Australian region tropical cyclone

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An Australian region tropical cyclone is a non-frontal, low pressure system that has developed, within an environment of warm sea surface temperatures and little vertical wind shear aloft in either the Southern Indian Ocean or the South Pacific Ocean. [1] Within the Southern Hemisphere there are officially three areas where tropical cyclones develop on a regular basis, these areas are the South-West Indian Ocean between Africa and 90°E, the Australian region between 90°E and 160°E and the South Pacific basin between 160°E and 120°W. The Australian region between 90°E and 160°E is officially monitored by the Australian Bureau of Meteorology, the Papua New Guinea National Weather Service and the Indonesian Agency for Meteorology, Climatology and Geophysics, while others like the Fiji Meteorological Service and the United States National Oceanic and Atmospheric Administration also monitor the basin. Each tropical cyclone year within this basin starts on 1 July and runs throughout the year, encompassing the tropical cyclone season which runs from 1 November and lasts until 30 April each season. Within the basin, most tropical cyclones have their origins within the South Pacific Convergence Zone or within the Northern Australian monsoon trough, both of which form an extensive area of cloudiness and are dominant features of the season. Within this region a tropical disturbance is classified as a tropical cyclone, when it has 10-minute sustained wind speeds of more than 65 km/h (35 mph), that wrap halfway around the low level circulation centre, while a severe tropical cyclone is classified when the maximum 10-minute sustained wind speeds are greater than 120 km/h (75 mph).

Weather front boundary separating two masses of air of different densities

A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena outside the tropics. In surface weather analyses, fronts are depicted using various colored triangles and half-circles, depending on the type of front. The air masses separated by a front usually differ in temperature and humidity.

A low-pressure area, low, depression or cyclone is a region on the topographic map where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. The formation process of a low-pressure area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas. The first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies. A second area of wind divergence aloft occurs ahead of embedded shortwave troughs, which are of smaller wavelength. Diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity.

Sea surface temperature Water temperature close to the oceans surface

Sea surface temperature (SST) is the water temperature close to the ocean's surface. The exact meaning of surface varies according to the measurement method used, but it is between 1 millimetre (0.04 in) and 20 metres (70 ft) below the sea surface. Air masses in the Earth's atmosphere are highly modified by sea surface temperatures within a short distance of the shore. Localized areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass. Warm sea surface temperatures are known to be a cause of tropical cyclogenesis over the Earth's oceans. Tropical cyclones can also cause a cool wake, due to turbulent mixing of the upper 30 metres (100 ft) of the ocean. SST changes diurnally, like the air above it, but to a lesser degree. There is less SST variation on breezy days than on calm days. In addition, ocean currents such as the Atlantic Multidecadal Oscillation (AMO), can effect SST's on multi-decadal time scales, a major impact results from the global thermohaline circulation, which affects average SST significantly throughout most of the world's oceans.

Contents

Basin history

There is a history of tropical cyclones affecting northeastern Australia for over 5000 years; however, Clement Lindley Wragge was the first person to monitor and name them. [2]

Clement Lindley Wragge Australian meteorologist

Clement Lindley Wragge was a meteorologist born in Stourbridge, Worcestershire, England, but moved to Oakamoor, Staffordshire as a child. He set up the Wragge Museum in Stafford following a trip around the world. He was a Fellow of the Royal Geographical Society and in 1879 was elected Fellow of the Royal Meteorological Society in London. To the end of his life, he was interested in Theosophy and spiritualism and during his tour of India, met with Mirza Ghulam Ahmad of Qadian, founder of the Ahmadiyya movement in Islam who had claimed to be the Mahdi, the messianic redeemer awaited by Muslims. Sir Arthur Conan Doyle sought him out in New Zealand to ask for his views on spiritualism before writing The Wanderings of a Spiritualist in 1921. After training in law, Wragge became a meteorologist, his accomplishments in the field including winning the Scottish Meteorological Society's Gold Medal and years later starting the trend of using people's names for cyclones. He travelled widely, giving lectures in London and India, and in his later years was an authority on Australia, India and the Pacific Islands.

In the early history of tropical cyclones in the Australian region, the only evidence of a storm was based on ship reports and observations from land. Later, satellite imagery began in the basin in the 1959/60 season, although it was not continuous until 1970. In Western Australia in particular, the lack of population centers, shipping lanes, radars, and offshore stations meant that storms were tracked infrequently. After the onset of satellite imagery, the Dvorak technique was used to estimate storm's intensities and locations. [3]

Dvorak technique

The Dvorak technique is a widely used system to estimate tropical cyclone intensity based solely on visible and infrared satellite images. Within the Dvorak satellite strength estimate for tropical cyclones, there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity. The primary patterns used are curved band pattern (T1.0-T4.5), shear pattern (T1.5–T3.5), central dense overcast (CDO) pattern (T2.5–T5.0), central cold cover (CCC) pattern, banding eye pattern (T4.0–T4.5), and eye pattern (T4.5–T8.0).

Background

The Australian region is currently defined as being between 90E and 160E and is monitored by five different warning centres during the season that runs from 1 November to 30 April. Three of the warning centres are.

Seasons

Before 1967

1967–1969

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
1967–68
1968–69
1969–70 1414114?

1970s

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
1970–71 202010Sheila-SophieUnknown?
1971–72 181810EmilyUnknown?
1972–73 15158Flores1,574>? [4]
1973–74 19199JessieUnknown?
1974–75 16167Tracy71>?
1975–76 16159WatoreaUnknown?
1976–77 13136TedUnknown?
1977–78 952AlbyUnknown?
1978–79 13125HazelUnknown?
1979–80 15159AmyUnknown?

1980s

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
1980–81 141411MabelUnknownUnknown
1981–82 15157Chris-DamiaUnknownUnknown
1982–83 775ElinorUnknownUnknown
1983–84 222111Kathy1$19 Million
1984–85 201811Kristy0$3.5 Million
1985–86 17168Victor153$250 Million
1986–87 972Elsie0None
1987–88 652Gwenda-Ezenina1$17.9 Million
1988–89 14136Orson6$93.9 Million
1989–90 14144AlexUnknownUnknown

1990s

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
1990–91 12107Marian27
1991–92 12109Harriet-Heather5
1992–93 884Oliver0
1993–94 14127Theodore22
1994–95 1966Chloe1
1995–96 19159Olivia1
1996–97 17155Pancho34
1997–98 1194Tiffany [5]
1998–99 21149Gwenda8 [5]
1999-00 14125John/Paul0 [5]

2000s

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
2000–01 983Sam2 [5]
2001–02 14104Chris19 [5]
2002–03 1183Inigo62 [5]
2003–04 13105Fay0 [5]
2004–05 13104Ingrid5 [5]
2005–06 18149Glenda1 [5]
2006–07 853George3 [5]
2007–08 1493Pancho149 [5]
2008–09 24113Hamish5 [5]
2009–10 1384Laurence3 [5]

2010s

SeasonTropical
Lows
Tropical
Cyclones
Severe Tropical
Cyclones
Strongest
storm
DeathsDamagesReferences
2010–11 28115Yasi3 [5] [6]
2011–12 2172Lua16> [6]
2012–13 16104Narelle20 [7]
2013–14 17105Ita22
2014–15 1897Marcia1>
2015–16 1130Stan0None [A 1]
2016–17 3093Ernie16
2017–18 23113Marcus41
2018-19 25116Veronica14

Notes

  1. Number of tropical lows and tropical cyclones excludes Tropical Cyclone Raquel, which was considered to have been a part of the 2014-15 year. [8]

See also

Tropical cyclone Is a rotating storm system

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".

Atlantic hurricane season tropical cyclone season

The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean. Tropical cyclones in the North Atlantic are called hurricanes, tropical storms, or tropical depressions. In addition, there have been several storms over the years that have not been fully tropical and are categorized as subtropical depressions and subtropical storms. Even though subtropical storms and subtropical depressions are not technically as strong as tropical cyclones, the damages can still be devastating.

South Atlantic tropical cyclone unusual weather event originating in the South Atlantic Ocean

South Atlantic tropical cyclones are unusual weather events that occur in the Southern Hemisphere. Strong wind shear, which disrupts the formation of cyclones, as well as a lack of weather disturbances favorable for development in the South Atlantic Ocean make any strong tropical system extremely rare, and Hurricane Catarina in 2004 is the only recorded South Atlantic hurricane in history. South Atlantic storms have developed year-round, with activity peaking during the months from November through May in this basin. Since 2011, the Brazilian Navy Hydrographic Center has assigned names to tropical and subtropical systems in the western side of the basin, near Brazil, when they have sustained wind speeds of at least 65 km/h (40 mph), the generally accepted minimum sustained wind speed for a disturbance to be designated as a tropical storm in the North Atlantic basin. Below is a list of notable South Atlantic tropical and subtropical cyclones.

Related Research Articles

Tropical cyclones and subtropical cyclones are named by various warning centers to provide ease of communication between forecasters and the general public regarding forecasts, watches, and warnings. The names are intended to reduce confusion in the event of concurrent storms in the same basin. Generally once storms produce sustained wind speeds of more than 33 knots, names are assigned in order from predetermined lists depending on which basin they originate. However, standards vary from basin to basin: some tropical depressions are named in the Western Pacific, while tropical cyclones must have a significant amount of gale-force winds occurring around the centre before they are named in the Southern Hemisphere.

Tropical cyclones are ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.

Tropical cyclone basins area of tropical cyclone formation

Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.

2003–04 South Pacific cyclone season cyclone season in the South Pacific ocean

The 2003–04 South Pacific cyclone season was a below-average season with only three tropical cyclones occurring within the South Pacific to the east of 160°E. The season officially ran from November 1, 2003 to April 30, 2004 with the first disturbance of the season forming on December 4 and the last disturbance dissipating on April 23. This is the period of the year when most tropical cyclones form within the South Pacific Ocean.

A South Pacific tropical cyclone is a non frontal, low pressure system that has developed, within an environment of warm sea surface temperatures and little vertical wind shear aloft in the South Pacific Ocean. Within the Southern Hemisphere there are officially three areas where tropical cyclones develop on a regular basis, these areas are the South-West Indian Ocean between Africa and 90°E, the Australian region between 90°E and 160°E and the South Pacific basin between 160°E and 120°W. The South Pacific basin between 160°E and 120°W is officially monitored by the Fiji Meteorological Service and New Zealand's MetService, while others like the Australian Bureau of Meteorology and the United States National Oceanic and Atmospheric Administration also monitor the basin. Each tropical cyclone year within this basin starts on July 1 and runs throughout the year, encompassing the tropical cyclone season which runs from November 1 and lasts until April 30 each season. Within the basin, most tropical cyclones have their origins within the South Pacific Convergence Zone or within the Northern Australian monsoon trough, both of which form an extensive area of cloudiness and are dominant features of the season. Within this region a tropical disturbance is classified as a tropical cyclone, when it has 10-minute sustained wind speeds of more than 65 km/h (35 mph), that wrap halfway around the low level circulation centre, while a severe tropical cyclone is classified when the maximum 10-minute sustained wind speeds are greater than 120 km/h (75 mph).

South-West Indian Ocean tropical cyclone type of tropical cyclone located in South West Indian Ocean and measured by Météo-France La Reunion scale

In the south-west Indian Ocean, tropical cyclones form south of the equator and west of 90° E to the coast of Africa.

2010–11 Australian region cyclone season cyclone season in the Australian region

The 2010–11 Australian region cyclone season was a near average tropical cyclone season, with eleven tropical cyclones forming compared to an average of 12. The season was also the costliest recorded in the Australian region basin, with a total of $3.62 billion in damages, mostly from the destructive Cyclone Yasi. The season began on 1 November 2010 and ended on 30 April 2011, although the first tropical cyclone formed on 28 October. The Australian region is defined as being to the south of the equator, between the 90th meridian east and 160th meridian east. Tropical cyclones in this area are monitored by five Tropical Cyclone Warning Centres (TCWC's): Jakarta, Port Moresby, Perth, Darwin, and Brisbane, each of which have the power to name a tropical cyclone. The TCWC's in Perth, Darwin, and Brisbane are run by the Bureau of Meteorology, who designate significant tropical lows with a number and the U suffix. The Joint Typhoon Warning Center also issues unofficial warnings for the region, designating significant tropical cyclones with the "S" suffix when they form west of 135°E, and the "P" suffix when they form east of 135°E.

1988–89 Australian region cyclone season cyclone season in the Australian region

The 1988–89 Australian region cyclone season was a slightly above average tropical cyclone season. It officially started on 1 November 1988, and officially ended on 30 April 1989. The regional tropical cyclone operational plan defines a "tropical cyclone year" separately from a "tropical cyclone season"; the "tropical cyclone year" began on 1 July 1988 and ended on 30 June 1989.

1990–91 South Pacific cyclone season cyclone season in the South Pacific ocean

The 1990–91 South Pacific cyclone season was one of the least active cyclone seasons, with only three tropical cyclones occurring within the South Pacific basin which is to the east of 160°E. The season officially ran from November 1, 1990, to April 30, 1991, with the first disturbance of the season forming on November 23 and the last disturbance dissipating on May 19. This is the period of the year when most tropical cyclones form within the South Pacific Ocean. During the season there was no deaths recorded from any of the tropical cyclones while they were within the basin. However six people were killed by Cyclone Joy, when it made landfall on Australia. As a result of the impacts caused by Joy and Sina, the names were retired from the tropical cyclone naming lists.

Cyclone Katrina Category 4 Australian region, South Pacific, and South-West Indian cyclone in 1998

Severe Tropical Cyclone Katrina was a long-lived and erratic tropical cyclone, which moved around Australia during parts of January and February 1998. The initial system developed on 2 January and meandered within the Coral Sea between the Queensland coast and Vanuatu for the next three weeks. After its decay the remnants of Katrina moved westward over Cape York Peninsula, past the Northern Territory and into the Indian Ocean.

2014–15 Australian region cyclone season

The 2014–15 Australian region cyclone season was a slightly below average tropical cyclone season. The season officially ran from 1 November 2014, to 30 April 2015, however, a tropical cyclone could form at any time between 1 July 2014, and 30 June 2015, and would count towards the season total. During the season, tropical cyclones were officially monitored, by one of the five Tropical Cyclone Warning Centres (TCWCs) that are operated in this region.

2014–15 South Pacific cyclone season

The 2014–15 South Pacific cyclone season was a slightly-below average tropical cyclone season, with five tropical cyclones occurring within the basin between 160°E and 120°W. The season officially ran from November 1, 2014 to April 30, 2015. During the season, tropical cyclones were officially monitored by the Regional Specialized Meteorological Center (RSMC) in Nadi, Fiji and the Tropical Cyclone Warning Centers in Brisbane, Australia and Wellington, New Zealand. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) also monitored the basin and issued unofficial warnings for American interests. RSMC Nadi attaches a number and an F suffix to tropical disturbances that form in or move into the basin while the JTWC designates significant tropical cyclones with a number and a P suffix. RSMC Nadi, TCWC Wellington and TCWC Brisbane all use the Australian Tropical Cyclone Intensity Scale and estimate windspeeds over a period of ten minutes, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

1985–86 South Pacific cyclone season cyclone season in the South Pacific ocean

The 1985–86 South Pacific cyclone season was an average tropical cyclone season, in terms of tropical cyclone formation, with ten tropical cyclones occurring within the basin between 160°E and 120°W. The season ran from February 5, 1985, to May 22, 1986, with tropical cyclones officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService. The United States Joint Typhoon Warning Center (JTWC) and other national meteorological services including Météo-France and NOAA also monitored the basin during the season. During the season there was nine tropical cyclones occurring within the basin, including three that moved into the basin from the Australian region.

2015–16 South Pacific cyclone season

The 2015–16 South Pacific cyclone season was one of the most disastrous South Pacific tropical cyclone seasons on record, with a total of 50 deaths and $1.405 billion in damage. Throughout the season, 8 systems attained tropical cyclone status, whilst 5 became severe tropical cyclones. The most notable cyclone of the season by far was Winston, which attained a minimum pressure of 884 hPa, and maximum ten-minute sustained winds of 175 mph (280 km/h), making it the most intense tropical cyclone on record in the Southern Hemisphere. Winston went on to devastate Fiji, causing $1.4 billion in damage and 44 deaths across the country.

Tropical cyclones in 2015

Tropical cyclones in 2015 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Hurricane Patricia, which strengthened to a minimum barometric pressure of 872 mbar before striking the east coast of Colima in Mexico. 133 tropical cyclones had formed this year to date. 92 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC).

Tropical cyclones in 2019 are spread out across seven different areas called basins and the Mediterranean Sea. Currently, 45 systems have formed during the year to date. 27 tropical cyclones have been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC).

Tropical cyclones in 2014

Tropical cyclones in 2014 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Typhoon Vongfong, which strengthened to a minimum barometric pressure of 900 mbar before striking the east coast of Japan. 119 tropical cyclones had formed this year to date. 82 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2014 was the Western Pacific, which documented 23 named systems, while the Eastern Pacific, despite only amounting to 22 named systems, was its basin's most active since 1992. Conversely, both the North Atlantic hurricane and North Indian Ocean cyclone seasons experienced the least number of cyclones reaching tropical storm intensity in recorded history, numbering 9 and 3, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece.

Tropical cyclones in 2004 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Cyclone Gafilo, which strengthened to a minimum barometric pressure of 895 mbar becomes the most intense tropical cyclone ever recorded in the South-West Indian Ocean before striking the east coast of Madagascar. 130 tropical cyclones had formed this year to date. 81 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2004 was the Western Pacific, which documented 29 named systems, while the North Atlantic, despite only amounting to 15 named systems, was its basin's hyperactive season since 1995. Conversely, both the Eastern Pacific hurricane and North Indian Ocean cyclone seasons experienced the least number of cyclones reaching tropical storm intensity in recorded history, numbering 12 and 4, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece.

Tropical cyclones in 2012

Tropical cyclones in 2012 were spread out across seven different areas called basins; the strongest tropical cyclone was Typhoon Sanba strengthened to a minimum barometric pressure of 900 mbar before striking South Korea. 132 tropical cyclones had formed this year to date. 88 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in the year was the Western Pacific, which documented 25 named systems, while the North Atlantic Pacific, despite only amounting to 19 named systems, was its basin's hyperactive since 2010 becoming the third-most active season on record. Conversely, the Eastern Pacific hurricane season experienced the average number of cyclones reaching tropical storm intensity, numbering 17 respectively. The least tropical cyclone season was North Indian Ocean had a late start, with the first system forming in October. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece.

References

  1. RA V Tropical Cyclone Committee (5 May 2015). List of Tropical Cyclone Names withdrawn from use due to a Cyclone's Negative Impact on one or more countries (PDF) (Tropical Cyclone Operational Plan for the South-East Indian Ocean and the Southern Pacific Ocean 2014). World Meteorological Organization. pp. 2B–1–2B–4 (23–26). Archived (PDF) from the original on 24 May 2015. Retrieved 6 May 2015.
  2. Nott, Jonathon (14 November 2003). "Palaeotempestology: the study of prehistoric tropical cyclones—a review and implications for hazard assessment". Science Direct. Retrieved 14 September 2015.
  3. S.J. Buchan; P.G. Black; R.L. Cohen (1999). The Impact of Tropical Cyclone Olivia on Australia's Northwest Shelf (PDF). Offshore Technology Conference. Retrieved 14 January 2016.
  4. http://www.typhoon2000.ph/garyp_mgtcs/dec01.txt
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Padgett, Gary (1997–2011). "Monthly Global Tropical Cyclone Summaries". Archived from the original on 2011. Retrieved 19 February 2012.
  6. 1 2 National Climate Centre (3 July 2012). "Record-breaking La Niña events – Tropical cyclone activity during 2010–11 and 2011–12" (PDF). Australian Bureau of Meteorology. p. 17. Archived from the original (PDF) on 22 July 2012. Retrieved 22 July 2012.
  7. Nathan Paull and Miranda Forster (29 January 2013). "Floods recede as states count cost". Australian Associated Press. News Limited. Retrieved 29 January 2013.
  8. Queensland Regional Office (September 2015). Tropical Cyclone Raquel (Report). Australian Bureau of Meteorology. Retrieved 15 September 2015.