Accurate computation of geoid-quasigeoid separation in mountainous region – A case study in Colorado with full extension to the experimental geoid region

• DOI: 10.1515/jogs-2022-0128
• Publication Date: 2023-04-15T10:51:13Z
• Authors: Yan Ming Wang; Marc Veronneau; Jianliang Huang; Kevin Ahlgren; Jordan Krcmaric; Xiaopeng Li; David Avalos-Naranjo
• Keywords: Elevation (ballistics); Longitude; Free-air gravity anomaly; Vertical deflection

Abstract The geoid-quasigeoid separation (GQS) traditionally uses the Bouguer anomalies to approximate difference between mean gravity and normal along plumb line. This approximation is adequate in flat low elevation areas, but not high rugged mountains. To increase accuracy, higher order terms of corrections (potential gradient) were computed Colorado where 1 cm geoid computation experiment was conducted. Over an area 730 km by 560 ranges 932 4,385 m, potential correction (Pot. Corr.) reaches −0.190 m its root square (RMS) 0.019 m. gradient small has variation: RMS merely 0.003 varies from −0.025 0.020 In addition, anomaly disturbance causes about a 0.01 bias maximum 0.02 total range −0.135 0.180 with value for region. magnitude large enough negligible considering today’s cm-geoid requirement. After test Colorado, complete GQS term 1′ × grids experimental 2020 (xGEOID20), which covers region bordered latitude 0–85° north, longitude 180–350° east. land 0.119 1.3 increases respect height until 4,000 then decreases unexpectedly. At highest peaks (5,500–6,000 m) Denali Mount Logan, 0.08 0.189 at these are caused steep slopes around that produce Pot. Corr. topography. reach half meter those peaks.