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Regional Models

U.S.A. (GEOID90)

  Author: D.G. Milbert     Created: 1990    Resp: D.R. Roman  
      Status: PUBLIC    
GEOID90 is the first high-resolution geoid model for the United States computed by the National Geodetic Survey (NGS). It is referred to the GRS80 normal ellipsoid. It has a 3'x3' spatial resolution from 24°N to 53°N and 230°E to 294°E. It is based on nearly 1.5 million terrestrial and ship gravity values, no data for Alaska, Hawaii and Puerto Rico are contained into the model. The geoid determination is based a convolution of gravity data and a spherical Stokes kernel, by exploiting a Fast Fourier Transform (FFT) technique. This computation is performed in the framework of a remove-restore procedure, where long wavelengths come from the OSU89B geopotential model. By comparing the GEOID90 model with GPS/levelling data, the resulting accuracy is about 10 cm (one sigma) over length scales of 100 km. Better accuracy is seen over shorter lengths.

D.G. Milbert (1991). GEOID90: A high-resolution geoid for the United States. EOS, Transactions American Geophysical Union, Vol. 72(49), pp. 545-554.
D.G. Milbert (1992). GEOID90: High-resolution geoid height model for the conterminous United States. SEG Technical Program Expanded Abstracts 1992: pp. 581-584.