Ce diaporama a bien été signalé.
Le téléchargement de votre SlideShare est en cours. ×

Weather ms ppt 1997

Prochain SlideShare
Weather
Weather
Chargement dans…3
×

Consultez-les par la suite

1 sur 32
1 sur 32

Plus De Contenu Connexe

Livres associés

Gratuit avec un essai de 30 jours de Scribd

Tout voir

Livres audio associés

Gratuit avec un essai de 30 jours de Scribd

Tout voir

Weather ms ppt 1997

  1. 1. Weather... You can’t see me, but you feel me, you can’t touch me, but I can touch you. I have been called the “Breathe of the Gods”, or the killer and giver of life, gentle and fierce, friendly and enemy, angry and happy. The Native Americans called me Moriah, and Snow Eater (Chinook). The Japanese call me Kaze and in Russia I am called Veter. I can shatter homes, or wake a child from a peaceful sleep or bring relief in times of need. I can spread the most dreaded diseases or bring a welcome freshness. What am I?
  2. 2. Weather is....  The current state of the atmosphere...what is happening right now
  3. 3. Main points to remember as we learn about weather:  The sun warms the earth’s surface and therefore all the air above the surface  The earth is warmed most at the equator and least at the poles---why?  The air above land is warmed more quickly than air above water.  Warm air expands and rises, creating an area of low pressure; cold air is dense and sinks, creating an area of high pressure
  4. 4. Weather Factors  Weather: The state of the atmosphere at a specific time and place TEMPERATURE= the average motion of molecules ↑ TEMP= ↑movement of molecules= feels hot ↓ TEMP= ↓movement of molecules= feels cold
  5. 5. Air Pressure  Warm air= expanding or rising air= leaves behind L pressure  Cold Air=sinking air= leaves an area of H pressure
  6. 6. Wind MovementWind Movement  Uneven heating ofUneven heating of the earth’s surfacethe earth’s surface causes some areascauses some areas to be warmer thanto be warmer than others.others.  As we know, warmAs we know, warm always follows coldalways follows cold to share it’s warmth-to share it’s warmth- when this happenswhen this happens in the atmosphere,in the atmosphere, wind happens!wind happens!
  7. 7. What causes winds?  A wind is aA wind is a horizontalhorizontal movement of airmovement of air from a area of highfrom a area of high pressure to an areapressure to an area of low pressureof low pressure  It is this difference inIt is this difference in pressure that makespressure that makes the air move=windthe air move=wind  Winds are measured by direction and speed  The anemometer is the tool we use to measure this  Wind chill=↑ cooling the wind causes
  8. 8. Local WindsLocal Winds  The land cools and heats faster than the ocean. Water holds heat longer than land, and takes longer to heat or cool. SEA BREEZE During the day, the land gets hotter faster than the water. The heated air rises, leaving behind an area of low pressure. Wind from the cooler sea blows in to take the place of that warmer air. These happen during the day!
  9. 9. Land BreezesLand Breezes At night the lands cools off faster than the sea. Cool air sinks creating an area of high pressure. Wind blows from the land to the sea.
  10. 10. Global Circulation and WindGlobal Circulation and Wind SystemsSystems Solar energy is at itsSolar energy is at its greatest around thegreatest around the equator---Why?equator---Why?
  11. 11. Global Winds:  Wind belts: Horse Latitudes= 30°N and S of equator =calm winds= worlds desert areas Jet Streams= 10km above the surface blow from the west to the east
  12. 12. Intense heat = Powerful CONVECTION  Warm, moist air rises and leaves behind anWarm, moist air rises and leaves behind an area of low pressure. This is why most rainarea of low pressure. This is why most rain forests are found along equatorial regions.forests are found along equatorial regions.  That air rises until it reaches the top of theThat air rises until it reaches the top of the troposphere, where it can’t rise any further.troposphere, where it can’t rise any further.  It spreads out towards the polar regions HOTIt spreads out towards the polar regions HOT follows COLD wanting to share its warmth.follows COLD wanting to share its warmth.  As it spreads it begins to cool and sink-As it spreads it begins to cool and sink- usually 30usually 30°N and S of the equator- sinking°N and S of the equator- sinking air produces an area of H pressure with dryair produces an area of H pressure with dry conditions= desert regions on earthconditions= desert regions on earth
  13. 13. Some or the air moves back towards the equator as it sinks...  Tradewinds: Where do you think they got their name? Who were these winds particularly important to?
  14. 14. There was an area that sailorsThere was an area that sailors avoided with their lives...avoided with their lives...  THE DOLDRUMS...THE DOLDRUMS... is the area aroundis the area around the equator wherethe equator where the wind completelythe wind completely dies out... whichdies out... which meant death asmeant death as soon as the freshsoon as the fresh water ran out.water ran out.
  15. 15. Water in the Atmosphere:Water in the Atmosphere: HumidityHumidity  HumidityHumidity: measure of the amount of water vapor: measure of the amount of water vapor stuck between molecules in the air. The air’s abilitystuck between molecules in the air. The air’s ability to hold water depends on the air tempto hold water depends on the air temp  The hotter the air, the more water the air can holdThe hotter the air, the more water the air can hold  Cold air: molecules move slower so droplets of waterCold air: molecules move slower so droplets of water can start to stick together=can start to stick together=condensationcondensation  Relative humidityRelative humidity: the amount of water vapor(%): the amount of water vapor(%) compared to the amount the air can hold- tool used iscompared to the amount the air can hold- tool used is aa psychrometer.psychrometer.  100%=air is saturated100%=air is saturated
  16. 16. Cloud Formation  Clouds form when water vapor condenses on dust, salt particles in the air  The temperature in which condensation begins is called the dew point
  17. 17. TYPES OF CLOUDS  Cirrus Clouds: wispy, feathery clouds Form only at high levels, therefore are made of ice crystals
  18. 18. Types of Clouds  Cumulus Clouds: are puffy white cotton ball looking clouds
  19. 19. Cumulonimbus Clouds  These are thunderstorm clouds
  20. 20. Types of Clouds  Stratus Clouds: clouds that form in flat layers- cover all or most of the sky and are low level clouds
  21. 21.  Air masses are masses of air that have the same characteristics of the surface over which it develops  Pressure Systems descending (going down)=H pressure ascending (going up)=L pressure Air Masses
  22. 22. Weather Foldable  Warm front  Cold front  Occluded front  Stationary Front
  23. 23. Fronts: the boundary between 2 air masses  Warm Front: warm air slides over departing cold air- large bands of precipitation form This is the symbol on a map for a warm front
  24. 24. Cold Fronts  Cold air pushes under a warm air mass. Warm air rises quickly=narrow bands of violent storms form This is the symbol for a cold front
  25. 25. Occluded Front  2 air masses merge and force warm air between them to rise quickly. Strong winds and heavy precipitation will occur This is the weather map symbol for an occluded front
  26. 26. Stationary Front  Warm or cold front stops moving. Light wind and precipitation may occur across the front boundary This is the weather map symbol for a stationary front
  27. 27. Reading a weather map  ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure
  28. 28. Reading a weather map...  Isotherm: Connects areas of equal temperature; therm means temperature
  29. 29. Weather Station (not on the TV)

×