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60-602: Anacapa may refer to: Anacapa Island , an island near the coast of California Anacapa Island Lighthouse , a lighthouse on Anacapa Island USS  Anacapa  (AG-49) , a World War II Q-ship of the US Navy USCGC ; Anacapa  (WPB-1335) , an active cutter of the US Coast Guard Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

120-496: A 30,000-square-foot (2,800 m ) water catchment basin, and two large redwood water tanks housed in a building. Combined with their families, there were 15 to 25 residents on the island at any given time. Plans were implemented in 1962 to automate the facility and some buildings were demolished, though the houses were spared. The U.S. Coast Guard still owns the property, but the National Park Service moved into

180-409: 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,

240-432: 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

300-675: A new species in 1997. Introduced mammals on Anacapa Island included domestic cats , sheep , rabbits, and black rats. Black rats ( Rattus rattus ), also known as ship rats, had a major impact on wildlife on Anacapa Island, including seabirds such as Scripps's murrelet, reptiles and amphibians, intertidal and terrestrial invertebrates , and vegetation. Before a rat eradication program in 2001–2002, more than 96 percent of Scripps's Murrelet nests on Anacapa were attacked by invasive rats. The rats were certainly introduced sometime prior to 1939 (when they were noted by National Park Service researchers Sumner and Bond), probably in supplies brought onto

360-438: 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

420-470: 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

480-595: A single large island (dubbed " Santa Rosae ") that lay about 5 miles (4 nmi; 8 km) off the California coast. Fossils of pygmy mammoths from the Late Pleistocene period 13,000 years ago have been found on the other three northern islands and it is reasonable to assume pygmy mammoths were also present on Anacapa. In The Channel Islands of California (1910), Charles Frederick Holder says of Anacapa: Arid appearing, desolate, wind-swept, Anacapa

540-429: A stout, succulent trunk growing to some 8 ft (2 m) tall. The main trunk grows up to 5 in (13 cm) thick and often resembles a small tree. During its blooming season, March to May, it bursts forth with a mass of showy, bright yellow flowers and green leaves. Giant coreopsis provided shelter and perches for seabirds and land birds, and nesting habitat for many. The prolific seeds provided abundant food for

600-437: Is 250 ft (76 m) at its highest point. All three islands total 699 acres (283 ha), or about 1.1 square miles (2.8 km ). East Island's most notable natural feature is Arch Rock, a 40-foot (12 m) high natural bridge. As recently as the end of the last ice age (about 10,000 years ago), sea levels as much as 400 ft (122 m) lower than today meant that the four northern Channel Islands were part of

660-405: 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 is measured to calibrate altitude and, consequently, aircraft flight levels . A common and relatively straightforward mean sea-level standard

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720-488: 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)

780-427: 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

840-685: Is greatly moderated by the Pacific Ocean . According to the Köppen Climate Classification system, Anacapa Island has a warm-summer Mediterranean climate , abbreviated "Csb" on climate maps. Anacapa is the only one of the Channel Islands to have a non- Spanish -derived name. Anacapa comes from the Chumash word ' Anyapax , meaning "illusion". Juan Rodriguez Cabrillo passed by the island in 1542, but it

900-483: 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

960-408: 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 the amount of water in the oceans, while

1020-689: Is one of the MPAs existing in the Channel Island National Park. Public passenger access to Anacapa Island is provided by Island Packers ferry service out of either the Ventura Harbor or Channel Islands Harbor in Oxnard, California . Along with Santa Barbara Island , Anacapa was formed by volcanic eruptions between 19 and 15 million years ago. These eruptions are believed to have been caused by thinning of ocean crust as

1080-450: 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

1140-727: 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

1200-702: Is the smallest of the northern islands of the Channel Islands archipelago , and is within the Channel Islands National Park . It is 9 miles (7.8 nmi; 14 km) across the Santa Barbara Channel from the nearest point on the mainland. It lies southwest of the city of Ventura , California. The northern waters of Anacapa Island are protected by the Anacapa State Marine Reserve , which

1260-531: 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

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1320-459: Is withal a valuable possession to its owner, and one of the picturesque islands of the entire group. Its strange rocks, moving, passing, intermingling, made a strong impression on my mind, an impression of warring nature, conflicts of wind and rock, of seas eating into its very vitals, of caves that undermine it, and of the old rock fighting for its very life against the sea. Anacapa Island, located only about 11 mi (10 nmi; 18 km) from

1380-603: The California brown pelican in the United States, and one of only two in California, also occurs on Anacapa Island. This is where the brown pelican has been able to recover dramatically from near-extinction in the 1970s. The islets of Anacapa also host the largest breeding colony of western gulls in the world. Western gulls begin their nesting efforts at the end of April, sometimes making their shallow nests just inches from trails. Fluffy chicks hatch in May and June and fly away from

1440-622: 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

1500-418: 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

1560-562: 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

1620-445: The 1940s until at least 1965. No rabbits were recorded from Middle or West Anacapa. Domestic cats were introduced to Anacapa as pets of the fisherman "Frenchy" after whom Frenchy's Cove on West Island is named. In 1966, there remained a small population. Sheep were grazed on the island for many years. There are records from the 1870s through the 1930s. Many writers reported that in the absence of springs on Anacapa sheep would lick

1680-973: 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

1740-478: The Anacapa Light Station. Only small patches and individuals of native plants remained. Malacothrix junakii is a rare species of aster known by the common names Anacapa Island desert-dandelion, Junak's desert dandelion, and Junak's malacothrix that is endemic to Anacapa, where it is known from just two occurrences. It occurs in the coastal scrub of the island and was described to science as

1800-448: 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

1860-705: 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

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1920-539: The U.S. Coast Guard planted two types of iceplant on East Anacapa Islet: red-flowered iceplant ( Malephora crocea ) and sea fig, also called freeway iceplant ( Carpobrotus edulis x aequilaterus ) . Both species are highly invasive. The National Park Service has initiated a restoration project to eradicate all of the ice plant by 2016, the centennial of the National Park Service Organic Act . Vegetation on Anacapa began to recover after

1980-543: The United States . The next resident of the island was Raymond "Frenchy" LeDreau, who occupied four shacks on West Anacapa at Frenchy's Cove, living as a recluse for the next 30 years, departing the island in his eighties after the island had become a national monument . On a visit around 1910, Charles Frederick Holder noted " kitchen-middens , and deposits of ancient shells, and the tell-tale black earth " of hearths . The United States Lighthouse Service built an acetylene -powered light and whistling buoy in 1912 at

2040-471: The block containing the northern Channel Islands and Santa Monica Mountains was rotated clockwise by the transverse motion of the Pacific and North American plates . Lava from these eruptions can be found across the region, and in depths of up to 10,000 feet (3,000 m). The rocks that make up Anacapa are composed of lava , breccias , volcanic ash , and cinders . Erosion has heavily weathered

2100-608: The east end of the island, and constructed the East Anacapa Island Light between 1930 and 1932. It was the last lighthouse built by the Lighthouse Service on the California coast. The facility was staffed by U.S. Coast Guard six-man crews serving two-year tours of duty from 1939 onwards. The facility included Mission Revival houses , a heavy-lift boom for raising supply boats , three 2,000-US-gallon (1,700 imp gal; 7,600 L) fuel tanks,

2160-507: The endemic Anacapa deer mouse, and for many small birds. The island's stands of giant coreopsis, as well as all the other plants of its coastal bluff community, were devastated by sheep grazing in the late 1800s and early 1900s, rabbit browsing in 1910-1950s, and by large-scale destruction of native vegetation associated with facility and road development by the United States Coast Guard during construction and manning of

2220-415: 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

2280-482: 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

2340-634: 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

2400-555: 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

2460-437: The island for sheep ranching or building the lighthouse. The National Park Service says there is evidence they were present in 1907. A 1979 study noted that they could have been introduced from a shipwreck , such as that of SS  Winfield Scott in 1853. European rabbits were introduced to East Island either as an emergency food supply for lighthouse personnel during World War II or as pets. They were present from

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2520-615: The island is in Census Tract 36.12 of Ventura County, California. The official 2000 census population was three permanent residents, all at the ranger station in the eastern part of East Island. 34°00′14″N 119°23′41″W  /  34.00389°N 119.39472°W  / 34.00389; -119.39472 Sea level Mean sea level ( MSL , often shortened to sea level ) 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

2580-412: The island) plus many introduced species . Anacapa has around 69 species of birds. The island's steep lava rock cliffs incorporate numerous caves and crevices that are particularly important for the increasingly rare seabird Scripps's murrelet (a threatened species known as Xantus's murrelet until 2012). The cliffs are also an important location for the ashy storm-petrel . The largest breeding colony of

2640-541: The island, starting in the 1850s or 1860s. Louis le Mesnager then signed a five-year lease with the United States Government around 1897, but his lease and sheep were taken over by Herman Bayfield Webster in 1907. His Sheep Camp operation was located on Middle Anacapa, which included five shacks and about 500 sheep. Ira Eaton acquired the lease in 1917 and held it until 1927, and used the island for his bootleg alcohol operation during Prohibition in

2700-591: 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

2760-565: The lava formations of Anacapa, and wave action caused the island to split into three islets in recent prehistoric times. The islets display a wide variety of erosional features including sea arches , sea caves , stacks , wave-cut platforms , surge channels , and blowholes . West Anacapa is the largest and highest islet, rising to an altitude of 930 ft (283 m) at Vela Peak, also known as Summit Peak 2. East and Middle Anacapa have fairly level areas at their tops. Middle Island reaches an altitude of 325 ft (99 m) and East Island

2820-424: The less-common California alligator lizard ( Elgaria multicarinata multicarinata). There is one amphibian, the Channel Islands slender salamander ( Batrachoseps pacificus ). Marine mammals and other marine life abound on Anacapa. Anacapa's prolific and dense vegetation was once dominated by the showy giant coreopsis ( Leptosyne gigantea ) previously named Coreopsis gigantea , an erect, shrubby perennial with

2880-481: 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)

2940-425: The moisture that accumulated on each other's fleeces from the coastal fog. The native flora was affected by the forage grasses that farmers introduced to feed their flocks, and by soil-compaction caused by the sheep's hooves. Reproduction of ground-nesting species such as the meadowlark and horned lark is also thought to have been harmed by grazing. After completion of the lighthouse and associated facilities,

3000-459: The nests in July. The only native land mammal on the island is a unique subspecies of deer mouse ( Peromyscus maniculatus anacapae ) which occurs on all three islets, but nowhere else. ( San Clemente Island in the southern Channel Islands also has an endemic subspecies of deer mouse.) Anacapa has two native reptiles: an endemic form of the side-blotched lizard ( Uta stansburiana hesperis ); and

3060-553: The removal of sheep about 1938 and rabbits in the 1950s. Black rats were successfully eradicated from Anacapa Island by 2003, under a controversial program that involved an aerial application of the rodenticide brodifacoum with the assistance of Island Conservation . This was the first time a rodenticide had been applied aerially in North America (the technique was pioneered in New Zealand ). One complicating factor

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3120-566: The residences in 1970, while sharing the wharf and hoist facilities. Frenchy's Cove was cleaned up starting in June 1959, and a permanent park ranger replaced the seasonal one in the mid-1970s. On January 31, 2000, Alaska Airlines Flight 261 crashed near the island following a catastrophic loss of pitch control caused by jackscrew , killing all 88 people aboard. Along with the Channel Islands Beach area of Port Hueneme,

3180-456: The result of a study, PVA determined that a population of 333 deer mice had a high chance of survival. Approximately 300 deer mice were captured prior to the application of rodenticide and reintroduced after poison levels had dropped, which was about three months. The program cost about $ 1.8 million. A study after the eradication project showed that nesting attempts by Scripps's murrelets on Anacapa had more than doubled, average hatching success

3240-518: 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,

3300-455: The title Anacapa . 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=Anacapa&oldid=1075965770 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Anacapa Island Anacapa

3360-414: The urbanized coast of Southern California ], provides a critical habitat for seabirds , pinnipeds such as California sea lions , and several endemic plants and animals. Great white sharks , feeding on pinnipeds, are found in the waters of the Channel Islands, including Anacapa. The island has a somewhat diverse flora, including around 150 native plants, including 16 endemics (two of which are unique to

3420-411: 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

3480-499: Was George Vancouver who labeled it Enecapa on his 1790 chart, while the United States Coast and Geodetic Survey labeled it Anacapa in 1854. On the night of December 2, 1853, the sidewheel steamer SS  Winfield Scott , running at full speed, crashed into the rocks off Middle Anacapa and sank. All of the passengers survived and were rescued after a week. George Nidever was the first person to raise sheep on

3540-418: Was the presence of the native deer mouse subspecies ( Peromyscus maniculatus anacapae ). This was the first time that biologists had attempted to eradicate one rodent species from an entire island where an endemic rodent was present. A tool called Population Viability Analysis, or PVA, is a species-specific method used to assess the probability of a population's extinction in a given number of years. Based on

3600-509: Was up from 42 to 80 percent, and average nest predation was down from 52 to 7 percent. Only four months after the rodenticide applications, Cassin's auklet ( Ptychoramphus aleuticus ) began nesting on Anacapa. This was significant as there were no previous records of the bird nesting on the island and it is known to be highly susceptible to rat predation. The region experiences warm and dry summers and mild winters with no average monthly temperatures above 71.6 °F (22.0 °C). Its climate

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