1. Factors That Influence
Weather
Mr. Silva
Ag Earth Science

2. Weather and Climate
• Weather is caused by movement or transfer of
heat energy, which influences temperature,
humidity, precipitation, cloud cover, wind speed
and wind directions.
• Climate describes the total of all weather
occurring over a period of years in a given
place.
– Radiation is how the earth receives solar energy
– Conduction is energy transferred by collisions in heat
carrying molecules
– Convection is energy transferred from hotter to2colder
regions of the earth.

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4. Factors that Influence Weather
• Air Mass
– large body of air that has similar temperature
and moisture content
– Categorized
• equatorial
• tropical
• polar
• arctic
• continental
• maritime
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5. Factors that Influence Weather
• Air Pressure
– gravity on air mass (99% within 20 miles of
Earth’s surface)
– measured in millibars, Torr, or hectopascales,
or kilopascals (kPa)
– low pressure produces stormy weather
• (usually)
– high pressure produces fair weather
• (usually)
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6. Factors that Influence Weather
• Albedo
– is reflectivity.
• ocean = low albedo
• snow and ice = high albedo
• dust = high albedo (solar radiation does not even
hit the Earth’s surface)
• Critical thinking??
– When has the earth been the coolest?
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8. Factors that Influence Weather
• Altitude
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9. Factors that Influence Weather
• Angle of Sunlight
– areas closest to the equator receive the most
direct angle of sunlight
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10. Factors that Influence Weather
• Carbon Cycle
– The element
carbon and
molecule carbon
dioxide trap and
hold heat energy
• Consumption of
C02 has a cooling
effect
• Production of C02
has a heating
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effect

11. Factors that Influence Weather
• Clouds
– collections of water droplets or ice crystals
that are suspended in air
• How? As warmer air rises, it expands due to
decreasing pressure, thus drops in temperature =
cannot hold as much water vapor.
• Vapor condenses forming water particles or ice
crystals.
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13. Factors that Influence Weather
• Distance to Oceans
– Oceans are thermally more stable than
landmasses.
– Changes in temperature are more extreme in
the middle of the continents
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14. Factors that Influence Weather
• Fronts
– when two air masses meet, the boundary
between them is a front
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15. Factors that Influence Weather
• Greenhouse Effect
– Earth’s ability to trap and contain heat energy
• without it life could not exist, too much we burn up
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16. Factors that Influence Weather
• Heat (Convection)
– climate is influenced by how heat energy is
exchanged between air over oceans and over
land.
• Land Changes
– climate is influenced by urbanization and
deforestation
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17. Factors that Influence Weather
• Landmass Distribution
– Ocean water is much more absorbent than
landmasses. Landmasses reflect more solar
radiation than land. What does than mean?
• Latitude
– higher latitudes = less solar radiation
• Location
– climate is influenced by the location of high
and low air pressure zones and where
landmasses are distributed 17

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19. Factors that Influence Weather
• Moisture Content of Air (Humidity)
– this determines plant growth, distribution, and
is a major determinant of biome type.
• What the hell does that mean?
• Where is the most humidity in the world?
• Why are there no sprinkler systems in Ohio?
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20. Ohio...all year long
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21. California...9 months a year
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22. Factors that Influence Weather
• Mountain Ranges
– Mountain effect weather! So, ha!
– The ocean facing side (the windward side) will
receive more rain.
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23. Factors that Influence Weather
• Plate Tectonics
– climate change through greenhouse effect
• How??? We know this.
• Short and long term.
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24. Factors that Influence Weather
• Pollution
– greenhouse gases are emitted from both
natural and human made sources.
• What do greenhouse gases do?
• Name three.
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25. Factors that Influence Weather
• Rotation
– Day and night, heat escapes from the Earth’s
surface at night. The daily minimum
temperature occurs just before sunrise.
• So, you will be coldest when you wake up when
you are camping. Wear those booties!
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26. Factors that Influence Weather
• Wind Patterns
– Wind patterns are influenced by temperature
and pressure differences (gradients)
• sun heats atmosphere unevenly
• air closest to surface is warmer and rises
• high elevations air is cooler and sinks =
convection---> primary cause of winds
• global air circulation is caused and affected by:
– uneven heating of Earth’s surface
– seasons
– the Coriolis effect
– solar radiation
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– convection cells

27. Factors that Influence Weather
• Human Activity
– Deforestation
– Urbanization
– Release of
Pollutants--
greenhouse
gases
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