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ClimateClimateFactors that influence the weather
WeatherWeatherandandClimateClimate
Climate is the long-term trend of Climate is the long-term trend of temperature and precipitation (rain, snow). temperature and precipitation (rain, snow). Weather is the day-to-day variation in Weather is the day-to-day variation in temperature and precipitationtemperature and precipitation.
TEKS Obj. 4a - TEKS Obj. 4a - Explain the distribution of different types of climate Explain the distribution of different types of climate in terms of patterns of temperature, wind, and precipitation.in terms of patterns of temperature, wind, and precipitation.
• LLatitudeatitude• AAir Pressureir Pressure• MMountain Barriers/topographyountain Barriers/topography• EElevationlevation• CContinental Locationontinental Location• OOcean currentscean currents• prevailing prevailing WWind directionind direction• SStormstorms
The climate where you live is called The climate where you live is called regional climateregional climate. . It is the average weather in a place over more than It is the average weather in a place over more than thirty years. The acronym LAMECOWS helps you to thirty years. The acronym LAMECOWS helps you to remember the factors influencing climate including:remember the factors influencing climate including:
solar solar radiationradiation
One unit of One unit of solar energy solar energy strikes the strikes the Earth most Earth most directly at the directly at the equator and equator and is spread over is spread over a given area. a given area. The same unit of energy that strikes the pole is The same unit of energy that strikes the pole is spread over a larger area. Consequently, the spread over a larger area. Consequently, the equator heats up more than the poles.equator heats up more than the poles.
The chief factor that determines climate is the The chief factor that determines climate is the distance a place is from the equator in terms of distance a place is from the equator in terms of Latitude. The closer a place is to the equator, Latitude. The closer a place is to the equator, the warmer it will be.the warmer it will be.
heat heat transfertransfer
Heat in the atmosphere is transferred via greater heating of the atmosphere over the equator which causes airto expand, become less dense and rise; as it rises it releases its water vapor -- this is a
permanent low pressure belt
the tropicsthe tropicsBecause of the Because of the earth’s 23 ½ ° tilt, earth’s 23 ½ ° tilt, four more four more imaginary lines imaginary lines delineate the polar delineate the polar and tropical and tropical regions: the Arctic regions: the Arctic and Antarctic and Antarctic Circles, and the Circles, and the Tropics of Cancer Tropics of Cancer and Capricorn, and Capricorn, each at 23 ½° from each at 23 ½° from their respective their respective poles and the poles and the Equator. Equator.
The Antarctic Circle (not shown) The Antarctic Circle (not shown) is at 23 ½° from the South Pole is at 23 ½° from the South Pole or 66 ½° South latitude.or 66 ½° South latitude.
In a cyclone (low-pressure cell) air converges In a cyclone (low-pressure cell) air converges and rises. In an anticyclone cell, (high pressure and rises. In an anticyclone cell, (high pressure cell) air descends and diverges.cell) air descends and diverges.
“Highs” descend
“Lows” ascend
low, middle, high low, middle, high latitudeslatitudes
This diagram shows one way the Earth's surface This diagram shows one way the Earth's surface can be divided into regions according to can be divided into regions according to latitude. It is helpful to refer to latitude. It is helpful to refer to a place as being a place as being in the in the lowlow, , middlemiddle, , or or highhigh latitudes. latitudes. Heated air that Heated air that rises from the rises from the tropics descends tropics descends at latitudes 30°, at latitudes 30°, 60°, and at the 60°, and at the poles.poles.
Coriolis EffectCoriolis EffectFigure 1: In the inertial Figure 1: In the inertial frame of reference frame of reference (upper part of the (upper part of the picture), the black picture), the black object moves in a object moves in a straight line. However, straight line. However, the observer (red dot) the observer (red dot) who is standing in the who is standing in the rotating frame of rotating frame of reference (lower part of reference (lower part of the picture) sees the the picture) sees the object as following a object as following a curved path. curved path.
prevailing prevailing wwindsindsThe Coriolis The Coriolis effect means effect means that winds that winds caused by caused by atmospheric atmospheric highs and highs and lows do not lows do not move straight move straight north-south, north-south, but appear to but appear to bend relative bend relative to the earth’s to the earth’s rotation.rotation.
Text pg. 54Text pg. 54
Climactic ZonesClimactic Zones
Hadley cellsHadley cells
wind wind beltsbeltsThe currents in the high, middle, and low latitudes produce predictable wind currents that ancient sailors knew well.
topography – topography – the shape of the earth’s surfacethe shape of the earth’s surface
If not for landforms and topography, the Coriolis If not for landforms and topography, the Coriolis Effect would appear as in the diagram at left. Effect would appear as in the diagram at left. The actual wind directions are shown on the The actual wind directions are shown on the right side globe.right side globe.
surface surface oocean cean currentscurrents
This illustration shows the circulation of the This illustration shows the circulation of the oocean's surface water. Names of the major cean's surface water. Names of the major oocean cean currents are noted with warm currents are red currents are noted with warm currents are red and cold currents blue.and cold currents blue.
The weather in this otherwise cold climate zone, The weather in this otherwise cold climate zone, is moderated by the effects of The North is moderated by the effects of The North Atlantic Drift which originates from the Gulf Atlantic Drift which originates from the Gulf Stream along North America and from the Stream along North America and from the northern Sargasso Sea.northern Sargasso Sea.
North North AtlantiAtlantic Driftc Drift
Its effect is Its effect is sufficient to sufficient to cause cause certain parts of certain parts of the west of the west of Britain and Britain and Ireland to be an Ireland to be an average of average of several degrees several degrees warmer than warmer than most other parts most other parts of those of those countries.countries.
Gulf Gulf StreamStream False-color
image of the temperature of the Gulf Stream
Prevailing Prevailing wwinds inds push air from oceanpush air from oceancurrents over landcurrents over land
What factors What factors contribute to contribute to the patterns of the patterns of heavy and light heavy and light rainfall on this rainfall on this map?map?
Consider Consider WWind ind and and OOcean cean currents, currents, MMountain ountain barriers andbarriers and CContinental ontinental LocationLocation
Climate Climate ZonesZones
Compare this map with the previous one showing rainfall. What Compare this map with the previous one showing rainfall. What physical feature most obviously affects rainfall patterns? physical feature most obviously affects rainfall patterns?
Comparing marine climatesComparing marine climates
The significant difference The significant difference between climate between climate characteristics of Vancouver characteristics of Vancouver and London, both Marine and London, both Marine West Coast climates, arises West Coast climates, arises from location, local from location, local topography, and ocean topography, and ocean current influence.current influence.
The dry summer in The dry summer in Vancouver is due in part to Vancouver is due in part to subsiding, subtropical high subsiding, subtropical high pressure lying to the south. pressure lying to the south. Precipitation is nearly Precipitation is nearly double that of London due double that of London due to local to local orographic uplift of uplift of air.air.
Orographic EffectOrographic Effect text pg. text pg. 5050
Mountain ranges force moisture-laden clouds to Mountain ranges force moisture-laden clouds to release precipitation as they rise up the windward side.release precipitation as they rise up the windward side.
mapping mapping precipitationprecipitation
The high precipitation The high precipitation totals are located on the totals are located on the western side of the western side of the Cascade mountains, while Cascade mountains, while the extremely low the extremely low precipitation totals are on precipitation totals are on the eastern, or the eastern, or lee side of the mountain range.
Average annual Average annual precipitation for the precipitation for the state of Washington state of Washington shows that within a shows that within a distance of 250 distance of 250 miles, annual miles, annual precipitation totals precipitation totals change from more change from more than 180”/yr. (deep purple) than 180”/yr. (deep purple) to less than 10”/yr. (bright to less than 10”/yr. (bright red). This distribution is a red). This distribution is a direct result of the direct result of the topography of the land.topography of the land.
Like directors Like directors on a globular on a globular stage, the stage, the ocean currents ocean currents determine determine where heavy where heavy rains will fall rains will fall spreading the spreading the equator’s heat equator’s heat to all corners of to all corners of the earth.the earth.
ocean ocean currents currents direct rainfalldirect rainfall
WWinds begin with differences in inds begin with differences in aair pressures. ir pressures. Pressure that's higher at one place than another Pressure that's higher at one place than another sets up a force pushing from the high toward the sets up a force pushing from the high toward the low pressure. The greater the difference in low pressure. The greater the difference in pressures, the stronger the force. pressures, the stronger the force.
WWindsinds
LinksLinks
• http://www-class.unl.edu/geol101i/15a_climate.htm• http://en.wikipedia.org/wiki/Coriolis_effect• http://pariskillton.blogspot.com/2007/04/windy.html• http://library.thinkquest.org/5818/globalwinds.html
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