scholarly journals Improved Geoid Determination Based on the Shallow-Layer Method: A Case Study Using EGM08 and CRUST2.0 in the Xinjiang and Tibetan Regions

2013 ◽  
Vol 24 (4-1) ◽  
pp. 591 ◽  
Author(s):  
WenBin Shen ◽  
Jiancheng Han
Keyword(s):  
Geoid Determination ◽  
Layer Method ◽  
Shallow Layer

scholarly journals Determination of the height of Mount Everest using the shallow layer method

2021 ◽  
Author(s):  
Youchao Xie ◽  
Wenbin Shen ◽  
Jiancheng Han ◽  
Xiaole Deng
Keyword(s):  
Mount Everest ◽  
Layer Method ◽  
Shallow Layer

Comparison among Gravimetric, Astrogravimetric and Astrogeodetic Geoids: Case Study for Austria

2021 ◽  
Author(s):  
Hussein Abd-Elmotaal ◽  
Norbert Kühtreiber
Keyword(s):  
Gravity Anomalies ◽  
Geoid Determination ◽  
Data Sets ◽  
Deflections Of The Vertical ◽  
Collocation Technique ◽  
Dense Grid ◽  
Vening Meinesz ◽  
Stokes Integral ◽  
Stokes Kernel

<p>It is used to state that all geoid determination techniques should yield to the same geoid if the indirect effect is properly taken into account (Heiskanen and Moritz, 1967). The current study compares different geoid determination techniques for Austria. The used techniques are the gravimetric, astrogravimetric and astrogeodetic geoid determination techniques. The available data sets (gravity, deflections of the vertical, height, GPS) are described. The window remove-restore technique (Abd-Elmotaal and Kuehtreiber, 2003) has been used. The available gravity anomalies and the deflections of the vertical have been topographically-isostatically reduced using the Airy isostatic hypothesis. The reduced deflections have been used to interpolate deflections on a relatively dense grid covering the data window. These gridded reduced deflections have been used to compute an astrogeodetic geoid for Austria using least-squares collocation technique within the remove-restore scheme. The Vening Meinesz formula has been used to compute an astrogravimetric geoid for Austria. Another gravimetric geoid for Austria has been determined in the framework of the window remove-restore technique using Stokes integral with modified Stokes kernel. All computed geoids have been validated using GNSS/levelling derived geoid. A wide comparison among the derived geoids computed within the current investigation has been carried out.</p>

Effect of great lakes on gravity reduction and geoid determination caused by unclassified DTMs: case study for Lake Victoria, Africa

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Hussein A. Abd-Elmotaal ◽  
Kurt Seitz ◽  
Mostafa Ashry ◽  
Bernhard Heck
Keyword(s):  
Great Lakes ◽  
Lake Victoria ◽  
Geoid Determination

An alternative geoid model for Africa using the shallow-layer method

2021 ◽  
Author(s):  
Mostafa Ashry ◽  
Wen-Bin Shen ◽  
Hussein A. Abd-Elmotaal
Keyword(s):  
Geoid Model ◽  
Layer Method ◽  
Shallow Layer

scholarly journals The geoid of China and its surrounding areas determined by shallow layer method

2021 ◽  
Vol 32 (5.2) ◽  
Author(s):  
Youchao Xie ◽  
Wen-Bin Shen ◽  
Jiancheng Han ◽  
Jiancheng Li
Keyword(s):  
Layer Method ◽  
Shallow Layer ◽  
Surrounding Areas

Development of a global geoid model 2020 (GGM2020)

2020 ◽  
Author(s):  
WenBin Shen ◽  
Youchao Xie ◽  
Jiancheng Han ◽  
Jiancheng Li
Keyword(s):  
Gravity Field ◽  
Density Model ◽  
Layer Model ◽  
Geoid Model ◽  
Gravity Field Model ◽  
Layer Method ◽  
Shallow Layer ◽  
Inner Surface ◽  
Gps Leveling ◽  
Better Than

<p>We present an updated 5′ ×5′ global geoid model 2020 (GGM2020), which is determined based on the shallow layer method (or simply Shen method). We choose an inner surface S below the EGM2008 global geoid by 15 m, and the layer bounded by the inner surface S and the Earths geographical surface E is referred to as the shallow layer. We formulate the 3D shallow mass layer model using the refined 5′ ×5′ crust density model, CRUST1.0-5min, which is an improved 5′ ×5′ density model of the CRUST1.0 with taking into account the corrections of the areas covered by ice sheets and the land-ocean crossing regions. Based on the shallow mass layer model and the gravity field EGM2008 that is defined in the region outside the Earth’s geographical surface E, we determine the gravity field model EGM2008S that is defined in the whole region outside the inner surface S. Based on the gravity field EGM2008S and the geoid equation W(P) =W0, where W0 is the geopotential constant on the geoid and P is the point on the geoid G, we established a 5′ ×5′ global geoid model GGM2020. Comparisons show that in average the GGM2020 fits the globally available GPS/leveling points better than the EGM2008 global geoid. This study is supported by NSFCs (grant Nos. 41721003, 41631072, 41874023, 41804012, 41429401, 41574007).</p>

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