TROPICAL CYCLONES

CLASS 9 SOCIAL STUDIES PROJECT WORK F.A.-3, TOOL-1

WHAT ARE CYCLONES ? Cyclone refers to any spinning storm that rotates around a low-pressure center. The low-pressure center is also referred to as the 'eye' of the storm, which is well known for being eerily calm compared with the areas under the spinning 'arms' of the storm. Here are the types of cyclones :

Tropical cyclones

Polar cyclones

Mesocyclones

IN THIS POWER POINT PRESENTATION WE ARE GOING TO DISCUSS IN DETAIL ABOUT TROPICAL CYCLONES.WHAT IS TROPICAL CYCLONE ?A TROPICAL CYCLONE IS AN INTENSE LOW PRESSURE AREA OR A WHIRL IN THE ATMOSPHERE OVER TROPICAL AND SUB-TROPICAL WATERS• WITH ORGANISED CONVECTION I.E. THUNDERSTORM ACTIVITY • WINDS AT LOW LEVELS, CIRCULATING ANTI-CLOCKWISE IN THE NORTHERN HEMISPHERE

AND CLOCKWISE IN THE SOUTHERN HEMISPHERE• PRESSURE INCREASES OUTWARDS FROM THE CENTRE OF A CYCLONIC STORM. • THE AMOUNT OF THE PRESSURE DROP IN THE CENTRE AND THE RATE AT WHICH IT

INCREASES OUTWARDS GIVES THE INTENSITY OF THE CYCLONES AND THE STRENGTH OF WINDS.

Mechanism of tropical cyclonesA source of warm, moist air derived from tropical oceans with sea surface temperature normally near to or in excess of 27 degrees C.

Winds near the ocean surface blowing from different directions converge and cause air to rise and storm to form clouds.

Winds which do not vary greatly with height are known as low wind shear. This allows the clouds to rise vertically to high levels.

Coriolis force i.e. the spin induced by the rotation of the earth is one of the main factor. Once a cluster of storm clouds start to rotate, it becomes a tropical depression. If it continues to develop it becomes a tropical cyclone and later a cyclone.

This map represents the states of India and the level of impact affected by all of the states. The following represents:

Deep red – Most vulnerableRed and pink – Average impactYellow – Low impact

Factors that contribute to cyclones A fall in the atmospheric pressure over the sea surface Effect of the wind Influence of the sea bed A funneling effect The angle and speed at which the storm approaches the coast The tides

EFFECTS OF CYCLONESTHE MAIN EFFECTS OF TROPICAL CYCLONES INCLUDE HEAVY RAIN, STRONG WIND, LARGE STORM SURGES AT LANDFALL, AND TORNADOES. THE DESTRUCTION FROM TROPICAL CYCLONE DEPENDS MAINLY ON ITS INTENSITY, SIZE AND LOCATION.

They harm the ecosystem of the surrounding region.

Civic facilities and communication systems are disturbed.

They causes harm to plant human and animal life.

Agricultural land is severely affected, especially in terms of water supply and soil erosion

They cause damage to the life and the property of the people and the government

Weather phenomenon are studied with the following processes and instruments:1. Surface level observations: Helps to find out the pressure, temperature, density and viscosity with altitude in the Earth’s atmosphere. Surface weather observations are taken at airports for safety concerns during takeoffs.

2. Upper level observations: Helps to find the rate of atmospheric pressure, temperature, humidity and wind speed. Pilots and air force are benefitted from this upper level observations.

3. Single Stevenson screen: The purpose of this is to provide a standardized environment to measure temperature, humidity, dew point and atmospheric pressure.

4. Thermo-Hygrograph: Measures and records both temperature and humidity or dew point. Thermo means temperature and Hygro means Humidity. It measure the maximum and minimum temperature in a day.

5. Self recording rain gauge: It measures the amount of precipitation in a certain amount of time. It is nothing but it measures rainfall. It is measured in millimeters.

6. Open pan evapori meter: This instrument measures the rate of evaporation in a particular area. Open pan evapori meter measurements enable farmers and ranchers to understand how much water their crops need. This helps to increase the rate of production.

If I were a fisherman in the coast of Machilipatnam :I am a fishermen in Machilipatnam, a place frequently affected by cyclones. My income wholly depends on fishing. Fishing is a very risky occupation. Whenever we go to sea we never think whether we can return safely, so we should be very careful. I frequently watch and listen weather forecasts through radio and television. Now a days due to the technological development, we have got fishing apps which help us to know the sea movements. We even get alerts from the government. Everyday before going to fishing all the fishermen get to gather to discuss about the sea condition so that illiterates and people who can’t avail such facilities can also be benefitted. The precautions we take during cyclones :1.We don’t go for fishing during cyclones. We go for fishing, only if we come to know that there is no danger in fishing.2.We keep a note of all the warnings given by the Meteorological Department.3.We keep emergency phone numbers of police, ambulance and fire brigade handy.4.We vacate the place immediately if the condition of the cyclone is worse.

If I were a pilot in Visakhapatnam :I am posted as a pilot in Vizag, the first place affected by the deadly Hudhud cyclone.Air transport is the most comfortable and fastest means of transport. Air transport is uncertain and unreliable as it is controlled to a great extent by weather conditions. There are many flight accidents taking place. To avoid this, the government takes many precautions. We receive online real-time data on weather updates on-board a flight with from the Aviation Weather Observation System. We receive weather and turbulence forecasts once aloft, we get periodic updates from the meteorologists and we have a weather radar in the cockpit. We should attend the classes in India Meteorological Department to interpret the weather forecast code.

Precautions to be taken by us during cyclones : 1.If the cyclone is going to hit the plane, we should not panic, instead find the way to escape the cyclone and listen to the alerts carefully.2.Give instructions to the passengers not to panic and prepare them to handle the safety kit.

If I were a resident in the low lying area of Orissa :I am a resident in the low lying area of Orissa, a place lashed by cyclones. I need to be very careful and cautious to avoid the destruction of life and property. To know the weather conditions I read day to day weather forecast from newspapers and also watch television. I am very thankful to the India Meteorological Department which sends SMS to those who register their names in the official website.Precautions we take during cyclones :1.We do not venture outside until we are advised to do so.2.We keep a stock of non perishable food items and fill water in buckets and cover them.3.We keep listening to the media for regular updates.4.Based on the predicted wind and storm surge heights, we may evacuate the place if necessary.

If I were a community rescue worker in West Bengal : I am a community rescue worker in West Bengal, a place lashed by cyclones. I work for the society. West Bengal is often hit by cyclones. To know the weather conditions in this place I go with media (radio, t.v., newspaper). I have internet facility at my home. I opt online weather forecast. Our Association gets alerts from the India Meteorological Department. Precautions taken by us during cyclones :1.We should ensure that all the people in the community know that cyclone is going to hit the place.2.We take immediate steps shall be taken to conduct mock drill in every cyclone and flood shelter.3.In worst conditions we should be able to evacuate everyone from the place.

DO’S AND DON’S DURING CYCLONESDo’s1.We should regularly listen to weather bulletins on television and radio.2.It is necessary to have an emergency kit ready at home.3.We should ensure that the house is strong enough to face the cyclone.4.We should have the phone numbers of hospitals, police, help agencies, relatives, friends.5.We should store enough non-perishable food items in waterproof bags.6.We should disconnect all the electrical appliances.7.Based on the predicted wind and storm surge heights, an evacuation may be necessary.

Don’ts1.We should not venture outside especially into sea.2.We should avoid being mislead by rumors.3.Don’t touch the loose and dangling wires as it may lead to current shocks.4.We should not ignore warnings and avoid sightseeing.

Field trip questionnaire1.What are the different types of parameters? Wind speed and direction, air temperature, air pressure, air humidity, precipitation, haze and contents of the air, solar and terrestrial radiation. 2.What is the difference between forecast and nowcast?Forecast :Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location in advance. Nowcast : A description of present weather conditions along with a short-term forecast is called nowcast.3.Name the instrument used to record the variation in humidity and temperature?Hygrometer 4.Why is Hydrogen used in place of Helium in balloons for upper level observations?Helium’s non-flammable nature makes it the only practical lifting gas for manned lighter-than-air flight. But it is scarce and expensive. On the other hand,

hydrogen is the earth’s lightest element and can be manufactured easily and is inexpensive. So hydrogen used in place of helium in balloons for upper level observations.5.Upper level observations are made in the Troposphere. Why?The troposphere is the lowest layer of Earth's atmosphere. The troposphere starts at Earth's surface and goes up to a height of 7 to 20 km. Most of the mass of the atmosphere is in the troposphere. Almost all weather occurs within this layer. Air is warmest here. Higher up it gets colder. Air pressure and the density of the air are also less at high altitudes. This helps the balloon to raise and make observations.6.Name the different surface level observation instruments.Maximum and minimum thermometers, Anemometer and wind vane, Dry and Wet bulb thermometer, Rain gauge and Barometer.7.How is Hydrogen gas produced in Meteorological Department?Hydrogen Gas is produced and supplied to all stations in upper air network of IMD, in cylinders of various sizes. It is produced in the Hydrogen Generation Factory. Ferro Silicon, Caustic Soda and water are used in this process.

8.What is the full form of RADAR?Radio Detection And Ranging9.List the conditions necessary for installing the RADAR stations.The RADAR station should be installed 30mts away from ground. There should be no obstruction stopping the electromagnetic waves. Direction is also an important condition.1o.Draw a flow chart showing the working of RADAR.

11.How surface level and upper level observations help?Surface level observations: It helps to find out the pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere. Surface weather observations are taken at airports due to safety concerns during takeoffs and landings.Upper level observations: It helps to find the rate of atmospheric pressure, temperature, humidity and wind speed. Pilots and air force are benefitted from this upper level observations.

12.In what ways information gathered through RADAR helps us?Information given by RADAR is used in the detection of ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. RADAR is used by airport to ensure the safety of planes and helps to track cyclones.

13.How many observations are made in surface level per day both manually and automatically?Manually: 8 observationsAutomatically: observations

14.What is the extent of troposphere at the poles and at the equator?At poles: About 8kms At equator: About 20kms15.Which part in human body is used in making the string in Hydrograph?Human hair16.Why Stevenson Screen is kept away from sunlight?Stevenson screens are always installed facing north to keep the sun from shining directly on the thermometers and affecting the readings. If this instrument is installed in the east(sun rises) or in the west(sun sets) direction there may be a increase in the temperature.17.What are the advantages of automated measurements over manual observations?Automated observations Manual observationsNo labour is required. Labour is essential to take observations.Very accurate. Not very accurate.

18.How many weather balloons are launched by IMD on a daily basis?Two weather balloons are launched by IMD per day.19.What is the total expenditure involved in launching weather balloons?Rupees 10,00020.Why is the government spending huge amounts of money for weather forecast?‘Life is more valuable than anything.’ The main aim of government is to protect the valuable lives of the people. Money as a resource can be brought back with the help of human resource. But we can’t replace the life of human being with anything. To protect the human lives from natural calamities such as cyclones, tornadoes, earthquakes, tsunamis etc. government is spending huge amounts of money for weather forecast. Because of this government’s initiative we are able to save millions of lives.

BibliographyI have used the following websites to do this projectIndia Meteorological Department

websiteWikipediaCyclone center websiteBritannicaI referred ‘Natural Disasters’ book.

Done by S. Keerthana