scholarly journals The geoid or quasigeoid – which reference surface should be preferred for a national height system?

2013 ◽  
Vol 3 (2) ◽  
pp. 103-109 ◽  
Author(s):  
L. E. Sjöberg
Keyword(s):  
Density Distribution ◽  
Analytical Continuation ◽  
Reference Surface ◽  
Numerical Instability ◽  
Convergence Problem ◽  
The World ◽  
Height System ◽  
Normal Heights ◽  
Integration Problem ◽  
Stokes Formula

Abstract Most European states use M. S. Molodensky’s concept of normal heights for their height systems with a quasigeoid model as the reference surface, while the rest of the world rely on orthometric heights with the geoid as the zero-level. Considering the advances in data caption and theory for geoid and quasigeoid determinations, the question is which system is the best choice for the future. It is reasonable to assume that the latter concept, in contrast to the former, will always suffer from some uncertainty in the topographic density distribution, while Molodensky’s approach to quasigeoid determination has a convergence problem. On the contrary, geoid and quasigeoid models computed by analytical continuation (e.g., rcr technique or KTH method) have no integration problem, and the quasigeoid can always be determined at least as accurate as the geoid. As the numerical instability of the analytical continuation is better controlled in the KTH method vs. the rcr method, we propose that any future height system be based on normal heights with a quasigeoid model computed similar to or directly based on the KTH method (Least squares modification of Stokes formula with additive corrections).

scholarly journals Interpolation Grid for Local Area of Iasi City

2014 ◽  
Vol 8 (1) ◽  
pp. 157-164
Author(s):  
Raluca Maria Mihalache ◽  
Andreea Manescu
Keyword(s):  
Unitary Transformation ◽  
National Level ◽  
Local Area ◽  
Sufficient Accuracy ◽  
Reference Surface ◽  
National Agency ◽  
Land Registration ◽  
Height System ◽  
Normal Heights ◽  
Interpolation Grid

Abstract Definitive transition to GNSS technology of achieving geodetic networks for cadastre implementation in cities and municipalities, enforce establishing a unique way of linking between current measurements and existing geodetic data, with a sufficient accuracy proper to urban cadastre standards. Regarding city of Iasi, is presented a different method of transformation which consist in an interpolation grid for heights system. The Romanian national height system is „Black Sea-1975” normal heights system. Founded in 1945 by Molodenski, this system uses the quasigeoid as reference surface, being in relation with the ellipsoid through the height anomalies sizes in each point. The unitary transformation between the ETRS- 89 ellipsoidal height system and the normal one, at national level is provided through the „TransdatRo” program developed by NACLR (National Agency for Cadastre and Land Registration).

Beyond Smart Grid: Alternatives for Transmission and Low-Cost Firming Storage of Stranded Renewables as Hydrogen and Ammonia Fuels via Underground Pipelines

2011 ◽  
Author(s):  
William C. Leighty ◽  
John H. Holbrook
Keyword(s):  
Smart Grid ◽  
Low Cost ◽  
Large Solution ◽  
Electricity Grid ◽  
Underground Pipelines ◽  
The World ◽  
Integration Problem ◽  
Salt Caverns ◽  
Annual Scale ◽  
Very High

We must soon “run the world on renewables” but cannot, and should not try to, accomplish this entirely with electricity transmission. We need to supply all energy, not just electricity, from diverse renewable energy (RE) resources, both distributed and centralized, where the world’s richest RE resources — of large geographic extent and high intensity — are stranded: far from end-users with inadequate or nonexistent gathering and transmission systems to deliver the energy. Electricity energy storage cannot affordably firm large, intermittent renewables at annual scale, while carbon-free gaseous hydrogen (GH2) and liquid anhydrous ammonia (NH3) fuels can: GH2 in large solution-mined salt caverns, NH3 in surface tanks, both pressurized and refrigerated. “Smart Grid” is emerging as primarily a DSM (demand side management) strategy to encourage energy conservation. Making the electricity grid “smarter” does not: 1. Increase physical transmission capacity; 2. Provide affordable annual-scale firming storage for RE; 3. Solve grid integration problem for large, time-varying RE; 4. Alleviate NIMBY objections to new transmission siting; 5. Reduce the high O&M costs of overhead electric lines. The “smarter” grid may be more vulnerable to cyberattack. Adding storage, control, and quality adjunct devices to the electricity grid, to accommodate very high renewables content, may be technically and economically inferior to GH2 and NH3 RE systems. Thus, we need to look beyond “smart grid”, expanding our concept of “transmission”, to synergistically and simultaneously solve the transmission, firming storage, and RE integration “balancing” problems now severely constraining our progress toward “running the world on renewables”.

scholarly journals Policy integration, problem-solving, and the coronavirus disease crisis: lessons for policy design

2022 ◽  
Author(s):  
Martino Maggetti ◽  
Philipp Trein
Keyword(s):  
Problem Solving ◽  
Policy Design ◽  
Policy Instruments ◽  
Policy Integration ◽  
Catching Up ◽  
The World ◽  
Integration Problem ◽  
The One ◽  
Integrated Response ◽  
Crisis Responses

Abstract The coronavirus disease pandemic has exposed differences in the capacity of governments around the world to integrate and coordinate different policy instruments into a coherent response. In this article, we conceptualize and empirically examine policy integration in responses to the coronavirus disease crisis in 35 countries. We then discuss how the interplay between restrictions, health protection, and economic policy has been articulated between, on the one hand, a policy design based on the complementarity of pro-public health and pro-economy measures, implying an integrated response, and, on the other, a policy design based on the perception of an inherent trade-off between the two. Finally, we discuss three implications from our analysis of policy integration against the coronavirus disease crisis for the post-COVID state: (a) the normalization and adaptation of integrated crisis responses; (b) the possible acceleration and “catching up” of problem-solving capacity as governments may use the crisis as an instance to put into place new social policies; and (c) policy integration as an accelerator of policy complexity and resistance against technocracy in the post-COVID state.

Running the World on Renewables: Alternatives for Transmission and Low-Cost Firming Storage of Stranded Renewables as Hydrogen and Ammonia Fuels via Underground Pipelines

2012 ◽  
Author(s):  
William C. Leighty ◽  
John H. Holbrook
Keyword(s):  
Smart Grid ◽  
Low Cost ◽  
Large Solution ◽  
Electricity Grid ◽  
Underground Pipelines ◽  
The World ◽  
Integration Problem ◽  
Salt Caverns ◽  
Annual Scale ◽  
Very High

We must soon “run the world on renewables” but cannot, and should not try to, accomplish this entirely with electricity transmission. We need to supply all energy, not just electricity, from diverse renewable energy (RE) resources, both distributed and centralized, where the world’s richest RE resources — of large geographic extent and high intensity — are stranded: far from end-users with inadequate or nonexistent gathering and transmission systems to deliver the energy. Electricity energy storage cannot affordably firm large, intermittent renewables at annual scale, while carbon-free gaseous hydrogen (GH2) and liquid anhydrous ammonia (NH3) fuels can: GH2 in large solution-mined salt caverns, NH3 in surface tanks, both pressurized and refrigerated. “Smart Grid” is emerging as primarily a DSM (demand side management) strategy to encourage energy conservation. Making the electricity grid “smarter” does not: 1. Increase physical transmission capacity; 2. Provide affordable annual-scale firming storage for RE; 3. Solve grid integration problem for large, time-varying RE; 4. Alleviate NIMBY objections to new transmission siting; 5. Reduce the high O&M costs of overhead electric lines. The “smarter” grid may be more vulnerable to cyberattack. Adding storage, control, and quality adjunct devices to the electricity grid, to accommodate very high renewables content, may be technically and economically inferior to GH2 and NH3 RE systems. Thus, we need to look beyond “smart grid”, expanding our concept of “transmission”, to synergistically and simultaneously solve the transmission, firming storage, and RE integration “balancing” problems now severely constraining our progress toward “running the world on renewables”.

scholarly journals DFHRS-BASED COMPUTATION OF QUASI-GEOID OF LATVIA

2013 ◽  
Vol 39 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Viktoras Lukoševičius
Keyword(s):  
Quality Control ◽  
Civil Engineering ◽  
Geoid Height ◽  
High Accuracy ◽  
Reference Surface ◽  
Geoid Model ◽  
Coordinate Determination ◽  
Role Transformation ◽  
Normal Heights

In geodesy, civil engineering and related fields high accuracy coordinate determination is needed, for that reason GNSS technologies plays important role. Transformation from GNSS derived ellipsoidal heights to orthometric or normal heights requires a high accuracy geoid or quasi-geoid model, respectively the accuracy of the currently used Latvian gravimetric quasi-geoid model LV'98 is 6–8 cm. The objective of this work was to calculate an improved quasi-geoid (QGeoid) for Latvia. The computation was performed by applying the DFHRS software. This paper discusses obtained geoid height reference surface, its comparisons to other geoid models, fitting point statistics and quality control based on independent measurements.

scholarly journals The topographic bias in Stokes’ formula vs. the error of analytical continuation by an Earth Gravitational Model - are they the same?

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
L. E. Sjöberg
Keyword(s):  
Gravity Anomaly ◽  
Spherical Harmonics ◽  
Analytical Continuation ◽  
Geoid Determination ◽  
Disturbing Potential ◽  
Solid Spherical Harmonics ◽  
Topographic Bias ◽  
Gravitational Model ◽  
Stokes Formula ◽  
Original Formula

AbstractGeoid determination below the topographic surface in continental areas using analytical continuation of gravity anomaly and/or an external type of solid spherical harmonics determined by an Earth GravitationalModel (EGM) inevitably leads to a topographic bias, as the true disturbing potential at the geoid is not harmonic in contrast to its estimates. We show that this bias differs for the geoid heights represented by Stokes’ formula, an EGMand for the modified Stokes formula. The differences are due to the fact that the EGM suffers from truncation and divergence errors in addition to the topographic bias in Stokes’ original formula.

scholarly journals A numerical test of the topographic bias

2018 ◽  
Vol 8 (1) ◽  
pp. 14-17 ◽  
Author(s):  
L.E. Sjöberg ◽  
M.S.S. Joud
Keyword(s):  
Density Distribution ◽  
Simple Formula ◽  
Numerical Test ◽  
Physical Geodesy ◽  
Gravity Anomalies ◽  
Analytical Continuation ◽  
External Potential ◽  
The Earth ◽  
Topographic Bias ◽  
The Common

Abstract In 1962 A. Bjerhammar introduced the method of analytical continuation in physical geodesy, implying that surface gravity anomalies are downward continued into the topographic masses down to an internal sphere (the Bjerhammar sphere). The method also includes analytical upward continuation of the potential to the surface of the Earth to obtain the quasigeoid. One can show that also the common remove-compute-restore technique for geoid determination includes an analytical continuation as long as the complete density distribution of the topography is not known. The analytical continuation implies that the downward continued gravity anomaly and/or potential are/is in error by the so-called topographic bias, which was postulated by a simple formula of L E Sjöberg in 2007. Here we will numerically test the postulated formula by comparing it with the bias obtained by analytical downward continuation of the external potential of a homogeneous ellipsoid to an inner sphere. The result shows that the postulated formula holds: At the equator of the ellipsoid, where the external potential is downward continued 21 km, the computed and postulated topographic biases agree to less than a millimetre (when the potential is scaled to the unit of metre).

scholarly journals On the geoid and orthometric height vs. quasigeoid and normal height

2018 ◽  
Vol 8 (1) ◽  
pp. 115-120
Author(s):  
Lars E. Sjöberg
Keyword(s):  
Density Distribution ◽  
Bouguer Anomaly ◽  
Equipotential Surface ◽  
Geoid Model ◽  
Normal Height ◽  
Numerical Resolution ◽  
Numerical Studies ◽  
Normal Heights ◽  
Orthometric Heights ◽  
The Difference

Abstract The geoid, but not the quasigeoid, is an equipotential surface in the Earth’s gravity field that can serve both as a geodetic datum and a reference surface in geophysics. It is also a natural zero-level surface, as it agrees with the undisturbed mean sea level. Orthometric heights are physical heights above the geoid,while normal heights are geometric heights (of the telluroid) above the reference ellipsoid. Normal heights and the quasigeoid can be determined without any information on the Earth’s topographic density distribution, which is not the case for orthometric heights and geoid. We show from various derivations that the difference between the geoid and the quasigeoid heights, being of the order of 5 m, can be expressed by the simple Bouguer gravity anomaly as the only term that includes the topographic density distribution. This implies that recent formulas, including the refined Bouguer anomaly and a difference between topographic gravity potentials, do not necessarily improve the result. Intuitively one may assume that the quasigeoid, closely related with the Earth’s surface, is rougher than the geoid. For numerical studies the topography is usually divided into blocks of mean elevations, excluding the problem with a non-star shaped Earth. In this case the smoothness of both types of geoid models are affected by the slope of the terrain,which shows that even at high resolutions with ultra-small blocks the geoid model is likely as rough as the quasigeoid model. In case of the real Earth there are areas where the quasigeoid, but not the geoid, is ambiguous, and this problem increases with the numerical resolution of the requested solution. These ambiguities affect also normal and orthometric heights. However, this problem can be solved by using the mean quasigeoid model defined by using average topographic heights at any requested resolution. An exact solution of the ambiguity for the normal height/quasigeoid can be provided by GNSS-levelling.

scholarly journals Quality determination of mean sea level heights with GNSS levelling on the Ljubljana city area

2021 ◽  
Vol 65 (02) ◽  
pp. 219-233
Author(s):  
Miran Kuhar ◽  
Robert Brglez ◽  
Božo Koler
Keyword(s):  
Sea Level ◽  
Reference Surface ◽  
Mean Sea Level ◽  
City Area ◽  
Height System ◽  
The City

This paper describes the quality determination of heights above mean sea level using RTK GNSS-levelling and new height reference surface SLO_VRP2016/Koper on the city area of Ljubljana. At 57 chosen benchmarks, quasigeoid heights were determined using ellipsoidal heights, determined with RTK GNNS-levelling technique and heights above mean sea level in the new height system SVS2010. The measured quasigeoid heights were compared with values interpolated from the new height reference surface SLO_VRP2016/Koper.

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