Residual terrain modelling (RTM) in terms of the cap-modified spectral technique: RTM from a new perspective

Bucha, Blažej; Hirt, Christian; Yang, Meng; Kühn, Michael

doi:10.1007/s00190-019-01303-4

Cited by 8 publications

(3 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[44,50,69], etc., have demonstrated the effectiveness of RTM combined with GGM for achieving ultra-highresolution gravity fields globally and regionally, significantly enhancing the performance of GGMs. Additionally, various studies [44,52,70] have shown that this combined approach can recover approximately ∼90% of gravity signals over rugged areas, making it a valuable tool in areas lacking terrestrial gravity measurements. However, as shown in Table 1, over areas with large density anomalies, the classical RTM has limited effectiveness.…”

Section: The Limitations Of Classical Rtm Technique Over Areas With L...mentioning

confidence: 99%

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Yang,

Li,

Feng

et al. 2023

Remote Sensing

Self Cite

View full text Add to dashboard Cite

To calibrate airborne gravity gradiometers currently in development in China, it is urgent to build an airborne gravity gradiometer test site. The site’s selection depends on the preknowledge of high-resolution gravity and gradient structures. The residual terrain modelling (RTM) technique is generally applied to recover the short-scale gravity field signals. However, due to limitations in the quality and resolution of density models, RTM terrain generally assumes a constant density. This assumption can introduce significant errors in areas with substantial density anomalies and of reggued terrain, such as volcano areas. In this study, we promote a method to determine a high-resolution gravity field by integrating long-wavelength signals generated by EGM2008 with short-wavelength signals from terrain relief and shallow density anomalies. These short wavelength signals are recovered using the RTM technique with both constant density and density anomalies obtained through the equivalent source layer (ESL) method, utilizing sparse terrestrial gravity measurements. Compared to the recovery rate of 54.62% using the classical RTM method, the recovery rate increases to 86.22% after involving density anomalies. With this method, we investigate the gravity field signals over the Wudalianchi Volcano Field (WVF) both on the Earth’s surface and at a flight height of 100 m above the terrain. The contribution of each part and their attenuation characters are studied. In particular, the 5 km × 5 km area surrounding Bijiashan (BJS) and Wohushan (WHS) volcanos shows a strong gravity signature, making it a good candidate for the test site location. This study gives the location of the airborne gravity gradiometer test site which is an essential step in the instruments’ development. Furthermore, the method presented in this study offers a foundational framework for future data processing within the test site.

show abstract

Section: The Limitations Of Classical Rtm Technique Over Areas With L...mentioning

confidence: 99%

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Yang,

Li,

Feng

et al. 2023

Remote Sensing

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the latter case, harmonic correction is added in order to obtain a harmonically downward continued value. Various harmonic correction approaches have been studied in the past decades [3,19,20,32,33,36,[40][41][42]. In this study, we follow the classical approach of [19,20], in which the harmonic correction is computed based on the concept of mass condensation and is only applied to gravity.…”

Section: Rtm Corrections To Gravity Anomalies and Height Anomaliesmentioning

confidence: 99%

“…The SH approach first estimates the SH coefficients of the detailed topography via the surface SH analysis and then computes the heights of the reference topography via the SH synthesis. For more details about this approach, we refer to [32,33]. It should be noted that the RTM method utilizing the reference topography obtained from the SH approach has been successfully used for high-frequency GGM augmentation in many areas with different topographic regimes [26,28,[33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Experiences with the RTM Method in Local Quasi-Geoid Modeling

2023

Self Cite

View full text Add to dashboard Cite

In local quasi-geoid modeling, the residual terrain modeling (RTM) method is often used to remove short-wavelength gravity field signals from the measured gravity on the ground in order to obtain a regularized and smooth gravity field that is suited for field interpolation and modeling. Accurate computation of RTM corrections plays a crucial role in computing an accurate local quasi-geoid, and it requires a set of fine-tuned parameters, including the combination of DEMs with different resolutions for suitably representing the real topography, the choice of integration radius for properly defining the extent of the computation zone, and the determination of reference topography to properly describe the RTM-reduced Earth’s surface. To our knowledge, this has not been systematically documented, despite its obvious importance. This study aims to systematically investigate the impact of these factors on RTM correction computation and, consequently, on local quasi-geoid modeling to provide practical guidelines for real-world applications. The tesseroid-based gravity forward modeling technique is employed to investigate the following issues existing in the practical use of the RTM method: ① Can the combination of a high-resolution DEM and a DEM with a lower resolution replace the single use of the high-resolution DEM for RTM correction computation while maintaining accuracy and improving efficiency? If it does, how do I properly choose the resolution of this coarse DEM as well as the integration radius r1 for the inner zone and r2 for the outer zone? ② How large would the differences between the RTM corrections computed by three types of reference topographies, which are obtained from the direct averaging (DA) approach, the moving averaging (MA) approach, and the spherical harmonic (SH) approach, be, and how large would their impact on quasi-geoid modeling be? To obtain objective findings, two research regions were selected for this investigation. One is the Colorado test area (USA) with rugged terrain, and the other is the Auvergne test area (France) with moderate terrain. The main numerical findings are: (1) the combination of the 3” resolution DEM (inner zone) and the 30″ resolution DEM (outer zone) is sufficient for accurate and efficient RTM correction computation; (2) if the resolution of the reference topography is 5′ or slightly lower, all three types of reference topographies are able to obtain local quasi-geoid models at a similar accuracy level, while the values of r1 and r2 are preferred to be at least 20 km and 111 km, respectively; (3) if the reference topography has a resolution of 30′ or lower, the MA or SH reference topography is recommended, especially for the latter one, and the values of r1 and r2 are suggested to be at least 20 km and 222 km, respectively. The above numerical findings can be taken as a reference for local quasi-geoid determination in areas with different topographic regimes than the two selected test areas.

show abstract

Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu

Bucha

Sansò

2021

J Geod

View full text Add to dashboard Cite

Residual terrain modelling (RTM) in terms of the cap-modified spectral technique: RTM from a new perspective

Cited by 8 publications

References 46 publications

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Experiences with the RTM Method in Local Quasi-Geoid Modeling

Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu

Contact Info

Product

Resources

About