Contents

• The Weather Forecast.

• What is Weather?

• How do we Measure Weather?

• What Affects Britain’s Weather and Climate?

• Global Temperatures.

• Climate Graphs.

The Weather Forecast!

• Most people watch the weather forecast everyday – but do we really know how they gather all the information?!

What is weather?

• Weather is:

What is climate?

• Climate is:

Scotland!

How do we measure weather?

Temperature

• Air temperature is measured using maximum - minumium thermometers.

• Each temperature is read from the bottom of the marker.

• Q: What would the temperatures be on this thermometer?

A: Minimum = 9°C, Maximum = 22°C

Temperature.

• Thermometers are housed in a Stevenson Screen. These are always off the ground and painted white!

Q: Why are thermometers kept there? Why is it white?

A: It provides shelter from wind, rain, snow and animals. The white colour reflects the sunlight so heat doesn’t build up inside the box.

Precipitation. • Precipitation is any

moisture that comes from the atmosphere (rain, snow, hail).

• The amount of precipitation is measured using a rain gauge.

Q: Where do you think would be best to place a rain gauge? Beside a building or in an open space?

Sunshine hours.

• The total amount of sunshine in a day is measured using a sunshine recorder.

• The sun’s rays travel through the glass ball and burn marks onto the card behind it.

Strip of card

Sunshine

Glass Ball

Air Pressure.

• Air pressure is measured using a barometer and recorded using a barograph.

• It is measured in millibars (mb).

• Average air pressure is 1000 mb

Barometer

Wind.Wind is measured in two ways with two instruments:

1. Wind Direction – Wind Vane2. Wind Speed – Anemometer

Wind Vane: the arrow points in the direction that the wind is coming from.

Anemometer: the stronger the wind the faster the caps turn. The number of turns in a given time gives us the wind speed in knots.

Cloud cover.

• Cloud cover is measured just by using our eyes.

• You look at the sky and decide how cloudy it is – and estimate how many eigths of the sky are covered.

• Cloud cover is measured in oktas.

• You also get different types of clouds.

What affects Britain’s Weather & Climate?

• The British Weather and Climate has lots of different factors which affect it.

• So why exactly do we get so much rain?

Where is Britain found?• Britain lies

between 50 and 60 degrees North.

• These are cool, temperate latitudes.

• The British climate is referred to as a Cool Temperate Maritime Climate.

• The Gulf stream also plays an important role in the British climate.

The Gulf Stream• The Gulf Stream

distributes heat from the equator north towards Northern Europe – and importantly the UK.

• This helps to give Britain its mild climate.

Global temperatures

What do you notice about all the places along the dotted line?

The further in land you go the hotter it gets in the Summer and the colder it gets in the Winter!

Showing differences in temperature.

• Temperatures are shown using isotherms.

• These lines join up places with the same temperature. Once all the places of similar

temperatures are joined together and shaded in a map like this is created!

What else affects the British weather?

• High, mountainous areas interrupt the flow of warm, moist air from the sea.

• This air is forced upwards and so cools and condenses to form rain clouds. This is known as Relief Rainfall.

Q: Where do you think the most rainfall will occur. The east coast or the west coast? Why?

Relief rainfall

High land forces the air upwards where it cools and the water vapour condenses forming clouds.

This in turn causes rain!

Warm, moist air blows in from the Atlantic

Relief rainfall

High land forces the air upwards where it cools and the water vapour condenses forming clouds.

This in turn causes rain!

Warm, moist air blows in from the Atlantic

Convectional rainfall

1. The sun heats the ground.

2. The hot ground heats the lowest air and the water from the ground is evaporated.

3. Water vapor rapidly rises, cools

and condenses.

Frontal rainfall

Warm, moist air is forced up over the denser cool air.

Water vapor condenses forming clouds and bringing rain.

Why are some areas hotter than others?

• Polar areas are cold because the suns rays hit the earth at a slant so the sun’s energy is less concentrated.

• Tropical areas are hot because the suns rays hit the earth at right angles near the equator – so the sun’s energy is concentrated.

Sun’s energy

Why do we get seasons?

S

NN

N

S

N

S

S

SUN

DECEMBERThe Sun is overhead at the Tropic of Capricorn, 23½ºS

JULYThe Sun is overhead at the Tropic of Cancer, 23½ºN

MARCHThe Sun is overhead at the Equator.

SEPTEMBERThe Sun is overhead at the Equator.

Climate Graphs.

• Climate graphs show two different things – average monthly rainfall & average monthly temperatures.

• How do you draw a climate graph?

Drawing a climate graph.

Months

Tem

per

atu

re

(°C

)

Rai

nfa

ll (m

m)

A bar-chart is drawn to show the average monthly

rainfall.

A line graph is then added to show average monthly

temperatures.

Draw a climate graph!The person nearest the window is to draw the climate graph for Inverness – the person nearest the door is to draw the

climate graph for Stornoway!

TV symbol meanings

Synoptic chart symbols

Mist

Fog Thunder

Drizzle

Rain Snow

Hail Shower

Heavyrain

Heavysnow

Air Masses

• An air mass is a large ‘parcel’ of air that has certain characteristics, depending on where they originally came from.

What air masses affect Britain?

• Britain is affected by five air masses :

– Polar Maritime (mP)– Tropical Maritime (mT)– Polar Continental (cP)– Arctic Maritime (mA)– Tropical Continental (cT)

• Each of the air masses brings a different type of weather, because each one originally formed over the land or sea, in a warm or cold part of the world.

Enquiry Skills

• In the exam you could be asked how you would either gather or process weather data.

• How would you gather information on :

Processing Techniques

• The tables on the next slide show climate data for Glasgow and Stornoway airports.

• Choose a processing technique for each of the weather elements and explain how you would use these techniques to compare the data from the two airports.

• “The technique I would use is…”• “I chose this technique because…”

Weather Data