2. Theme 2 - Weather and Climate
Weather
Is the conditions of the atmosphere in
the short term - over a day or a week.
It is made up of temperature, rainfall,
humidity, wind speed, wind direction,
air pressure and other characteristics of
the air around us.
Climate
Is the generalised conditions of the
precipitation and temperature over a
year. The figures are averaged out
over a long period of time - this is
normally a minimum of 30 years.
Weather is …
It includes …
It involves changes in the …
Climate is …
It includes …
It involves changes in the …

3. Condition High or Low Pressure
Cold and warm fronts
Sinking air
High level of
condensation
Low precipitation
Sunny conditions in
summer
Cold and frosty
conditions in winter
Condition High or Low Pressure
Warm air rising over
cold air
Thunderstorms in the
afternoon in Summer.
Very stable conditions
for a number of days
or weeks
Low levels of
condensation.
Rain, followed by few
hours of dry, followed
by heavy rain.
Storm conditions and
isobars that are close
together.
High or Low Pressure?
High
High
Low
High
High
Low
High
High
High
Low
Low
Low

4. Pm
Pc
TcTm
Am

5. The Importance of Air Masses
An air mass is a block of air that has similar temperature and moisture
characteristics. Where the ‘air comes from’ has a big impact on our weather
and climate.

7. The Importance of Air Masses
An air mass is a block of air that has similar temperature and moisture
characteristics. Where the ‘air comes from’ has a big impact on our weather
and climate.

8. Link - 1’10” in
Link 2 Link 3

15. Sandstorms in the Sahara Desert in Northern Africa
collect and transport lots of sand and dust into the
atmosphere. This is picked up by the wind moving
clockwise in the high pressure.
Air in a high
pressure
(anticyclone)
moves in a
clockwise
direction. This
creates an air
mass moving over
the UK from the
South.
The Tropical
Continental Air Mass
(Tc) is full of dust and
sand which have
been picked up from
the storms in the
Sahara
Air in a high
pressure sinks
creating very
stable conditions.
Wind speeds tend
to be light and
calm.
Sinking air with calm conditions
means that levels of pollution in
the atmosphere can build up. The
air mass affecting the UK crosses
some of the big industrial regions
of Europe - Northern France,
Belgium and Germany.
High Pressure
Stretch and Challenge
•High pressure systems block other
weather systems, especially low
pressures and so can last for
several days, even weeks. This
means the weather conditions can
remain similar for some time.
•Isobars in High Pressure systems
tend to be spread out; the
pressure gradient is low.
•Sinking air means the chance of
condensation is low, and thus
precipitation levels are low. This
means there is little or no rainfall
to wash pollutants and dust out of
the atmosphere.
•Microclimates in urban areas
mean that high pressure
conditions trap pollution emitted
by transport and industrial sources
in the local area. This combines
with pollutants transported from
further afield.

17. • Moves from East to West
• Crosses three countries -
Philippines 26-27 September,
Vietnam 29th September, and
Laos/Cambodia on 30th
September.
• Turns from a tropical depression,
into a Tropical Storm, into Typhoon
and then back into a Tropical
Storm.
• Begins in the Philippine Sea, and
moves west across the South China
Sea.
• North of the Equator but South of
the Tropic of Cancer.

18. • Highest number of deaths in the
Philippines.
• Whereas lowest number of deaths
in Cambodia.
• Deaths in Vietnam and Cambodia
together are less than those in the
Philippines.
• Damage is greatest in Vietnam.
• Damage is lowest in Philippines.
• Damage in the Philippines and
Cambodia together is less than
that in Vietnam.
• Homelessness is highest in
Philippines.
• In contrast Cambodia has the
lowest homelessness.
• Similarly Vietnam had a high level
of evacuation - although this isn’t
the same as homelessness.

19. Cause of floods:
• Impermeable surfaces - lack of
infiltration, so rapid run-off.
• Poor drainage in informal
settlements - rapid population
growth led to poor level of
infrastructure.
• High population density - lots of
people affected in a small area.
Impact on Quality life
• Economic:
• Social:
• Environmental:
People can’t get to work easily. Many
businesses shut. People will see a fall
in income which could increase poverty
when people are already ‘on the edge’.
Emergency services cannot access those
who need help - rise in diseases and ill
health. Communities are cut off - people
cannot access food and clean water.
Sanitation systems are flooded - dirty and contaminated
water in many areas. Spreads disease very easily - young
people, the sick and the old very vulnerable.

20. You’ve been given some case study revision notes about the
impact of low pressure weather systems. However, they need
improving - your challenge is to mark them and indicate where
improvements need to be made, and to make them.
Check for:
• Detailed information.
• Specific evidence and facts.
• Clear structure and small chunks of information.
• Complex ideas and understanding - stretch yourself and apply ‘BIG’
ideas.

21. For a period of weather caused by high or low pressure.
• Name and locate the area affected by the weather.
• Describe the main features of the weather.
• Explain how the weather affected different groups of people.
[8 marks]
Name:
• UK - high levels of rain and flooding in 2012.
Describe:
• Higher than average rainfall
• Caused by higher air temperatures linked to Global Warming
• Caused by change in the position of the Jet Stream - air masses created
conditions for high rainfall
• Ground became quickly saturated - flooding in many drainage basins across the
UK
• Higher populations on flood plains - more people at risk of flooding
Explain impacts on different groups:
• Homeowners
• Farmers
• Insurance Companies
• People in General

22. Challenge
What does warm air rise?
Your answer?

28. Describe
Explain
10
o
C, 8 oktas of cloud,
drizzle, Force 5 Wind from
the SSW.
Located at the warm front.
In the next few hours it will
get warmer and the drizzle
will stop.
Warm air is rising over cold
air. As the air rises it
cools, and this means
water vapour condenses to
form clouds. This causes
the rainfall, along with the
TM air that is warm and
moist which comes from
the SSW.

29. Describe
Explain
11
o
C, 8 oktas of cloud,
rain, Force 5 Wind from the
W.
Located at the warm front.
In the next few hours it will
briefly get warmer and then
it will rain heavily as the
cold front arrives.
Warm air is rising over cold
air. As the air rises it
cools, and this means
water vapour condenses to
form clouds. This causes
the rainfall, along with the
TM air that is warm and
moist which comes from
the W.

30. Describe
Explain
13
o
C, 3 oktas of cloud,
rain, Force 3 Wind from the
SW.
Located in the warm
sector. In the next few
hours it will begin to rain
heavily as the cold front
arrives and temperatures
will fall.
In between the warm and
cold fronts is a block of
warm air. This creates an
area of more stable and
calmer weather. However
as the cold front
approaches, warm air will
once again rise over cold
creating the conditions for
rainfall.

31. The weather at Point A is wet and
windy. Temperatures are 9oC,
and the wind is blowing from the
South West, and is Force 4.
There is quite a lots of cloud, and
there is drizzle.
This is the warm front where a
warm air mass is meeting a cold
air mass. They don’t mix because
they are different densities.
Condensation leads to
precipitation and this is why it is
raining.
The weather at Point A is wet and
windy. Temperatures are 9oC,
and the wind is blowing from the
South West, and is Force 4.
There are 7 okras of cloud cover
and it is drizzling.
This is the warm front. Warm air
is being forced over cold air
because it is less dense. As it
rises it cools, which lets water
vapour condense to form clouds.
As the clouds build up eventually
it will rain. This frontal system is a
low pressure as the different air
masses have different densities
and one rises over the other.
Answer A Answer B