Meteorology Regents Earth Science St. Martin de Porres School Mrs. Canfield.
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Transcript of Meteorology Regents Earth Science St. Martin de Porres School Mrs. Canfield.
MeteorologyMeteorology
Regents Earth ScienceRegents Earth ScienceSt. Martin de Porres SchoolSt. Martin de Porres School
Mrs. CanfieldMrs. Canfield
Meteorology vs. WeatherMeteorology vs. Weather
MeteorologyMeteorology is the study of atmospheric is the study of atmospheric phenomenonphenomenon
WeatherWeather is the current state of the is the current state of the atmosphere in a given areaatmosphere in a given area
Air MassesAir Masses
An air mass is a large body of air that takes An air mass is a large body of air that takes on the characteristics of the area over which on the characteristics of the area over which it forms.it forms.
Classification of air masses considers Classification of air masses considers whether the air mass is cold or warm, dry or whether the air mass is cold or warm, dry or humidhumid
Classification of Air MassesClassification of Air Masses
cT – continental tropical air mass. Warm cT – continental tropical air mass. Warm and dry. Mexicoand dry. Mexico
mT – maritime tropical air mass. Warm and mT – maritime tropical air mass. Warm and humid. Gulf of Mexico or Caribbeanhumid. Gulf of Mexico or Caribbean
Air masses -- continuedAir masses -- continued
cP – continental polar air mass. Cold and cP – continental polar air mass. Cold and dry. Interior Canada and Alaskadry. Interior Canada and Alaska
mP – maritime polar air mass. Cold and mP – maritime polar air mass. Cold and humid. North Atlantic and Pacifichumid. North Atlantic and Pacific
A – artic air mass. Similar to cP, but much A – artic air mass. Similar to cP, but much colder. North of Canadacolder. North of Canada
See reference tables for more information!See reference tables for more information!
Air masses move because of windsAir masses move because of winds
As air masses move, they are modified by As air masses move, they are modified by the regions over which they movethe regions over which they move
Wind Systems move air massesWind Systems move air masses
In theory, convection would cause air to In theory, convection would cause air to warm and rise at the equator, move north or warm and rise at the equator, move north or south as it cools, and sink near the poles.south as it cools, and sink near the poles.
Convection currents would cause air at the equator to rise and move towards the coolerpoles.
Air at the poles is cooler and denser, so it sinks and displaces warmer tropical air
Rotations of Earth affect windsRotations of Earth affect winds
Coriolis effectCoriolis effect —Particles in the Northern —Particles in the Northern hemisphere is deflected to the right. hemisphere is deflected to the right. Particles in the Southern hemisphere is Particles in the Southern hemisphere is deflected to the left. This is due to the deflected to the left. This is due to the rotation of Earth.rotation of Earth.
http://whyfiles.larc.nasa.gov/text/kids/Problem_Board/problems/light/images/atmosphere04.gif
http://earthguide.ucsd.edu/virtualmuseum/images/AtlanticGyresWesterliesTradeWinds.jpg
Three major wind systemsThree major wind systems
Trade winds – occur at 30Trade winds – occur at 30oo north and south north and south latitude. Northeast to southwest in the latitude. Northeast to southwest in the Northern hemisphereNorthern hemisphere
Prevailing westerlies – occur between 30Prevailing westerlies – occur between 30oo and 60and 60oo north and south latitude. Circulation north and south latitude. Circulation pattern is opposite that of the trade windspattern is opposite that of the trade winds
Wind systems--continuedWind systems--continued
Polar easterlies – occur between 60Polar easterlies – occur between 60oo latitude latitude and the poles. Circulation is similar to that and the poles. Circulation is similar to that of the tradewindsof the tradewinds
http://gpc.edu/~pgore/Earth&Space/images/globalcirculation.jpg
Winds are affected by temperature Winds are affected by temperature and pressureand pressure
Wind blows from an area of high pressure to Wind blows from an area of high pressure to an area of low pressurean area of low pressure
Pressure is affected by temperaturePressure is affected by temperature– Remember! Heat causes air to expand. This Remember! Heat causes air to expand. This
increases pressure.increases pressure.
Jet StreamsJet Streams
Jet streams are caused by the differences in Jet streams are caused by the differences in temperature and pressure that exist temperature and pressure that exist between surface and upper level airbetween surface and upper level air
Remember!Remember!
Weather systems move from west to east in Weather systems move from west to east in North AmericaNorth America
This related to the prevailing westerlies and This related to the prevailing westerlies and the jet streamthe jet stream
FrontsFronts
A front is a narrow region separating two air A front is a narrow region separating two air masses of different densitiesmasses of different densities
Density of an air mass is related to Density of an air mass is related to temperature, pressure and humiditytemperature, pressure and humidity
http://research.utep.edu/Portals/72/weather%20NOAA/fronts%20vert.GIF
Cold frontsCold fronts
Cold, dense air displaces warm air and Cold, dense air displaces warm air and forces the warm air up along a steep front. forces the warm air up along a steep front.
Usually associated with unstable weatherUsually associated with unstable weather
http://www.pagasa.dost.gov.ph/genmet/fronts/coldfront.gif
Warm frontsWarm fronts
Warm air displaces cold air. Associated Warm air displaces cold air. Associated with cloudiness and precipitationwith cloudiness and precipitation
http://www.pagasa.dost.gov.ph/genmet/fronts/warmfront.gif
Stationary frontStationary front
Two air masses meet and stall. Air between Two air masses meet and stall. Air between the masses does not move.the masses does not move.
Usually involves air masses that have been Usually involves air masses that have been modifiedmodified
Occluded frontOccluded front
A warm air mass is squeezed up between A warm air mass is squeezed up between two cold air masses. It gets stuck up on toptwo cold air masses. It gets stuck up on top
http://www.coolweather.co.uk/htdocs/fronts.htm
Pressure systemsPressure systems
High pressure– air sinks and spreads away High pressure– air sinks and spreads away from Earth’s surface. It is deflected from Earth’s surface. It is deflected clockwise by the Coriolis effectclockwise by the Coriolis effect
High pressure systems are usually High pressure systems are usually associated with pleasant weatherassociated with pleasant weather
Pressure systemsPressure systems
Low pressure – air rises and is replaced by Low pressure – air rises and is replaced by air from outside the system. air from outside the system.
Low pressure systems are usually Low pressure systems are usually associated with poor weather conditions associated with poor weather conditions
Remember!Remember!
Winds blow in to a low pressure systemWinds blow in to a low pressure system Winds blow away from a high pressure Winds blow away from a high pressure
systemsystem
Weather toolsWeather tools
Thermometer—measures temperatureThermometer—measures temperature Barometer—measures air pressureBarometer—measures air pressure Anemometer—measures wind speed and Anemometer—measures wind speed and
directiondirection Hygrometer—measures humidityHygrometer—measures humidity
Station modelsStation models
Station models are used to depict the data Station models are used to depict the data collected at a weather stationcollected at a weather station