Weather—Understanding it
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Transcript of Weather—Understanding it
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Weather—Understanding it
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Weather
Why is it so important to understand the weather?
Weather
Is the atmospheric conditions, along with short-term changes, of a certain place or certain time
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Tools to Measure Weather Thermometer- temperature Barometer- air pressure Anemometer- wind speed Rain gauge- rain fall Psychrometer- humdity
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Tools to measure Weather
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HEATING THE EARTH
Factors of the atmosphere that interact to cause weather Heat energy Air pressure Winds Moisture
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Heat Energy and the Atmosphere Most of the sun’s heat is absorbed
through the atmosphere. The sun’s radiant energy helps to
warm the atmosphere. It is reflected back into space
which can be Absorbed by clouds, earth’s
surface, scattered in the atmosphere, absorbed by ozone
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Air Pressure
Air pressure is the pressure that a column of air exerts on the surface below it.
Depends of the density of the air
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Factors affecting air pressure Three main factors
Temperature Water Vapor Elevation / altitude
High Pressure A large body of circulating
air with high pressure at its center and lower pressure outside of the system. (air moves into and down). Air moves from high
pressure to low pressure. This air is called wind.
The dense air sinks and brings clear skies and fair weather.
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Low Pressure A large body of circulating air
with low pressure at its center and higher pressure outside of the system.
Air on the outside of the system will spiral in toward the center.
This causes the air inside the system to rise causing the air to cool and condense.
Weather in this system is cloudy and rainy. 04/21/23 12
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Moisture in the Air
Humidity- the amount of water in the air
Relative humidity is the amount of water vapor present in the air compared to the maximum (100%) amount of water vapor the air could contain at that temperature
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Weather Patterns
Air masses– cover thousands of sq kilometers
Air masses are formed from changes in weather causing large bodies of air to move.
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Four types of air masses
Maritime Tropical– forms over ocean near equator Holds warm moist air When in contact with cold air in
winter- snow or rain fall Maritime Polar– forms over the Pacific
Ocean in both winter and summer Brings cooler weather to the eastern
states and fog to the western states.
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Air masses
Continental Tropical– forms over land in Mexico. Brings hot, dry air to the SW states.
Continental Polar- forms over land in Northern Canada In winter, brings cold, dry air to the
US.
http://video.about.com/weather/Types-of-Air-Masses.htm
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FRONTS
When 2 air masses such as warm and cold meet they form a boundary instead of mixing. FOUR TYPES OF FRONTS
Cold Warm Occluded Stationary
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fronts
Cold– meet and push under a warm mass of air Travels faster than a warm front
Warm– overtakes a cold front and moves over it
Occluded– when cool air overtakes a cold front and warn air is pushed upward.
Stationary– two fronts meets but do not move.
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Lines on a Map
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