Accession Number:

ADA523550

Title:

High-Altitude Aerogravity Survey for Improved Geoid Determination

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOSCIENCES DIV

Personal Author(s):

Report Date:

2006-01-01

Pagination or Media Count:

3.0

Abstract:

Shallow water littoral regions present unique challenges for Naval operations. Warfighter support in the littoral region is hampered by our inability to relate tide and ocean circulation models directly to nautical charts via an absolute vertical datum. Various water measurements of critical importance to the Navy such as tide gauges, ocean bottom pressureinverted echo sounders, satellite altimetry, and heights now easily measured by GPS are made with respect to different vertical reference frames tidal datums and ellipsoidal frames, and there is no mechanism for conversion from one frame to another. An accurate geoid can provide the vertical reference required to relate the various vertical reference frames. The geoid is the surface of equal gravitational potential that most closely approximates mean sea level in a motionless ocean located with respect to the ellipsoidal GPS reference frame. Historically, the gravity field had not been sufficiently determined to produce a geoid accurate enough to relate the reference frames. Since 2003, however, the Gravity Recovery and Climate Experiment GRACE satellite has revolutionized our ability to construct geoids by accurately resolving the long-wavelength component of the global gravity field to wavelengths as short as 350-400 km. NRL has been combining GRACE data with short-wavelength terrestrial, marine, and airborne gravity to create a geoid for the Gulf of Mexico accurate to 5 cm as compared with tide gauge data located by GPS surveys. NRLs interest in accurate geoid determination dovetails closely with the mission of NOAAs National Geodetic Survey NGS to maintain and evolve a National Spatial Reference System based on the most accurate geoid possible for North America. NRL has recently partnered with NGS to conduct high-altitude airborne surveys at critical locations along the Gulf Coast.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Geodesy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE