A cyclone is an area of low atmospheric pressure characterized by inward spiraling winds that rotate counter clockwise in the northern hemisphere and clockwise in the southern hemisphere of the Earth.
Cyclones are named variously in various regions :
A tropical cyclone is the general term for violent circular winds with torrential rains that originate in the tropics.
Hurricans is the term when they occur in the Atlantic Ocean
They are called typhoons in the Pacific Ocean.
They are called cyclones in the Indian Ocean.
Structure and Formation:
The structure of the cyclone consists of northern hemisphere, center and southern hemisphere. Usually a cyclone hits where there is low atmospheric pressure and the low atmospheric pressure are mostly found in tropical and sub-tropical regions.
Formation of cyclone:
Cold- core cyclones:
T hese cyclones form due to the motion of a cyclone. The pressure here increases upwards and low surface pressure.
It starts due to the upper pressure and as the cyclone forms it increases its strength.
Polar cyclone is a low pressure weather system usually spans up to 1,000 to 2,000kms in which the area circulates in a counter clockwise direction in northern hemisphere and clockwise in southern hemisphere.
This is found over ocean areas. It has a horizontal length scaling less than 1,000kms and exists no more than a couple of days. They are difficult to detect using conventional weather reports, which is hazardous for shipping, gas and oil plat forms.
Polar low over the Barents Sea on February 27 , 1987 Main article: Polar low
These cyclones have the characteristics of tropical cyclones. It can be formed in a wide band of latitude from the equator to 50 degrees.
A tropical cyclone is the storm system fueled by the heat released when moist air rises and the water vapour in it condenses.
This cyclone is found on mars by the Hubble space telescope. These are not unique to earth. These cyclones are common on Jovian planets like the small dark spots on Neptune,Mars.
Extraterrestrial: Cyclone on Mars, imaged by the Hubble Space Telescope
Andhra Pradesh with its large stretch of coast is recurrently prone to cyclones. Various communication and remote sensing satellite data are being actively used in developing early cyclone warning signal systems. As andhra pradesh is merged with different vegetations coastal plantations, mixed plantations, waste land, fallows. wet fallows, marshy lands, sand aquaculture, dense forests, degraded forest, mangroves and agriculture. These all are extracted from 9 districts of A.P located along the coast.
Major factors responsible for cyclone disaster:
Manifestation of humanity:
Manifestation of humanity overloading the earth’s ecology due to global warming is a reality that cannot be neglected. The human effect on the climate is the major factor leading to cyclone.
Ecological impacts are of various kinds like:
1:Use of land.
2:Use of water.
3:Effects on bio-diversity.
4:Use of non-renewable resources.
5:Production of green house gases.
6:Production of other un acceptable pollutants.
The destruction, during recent decades, of coastal forests removed a barrier which formerly mitigated the effects of waves and wind from cyclonic storms.
The standard of protection such as housing and infrastructure in an inappropriate way for a region subject to frequent intense cyclones. And for poor people, without savings or insurance, total loss turns a disaster into a catastrophe.
Prevention to be taken before a cyclone:
Keep a list of emergency phone numbers handy, including numbers for your local Police, Fire, Ambulance, State Emergency Service,etc..
Clear your property of any loose items that could become missiles during extreme winds (eg sheet iron and wood).
Find out how and where to turn off power, gas and water supplies.
Store your important documents (eg wills, passports, photos, birth certificates) in a fire/water-proof container or safe deposit box.
Check that you have adequate household and contents insurance and which hazards are not covered by the policy.
Prevention at the time when cyclone hits :
Disconnect all electrical appliances and turn off the gas .
Fuel your car and park it under solid cover.
Pack an evacuation kit including your emergency kit, warm clothing, essential medications, valuables, papers, photos and keepsakes in waterproof bags.
Stay inside and shelter in the strongest part of the building.
Continue to listen to your portable radio for updates and advice.
Beware of the calm 'eye' of the cyclone. If the wind suddenly drops, don't assume that the cyclone is over. Violent winds will soon resume from the opposite direction .
If you are driving, STOP - but well away from the sea and clear of trees, power-lines and watercourses. Stay in your vehicle.
Preventions to be taken after cyclone:
Don't go outside until officially advised it is safe to do so.
Check for gas leaks and don't use electrical appliances if wet.
Keep listening to your local radio for official warnings and advice.
If you did evacuate your home, don't return until advised.
Beware of fallen powerlines, damaged bridges, buildings and trees, and don't enter floodwaters.