Typhoon
A typhoon is a tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere and which produces sustained hurricane-force winds of at least 119 km/h (74 mph).
For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern (North America to 140°W), central (140°W to 180°), and western (180° to 100°E).
Southern China has the longest record of typhoon impacts for the region, with a thousand-year sample via documents within their archives.
[8] The usage of 颱風 was not dominant until Chu Coching, the head of meteorology of the national academy from 1929 to 1936, declared it to be the standard term.
[13] This claim contradicts the fact that the Cantonese term for typhoon was 風舊 [fuŋ kɐu] before the national promotion of 颱風.
[8] 風舊 (meaning "winds which long last") was first attested in 280, being the oldest Chinese term for typhoon.
[10][11] On the other hand, Chinese records consistently assert foreigners refer typhoon as "black wind".
[10][11] "Black wind" eventually enters the vocabulary of Jin Chinese as 黑老風 [xəʔ lo fəŋ].
[14] Alternatively, some dictionaries propose that typhoon derived from (طوفان) tūfān, meaning storm in Persian and Hindustani.
As a result, the JTWC's wind reports are higher than JMA's measurements, as the latter is based on a 10-minute averaging interval.
Normally, an ocean temperature of 26.5 °C (79.7 °F) spanning through a depth of at least 50 metres (160 ft) is considered the minimum to maintain the special mesocyclone that is the tropical cyclone.
Vertical wind shear of less than 10 m/s (20 kn, 33 ft/s) between the ocean surface and the tropopause is required for tropical cyclone development.
[23][25] Typically with Pacific typhoons, there are two jets of outflow: one to the north ahead of an upper trough in the westerlies, and a second towards the equator.
As the oscillation propagates from west to east, it leads to an eastward march in tropical cyclogenesis with time during that hemisphere's summer season.
[31] The most frequently impacted areas of the Philippines by tropical cyclones are northern and central Luzon and eastern Visayas.
[33] The genesis and intensity of typhoons are also modulated by slow variation of the sea surface temperature and circulation features following a near-10-year frequency.
Areas west of Japan and Korea tend to experience many fewer September–November tropical cyclone impacts during El Niño and neutral years.
During El Niño years, the break in the subtropical ridge tends to lie near 130°E, which would favor the Japanese archipelago.
[37] During La Niña years, the formation of tropical cyclones, and the subtropical ridge position, shift westward across the western Pacific Ocean, which increases the landfall threat to China and greater intensity to Philippines.
[20] However each National Meteorological and Hydrological Service within the western Pacific has the responsibility for issuing warnings for land areas about tropical cyclones affecting their country, such as the Joint Typhoon Warning Center for United States agencies,[40] the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) for interests in the island archipelago nation,[41] and the Hong Kong Observatory for storms that come close enough to cause the issuance of warning signals.
[42] The list of names consists of entries from 14 southeast and east Asian nations and regions and the United States who have territories directly affected by typhoons.
[44] Storms that cross the date line from the central Pacific retain their original name, but the designation of hurricane becomes typhoon.
