Tropical cycloneFrom Wikipedia, the free encyclopedia

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A tropical cyclone is a storm systemcharacterized by a large low-pressure center and

numerous thunderstorms that produce strong winds and heavy rain. Tropicalcyclones strengthen when water

evaporated from the ocean is released as the saturatedair rises, resulting in condensation of water

vapor contained in the moist air. They are fueled by a different heat mechanism than other cyclonic windstorms

such asnor'easters, European windstorms, and polar lows. The characteristic that separates tropical cyclones

from other cyclonic systems is that at any height in the atmosphere, the center of a tropical cyclone will be

warmer than its surroundings; a phenomenon called "warm core" storm systems.

The term "tropical" refers both to the geographical origin of these systems, which usually form

in tropical regions of the globe, and to their formation in maritime tropical air masses. The term "cyclone" refers

to such storms' cyclonic nature, with counterclockwise wind flow in the Northern Hemisphere and clockwise

wind flow in theSouthern Hemisphere. The opposite direction of the wind flow is a result of the Coriolis force.

Depending on its location and strength, a tropical cyclone is referred to by names such

as hurricane (/ˈhʌrɨkeɪn/, /ˈhʌrɨkən/), typhoon, tropical storm, cyclonic storm,tropical depression, and

simply cyclone.

While tropical cyclones can produce extremely powerful winds and torrential rain, they are also able to produce

high waves and damaging storm surge as well as spawning tornadoes. They develop over large bodies of

warm water, and lose their strength if they move over land due to increased surface friction and loss of the

warm ocean as an energy source. This is why coastal regions can receive significant damage from a tropical

cyclone, while inland regions are relatively safe from receiving strong winds. Heavy rains, however, can

produce significant flooding inland, and storm surges can produce extensive coastal flooding up to 40

kilometres (25 mi) from the coastline. Although their effects on human populations can be devastating, tropical

cyclones can relieve drought conditions. They also carry heat energy away from the tropics and transport it

toward temperate latitudes, which makes them an important part of the global atmospheric

circulation mechanism. As a result, tropical cyclones help to maintain equilibrium in the Earth's troposphere,

and to maintain a relatively stable and warm temperature worldwide.

Many tropical cyclones develop when the atmospheric conditions around a weak disturbance in the

atmosphere are favorable. The background environment is modulated by climatological cycles and patterns

such as the Madden-Julian oscillation, El Niño-Southern Oscillation, and the Atlantic multidecadal oscillation.

Others form when other types of cyclones acquire tropical characteristics. Tropical systems are then moved

by steering winds in the troposphere; if the conditions remain favorable, the tropical disturbance intensifies, and

can even develop an eye. On the other end of the spectrum, if the conditions around the system deteriorate or

the tropical cyclone makes landfall, the system weakens and eventually dissipates. It is not possible to

artificially induce the dissipation of these systems with current technology.

Part of a series on

Tropical cyclones

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Contents

  [hide] 

1 Physical structure

o 1.1 Eye and center

o 1.2 Size

2 Mechanics

3 Major basins and related warning centers

4 Formation

o 4.1 Times

o 4.2 Factors

o 4.3 Locations

5 Movement and track

o 5.1 Steering winds

o 5.2 Coriolis effect

o 5.3 Interaction with the mid-latitude westerlies

o 5.4 Landfall

o 5.5 Multiple storm interaction

6 Dissipation

o 6.1 Factors

o 6.2 Artificial dissipation

7 Effects

8 Observation and forecasting

o 8.1 Observation

o 8.2 Forecasting

9 Classifications, terminology, and naming

o 9.1 Intensity classifications

9.1.1 Tropical depression

9.1.2 Tropical storm

9.1.3 Hurricane or typhoon

o 9.2 Origin of storm terms

o 9.3 Naming

10 Notable tropical cyclones

11 Changes caused by El Niño-Southern Oscillation

12 Long-term activity trends

13 Global warming

14 Related cyclone types

15 Tropical cyclones in popular culture

16 See also

17 References

18 External links

[edit]Physical structure

See also: Eye (cyclone)

All tropical cyclones are areas of low atmospheric pressure in the Earth's atmosphere. The pressures recorded

at the centers of tropical cyclones are among the lowest that occur on Earth's surface at sea level.[1] Tropical

cyclones are characterized and driven by the release of large amounts of latent heat of condensation, which

occurs when moist air is carried upwards and its water vapor condenses. This heat is distributed vertically

around the center of the storm. Thus, at any given altitude (except close to the surface, where water

temperature dictates air temperature) the environment inside the cyclone is warmer than its outer surroundings.[2]

[edit]Eye and center

A strong tropical cyclone will harbor an area of sinking air at the center of circulation. If this area is strong

enough, it can develop into a large "eye". Weather in the eye is normally calm and free of clouds, although the

sea may be extremely violent.[3] The eye is normally circular in shape, and is typically 30–65 km (19–40 miles)

in diameter, though eyes as small as 3 kilometres (1.9 mi) and as large as 370 kilometres (230 mi) have been

observed.[4][5] Intense, mature tropical cyclones can sometimes exhibit an outward curving of the eyewall's top,

making it resemble an arena football stadium; this phenomenon is thus sometimes referred to as the stadium

effect.[6] It is usually coldest in the center.

There are other features that either surround the eye, or cover it. The central dense overcast is the

concentrated area of strong thunderstorm activity near the center of a tropical cyclone;[7] in weaker tropical

cyclones, the CDO may cover the center completely.[8] The eyewall is a circle of strong thunderstorms that

surrounds the eye; here is where the greatest wind speeds are found, where clouds reach the highest, and

precipitation is the heaviest. The heaviest wind damage occurs where a tropical cyclone's eyewall passes over

land.[3] Eyewall replacement cycles occur naturally in intense tropical cyclones. When cyclones reach peak

intensity they usually have an eyewall and radius of maximum winds that contract to a very small size, around

10 to 25 kilometres (6.2 to 16 mi). Outer rainbands can organize into an outer ring of thunderstorms that slowly

moves inward and robs the inner eyewall of its needed moisture and angular momentum. When the inner

eyewall weakens, the tropical cyclone weakens (in other words, the maximum sustained winds weaken and the

central pressure rises.) The outer eyewall replaces the inner one completely at the end of the cycle. The storm

can be of the same intensity as it was previously or even stronger after the eyewall replacement cycle finishes.

The storm may strengthen again as it builds a new outer ring for the next eyewall replacement. [9]

Size descriptions of tropical cyclones

ROCI Type

Less than 2 degrees latitude Very small/midget

2 to 3 degrees of latitude Small

3 to 6 degrees of latitude Medium/Average

6 to 8 degrees of latitude Large

Over 8 degrees of latitude Very large[10]

[edit]Size

One measure of the size of a tropical cyclone is determined by measuring the distance from its center of

circulation to its outermost closed isobar, also known as its ROCI. If the radius is less than twodegrees of

latitude or 222 kilometres (138 mi), then the cyclone is "very small" or a "midget". A radius between 3 and

6 latitude degrees or 333 to 670 kilometres (207 to 420 mi) are considered "average-sized". "Very large"

tropical cyclones have a radius of greater than 8 degrees or 888 kilometres (552 mi).[10] Use of this measure

has objectively determined that tropical cyclones in the northwest Pacific Ocean are the largest on earth on

average, with Atlantic tropical cyclones roughly half their size.[11] Other methods of determining a tropical

cyclone's size include measuring the radius of gale force winds and measuring the radius at which its

relative vorticityfield decreases to 1×10−5 s−1 from its center.[12][13]

[edit]Mechanics

Tropical cyclones form when the energy released by the condensation of moisture in rising air causes a positive feedback

loop over warm ocean waters.[14]

A tropical cyclone's primary energy source is the release of the heat of condensation from water

vaporcondensing, with solar heating being the initial source for evaporation. Therefore, a tropical cyclone can

be visualized as a giant vertical heat engine supported by mechanics driven by physical forces such as

therotation and gravity of the Earth.[15] In another way, tropical cyclones could be viewed as a special type

ofmesoscale convective complex, which continues to develop over a vast source of relative warmth and

moisture. While an initial warm core system, such as an organized thunderstorm complex, is necessary for the

formation of a tropical cyclone, a large flux of energy is needed to lower atmospheric pressuremore than a few

millibars (0.10 inch of mercury). The inflow of warmth and moisture from the underlying ocean surface is critical

for tropical cyclone strengthening.[16] A significant amount of the inflow in the cyclone is in the lowest 1 kilometre

(3,300 ft) of the atmosphere.[17]

Condensation leads to higher wind speeds, as a tiny fraction of the released energy is converted into

mechanical energy;[18] the faster winds and lower pressure associated with them in turn cause increased

surface evaporation and thus even more condensation. Much of the released energy drivesupdrafts that

increase the height of the storm clouds, speeding up condensation.[19] This positive feedback loop, called

the Wind-induced surface heat exchange, continues for as long as conditions are favorable for tropical cyclone

development. Factors such as a continued lack of equilibrium in air mass distribution would also give

supporting energy to the cyclone. The rotation of the Earth causes the system to spin, an effect known as

the Coriolis effect, giving it a cyclonic characteristic and affecting the trajectory of the storm.[20][21][22] In

the Northern Hemisphere, where the cyclone's wind flow is counterclockwise, the fastest winds relative to the

surface of the Earth occur on the eastern side of a northward-moving storm and on the northern side of a

westward-moving one; the opposite occurs in the Southern Hemisphere, where the wind flow is clockwise.[23]

What primarily distinguishes tropical cyclones from other meteorological phenomena is deep convection as a

driving force.[24] Because convection is strongest in a tropical climate, it defines the initial domain of the tropical

cyclone. By contrast, mid-latitude cyclones draw their energy mostly from pre-existing horizontal

temperature gradients in the atmosphere.[24] To continue to drive its heat engine, a tropical cyclone must remain

over warm water, which provides the needed atmospheric moisture to keep the positive feedback loop running.

When a tropical cyclone passes over land, it is cut off from its heat source and its strength diminishes rapidly. [25]

Chart displaying the drop in surface temperature in the Gulf of Mexico as HurricanesKatrina and Rita passed over

The passage of a tropical cyclone over the ocean causes the upper layers of the ocean to cool substantially,

which can influence subsequent cyclone development. This cooling is primarily caused by wind-driven mixing

of cold water from deeper in the ocean and the warm surface waters. This effect results in a negative feedback

process that can inhibit further development or lead to weakening. Additional cooling may come in the form of

cold water from falling raindrops (this is because the atmosphere is cooler at higher altitudes). Cloud cover may

also play a role in cooling the ocean, by shielding the ocean surface from direct sunlight before and slightly

after the storm passage. All these effects can combine to produce a dramatic drop in sea surface temperature

over a large area in just a few days.[26]

Scientists estimate that a tropical cyclone releases heat energy at the rate of 50 to 200 exajoules(1018 J) per

day,[19] equivalent to about 1 PW (1015 watt). This rate of energy release is equivalent to 70 times the world

energy consumption of humans and 200 times the worldwide electrical generating capacity, or to exploding a

10-megaton nuclear bomb every 20 minutes.[19][27]

In the lower troposphere, the most obvious motion of clouds is toward the center. However tropical cyclones

also develop an upper-level (high-altitude) outward flow of clouds. These originate from air that has released its

moisture and is expelled at high altitude through the "chimney" of the storm engine. [15] This outflow produces

high, cirrus clouds that spiral away from the center. The clouds thin as they move outwards from the center of

the system and are evaporated. They may be thin enough for the sun to be visible through them. These high

cirrus clouds may be the first signs of an approaching tropical cyclone.[28] As air parcels are lifted within the eye

of the storm the vorticity is reduced, causing the outflow from a tropical cyclone to have anti-cyclonic motion.

[edit]Major basins and related warning centers

Main articles: Tropical cyclone basins and Regional Specialized Meteorological Center

Basins and WMO Monitoring Institutions[29]

Basin Responsible RSMCs and TCWCs

North Atlantic National Hurricane Center (United States)

North-East Pacific National Hurricane Center (United States)

North-Central Pacific Central Pacific Hurricane Center (United States)

North-West Pacific Japan Meteorological Agency

North Indian Ocean India Meteorological Department

South-West Indian Ocean Météo-France

Australian regionBureau of Meteorology† (Australia)Meteorological and Geophysical Agency† (Indonesia)Papua New Guinea National Weather Service†

Southern Pacific Fiji Meteorological ServiceMeteorological Service of New Zealand†

†: Indicates a Tropical Cyclone Warning Center

There are six Regional Specialized Meteorological Centers(RSMCs) worldwide. These organizations are

designated by theWorld Meteorological Organization and are responsible for tracking and issuing bulletins,

warnings, and advisories about tropical cyclones in their designated areas of responsibility. In addition, there

are sixTropical Cyclone Warning Centers(TCWCs) that provide information to smaller regions.[30] The RSMCs

and TCWCs are not the only organizations that provide information about tropical cyclones to the public.

The Joint Typhoon Warning Center (JTWC) issues advisories in all basins except the Northern Atlantic for the

purposes of the United States Government.[31] The Philippine Atmospheric, Geophysical and Astronomical

Services Administration(PAGASA) issues advisories and names for tropical cyclones that approach

the Philippines in the Northwestern Pacific to protect the life and property of its citizens.[32] The Canadian

Hurricane Center(CHC) issues advisories on hurricanes and their remnants for Canadian citizens when they

affect Canada.[33]

On 26 March 2004, Cyclone Catarina became the first recorded South Atlantic cyclone and subsequently

struck southern Brazil with winds equivalent to Category 2 on the Saffir-Simpson Hurricane Scale. As the

cyclone formed outside the authority of another warning center, Brazilian meteorologists initially treated the

system as an extratropical cyclone, although subsequently classified it as tropical.[34]

[edit]Formation

Main article: Tropical cyclogenesis

Map of the cumulative tracks of all tropical cyclones during the 1985–2005 time period. ThePacific Ocean west of

the International Date Linesees more tropical cyclones than any other basin, while there is almost no activity in the Atlantic

Ocean south of the Equator.

Map of all tropical cyclone tracks from 1945 to 2006. Equal-area projection.

Worldwide, tropical cyclone activity peaks in late summer, when 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 while November is the only

month with all the tropical cyclone basins active.[35]

[edit]Times

In the Northern Atlantic Ocean, a distinct cyclone season occurs from June 1 to November 30, sharply peaking

from late August through September.[35] The statistical peak of the Atlantic hurricane season is 10 September.

The Northeast Pacific Ocean has a broader period of activity, but in a similar time frame to the Atlantic.[36] The

Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March and a peak in

early September. In the North Indian basin, storms are most common from April to December, with peaks in

May and November.[35] In the Southern Hemisphere, the tropical cyclone year begins on July 1 and runs all

year-round and encompasses the tropical cyclone seasons, which run from November 1 until the end of April,

with peaks in mid-February to early March.[35][37]

Season lengths and seasonal averages[35][38]

Basin Season start Season end Tropical Storms(>34 knots)

Tropical Cyclones(>63 knots)

Category 3+ TCs(>95 knots)

Northwest Pacific April January 26.7 16.9 8.5

South Indian November April 20.6 10.3 4.3

Northeast Pacific May November 16.3 9.0 4.1

North Atlantic June November 10.6 5.9 2.0

Australia Southwest Pacific November April 9 4.8 1.9

North Indian April December 5.4 2.2 0.4

[edit]Factors

Waves in the trade winds in the Atlantic Ocean—areas of converging winds that move along the same track as the

prevailing wind—create instabilities in the atmosphere that may lead to the formation of hurricanes.

The formation of tropical cyclones is the topic of extensive ongoing research and is still not fully understood.[39] While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting

all of the following conditions. In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed

down to a depth of at least 50 m (160 ft);[40] waters of this temperature cause the overlying atmosphere to be

unstable enough to sustain convection and thunderstorms.[41]Another factor is rapid cooling with height, which

allows the release of the heat of condensation that powers a tropical cyclone.[40] High humidity is needed,

especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions

are more favorable for disturbances to develop.[40] Low amounts of wind shear are needed, as high shear is

disruptive to the storm's circulation.[40] Tropical cyclones generally need to form more than 555 km (345 mi) or

5 degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the

low pressure center and creating a circulation.[40] Lastly, a formative tropical cyclone needs a pre-existing

system of disturbed weather, although without a circulation no cyclonic development will take place. [40] Low-

latitude and low-level westerly wind bursts associated with theMadden-Julian oscillation can create favorable

conditions for tropical cyclogenesis by initiating tropical disturbances.[42]

[edit]Locations

Most tropical cyclones form in a worldwide band of thunderstorm activity called by several names: the

Intertropical Front (ITF), the Intertropical Convergence Zone (ITCZ), or the monsoon trough.[43][44][45]Another

important source of atmospheric instability is found in tropical waves, which cause about 85% of intense

tropical cyclones in the Atlantic ocean, and become most of the tropical cyclones in the Eastern Pacific basin. [46]

[47][48]

Tropical cyclones move westward when equatorward of the subtropical ridge, intensifying as they move. Most

of these systems form between 10 and 30 degrees away of the equator, and 87% form no farther away than

20 degrees of latitude, north or south.[49][50] Because the Coriolis effect initiates and maintains tropical cyclone

rotation, tropical cyclones rarely form or move within about 5 degrees of the equator, where the Coriolis effect

is weakest.[49] However, it is possible for tropical cyclones to form within this boundary as Tropical Storm

Vamei did in 2001 and Cyclone Agni in 2004.[51][52]

[edit]Movement and track

[edit]Steering windsSee also: Prevailing winds

Although tropical cyclones are large systems generating enormous energy, their movements over the Earth's

surface are controlled by large-scale winds—the streams in the Earth's atmosphere. The path of motion is

referred to as a tropical cyclone's track and has been compared by Dr. Neil Frank, former director of

the National Hurricane Center, to "leaves carried along by a stream".[53]

Tropical systems, while generally located equatorward of the 20th parallel, are steered primarily westward by

the east-to-west winds on the equatorward side of the subtropical ridge—a persistent high-pressure area over

the world's oceans.[53] In the tropical North Atlantic and Northeast Pacific oceans, trade winds—another name

for the westward-moving wind currents—steer tropical waveswestward from the African coast and towards the

Caribbean Sea, North America, and ultimately into the central Pacific ocean before the waves dampen out.[47] These waves are the precursors to many tropical cyclones within this region. [46] In the Indian Ocean and

Western Pacific (both north and south of the equator), tropical cyclogenesis is strongly influenced by the

seasonal movement of theIntertropical Convergence Zone and the monsoon trough, rather than by easterly

waves.[54] Tropical cyclones can also be steered by other systems, such as other low pressure systems, high

pressure systems, warm fronts, and cold fronts.

[edit]Coriolis effect

Infrared image of a powerful southern hemisphere cyclone, Monica, near peak intensity, showing clockwise rotation due to

the Coriolis effect

The Earth's rotation imparts an acceleration known as the Coriolis effect, Coriolis acceleration, or

colloquially, Coriolis force. This acceleration causes cyclonic systems to turn towards the poles in the absence

of strong steering currents.[55] The poleward portion of a tropical cyclone contains easterly winds, and the

Coriolis effect pulls them slightly more poleward. The westerly winds on the equatorward portion of the cyclone

pull slightly towards the equator, but, because the Coriolis effect weakens toward the equator, the net drag on

the cyclone is poleward. Thus, tropical cyclones in the Northern Hemisphere usually turn north (before being

blown east), and tropical cyclones in the Southern Hemisphere usually turn south (before being blown east)

when no other effects counteract the Coriolis effect.[21]

The Coriolis effect also initiates cyclonic rotation, but it is not the driving force that brings this rotation to high

speeds – that force is the heat of condensation.[19]

[edit]Interaction with the mid-latitude westerliesSee also: Westerlies

Storm track of Typhoon Ioke, showing recurvature off the Japanese coast in 2006

When a tropical cyclone crosses the subtropical ridgeaxis, its general track around the high-pressure area is

deflected significantly by winds moving towards the general low-pressure area to its north. When the cyclone

track becomes strongly poleward with an easterly component, the cyclone has begunrecurvature.[56] A typhoon

moving through the Pacific Ocean towards Asia, for example, will recurve offshore of Japan to the north, and

then to the northeast, if the typhoon encounters southwesterly winds (blowing northeastward) around a low-

pressure system passing over China or Siberia. Many tropical cyclones are eventually forced toward the

northeast by extratropical cyclones in this manner, which move from west to east to the north of the subtropical

ridge. An example of a tropical cyclone in recurvature was Typhoon Ioke in 2006, which took a similar

trajectory.[57]

[edit]LandfallSee also: List of notable tropical cyclones and Unusual areas of tropical cyclone formation

Officially, landfall is when a storm's center (the center of its circulation, not its edge) crosses the coastline.[58] Storm conditions may be experienced on the coast and inland hours before landfall; in fact, a tropical

cyclone can launch its strongest winds over land, yet not make landfall; if this occurs, then it is said that the

storm made a direct hit on the coast.[58] As a result of the narrowness of this definition, the landfall area

experiences half of a land-bound storm by the time the actual landfall occurs. For emergency preparedness,

actions should be timed from when a certain wind speed or intensity of rainfall will reach land, not from when

landfall will occur.[58]

[edit]Multiple storm interactionMain article: Fujiwhara effect

When two cyclones approach one another, their centers will begin orbiting cyclonically about a point between

the two systems. The two vortices will be attracted to each other, and eventually spiral into the center point and

merge. When the two vortices are of unequal size, the larger vortex will tend to dominate the interaction, and

the smaller vortex will orbit around it. This phenomenon is called the Fujiwhara effect, after Sakuhei Fujiwhara.[59]

[edit]Dissipation

[edit]Factors

Tropical Storm Franklin, an example of a strongly sheared tropical cyclone in the Atlantic Basin during 2005

A tropical cyclone can cease to have tropical characteristics in several different ways. One such way is if it

moves over land, thus depriving it of the warm water it needs to power itself, quickly losing strength. [60] Most

strong storms lose their strength very rapidly after landfall and become disorganized areas of low pressure

within a day or two, or evolve into extratropical cyclones. There is a chance a tropical cyclone could regenerate

if it managed to get back over open warm water, such as with Hurricane Ivan. If it remains over mountains for

even a short time, weakening will accelerate.[61] Many storm fatalities occur in mountainous terrain, as the dying

storm unleashes torrential rainfall,[62] leading to deadlyfloods and mudslides, similar to those that happened

with Hurricane Mitch in 1998.[63] In addition, dissipation can occur if a storm remains in the same area of ocean

for too long, mixing the upper 60 metres (197 ft) of water, dropping sea surface temperatures more than 5

°C (9 °F).[64] Without warm surface water, the storm cannot survive.[65]

A tropical cyclone can dissipate when it moves over waters significantly below 26.5 °C (79.7 °F). This will

cause the storm to lose its tropical characteristics (i.e. thunderstorms near the center and warm core) and

become a remnant low pressure area, which can persist for several days. This is the main dissipation

mechanism in the Northeast Pacific ocean.[66] Weakening or dissipation can occur if it experiences vertical wind

shear, causing the convection and heat engine to move away from the center; this normally ceases

development of a tropical cyclone.[67] In addition, its interaction with the main belt of the Westerlies, by means of

merging with a nearby frontal zone, can cause tropical cyclones to evolve into extratropical cyclones. This

transition can take 1–3 days.[68] Even after a tropical cyclone is said to be extratropical or dissipated, it can still

have tropical storm force (or occasionally hurricane/typhoon force) winds and drop several inches of rainfall. In

the Pacific oceanand Atlantic ocean, such tropical-derived cyclones of higher latitudes can be violent and may

occasionally remain at hurricane or typhoon-force wind speeds when they reach the west coast of North

America. These phenomena can also affect Europe, where they are known as European

windstorms; Hurricane Iris's extratropical remnants are an example of such a windstorm from 1995.[69]In

addition, a cyclone can merge with another area of low pressure, becoming a larger area of low pressure. This

can strengthen the resultant system, although it may no longer be a tropical cyclone. [67] Studies in the 2000s

have given rise to the hypothesis that large amounts of dust reduce the strength of tropical cyclones. [70]

[edit]Artificial dissipation

In the 1960s and 1970s, the United States government attempted to weaken hurricanes throughProject

Stormfury by seeding selected storms with silver iodide. It was thought that the seeding would

cause supercooled water in the outer rainbands to freeze, causing the inner eyewall to collapse and thus

reducing the winds.[71] The winds of Hurricane Debbie—a hurricane seeded in Project Stormfury—dropped as

much as 31%, but Debbie regained its strength after each of two seeding forays. [72] In an earlier episode in

1947, disaster struck when a hurricane east of Jacksonville, Florida promptly changed its course after being

seeded, and smashed into Savannah, Georgia.[73] Because there was so much uncertainty about the behavior

of these storms, the federal government would not approve seeding operations unless the hurricane had a less

than 10% chance of making landfall within 48 hours, greatly reducing the number of possible test storms. The

project was dropped after it was discovered that eyewall replacement cycles occur naturally in strong

hurricanes, casting doubt on the result of the earlier attempts. Today, it is known that silver iodide seeding is

not likely to have an effect because the amount of supercooled water in the rainbands of a tropical cyclone is

too low.[74]

Other approaches have been suggested over time, including cooling the water under a tropical cyclone by

towing icebergs into the tropical oceans.[75] Other ideas range from covering the ocean in a substance that

inhibits evaporation,[76] dropping large quantities of ice into the eye at very early stages of development (so that

the latent heat is absorbed by the ice, instead of being converted to kinetic energy that would feed the positive

feedback loop),[75] or blasting the cyclone apart with nuclear weapons.[18] Project Cirrus even involved throwing

dry ice on a cyclone.[77] These approaches all suffer from one flaw above many others: tropical cyclones are

simply too large and short-lived for any of the weakening techniques to be practical. [78]

[edit]Effects

The aftermath of Hurricane Katrina in Gulfport, Mississippi.

Main article: Effects of tropical cyclones

Tropical cyclones out at sea cause large waves, heavy rain, and high winds, disrupting international shipping

and, at times, causing shipwrecks.[79] Tropical cyclones stir up water, leaving a cool wake behind them, which

causes the region to be less favorable for subsequent tropical cyclones. [26] On land, strongwinds can damage

or destroy vehicles, buildings, bridges, and other outside objects, turning loose debris into deadly flying

projectiles. The storm surge, or the increase in sea level due to the cyclone, is typically the worst effect from

landfalling tropical cyclones, historically resulting in 90% of tropical cyclone deaths. [80] The broad rotation of a

landfalling tropical cyclone, and vertical wind shear at its periphery, spawns tornadoes. Tornadoes can also be

spawned as a result of eyewall mesovortices, which persist until landfall.[81]

Over the past two centuries, tropical cyclones have been responsible for the deaths of about 1.9 million people

worldwide. Large areas of standing water caused by flooding lead to infection, as well as contributing to

mosquito-borne illnesses. Crowded evacuees in shelters increase the risk of disease propagation.[82] Tropical

cyclones significantly interrupt infrastructure, leading to power outages, bridge destruction, and the hampering

of reconstruction efforts.[82][83]

Although cyclones take an enormous toll in lives and personal property, they may be important factors in

the precipitation regimes of places they impact, as they may bring much-needed precipitation to otherwise dry

regions.[84] Tropical cyclones also help maintain the global heat balance by moving warm, moist tropical air to

the middle latitudes and polar regions,[22] and by regulating thethermohaline circulation through upwelling.[85] The storm surge and winds of hurricanes may be destructive to human-made structures, but they also stir up

the waters of coastal estuaries, which are typically important fish breeding locales. Tropical cyclone destruction

spurs redevelopment, greatly increasing local property values.[86]

[edit]Observation and forecasting

[edit]ObservationMain article: Tropical cyclone observation

Sunset view of Hurricane Isidore's rainbands photographed at 7,000 feet (2,100 m)

Intense tropical cyclones pose a particular observation challenge, as they are a dangerous oceanic

phenomenon, and weather stations, being relatively sparse, are rarely available on the site of the storm itself.

In general, surface observations are available only if the storm is passing over an island or a coastal area, or if

there is a nearby ship. Real-time measurements are usually taken in the periphery of the cyclone, where

conditions are less catastrophic and its true strength cannot be evaluated. For this reason, there are teams of

meteorologists that move into the path of tropical cyclones to help evaluate their strength at the point of landfall.[87]

Tropical cyclones far from land are tracked by weather satellites capturing visible and infrared images from

space, usually at half-hour to quarter-hour intervals. As a storm approaches land, it can be observed by land-

based Doppler radar. Radar plays a crucial role around landfall by showing a storm's location and intensity

every several minutes.[88]

In situ measurements, in real-time, can be taken by sending specially equipped reconnaissance flights into the

cyclone. In the Atlantic basin, these flights are regularly flown by United States governmenthurricane hunters.[89] The aircraft used are WC-130 Hercules and WP-3D Orions, both four-engineturboprop cargo aircraft. These

aircraft fly directly into the cyclone and take direct and remote-sensing measurements. The aircraft also

launch GPS dropsondes inside the cyclone. These sondes measure temperature, humidity, pressure, and

especially winds between flight level and the ocean's surface. A new era in hurricane observation began when

a remotely piloted Aerosonde, a small drone aircraft, was flown through Tropical Storm Ophelia as it passed

Virginia's Eastern Shore during the 2005 hurricane season. A similar mission was also completed successfully

in the western Pacific ocean. This demonstrated a new way to probe the storms at low altitudes that human

pilots seldom dare.[90]

A general decrease in error trends in tropical cyclone path prediction is evident since the 1970s

[edit]ForecastingSee also: Tropical cyclone track forecasting,Tropical cyclone prediction model, and Tropical cyclone rainfall

forecasting

Because of the forces that affect tropical cyclone tracks, accurate track predictions depend on determining the

position and strength of high- and low-pressure areas, and predicting how those areas will change during the

life of a tropical system. The deep layer mean flow, or average wind through the depth of the troposphere, is

considered the best tool in determining track direction and speed. If storms are significantly sheared, use of

wind speed measurements at a lower altitude, such as at the 700 hPa pressure surface (3,000 metres / 9,800

feet above sea level) will produce better predictions. Tropical forecasters also consider smoothing out short-

term wobbles of the storm as it allows them to determine a more accurate long-term trajectory. [91] High-speed

computers and sophisticated simulation software allow forecasters to produce computer models that predict

tropical cyclone tracks based on the future position and strength of high- and low-pressure systems. Combining

forecast models with increased understanding of the forces that act on tropical cyclones, as well as with a

wealth of data from Earth-orbiting satellites and other sensors, scientists have increased the accuracy of track

forecasts over recent decades.[92] However, scientists are not as skillful at predicting the intensity of tropical

cyclones.[93]The lack of improvement in intensity forecasting is attributed to the complexity of tropical systems

and an incomplete understanding of factors that affect their development.

[edit]Classifications, terminology, and naming

[edit]Intensity classificationsMain article: Tropical cyclone scales

Three tropical cyclones at different stages of development. The weakest (left) demonstrates only the most basic circular

shape. A stronger storm (top right) demonstrates spiral banding and increased centralization, while the strongest (lower

right) has developed an eye.

Tropical cyclones are classified into three main groups, based on intensity: tropical depressions, tropical

storms, and a third group of more intense storms, whose name depends on the region. For example, if

a tropical storm in the Northwestern Pacific reaches hurricane-strength winds on theBeaufort scale, it is

referred to as a typhoon; if a tropical storm passes the same benchmark in theNortheast Pacific Basin, or in the

Atlantic, it is called a hurricane.[58] Neither "hurricane" nor "typhoon" is used in either the Southern Hemisphere

or the Indian Ocean. In these basins, storms of tropical nature are referred to simply as "cyclones".

As indicated in the table below, each basin uses a separate system of terminology, making comparisons

between different basins difficult. In the Pacific Ocean, hurricanes from the Central North Pacific sometimes

cross the International Date Line into the Northwest Pacific, becoming typhoons (such asHurricane/Typhoon

Ioke in 2006); on rare occasions, the reverse will occur.[94] It should also be noted that typhoons with sustained

winds greater than 67 metres per second (130 kn) or 150 miles per hour (240 km/h) are called Super

Typhoons by the Joint Typhoon Warning Center.[95]

[edit]Tropical depression

A tropical depression is an organized system of clouds and thunderstorms with a defined, closed surface

circulation and maximum sustained winds of less than 17 metres per second (33 kn) or 38 miles per hour

(61 km/h). It has no eye and does not typically have the organization or the spiral shape of more powerful

storms. However, it is already a low-pressure system, hence the name "depression". [15] The practice of

the Philippines is to name tropical depressions from their own naming convention when the depressions are

within the Philippines' area of responsibility.[96]

[edit]Tropical storm

A tropical storm is an organized system of strong thunderstorms with a defined surface circulation and

maximum sustained winds between 17 metres per second (33 kn) (39 miles per hour (63 km/h)) and 32 metres

per second (62 kn) (73 miles per hour (117 km/h)). At this point, the distinctive cyclonic shape starts to develop,

although an eye is not usually present. Government weather services, other than the Philippines, first assign

names to systems that reach this intensity (thus the term named storm).[15]

[edit]Hurricane or typhoon

A hurricane or typhoon (sometimes simply referred to as a tropical cyclone, as opposed to a depression or

storm) is a system with sustained winds of at least 33 metres per second (64 kn) or 74 miles per hour

(119 km/h).[15] A cyclone of this intensity tends to develop an eye, an area of relative calm (and lowest

atmospheric pressure) at the center of circulation. The eye is often visible in satellite images as a small,

circular, cloud-free spot. Surrounding the eye is the eyewall, an area about 16 kilometres (9.9 mi) to 80

kilometres (50 mi) wide in which the strongest thunderstorms and winds circulate around the storm's center.

Maximum sustained winds in the strongest tropical cyclones have been estimated at about 85 metres per

second (165 kn) or 195 miles per hour (314 km/h).[97]

[hide]Tropical Cyclone Classifications (all winds are 10-minute averages)[98][99]

Beaufort scale

10-minute sustained

winds (knots)

N Indian OceanIMD

SW Indian Ocean

MF

AustraliaBOM

SW PacificFMS

NW PacificJMA

NW PacificJTWC

NE Pacific &N Atlantic

NHC, CHC& CPHC

0–6<28 knots (32 mph; 52 km/h)

Depression Trop. Disturbance

Tropical Low

Tropical Depression

Tropical Depression

Tropical Depression

Tropical Depression

7 28–29 knots (32–33 mph; 52–54 km/h)

Deep Depression

Depression

30–33 knots (35–38 mph; 56–61 km/h)

Tropical Storm

8–934–47 knots (39–54 mph; 63–87 km/h)

Cyclonic Storm

Moderate Tropical Storm

Tropical Cyclone (1)

Tropical Cyclone (1)

Tropical Storm

Tropical Storm10

48–55 knots (55–63 mph; 89–102 km/h)

Severe Cyclonic Storm

Severe Tropical Storm

Tropical Cyclone (2)

Tropical Cyclone (2)

Severe Tropical Storm

11

56–63 knots (64–72 mph; 104–117 km/h)

Typhoon

12 64–72 knots (74–83 mph; 119–133 km/h)

Very Severe Cyclonic Storm

Tropical Cyclone

Severe Tropical Cyclone (3)

Severe Tropical Cyclone (3)

Typhoon

Hurricane (1)

73–85 knots (84–98 mph; 135–157 km/h)

Hurricane (2)

86–89 knots (99–102 mph; 159–165 km/h)

Severe Tropical Cyclone (4)

Severe Tropical Cyclone (4)90–106

knots (100–122 mph; 170–196 km/h)

Intense Tropical Cyclone

Major Hurricane (3)

107–114 knots (123–131 mph; 198–211 km/h)

Severe Tropical Cyclone (5)

Severe Tropical Cyclone (5)

115–119 knots (132–137 mph; 213–220 km/h)

Very Intense Tropical Cyclone

Super Typhoon

Major Hurricane (4)

120–135 knots (140–155 mph; 220–250 km/h) Super

Cyclonic Storm

>136 knots (157 mph; 252 km/h)

Major Hurricane (5)

[edit]Origin of storm terms

Taipei 101 endures a typhoon in 2005

The word typhoon, which is used today in the Northwest Pacific, may be derived

from Hindi/Urdu,Persian and Arabic ţūfān (طوفان), which in turn originates from Greek Typhon (Τυφών), a

monster fromGreek mythology associated with storms.[100] The related Portuguese word tufão, used in

Portuguese for typhoons, is also derived from Typhon.[101] The word is also similar to Chinese "taifeng"

("toifung" inCantonese) (颱風 – great winds), and also to the Japanese "taifu" (台風).

The word hurricane, used in the North Atlantic and Northeast Pacific, is derived from huracán, the Spanish

word for the Carib/Taino storm god, Juracán. This god is believed by scholars to have been at least partially

derived from the Mayan creator god, Huracan. Huracan was believed by the Maya to have created dry land out

of the turbulent waters. The god was also credited with later destroying the "wooden people", the precursors to

the "maize people", with an immense storm and flood.[102][103]Huracan is also the source of the word orcan,

another word for a particularly strong European windstorm.[103]

[edit]NamingMain articles: Tropical cyclone naming and Lists of tropical cyclone names

Storms reaching tropical storm strength were initially given names to eliminate confusion when there are

multiple systems in any individual basin at the same time, which assists in warning people of the coming storm.[104] In most cases, a tropical cyclone retains its name throughout its life; however, under special circumstances,

tropical cyclones may be renamed while active. These names are taken from lists that vary from region to

region and are usually drafted a few years ahead of time. The lists are decided on, depending on the regions,

either by committees of the World Meteorological Organization (called primarily to discuss many other issues)

or by national weather offices involved in the forecasting of the storms. Each year, the names of particularly

destructive storms (if there are any) are "retired" and new names are chosen to take their place. Different

countries have different local conventions; for example, in Japan, storms are referred to by number (each year),

such as 台風第 9 号 (Typhoon #9).

[edit]Notable tropical cyclones

Main articles: List of notable tropical cyclones, List of Atlantic hurricanes, and List of Pacific hurricanes

Tropical cyclones that cause extreme destruction are rare, although when they occur, they can cause great

amounts of damage or thousands of fatalities. The 1970 Bhola cyclone is the deadliest tropical cyclone on

record, killing more than 300,000 people[105] and potentially as many as 1 million[106] after striking the densely

populated Ganges Delta region of Bangladesh on 13 November 1970. Its powerful storm surge was

responsible for the high death toll.[105] The North Indian cyclone basin has historically been the deadliest basin.[82][107] Elsewhere, Typhoon Nina killed nearly 100,000 in China in 1975 due to a 100-year flood that caused

62 dams including the Banqiao Dam to fail.[108] The Great Hurricane of 1780 is the deadliest Atlantic

hurricane on record, killing about 22,000 people in theLesser Antilles.[109] A tropical cyclone does need not be

particularly strong to cause memorable damage, primarily if the deaths are from rainfall or mudslides. Tropical

Storm Thelma in November 1991 killed thousands in the Philippines,[110] while in 1982, the unnamed tropical

depression that eventually became Hurricane Paul killed around 1,000 people in Central America.[111]

Hurricane Katrina is estimated as the costliest tropical cyclone worldwide,[112] causing $81.2 billion in property

damage (2008 USD)[113] with overall damage estimates exceeding $100 billion (2005 USD).[112] Katrina killed at

least 1,836 people after striking Louisiana and Mississippi as amajor hurricane in August 2005.[113] Hurricane

Andrew is the second most destructive tropical cyclone in U.S history, with damages totaling $40.7 billion

(2008 USD), and with damage costs at $31.5 billion (2008 USD), Hurricane Ike is the third most destructive

tropical cyclone in U.S history. The Galveston Hurricane of 1900 is the deadliest natural disaster in the United

States, killing an estimated 6,000 to 12,000 people in Galveston, Texas.[114] Hurricane Mitch caused more than

10,000 fatalities in Latin America. Hurricane Iniki in 1992 was the most powerful storm to strike Hawaii in

recorded history, hitting Kauai as a Category 4 hurricane, killing six people, and causing U.S. $3 billion in

damage.[115]Kauai was also struck by Hurricanes Dot (1959) and Iwa (1982) (see List of Hawaii hurricanes).

Other destructive Eastern Pacific hurricanes include Pauline and Kenna, both causing severe damage after

striking Mexico as major hurricanes.[116][117] In March 2004, Cyclone Gafilo struck northeasternMadagascar as a

powerful cyclone, killing 74, affecting more than 200,000, and becoming the worst cyclone to affect the nation

for more than 20 years.[118]

The relative sizes of Typhoon Tip, Cyclone Tracy, and theContiguous United States

The most intense storm on record was Typhoon Tip in the northwestern Pacific Ocean in 1979, which reached

a minimum pressure of 870 mbar (652.5 mmHg) and maximum sustained wind speeds of 165 knots (85 m/s) or

190 miles per hour (310 km/h).[119] Tip, however, does not solely hold the record for fastest sustained winds in a

cyclone. Typhoon Keith in the Pacific and Hurricanes Camille andAllen in the North Atlantic currently share this

record with Tip.[120] Camille was the only storm to actually strike land while at that intensity, making it, with 165

knots (85 m/s) or 190 miles per hour (310 km/h) sustained winds and 183 knots (94 m/s) or 210 miles per hour

(340 km/h) gusts, the strongest tropical cyclone on record at landfall.[121] Typhoon Nancy in 1961 had recorded

wind speeds of 185 knots (95 m/s) or 215 miles per hour (346 km/h), but recent research indicates that wind

speeds from the 1940s to the 1960s were gauged too high, and this is no longer considered the storm with the

highest wind speeds on record.[97] Likewise, a surface-level gust caused by Typhoon Paka on Guam was

recorded at 205 knots (105 m/s) or 235 miles per hour (378 km/h). Had it been confirmed, it would be the

strongest non-tornadic wind ever recorded on the Earth's surface, but the reading had to be discarded since

theanemometer was damaged by the storm.[122] Hurricane Wilma is the most intense tropical cyclone in the

Atlantic Basin and the strongest tropical cyclone in the Western Hemisphere.

In addition to being the most intense tropical cyclone on record, Tip was the largest cyclone on record, with

tropical storm-force winds 2,170 kilometres (1,350 mi) in diameter. The smallest storm on record,Tropical

Storm Marco, formed during October 2008, and made landfall in Veracruz. Marco generated tropical storm-

force winds only 37 kilometres (23 mi) in diameter.[123]

Hurricane John is the longest-lasting tropical cyclone on record, lasting 31 days in 1994. Before the advent of

satellite imagery in 1961, however, many tropical cyclones were underestimated in their durations.[124] John is

also the longest-tracked tropical cyclone in the Northern Hemisphere on record, which had a path of

7,165 miles (13,280 km). Reliable data for Southern Hemisphere cyclones is unavailable.[125]

[edit]Changes caused by El Niño-Southern Oscillation

See also: El Niño-Southern Oscillation

Most tropical cyclones form on the side of the subtropical ridge closer to the equator, then move poleward past

the ridge axis before recurving into the main belt of the Westerlies.[126] When thesubtropical ridge position shifts

due to El Niño, so will the preferred tropical cyclone tracks. Areas west of Japan and Korea tend to experience

much 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.[127] During El Niño years, Guam's chance of a tropical cyclone impact is one-third of the long term average.[128] The tropical Atlantic ocean experiences depressed activity due to increased vertical wind shear across the

region during El Niño years.[129] During La Niña years, the formation of tropical cyclones, along with the

subtropical ridge position, shifts westward across the western Pacific ocean, which increases the landfall threat

toChina.[127]

[edit]Long-term activity trends

See also: Atlantic hurricane reanalysis

Atlantic Multidecadal Cycle since 1950, usingaccumulated cyclone energy (ACE)

Atlantic Multidecadal Oscillation Timeseries, 1856–2009

While the number of storms in the Atlantic has increased since 1995, there is

no obvious global trend; the annual number of tropical cyclones worldwide

remains about 87 ± 10 (Between 77 and 97 tropical cyclones annually).

However, the ability of climatologists to make long-term data analysis in

certain basins is limited by the lack of reliable historical data in some basins,

primarily in the Southern Hemisphere.[130] In spite of that, there is some

evidence that the intensity of hurricanes is increasing. Kerry Emanuel stated,

"Records of hurricane activity worldwide show an upswing of both the

maximum wind speed in and the duration of hurricanes. The energy released

by the average hurricane (again considering all hurricanes worldwide) seems

to have increased by around 70% in the past 30 years or so, corresponding to

about a 15% increase in the maximum wind speed and a 60% increase in

storm lifetime."[131]

Atlantic storms are becoming more destructive financially, since five of the

ten most expensive storms in United States history have occurred since 1990.

According to the World Meteorological Organization, “recent increase in

societal impact from tropical cyclones has been caused largely by rising

concentrations of population and infrastructure in coastal

regions.”[132] Pielke et al. (2008) normalized mainland U.S. hurricane damage

from 1900–2005 to 2005 values and found no remaining trend of increasing

absolute damage. The 1970s and 1980s were notable because of the

extremely low amounts of damage compared to other decades. The decade

1996–2005 was the second most damaging among the past 11 decades, with

only the decade 1926–1935 surpassing its costs. The most damaging single

storm is the 1926 Miami hurricane, with $157 billion of normalized damage.[133]

Often in part because of the threat of hurricanes, many coastal regions had

sparse population between major ports until the advent of automobile tourism;

therefore, the most severe portions of hurricanes striking the coast may have

gone unmeasured in some instances. The combined effects of ship

destruction and remote landfall severely limit the number of intense

hurricanes in the official record before the era of hurricane reconnaissance

aircraft and satellite meteorology. Although the record shows a distinct

increase in the number and strength of intense hurricanes, therefore, experts

regard the early data as suspect.[134]

The number and strength of Atlantic hurricanes may undergo a 50–70 year

cycle, also known as theAtlantic Multidecadal Oscillation. Nyberg et

al. reconstructed Atlantic major hurricane activity back to the early 18th

century and found five periods averaging 3–5 major hurricanes per year and

lasting 40–60 years, and six other averaging 1.5–2.5 major hurricanes per

year and lasting 10–20 years. These periods are associated with the Atlantic

multidecadal oscillation. Throughout, a decadal oscillation related to solar

irradiance was responsible for enhancing/dampening the number of major

hurricanes by 1–2 per year.[135]

Although more common since 1995, few above-normal hurricane seasons

occurred during 1970–94.[136] Destructive hurricanes struck frequently from

1926–60, including many major New England hurricanes. Twenty-one Atlantic

tropical storms formed in 1933, a record only recently exceeded in2005, which

saw 28 storms. Tropical hurricanes occurred infrequently during the seasons

of 1900–25; however, many intense storms formed during 1870–99. During

the 1887 season, 19 tropical storms formed, of which a record 4 occurred

after 1 November and 11 strengthened into hurricanes. Few hurricanes

occurred in the 1840s to 1860s; however, many struck in the early 19th

century, including a1821 storm that made a direct hit on New York City. Some

historical weather experts say these storms may have been as high

as Category 4 in strength.[137]

These active hurricane seasons predated satellite coverage of the Atlantic

basin. Before the satellite era began in 1960, tropical storms or hurricanes

went undetected unless a reconnaissance aircraft encountered one, a ship

reported a voyage through the storm, or a storm hit land in a populated area.[134] The official record, therefore, could miss storms in which no ship

experienced gale-force winds, recognized it as a tropical storm (as opposed to

a high-latitude extra-tropical cyclone, a tropical wave, or a brief squall),

returned to port, and reported the experience.

Proxy records based on paleotempestological research have revealed that

major hurricane activity along the Gulf of Mexico coast varies on timescales of

centuries to millennia.[138][139] Few major hurricanes struck the Gulf coast during

3000–1400 BC and again during the most recent millennium. These quiescent

intervals were separated by a hyperactive period during 1400 BC and 1000

AD, when the Gulf coast was struck frequently by catastrophic hurricanes and

their landfall probabilities increased by 3–5 times. This millennial-scale

variability has been attributed to long-term shifts in the position of the Azores

High,[139] which may also be linked to changes in the strength of the North

Atlantic Oscillation.[140]

According to the Azores High hypothesis, an anti-phase pattern is expected to

exist between the Gulf of Mexico coast and the Atlantic coast. During the

quiescent periods, a more northeasterly position of the Azores High would

result in more hurricanes being steered towards the Atlantic coast. During the

hyperactive period, more hurricanes were steered towards the Gulf coast as

the Azores High was shifted to a more southwesterly position near the

Caribbean. Such a displacement of the Azores High is consistent with

paleoclimatic evidence that shows an abrupt onset of a drier climate

in Haiti around 3200 14 C  years BP,[141] and a change towards more humid

conditions in the Great Plains during the late-Holocene as more moisture was

pumped up the Mississippi Valley through the Gulf coast. Preliminary data

from the northern Atlantic coast seem to support the Azores High hypothesis.

A 3000-year proxy record from a coastal lake in Cape Cod suggests that

hurricane activity increased significantly during the past 500–1000 years, just

as the Gulf coast was amid a quiescent period of the last millennium.

[edit]Global warming

See also: Effects of global warming and Hurricane Katrina and global

warming

The U.S. National Oceanic and Atmospheric Administration Geophysical

Fluid Dynamics Laboratoryperformed a simulation to determine if there is

a statistical trend in the frequency or strength of tropical cyclones over

time. The simulation concluded "the strongest hurricanes in the present

climate may be upstaged by even more intense hurricanes over the next

century as the earth's climate is warmed by increasing levels of

greenhouse gases in the atmosphere".[142]

In an article in Nature, meteorology professor Kerry Emanuel stated that

potential hurricane destructiveness, a measure combining hurricane

strength, duration, and frequency, "is highly correlated with tropical sea

surface temperature, reflecting well-documented climate signals,

includingmultidecadal oscillations in the North Atlantic and North Pacific,

and global warming". Emanuel predicted "a substantial increase in

hurricane-related losses in the twenty-first century".[143] In more recent

work published by Emanuel (in the March 2008 issue of the Bulletin of the

American Meteorological Society), he states that new climate modeling

data indicates “global warming should reduce the global frequency of

hurricanes.”[144] According to the Houston Chronicle, the new work

suggests that, even in a dramatically warming world, hurricane frequency

and intensity may not substantially rise during the next two centuries.[145]

Likewise, P.J. Webster and others published an article

in Science examining the "changes in tropical cyclone number, duration,

and intensity" over the past 35 years, the period when satellite data has

been available. Their main finding was although the number of cyclones

decreased

throughout

the planet

excluding the

north Atlantic

Ocean, there

was a great

increase in

the number

and

proportion of

very strong

cyclones.[146]

The strength of the reported effect is surprising in light of modeling studies[147] that predict only a one-half

category increase in storm intensity as a result of a ~2 °C (3.6 °F) global warming. Such a response would

have predicted only a ~10% increase in Emanuel's potential destructiveness index during the 20th century

rather than the ~75–120% increase he reported.[143] Second, after adjusting for changes in population and

inflation, and despite a more than 100% increase in Emanuel's potential destructiveness index, no statistically

significant increase in the monetary damages resulting from Atlantic hurricanes has been found. [133][148]

Costliest U.S. Atlantic hurricanesTotal estimated property damage, adjusted for wealth normalization[133]

Rank Hurricane Season Cost (2005 USD)

1 "Miami" 1926 $157 billion

2 "Galveston" 1900 $99.4 billion

3 Katrina 2005 $81.0 billion

4 "Galveston" 1915 $68.0 billion

5 Andrew 1992 $55.8 billion

6 "New England" 1938 $39.2 billion

7 "Cuba–Florida" 1944 $38.7 billion

8 "Okeechobee" 1928 $33.6 billion

9 Donna 1960 $26.8 billion

10 Camille 1969 $21.2 billionMain article: List of costliest Atlantic hurricanes

Sufficiently warm sea surface temperatures are considered vital to the development of tropical cyclones.[149] Although neither study can directly link hurricanes with global warming, the increase in sea surface

temperatures is believed to be due to both global warming and natural variability, e.g. the hypothesized Atlantic

Multidecadal Oscillation(AMO), although an exact attribution has not been defined.[150] However, recent

temperatures are the warmest ever observed for many ocean basins.[143]

In February 2007, the United Nations Intergovernmental Panel on

Climate Change released its fourth assessment report on climate change.

The report noted many observed changes in the climate, including

atmospheric composition, global average temperatures, ocean

conditions, among others. The report concluded the observed increase in

tropical cyclone intensity is larger than climate models predict. In addition,

the report considered that it is likely that storm intensity will continue to

increase through the 21st century, and declared it more likely than not

that there has been some human contribution to the increases in tropical

cyclone intensity.[151] However, there is no universal agreement about the

magnitude of the effects anthropogenic global warming has on tropical

cyclone formation, track, and intensity. For example, critics such as Chris

Landsea assert that man-made effects would be "quite tiny compared to

the observed large natural hurricane variability".[152] A statement by

the American Meteorological Society on 1 February 2007 stated that

trends in tropical cyclone records offer "evidence both for and against the

existence of a detectable anthropogenic signal" in tropical cyclogenesis.[153] Although many aspects of a link between tropical cyclones and global

warming are still being "hotly debated",[154] a point of agreement is that no

individual tropical cyclone or season can be attributed to global warming.[150][154] Research reported in the 3 September 2008 issue of Nature found

that the strongest tropical cyclones are getting stronger, in particular over

the North Atlantic and Indian oceans. Wind speeds for the strongest

tropical storms increased from an average of 140 miles per hour

(230 km/h) in 1981 to 156 miles per hour (251 km/h) in 2006, while the

ocean temperature, averaged globally over the all regions where tropical

cyclones form, increased from28.2 °C (82.8 °F) to 28.5

°C (83.3 °F) during this period.[155][156]

[edit]Related cyclone types

Subtropical Storm Gustav in 2002

See also: Cyclone, Extratropical cyclone, andSubtropical cyclone

In addition to tropical cyclones, there are two other classes of cyclones

within the spectrum of cyclone types. These kinds of cyclones, known

asextratropical cyclones and subtropical cyclones, can be stages a

tropical cyclone passes through during itsformation or dissipation.[157] An extratropical cycloneis a storm that derives energy from horizontal

temperature differences, which are typical in higher latitudes. A tropical

cyclone can become extratropical as it moves toward higher latitudes if its

energy source changes from heat released by condensation to

differences in temperature between air masses; although not as

frequently, an extratropical cyclone can transform into a subtropical

storm, and from there into a tropical cyclone.[158] From space, extratropical

storms have a characteristic "comma-shaped" cloud pattern.[159] Extratropical cyclones can also be dangerous when their low-pressure

centers cause powerful winds and high seas.[160]

A subtropical cyclone is a weather system that has some characteristics

of a tropical cyclone and some characteristics of an extratropical cyclone.

They can form in a wide band of latitudes, from theequator to 50°.

Although subtropical storms rarely have hurricane-force winds, they may

become tropical in nature as their cores warm.[161] From an operational

standpoint, a tropical cyclone is usually not considered to become

subtropical during its extratropical transition.[162]

[edit]Tropical cyclones in popular culture

Main article: Tropical cyclones in popular culture

In popular culture, tropical cyclones have made appearances in different

types of media, including films, books, television, music, and electronic

games. The media can have tropical cyclones that are entirely fictional, or

can be based on real events.[163] For example, George Rippey

Stewart's Storm, abest-seller published in 1941, is thought to have

influenced meteorologists into giving female names to Pacific tropical

cyclones.[164] Another example is the hurricane in The Perfect Storm,

which describes the sinking of the Andrea Gail by the 1991 Perfect

Storm.[165] Also, hypothetical hurricanes have been featured in parts of the

plots of series such as The Simpsons, Invasion, Family

Guy, Seinfeld,Dawson's Creek, and CSI: Miami.[163][166][167][168][169][170] The

2004 film The Day After Tomorrowincludes several mentions of actual

tropical cyclones as well as featuring fantastical "hurricane-like" non-

tropical Arctic storms.[171][172]

[edit]See also

Outline of tropical cyclones

Cyclone

Disaster preparedness

HURDAT  (online database)

Hurricane Alley

Saffir–Simpson Hurricane Scale

Tropical cyclones portal

Hypercane

List of wettest tropical cyclones by country

Secondary flow in tropical cyclones

Annual seasons

List of Atlantic hurricane seasons  (current)

List of North Indian Ocean cyclone seasons (current)

List of Pacific hurricane seasons  (current)

List of Pacific typhoon seasons  (current)

List of South-West Indian Ocean cyclone

seasons (current)

List of Australian region cyclone seasons (current)

List of South Pacific cyclone seasons  (current)

Forecasting and preparation

Catastrophe modeling

Hurricane engineering

Hurricane preparedness

Hurricane-proof building

Tropical cyclone watches and warnings

[edit]References

1. ̂  Symonds, Steve (2003-11-17). "Highs and Lows". Wild

Weather (Australian Broadcasting Corporation). Archived from the

original on October 11, 2007. Retrieved 2007-03-23.

2. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What is an extra-

tropical cyclone?". National Oceanic and Atmospheric

Administration. Retrieved 2007-03-23.

3. ^ a b National Weather Service (2005-10-19)."Tropical Cyclone

Structure". JetStream — An Online School for Weather. National

Oceanic & Atmospheric Administration. Retrieved 2009-05-07.

4. ̂  Pasch, Richard J.; Eric S. Blake, Hugh D. Cobb III, and David P.

Roberts (2006-09-28)."Tropical Cyclone Report: Hurricane Wilma:

15–25 October 2005" (PDF). National Hurricane Center. Retrieved

2006-12-14.

5. ̂  Lander, Mark A. (January 1999). "A Tropical Cyclone with a Very

Large Eye" (PDF).Monthly Weather Review 127 (1):

137.Bibcode 1999MWRv..127..137L.doi:10.1175/1520-

0493(1999)127<0137:ATCWAV>2.0.CO;2.ISSN 1520-0493.

Retrieved 2006-12-14.

6. ̂  Pasch, Richard J. and Lixion A. Avila (May 1999). "Atlantic

Hurricane Season of 1996"(PDF). Monthly Weather Review 127 (5):

581–610. Bibcode 1999MWRv..127..581P.doi:10.1175/1520-

0493(1999)127<0581:AHSO>2.0.CO;2.ISSN 1520-0493. Retrieved

2006-12-14.

7. ̂  American Meteorological Society. "AMS Glossary: C". Glossary of

Meteorology. Allen Press. Retrieved 2006-12-14.

8. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What is a

"CDO"?". National Oceanic and Atmospheric Administration.

Retrieved 2007-03-23.

9. ̂  Atlantic Oceanographic and Hurricane Research

Division. "Frequently Asked Questions: What are "concentric

eyewall cycles" (or "eyewall replacement cycles") and why do they

cause a hurricane's maximum winds to weaken?". National Oceanic

and Atmospheric Administration. Retrieved 2006-12-14.

10. ^ a b "Q: What is the average size of a tropical cyclone?". Joint

Typhoon Warning Center. 2009. Retrieved 2009-05-07.

11. ̂  Merrill, Robert T (1983-12-14). "A comparison of Large and Small

Tropical cyclones". American Meteorological Society. Retrieved

2009-05-06.

12. ̂  "Global Guide to Tropical Cyclone Forecasting: chapter 2:

Tropical Cyclone Structure". Bureau of Meteorology. 2009-05-07.

Retrieved 2009-05-06.

13. ̂  K. S. Liu and Johnny C. L. Chan (December 1999). "Size of

Tropical Cyclones as Inferred from ERS-1 and ERS-

2 Data". Monthly Weather Review 127 (12):

2992. Bibcode 1999MWRv..127.2992L . doi:10.1175/1520-

0493(1999)127<2992:SOTCAI>2.0.CO;2.ISSN 1520-0493.

Retrieved 2008-02-24.

14. ̂  "Anthropogenic Effects on Tropical Cyclone Activity.".

Massachusetts Institute of Technology. 2006-02-08. Retrieved

2009-05-07.

15. ^ a b c d e National Weather Service(September 2006). "Hurricanes...

Unleashing Nature's Fury: A Preparedness Guide"(PDF). National

Oceanic and Atmospheric Administration. Archived from the

originalon February 26, 2008. Retrieved 2006-12-02.

16. ̂  Gary M. Barnes and Mark D. Powell (August 1995). "Evolution of

the Inflow Boundary Layer of Hurricane Gilbert (1988)". Monthly

Weather Review (American Meteorological Society) 123 (8):

2348. Bibcode 1995MWRv..123.2348B . doi:10.1175/1520-

0493(1995)123<2348:EOTIBL>2.0.CO;2.ISSN 1520-0493.

17. ̂  Dr. Frank Marks (2003-01-27). "Fifth International Workshop on

Tropical Cyclones Topic 1 Tropical Cyclone Structure and Structure

Change". Atlantic Oceanographic and Meteorological Laboratory.

Retrieved 2009-11-23.

18. ^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: Why

don't we try to destroy tropical cyclones by nuking them?". National

Oceanic and Atmospheric Administration. Retrieved 2006-07-25.

19. ^ a b c d "NOAA FAQ: How much energy does a hurricane

release?". National Oceanic & Atmospheric Administration. August

2001. Retrieved 2009-06-30.

20. ̂  "Coriolis force (physics).". Encyclopaedia Britannica. 2008-02-25.

Retrieved 2009-05-07.

21. ^ a b "Tropical cyclone: Tropical cyclone tracks.". Encyclopædia

Britannica. 2008-02-25. Retrieved 2009-05-07.

22. ^ a b National Weather Service (2005-10-19)."Tropical Cyclone

Introduction".JetStream — An Online School for Weather.National

Oceanic & Atmospheric Administration. Retrieved 2010-09-07.

23. ̂  "Are the winds on one side of a hurricane faster than on the other

side?". Ask the Experts: Hurricanes. USA Today. November 11,

2007. Retrieved September 9, 2011.

24. ^ a b "How are tropical cyclones different to mid-latitude

cyclones?". Frequently Asked Questions. Bureau of Meteorology.

Archived from the original on 2008-05-04. Retrieved 2006-03-31.

25. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Doesn't the friction

over land kill tropical cyclones?".National Oceanic & Atmospheric

Administration. Retrieved 2006-07-25.

26. ^ a b Eric A. D'Asaro and Peter G. Black. (2006). "J8.4 Turbulence in

the Ocean Boundary Layer Below Hurricane

Dennis"(PDF). University of Washington. Retrieved 2008-02-22.

27. ̂  "Hurricanes: Keeping an eye on weather's biggest

bullies.". University Corporation for Atmospheric Research. 2006-

03-31. Retrieved 2009-05-07.

28. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What's it like to go

through a hurricane on the ground? What are the early warning

signs of an approaching tropical cyclone?". National Oceanic and

Atmospheric Administration. Retrieved 2006-07-26.

29. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What regions

around the globe have tropical cyclones and who is responsible for

forecasting there?".National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

30. ̂  "Regional Specialized Meteorological Center". Tropical Cyclone

Program (TCP).World Meteorological Organization. 2006-04-25.

Retrieved 2006-11-05.

31. ̂  "Joint Typhoon Warning Center Mission Statement.". Joint

Typhoon Warning Center. 2007-11-09. Archived from the

original on April 9, 2008. Retrieved 2009-05-07.

32. ̂  "Mission Vision". Philippine Atmospheric, Geophysical and

Astronomical Services Administration. 2008-02-24. Retrieved 2009-

05-07.

33. ̂  "Canadian Hurricane Center". Canadian Hurricane Center. 2008-

02-24. Retrieved 2009-05-07.

34. ̂  Marcelino, Emerson Vieira; Isabela Pena Viana de Oliveira

Marcelino; Frederico de Moraes Rudorff (2004). "Cyclone Catarina:

Damage and Vulnerability Assessment"(PDF). Santa Catarina

Federal University. Retrieved 2006-12-24.

35. ^ a b c d e Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: When

is hurricane season?".National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

36. ̂  McAdie, Colin (2007-05-10). "Tropical Cyclone

Climatology". National Hurricane Center. Retrieved 2007-06-09.

37. ̂  "Tropical Cyclone Operational Plan for the Southeastern Indian

Ocean and the South Pacific Oceans". World Meteorological

Organization. 2009-03-10. Retrieved 2009-05-06.

38. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What are the

average, most, and least tropical cyclones occurring in each

basin?". National Oceanic and Atmospheric Administration.

Retrieved 2006-11-30.

39. ̂  Ross., Simon (1998). Natural Hazards.(Illustrated ed.). Nelson

Thornes. p. 96.ISBN 0748739513, 9780748739516. Retrieved

2009-05-07.

40. ^ a b c d e f Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: How do

tropical cyclones form?". National Oceanic and Atmospheric

Administration. Retrieved 2006-07-26.

41. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Why do tropical

cyclones require 80 °F (27   °C)  ocean temperatures to

form?". National Oceanic and Atmospheric Administration.

Retrieved 2006-07-25.

42. ̂  Kazuyoshi Kikuchi, Bin Wang, and Hironori Fudeyasu

(2009). "Genesis of tropical cyclone Nargis revealed by multiple

satellite observations". Geophysical Research Letters 36 (6):

L06811. Bibcod

e 2009GeoRL..3606811K .doi:10.1029/2009GL037296.

43. ̂  Fritz Korek (2000-11-21). "Marine Meteorological Glossary".

Marine Knowledge Centre. Retrieved 2009-05-06.

44. ̂  "Formation of Tropical Cyclones".Philippine Atmospheric,

Geophysical and Astronomical Services Administration. 2008.

Retrieved 2009-05-06.

45. ̂  DeCaria, Alex (2005). "Lesson 5   – Tropical Cyclones:

Climatology.". ESCI 344 – Tropical Meteorology. Millersville

University. Archived from the original on 2008-05-07. Retrieved

2008-02-22.

46. ^ a b Avila, Lixion, Lixion A.; Richard Pasch (March 1995). "Atlantic

tropical systems of 1993" (PDF). Monthly Weather Review 123(3):

887–896. Bibcode 1995MWRv..123..887A . doi:10.1175/1520-

0493(1995)123<0887:ATSO>2.0.CO;2.ISSN 1520-0493. Retrieved

2006-07-25.

47. ^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: What is

an easterly wave?".National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

48. ̂  Landsea, Chris (June 1993). "A Climatology of Intense (or Major)

Atlantic Hurricanes"(PDF). Monthly Weather Review 121 (6): 1703–

1713. Bibcode 1993MWRv..121.1703L . doi:10.1175/1520-

0493(1993)121<1703:ACOIMA>2.0.CO;2.ISSN 1520-0493.

Retrieved 2006-03-25.

49. ^ a b Neumann, Charles J. "Worldwide Tropical Cyclone Tracks

1979-88". Global Guide to Tropical Cyclone Forecasting.Bureau of

Meteorology. Retrieved 2006-12-12.

50. ̂  "Tropical Cyclones and Global Climate Change: A Post-IPCC

Assessment.".National Oceanic and Atmospheric Administration.

2002-10-08. Retrieved 2009-05-07.

51. ̂  "Monthly Global Tropical Cyclone Summary, December

2001". Gary Padgett. Australian Severe Weather Index. Retrieved

2009-05-06.

52. ̂  "Annual Tropical Cyclone Report 2004".Joint Typhoon Warning

Center. 2006. Retrieved 2009-05-06.

53. ^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: What

determines the movement of tropical cyclones?". National Oceanic

and Atmospheric Administration. Retrieved 2006-07-25.

54. ̂  DeCaria, Alex (2005). "Lesson 5   – Tropical Cyclones:

Climatology.". ESCI 344 – Tropical Meteorology. Millersville

University. Archived from the original on May 7, 2008. Retrieved

2008-02-22.

55. ̂  Baum, Steven K (1997-01-20). "The Glossary: Cn-Cz.". Glossary

of Oceanography and the Related Geosciences with

References. Texas A&M University. Retrieved 2006-11-29.

56. ̂  "Section 2: Tropical Cyclone Motion Terminology". United States

Naval Research Laboratory. 2007-04-10. Retrieved 2009-05-07.

57. ̂  Powell, Jeff, et al. (May 2007). "Hurricane Ioke: 20–27 August

2006". 2006 Tropical Cyclones Central North Pacific. Central Pacific

Hurricane Center. Retrieved 2007-06-09.

58. ^ a b c d National Hurricane Center (2005)."Glossary of NHC/TPC

Terms". National Oceanic and Atmospheric Administration.

Retrieved 2006-11-29.

59. ̂  "Fujiwhara effect describes a stormy waltz". USA Today. 2007-11-

09. Retrieved 2008-02-21.

60. ̂  "Subject   : C2) Doesn't the friction over land kill tropical

cyclones?". National Hurricane Center. National Oceanic and

Atmospheric Administration. 2008-02-25. Retrieved 2009-05-07.

61. ̂  "Tropical Cyclones Affecting Inland Pilbara towns.". Bureau of

Meteorology. Retrieved 2009-05-07.

62. ̂  Yuh-Lang Lin, S. Chiao, J. A. Thurman, D. B. Ensley, and J. J.

Charney. Some Common Ingredients for heavy Orographic Rainfall

and their Potential Application for Prediction.Retrieved on 2007-04-

26.

63. ̂  National Hurricane Center (1998). NHC Mitch Report "Hurricane

Mitch Tropical Cyclone Report". Retrieved 2006-04-20.

64. ̂  Joint Typhoon Warning Center. 1.13 Local Effects on the

Observed Large-scale Circulations. Retrieved on 2008-02-25.

65. ̂  Shay, Lynn K., Russell L. Elsberry and Peter G. Black (May

1989). "Vertical Structure of the Ocean Current Response to a

Hurricane"(PDF). Journal of Physical Oceanography 19(5):

649. Bibcode 1989JPO....19..649S.doi:10.1175/1520-

0485(1989)019<0649:VSOTOC>2.0.CO;2.ISSN 1520-0485.

Retrieved 2006-12-12.

66. ̂  Edwards, Jonathan. "Tropical Cyclone Formation".

HurricaneZone.net. Archived from the original on February 21,

2007. Retrieved 2006-11-30.

67. ^ a b Chih-Pei Chang (2004). East Asian Monsoon. World

Scientific.ISBN 9812387692. OCLC 61353183.

68. ̂  United States Naval Research Laboratory(1999-09-23). "Tropical

Cyclone Intensity Terminology". Tropical Cyclone Forecasters'

Reference Guide. Retrieved 2006-11-30.

69. ̂  Rappaport, Edward N. (2000-11-02)."Preliminary Report:

Hurricane Iris: 22–4 August September 1995". National Hurricane

Center. Retrieved 2006-11-29.

70. ̂  "African Dust Linked To Hurricane Strength". All Things

Considered. National Public Radio. 2008-09-05. Retrieved 2009-05-

07.

71. ̂  "Project Stormfury". Hurricane Research Division. National

Oceanic and Atmospheric Administration. 2009-02-07. Retrieved

2009-05-07.

72. ̂  "Project Stormfury: A Scientific Chronicle 1962-1983.". National

Oceanic and Atmospheric Administration. American Meteorological

Society. 2000-05-23. Retrieved 2009-05-07.

73. ̂  Whipple, Addison (1982). Storm. Alexandria, VA: Time Life

Books. p. 151. ISBN 0-8094-4312-0.

74. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Why don't we try

to destroy tropical cyclones by seeding them with silver

iodide?". National Oceanic and Atmospheric Administration.

Retrieved 2006-07-25.

75. ^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: Why

don't we try to destroy tropical cyclones by cooling the surface

waters with icebergs or deep ocean water?". National Oceanic and

Atmospheric Administration. Retrieved 2006-07-25.

76. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Why don't we try

to destroy tropical cyclones by placing a substance on the ocean

surface?". National Oceanic and Atmospheric Administration.

Retrieved 2006-07-25.

77. ̂  Scotti, R. A. (2003). Sudden Sea: The Great Hurricane of

1938 (1st ed.). Little, Brown, and Company. p. 47. ISBN 0-316-

73911-1.OCLC 51861977.

78. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Why do not we try

to destroy tropical cyclones by (fill in the blank)?". National Oceanic

and Atmospheric Administration. Retrieved 2006-07-25.

79. ̂  David Roth and Hugh Cobb (2001)."Eighteenth Century Virginia

Hurricanes". NOAA. Retrieved 2007-02-24.

80. ̂  James M. Shultz, Jill Russell and Zelde Espinel

(2005). "Epidemiology of Tropical Cyclones: The Dynamics of

Disaster, Disease, and Development". Oxford Journal. Retrieved

2007-02-24.

81. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: Are TC tornadoes

weaker than midlatitude tornadoes?". National Oceanic and

Atmospheric Administration. Retrieved 2006-07-25.

82. ^ a b c Shultz, James M., Jill Russell and Zelde Espinel (July

2005). "Epidemiology of Tropical Cyclones: The Dynamics of

Disaster, Disease, and Development". Epidemiologic

Reviews 27 (1): 21–25.doi:10.1093/epirev/mxi011.PMID 15958424.

Retrieved 2006-12-14.

83. ̂  Staff Writer (2005-08-30). "Hurricane Katrina Situation Report

#11" (PDF). Office of Electricity Delivery and Energy Reliability

(OE)United States Department of Energy. Retrieved 2007-02-24.

84. ̂  National Oceanic and Atmospheric Administration. 2005 Tropical

Eastern North Pacific Hurricane Outlook. Retrieved on 2006-05-02.

85. ̂  Emanuel, Kerry (July 2001). "Contribution of tropical cyclones to

meridional heat transport by the oceans". Journal of Geophysical

Research 106 (D14): 14771–

14781. Bibcode 2001JGR...10614771E .doi:10.1029/2000JD900641.

86. ̂  Christopherson, Robert W. (1992).Geosystems: An Introduction to

Physical Geography. New York: Macmillan Publishing Company.

pp. 222–224. ISBN 0-02-322443-6.

87. ̂  Florida Coastal Monitoring Program. "Project

Overview". University of Florida. Archived from the original on May

3, 2006. Retrieved 2006-03-30.

88. ̂  "Observations". Central Pacific Hurricane Center. 2006-12-09.

Retrieved 2009-05-07.

89. ̂  403rd Wing. "The Hurricane Hunters".53rd Weather

Reconnaissance Squadron. Retrieved 2006-03-30.

90. ̂  Lee, Christopher. "Drone, Sensors May Open Path Into Eye of

Storm". The Washington Post. Retrieved 2008-02-22.

91. ̂  "Influences on Tropical Cyclone Motion".United States Navy.

Retrieved 2007-04-10.

92. ̂  National Hurricane Center (22 May 2006)."Annual average model

track errors for Atlantic basin tropical cyclones for the period 1994-

2005, for a homogeneous selection of "early" models". National

Hurricane Center Forecast Verification. National Oceanic and

Atmospheric Administration. Retrieved 2006-11-30.

93. ̂  National Hurricane Center (2006-05-22)."Annual average official

track errors for Atlantic basin tropical cyclones for the period 1989-

2005, with least-squares trend lines superimposed". National

Hurricane Center Forecast Verification. National Oceanic and

Atmospheric Administration. Retrieved 2006-11-30.

94. ̂  Central Pacific Hurricane Center (2004)."Hurricane John

Preliminary Report".National Oceanic and Atmospheric

Administration. Retrieved 2007-03-23.

95. ̂  Bouchard, R. H. (April 1990). "A Climatology of Very Intense

Typhoons: Or Where Have All the Super Typhoons Gone?" (PPT).

Archived from the original on March 16, 2007. Retrieved 2006-12-

05.

96. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What are the

upcoming tropical cyclone names?".National Oceanic and

Atmospheric Administration. Retrieved 2006-12-11.

97. ^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: Which

is the most intense tropical cyclone on record?". NOAA. Retrieved

2006-07-25.

98. ̂  National Hurricane Center. Subject: A1) What is a hurricane,

typhoon, or tropical cyclone? Retrieved on 2008-02-25.

99. ̂  Bureau of Meteorology. Global Guide to Tropical Cyclone

Forecasting Retrieved on 2008-02-25.

100. ̂  "Typhoon". The American Heritage Dictionary of the English

Language (4th ed.).Dictionary.com. 2004. Retrieved 2006-12-14.

101. ̂  "Disaster Controlled Vocabulary (VDC)"(PDF). Centro Regional

de Información sobre Desastres. Archived from the original on

2008-02-26. Retrieved 2008-01-24.

102. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What is the origin

of the word "hurricane"?". National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

103.^ a b READ, KAY ALMERE; and JASON GONZÁLEZ(2000). Handbook of

Mesoamerican Mythology. Oxford: ABC-CLIO. p. 200. ISBN 1-

85109-340-0. OCLC 43879188.

104. ̂  "Worldwide Tropical Cyclone Names.".National Hurricane

Center. National Oceanic and Atmospheric Administration. 2009.

Retrieved 2009-05-07.

105.^ a b Chris Landsea (1993). "Which tropical cyclones have caused

the most deaths and most damage?". Hurricane Research Division.

Retrieved 2007-02-23.

106. ̂  Lawson (1999-11-02). "South Asia: A history of

destruction". British Broadcasting Corporation. Retrieved 2007-02-

23.

107. ̂  Frank, Neil L. and S. A. Husain (June 1971)."The Deadliest

Tropical Cyclone in History"(PDF). Bulletin of the American

Meteorological Society 52 (6): 438–

445. Bibcode 1971BAMS...52..438F . doi:10.1175/1520-

0477(1971)052<0438:TDTCIH>2.0.CO;2.ISSN 1520-0477.

Retrieved 2006-12-14.

108. ̂  Linda J. Anderson-Berry. Fifth International Workshop on

Tropycal Cyclones: Topic 5.1: Societal Impacts of Tropical

Cyclones.Retrieved on 2008-02-26.

109. ̂  National Hurricane Center (1997-04-22)."The Deadliest Atlantic

Tropical Cyclones, 1492-1996". National Oceanic and Atmospheric

Administration. Retrieved 2006-03-31.

110. ̂  Joint Typhoon Warning Center. "Typhoon Thelma

(27W)" (PDF). 1991 Annual Tropical Cyclone Report. Retrieved

2006-03-31.

111. ̂  Gunther, E. B., R.L. Cross, and R.A. Wagoner (May

1983). "Eastern North Pacific Tropical Cyclones of

1982" (PDF). Monthly Weather Review 111 (5):

1080. Bibcode 1983MWRv..111.1080G . doi:10.1175/1520-

0493(1983)111<1080:ENPTCO>2.0.CO;2.ISSN 1520-0493.

Retrieved 2006-03-31.

112.^ a b Earth Policy Institute (2006). "Hurricane Damages Sour to New

Levels". United States Department of Commerce. Retrieved 2007-

02-23.

113.^ a b Knabb, Richard D., Jamie R. Rhome and Daniel P. Brown (20

December 2005)."Tropical Cyclone Report: Hurricane Katrina: 23–

30 August 2005" (PDF). National Hurricane Center. Retrieved 2006-

05-30.

114. ̂  National Hurricane Center. Galveston Hurricane 1900. Retrieved

on 2008-02-24.

115. ̂  Central Pacific Hurricane Center. "Hurricane Iniki Natural Disaster

Survey Report".National Oceanic and Atmospheric Administration.

Retrieved 2006-03-31.

116. ̂  Lawrence, Miles B. (7 November 1997)."Preliminary Report:

Hurricane Pauline: 5–10 October 1997". National Hurricane Center.

Retrieved 2006-03-31.

117. ̂  Franklin, James L. (26 December 2002)."Tropical Cyclone Report:

Hurricane Kenna: 22–26 October 2002". National Hurricane Center.

Retrieved 2006-03-31.

118. ̂  World Food Programme (2004). "WFP Assists Cyclone And Flood

Victims in Madagascar". Retrieved 2007-02-24.

119. ̂  George M. Dunnavan & John W. Dierks (1980). "An Analysis of

Super Typhoon Tip (October 1979)" (PDF). Joint Typhoon Warning

Center. Retrieved 2007-01-24.

120. ̂  Ferrell, Jesse (26 October 1998). "Hurricane Mitch".

Weathermatrix.net. Archived from the original on September 28,

2007. Retrieved 2006-03-30.

121. ̂  NHC Hurricane Research Division (2006-02-17). "Atlantic

hurricane best track ("HURDAT")". NOAA. Retrieved 2007-02-22.

122. ̂  Houston, Sam, Greg Forbes and Arthur Chiu (17 August

1998). "Super Typhoon Paka's (1997) Surface Winds Over

Guam". National Weather Service. Retrieved 2006-03-30.

123. ̂  Neal Dorst (May 29, 2009). "Subject: E5) Which are the largest

and smallest tropical cyclones on record?". National Hurricane

Center. Retrieved May 29, 2009.

124. ̂  Neal Dorst (2006). "Which tropical cyclone lasted the longest?".

Hurricane Research Division. Retrieved 2007-02-23.

125. ̂  Neal Dorst (2006). "What is the farthest a tropical cyclone has

traveled   ?" . Hurricane Research Division. Retrieved 2007-02-23.

126. ̂  Joint Typhoon Warning Center (2006). "3.3 JTWC Forecasting

Philosophies". United States Navy. Retrieved 2007-02-11.

127.^ a b M. C. Wu, W. L. Chang, and W. M. Leung (2003). "Impacts of

El Niño-Southern Oscillation Events on Tropical Cyclone Landfalling

Activity in the Western North Pacific". Journal of Climate 17 (6):

1419–1428. Bibcode 2004JCli...17.1419W.doi:10.1175/1520-

0442(2004)017<1419:IOENOE>2.0.CO;2.ISSN 1520-0442.

Retrieved 2007-02-11.

128. ̂  Pacific ENSO Applications Climate Center."Pacific ENSO Update:

4th Quarter, 2006. Vol. 12 No. 4". Retrieved 2008-03-19.

129. ̂  Edward N. Rappaport (September 1999)."Atlantic Hurricane

Season of 1997".Monthly Weather Review 127 (9):

2012.Bibcode 1999MWRv..127.2012R.doi:10.1175/1520-

0493(1999)127<2012:AHSO>2.0.CO;2.ISSN 1520-0493. Retrieved

2009-07-18.

130. ̂  Chris Landsea, Chris et al. (2006-07-28)."Can We Detect Trends

in Extreme Tropical Cyclones?" (PDF). Science 313 (5786): 452–

454. doi:10.1126/science.1128448.PMID 16873634. Retrieved

2007-06-09.

131. ̂  Emanuel, Kerry (January 2006)."Anthropogenic Effects on

Tropical Cyclone Activity". Retrieved 2006-03-30.

132. ̂  "Summary Statement on Tropical Cyclones and Climate

Change" (PDF) (Press release). World Meteorological Organization.

2006-12-04. Retrieved 2009-05-07.

133.^ a b c Pielke, Roger A., Jr. et al. (2008)."Normalized Hurricane

Damage in the United States: 1900–2005" (PDF). Natural Hazards

Review 9 (1): 29–42.doi:10.1061/(ASCE)1527-6988(2008)9:1(29).

Retrieved 2009-05-07.

134.^ a b Neumann, Charles J. "1.3: A Global Climatology". Global Guide

to Tropical Cyclone Forecasting. Bureau of Meteorology. Retrieved

2006-11-30.

135. ̂  Nyberg, J.; Winter, A.; Malmgren, B. A. (2005). "Reconstruction of

Major Hurricane Activity". Eos Trans. AGU 86 (52, Fall Meet.

Suppl.): Abstract PP21C–1597. Retrieved 2009-05-07.

136. ̂  Risk Management Solutions (March 2006)."U.S. and Caribbean

Hurricane Activity Rates." (PDF). Retrieved 2006-11-30.

137. ̂  Center for Climate Systems Research."Hurricanes, Sea Level

Rise, and New York City". Columbia University. Archived from the

original on January 2, 2007. Retrieved 2006-11-29.

138. ̂  Liu, Kam-biu (1999). "Millennial-scale variability in catastrophic

hurricane landfalls along the Gulf of Mexico coast". 23rd

Conference on Hurricanes and Tropical Meteorology. Dallas,

Texas, United States of America: American Meteorological Society.

pp. 374–377.

139.^ a b Liu, Kam-biu; Fearn, Miriam L. (2000). "Reconstruction of

Prehistoric Landfall Frequencies of Catastrophic Hurricanes in

Northwestern Florida from Lake Sediment Records". Quaternary

Research 54 (2): 238–

245. Bibcode 2000QuRes..54..238L.doi:10.1006/qres.2000.2166.

140. ̂  Elsner, James B.; Liu, Kam-biu; Kocher, Bethany (2000). "Spatial

Variations in Major U.S. Hurricane Activity: Statistics and a Physical

Mechanism". Journal of Climate 13(13): 2293–

2305. Bibcode 2000JCli...13.2293E . doi:10.1175/1520-

0442(2000)013<2293:SVIMUS>2.0.CO;2.ISSN 1520-0442.

141. ̂  Higuera-Gundy, Antonia et al. (1999). "A 10,300 14C yr Record of

Climate and Vegetation Change from Haiti". Quaternary

Research 52 (2): 159–

170. Bibcode 1999QuRes..52..159H .doi:10.1006/qres.1999.2062.

142. ̂  Geophysical Fluid Dynamics Laboratory."Global Warming and

Hurricanes". National Oceanic and Atmospheric Administration.

Retrieved 2006-11-29.

143.^ a b c Emanuel, Kerry (2005). "Increasing destructiveness of tropical

cyclones over the past 30 years" (PDF). Nature 436 (7051): 686–

688. Bibcode 2005Natur.436..686E.doi:10.1038/nature03906.PMID 

16056221. Retrieved 2006-03-20.

144. ̂  Emanuel, Kerry; Sundararajan, Ragoth, Williams, John (March

2008). "Hurricanes and Global Warming: Results from Downscaling

IPCC AR4 Simulations". Bulletin of the American Meteorological

Society 89 (3): 347–

367. Bibcode 2008BAMS...89..347E.doi:10.1175/BAMS-89-3-347.

145. ̂  Berger, Eric (2008-04-12). "Hurricane expert reconsiders global

warming's impact".Houston Chronicle. Retrieved 2010-07-31.

146. ̂  Webster, P. J., G. J. Holland, J. A. Curry and H.-R. Chang (16

September 2005). "Changes in Tropical Cyclone Number, Duration,

and Intensity in a Warming

Environment" (PDF).Science 309 (5742): 1844–

1846. Bibcode 2005Sci...309.1844W .doi:10.1126/science.1116448.

PMID 16166514. Retrieved 2006-03-20.

147. ̂  Knutson, Thomas R. and Robert E. Tuleya (2004). "Impact of

CO2-Induced Warming on Simulated Hurricane Intensity and

Precipitation: Sensitivity to the Choice of Climate Model and

Convective Parameterization". Journal of Climate 17 (18): 3477–

3494. Bibcode 2004JCli...17.3477K.doi:10.1175/1520-

0442(2004)017<3477:IOCWOS>2.0.CO;2.ISSN 1520-0442.

148. ̂  Pielke, R. A. Jr (2005). "Meteorology: Are there trends in

hurricane destruction?". Nature438 (7071):

E11. Bibcode 2005Natur.438E..11P .doi:10.1038/nature04426.PMID 

16371954.

149. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: How do tropical

cyclones form?". NOAA. Retrieved 2006-07-26.

150.^ a b Stefan Rahmstorf, Michael E. Mann, Rasmus Benestad, Gavin

Schmidt andWilliam Connolley (2 September 2005)."Hurricanes and

Global Warming   — Is There a Connection?" . RealClimate.

Retrieved 2006-03-20.

151. ̂  Richard Alley, et al. (2007). "Contribution of Working Group I to

the Fourth Assessment Report of the Intergovernmental Panel on

Climate Change". United Nations. Retrieved 2007-02-23.

152. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What may happen

with tropical cyclone activity due to global warming?". NOAA.

Retrieved 2007-06-02.

153. ̂  American Meteorological Society; Droegemeier, Kelvin K.; Levit,

Jason J.; Sinclair, Carl; Jahn, David E.; Hill, Scott D.; Mueller, Lora;

Qualley, Grant et al. (2007-02-01). "Climate Change: An Information

Statement of the American Meteorological Society" (PDF). Bulletin

of the American Meteorological Society 88 (7):

5. Bibcode 2007BAMS...88....5K . doi:10.1175/BAMS-88-7-Kelleher.

Retrieved 2007-06-03.

154.^ a b World Meteorological Organization (11 December

2006). "Statement on Tropical Cyclones and Climate

Change" (PDF). p. 6. Retrieved 2007-06-02.

155. ̂  Hurricanes are getting fiercer Nature, Retrieved on 4 September

2008.

156. ̂  Warmer Seas Linked to Strengthening Hurricanes: Study Fuels

Global Warming Debate Newswise, Retrieved on 4 September

2008.

157. ̂  "Fifth International Workshop on Tropical Cyclones". World

Meteorological Organization. 2003-08-03. Retrieved 2009-05-06.

158. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What is an extra-

tropical cyclone?". National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

159. ̂  "Lesson 14: Background: Synoptic Scale".University of

Wisconsin–Madison. 2008-02-25. Retrieved 2009-05-06.

160. ̂  "An Overview of Coastal Land Loss: With Emphasis on the

Southeastern United States.". United States Geological Survey.

2008. Retrieved 2009-05-06.

161. ̂  Atlantic Oceanographic and Meteorological Laboratory, Hurricane

Research Division."Frequently Asked Questions: What is a sub-

tropical cyclone?". National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

162. ̂  Padgett, Gary (2001). "Monthly Global Tropical Cyclone Summary

for December 2000". Retrieved 2006-03-31.

163.^ a b Atlantic Oceanographic and Meteorological Laboratory,

Hurricane Research Division. "Frequently Asked Questions: What

fictional books, plays, and movies have been written involving

tropical cyclones?". National Oceanic and Atmospheric

Administration. Retrieved 2006-07-25.

164. ̂  Heidorn, Keith C. "George Stewart's Storm: Remembering A

Classic.". The Weather Doctor. Retrieved 2006-12-10.

165. ̂  McCown, Sean (2004-12-13). "Unnamed Hurricane

1991". Satellite Events Art Gallery: Hurricanes. National Climatic

Data Center. Retrieved 2007-02-04.

166. ̂  "Hurricane Neddy   – Episode Overview" . Yahoo! TV. Retrieved

2008-02-26.

167. ̂  "Family Guy: One if by Clam, Two if by Sea   – Summary" .

starpulse.com. Retrieved 2008-02-26.

168. ̂  "Dawson's Creek   – Hurricane" . "Yahoo! TV. Retrieved 2008-02-

25.

169. ̂  TheNewsGuy(Mike). "The Checks (Seinfeld Episode Script)".

Seinfeldscripts.com. Retrieved 2007-02-25.

170. ̂  "CSI: Miami Episodes   – Episode Detail: Hurricane Anthony" . TV

Guide. Retrieved 2008-02-25.

171. ̂  "The Day After Tomorrow Movie Synopsis". Tribute.ca. Retrieved

2008-02-26.

172. ̂  "The Day After Tomorrow (2004)". The New York Times.

Retrieved 2008-02-26.

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