Nomenclature of the tropical cyclones
This article treats Nomenclature of the tropical cyclones , that is to say the names which the various phases in the life of the tropical cyclones take. One also milked there terms associated with the subtropical and extratropicaux cyclones which can be at the origin or the dissipation of the tropical cyclones. Finally, one gives the list of the names of storms planned for the next cyclone seasons.
Phases of life of a tropical cyclone
See also: Cyclogénèse tropical
A tropical wave is a curve in the normally right flow of the air of surface under the Tropique S, in the form of a barometric Creux. When accompanied by Downpour S and Storm S, one rather speaks about tropical disturbance .
The tropical waves occur in the Zone of intertropical convergence (ZCIT), a belt of low pressures encircling the Ground near the equator. They move under the influence of the winds Alizé S, towards the west in the northern Hemisphere, towards the east in the Southern hemisphere. A tropical wave which moves too quickly cannot produce cyclonic circulation necessary to the production of tropical storms. However, such a tropical wave often generates winds of tropical storm on its wake.
Atlantic OceanIn the Atlantic Ocean, a tropical wave typical appears in West Africa, and moves towards the west. Approximately 60% of the tropical cyclones of the basin of the Atlantic come from tropical waves. It also happens that tropical cyclones degenerate into tropical waves.
Is Pacific OceanThe majority of the tropical waves of the east of the Pacific Ocean are tropical waves of the Atlantic Ocean which migrated through the Central America.
See also: Cyclogénèse tropical
A tropical disturbance is a weather system having the following characteristics:
- presence of more or less organized clouds convectif S;
- covers large a Superficie, in general from 200 to 600 km of Diamètre (100 to 300 nautical miles);
- presence of a zone of low pressures little marked;
- absence of weather faces;
- appearance of a cyclonic circulation of the Wind S of Surface;
- Lasted of a Day (24 hour S) or more.
A tropical disturbance whose Vent S of surface follow a detectable cyclonic circulation is called tropical depression .
See also: Cyclogénèse tropical
A tropical depression is a tropical disturbance which has the following characteristics:
- the presence of a depression, distinguishable on the chart of the isobars by a closed circle;
- the winds of surface turn cycloniquement (anti-clockwise direction in the Northern Hemisphere, time direction in the Southern hemisphere) around the depressionary center;
- the maximum of the average Speed of the Vent S supported during a minute is to the maximum of 17 meters a second (see table).
See also: Cyclogénèse tropical
A tropical storm is a tropical depression which has the following characteristics:
- the maximum of the average Speed of the Vent S supported during a minute is higher than 17 meters a second and lower than 33 meters a second (see table);
- close to the coasts, it can be accompanied by a Onde of storm up to 1,2 Mètre S (locally, this effect can be accentuated by the Hydrographie of the places and the fluctuations of the Marée S).
If a tropical storm has suddenly accumulated sufficient energy, it will be able to generate constant winds of more than 33 m/s and will be regarded as a tropical Cyclone. One will be able to then observe, most of the time, a zone cleared in the center of the cyclone, the eye. Dependently cyclonic basin where it is placed, one will assign to him the name of hurricane, typhoon, or cyclone.
See also: tropical Cyclone, Cyclogénèse tropical
A tropical cyclone is the evolution of a tropical storm and has the following characteristics:
- the maximum of the average Speed of the Vent S supported during a minute is higher than 33 meters a second;
- close to the coasts, one observes a wave of storm of at least 1,2 Mètre S (locally, this effect can be accentuated by the Hydrographie of the places and the fluctuations of the Marée S).
Various denominations are given to the tropical cyclones, according to the cyclonic basin where they prevail:
- Hurricane : Atlantic Ocean Northern and Pacific Ocean Northern in the east of the Date-line;
- Typhoon : Pacific Ocean Northern in the west of the Date-line;
- tropical Cyclone violates : Pacific Ocean Southern in the west of 160°E and Indian Ocean Southern in the east of 90°E;
- cyclonic Tempête forces : Indian Ocean Northern;
- tropical Cyclone : Indian Ocean Southern in the west of 90°E and Pacific Ocean Southern in the east of 160°E;
- Cyclone : Atlantic Ocean Southern (semi-official formulation).
- Bagyo : Filipino;
- Taino : Haiti;
- the term Willy-willy , often found in the literature like a local term in Australia, is erroneous because it indicates in fact a Swirl of dust,
The force of the cyclones is classified by the scale of Saffir-Simpson energy of 1 with 5 :
- Definitions according to the Weather service of Canada and the National Weather American Service
- Wave of storm: raising of the sea level due to the winds and the pressure of the cyclone. She is added to the level of the regular tide along the coasts when such a system approaches some.
Major hurricaneA major hurricane is a term used by the National Hurricane Center to indicate a hurricane whose constant winds exceed the 50 m/s, that is to say hurricane forces 3 or more on the scale of Saffir-Simpson.
See also: Hurricane capverdien
A hurricane capverdien is a hurricane which one can recall the origin near the islands of the Cape Verde (1000 km with the round), close to the West Africa, and who becomes hurricane above the Atlantic Ocean.
See also: subtropical Cyclone
A subtropical storm is a system low pressures developing halfway between the Tropique S and the Latitude S averages, and which has certain characteristics of the tropical storms. If the conditions arise, a subtropical storm can become tropical.
See also: Cyclone extratropical
A storm extratropicale or cyclone extratropical is a depression of the average latitudes whose primary source of energy is in the differences of Atmospheric pressure. The vertical shearing of the winds is significant there and the distribution of heat and moisture is very asymmetrical compared to the center of the system.
Lists of names of the tropical cyclones by basin
NorthSince 1979, the tropical cyclones are baptized with first names alternatively male and female. The first names are first names in English, Spanish and French. A principle of cycles was also established. Based on 6 years and six lists, the even years begin with a male first name and odd a female first name. Thus the list of 2000 is the same one as that of 1994; the list of 2001 shows those of 1989 and 1995. At the time of serious cyclones, the names of the latter are removed list and are replaced in order not to shock the population by pointing out too bad memories to him.
The six lists lay down 21 current first names of has with W but without Q nor U , rather low in first names. Then, it is envisaged to use the Greek letters. In 2005, year of record with 27 cyclones, the list was completely used until Wilma, then to the Greek letter Zêta.
SouthThe tropical cyclones are very rare in the south of Ecuador in the Atlantic Ocean. There is thus no list designed to name them. When a ourgan occurred there in 2004, it took the name of Cyclone Catarina according to the place where it touched ground, that is to say Santa Catarina with the Brésil. Some Meteorologist S one however called hurricane Aldonça by using the same idea that in the North Atlantic, that is to say by a name beginning in has .
The northern Pacific
In the east of 140 WestThe tropical names of the cyclone in this sector of the Pacific follow a design identical to that of the North Atlantic but with its own list. The first lists of names were introduced one year before those into the Atlantic, that is to say in 1978. One finds six lists which are used in rotation but only two lists contain names with X, Y and Z with the result that the portion with these names is repeated at each two years. It is only starting from 1985 that these names starting with X, Y and Z were added whereas the number of hurricanes seemed to want to exceed the original lists. In 1978, one used list IV then rotation started again with list I.
The names of hurricanes can be withdrawn from the list in consequence of exceptional damage but that seldom occurs since the trajectory of the systems in north-eastern Pacific is generally above the sea. To be withdrawn last is the Ouragan Kenna in 2002. As in the North Atlantic, the Greek alphabet (Alpha, Beta, etc) would be used so more than 24 storms occurred.
Center-north (Date-line to 140 West)In the center-north of the Pacific Ocean, the tropical cyclones are named by the Central Pacific Hurricane Center American, located at Honolulu, Hawaii. The four lists go according to the order of the alphabet hawaiien. The names are used one after the other until exhaustion of the current list then one passes to the following list. For example, the last cyclone of 2006 was Ioke , withdrawn because of its effects and will be replaced by Iopa , and the first of 2007 will be Kika . Thus the lists are not annual.
The North-WestThe cyclones of the North-western Pacific are named by the center of the typhoons of Tokyo of the Japanese meteorological agency. They are drawn from the lists below which were made according to the recommendations of the members of the committee on the typhoons of the world meterologic Organization. These fourteen nations or territories, which are in the basin of the North-western Pacific Ocean, subjected each one ten names which are not necessarily first names and are not it alphabetically. The names in fact are used sequentially according to the alphabetical order of the name of the country tenderer in the English language and not in that of the names them-even. Thus Tenbin is followed of Bolaven because Japan is followed of Laos.
While following these bonds, one finds the direction of the names suggested by HongKong and the other countries.
PhilippinesThe Administration of the atmospheric services, geophysics and astronomoque of Philippines, PAGASA , uses its own lists to name the tropical depressions, storms and cyclones inside its zone of resposability. These names are used in parallel with those of the committee of the OMM mentioned previously. There are four lists used in annual rotation. If the number of typhoons to be occurred is higher than the number of names on the list for one year, the following names are taken of an auxiliary list. The order of use started again with the list I in 2005.
NorthThis list is in force half of 2004 up to 2009. The names will be used sequentially without repetition.
South-westThe weather center of the Mauritius gives the names to the cyclones which are formed or entered the Indian Ocean to the west of the 90 East degrees and the south of the Ecuador. The cyclones which come from the Australian zone thus receive a new name while entering this sector. The lists of names are made in a way similar to that of the North Atlantic and of Pacific Is but the period of validity is not annual because of the southern season of the tropical cyclones. It thus goes from one year July to June of the following year. The lists are remade after a few years and are not cyclic like those above mentioned.
AustraliaThe Office off Meteorology autralien gives different names according to the coast where they occur. The lists function in a way similar to that of the sector hawaiien, i.e. the names are used sequentially in a list then in the following one without taking account of the year. The cyclones having caused damage out of ordinary will be withdrawn and their position in the corresponding list will be taken by a new name.
West (90E with 125 E)
North (125E with 137E)
Is (137E with 160E, south of ~10S)
The southern Pacific
FijiThe names chosen for the tropical cyclones of the Pacific passing in the sector of the Islands Fiji (of the 160°E with 120°O in the south of Ecuador) are found on four lists used in rotation ( has, B, C and D ). A list E is used for the replacement of withdrawn names.
New Guinea-News-GuineaFor the cyclones of the Pacific passing by the New Guinea-News-Guinea (of the 140°E to the 160°E, in the north of the 10°S), the list has is used sequentially since 2005 . One starts again at the beginning of the list with each year but if the number of cyclones exceeds the number of names of this list, one passes to the list B by concern of following the alphabetical order.
- Fair with the questions about the tropical cyclones by [[Weather-France] in New Caledonia]
- Lists of the names by [[Weather-France] in New Caledonia]
- Lists of names of the more up to date cyclones by [[the National Hurricane Center] American]
- Same lists of [[Met Office] British] the
- Article of newspaper in connection with the origin of the names of tropical cyclones
- Lists of [[Office off Meteorology] Australian for its zone of responsibility] the
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