Everything about Geoid
Ocean shape without winds and tides
The geoid is the shape Earth would have if covered by an ocean responding to the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent. This surface is extended through the continents. According to Carl Friedrich Gauss, who first described it, it is the "mathematical figure of the Earth", a smooth but irregular surface whose shape results from the uneven distribution of mass within and on the surface of Earth. It can be known only through extensive gravitational measurements and calculations. Despite being an important concept for almost 200 years in the history of geodesy and geophysics, it was not defined with any degree of precision until the advent of satellite geodesy in the mid-20th century. Mathematician Gladys West was the first person to synthesize a high-fidelity geoid from this satellite data. The geoid is one of the essential components of satellite-based global positioning systems. Wikipedia →
🧭 Start here: a 6-step reading path
- Read the overview: GeoidA 5-minute orientation
- Skim a recent paper: Impacts of Using the Rigorous Topographic Gravity Modeling Method and Lateral Density Variation Model on Topographic Reductions and Geoid Modeling: A Case Study in Colorado, USAInfluential work since 2022
- Pick up a classic book: Artifacts introduced in the point evaluation of functions expanded into a degree 360 spherical harmonic seriesThe most-reprinted book on the subject
- Read the landmark paper: Lower mantle heterogeneity, dynamic topography and the geoidCited 758 times
- Go sideways: Physical geodesyA closely related topic
- Go sideways: Orthometric heightA closely related topic
📖 Definitions
Noun The shape, extending through landmasses (continents, etc.), that the surface of the oceans of the Earth would take under the influence of the Earth's gravity and rotation alone, disregarding other factors such as winds and tides; that is, a surface of constant gravitational potential at zero elevation.
🏆 Landmark papers (most cited)
Lower mantle heterogeneity, dynamic topography and the geoid
Subducted slabs and the geoid: Constraints on mantle rheology and flow
Geoid anomalies in a dynamic Earth
PSGRN/PSCMP—a new code for calculating co- and post-seismic deformation, geoid and gravity changes based on the viscoelastic-gravitational dislocation theory
Long-wavelength variations in Earth’s geoid: physical models and dynamical implications
On postglacial geoid subsidence over the equatorial oceans
Hotspots, polar wander, Mesozoic convection and the geoid
A mean dynamic topography computed over the world ocean from altimetry, in situ measurements, and a geoid model
🆕 Influential since 2022
Impacts of Using the Rigorous Topographic Gravity Modeling Method and Lateral Density Variation Model on Topographic Reductions and Geoid Modeling: A Case Study in Colorado, USA
NW Pacific‐Panthalassa Intra‐Oceanic Subduction During Mesozoic Times From Mantle Convection and Geoid Models
Geoid Reveals the Density Structure of Cratonic Lithosphere
Hybrid geoid model over peninsular Malaysia (PMHG2020) using two approaches
A precise geoid model of Bosnia and Herzegovina by the KTH method and its validation
📚 Books worth reading
- 📕Artifacts introduced in the point evaluation of functions expanded into a degree 360 spherical harmonic seriesRichard H. Rapp · 1999
- 📕Altimetry data and the elastic stress tensor of subduction zonesMichele Caputo · 1985
- 📕The delineation and interpretation of the earth's gravity fieldBruce D. Marsh · 1983
- 📕Geoid undulation computations at laser tracking stationsVasilios K. Despotakis · 1987
- 📕The GeoidsGeoffrey E. Baddeley · 1980
- 📕The GeoidsGeoffrey E. Baddeley · 1980
- 📕Mantle convection and the state of the Earth's interiorBradford H. Hager · 1987
- 📕Mantle dynamics and geodesyArden Leroy Albee · 1990
Ranked by number of editions on Open Library, a rough measure of how lasting a book is.
🔗 Related topics
- Physical geodesy Physical geodesy is the study of the physical properties of Earth's gravity and its potential field (the geopotential), with a view to their application…
- Orthometric height The orthometric height (symbol H) is the vertical distance along the plumb line from a point of interest to a reference surface known as the geoid, the…
- Geodesy Geodesy (/dʒiːˈɒdɪsi/, jee-OD-iss-ee) or geodetics is the science of measuring and representing the geometry, gravity, and spatial orientation of Earth…
- Geopotential Geopotential (symbol W) is the potential of the Earth's gravity field. It has SI units of square metre per square seconds (m2/s2). For convenience it is…
- Satellite geodesy Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface…
- Earth Gravitational Model The Earth Gravitational Models (EGM) are a series of geopotential models of the Earth published by the National Geospatial-Intelligence Agency (NGA). They…
- Normal height Normal heights (symbol H ∗ {\displaystyle H^{*}} or H N {\displaystyle H^{N}} ; SI unit metre, m) is a type of height above sea level introduced by the…
- Figure of the Earth In geodesy, the figure of the Earth is the size and shape used to model planet Earth. The kind of figure depends on application, including the precision…