HMCS Max Bernays Pre-Deployment Brief (May 2024).pptx
Microclimates
1. Microclimates
Microclimates
Valley Climates
Slope Aspect.
Anabatic and Katabatic Winds.
Land and Sea Breezes
Influence of Local Climates on
human activities.
City Climates
Reasons for differences
between rural and urban climates.
Urban heat Islands.
Pollution Dome.
Strategies to reduce the heat
island effect
4. N Facing slopes (in the SH) are warmer
w
S
N facing slopes in the SH
are warmer since theN facing
sun’s rays strike them
directly.
slope
E
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N
9. Mountain Winds – can you correctly order these statements?
Move the text boxes around and insert the arrows.
Similar circumstances
can lead to frost
and fog hollows in hilly
regions.
As the cold air
accumulates in the
valley, fog or frost
may form.
Under humid
conditions, clouds
may form over
the valley sides
On cold still nights, upper
mountain surfaces rapidly
lose heat. The air becomes
chilled and more dense and
flows down the valley sides
as a katabatic wind.
On a hot still days, air over
a heated valley floor will
expand and rise causing
anabatic draughts to move
up the valley side.
Anabatic and Katabatic
winds are also more
pronounced under
anticyclonic conditions in
mountainous areas.
10. Mountain Winds Answer
Anabatic and Katabatic
winds are also more
pronounced under
anticyclonic conditions in
mountainous areas.
On a hot still days, air over
a heated valley floor will
expand and rise causing
anabatic draughts to move
up the valley side.
Under humid
conditions, clouds
may form over
the valley sides
On cold still nights, upper
mountain surfaces rapidly
lose heat. The air becomes
chilled and more dense and
flows down the valley sides
as a katabatic wind.
Similar circumstances
can lead to frost
and fog hollows in hilly
regions .
As the cold air
accumulates in the
valley, fog or frost
may form.
12. Anabatic and Katabatic Winds
Explain what causes the
above wind to blow:
Explain what causes the
above wind to blow:
13. Anabatic Winds
An anabatic wind is a wind which blows up a steep slope or mountain-side during the day, driven
by sunshine heating the slope. A hill or mountain-top is warmed by the sun, which in turn heats
the air just above it. This air becomes relatively warmer and lighter than other air at a similar
altitude over an adjacent valley which does not get warmed as much because of the greater
distance to the ground below it and / or if it is in shade. This warmer, lighter air will rise through
convection, creating a lower-pressure region into which the higher-pressure air at the bottom of
the slope gets drawn, causing the wind.
14. Katabatic Winds
Opposite of Anabatic Wind, downslope movement as air cools.
Can form fog or mist at bottom of slope in valley
15. Convection currents
Local weather is affected by the movement of air masses all
over the world.
Some of this movement happens because the Sun heats
the surface of the Earth unevenly. Temperature differences
in the air cause convection currents.
Convection currents in the
atmosphere move warm air
into colder areas. These
wind currents take place
anywhere there are
temperature differences in
the air. This often happens in
places with nearby water.
18. Sea and Land breezes
There are daily
changes in wind
direction due to
unequal heating
and cooling of land
versus water.
Warm air during
day over land rises
and cool air from
sea moves onshore
(with or without
water vapor)
causing a Sea
Breeze.
Sea Breeze
LP
HP
Land Breeze
LP
HP
21. Local winds can act together to form strong winds
Spot the error!
22. Microclimates
URBAN CLIMATES
• Reasons for differences between
rural and urban climates.
• Urban Heat Islands.
• Pollution Dome.
• Strategies to reduce the Heat
Island effect.
28. Complete the following. Go into editing mode:
Factors that cause the Urban Heat Island effect:
Artificial Material:
Artificial Heat production:
Urban Morphology:
Spatial Growth:
Dust and pollution particles:
Dust and other particles serve as:
More fog and pollution:
30. Pollution Dome
INSOLATION
During day –
land heated
WARM AIR
POLLUTED
AIR
TRAPPED
Air close to
surface- cooler
Adiabatic warming occurs with
descending stable air in
Radiation faster if
anticyclones.
no clouds
This compression can lead to a
temperature inversion at 1 or 2
In night
km above ground.
surface
This happens because on clear
cools off
nights the ground cools more
quickly and rising air warms
If there is sufficient water
vapour, relative humidity can
increase to 100%
Clouds and fog can then form
which often stays into the next
Cold air
morning.
decends
In cities this layer can trap pollutant
particles and lead to health
threatening fog (smog; smoke
and fog)
31. EXAMINATION QUESTION
1
2
3
4
What is a heat island?
Which part of the city is experiencing the highest temperature?
How have peoples lives been changed by heat islands.
Whet can be done to reduce high temperatures in cities?
