Accession Number:

ADA563391

Title:

Effects of Stencil Width on Surface Ocean Geostrophic Velocity and Vorticity Estimation from Gridded Satellite Altimeter Data

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV

Report Date:

2012-03-17

Pagination or Media Count:

19.0

Abstract:

Geostrophic velocity and vorticity are often estimated by finite difference differentiation of gridded sea surface height fields. Significant differences are obtained in the estimated velocity with the order of the difference operator of stencil width Speed-dependent biases of 10-20 are found for the traditional 3-point centered difference compared to wider, higher-order, stencils Additionally, wider stencils yield estimates of the anisotropy of velocity variance insensitive to the differences in grid spacing between two widely used altimeter products Three-point stencils yield incorrect anisotropies on the 14 anisotropic AVISO grid, we recommend the use of 7-point stencils The zonally-averaged, midlatitude eddy kinetic energy field, estimated with wider stencils, is nearly isotropic. Finally, the paper also examines the strengths and limitations of applying noise-suppressing differentiators versus classic centered differences to velocity estimation from altimeter data

Subject Categories:

  • Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE