Transcript   Weather: The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity and direction, barometric.

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Weather: The state of the
atmosphere at a given time
and place, with respect to
variables such as temperature,
moisture, wind velocity and
direction, barometric pressure,
cloud cover
Climate: The meteorological
conditions, including
temperature, precipitation,
and wind, that characteristically
prevail in a particular region
over extended periods of time.
Solar Energy affects weather and climate patterns
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Earth must be in
equilibrium: not
growing
significantly
warmer or cooler
Heat is transferred
from surplus to
deficit: equator to
poles
Albedo Effect
How is heat transferred??
Through Air and Water Circulation
Easterlies
(from the east)
Westerlies
(from the west)
60°N
Northeast
tradewinds
30°N
(Doldrums)
equator
30°S
60°S
Initial pattern of
air circulation
Fig. 6.6b, p. 125
Southeast
tradewinds
Westerlies
Easterlies
Deflections in the
paths of air flow
near the earth’s surface
Animation
Fig. 6.8, p. 126
Pressure Gradients
What is wind and why does it
occur?
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A horizontal
movement of
air
Vertical
movements
are currents
or updrafts
and
downdrafts
Isobars: Predict Direction and Intensity of Wind
Top View
The Coriolis effect deflects winds and
ocean currents:
To the right in the northern hemisphere
To the left in the southern hemisphere
(animation)
Friction slows surface wind speed and
weakens the Coriolis effect
Global Wind Patterns
Cold, dry
air falls
Polar cap
Polar
Cell
air rises
— rain
Moist Moist
air rises
— rain
Arctic tundra
Evergreen
60° coniferous forest
Temperate deciduous
forest and grassland
Desert
30°
Tropical deciduous
forest
0°
Equator
Ferrell
Cell
Cool, dry
air falls
Hadley
Cell
Moist
air rises,
cools, and
releases
moisture
as rain
Tropical
rain forest
Tropical deciduous forest
30°
Hadley
Cell
Desert
Temperate deciduous
forest and grassland
Cool, dry
air falls
60°
Ferrell
Cell
Polar cap
Cold,
dry air
falls
Polar
Cell
Moist air rises — rain
ENSO = El Nino Southern
Oscillation
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Normal trade winds blow from east to west and
cause upwellings, nutrient rich bottom water is
pushed to surface.
ENSO reverses the direction of the trade winds (now
from W
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E) which depresses upwellings.
Occurs every 3-7 yrs and can last from 8-14 months.
(Can seriously disrupt ecosystems if lasting longer than a year!)
*La Nina (2011-2012 NOAA advisory)
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Thermocline – zone of gradual temperature change
separating warm and cold water. Animation
Fronts
- the boundary between two air
masses with different
temperatures and densities.
 Dramatic changes in weather
occur along a front
Warm Front
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The boundary between
an advancing warm air
masses and the cooler
one its replacing
• produces many layers
of clouds at different
altitudes
• leads to rainfall and
days of cloudy skies
Warm air = always
rises, less dense than
cold air
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The leading edge
of an advancing
mass of cold air
• produces
thunderheads
• leads to high
surface winds
and T-storms
• cooler
temperatures
and clear skies
Cold Front
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Violent storms
called tornadoes
(form over land) and
tropical cyclones
(form over warm
ocean waters)
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Tropical cyclones
are hurricanes in
the Atlantic and
typhoons in the
Pacific Ocean
Changes in barometric
pressure with storms
Weather Extremes
Tornados
Devices
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Meteorologists use
devices such as weather
balloons, aircraft, ships,
radar, and satellites to
obtain data on variables
such as atmospheric
pressure, precipitation,
temperature, wind
speeds, and locations of
air masses and fronts
• data is used to create
weather maps
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Average long term
weather of an area
• Seasonal
variations and
weather extremes
averaged over a
long period (at least
30 years)
• 2 Main factors
 temperature
 amount and
distribution of
precipitation
Climate
Climate
5 Major factors that
influence climate:
is
the average weather patterns for an area
Over a long period of time
(30 - 1,000,000 years).
It is determined by
1) Average Temperature –
Polar, Temperate, tropical
2) Average Precipitation – dry
to very wet; determines
small vegetation to large
trees
3) Uneven heating of the
Earth’s surface – latitude/
altitude cause pressure
gradients
4) Seasons – Earth’s rotation
5) Properties of water and air –
pressure, heating abilities
Average Precipitation
and
Average Temperature
which are influenced by
latitude
altitude
ocean currents
and affects
where people live
how people live
what they
grow and eat
WORLD CLIMATES
WORLD ECOSYSTEMS
LARGE CORRELATION
Seasonal
Changes
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Occur because the
earth’s axis is tilted. This
creates opposite seasons
in the northern and
southern hemisphere
• which is a factor that
determines global air
circulation patterns
• Animation
adjust latitude
for location; Pembroke Pines,
• ~26o N
Seasons
Spring
(sun aims directly
at equator)
Winter
(northern hemisphere
tilts away from sun)
23.5°
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Fall
(sun aims directly at equator)
Fig. 6.5, p. 124