Tropical cyclones origin causes

Describe the causes of origin, structure and weather associated with tropical cyclones.

Answer 

Tropical cyclones are powerful rotating storms that form over warm ocean water in tropical regions. Tropical cyclones are known by different names in different parts of the world. In the Atlantic Ocean and the eastern Pacific Ocean they are called hurricanes. In the western Pacific Ocean they are called typhoons. In the Indian Ocean and around Australia they are called tropical cyclones. All these storms are the same type of weather system. They are intense low pressure systems with strong winds heavy rain and dangerous storm surge. Understanding the causes of origin structure and weather associated with tropical cyclones is very important for disaster management and climate studies. Tropical cyclones are among the most destructive natural disasters in the world. The causes of tropical cyclones are linked to warm ocean water moist air low pressure and the Coriolis force. The structure of tropical cyclones includes the eye the eyewall and spiral rainbands. The weather associated with tropical cyclones includes heavy rainfall strong winds flooding and coastal storm surge. This article describes in detail the causes of origin structure and weather associated with tropical cyclones in easy words. The origin of tropical cyclones begins over warm tropical oceans. Warm ocean water is the main source of energy for tropical cyclones. When sea surface temperature is above twenty six degrees Celsius the water provides heat and moisture to the air above it. This heat energy is called latent heat. As warm moist air rises from the ocean surface it cools and condenses to form clouds. During condensation heat is released into the atmosphere. This released heat makes the air even warmer and lighter. The warm air continues to rise and creates a low pressure area near the ocean surface. The formation of a low pressure system is one of the main causes of tropical cyclones. When air rises in a low pressure area more air moves in from surrounding areas to fill the gap. This movement of air increases wind speed. If conditions are favorable the system becomes stronger and may develop into a tropical cyclone. Another important cause of tropical cyclone origin is the Coriolis force. The Coriolis force is caused by the rotation of the Earth. It makes moving air turn to the right in the northern hemisphere and to the left in the southern hemisphere. This turning motion helps the storm to spin and develop a circular rotation. Without the Coriolis force tropical cyclones cannot form. That is why tropical cyclones do not form near the equator because the Coriolis force is very weak there. Tropical cyclones usually form between five and twenty degrees latitude north and south of the equator. Low vertical wind shear is also necessary for the formation of tropical cyclones. Wind shear means a change in wind speed or wind direction with height. If wind shear is strong it can break apart the developing storm. If wind shear is weak the storm can grow vertically and become organized. Moist air in the middle levels of the atmosphere is another important factor. 

Dry air can weaken a developing system

When the atmosphere is moist the storm clouds can grow higher and stronger. A pre existing disturbance is often needed to start the process. This disturbance can be a tropical wave or a low pressure trough. When such a disturbance moves over warm ocean water it can begin to organize and strengthen. The stages of development of tropical cyclones are important in understanding their origin. First a tropical disturbance forms. This is a cluster of thunderstorms over warm water. If the disturbance becomes more organized and winds increase it becomes a tropical depression. A tropical depression has wind speed less than sixty three kilometers per hour. When wind speed increases to between sixty three and one hundred eighteen kilometers per hour it becomes a tropical storm. At this stage the storm is given a name. When wind speed reaches one hundred nineteen kilometers per hour or more it becomes a tropical cyclone or hurricane or typhoon depending on the region. The structure of tropical cyclones is very special and organized. A mature tropical cyclone has three main parts. These parts are the eye the eyewall and the spiral rainbands. The eye is the center of the storm. It is a circular area of calm weather and clear skies. The eye usually has a diameter of twenty to forty kilometers. In the eye the air is sinking which creates calm conditions. Around the eye is the eyewall. The eyewall is the most dangerous part of the storm. It contains the strongest winds and heaviest rainfall. The clouds in the eyewall are very tall and thick. These clouds are called cumulonimbus clouds. The spiral rainbands extend outward from the eyewall. These rainbands are curved lines of clouds and thunderstorms. They bring heavy rain and strong winds to areas far from the center of the storm. The structure of tropical cyclones is like a giant heat engine. Warm air rises near the center and cold air sinks at the top. Air flows outward at high levels of the atmosphere. This circulation pattern allows the storm to maintain its strength as long as it stays over warm water. The pressure at the center of a tropical cyclone is very low. 

The lower the central pressure 

the stronger the storm. The difference in pressure between the center and the surrounding area creates strong winds. These winds rotate around the eye in a circular pattern. In the northern hemisphere the rotation is counterclockwise. In the southern hemisphere the rotation is clockwise. The size of tropical cyclones can vary. Some storms are small and compact. Others are very large and can cover hundreds of kilometers. The weather associated with tropical cyclones is severe and dangerous. One of the main weather features is strong wind. Wind speed in a powerful tropical cyclone can exceed two hundred kilometers per hour. These strong winds can damage buildings uproot trees and destroy power lines. Another major weather effect is heavy rainfall. Tropical cyclones can produce very heavy rain over a short period of time. This heavy rainfall can cause flash floods and river floods. Flooding is often the most deadly effect of tropical cyclones. Storm surge is another dangerous weather event associated with tropical cyclones. Storm surge is a rise in sea level caused by strong winds pushing water toward the coast. When a tropical cyclone makes landfall the storm surge can flood coastal areas. Storm surge can destroy homes roads and bridges. It can also cause loss of life. High waves are also produced by tropical cyclones. These waves can damage ships and coastal structures. Tornadoes can sometimes form in the outer rainbands of tropical cyclones. These tornadoes add to the destruction. The weather associated with tropical cyclones also includes thunderstorms lightning and very low pressure. As the storm moves inland it usually becomes weaker because it loses its source of warm ocean water. Friction with land also slows down the winds. However heavy rain and flooding can continue even after the storm weakens. The movement of tropical cyclones depends on large scale wind patterns. They are often steered by trade winds in the tropics. As they move to higher latitudes they may turn toward the east due to westerly winds. Some tropical cyclones move slowly and cause prolonged rainfall. Others move quickly and affect large areas in a short time. Climate change and global warming may influence tropical cyclones. Warmer ocean temperatures can provide more energy to storms. Some studies suggest that the intensity of tropical cyclones may increase in a warming climate. However the total number of storms each year may not increase significantly. Monitoring and forecasting tropical cyclones is very important. Meteorological departments use satellites weather radars and computer models to track storms. 

Early warning systems 

help people to prepare and evacuate if necessary. Preparedness can reduce the damage and loss of life caused by tropical cyclones. In summary the causes of origin of tropical cyclones include warm ocean water low pressure moist air low wind shear and the Coriolis force. The structure of tropical cyclones includes the eye the eyewall and spiral rainbands. The weather associated with tropical cyclones includes strong winds heavy rainfall storm surge flooding and high waves. Tropical cyclones are powerful natural systems that act like giant heat engines over warm oceans. They form in tropical regions where sea surface temperatures are high. They weaken over land or cool water. Understanding tropical cyclones is important for geography students disaster management authorities and climate scientists. Tropical cyclones show the strong connection between the ocean and the atmosphere. They demonstrate how heat energy from warm water can be converted into wind and rain. The study of tropical cyclones helps in improving weather forecasting and saving lives. Tropical cyclones will continue to affect coastal regions around the world. Awareness education and scientific research are key to reducing their impact. The causes structure and weather associated with tropical cyclones are important topics in physical geography and environmental studies. By learning about tropical cyclones we can better prepare for hurricanes typhoons and severe storms in the future.