THE EARTH’S THE EARTH’S ATMOSPHEREATMOSPHERE

► The Atmosphere is a mixture of gasses that sorrounds The Atmosphere is a mixture of gasses that sorrounds the Earth and protects us by blocking out dangerous the Earth and protects us by blocking out dangerous rays from the Sun. It is around 800 Km thick.rays from the Sun. It is around 800 Km thick.

► Is made up of gasses in different proportions:Is made up of gasses in different proportions:

78% nitrogen.78% nitrogen. 21% oxygen.21% oxygen. 1% other gasses: argon, carbon dioxide, water 1% other gasses: argon, carbon dioxide, water

vapour, ozone, etc.vapour, ozone, etc.

THE LAYERS OF THE ATMOSPHERETHE LAYERS OF THE ATMOSPHERE

► There are four layers:There are four layers:

TroposphereTroposphere StratosphereStratosphere MesosphereMesosphere ThermosphereThermosphere

► Troposphere:Troposphere:

It is 15 Km thick.It is 15 Km thick. It contains 80% of the total mass of the atmosphere.It contains 80% of the total mass of the atmosphere. Here is where the meteorological phenomena occur.Here is where the meteorological phenomena occur. It gets colder with height.It gets colder with height. Its upper limit is called Tropopause.Its upper limit is called Tropopause.

► Stratosphere:Stratosphere:

It is about 30 Km thick.It is about 30 Km thick. Its temperature increases with height.Its temperature increases with height. The ozone layer is here.The ozone layer is here. Its upper limit is called stratopause.Its upper limit is called stratopause.

► Mesosphere:Mesosphere:

It is about 40 Km thick.It is about 40 Km thick. It contains clouds of ice and dust.It contains clouds of ice and dust. It gets colder with heigth.It gets colder with heigth. Its upper limit is called mesopause.Its upper limit is called mesopause.

► Thermosphere:Thermosphere:

The highest and the thickest layer.The highest and the thickest layer. Its temperature increases to 1.000 ºC due to the X-Its temperature increases to 1.000 ºC due to the X-

rays and the gamma rays from the Sun.rays and the gamma rays from the Sun.

THE WEATHERTHE WEATHER

WHAT MAKES UP THE WHAT MAKES UP THE WEATHER?WEATHER?

► The The weatherweather describes the state of atmospheric describes the state of atmospheric conditions at a certain place, over a short period of time.conditions at a certain place, over a short period of time.

► Weather is made up of different things:Weather is made up of different things:

► Wind: movements of air.Wind: movements of air.► Temperature: how hot or cold the air is.Temperature: how hot or cold the air is.► Precipitations: water that falls to the ground: Precipitations: water that falls to the ground:

rain, snow and hail.rain, snow and hail.► Humidity: the concentration of water vapour in Humidity: the concentration of water vapour in

the atmosphere.the atmosphere.► Clouds: formed when air gets cold and Clouds: formed when air gets cold and

condensates. condensates.

THE ATMOSPHERIC PRESSURETHE ATMOSPHERIC PRESSURE

► Air has weight. Air has weight. ► The pressure it exerts on a surface is called Atmospheric The pressure it exerts on a surface is called Atmospheric

Pressure.Pressure.

► Where is the pressure Where is the pressure going to be highest?going to be highest?

► And lowest?And lowest?

PREDICTING THE PREDICTING THE WEATHERWEATHER

LOW PRESSURE AREASLOW PRESSURE AREAS

They are areas where air rises. So, there is no much air They are areas where air rises. So, there is no much air on the terrestrial surface, and the pressure it exerts is on the terrestrial surface, and the pressure it exerts is low.low.

► As the air rises, it gets colder, As the air rises, it gets colder, condenses, and form clouds.condenses, and form clouds.► These clouds will produce These clouds will produce precipitations (bad weather).precipitations (bad weather).► These areas are also called These areas are also called SquallsSqualls ..

HIGH PRESSURE AREASHIGH PRESSURE AREAS

They are areas where air descends. So, there is a lot of air They are areas where air descends. So, there is a lot of air on the terrestrial surface, and the pressure it exerts is high.on the terrestrial surface, and the pressure it exerts is high.

► As the air descends, As the air descends, it gets hot and dry, does not condense, it gets hot and dry, does not condense, and does not form clouds.and does not form clouds.► So, in these areas we will findSo, in these areas we will findgood weather.good weather.► These areas are also calledThese areas are also called Anticyclons.Anticyclons.

CLIMATECLIMATE

► ClimateClimate describes the weather in an area over a long describes the weather in an area over a long period of time.period of time.

► These factors affect climate:These factors affect climate:

LatitudeLatitude : how far north or south a place is from the : how far north or south a place is from the Equator. The Sun heats the most at the Equator, and Equator. The Sun heats the most at the Equator, and the least at the Poles. the least at the Poles.

Alt itudeAlt itude : the height above the sea level. The higher : the height above the sea level. The higher a place is, the colder it will be.a place is, the colder it will be.

► Distance from the sea:Distance from the sea:

In winter the sea releases heat, keeping coastal areas In winter the sea releases heat, keeping coastal areas warmer.warmer.

In summer, cold sea keeps coastal areas cooler.In summer, cold sea keeps coastal areas cooler.

So, temperatures are milder in coastal areas than in So, temperatures are milder in coastal areas than in inland areas.inland areas.

CLOUDS AND CLOUDS AND PRECIPITATIONPRECIPITATION

► CloudsClouds are formed when rising air cools and condenses are formed when rising air cools and condenses to form liquid drops.to form liquid drops.

► RainRain occurs when condensation makes large and heavy occurs when condensation makes large and heavy droplets which fall to Earth.droplets which fall to Earth.

► SnowSnow and and HailHail occur when the water vapour in the air occur when the water vapour in the air freezes.freezes.

► There are different types of clouds:There are different types of clouds:

- FOGFOG : a cloud in contact with the ground.: a cloud in contact with the ground.

- CUMULUSCUMULUS : white and puffy clouds that usually : white and puffy clouds that usually mean good weather.mean good weather.

CIRRUSCIRRUS : thin and high clouds made of ice crystals.: thin and high clouds made of ice crystals.

CLIMATE DIAGRAMSCLIMATE DIAGRAMS

► Climate diagrams summarize temperature and precipitation Climate diagrams summarize temperature and precipitation information for a given area.information for a given area.

► For one year, we represent each month on the horizontal For one year, we represent each month on the horizontal axis.axis.

► Temperature and precipitation are represented on the Temperature and precipitation are represented on the vertical axisvertical axis

METEOROLOGICAL INSTRUMENTSMETEOROLOGICAL INSTRUMENTS

► Using your book, look for the correct instrument to Using your book, look for the correct instrument to measure these phenomena:measure these phenomena:

The wind directionThe wind direction The amount of rainfallThe amount of rainfall The temperatureThe temperature The wind speedThe wind speed The humidityThe humidity The atmospheric pressureThe atmospheric pressure