Regional gravimetric quasi-geoid model and transformation surface to national height system for Turkey (THG-09)

Kılıçoǧlu, Ali; Direnc, A.; Yıldız, Hasan; Bölme, Murat; Aktuğ, Bahadır; Simav, Mehmet; Lenk, Onur

doi:10.1007/s11200-010-9023-z

Cited by 21 publications

(12 citation statements)

References 16 publications

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“…see the data holdings of the Bureau Gravimétrique International, http://bgi.omp.obs-mip.fr/), and is a particular issue for regions where the geoid changes rapidly from land to ocean. The coastlines of the eastern Mediterranean, including the south coast of Turkey, provide such example regions (Kiliçoğlu et al 2011). …”

Section: Introductionmentioning

confidence: 99%

The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques

Woodworth

Gravelle

Marcos

et al. 2015

J Geod

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We review the measurement of the mean dynamic topography (MDT) of the Mediterranean using ellipsoidal heights of sea level at discrete tide gauge locations, and across the entire basin using satellite altimetry, subtracting estimates of the geoid obtained from recent models. This 'geodetic approach' to the determination of the MDT can be compared to the independent 'ocean approach' that involves the use of in situ oceanographic measurements and ocean modelling. We demonstrate that with modern geoid and ocean models there is an encouraging level of consistency between the two sets of MDTs. In addition, we show how important geodetic MDT information can be in judging between existing global ocean circulation models, and in providing insight for the development of new ones. The review makes clear the major limitations in Mediterranean data sets that prevent a more complete validation, including the need for improved geoid models of high spatial resolution and accuracy. Suggestions are made on how a greater amount of reliable geo-located tide gauge information can be obtained in the future. IntroductionThis paper discusses the mean dynamic topography (MDT) of the Mediterranean and its measurement by geodetic techniques. The MDT is the amount by which the Mean Sea Surface (MSS) is further from the centre of the Earth than a surface called the geoid, which is an equipotential surface resulting from the Earth's spatially-varying gravity field, and which would correspond to the MSS in the absence of an ocean circulation. An accurate measurement of the MDT can, therefore, provide oceanographers with insight into the circulation. Conversely, knowledge of the circulation, obtained by a number of oceanographic techniques can be used to infer the MDT. 2Much is already known about the mean circulation of the Mediterranean and its variability (e.g. Pinardi and Masetti 2000) and, therefore, also about the spatial variation of its MDT. This insight has largely been obtained using in situ oceanographic measurements and ocean modelling. However, in recent years major advances have been made in geodetic techniques that have enabled the MDT to be determined, for the first time, as the difference between MSS and geoid to the accuracy required for oceanographic research (e.g. Bingham et al. 2014). These techniques have primarily involved satellite altimetry to provide the MSS over the open ocean and space gravity to provide the geoid, complemented at the coast with the use of tide gauges equipped with Global Positioning System (GPS) equipment (Woodworth et al. 2012). By studying the Mediterranean, particular lessons can be learned in the use of these techniques, notably by pointing to missing infrastructure and data limitations, which can also be relevant to discussion of the MDT in other data-sparse regions around the world.Models of the MDT in the Mediterranean have already been made by previous authors in various ways (e.g. Rio et al. 2014a). Consequently, the present paper focuses on reviewing how an MDT model can be compa...

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Section: Introductionmentioning

confidence: 99%

The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques

Woodworth

Gravelle

Marcos

et al. 2015

J Geod

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“…(Pavlis et al, 2012). The national geoid model for Turkish territory, Turkish Hybrid Geoid 2009 (THG-09) (Kilicoglu et al, 2011) was computed depending on EGM2008.…”

Section: Earth Gravitational Model 2008mentioning

confidence: 99%

The Evaluation of High-Degree Geopotential Models for Regional Geoid Determination in Turkey

Yılmaz¹,

Turgut²,

Güllü³

et al. 2017

AKU-J. Sci. Eng.

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High-degree geopotential models of spherical harmonic coefficients are used for modelling the exterior gravity field of the Earth. These coefficients are derived from satellite tracking data, altimeter data, and terrestrial and airborne gravity data. Hundreds of thousands of coefficients and standard deviation values for these coefficients are estimated from millions of measurements. The geopotential model accuracy is affected by the amount, the distribution and the type of measurements. The satellite gravity field missions have provided accurate data forming geopotential models since 1960's. The geopotential models related to the satellite gravity field missions are experienced by interior validation (estimated error degree variances of fully-normalized coefficients) or outer validation (comparison of model based gravity anomalies and geoid heights with terrestrial measurements). In this paper, recent high-degree geopotential models are primarily explained and evaluated by GNSS/levelling data of a selected study area. The objective of this evaluation is to determine the high-degree geopotential model giving a better fit to the GNSS/levelling data over the study area for the contribution to the regional geoid determination studies in Turkey. Türkiye'de Bölgesel Jeoid Tespiti için Yüksek Dereceli Jeopotansiyel Modellerin Değerlendirilmesi Anahtar kelimelerJeoid; Jeopotansiyel model; GNSS/nivelman. ÖzetKüresel harmonik katsayılardan oluşan yüksek dereceli jeopotansiyel modeller Dünya'nın dış gravite alanının modellenmesi için kullanılır. Bu katsayılar uydu takip verisinden, altimetre verisinden ve yersel graviteden türetilir. Yüzbinlerce katsayı ve bu katsayıların standart sapma değerleri milyonlarca ölçümden hesaplanır. Jeopotansiyel modelin doğruluğu ölçümlerin miktarından, dağılımından ve türünden etkilenir. Uydu gravite görevleri, 1960 lardan beri jeopotansiyel modelleri oluşturan doğru veri sağlamaktadır. Uydu gravite görevleri ile bağlantılı jeopotansiyel modeller iç geçerlilik (tam normalleştirilmiş katsayıların hesaplanan hata derece varyansları) veya dış geçerlilik (model bazlı gravite anomalilerinin ve jeoid yüksekliklerinin yersel ölçüler ile karşılaştırılması) ile değerlendirilir. Bu çalışmada, güncel yüksek dereceli jeopotansiyel modeller öncelikli olarak açıklanmış ve seçilmiş bir çalışma alanında GNSS/nivelman verisi kullanılarak değelendirilmiştir. Bu değerlendirmenin amacı, Türkiye'deki bölgesel jeoid tespiti çalışmalarına katkıda bulunmak için, çalışma alanındaki GNSS/nivelman verisine daha iyi uyan yüksek dereceli jeopotansiyel modelin belirlenmesidir.

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“…In equation (1)are fully normalized associated Leg-endre functions. GM is geocentric gravitational con-stant, indicating the maximum degree(2190) of EI-GEN-6C4 spherical harmonic expansion, the coordi-nate tripler ) , , ( λ θ r denotes the geocentric polar coor-dinate of radius, geocentric co-latitude and longitude, which are computed from the geodetic coordinates that is geodetic latitude, geodetic longitude and geo-detic height, a are EIGEN-6C4 scaling parame-ters(semi major axis), γ is normal gravity on the surface of the reference ellipsoid.…”

Section: Computing Height Anomaly For Gravity Field Modelmentioning

confidence: 99%

Compensating method of the height anomalies for ultra-high Earth's gravity field model

Qingwu¹,

Qu²,

Li³

et al. 2017

Proceedings of the 2016 4th International Conference on Renewable Energy and Environmental Technology (ICREET 2016)

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An ultra-high order Earth's gravity field model,such as EIGEN-6C4 and EGM2008, the order and degree of its expansion are limited, there will be a certain truncation error. RTM residual height anomaly can by high-resolution SRTM data and DTM2006.0 data using prism integral method is calculated. The experiment results show that (1) RTM residual height anomaly before fitting makes all the standard deviation of the EIGEN-6C4 and EGM2008(2190 order) model to be increased by 5.7 mm, the contribution rate of the truncation error of 10% and 7% respectively (2) RTM residual height anomaly after fitting makes their standard deviation to be increased 1 cm and 3.3 cm respectively, the contribution rate of truncation error of the model were 2% and 6% respectively.(3) RTM height anomaly changes with the increase of integral radius, its value tends to be stable, converge to 2 cm, EIGEN-6C4 and EGM2008 model elevation changes within 110 km radius of integral and are within 105 km of centimeter level. (4) RTM technology is a kind of an effective compensation method for ultra-high order Earth's gravity field model accuracy, help to improve the accuracy of the quasigeoid.

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Regional gravimetric quasi-geoid model and transformation surface to national height system for Turkey (THG-09)

Cited by 21 publications

References 16 publications

The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques

The status of measurement of the Mediterranean mean dynamic topography by geodetic techniques

The Evaluation of High-Degree Geopotential Models for Regional Geoid Determination in Turkey

Compensating method of the height anomalies for ultra-high Earth's gravity field model

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