Download Weather and Climate

Weather and Climate
Climate vs. Weather
• Weather: Short term state of the atmosphere.
– Temperature, humidity, cloud cover, precipitation,
winds, visibility, air pressure, air pollution, etc…
• Climate: The average weather conditions in an
area over a long period of time
– Described by temperature and precipitation
Measurement
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Temperature
Air Pressure
Definition
Instrument
Thermometer
How hot or cold the air is
The weight of the air
Barometer
Wind Speed
How fast the wind is blowing
Anemometer
Wind Direction
Where the wind is blowing from
Weather Vane
Humidity
Amount of water vapor in the air
Amount of rain or snow that falls
Precipitation
Hygrometer
Rain Gauge
Measuring Weather
Instruments used in measuring weather in the upper atmosphere
•
Radiosonde:
•
Radar: radio detection and ranging
•
Weather Satellites:
•
Computers
– a package of instruments that is carried aloft by balloons to measure upper atmospheric
conditions, including temperature, dew point, and wind velocity
– sends measurements as radio waves to a receiver that records the information.
– When the balloon reaches a very high altitude, the balloon expands and bursts, and the
radiosonde parachutes back to Earth.
– a system that uses reflected radio waves to determine the velocity and location of objects
– The newest Doppler radar can indicate the precise location, movement, and extent of a storm.
It can also indicate the intensity of precipitation and wind patterns within a storm.
– Satellite images provide weather information for regions where observations cannot be made
from ground.
– The direction and speed of the wind at the level of the clouds can also be measured by
examining a continuous sequence of cloud images.
– Satellite instruments can also measure marine conditions.
– Solving very difficult mathematical equations
– Store weather data
– Can provide information that is useful in forecasting weather changes
Measuring Weather Continue
Measuring Climate
Methods of Studying Past Climates
Method
What is measured
What is indicated
Length of time
measured
Ice Core
Concentrations of
gases in ice and
melt water
High levels of CO2 indicate
warmer climate; ice ages follow
decreases in CO2
Hundreds of
thousand of
years
Sea-floor
Sediment
Concentration of
18O in shells of
microorganisms
High 18O levels indicate cool
water; lower 18O levels indicate
warm water.
Hundreds of
thousand of
years
Fossils
Pollen types, leaf
shapes, and animal
body adaptations
Flower pollens and broad leaves
indicate warm climates;
evergreen pollens and small,
waxy leaves indicate cool
climates. Animal fossils show
adaptations to climate changes.
Millions of years
Thin rings indicate cool weather
and less precipitation
Hundreds to
thousands of
years
Tree Rings Ring width
Measuring Climate Continue
• Long term weather measurements
– Satellites
• Geological Evidence
– Evidence of glaciation
– Rock layers
Climate Graph
Creation of Wind that eventually
leads to weather and climate.
Flashlight Mini Lab
• Flashlight Demo:
– Predictions: Which will have the most energy per given
area, the 90 degree or the 30 degree angle flashlight?
– Hold the flashlight at 90 degree angle and about 10 inches
above your paper
• Draw an outline around the beam
• Count the number of squares:
– Hold the flashlight at 30 degree angle and about 10 inches
above your paper
• Draw an outline around the beam
• Count the number of squares:
• Which has the most energy per given area?
– 90 degree
Direct vs. Indirect Sunlight
• Sun gives off the same amount of radiation
and stays the same temperature!
• The tilt of the Earth (23 ½ degrees)
determines the concentration of the sun in a
given area
– Small area = large concentration
– Big area = less concentration
http://www.sci.uidaho.edu/scripter/geog100/lect/02-energy-seasonsatmosphere/02-pt-1-solar-energy.htm
HOW DIRECT AND INDIRECT RELATES
TO CLIMATES
Winter in Northern Hemisphere
• Tilted away from the Sun
• Cooler Temperatures = Cooler
Climates
• Higher latitudes
• Sun’s rays hit Earth at a smaller
angle
• Solar energy is spread out over a
larger area
windows2universe.org
Summer in Northern Hemisphere
• Tilted towards the Sun
• Higher Temperatures = Warmer
Climates
• Lower latitudes
• Sun’s rays hit Earth around 90
degrees
• Solar energy is more direct,
smaller areas
windows2universe.org
HOW DIRECT AND INDIRECT RELATE
TO WIND
Uneven Heating of the Earth
• Is warm air more or less dense the cold air?
– Less Dense
• If you have cold air at the poles and warm air at the
equator where do you think each air mass will want to
move and why?
– Cold air mass will move toward the warm air mass and the
warm air mass will move toward the cold air mass because
of convection.
• Convection: the movement of matter due to differences in the
density that are caused by temperature variations; can result in
the transfer of energy as heat.
– Convection currents/Density currents
• The convection of air is a key piece in creating wind.
Atmospheric Pressure(Air Pressure)
• atmospheric pressure: the force per unit area
that is exerted on a surface by the weight of
the atmosphere
– decreases as altitude increases
– changes as a result of differences in temperature
and in the amount of water vapor in the air
Atmospheric Pressure Continue
Atmospheric Pressure Continue
Pressure Gradient
• Uneven heating of the Earth’s surface creates
pressure gradients.
• Cause air to move form high pressure areas to
low pressure areas creating wind
• http://www4.uwsp.edu/geo/faculty/ritter/ani
mation/atmosphere/pressure_gradient.gif
THE WIND’S PATH
Question
• Why doesn’t the wind blow straight to the
North and South pole from the equator?
– Rotation of the Earth, which we call the Coriolis
Effect
Coriolis Effect
• Coriolis effect: the curving of the path of a moving object
from an otherwise straight path due to Earth’s rotation
• Circulation of atmosphere and ocean currents are effected.
• http://www.youtube.com/watch?v=aeY9tY9vKgs&feature=r
elated
• Hold the spherical device in your hand and rotate it
counterclockwise (West to East) and look at it from the top.
Which way is it rotating?
– counterclockwise
• Now keep rotating it counterclockwise (West to East) and
look from the bottom, which why is it rotating?
– Clockwise
Coriolis Effect Continue
High and Low Pressure Wind
Directions
• High pressure winds
move outwards
• Low pressure winds
move inwards
• Both are curved
because of the Coriolis
Effect
Cyclones and Anticyclones
• The hole column of air around a high or low
pressure.
• Cyclones: when air moves into low areas it
collides or converges. The collision causes the air
to lifted and then diverge.
– Part of how storms are created
• Anticyclones: air converges towards the surface
and then once it reaches the surface it is forced
out (divergence)
– Nice weather
Global Wind Patterns
•
•
•
•
•
trade wind:
• Blow from east to west
• Latitudes 30º latitude to the
equator in both hemispheres
Westerlies:
• Blow from west to east
• between 30º and 60º latitude in
both hemispheres
• descending air moving toward the
poles is deflected by the Coriolis
effect
Polar easterlies:
• Blow from east to west
• between 60 and 90 latitude in both
hemispheres
• Surface winds created by the polar
high pressure are deflected by the
Coriolis effect
Each of the three types of winds are
affected by the High and Low pressures
Both winds and pressure zones have an
impacted on determining climates
around the global.
Dry air
Sinking
Moist
air rising
Dry air
Sinking
Moist
air rising
Dry air
Sinking
Dry air
Sinking
Moist
air rising
Jet Stream
• a narrow band of strong winds that blow in
the upper troposphere
• These wind exist in the Northern and
Southern Hemisphere.
– Subtropical jet stream.
– Polar jet streams:
• reach speeds of 500 km/h
• can affect airline routes and the paths of
storms.
HOW OCEAN ARE EFFECTED BY
WIND
How Global Winds Effect Ocean
Surface Currents
• Trade winds cause the ocean currents to be
pushed westward across the tropical latitudes
of all three major oceans.
• Westerlies cause the ocean currents to be
pushed eastward in the higher latitudes.
Coriolis Effect on Oceans
• Cause gyre
– Huge circle of moving ocean water found above
and below the equator
– Northern hemisphere they move clockwise
– Southern hemisphere they move
counterclockwise
El Nino
• Trade wind either weaken or switch direction
• Cause upwelling to weaken or stop off the
coast of South America and the fish die from
heat and lack of nutrient from the upwelling
process.
• Causes flooding in South America (Peru) and
droughts in Indonesia and Australia.
• Mess up the weather for the rest of the
Global.