38-589: Landaff may refer to: Landaff, New Hampshire , a town in Grafton County Landaff Andrews (1803–1888), United States Representative from Kentucky Earl Landaff , a title in the Peerage of Ireland Francis Mathew, 1st Earl Landaff (1738–1806) Francis Mathew, 2nd Earl Landaff (1768–1833) See also [ edit ] All pages with titles containing Landaff Landulf ,
76-409: A defined barometric pressure . Generally, the pressure used to set the altimeter is the barometric pressure that would exist at MSL in the region being flown over. This pressure is referred to as either QNH or "altimeter" and is transmitted to the pilot by radio from air traffic control (ATC) or an automatic terminal information service (ATIS). Since the terrain elevation is also referenced to MSL,
114-432: A few metres, in timeframes ranging from minutes to months: Between 1901 and 2018, the average sea level rose by 15–25 cm (6–10 in), with an increase of 2.3 mm (0.091 in) per year since the 1970s. This was faster than the sea level had ever risen over at least the past 3,000 years. The rate accelerated to 4.62 mm (0.182 in)/yr for the decade 2013–2022. Climate change due to human activities
152-431: A household in the town was $ 41,964, and the median income for a family was $ 48,500. Males had a median income of $ 35,156 versus $ 23,438 for females. The per capita income for the town was $ 18,033. About 6.9% of families and 7.1% of the population were below the poverty line , including 5.7% of those under age 18 and 12.9% of those age 65 or over. Sea level Mean sea level ( MSL , often shortened to sea level )
190-603: A masculine given name Llandaff , a district, community and electoral ward in Cardiff, Wales, United Kingdom Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Landaff . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Landaff&oldid=1098098587 " Category : Disambiguation pages Hidden categories: Short description
228-438: A reference datum for mean sea level (MSL). It is also used in aviation, where some heights are recorded and reported with respect to mean sea level (contrast with flight level ), and in the atmospheric sciences , and in land surveying . An alternative is to base height measurements on a reference ellipsoid approximating the entire Earth, which is what systems such as GPS do. In aviation, the reference ellipsoid known as WGS84
266-470: A sharp reduction in greenhouse gas emissions, this may increase to hundreds of millions in the latter decades of the century. Local factors like tidal range or land subsidence will greatly affect the severity of impacts. For instance, sea level rise in the United States is likely to be two to three times greater than the global average by the end of the century. Yet, of the 20 countries with
304-417: Is an average surface level of one or more among Earth 's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datum – a standardised geodetic datum – that is used, for example, as a chart datum in cartography and marine navigation , or, in aviation, as the standard sea level at which atmospheric pressure
342-488: Is because the sea is in constant motion, affected by the tides, wind , atmospheric pressure, local gravitational differences, temperature, salinity , and so forth. The mean sea level at a particular location may be calculated over an extended time period and used as a datum . For example, hourly measurements may be averaged over a full Metonic 19-year lunar cycle to determine the mean sea level at an official tide gauge . Still-water level or still-water sea level (SWL)
380-518: Is different from Wikidata All article disambiguation pages All disambiguation pages Landaff, New Hampshire Landaff is a town in Grafton County , New Hampshire , United States. As of the 2020 census , the town population was 446. The name on the town charter is "Llandaff", after the Bishop of Llandaff , chaplain to England's King George III . Originally, however,
418-427: Is due to change in either the volume of water in the world's oceans or the volume of the oceanic basins . Two major mechanisms are currently causing eustatic sea level rise. First, shrinking land ice, such as mountain glaciers and polar ice sheets, is releasing water into the oceans. Second, as ocean temperatures rise, the warmer water expands. Many factors can produce short-term changes in sea level, typically within
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#1732766112751456-525: Is in the White Mountain National Forest , accessible via Cobble Hill Trail and Ore Hill Trail from the north. Natural features of Landaff include many viewsheds, mountain summits, wetlands, undeveloped woodland and farm land. The main bodies of water in town are Chandler Pond, Jericho Pond and Gordon Pond. Landaff is home to numerous species of wildlife. Black bear, moose, white-tail deer, beaver, eastern turkey, and coyote are among
494-483: Is increasingly used to define heights; however, differences up to 100 metres (328 feet) exist between this ellipsoid height and local mean sea level. Another alternative is to use a geoid -based vertical datum such as NAVD88 and the global EGM96 (part of WGS84). Details vary in different countries. When referring to geographic features such as mountains, on a topographic map variations in elevation are shown by contour lines . A mountain's highest point or summit
532-512: Is measured to calibrate altitude and, consequently, aircraft flight levels . A common and relatively straightforward mean sea-level standard is instead a long-term average of tide gauge readings at a particular reference location. Sea levels can be affected by many factors and are known to have varied greatly over geological time scales . Current sea level rise is mainly caused by human-induced climate change . When temperatures rise, mountain glaciers and polar ice sheets melt, increasing
570-450: Is the level of the sea with motions such as wind waves averaged out. Then MSL implies the SWL further averaged over a period of time such that changes due to, e.g., the tides , also have zero mean. Global MSL refers to a spatial average over the entire ocean area, typically using large sets of tide gauges and/or satellite measurements. One often measures the values of MSL with respect to
608-727: Is the main cause. Between 1993 and 2018, melting ice sheets and glaciers accounted for 44% of sea level rise , with another 42% resulting from thermal expansion of water . Sea level rise lags behind changes in the Earth 's temperature by many decades, and sea level rise will therefore continue to accelerate between now and 2050 in response to warming that has already happened. What happens after that depends on human greenhouse gas emissions . If there are very deep cuts in emissions, sea level rise would slow between 2050 and 2100. It could then reach by 2100 slightly over 30 cm (1 ft) from now and approximately 60 cm (2 ft) from
646-531: Is typically illustrated with the AMSL height in metres, feet or both. In unusual cases where a land location is below sea level, such as Death Valley, California , the elevation AMSL is negative. It is often necessary to compare the local height of the mean sea surface with a "level" reference surface, or geodetic datum, called the geoid . In the absence of external forces, the local mean sea level would coincide with this geoid surface, being an equipotential surface of
684-622: The geoid of the Earth, which approximates the local mean sea level for locations in the open ocean. The geoid includes a significant depression in the Indian Ocean , whose surface dips as much as 106 m (348 ft) below the global mean sea level (excluding minor effects such as tides and currents). Precise determination of a "mean sea level" is difficult because of the many factors that affect sea level. Instantaneous sea level varies substantially on several scales of time and space. This
722-418: The height above mean sea level (AMSL). The term APSL means above present sea level, comparing sea levels in the past with the level today. Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,949.903 mi) at the poles and 6,371.001 km (3,958.756 mi) on average. This flattened spheroid , combined with local gravity anomalies , defines
760-562: The 1690s. Satellite altimeters have been making precise measurements of sea level since the launch of TOPEX/Poseidon in 1992. A joint mission of NASA and CNES , TOPEX/Poseidon was followed by Jason-1 in 2001 and the Ocean Surface Topography Mission on the Jason-2 satellite in 2008. Height above mean sea level ( AMSL ) is the elevation (on the ground) or altitude (in the air) of an object, relative to
798-973: The 19th century. With high emissions it would instead accelerate further, and could rise by 1.0 m ( 3 + 1 ⁄ 3 ft) or even 1.6 m ( 5 + 1 ⁄ 3 ft) by 2100. In the long run, sea level rise would amount to 2–3 m (7–10 ft) over the next 2000 years if warming stays to its current 1.5 °C (2.7 °F) over the pre-industrial past. It would be 19–22 metres (62–72 ft) if warming peaks at 5 °C (9.0 °F). Rising seas affect every coastal and island population on Earth. This can be through flooding, higher storm surges , king tides , and tsunamis . There are many knock-on effects. They lead to loss of coastal ecosystems like mangroves . Crop yields may reduce because of increasing salt levels in irrigation water. Damage to ports disrupts sea trade. The sea level rise projected by 2050 will expose places currently inhabited by tens of millions of people to annual flooding. Without
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#1732766112751836-448: The Earth's gravitational field which, in itself, does not conform to a simple sphere or ellipsoid and exhibits gravity anomalies such as those measured by NASA's GRACE satellites . In reality, the geoid surface is not directly observed, even as a long-term average, due to ocean currents, air pressure variations, temperature and salinity variations, etc. The location-dependent but time-persistent separation between local mean sea level and
874-705: The Marégraphe in Marseilles measures continuously the sea level since 1883 and offers the longest collated data about the sea level. It is used for a part of continental Europe and the main part of Africa as the official sea level. Spain uses the reference to measure heights below or above sea level at Alicante , while the European Vertical Reference System is calibrated to the Amsterdam Peil elevation, which dates back to
912-456: The amount of water in the oceans, while the existing seawater also expands with heat. Because most of human settlement and infrastructure was built in response to a more-normalized sea level with limited expected change, populations affected by sea level rise will need to invest in climate adaptation to mitigate the worst effects or, when populations are at extreme risk, a process of managed retreat . The term above sea level generally refers to
950-534: The animals living in the thousands of open acres, as well as ruffed grouse and other upland birds. Outdoor recreational opportunities abound for hunting, fishing, cross-country skiing, snowshoeing, hiking, nature observation and snowmobiling. As of the census of 2000, there were 378 people, 154 households, and 107 families residing in the town. The population density was 13.3 inhabitants per square mile (5.1/km ). There were 214 housing units at an average density of 7.5 per square mile (2.9/km ). The racial makeup of
988-482: The geoid is referred to as (mean) ocean surface topography . It varies globally in a typical range of ±1 m (3 ft). Several terms are used to describe the changing relationships between sea level and dry land. The melting of glaciers at the end of ice ages results in isostatic post-glacial rebound , when land rises after the weight of ice is removed. Conversely, older volcanic islands experience relative sea level rise, due to isostatic subsidence from
1026-634: The greatest exposure to sea level rise, twelve are in Asia , including Indonesia , Bangladesh and the Philippines. The resilience and adaptive capacity of ecosystems and countries also varies, which will result in more or less pronounced impacts. The greatest impact on human populations in the near term will occur in the low-lying Caribbean and Pacific islands . Sea level rise will make many of them uninhabitable later this century. Pilots can estimate height above sea level with an altimeter set to
1064-555: The height of planetary features. Local mean sea level (LMSL) is defined as the height of the sea with respect to a land benchmark, averaged over a period of time long enough that fluctuations caused by waves and tides are smoothed out, typically a year or more. One must adjust perceived changes in LMSL to account for vertical movements of the land, which can occur at rates similar to sea level changes (millimetres per year). Some land movements occur because of isostatic adjustment to
1102-458: The land was granted as "Whitcherville" to James Avery and 60 others on January 31, 1764. But those settlers forfeited their grant by failure to comply with the requirements of the charter, so the territory was re-granted to Dartmouth College on January 19, 1770. Settlements were made under the Dartmouth grant. Roads and a mill were built at the expense of the college, and on November 11, 1774,
1140-591: The land; hence a change in relative MSL or ( relative sea level ) can result from a real change in sea level, or from a change in the height of the land on which the tide gauge operates, or both. In the UK, the ordnance datum (the 0 metres height on UK maps) is the mean sea level measured at Newlyn in Cornwall between 1915 and 1921. Before 1921, the vertical datum was MSL at the Victoria Dock, Liverpool . Since
1178-481: The melting of ice sheets at the end of the last ice age . The weight of the ice sheet depresses the underlying land, and when the ice melts away the land slowly rebounds . Changes in ground-based ice volume also affect local and regional sea levels by the readjustment of the geoid and true polar wander . Atmospheric pressure , ocean currents and local ocean temperature changes can affect LMSL as well. Eustatic sea level change (global as opposed to local change)
Landaff - Misplaced Pages Continue
1216-518: The times of the Russian Empire , in Russia and its other former parts, now independent states, the sea level is measured from the zero level of Kronstadt Sea-Gauge. In Hong Kong, "mPD" is a surveying term meaning "metres above Principal Datum" and refers to height of 0.146 m (5.7 in) above chart datum and 1.304 m (4 ft 3.3 in) below the average sea level. In France,
1254-473: The town was 96.56% White , 0.26% Native American , and 3.17% from two or more races. Hispanic or Latino of any race were 0.79% of the population. There were 154 households, out of which 29.2% had children under the age of 18 living with them, 61.7% were married couples living together, 6.5% had a female householder with no husband present, and 29.9% were non-families. 21.4% of all households were made up of individuals, and 11.0% had someone living alone who
1292-502: The town was incorporated. After the Revolutionary War , however, the first grantees successfully claimed that their forfeiture was illegal, so the college had to abandon its title and lose what it had expended in making the settlements. Landaff was originally much larger than today. It was changed by legislative actions over the years: The Lisbon Area Historical Society promotes the public's interest in and appreciation for
1330-594: The town. The highest point in Landaff is the summit of Moody Ledge in the south-central part of town, at 2,326 feet (709 m) above sea level . The Ammonoosuc River defines part of the northwestern boundary of the town, and the Wild Ammonoosuc River flows through the southern part of the town. Landaff lies fully within the Connecticut River watershed . The southern half of the town
1368-631: The towns of Lisbon, Landaff and Lyman, and maintains the collection, preservation and cataloging of materials which establish or illustrate the history of the three towns, their indigenous history and heritage, their exploration, settlement and development, as well as their cultural and artistic heritage. According to the United States Census Bureau , the town of Landaff has a total area of 28.5 square miles (73.8 km ), of which 28.3 square miles (73.4 km ) are land and 0.2 square miles (0.4 km ) are water, comprising 0.48% of
1406-411: The weight of cooling volcanos. The subsidence of land due to the withdrawal of groundwater is another isostatic cause of relative sea level rise. On planets that lack a liquid ocean, planetologists can calculate a "mean altitude" by averaging the heights of all points on the surface. This altitude, sometimes referred to as a "sea level" or zero-level elevation , serves equivalently as a reference for
1444-452: Was 65 years of age or older. The average household size was 2.45 and the average family size was 2.88. In the town, the population was spread out, with 23.8% under the age of 18, 5.6% from 18 to 24, 27.0% from 25 to 44, 28.8% from 45 to 64, and 14.8% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 93.8 males. For every 100 females age 18 and over, there were 95.9 males. The median income for
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