Weather is influenced by many factors including air masses, air pressure, sunlight, greenhouse gases, moisture, mountains, oceans, wind patterns, and human activity. Climate describes weather trends over many years and is impacted by radiation, conduction, convection, altitude, latitude, proximity to oceans, and landmass distribution. Fronts form where different air masses meet and influence local weather conditions.

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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