Download - Air Pressure/Winds
![Page 1: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/1.jpg)
Air Pressure/Winds• Air Pressure –weight of the atmosphere
pushing down on Earth (we don’t feel it because air is pushing on all sides, not just down from the top.)
• •Barometer–tool that measures air pressure.• –Use millibarsto show pressure on maps = they makeisobars when connected.
![Page 2: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/2.jpg)
Connect the same numbers to draw in the isobars.
![Page 3: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/3.jpg)
So why does air pressure change?
• Elevation – in general, the higher the elevation, the lower the pressure (less pressure to push down on, since you are higher)
• Temperature warm air lowers pressure (it rises and particles move farther apart), and may get rain . Cool air gives increase in pressure, and weather is clearer .
• Humidity – the more water vapor air contains, the lighter the air is = so low pressure. (Remember: warmer air can hold more water vapor and is low pressure)
![Page 4: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/4.jpg)
Reading Pressure on a Map• Isobars = lines showing air having the same pressure.• High pressure area (or a High ) –Rotates clockwise .• Low pressure area (or a Low ) –Rotates counterclockwise .• Pressure gradient = • –Lines close together show that pressure is quickly changing (and we will have strong winds).Lines further apart shows weakpressure gradient (and we will have weak winds).
![Page 5: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/5.jpg)
![Page 6: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/6.jpg)
Winds Blow Because…• Air flows from an area of High pressure to an area of Low
Pressure H to
L
• Coriolis Effect -the apparent curve of a moving object due to the Earth’s rotation
–Causes curve to the right in the Northern Hemisphere –Causes curve to the left in the Southern Hemisphere • Jet Stream – fast moving winds near the top of the
troposphere (winds 120-240 kph) –In the US the jet streams supplies energy to storms and directs their paths.• Anemometer–tool that measures wind speed .
![Page 7: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/7.jpg)
![Page 8: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/8.jpg)
Global Wind Patterns• Doldrums or Intertropical Convergence Zone (ITCZ) –Low
pressure in tropics –Hot, humid, little to no wind, rain is common.• Subtropical highs or Horse Latitudes –between 20-35
degrees –Deserts –because sinking cooler air with no precipitation is near.• Tradewinds–between 35-60 degrees latitude –Warm, steady, winds• Polar highs –High pressure above 60 degrees latitude (in
the poles) –Where cold air sinks at the poles, usually easterly surface winds.
![Page 9: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/9.jpg)
Questions
• Which global wind pattern do we live in?The westerlies
• How are the winds named?from the direction they came from
![Page 10: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/10.jpg)
Global Wind Patterns
![Page 11: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/11.jpg)
Effects of seasons on winds…
• With a change in air pressure the direction of winds changes
• So winds change direction with the seasons . –Monsoons• Occur southern Asia• Heavy rains
![Page 12: Air Pressure/Winds](https://reader035.vdocument.in/reader035/viewer/2022062222/56815ac5550346895dc8922b/html5/thumbnails/12.jpg)
Local Winds: Land Breeze –vs- Sea Breeze
• Sea Breeze - occurs during the day • Coastal land is warmer than water, causing decrease in pressure
over land • So breeze flows from High to Low/from Sea to Land . (cool breeze from sea blows inland)
• Land Breeze – Occurs at night • Air over land is colder than air over water, causing decrease in pressure over the water. • So, breeze flows from High to Low/from Land to Sea__ (cool
breeze from land blows to sea)