what is reason for cyclone?

Question

i want to know

Answer 1

the reason for cyclone is low pressure region.as we know that wind flows from low to high pressure region and due to the coriolis forces which is the main cause of shifting the air to left or right in northern & southern hemisphere resply.
when low pressure region is created, then normally wind flows to that area.

Answer 2

Causes Of Cyclones

Answer 3

Cyclones are caused due to the motion of winds at a high speed from a high pressure area to a low pressure land.
The sudden shift in atmospheric pressure causes Cyclones

Answer 4

There are many sorts of cyclones ragning from dust devils to hurricanes - the latter of which is among the least common. In Australia the term "cyclone" is often used synonymously with "typhoon", but strictly speaking a cyclone is any circulation of wind about a center which rotates in the same sense as the Earth's axis in that hemisphere - i.e., counterclockwise in the Northern Hemisphere and clockwise in the Southern.

Among the most common of cyclones are the Lows seen on synoptic scale weather maps - which are primarily caused by baroclinic instability. A zone of large temperature gradient exists and a low pressure disturbance forms along it. The circulation created amlifies the Low - further decreasing its pressure as compared to the surroundings and thus strengthening the cyclonic circulation around it. This is most often accompanied by a trof in the middle atmopshere slightly upstream, which creates a favorable environement for further development of the surface Low.

Most people are unaware of this term, so I searched for some pages regarding baroclinic instability so you can see what I refer to.

This one:

http://www.phys.ufl.edu/~bernard/met1010/chapter13-2_files/v3_document.htm

includes a simple illsutration of what I describe above (click on Baroclinic Instability link).

This one:

http://av.rds.yahoo.com/_ylt=A9ibyKC1L2NFiVcB6WhrCqMX;_ylu=X3oDMTBvdmM3bGlxBHBndANhdl93ZWJfcmVzdWx0BHNlYwNzcg--/SIG=1332rgvcr/EXP=1164214581/**http%3a//www.whoi.edu/science/PO/dept/scientist/biosketch/Pedlosky_12_824_Ch9.pdf

is a very technical discussion involving the physical equations.

Answer 5

Hot inland condition which creates low pressure areas in sea or in land causes cyclones. Cyclones bring in rain as well as destruction in their trail.

Answer 6

This Site Might Help You.

RE:
what is reason for cyclone?
i want to know

Answer 7

the deep depression in the sea.

Answer 8

A ''tropical cyclone'' is a storm system fueled by the heat released when moist air rises and the water vapor in it condenses. The term describes the storm's origin in the tropics and its cyclonic nature, which means that its circulation is counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. Tropical cyclones are distinguished from other cyclonic windstorms such as nor'easters, European windstorms, and polar lows by the heat mechanism that fuels them, which makes them "warm core" storm systems.

Depending on their location and strength, there are various terms by which tropical cyclones are known, such as hurricane, typhoon, tropical storm, cyclonic storm and tropical depression.

Tropical cyclones can produce extremely strong winds, tornadoes, torrential rain, high waves, and storm surges. They are born and sustained over large bodies of warm water and lose their strength over land; this explains why coastal regions can receive much damage while inland regions are relatively safe. The heavy rains and storm surges can produce extensive flooding. Although their effects on human populations can be devastating, tropical cyclones also can have beneficial effects by relieving drought conditions. They carry heat away from the tropics, an important mechanism of the global atmospheric circulation that maintains equilibrium in the earth's troposphere.

Physical structure

Structure of a hurricane

A strong tropical cyclone consists of the following components:

Surface low: All tropical cyclones rotate around an area of low atmospheric pressure near the Earth's surface. The pressures recorded at the centers of tropical cyclones are among the lowest that occur on Earth's surface at sea level.
Warm core: Tropical cyclones are characterized and driven by the release of large amounts of latent heat of condensation as 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.
Central Dense Overcast (CDO): The Central Dense Overcast is the shield of cirrus clouds produced by the eyewall thunderstorms. Typically, these are the highest and coldest clouds in the cyclone.

Eye: A strong tropical cyclone will harbor an area of sinking air at the center of circulation. Weather in the eye is normally calm and free of clouds (however, the sea may be extremely violent). The eye is normally circular in shape, and may range in size from 3 km to 320 km (2 miles to 200 miles) in diameter. In weaker cyclones, the CDO covers the circulation center, resulting in no visible eye.

Eyewall: A band around the eye of greatest wind speed, where clouds reach highest and precipitation is heaviest. The heaviest wind damage occurs where a hurricane's eyewall passes over land.

Rainbands: Bands of showers and thunderstorms that spiral cyclonically toward the storm center. High wind gusts and heavy downpours often occur in individual rainbands, with relatively calm weather between bands. Tornadoes often form in the rainbands of landfalling tropical cyclones. Annular hurricanes are distinctive for their lack of rainbands.

Outflow: The upper levels of a tropical cyclone feature winds headed away from the center of the storm with an anticyclonic rotation. Winds at the surface are strongly cyclonic, weaken with height, and eventually reverse themselves. Tropical cyclones owe this unique characteristic to the warm core at the center of the storm.

Formation

Factors in formation
Main article: Tropical cyclogenesis

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. Six factors appear to be generally necessary, although tropical cyclones may occasionally form without meeting all of these conditions:

Water temperatures of at least 26.5 °C (80°F)[9] down to a depth of at least 50 m (150 feet). Waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms

Rapid cooling with height. This allows the release of latent heat, which is the source of energy in a tropical cyclone

High humidity, especially in the lower-to-mid troposphere. When there is a great deal of moisture in the atmosphere, conditions are more favourable for disturbances to develop.[9]
Low wind shear. When wind shear is high, the convection in a cyclone or disturbance will be disrupted, preventing formation of the feedback loop

Distance from the equator. This allows the Coriolis force to deflect winds blowing towards the low pressure center, causing a circulation. The minimum distance is about 500 km (310 miles) or 5 degrees from the equator

A pre-existing system of disturbed weather. The system must have some sort of circulation as well as a low pressure center

This TRMM image shows the height of rain columns within Hurricane Irene.Generally, tropical cyclones generally form from four different types of systems: monsoon troughs, tropical waves, non-tropical lows, and decaying frontal boundaries. Monsoon troughs, which are broad areas of converging winds from both hemispheres, are the main trigger of tropical cyclone formation worldwide.

When they strengthen, either due to strengthening high pressure poleward of the trough or by increased flow passing through the equator from the opposite hemisphere, thunderstorm activity increases and tropical cyclogenesis can occur.

Another common mechanism for tropical cyclone formation are tropical waves, also called easterly waves, which are westward-moving areas of convergent winds. These generate most of the hurricanes in the Atlantic and northeast Pacific basins. Tropical waves often carry with them clusters of thunderstorms, which can then develop into tropical cyclones. A similar phenomenon to tropical waves are West African disturbance lines, which are squalls that form over Africa and move into the Atlantic, often as a part of the Intertropical Convergence Zone. Tropical cyclones also frequently form from upper tropospheric troughs, which are cold-core upper-level lows. A warm-core tropical cyclone may result when one of these works down to the lower levels of the atmosphere and produces deep convection. Off-season tropical cyclones most often form in this manner. Finally, decaying frontal boundaries may occasionally stall over warm waters and produce lines of active convection. If a low-level circulation forms under this convection, it may develop into a tropical cyclone.


Cumulative tracks of all cyclones from 1985 to 2005

Locations of formation

Most tropical cyclones form in a worldwide band of thunderstorm activity called by several names: the Intertropical Discontinuity (ITD), the Intertropical Convergence Zone (ITCZ), or the monsoon trough.

Most of these systems form between 10 and 30 degrees of the equator and 87% form within 20 degrees of it. 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. However, it is possible for tropical cyclones to form within this boundary as did Typhoon Vamei in 2001 and Cyclone Agni in 2004.


Major basins
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the Pacific Ocean (considered separately because tropical cyclones rarely form in the central Pacific), the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The North Atlantic is the most studied of the basins, while the Western Pacific is the most active and the North Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones (at least of Category 3 intensity).

There are six Regional Specialised Meteorological Centres (RSMCs) worldwide. These organizations are designated by the World Meteorological Organization and are responsible for tracking and issuing bulletins, warnings, and advisories about tropical cyclones in their designated areas of responsibility. Additionally, there are five Tropical Cyclone Warning Centres (TCWCs) that provide information to smaller regions.[15] The RSMCs and TCWCs, however, are not the only organizations that provide information about tropical cyclones to the public. The Joint Typhoon Warning Center (JTWC) issues informal advisories in all basins except the Northern Atlantic and Northeastern Pacific. The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) issues informal advisories, as well as names, for tropical cyclones that approach the Philippines in the Northwestern Pacific. The Canadian Hurricane Centre (CHC) issues advisories on hurricanes and their remnants that affect Canada.

Northern Atlantic Ocean: The most-studied of all tropical basins,[citation needed] it includes the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. Tropical cyclone formation here varies widely from year to year, ranging from over twenty to one per year with an average of around ten.[16] The United States Atlantic coast, Mexico, Central America, the Caribbean Islands, and Bermuda are frequently affected by storms in this basin. Venezuela, the south-east of Canada and Atlantic "Macaronesian" islands are also occasionally affected. Many of the more intense Atlantic storms are Cape Verde-type hurricanes, which form off the west coast of Africa near the Cape Verde islands. Rarely, a hurricane can reach western Europe, including Hurricane Lili, which dissipated over the British Isles in October 1996,[17] and Tropical Storm Vince, which made landfall on the southwestern coast of Spain in September 2005.
Northeastern Pacific Ocean: This is the second most active basin in the world, and the most dense (a large number of storms for a small area of ocean). Storms that form here can affect western Mexico, Texas, Hawaii, northern Central America, California, Arizona, and on rare occasions, Japan. No hurricane included in the modern database has reached California; however, historical records from 1858 speak of a storm that struck San Diego with winds over 75 m.p.h./65 kts, above hurricane force, though it is not known if the storm actually made landfall.Since 1900, only one system of tropial storm strength has made landfall in California.
Northwestern Pacific Ocean: Tropical storm activity in this region frequently affects China, Japan, Hong Kong, the Philippines, and Taiwan, but also many other countries in Southeast Asia, such as Vietnam, South Korea, and parts of Indonesia, plus numerous Oceanian islands. This is by far the most active basin, accounting for one-third of all tropical cyclone activity in the world. The coast of China sees the most landfalling tropical cyclones worldwide. The Philippines receives an average 18 typhoon landings per year. Rarely does a typhoon or an extratropical storm reach northward to Siberia, Russia.[citation needed]
Northern Indian Ocean: This basin is divided into two areas, the Bay of Bengal and the Arabian Sea, with the Bay of Bengal dominating (5 to 6 times more activity). This basin's season has an interesting double peak; one in April and May before the onset of the monsoon, and another in October and November just after

Tropical cyclones which form in this basin have historically cost the most lives — most notably, the 1970 Bhola cyclone killed 200,000. Nations affected by this basin include India, Bangladesh, Sri Lanka, Thailand, Myanmar, and Pakistan. Rarely, a tropical cyclone formed in this basin will affect the Arabian Peninsula.
Southwestern Pacific Ocean: Tropical activity in this region largely affects Australia and Oceania. On rare occasions, tropical storms reach the vicinity of Brisbane, Australia and into New Zealand, usually during or after extratropical transition.[20]
Southeastern Indian Ocean: Tropical activity in this region affects Australia and Indonesia. According to the Australian Bureau of Meteorology, the most frequently hit portion of Australia is between Exmouth and Broome in Western Australia.[21]
Southwestern Indian Ocean: This basin is the least understood, due to a lack of historical data.[citation needed] Cyclones forming here impact Madagascar, Mozambique, Mauritius, Reunion, Comoros, Tanzania, and Kenya.[citation needed]

[edit] Times of formation
Worldwide, tropical cyclone activity peaks in late summer when water temperatures are warmest. 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.

In the North Atlantic, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September. The statistical peak of the North Atlantic hurricane season is September 10. The Northeast Pacific has a broader period of activity, but in a similar time frame to the Atlantic. The Northwest Pacific sees tropical cyclones year-round, with a minimum in February 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

In the Southern Hemisphere, tropical cyclone activity begins in late October and ends in May. Southern Hemisphere activity peaks in mid-February to early March.

A tropical cyclone can cease to have tropical characteristics in several ways:

It moves over land, thus depriving it of the warm water it needs to power itself, and quickly loses strength. Most strong storms lose their strength very rapidly after landfall and become disorganized areas of low pressure within a day or two. There is, however, a chance they could regenerate if they manage to get back over open warm water. If a storm is over mountains for even a short time, it can rapidly lose its structure. However, many storm fatalities occur in mountainous terrain, as the dying storm unleashes torrential rainfall which can lead to deadly floods and mudslides.
It remains in the same area of ocean for too long, drawing heat off of the ocean surface until it becomes too cool to support the storm. Without warm surface water, the storm cannot survive.
It experiences wind shear, causing the convection to lose direction and the heat engine to break down.
It can be weak enough to be consumed by another area of low pressure, disrupting it and joining to become a large area of non-cyclonic thunderstorms. (Such, however, can strengthen the non-tropical system as a whole.)
It enters colder waters. This does not necessarily mean the death of the storm, but the storm will lose its tropical characteristics. These storms are extratropical cyclones.
Even after a tropical cyclone is said to be extratropical or dissipated, it can still have tropical storm force (or occasionally hurricane force) winds and drop several inches of rainfall. When a tropical cyclone reaches higher latitudes or passes over land, it may merge with weather fronts or develop into a frontal cyclone, also called extratropical cyclone. In the Atlantic ocean, such tropical-derived cyclones of higher latitudes can be violent and may occasionally remain at hurricane-force wind speeds when they reach Europe as a European windstorm, such as the extratropical remnants of Hurricane Iris in 1995

Guess you have the question answered!!!

Good luck