Estimation of vertical datum offset for the south african vertical datum, in relation to the international height reference system

Matthews Siphiwe, Mphuthi (author), Patroba Achola, Odera (author)

The vertical offset and the geopotential value over South Africa is estimated on the four fundamental benchmarks in relation to the international height reference system (IHRS). It is estimated to obtain discrepancies between the South African local vertical datum (WP) and the global vertical datum (W0 ). A single-point-based geodetic boundary value problem (GBVP) approach was used following Molodensky theory for estimating the height anomalies from the disturbing potential (TP ) using Bruns%s formula. The gravity potential at each tide gauge benchmark (TGBM) in South Africa deviates from the potential of the global reference surface by 0.589,-1.993,-2.593 and 2.154 m2 s -2 for Cape Town, Port Elizabeth, East London and Durban, respectively. The corresponding vertical datum offsets between the international height reference system and the four fundamental benchmarks over South Africa are 6.013, -20.347, -26.478, and 21.996 cm for Cape Town, Port Elizabeth, East London and Durban, respectively. These offsets can be used for the unification of the South African vertical datum at the four tide gauge benchmarks in a manner that is consistent to the international height reference system.

• Language: English
• Keywords: geoid, kvazigeoid, težnostni potencial, višinski datum, moteči potencial, anomalija višine, geoid, quasigeoid, geopotential, vertical datum, disturbing potential, height anomaly
• Work type: Scientific work
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Article acceptance date: 24.02.2021
• Publication date: 28.04.2021
• Year: 2021
• Number of pages: Str. 282-297
• Numbering: Letn. 65, št. 2
• PID: 20.500.12556/RUL-132744
• UDC: 528.242
• ISSN on article: 0351-0271
• DOI: 10.15292/geodetski-vestnik.2021.02.282-297
• COBISS.SI-ID: 70809347
• Publication date in RUL: 02.11.2021

Record is a part of a journal

• Title: Geodetski vestnik : glasilo Zveze geodetov Slovenije
• Shortened title: Geod. vestn.
• Publisher: Zveza geodetov Slovenije
• ISSN: 0351-0271
• COBISS.SI-ID: 5091842

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 28.04.2021

Secondary language

• Language: Slovenian
• Title: Ocena razlik med višinskim datumom južne afrike in datumom mednarodnega višinskega referenčnega sistema

Abstract

Razlika in vrednost težnostnega potenciala v Južni Afriki se ocenjujeta na štirih temeljnih referenčnih točkah, in sicer s primerjavo z mednarodnim višinskim referenčnim sistemom IHRS. Predvideva se, da obstajajo razlike med višinskim datumom Južne Afrike (WP) in globalnim višinskim datumom (W0 ). V raziskavi je bil uporabljen pristop rešitve problema geodetskega robnega pogoja za eno točko (angl. geodetic boundary value problem - GBVP), kjer smo z Brunsovo enačbo ocenili vrednost anomalije višine po teoriji Molodenskega iz tako imenovanega motečega potenciala (TP ). Na obravnavanih mareografih v Južni Afriki je težnostni potencial odstopal od globalnih referenčnih vrednostih za naslednje vrednosti: Cape Town 0,589 m2 s -2, Port Elizabeth-1,993 m2 s -2, East London -2,593 m2 s -2, Durban2,154 m2 s -2. Odmik višinskega datuma na obravnavanih točkah glede na mednarodni višinski referenčni sistem je tako 6,013 cenitmetra v Cape Townu, -20,347 cenitmetra v Port Elisabethu, -26,478 cenitmetra v East Londonu in 21,996 cenitmetra v Durbanu. Ugotovljene razlike se lahko uporabljajo za uskladitev višinskega datuma Južne Afrike z mednarodnim višinskim referenčnim sistemom.

• Keywords: geoid, kvazigeoid, težnostni potencial, višinski datum, moteči potencial, anomalija višine

Projects

• Funder: Other - Other funder or multiple funders
• Name: Postgraduate scholarship