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Regional Models

Colorado - USA (ColSHAWG2019)

  Authors: Y.M. Wang, et al.   Created: 2019    Resp: Y.M. Wang  
                       Status: PUBLIC   Licence: CC BY 4.0
The ColSHAWG2019 gravimetric quasi-geoid and geoid models have been computed by the US National Geodetic Survey (NGS). They have been worked out in the frame of the International Association of Geodesy Joint Working Group 2.2.2 "The 1 cm geoid experiment" and the so called "Colorado experiment". The area covered by the models is 251°E ≤ longitude ≤ 257°E, 36°N ≤ latitude ≤ 39°N with a grid spacing of 1' in both latitude and in longitude. The computation method is based on spherical harmonic analysis scheme. The airborne gravity data are combined with the reference model xGEOID17RefB to produce an enhanced reference spherical harmonic model. This model is then used in a remove-compute-restore procedure, computing residual height anomalies from terrestrial gravity data by using the Wong-Gore modification of the Stokes kernel (truncation degree equal to 980), also including the g1 term because of rugged mountains. Finally, the geoid undulations are obtained by adding the geoid/quasi-geoid separation term (based on the simple Bouguer anomalies) to the computed height anomalies. The accuracy of the quasi-geoid and geoid models, when compared against GSVS17 GPS/leveling, is equal to 2.3 cm in both cases.

Y.M. Wang, X. Li, K. Ahlgren, J. Krcmaric (2020). Colorado geoid modeling at the US National Geodetic Survey. Journal of Geodesy, 94, 106. DOI: 10.1007/s00190-020-01429-w