Transcript 115291_Weather.pptx

Weather
Climate vs Weather

Weather - daily
condition of the earths
atmosphere

Climate – Average
weather conditions over
an extended period of
time
Cause of Climate
Earths Climate Zones:
• Polar
• Temperate
• Tropic

Other things that influence climate:
 Elevation
 Topography
 Mountains
 Flat
lands
 Hills
 Near
water
Back to weather

Factors that cause weather:
A.
Weather – is the present state of our atmosphere.
B.
What causes our weather?
1.
C.
The interaction between the earth’s air, water, land and sun causes
the changes in our weather.
There are 4 factors that determine the type of weather we receive:
1.
Temperature
2.
Air Pressure
3.
Wind
4.
Amount of moisture in the air

Heat Transfer on Earth:
A.
The way the earth is heated controls the characteristics of the
atmosphere.
B.
Heat moves through earth in three different ways:
C.
1.
Radiation
2.
Conduction
3.
Convection
Radiation – Energy that comes off of the sun and is absorbed by the
earth
1.
When a surface on earth comes into contact with this radiation it
either absorbs it or deflects it away.
2.
If it absorbs it the surface will change it into heat.
D.
E.
Conduction- The transfer of heat when molecules collide into
each other.
1.
Molecules in hot objects move toward the molecules in cold objects.
2.
Heat is transferred to the colder object until the molecules are all the
same temperature.
3.
Ex. Frying pan on a stove.
Convection- The transfer of heat through convection currents.
1.
Hot molecules are less dense than cold molecules.
2.
A hot fluid will rise and a cold fluid will sink.
3.
This causes convection currents.
4.
Ex. Water boiling on a stove.

Air pressure:
A.
Air Pressure – The weight of the atmosphere as it pushes down on
earth’s surface.
B.
Three factors that determine air pressure:
1.
Temperature of the air.
A.
2.
Density of the air. (elevation)
A.
3.
The higher the temperature, the lower the air pressure
The higher the density, the higher the pressure.
The amount of water vapor. (humidity)
A.
The higher the humidity, the lower the pressure.

Wind:
A.
B.
Why do we get different wind systems?
1.
Uneven heating of the earth causes different air temperatures.
2.
That can change air pressure.
3.
Wind blows from areas of high pressure to areas of low pressure.
Coriolis Effect
1.
This also will affect wind systems.
2.
Coriolis Effect- is the result of the earth’s eastward rotation.
3.
It pushes winds in the northern hemisphere to the right
(clockwise), and to the left (counter clockwise) in the southern
hemisphere.
C. The Different Wind Systems:
1. Winds are named for the direction they blow from.
2. There are four global wind zones on earth.
A.) Doldrums-
Windless zone of the earth that is located in the
0 to 5 degree latitudes.
Blow from east to west and are located
“Northeast B.) Trade Windsbetween 5 to 30 degrees North or South
or
latitude.
Southeast
Trade
Winds”
C.) Prevailing WesterliesBlow from west to east located
Responsible for our
weather.
D.) Polar Easterlies-
between 30 to 60 degrees north
or south latitude.
Blow from east to west and are
located between 60 to 90 degrees
north or south latitude.
D. Minor or Local Wind Systems:
1. Earth also has some local wind systems that affect our weather.
2. Jet Stream-
Narrow belts of strong winds in the upper
troposphere.
A.) There are two jet streams in each hemisphere.
B.) They can change position daily.
C.) When they do they have a major influence on weather.
3. Sea Breeze-
Cold winds blowing from the water to the land.
A.) It is a convection current of wind caused by the land warming
faster during the day than the water does.

The amount of moisture in the air:
A. Water cycle – go over on later
B. Humidity – the amount of water in the air.
1.
C.
Why can air hold water
A.
Air acts like a sponge
B.
Holes in the sponge allow it to hold water.
C.
Air holds water in a similar way
D.
Water fits into the spaces between the molecules of air.
E.
When the air can’t hold any more water clouds start to form.
Relative humidity – Compares the actual amount of water vapor in the air with the
maximum amount of water vapor the air can hold
A.
Relative humidity is expressed as a %
B.
If the relative humidity is 100 % the air can not hold any more water.
C.
Saturation- When air contains as much moisture as possible
D.
Additional water added to the air will condense back to a liquid, depending on the
temperature.
E.
Dew point – The temperature at which air is saturated and water vapor in the air
condenses
D.
Two things determine relative humidity:
1.
Temperature of the air.
A.
2.
Warm air con hold more moisture than cold air.
The amount of moisture added or subtracted into an
area.
A.
Ex. Bathroom after a shower.
Continuing
Weather
Making Sense of Our Data

Temperature

Precipitation

Air Pressure

Cloud Cover

Wind

Humidity

Dew point
Information from wind
4
Types of Fronts
Cold
Warm
Occluded
Stationary
Fronts
Making Sense of Our Data

Temperature

Precipitation

Air Pressure

Cloud Cover

Wind

Humidity

Dew point
Temperature

Hot temperatures results:

Air molecules move faster

Cole temperatures results:

Air mass may rise




Lower pressure
Air can hold more moisture
Air molecules move slower
Air mass may sink

Higher pressure

Air can hold less moisture

Dew point may be reached
and condensation occurs
Precipitation

We will go over what happens tomorrow during the water cycle.
Air Pressure
Cloud Cover

Go through tomorrow during water cycle
Winds

What are winds caused by?
Humidity

Relative humidity
Dew Point

Temperature at with air is 100% saturated and water condensates.