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107-412: A weather instrument is any device that measures weather related conditions. Since there are a variety of different weather conditions, there are a variety of different weather instruments. Typical weather stations have the following instruments: In addition, at certain automated airport weather stations , additional instruments may be employed, including: More sophisticated stations may also measure

214-434: A chilled mirror that is cooled to the point where a fine film of condensation forms on the mirror's surface. The temperature of the mirror at this condition is equal to the dew point temperature. The hygrometer measures the dew point by directing a light beam from a small infrared diode to the surface of the mirror at an angle of 45 degrees. Two photo transistors are mounted so they measure a high degree of reflected light when

321-421: A forward scatter sensor. Forward scatter sensors are more popular due to their lower price, smaller size and lower maintenance requirements. However, transmissometers are still used at some airports as they are more accurate at low visibilities and are fail-safe, i.e. in case of failure report visibility lower than actual. Current sensors are capable of reporting visibility in a wide range. For aviation purposes,

428-446: A pattern analysis of the particle size and fall velocity whether the precipitation is rain or snow . If precipitation is determined to be falling, but the pattern is not conclusively identified as either rain or snow, unknown precipitation is reported. Automated airport weather stations are not yet able to report hail , ice pellets , and various other intermediate forms of precipitation. Automated airport weather stations do not have

535-506: A personal computer, and internet connection (or amateur radio) and are utilized by groups such as the National Weather Service (NWS) when generating forecast models . Each weather station submitting data to CWOP will also have an individual Web page that depicts the data submitted by that station. The Weather Underground Internet site is another popular destination for the submittal and sharing of data with others around

642-731: A report of freezing rain. If the LEDWI reports either no precipitation or snow, the system will ignore the input from the freezing rain sensor. The sensor is designed to detect and report icing from all weather conditions. Many automated airport weather stations within the United States use the National Lightning Detection Network ( NLDN ) to detect lightning via the automatic lightning detection and reporting system ( ALDARS ). The NLDN uses 106 sensors nationwide to triangulate lightning strikes. Data from

749-416: A separate sensor for detecting specific obscurations to vision. Instead, when visibility is reduced below 7 statute miles , the system uses the reported temperature and dew point to determine an obscuration to vision. If relative humidity is low (i.e., there is a large difference between the temperature and dew point), haze is reported. If relative humidity is high (i.e., there is a small difference between

856-415: A thermocouple in reverse, producing a heating or cooling effect. When the sensor is first activated, the mirror is clear. As the mirror surface temperature is cooled to the dew point temperature, condensations forms on the mirror. The electronics continuously tries to stabilize the signal levels to the power amplifier to maintain the mirror temperature at the dew point. If the dew point of the air changes or if

963-412: A thunderstorm in the vicinity of the station (VCTS). Lightning more than 10 miles (16 km) but less than 30 miles (48 km) from the station results only in a remark of distant lightning (LTG DSNT). However, some stations now have their own lightning sensor to actually measure lightning strikes at the site rather than requiring an external service. This thunderstorm sensor works by detecting both

1070-558: A valuable resource. The last weather ship was MS  Polarfront , known as weather station M ("jilindras") at 66°N, 02°E, run by the Norwegian Meteorological Institute . MS Polarfront was removed from service January 1, 2010. Since the 1960s this role has been largely superseded by satellites , long range aircraft and weather buoys . Weather observations from ships continue from thousands of voluntary merchant vessels in routine commercial operation;

1177-792: A variety of meteorological conditions. These include: Because many of these can pose dangers to aircraft and all of these are of interest to the meteorological community, most of the busier airports also have part-time or full-time human observers who augment, or provide additional information to, the automated airport weather station's observations. Research is on-going to allow the automated stations to detect many of these phenomena. Automated stations can also suffer from mechanical breakdown, requiring repair or replacement. This can be either due to physical damage (either natural or human caused), mechanical wear, or severe icing during winter weather. During system outages, human observers are often required to supplement missing or non-representative observations from

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1284-408: A variety of sophisticated equipment to observe the weather. A majority of older automated airport weather stations are equipped with a mechanical wind vane and cup system to measure wind speed and direction. This system is simple in design: the wind spins three horizontally turned cups around the base of the wind vane, providing an estimation of the wind's speed, while the vane on top turns so that

1391-448: A variety of ways: The following AWOS configurations are defined below in terms of what parameters they measure: Also, custom configurations such as AWOS AV (AWOS A parameters plus visibility) are possible. Non-certified sensors may be attached to AWOS systems, but weather data derived from those sensors must be clearly identified as "advisory" in any voice messages and may not be included in any METAR observations. As of May 22, 2022,

1498-401: A vibrating rod. The resonant frequency decreases with increasing accretion (additional mass) of ice , hoarfrost , freezing fog, freezing drizzle , rime , or wet snow. To report freezing rain, the system combines the sensor output from the freezing rain sensor with data from the LEDWI. The LEDWI must provide a positive indication of unknown precipitation or rain before the system can transmit

1605-542: Is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km (170,000,000 cu mi). Due to the effects of plate tectonics , the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size. Along

1712-457: Is accumulated. That amount of weight causes the bucket to tip on its pivots , dumping the collected water and moving the other chamber under the funnel. The tipping motion activates a switch (either a reed switch or a mercury switch ), which sends one electrical pulse for each 0.01-inch (0.25 mm) of precipitation collected. Because of problems the heated tipping bucket has with properly measuring frozen precipitation (particularly snow),

1819-545: Is calculated. Data from a barometric pressure sensor are used to calculate QNH altimeter setting . Pilots rely on this value to determine their altitude . To ensure safe separation from terrain and other obstructions, high degree of accuracy and reliability is required from a pressure sensor. Most aviation weather stations use two (required for an AWOS) or three independent pressure transducers. The transducers may or may not share their associated tubing and external ports (designed to minimize effect of wind/wind gusts). Should

1926-643: Is located at an airport; for example, one of these units is located at Belvedere Castle in Central Park , New York City ; another is located at the Blue Hill Observatory near Boston , Massachusetts . The FAA has converted all automated weather sensor system ( AWSS ) units to AWOS III P/T units. There are no AWSS systems remaining in the US National Airspace System (NAS). Automated airport weather stations use

2033-491: Is not known with any certainty what level of maritime technology was used by these groups – the presumption is that they used large bamboo rafts which may have been equipped with some sort of sail. The reduction in favourable winds for a crossing to Sahul after 58,000 B.P. fits with the dating of the settlement of Australia, with no later migrations in the prehistoric period. The seafaring abilities of pre-Austronesian residents of Island South-east Asia are confirmed by

2140-929: Is required for record keeping. Automatic transmission of data, in a format such as METAR , is also desirable as many weather station's data is required for weather forecasting. A personal weather station is a set of weather measuring instruments operated by a private individual, club, association, or business (where obtaining and distributing weather data is not a part of the entity's business operation). Personal weather stations have become more advanced and can include many different sensors to measure weather conditions. These sensors can vary between models but most measure wind speed, wind direction, outdoor and indoor temperatures, outdoor and indoor humidity, barometric pressure, rainfall, and UV or solar radiation. Other available sensors can measure soil moisture, soil temperature, and leaf wetness. The quality, number of instruments, and placement of personal weather stations can vary widely, making

2247-552: Is simple compared to the dew point. Operating under the principle that electrical resistance varies with temperature, a platinum wire resistive temperature device measures the ambient air temperature. The current ASOS thermometer is designated the HO-1088, though some older systems still utilize the HO-83. In contrast, the dew point measurement is considerably more complex. The original dew point sensor deployed on ASOS systems utilized

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2354-697: The Americas , although evidence for this remains inconclusive. The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of António de Abreu and Francisco Serrão , via the Lesser Sunda Islands , to the Maluku Islands , in 1512, and with Jorge Álvares 's expedition to southern China in 1513, both ordered by Afonso de Albuquerque from Malacca . The eastern side of

2461-575: The Bering Sea in the Arctic to the northern extent of the circumpolar Southern Ocean at 60°S (older definitions extend it to Antarctica 's Ross Sea ), the Pacific reaches its greatest east–west width at about 5°N latitude , where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast of Colombia  – halfway around the world, and more than five times

2568-569: The International Civil Aviation Organization (ICAO) established a global network of 13 weather ships in 1948. Of the 12 left in operation in 1996, nine were located in the northern Atlantic Ocean while three were located in the northern Pacific Ocean . The agreement of the weather ships ended in 1990. Weather ship observations proved to be helpful in wind and wave studies, as they did not avoid weather systems like merchant ships tended to and were considered

2675-829: The International Date Line into the East Pacific and the West Pacific , which allows it to be further divided into four quadrants, namely the Northeast Pacific off the coasts of North America , the Southeast Pacific off South America , Northwest Pacific off Far Eastern / Pacific Asia , and the Southwest Pacific around Oceania . The Pacific Ocean's mean depth is 4,000 meters (13,000 feet). Challenger Deep in

2782-830: The Mariana Trench , located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet). The Pacific also contains the deepest point in the Southern Hemisphere , the Horizon Deep in the Tonga Trench , at 10,823 meters (35,509 feet). The third deepest point on Earth, the Sirena Deep , is also located in the Mariana Trench. The western Pacific has many major marginal seas , including

2889-484: The Old Weather crowdsourcing project transcribes naval logs from before the era of dedicated ships. Weather buoys are instruments which collect weather and oceanography data within the world's oceans and lakes. Moored buoys have been in use since 1951, while drifting buoys have been used since the late 1970s. Moored buoys are connected with the seabed using either chains, nylon , or buoyant polypropylene . With

2996-538: The Pacific War ; however, by the end of that war, Japan was defeated and the U.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruled Northern Mariana Islands came under the control of the United States. Since the end of World War II, many former colonies in the Pacific have become independent states . The Pacific separates Asia and Australia from the Americas. It may be further subdivided by

3103-631: The Philippine Sea , South China Sea , East China Sea , Sea of Japan , Sea of Okhotsk , Bering Sea , Gulf of Alaska , Gulf of California , Mar de Grau , Tasman Sea , and the Coral Sea . In the early 16th century , Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and sighted the great "Southern Sea" which he named Mar del Sur (in Spanish). Afterwards,

3210-715: The Southern Hemisphere . The North Equatorial Current , driven westward along latitude 15°N by the trade winds , turns north near the Philippines to become the warm Japan or Kuroshio Current . Turning eastward at about 45°N , the Kuroshio forks and some water moves northward as the Aleutian Current , while the rest turns southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms

3317-685: The Strait of Magellan to the Philippines , the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Many tropical storms batter the islands of the Pacific. The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes . Tsunamis , caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns. The Martin Waldseemüller map of 1507

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3424-800: The Water Hemisphere and the Western Hemisphere , as well as the oceanic pole of inaccessibility , are in the Pacific Ocean. Ocean circulation (caused by the Coriolis effect ) subdivides it into two largely independent volumes of water that meet at the equator , the North Pacific Ocean and the South Pacific Ocean (or more loosely the South Seas ). The Pacific Ocean can also be informally divided by

3531-750: The Western Hemisphere . The Southern Pacific Ocean harbors the Southeast Indian Ridge crossing from south of Australia turning into the Pacific-Antarctic Ridge (north of the South Pole ) and merges with another ridge (south of South America) to form the East Pacific Rise which also connects with another ridge (south of North America) which overlooks the Juan de Fuca Ridge . For most of Magellan's voyage from

3638-451: The all-weather precipitation accumulation gauge ( AWPAG ) was developed. This sensor is essentially a weighing gauge where precipitation continuously accumulates within the collector, and as the weight increases, precipitation is recorded. Only select NWS ASOS units have been equipped with the AWPAG. Automated airport weather stations report freezing rain via the resonant frequency of

3745-583: The crab claw sail ) – it is likely that the progressive development of these technologies were related to the later steps of settlement into Near and Remote Oceania. Starting at around 2200 BCE, Austronesians sailed southwards to settle the Philippines . From, probably, the Bismarck Archipelago they crossed the western Pacific to reach the Marianas Islands by 1500 BCE, as well as Palau and Yap by 1000 BCE. They were

3852-521: The ultraviolet index , leaf wetness , soil moisture , soil temperature, water temperature in ponds, lakes, creeks, or rivers, and occasionally other data. Except for those instruments requiring direct exposure to the elements (anemometer, rain gauge), the instruments should be sheltered in a vented box, usually a Stevenson screen , to keep direct sunlight off the thermometer and wind off the hygrometer. The instrumentation may be specialized to allow for periodic recording, otherwise significant manual labour

3959-908: The Atlantic, the Strait of Magellan was at times patrolled by fleets sent to prevent the entrance of non-Spanish ships. On the western side of the Pacific Ocean the Dutch threatened the Spanish Philippines . The 18th century marked the beginning of major exploration by the Russians in Alaska and the Aleutian Islands , such as the First Kamchatka expedition and the Great Northern Expedition , led by

4066-533: The Atlantic. The andesite line is the most significant regional distinction in the Pacific. A petrologic boundary, it separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins. The andesite line follows the western edge of the islands off California and passes south of the Aleutian arc , along

4173-735: The Chilean coast, the South Equatorial Current divides; one branch flows around Cape Horn and the other turns north to form the Peru or Humboldt Current . The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The trade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on

4280-844: The Danish-born Russian navy officer Vitus Bering . Spain also sent expeditions to the Pacific Northwest , reaching Vancouver Island in southern Canada, and Alaska. The French explored and colonized Polynesia , and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii , and the North American Pacific Northwest . In 1768, Pierre-Antoine Véron , a young astronomer accompanying Louis Antoine de Bougainville on his voyage of exploration, established

4387-768: The FAA non-federal AWOS Program. The FAA completed an upgrade of the 230 FAA owned AWOS and former automated weather sensor systems (AWSS) systems to the AWOS-C configuration in 2017. The AWOS-C is the most up-to-date FAA owned AWOS facility and can generate METAR/SPECI formatted aviation weather reports. The AWOS-C is functionally equivalent to the ASOS. FAA owned AWOS-C units in Alaska are typically classified as AWOS-C IIIP units while all other AWOS-C units are typically classified as AWOS III P/T units. AWOS systems disseminate weather data in

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4494-679: The Moluccas, between 1525 and 1527, Portuguese expeditions encountered the Caroline Islands , the Aru Islands , and Papua New Guinea . In 1542–43 the Portuguese also reached Japan. In 1564, five Spanish ships carrying 379 soldiers crossed the ocean from Mexico led by Miguel López de Legazpi , and colonized the Philippines and Mariana Islands . For the remainder of the 16th century, Spain maintained military and mercantile control, with ships sailing from Mexico and Peru across

4601-802: The Pacific Ocean to the Philippines via Guam , and establishing the Spanish East Indies . The Manila galleons operated for two and a half centuries, linking Manila and Acapulco , in one of the longest trade routes in history. Spanish expeditions also arrived at Tuvalu , the Marquesas , the Cook Islands , the Solomon Islands , Vanuatu , the Marshalls and the Admiralty Islands in the South Pacific. Later, in

4708-518: The Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea , Coral Sea , East China Sea (East Sea), Philippine Sea , Sea of Japan , South China Sea (South Sea), Sulu Sea , Tasman Sea , and Yellow Sea (West Sea of Korea). The Indonesian Seaway (including the Strait of Malacca and Torres Strait ) joins the Pacific and the Indian Ocean to

4815-472: The Pacific in prehistoric times. Modern humans first reached the western Pacific in the Paleolithic , at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reached East Asia , Mainland Southeast Asia , the Philippines, New Guinea , and then Australia by making the sea crossing of at least 80 kilometres (50 mi) between Sundaland and Sahul . It

4922-512: The Pacific in recorded history. They were part of a Spanish expedition to the Spice Islands that would eventually result in the first world circumnavigation . Magellan called the ocean Pacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off Cape Horn , the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until

5029-653: The Philippines already in 7000 BCE. Additional earlier migrations into Insular Southeast Asia, associated with Austroasiatic-speakers from Mainland Southeast Asia, are estimated to have taken place already in 15000 BCE. At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as the Lapita culture reached the Bismarck Archipelago , the Solomon Islands , Vanuatu , Fiji , and New Caledonia . From there, they settled Tonga and Samoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle

5136-528: The United States. Significant contributions to oceanographic knowledge were made by the voyages of HMS Beagle in the 1830s, with Charles Darwin aboard; HMS Challenger during the 1870s; the USS Tuscarora (1873–76); and the German Gazelle (1874–76). In Oceania, France obtained a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853, respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro negotiated

5243-421: The air and received by the receiver determines the extinction coefficient. This is then converted to visibility using either Allard's or Koschmieder's law. In a transmissometer, a beam of visible light is transmitted from its transmitter to receiver head. The extinction coefficient is derived from the amount of light lost in the air. There also are sensors that, to a certain degree combine a transmissometer with

5350-410: The amount and height of clouds. The laser is pointed upward, and the time required for reflected light to return to the station allows for the calculation of the height of the cloud base. Because of the limited coverage area (the laser can only detect clouds directly overhead), the system computer calculates a time-averaged cloud cover and ceiling , which is reported to external users. To compensate for

5457-416: The andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Some of these islands are structurally associated with nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these are Bougainville , Hawaii, and the Solomon Islands. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under

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5564-408: The andesite line. Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and

5671-409: The arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between

5778-436: The automated station. Research is also ongoing to produce more robust systems which are less vulnerable to natural damage, mechanical wear and icing. Pacific Ocean Main five oceans division: Further subdivision: The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions . It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica ) in

5885-536: The automated weather observation. This is often via the automatic terminal information service (ATIS). Most automated weather stations also have discrete phone numbers to retrieve real-time observations over the phone or through a modem. In the United States, the AWOS/ASOS data acquisition system (ADAS), a computer system run by the FAA, polls the systems remotely, accessing the observations and disseminating them worldwide electronically in METAR format. At present, automated airport weather stations are unable to report

5992-612: The backbone of weather observing in the United States and Canada and are becoming increasingly more prevalent worldwide due to their efficiency and cost-savings. In the United States, there are several varieties of automated weather stations that have somewhat subtle but important differences. These include the automated weather observing system ( AWOS ) and the automated surface observing system ( ASOS ). The automated weather observing system ( AWOS ) units are mostly operated, maintained and controlled by state or local governments and other non-federal entities and are certified under

6099-421: The base of a counter-clockwise circulation in the Bering Sea . Its southern arm becomes the chilled slow, south-flowing California Current . The South Equatorial Current , flowing west along the equator, swings southward east of New Guinea , turns east at about 50°S , and joins the main westerly circulation of the South Pacific, which includes the Earth-circling Antarctic Circumpolar Current . As it approaches

6206-404: The circuit is disturbed by noise, the loop makes the necessary corrections to restabilize at the dew point and maintaining continuous operation. Due to problems with the chilled mirror sensor, NWS ASOS sites now use Vaisala's DTS1 sensor, which measures humidity only via capacitance . The sensor is based on a solid state capacitive relative humidity element that incorporates a small heater so that

6313-526: The danger of rapidly changing sky cover, the averaging is weighted toward the first 10 minutes of the 30-minute averaging period. The range of the ceilometer is up to 25,000 feet (7,600 m) depending on the model. Clouds above that height are not detectable by automated stations at present. Automated airport weather stations use a temperature/dew point sensor ( hygrothermometer ) designed for continuous operation which normally remains on at all times, except during maintenance. The measurement of temperature

6420-456: The decline of the weather ship , they have taken a more primary role in measuring conditions over the open seas since the 1970s. During the 1980s and 1990s, a network of buoys in the central and eastern tropical Pacific Ocean helped study the El Niño-Southern Oscillation . Moored weather buoys range from 1.5–12 metres (5–40 ft) in diameter, while drifting buoys are smaller, with diameters of 30–40 centimetres (12–16 in). Drifting buoys are

6527-406: The detection grid is fed into ALDARS, which in turn sends messages to each automated airport station informing it of the proximity of any lightning strikes. Lightning strikes within 5 miles (8.0 km) of the station result in a report of a thunderstorm at the station (TS). Lightning strikes more than 5 miles (8.0 km) but less than 10 miles (16 km) from the station result in a report of

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6634-592: The determination of which stations collect accurate, meaningful, and comparable data difficult. There are a comprehensive number of retail weather stations available. Personal weather stations typically involve a digital console that provides readouts of the data being collected. These consoles may interface to a personal computer where data can be displayed, stored, and uploaded to websites or data ingestion/distribution systems. Open-source weather stations are available that are designed to be fully customizable by users. Personal weather stations may be operated solely for

6741-408: The diameter of the Moon. Its geographic center is in eastern Kiribati south of Kiritimati , just west from Starbuck Island at 4°58′S 158°45′W  /  4.97°S 158.75°W  / -4.97; -158.75 . The lowest known point on Earth – the Mariana Trench  – lies 10,911 m (35,797  ft ; 5,966 fathoms ) below sea level. Its average depth

6848-402: The difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all the tropical cyclone basins are active. The Pacific hosts the two most active tropical cyclone basins , which are

6955-866: The dominant form of weather buoy in sheer number, with 1250 located worldwide. Wind data from buoys has smaller error than that from ships. There are differences in the values of sea surface temperature measurements between the two platforms as well, relating to the depth of the measurement and whether or not the water is heated by the ship which measures the quantity. Synoptic weather stations are instruments which collect meteorological information at synoptic time 00h00, 06h00, 12h00, 18h00 ( UTC ) and at intermediate synoptic hours 03h00, 09h00, 15h00, 21h00 (UTC). Every weather station has assigned station unique code by WMO for identification. The common instruments of measure are anemometer, wind vane, pressure sensor, thermometer, hygrometer, and rain gauge. The weather measures are formatted in special format and transmit to WMO to help

7062-434: The east and the islands of Kiribati in the southeast. Melanesia, to the southwest, includes New Guinea , the world's second largest island after Greenland and by far the largest of the Pacific islands. The other main Melanesian groups from north to south are the Bismarck Archipelago , the Solomon Islands , Santa Cruz , Vanuatu , Fiji and New Caledonia . The largest area, Polynesia , stretching from Hawaii in

7169-423: The east coast of Russia contrasting with the milder weather off British Columbia during the winter months due to the preferred flow of ocean currents . In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately 3,000 km (1,900 mi) to

7276-403: The eastern edge of the Kamchatka Peninsula , the Kuril Islands , Japan, the Mariana Islands , the Solomon Islands , and New Zealand's North Island . The dissimilarity continues northeastward along the western edge of the Andes Cordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside

7383-410: The eighteenth century. Magellan stopped at one uninhabited Pacific island before stopping at Guam in March 1521. Although Magellan himself died in the Philippines in 1521, Spanish navigator Juan Sebastián Elcano led the remains of the expedition back to Spain across the Indian Ocean and round the Cape of Good Hope , completing the first world circumnavigation in 1522. Sailing around and east of

7490-411: The enjoyment and education of the owner, while some owners share their results with others. They do this by manually compiling data and distributing it, distributing data over the Internet, or sharing data via amateur radio . The Citizen Weather Observer Program (CWOP) is a service which facilitates the sharing of information from personal weather stations. This data is submitted through use of software,

7597-487: The equator into northern (North Pacific) and southern (South Pacific) portions. It extends from the Antarctic region in the South to the Arctic in the north. The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km (63,800,000 sq mi) – larger than Earth's entire landmass combined, 150,000,000 km (58,000,000 sq mi). Extending approximately 15,500 km (9,600 mi) from

7704-601: The equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas. The motion of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific gyre ) and counter-clockwise in

7811-412: The face of the vane offers the least resistance to the wind, causing it to point in the direction the wind is coming from and thus providing the wind direction. The new generation of sensors use sound waves to measure wind speed and direction. The measurement is based on the time it takes for an ultrasonic pulse to travel from one transducer to another, which varies depending on - among other factors -

7918-606: The first completely documented European landing in Australia (1606), in Cape York Peninsula , and Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived at Tasmania and New Zealand in 1642. In the 16th and 17th centuries, Spain considered the Pacific Ocean a mare clausum  – a sea closed to other naval powers. As the only known entrance from

8025-474: The first humans to reach Remote Oceania , and the first to cross vast distances of open water. They also continued spreading southwards and settling the rest of Maritime Southeast Asia , reaching Indonesia and Malaysia by 1500 BCE, and further west to Madagascar and the Comoros in the Indian Ocean by around 500 CE. More recently, it is suggested that Austronesians expanded already earlier, arriving in

8132-466: The flash of light and momentary change in the electric field produced by lightning. When both of these are detected within a few milliseconds of each other, the station registers a possible lightning strike. When a second possible lightning strike is detected within 15 minutes of the first, the station records a thunderstorm. Data dissemination is usually via an automated VHF airband radio frequency (108-137 MHz) at each airport , broadcasting

8239-584: The following manufacturers provide FAA-certified, non-federal AWOS systems: The automated surface observing system ( ASOS ) units are operated and controlled cooperatively in the United States by the NWS, FAA, and DOD. After many years of research and development, the deployment of ASOS units began in 1991 and was completed in 2004. These systems generally report at hourly intervals, but also report special observations if weather conditions change rapidly and cross aviation operation thresholds. They generally report all

8346-399: The ground, wind speed and direction are measured at 30 feet (9.1 meters). To determine visibility, automated airport weather stations use one of two sensor types: The forward scatter sensor uses a beam of infrared light which is sent from one end of the sensor toward the receiver, but offset from a direct line to the receiver by a certain angle. The amount of light scattered by particles in

8453-439: The incorporation of the island into Chile with native Rapanui in 1888. By occupying Easter Island, Chile joined the imperial nations. By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile. Although the United States gained control of Guam and the Philippines from Spain in 1898, Japan controlled most of the western Pacific by 1914 and occupied many other islands during

8560-547: The islands in the world. There are about 25,000 islands in the Pacific Ocean. The islands entirely within the Pacific Ocean can be divided into three main groups known as Micronesia , Melanesia and Polynesia . Micronesia, which lies north of the equator and west of the International Date Line , includes the Mariana Islands in the northwest, the Caroline Islands in the center, the Marshall Islands to

8667-575: The islands of eastern Micronesia (including the Carolines , the Marshall Islands , and Kiribati ), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion into Polynesia until around 700 CE when there was another surge of island exploration. They reached the Cook Islands , Tahiti , and the Marquesas by 700 CE; Hawaiʻi by 900 CE; Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE. Austronesians may have also reached as far as

8774-442: The mirror is clear (direct) and scattered light when the mirror is clouded with visible condensation (indirect). With the formation of condensation on the mirror, the degree of cloudiness of the mirror surface increases with the direct transistor receiving less light and the indirect transistor more light. The output from these photo transistors controls the mirror cooling module which is an electronic heat pump that operates much like

8881-601: The north to New Zealand in the south, also encompasses Tuvalu , Tokelau , Samoa , Tonga and the Kermadec Islands to the west, the Cook Islands , Society Islands and Austral Islands in the center, and the Marquesas Islands , Tuamotu , Mangareva Islands , and Easter Island to the east. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Continental islands lie outside

8988-619: The northern Philippines , but also earlier groups associated with Austroasiatic-speakers , resulting in the modern peoples of Island Southeast Asia and Oceania. A later seaborne migration is the Neolithic Austronesian expansion of the Austronesian peoples . Austronesians originated from the island of Taiwan c.  3000 –1500 BCE. They are associated with distinctive maritime sailing technologies (notably outrigger boats , catamarans , lashed-lug boats, and

9095-575: The northwestern Pacific and the eastern Pacific. Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, while typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the South Pacific basin , where they occasionally impact island nations. In

9202-451: The ocean was encountered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and reached a new ocean. He named it Mar del Sur ("Sea of the South" or "South Sea" ) because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. In 1520, navigator Ferdinand Magellan and his crew were the first to cross

9309-465: The ocean's current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favorable winds on reaching the ocean. He called it Mar Pacífico , which in Portuguese means 'peaceful sea'. Top large seas: Across the continents of Asia, Australia and the Americas , more than 25,000 islands, large and small, rise above

9416-562: The ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia . The volume of the Pacific Ocean, representing about 50.1 percent of

9523-496: The parameters of the AWOS-III, while also having the additional capabilities of reporting temperature and dew point in degrees Fahrenheit, present weather , icing , lightning , sea level pressure and precipitation accumulation. Besides serving aviation needs, ASOS serves as a primary climatological observing network in the United States, making up the first-order network of climate stations. Because of this, not every ASOS

9630-581: The quest for Terra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator Pedro Fernandes de Queirós , arrived at the Pitcairn and Vanuatu archipelagos, and sailed the Torres Strait between Australia and New Guinea, named after navigator Luís Vaz de Torres . Dutch explorers, sailing around southern Africa, also engaged in exploration and trade; Willem Janszoon , made

9737-513: The reported pressures differ by more than a preset maximum, the pressure values are discarded and altimeter setting is not reported or is reported as "missing." Altimeter setting is calculated based on barometric pressure, site elevation, sensor elevation and - optionally - air temperature. Altimeter setting is reported in inches of mercury (in steps of 0.01 inHg) or whole hectopascals, rounded down. The original precipitation accumulation measuring device used for automated airport weather stations

9844-425: The reported values are rounded down to the nearest step in one of the following scales: Automated airport weather stations use a light emitting diode weather identifier ( LEDWI ) to determine if and what type of precipitation is falling. The LEDWI sensor measures the scintillation pattern of the precipitation falling through the sensor's infrared beam (approximately 50 millimeters in diameter) and determines from

9951-413: The sensing element is always above the ambient temperature, eliminating the formation of dew or frost. The sensor reports directly in dew point through a calculation based on measured relative humidity and the measured temperature of the heated capacitive element. Older AWOS systems used a lithium chloride dew point sensor. Current AWOS systems use capacitive relative humidity sensors, from which dew point

10058-505: The settlement of Buka by 32,000 B.P. and Manus by 25,000 B.P. Journeys of 180 kilometres (110 mi) and 230 kilometres (140 mi) are involved, respectively. The descendants of these migrations today are the Negritos , Melanesians , and Indigenous Australians . Their populations in maritime Southeast Asia , coastal New Guinea , and Island Melanesia later intermarried with the incoming Austronesian settlers from Taiwan and

10165-550: The south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), this largest division of the World Ocean and the hydrosphere covers about 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area (148,000,000 km (57,000,000 sq mi)). The centers of both

10272-504: The southeast of Hawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when

10379-415: The surface of the Pacific Ocean. Multiple islands were the shells of former active volcanoes that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot of atolls that have over intervals of time been formed by seamounts as a result of tiny coral islands strung in a ring within surroundings of a central lagoon . Important human migrations occurred in

10486-478: The temperature and the dew point), mist or fog is reported, depending on the exact visibility. Fog is reported when visibility is 1/2 mile or less; mist is reported for visibilities greater than 0.5 miles (0.80 km) but less than 7 miles (11 km). If the temperature is below freezing , humidity is high and visibility is 1/2 mile or less, freezing fog is reported. Automated airport weather stations use an upward-pointing laser beam ceilometer to detect

10593-804: The tropics and Antarctica, which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with extratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude. The ocean was first mapped by Abraham Ortelius ; he called it Maris Pacifici following Ferdinand Magellan 's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. To Magellan, it seemed much more calm (pacific) than

10700-563: The weather forecast model. A variety of land-based weather station networks have been set up globally. Some of these are basic to analyzing weather fronts and pressure systems, such as the synoptic observation network, while others are more regional in nature, known as mesonets . Automated airport weather station Airport weather stations are automated sensor suites which are designed to serve aviation and meteorological operations, weather forecasting and climatology . Automated airport weather stations have become part of

10807-646: The west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the Bering Strait connects the Pacific with the Arctic Ocean . As the Pacific straddles the 180th meridian , the West Pacific (or western Pacific , near Asia) is in the Eastern Hemisphere , while the East Pacific (or eastern Pacific , near the Americas) is in

10914-534: The width of the Pacific with precision for the first time in history. One of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and

11021-596: The wind speed. The transit time is measured in both directions for several (usually two or three) pairs of the transducer heads. Based on those results, the sensor computes wind speed and direction. Compared to mechanical sensors, the ultrasonic sensors offer several advantages such as no moving parts, advanced self-diagnostic capabilities and reduced maintenance requirements. NWS and FAA ASOS stations and most of new AWOS installations are currently equipped with ultrasonic wind sensors. Unlike all other measurements, which are made between 3 and 9 feet (0.91 and 2.74 meters) above

11128-434: The world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles). Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of seawater, in the poleward areas to about 30 °C (86 °F) near the equator. Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. The water near

11235-575: The world. As with CWOP, each station submitting data to Weather Underground has a unique Web page displaying their submitted data. The UK Met Office 's Weather Observations Website (WOW) also allows such data to be shared and displayed. A weather ship was a ship stationed in the ocean as a platform for surface and upper air meteorological measurements for use in weather forecasting. It was also meant to aid in search and rescue operations and to support transatlantic flights. The establishment of weather ships proved to be so useful during World War II that

11342-583: Was the first to show the Americas separating two distinct oceans. Later, the Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size. (Inhabited dependent territories are denoted by the asterisk (*), with names of the corresponding sovereign states in round brackets. Associated states in the Realm of New Zealand are denoted by the hash sign (#).) Territories with no permanent civilian population. The Pacific Ocean has most of

11449-439: Was the heated tipping bucket rain gauge . The upper portion of this device consists of a 1-foot (0.30 m) diameter collector with an open top. The collector, which is heated to melt any frozen precipitation such as snow or hail , funnels water into a two-chamber, pivoting container called a bucket . Precipitation flows through the funnel into one compartment of the bucket until 0.01-inch (0.25 mm) of water (18.5 grams)

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