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Bouguer Anomaly
In geodesy and geophysics, the Bouguer anomaly (named after Pierre Bouguer) is a gravity anomaly, corrected for the height at which it is measured and the attraction of terrain. The height correction alone gives a free-air gravity anomaly. Definition The Bouguer anomaly g_B defined as: g_B = g_ - \delta g_B + \delta g_T Here, * g_F is the free-air gravity anomaly. * \delta g_B is the ''Bouguer correction'' which allows for the gravitational attraction of rocks between the measurement point and sea level; * \delta g_T is a ''terrain correction'' which allows for deviations of the surface from an infinite horizontal plane The free-air anomaly g_F, in its turn, is related to the observed gravity g_ as follows: g_F = g_ - g_\lambda + \delta g_F where: * g_\lambda is the correction for latitude (because the Earth is not a perfect sphere; see normal gravity); * \delta g_F is the free-air correction. Reduction A Bouguer reduction is called ''simple'' (or ''incomplete'') if the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesy
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as '' planetary geodesy''). Geodynamical phenomena, including crustal motion, tides and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques and relying on datums and coordinate systems. The job title is geodesist or geodetic surveyor. History Definition The word geodesy comes from the Ancient Greek word ''geodaisia'' (literally, "division of Earth"). It is primarily concerned with positioning within the temporally varying gravitational field. Geodesy in the German-speaking world is divided into "higher geodesy" ( or ), which is concerned with measuring Earth on the global scale, and "practical geodes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume: : \rho = \frac where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium and iridium are the densest known elements at standard conditions for temperature and pressure. To simplify comparisons of density across different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gal (unit)
The gal (symbol: Gal), sometimes called galileo after Galileo Galilei, is a unit of acceleration sometimes used in gravimetry. BIPM ''SI brochure'', 8th ed. 2006Table 9: Non-SI units associated with the CGS and the CGS-Gaussian system of units. The gal is defined as 1 centimeter per second squared (1 cm/s2). The milligal (mGal) and microgal (µGal) are respectively one thousandth and one millionth of a gal. The gal is not part of the International System of Units (known by its French-language initials "SI"). In 1978 the CIPM decided that it was permissible to use the gal "with the SI until the CIPM considers that tsuse is no longer necessary". However, use of the gal is deprecated by ISO 80000-3:2006. The gal is a derived unit, defined in terms of the centimeter–gram–second (CGS) base unit of length, the centimeter, and the second, which is the base unit of time in both the CGS and the modern SI system. In SI base units, 1 Gal is equal to 0.01 m/s2. The a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laguna Merín
Lagoon Mirim (Portuguese, ) or Merín (Spanish, ) is a large estuarine lagoon which extends from southern Rio Grande do Sul state in Brazil into eastern Uruguay. Lagoa Mirim is separated from the Atlantic Ocean by a sandy, partially barren isthmus. The Jaguarão/Yaguarón, Tacuarí and Cebollatí Rivers empty into Lagoon Mirim, while the São Gonçalo Channel connects it with Lagoa dos Patos to the north. Location Lagoon Mirim is about long by wide and in area. It is more irregular in outline than its larger neighbor to the north, Lagoa dos Patos, and discharges into the latter through São Gonçalo Channel, which is navigable by small boats. Lagoa Mirim has no direct connection to the Atlantic, but the Rio Grande, a tidal channel about long which connects Lagoon dos Patos to the Atlantic, affords an entrance to the navigable inland waters of both lagoons and several small ports. Both lagoons are the remains of an ancient depression in the coastline shut in by sand beach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering the Río de la Plata to the south and the Atlantic Ocean to the southeast. It is part of the Southern Cone region of South America. Uruguay covers an area of approximately and has a population of an estimated 3.4 million, of whom around 2 million live in the metropolitan area of its capital and largest city, Montevideo. The area that became Uruguay was first inhabited by groups of hunter–gatherers 13,000 years ago. The predominant tribe at the moment of the arrival of Europeans was the Charrúa people, when the Portuguese first established Colónia do Sacramento in 1680; Uruguay was colonized by Europeans late relative to neighboring countries. The Spanish founded Montevideo as a military stronghold in the early 18th century bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
