Geoid undulation modelling and interpretation at Ladak, NW Himalaya using GPS and levelling data

Banerjee, Paramesh; Foulger, G. R.; Satyaprakash,; Dabral, Chandra P.

doi:10.1007/s001900050221

Cited by 14 publications

(4 citation statements)

References 31 publications

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“…The topography corrected geoid undulation in the Himalaya is small, but still significant, compared to other mountainous regions (Banerjee et al, 1999). The geoid anomaly over the Himalaya-Tibet region suggests the existence of a deeper density distribution plausibly caused by the subducted high-density Tethys oceanic slab beneath the region (Jiménez-Munt et al, 2008).…”

Section: Geoid Anomalymentioning

confidence: 85%

Gravity Anomalies, Isostasy and Density Structure of the Indian Continental Lithosphere

2020

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Gravity anomalies across the Indian region depict most of the geological and tectonic domains of the Indian continental lithosphere, which evolved through Archean cratonic nucleation, Proterozoic accretion, Phanerozoic India-Eurasia plate convergence, and modification through many thermal perturbations and rifting. Integrated analysis of gravity and geoid anomalies together with topographic and heat flow data led to deciphering the mechanism of isostatic compensation of topographic and geological loads, lithospheric structure, and composition. This study discusses the nature of gravity (free-air, Bouguer and Isostatic) and geoid anomalies in relation to the topography, geology, and tectonics, and presents a lithospheric density model across the peninsular India and Himalaya. Southern peninsular Indian region shows relatively low Bouguer gravity anomalies compared to the northern region. The mobile belts are generally observed to have relatively higher Bouguer gravity anomalies, e.g., Eastern Ghats Mobile Belt compared to the shield regions. The gravity lows are observed over topographic features like the Western Ghats and Himalaya, while some of the topographic highs like Aravalli show positive gravity anomaly. The Indian Ocean Geoid Low varies from -82 m over Dharwar Craton to -98 m over the Southern Granulite Terrain and finally reaches a significant low of -106 m in the Indian Ocean. Flexural isostatic compensation with variable Effective Elastic Thickness (EET) ~10 km to 50 km prevails over the stable continental region. The lithospheric thickness varies from 80 km along the coastal region to 120-130 km beneath the Saurashtra Plateau, the Southern Granulite Terrain, and the Eastern Indian Shield, and reaches to more than 200 km under the Himalayan orogenic belt in the north. From Dharwar Craton to Bundelkhand Craton in central India, the lithospheric thickness varies between 160 and 180 km.

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Section: Geoid Anomalymentioning

confidence: 85%

Gravity Anomalies, Isostasy and Density Structure of the Indian Continental Lithosphere

2020

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“…1). The (known) ellipsoidal and orthometric heights are utilized to compute the geoid heights (Banarjee et al, 1999). Eq.…”

Section: Gnss/levellingmentioning

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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“…1). Geoid heights have been computed based on the known ellipsoidal and orthometric heights (Banarjee et al, 1999). Eq.…”

Section: Gnss/levellingmentioning

confidence: 99%

Evaluation of Recent Global Geopotential Models by GNSS/Levelling Data: Internal Aegean Region

Yılmaz

Turgut

Güllü

et al. 2016

International Journal of Engineering and Geosciences

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Global geopotential models of spherical harmonic coefficients are used to determine the external gravitational field of the Earth. These coefficients are derived from satellite orbit perturbations, terrestrial gravity anomalies and altimeter data. Hundreds of thousands of coefficients and standard deviation values for these coefficients are estimated from millions of observation. Measurement amount, homogenous distribution of the measurements of global scale, different measurement types reflecting the different frequencies of the gravity signal and measuringassessment techniques affect the model accuracy directly. Starting from 1960's and lasts to the present day and also gaining new acceleration with the satellite gravity field missions, every outcome of the studies related to the determination of the global Geopotential model is experienced by a series of validation tests. Accuracy of the model can either be determined from the estimated error degree variances concerning the coefficients (interior validation) or comparison of geoid heights, gravity anomalies, gravity disturbances and components of vertical deflection calculated from the model with terrestrial measurements directly (outer validation). In this paper, recent global geopotential models are primarily explained. Global geopotential models are compared with GNSS/levelling data of the study area. The objective of this comparison is to determine the best fit global geopotential model which will contribute to the study of Turkish geoid determination.

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Geoid undulation modelling and interpretation at Ladak, NW Himalaya using GPS and levelling data

Cited by 14 publications

References 31 publications

Gravity Anomalies, Isostasy and Density Structure of the Indian Continental Lithosphere

Gravity Anomalies, Isostasy and Density Structure of the Indian Continental Lithosphere

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

Evaluation of Recent Global Geopotential Models by GNSS/Levelling Data: Internal Aegean Region

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