitized from Navigational charts. A numerical model designed to predict the seiche modes of basins in two and three dimensions, in elliptic and Cartesian coordinates is developed, which seems to represent accurately the free modes of oscillation observed in current meter records. The numerical model is suitable for applications using a personal computer equipped with MATLAB (4.0) or later, and has applicability to basins of arbitrary shape in two dimensions, and rectangular, elliptical or circular symmetry in three dimensions. An analysis of currents within the lagoon at Johnston Atoll shows highly polarized tidal flow, phase locked to the diurnal tide. Spectral energy content of current meter records show six fundamental oscillatory modes and harmonics of tidal components. Johnston atoll, Seiche, Circulation, Modal analysis, Oscillation numerical

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1994
Accession Number
ADA283721

Entities

People

  • Burton T. Palmer

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Cartesian Coordinates
  • Computer Programs
  • Computers
  • Databases
  • Differential Equations
  • Digital Data
  • Earth Sciences
  • Ecology
  • Geometry
  • Grids
  • Measurement
  • Modal Analysis
  • Oceanography
  • Personal Computers
  • Physical Oceanography
  • Three Dimensional
  • Two Dimensional

Readers

  • Control Systems Engineering.
  • Oceanography.
  • Urban Planning and Geography.