Download Weather and Climate Atmosphere the place of Weather

Climate and Design
Università IUAV di Venezia, Environmental Building Physics– Introduction to sustainability
Integrated Studio 1 – Master Degree in Architecture and Innovation
The target of a “Sustainable” Design has
to be a responsible architecture:
Climate Analysis for Buildings Design 1:
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Adapted to the climate;
Climate and site analysis
Target conditions definition
Technical knowledge
Compatible with the Environment;
Energy Efficient;
ARCHITECTURE
Consuming few raw materials.
Weather and Climate
Many abilities coming from different
Fabio Peron
Università IUAV - Venezia
scientific areas are needed.
Usually not all properties of the architect.
It is a very challenging task
Università IUAV Environmental Building Physics – prof. Fabio Peron
Atmosphere the place of Weather
Weather and Climate
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Università IUAV Environmental Building Physics – prof. Fabio Peron
The earth’s
atmosphere is
composed of 4 layers
Weather describes the
state of the atmosphere at
any particular time.
• Thermosphere
Weather can be described
in terms of temperature,
• Mesosphere
precipitation (snow, rain &
hail), wind speed and
direction, visibility and
cloud amounts.
• Troposphere
• Stratosphere
The earth’s weather
takes place in the
lowest level called the
Troposphere.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Weather and Air masses
Air masses
main types of
air masses
affecting
Europe
• An air mass is a large body of air with similar temperature
and/or humidity.
• Air masses form in stable “source regions” such as in the sub
tropics or near to the poles.
Winter
Summer
Classification
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Tropical Maritime (Tm) - mild and moist
•
Tropical Continental (Tc) - warm and dry
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Polar Maritime (Pm) - cool and moist
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Polar Continental (Pc) - cold and dry
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Arctic Maritime (Am) - cold and moist
All Year
Air masses move
Air masses don’t mix
Air masses follow pressure gradient
Università IUAV Environmental Building Physics – prof. Fabio Peron
Air movements: high and low pressure
Università IUAV Environmental Building Physics – prof. Fabio Peron
Air movements: high and low pressure
Air circulation involves:
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descending flux to the ground of cold and dry air
(Subsidence); this air heat adiabatically and generates
HIGH PRESSURE ZONE (signed with H or A)
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ascenting flux of warm and humid air (Convection); this air
cold adiabatically and generates LOW PRESSURE ZONE
(signed with L or B)
Winds circulation at high and low pressure
Cyclonic convergence
Università IUAV Environmental Building Physics – prof. Fabio Peron
Anticyclonic divergence
Università IUAV Environmental Building Physics – prof. Fabio Peron
Weather and Sky cover
Clouds
What are clouds?
• Clouds are formed of tiny droplets of water or ice.
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• Clouds form when water vapour cools and condenses.
The amount of the sky
obscured by cloud
Different types of clouds
Sometimes even the
speed and direction in
which the clouds are
moving are recorded
using a nephoscope
• The temperature at which condensation occurs is called dew
point.
• Condensation also requires nucleii (small particles) such as dust.
What happens when air is cooled?
• Relative humidity increases.
• Dew point is reached (100% relative humidity).
• Water vapour (invisible) condenses to form water droplets (visible).
• Sometimes the water vapour may change straight into solid state:
called sublimation.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Clouds
Università IUAV Environmental Building Physics – prof. Fabio Peron
Cloud types: Cumulonimbus
How is air cooled?
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Contact e.g. with a cold surface
such as over land in winter.
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Convection eg uplift over warm
ground.
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Orographic eg rising over
mountains.
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Frontal eg when a mass of warm
air meets and rises over a mass
of cold air.
Fluffy clouds from low to hight level (1,000 to 6,000m)
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Cloud types: Cumulus
Cloud types: Stratus
Fluffy clouds Cumulus (Cu) ), Middle level (2,000 to 6, 000m)
Flat clouds Stratus (St), Low level (below 2000m)
Università IUAV Environmental Building Physics – prof. Fabio Peron
Cloud types: Cirrus
Università IUAV Environmental Building Physics – prof. Fabio Peron
Rainfall
Wispy clouds Cirrus (Ci), High level above 6,000m
Università IUAV Environmental Building Physics – prof. Fabio Peron
• In Italy it rains the most in the
autumn and in mountainous areas
• Rain is brought across Italy from
weather systems called front
coming from west and north.
• In summer showers result from
convection on warm days
• Rain cames from cooling of air by
one of the following mechanisms:
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Contact e.g. with a cold surface
such as over land in winter.
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Convection eg uplift over warm
ground.
•
Orographic eg rising over
mountains.
•
Frontal eg when a mass of warm
air meets and rises over a mass
of cold air.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Orographic rainfall
Cyclonic Rainfall
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Convectional rainfall
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Depressions are areas of
low pressure formed
when cold and warm air
meet
The warm air rises above
the cold air to form a
front
There are two types of
fronts depending on the
way in which the air
masses are moving.
Fair Weather
Common on hot summer
days inland
Hot air rises quickly and
condenses to form
cumulonimbus
Water freezes at the top
of the cloud forming hail
Associated with lightning
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Fair weather is produced by
high pressure
High pressure forms
anticyclones
Air sinks and prevents the
formation of rain clouds
Anticyclones cause heatwaves
in summer and frosty/foggy
mornings in winter
Forecasting the Weather
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A Satellite Image
Modern forecasts use
computers to simulate the
likely weather based on
careful observations from
100s of weather stations
round the world
Satellite images and radar
give a better picture of the
weather over a wide area
A Radar Image
The Weather Map
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Cyclonic rainfall moving
in from the west
The brighter the colour,
the heavier the rainfall
Mountains intensify the
rain such as over the
Scottish Highlands
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Weather maps summarise
the weather over a wide
area using symbols
What symbols are used for:
pressure, wind direction &
strength, cloud cover and
rainfall?
The Climate Machine
Weather and Climate
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Climate describes the
INGV - Istituto Nazionale di Geofisica e Vulcanologia - Italy
average weather of a
particular part of the
world at different times of
the year
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In Italy we would expect
hot summers and mild
winters with intense
rainfall in autumn
Solar
Radiation
Earth
Radiation
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Atmosphere
Climate and Atmosphere
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Without an atmosphere earth
radiate more energy to space
Presence of the atmosphere
limits earth radiation to space
Detailed Earth Energy Budget
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate, Sun radiation and Earth
Climate, Sun radiation and Earth
Four Astronomical factors that determine how much
radiation is received by the Earth at a given location
are the following:
Earth is a sphere: the same
power is distributed in
different areas.
• Sphericity of the Earth
• Axial Tilt
• Elliptical Orbit of The
Earth
• Daily Earth Rotation
Intensity is higher around equator.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate, Sun radiation and Earth
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Earth motion
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During the course of
the year the Earth tilts
towards and away from
the sun
• Solar intensity, defined as the energy per area, governs earth's seasonal
changes.
• A common unit for solar intensity is Watts per meter square (Wm-2). The solar
intensity hitting directly at the top of the atmosphere is about 1380 Wm-2.
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The mid-points of this
cycle are called the
equinoxes (spring and
autumn)
• A sunlight beam that strikes at an angle is spread across a greater surface area,
and is a less intense heat source than a beam impinging directly.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Earth motion
Climate and Earth motion
January
July
• Earth's tilt of 23.5° and revolution around the sun creates seasonal solar
exposure and heating patterns.
e = 0,017
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Earth motion
from Geoscience animation
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A solstice tilt keeps a polar region with either 24 hours of light or darkness.
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A equinox tilt perfectly provides 12 hours of night and 12 hours of day for all
non-polar regions.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Earth motion
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and Earth motion
Climate and Earth motion
During the summer, north of the arctic circle reveals a period of 24 hour
sunlight, where the earth's surface does not rotate out of solar
exposure, but instead experiences a midnight sun.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Seasonal variations
The apparent path of the sun across the sky as observed at different latitudes during
the solstices and equinoxes.
Summer noon time sun in the northern mid-latitudes is also higher above the horizon
than the winter sun.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Seasonal variations
Season & day length
Summer days are
warmer because the
sun is higher in the sky
and there are more
hours of daylight.
Winter days are colder
because the sun is
lower in the sky and
there are less hours of
daylight.
Earth's surface is 5 million kilometers further from the sun in summer than
in winter, indicating that seasonal warmth is controlled by more than solar
proximity.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Units are in Langleys per day (1 Langley=1 cal/cm2)
Università IUAV Environmental Building Physics – prof. Fabio Peron
Seasonal variations
Seasonal variations
March 20th
Vernal Equinox
June 21st
Summer Solstice
Sept 22nd
Autumnal Equinox
Dec 21st
Winter Solstice
Winter mean temperatures around
the world
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Solar radiation and latitude
Seasonal variations
summer mean temperatures around
the world
Università IUAV Environmental Building Physics – prof. Fabio Peron
Equatorial and tropical belt have a surplus of energy,
temperate and polar areas have a deficit.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Energy redistribution: Global Circulation
Energy Redistribution: Oceanic Streams
Oceanic streams
and
prevailing winds
redistribute
energy on
Earth surface.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climate and climatic parameters
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climatic guide indicators
The climate in a site is defined by the long-term behaviours (20-30
years) of the atmospheric physical conditions.
Climate is pointed out by the statistical analisys of the measured
atmospheric parameters:
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Solar radiation
Air temperature
Air humidity
Velocity and direction of wind
Rain precipitations
Clouds and sky covering
Climatic analisys refer to yearly mean temperature, mean temperature
of hottest and coldest month, yearly thermal excurtion, mean rain
precipitations.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Koppen Climatic classification
Koppen Climatic classification
KOPPEN CLASSIFICATION
A
[HUMID
WARM]
Mean temperature in coldest month above 18 °C, absence of winter, little
yearly thermal range and little daily thermal range
B
[DRY
WARM]
Evaporation overcames the precipitation
C
[MILD]
Mean temperature in coldest month under 18°C but is above 3°C;
variable precipitations and variable weather.
D
[COLD]
Mean temperature in coldest month under -3 °C and for the warmest month
above 10 °C; winter is long with snow on the ground; summer is short and
warm; wide thermal range, usually above 40° C.
E
[POLAR]
Mean temperature in warmest month under 10 °C; absence of summer;
Humid warm, Dry warm, Mild , Microthermal, Polar
Università IUAV Environmental Building Physics – prof. Fabio Peron
Italian Climates
Italian Climates
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Università IUAV Environmental Building Physics – prof. Fabio Peron
Alps: high mountain climate with
humid summer
Apennines: humid cool temperate
suboceanic
Po basin and Adriatic coastline:
northern temperate subcontinental
Ligurian and Tyrrhenian coast:
temperate with warm wet winter
and dry summer
Adriatic coast in the south and the
Ionian: warm temperate locally arid
with long wet winter and dry
summer
Sicily and Sardinia: from temperate
warm with dry summer to arid with
long dry summer .
Yearly mean temperature
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Italian Climates
Global warming
Yearly mean
precipitations
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Italian Climates
Global warming and
precipitations
Mature bananas in Bologna
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Italian Climates
Italian Climates
Level of ice on the Adamello Glacier in the Alps is lower and lower: the limit for wood is
moving upward, the cold season is shorter.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Global warming a topic of the times
Ottimisti
ma preoccupati
Università IUAV Environmental Building Physics – prof. Fabio Peron
Credits
M. J. Lewis – Pitsford Hall Weather Station
L. Lombroso – Università Modena e Reggio
A. Navarra - INGV
Università IUAV Environmental Building Physics – prof. Fabio Peron