Cyclone
- 3. I would like to thank my Social studies teacher Sunita Mam and my group members for helping me in making this presentation. My group members helped me in editing of this presentation. My parents helped me in formatting the matter of the presentation. I collected the information from the internet and from some books.My other gratitude I would like to convey to my school who suggest me to make this and to have
- 6. CYCLOGENESI SCyclogenesis describes the process of cyclone formation and intensification. Extra tropical cyclones form as waves in large regions of enhanced mid- latitude temperature contrasts called baroclinic zones.
- 7. Baroclinic zones contract to form weather fronts as the cyclonic circulation closes andintensifies. Later in theirlife cycle, cyclones occlude as coldcore systems. A cyclone's track is guidedover the course of its 2 to 6 day life cycle by the steering flow of the cancer or subtropical jet stream. Weather fronts separate two masses of air of different densities andare associatedwith the most prominent meteorological phenomena. LIFE CYCLE OF CYCLONE
- 8. Air massesseparated by a front may differin temperatureor humidity. Strongcold frontstypicallyfeaturenarrowbandsof thunderstorms and severeweather, and may on occasionbe precededby squalllinesor dry lines. Theyformwest of thecirculationcenter and generally movefromwest to east.Warmfrontsformeast of thecyclonecenterand are usuallyprecededby stratiformprecipitationand fog. Theymove polewardaheadof the cyclone path. Occluded frontsformlate in thecyclonelife cycle nearthe centerof the cycloneand oftenwraparoundthe stormcenter. Tropical cyclogenesisdescribesthe processof developmentof tropical cyclones. Tropical cyclonesformdue to latentheat drivenby significant thunderstormactivity, and arewarmcore. Cyclonescantransition betweenextratropical, subtropical, and tropicalphasesunderthe rightconditions. Mesocyclonesformas warmcore cyclonesover land, and canleadto tornado formation. Waterspoutscanalsoformfrommesocyclones, but moreoftendevelopfrom environmentsof highinstabilityandlowverticalwindshear.
- 9. The main features of a cyclone are: the eye, the eye wall and rain bands. The eye is situated at the very centre of a cyclone and is a region of mostly calm weather. Surrounding this is the eye wall, a ring of towering thunderstorms where the most severe weather occurs. Rain bands are compact regions of vertical air movement, which spiral into the centre of the cyclone.
- 10. There are a number of structural characteristics common to all cyclones. A cyclone is a low-pressure area. A cyclone's center (often known in a mature tropical cyclone as the eye), is the area of lowest atmospheric pressure in the region. Near the center, the pressure gradient force(from the pressure in the center of the cyclone compared to the pressure outside the cyclone) and the force from the Coriolis effect must be in an approximate balance, or the cyclone would collapse on itself as a result of the difference in pressure. Because of the Coriolis effect, the wind flow around a large cyclone is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Cyclonic circulation is sometimes referred to ascontra solem. In the Northern Hemisphere, the fastest winds relative to the surface of the Earth therefore occur on the eastern side of a northward-moving cyclone and on the northern side of a westward-moving one; the opposite occurs in the Southern
- 11. In the Atlantic and the northeastern Pacific oceans, a tropical cyclone is generally referred to as a hurricane(from the name of the ancient Central American deity of wind, Huracan), in the Indian and south Pacific oceans it is called a
- 12. The initial extra tropical low-pressure area forms at the location of the red dot on the image. It is usually perpendicular to the leaf-like cloud formation seen on satellite during the
- 13. Tropical cyclones form when the energy released by the condensation of moisture in rising air causes a positive feedback loop over warm ocean waters. Cyclones are made from a simple thunderstorm, with full cooperation from both the ocean and the atmosphere. The water in the ocean must be warmer than 26.5 degrees Celsius. The moisture and the heat from this hot water is the ultimate source for cyclones.
- 14. Anextratropicalcycloneis a synoptic scalelow-pressure weather system that does not have tropical characteristics, being connectedwithfrontsand horizontal gradients in temperature anddew point otherwise knownas "baroclinic zones". Thesesystemsmay alsobe describedas "mid-latitude cyclones" due to their area of formation, or "post-tropical cyclones"where extratropical transitionhas occurred, andare oftendescribedas" depressions"or "lows" by weather forecasters andthe generalpublic. Theseare the everyday phenomena which alongwith anti-cyclones, drive the weather over much of the Earth.
- 15. Althoughextratropical cyclones are almost always classified as baroclinic since they formalong zones of temperature and dew pointgradient withinthe wester lies, they can sometimes become barotropiclate in their life cycle whenthe temperature distributionaround the cyclone becomes fairly uniformwithradius. An extratropical cyclone can transformintoa subtropical storm, and fromthere intoa tropical cyclone, if it dwells over warmwaters and develops central convection, whichwarms its core. One intensetype of extratropical cyclone that strikes during wintertime is anor'easter.
- 16. 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 between the equator and the 50th parallel. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical cyclones or extratropical cyclones, and used terms such as quasi-tropical and semi- tropical to describe the cyclone hybrids. By 1972, the National Hurricane Center officially recognized this cyclone category. Subtropical cyclones began to receive names off the official tropical cyclone list in the Atlantic Basin in 2002. They have broad wind patterns with maximum sustained winds located farther from the center than typical tropical cyclones, and exist in areas of weak to moderate temperature gradient. Since they form from initially extratropical cyclones which have colder temperatures aloft than normally found in the tropics, the sea surface temperatures required for their formation are lower than the tropical cyclone threshold by three degrees Celsius, or five degrees Fahrenheit, lying around 23 degrees Celsius.` SUBTROPICAL CYCLONE
- 17. The following types of cyclones are not identifiable in synoptic charts. Mesocyclone A Mesocyclone is a vortex of air, 2.0 kilometres (1.2 mi) to 10 kilometres (6.2 mi) in diameter (the mesoscale of meteorology), within a convective storm. Air rises and rotates around a vertical axis, usually in the same direction as low-pressure systems in both northern and southern hemisphere. They are most often cyclonic, that is, associated with a localized low-pressure region within a super cell. Such storms can feature strong surface winds and severe hail. Mesocyclones often occur together with updrafts in super cells, where tornadoes may form. About
- 18. A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. Also referred to as twisters, a colloquial term in America, or cyclones, although the word cyclone is used in meteorology, in a wider sense, to name Tornado
- 19. A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a metre wide and a few metres tall) to large (more than 10 metres wide and more than 1000 metres tall). The primary vertical motion is upward. Dust devils are usually harmless, but can on rare Dust Devil
- 20. A waterspout is a columnar vortex forming over water that is, in its most common form, a water that is connected to a cumuliform cloud. While it is often weaker than most of its land counterparts, stronger versions spawned by mesocyclones do occur. Steam devil A gentle vortex over calm water or wet landmade visible by rising water vapour. Water Spout
- 21. Cyclones can produce extremely powerful winds and torrential rain, they are also able to produce high waves and damaging storm surge. They develop over large bodies of warm water, and lose their strength if they move over land. This is the reason 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 also relieve drought conditions. As a result, tropical cyclones help to maintain equilibrium in the Earth's troposphere.
- 24. Cyclone Nargis is the deadliest tropical stormin the recorded history of Burma (Myanmar). It devastated many areas in Burma, as well as some areas in Sri Lanka, Bangladesh and India. NARGIS
- 25. Cyclone Nargis caused catastrophic destruction to the Burmese landscape. Thousands of buildings have been flattened, power lines downed, trees uprooted, roads blocked and water supplies disrupted. IMPACT ON LANDSCAPES
- 26. It was extremely hard for the emergency responses to help the people in Burma because the government would not let anyone into the country. Even when they eventually did gain entry into the country, the government insisted on distributing aids by themselves. EMERGENCY RESPONSES