Factors That Influence Weather

Mr. Silva

Ag Earth Science

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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 to colder

regions of the earth.

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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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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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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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Factors that Influence Weather

• Altitude

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Factors that Influence Weather

• Angle of Sunlight– areas closest to the equator receive the most

direct angle of sunlight

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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 effect 10

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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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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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Factors that Influence Weather

• Fronts– when two air masses meet, the boundary

between them is a front

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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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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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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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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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Ohio...all year long

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California...9 months a year

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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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Factors that Influence Weather

• Plate Tectonics– climate change through greenhouse effect

• How??? We know this.• Short and long term.

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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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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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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– convection cells 26

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Factors that Influence Weather

• Human Activity– Deforestation– Urbanization– Release of

Pollutants--greenhouse gases

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