What is meteorology?

• Meteorology is the science that studies atmospheric phenomena, especially those that relate to weather. Meteorologists who forecast the weather rely on thousands of weather stations located around the world, both on land and at sea.

HISTORYIn Bible times - "˜You are able to interpret the appearance of the sky but the sign of the times you

cannot interpret.” Book of Matthew

1441 -King Sejong’s son, Prince Munjong, invented the first standardized rain gauge

1450 - Leone Battista Alberti developed a swinging-plate anemometer, and is known as the first anemometer.

1607 - Galileo Galilei constructs a thermoscope

1643 -Evangelista Torricelli invented the barometer,Torricelli noticed that air pressure changes in accordance with changes in the weather. In fact a drop in pressure would often signal that a storm was coming.

1644 - hygrometer was invented

1662 - Sir Christopher Wren invented the mechanical, self-emptying, tipping bucket rain gauge.

1714 – Daniel Gabriel Fahrenheit invented the mercury thermometer

1742 - Anders Celsius, a Swedish astronomer, proposed the 'centigrade' temperature scale, the predecessor of the current Celsius scale

1765 - daily measurements of air pressure, moisture content, wind speed and direction began to be made. This was first done by French scientist Laurent Lavoisier who stated,"With all of this information it is almost always possible to predict the weather one or two days ahead with reasonable accuracy.”

1783 - the first hair hygrometer is demonstrated by Horace-Bénédict de Saussure.

1806 - Francis Beaufort introduced his system for classifying wind speeds

1854 - French warship and 38 merchant vessels sank in a fierce storm off the Crimean port of Balaklava

April 1960 - launch of the first successful weather satellite, TIROS-1, marked the beginning of the age where weather information became available globally.

ELEMENTS OF ELEMENTS OF METEOROLOGYMETEOROLOGY

CloudsCloudsRainRainWindWindHumidityHumidityInstrumentsInstruments

CloudsClouds

The cloudy part of the atmosphere lies below an The cloudy part of the atmosphere lies below an invisible ‘lid’ called the tropopause. Clouds invisible ‘lid’ called the tropopause. Clouds cannot penetrate this top that is put on the cannot penetrate this top that is put on the weather and about the only time when we weather and about the only time when we actually can see its effect is when thunderclouds actually can see its effect is when thunderclouds spread their anvils under it. The layer below the spread their anvils under it. The layer below the tropopause is called the troposphere and all tropopause is called the troposphere and all weather processes of interest to us occur in the weather processes of interest to us occur in the troposphere.troposphere.

Rain

Rain is the precipitation of l iquid drops of water. There are also other forms of precipitation such as snow, sleet and hail. Raindrops generally have a diameter greater than 0.5 mm (0.02 in). They range in size up to about 3 mm (about 0.13 in) in diameter, and their rate of fall increases, up to 7.6 m (25 ft) per sec with their size.

There are generally three types of rainfall: orographic rain (also known as relief rain), convectional rain and frontal/cyclonic rain.

Types of rainfall

What are the different types of rain and where do they happen?

How it rains

1. Warm air rises

2. Air cools

3. Condensation

4. Clouds form

5. Rain

1. 1. Relief RainRelief Rain

2. Forced to rise over the mountains

1. Warm moist air from the sea

3. Air cools as it is 3. Air cools as it is forced to riseforced to rise

4. Condensation

5. Clouds form

6. Rain

2. Convectional Rain

1. The sun heats the ground which heats the air

2. Warm air rises

4. Air cools as it is forced to rise

5. Condensation

6. Clouds form

7. Rain

3. 3. Frontal RainFrontal Rain

1. Mass of warm 1. Mass of warm air meets a air meets a mass of colder mass of colder airair

2. Lighter warm air rises over heavier cold air

3. Warm air cools3. Warm air cools

4. Condensation

5. Clouds form

6. Rain

WindWind

- is air in motion. - is air in motion. - It is usually the natural horizontal motion It is usually the natural horizontal motion

of the atmosphere. of the atmosphere. - Winds are produced by differences in Winds are produced by differences in

atmospheric pressure,.atmospheric pressure,.

Breeze Breeze 

important factors in a location's prevailing important factors in a location's prevailing winds. winds.

Sea breeze – movement of wind from sea to Sea breeze – movement of wind from sea to land that occurs during daytimeland that occurs during daytime

Land breeze – movement of air from land to Land breeze – movement of air from land to sea that occurs during night timesea that occurs during night time

HumidityHumidity

Humidity is the measurement of the water Humidity is the measurement of the water vapour content in the atmosphere. As water vapour content in the atmosphere. As water evaporates from lakes, seas and oceans and evaporates from lakes, seas and oceans and vegetation loses water through transpiration, the vegetation loses water through transpiration, the humidity of the air increases.humidity of the air increases.

The relative humidity of the air (ratio of the The relative humidity of the air (ratio of the amount of water vapour in the air to the amount of water vapour in the air to the maximum amount of water vapour the air can maximum amount of water vapour the air can contain expressed as a percantage) is contain expressed as a percantage) is measured using a measured using a hygrometerhygrometer..

Effects of humidityEffects of humidityAnimals and plantsAnimals and plants

Humidity is one of the fundamental abiotic factors that defines any Humidity is one of the fundamental abiotic factors that defines any habitat, and is a determinant of which animals and plants can thrive habitat, and is a determinant of which animals and plants can thrive in a given environment. in a given environment. Human comfortHuman comfort

Humans are sensitive to humid air because the human body uses Humans are sensitive to humid air because the human body uses evaporative cooling as the primary mechanism to regulate evaporative cooling as the primary mechanism to regulate temperature. temperature. ElectronicsElectronics

Many electronic devices have humidity specifications, for example, Many electronic devices have humidity specifications, for example, 5% to 95%. At the top end of the range, moisture may increase the 5% to 95%. At the top end of the range, moisture may increase the conductivity of permeable insulators leading to malfunction. conductivity of permeable insulators leading to malfunction. Building constructionBuilding construction

Traditional building designs typically had weak insulation, and it Traditional building designs typically had weak insulation, and it allowed air moisture to flow freely between the interior and exterior allowed air moisture to flow freely between the interior and exterior

InstrumentsThe anemometer measures  the 

wind  speed.  It  has  three  or  four horizontal  arms  pivoted  on  a vertical  shaft.  Metal  cups  are fixed  to  the  end  of  the  arms  so that when there is wind, the arms rotate.  The  movements  are transmitted  to  the  meter  which records the wind speed in meters per second or km per hour or  in knots (1.85km/h). 

Barometer

 a class of instruments used to measure atmospheric pressure.

 

HygrometerHygrometer A A hygrometerhygrometer  is made up of a  is made up of a

dry bulb thermometer and a wet dry bulb thermometer and a wet bulb thermometer. The dry bulb bulb thermometer. The dry bulb thermometer is an ordinary liquid-thermometer is an ordinary liquid-in-glass thermometer which in-glass thermometer which measures the actual temperature measures the actual temperature of the air. The wet bulb of the air. The wet bulb thermometer is the same as the thermometer is the same as the dry bulb thermometer, except that dry bulb thermometer, except that it is wrapped with a piece of muslin it is wrapped with a piece of muslin cloth which is kept moist by a cloth which is kept moist by a piece of wick dipped in water.piece of wick dipped in water.

Rain GaugeRain Gauge A rain gauge consists of an outer 13cm A rain gauge consists of an outer 13cm

diameter cylinder and an inner cylinder diameter cylinder and an inner cylinder with a jar. Rain is collected in the jar by with a jar. Rain is collected in the jar by means of a funnel which has a tapered means of a funnel which has a tapered end so that rain cannot easily evaporate.end so that rain cannot easily evaporate.

The rain gauge is sited in open space to The rain gauge is sited in open space to receive rain from all angles. It must be receive rain from all angles. It must be located away from buildings and trees located away from buildings and trees that may shelter the raindrops. It is sunk that may shelter the raindrops. It is sunk into the ground for stability and its rim is into the ground for stability and its rim is 30cm from the ground to prevent water 30cm from the ground to prevent water from splashing into it from the ground.from splashing into it from the ground.

Rainfall collected in the rain gauge is Rainfall collected in the rain gauge is then measured using a measuring then measured using a measuring cylinder.cylinder.

Sunshine Recorder

The sunshine recorder records  the  duration of  sunshine  at  a  place  for  a  day.  A glass  ball with a 10 cm diameter  is mounted on a metal frame.  This  glass  ball  focuses  the  sunshine  a sensitised  card  that  is  placed  below  it  on  the metal frame. The sunrays make burn marks on the  card.  Continuous  burn  marks  show continuous  sunshine.  Broken  marks  show otherwise.  At  the  end  of  the  day,  the  card  is removed and the burn marks are totalled to get the  total  duration  of  sunshine  for  the  day  in hours  and  minutes.  Lines  drawn  through places  having  the  same  amount  of  sunshine are called isohels. 

Thermometers• Maximum Thermometer     contains mercury with a high boiling point and it 

measures the maximum temperature of the day. The mercury in the thermometer expands and pushes the index up the tube when the day temperature increases. However, when the temperature drops, the mercury contracts, the index remains in position. The maximum temperature is thus recorded and the reading is taken at the end of the index closer to the mercury. The instrument is reset by using a magnet to draw the index back to the mercury.

• Minimum Thermometer      contains alcohol with a low freezing point and it 

records the minimum temperature of the day. The alcohol contracts and menicus of the alcohol pushes the index down when the temperature drops. When the temperature increases, the alcohol in the tube expands, flows past the index but does not move it.The minimum temperature is obtained by reading the scale at the end of the index which is near the minicus. The instrument is reset using a magnet to draw the index up to the menicus. 

Wind VaneWind Vane• The The wind vanewind vane  consists of  consists of

a pointer that moves freely a pointer that moves freely on a vertical shaft. The four on a vertical shaft. The four cardinal points are tied to cardinal points are tied to the shaft beneath the the shaft beneath the pointer. When the wind pointer. When the wind blows, the pointer moves blows, the pointer moves and its head shows the and its head shows the direction from which the direction from which the wind is blowing. The arrow wind is blowing. The arrow of the wind vane always of the wind vane always points in the direction from points in the direction from the wind blows and the the wind blows and the wind is named after this wind is named after this direction.direction.

APPLICATIONAPPLICATION

Weather ForecastingWeather ForecastingAviation MeteorologyAviation MeteorologyAgricultural MeteorologyAgricultural MeteorologyHydrometeorologyHydrometeorologyNuclear MeteorologyNuclear MeteorologyMaritime MeteorologyMaritime Meteorology

1st Step: Observation

2nd Step: Collection And Transmission Of Weather Data

3rd Step: Plotting Of Weather Data

4th Step: Analysis Of Weather Maps, Satellite And Radar Imageries And Other Data

5th Step: Formulation Of The 5th Step: Formulation Of The ForecastForecast

Aviation Aviation meteorologymeteorology

• Aviation meteorology deals with the Aviation meteorology deals with the impact of weather on air traffic impact of weather on air traffic management. It is important for air crews management. It is important for air crews to understand the implications of weather to understand the implications of weather on their flight plan as well as their aircrafton their flight plan as well as their aircraft

Agricultural meteorologyAgricultural meteorology

involves the integration of climatological and meteorological data and techniques into agricultural problems, such as crop production, soil moisture, moisture stress, and migration of pests. A good background in basic math and sciences is required.

HydrometeorologyHydrometeorology is a branch is a branch

of meteorology and hydrology that studies of meteorology and hydrology that studies the transfer of water and energy between the transfer of water and energy between

the land surface and the the land surface and the lower atmosphere. lower atmosphere.

Nuclear meteorologyNuclear meteorology

Nuclear meteorology investigates the Nuclear meteorology investigates the distribution distribution of radioactive aerosols and gases in the of radioactive aerosols and gases in the atmosphere atmosphere

Maritime meteorologyMaritime meteorology

deals with air and wave forecasts for ships deals with air and wave forecasts for ships operating at sea. operating at sea.