19A: Weather
• Wind power: clean energy
• Wind farms: Many turbines
• Supply electricity
19.1http://www.shoener.com/waymart-wind-farm. html
View from the blade of a turbinehttp://www.viewpure.com/iwHpGw665NA?start=0&end=0
Weather
• Weather: the condition of Earth’s atmosphere at any given time and place
• Meteorology: The study of the atmosphere
• Collect data to describe and predict weather 19.2
https://graphical.weather.gov/images/conus/M axT1_conus.png
Weather• Temperature
•Amount of thermal energyin the air
-Thermometers
-Thermographs 19.2
https://www.princeton.edu/sites/defaul t/files/styles/1 x_full_2 x_half_ crop/public/images/20 18/07/I SOIS_still_2_d.jpg?itok=D7a 96C66
https://www.sksato.co.jp/modules/shop/product_info. php?products_i d=312&langua ge=engl ish
Weather
• Temperature scales are linked to constant physical conditions
• Fahrenheit scale
• Water freezes at 32°
• Water boils at 212°
19.2https://mywritinghome.wordpress.com/2017/0 7/27/ne ver-wa lk-awa y-from-a -boiling -pot/
Weather
• Temperature
• Celsius scale
• Water freezes at 0°
• Water boils at 100°
• A Fahrenheit degree is “smaller” 19.2
• Pressure:
• Force exerted by air on a standard area
• Changes with temperature, elevation
• hot air: less pressure
• Top of a mountain: less pressure 19.2http://www.viewpure.com/MYswNGN5Gc8?start=0&end=0
• Pressure
• Units of force per area
• Lb/in² or psi
• N/m² or Pa
• Bar, mbar
• Barometer19.2
https://www.thestar.com/autos/2015/1 2/18/w hats-the-prope r-tire-pressure-for-your-car.ht ml
Weather
• Wind is moving air
• Wind direction is the direction from which the wind is coming
• Weather vane
19.2https://www.clipartmax.com/middle/m2 i8A0m2m2d3A 0A0_y ear-five-observ ed-the-s imilarit ies-and-differe nces-car toon-tr ee-with-face/
“Okay, I see where you’re coming from”https://static.vecteezy.com/system/resources/preview s/000/0 92/465 /non_2 x/weat her-vane-vectors.jpg
Weather
•Wind is moving air
•Wind speed (knots)•Anemometer
•Wind is associated with changing weather
•Windchill effect
19.2https://en.wikipedia.org/wiki/Anemometer
Weather
• Precipitation is any form of water that falls to the earth’s surface from the sky
• Rain is most common
• Rain gauge
19.2https://www.duncraft.com/common/ima ges/pr oducts/l arge/S 30012S _zoom.j pg
https://slideplayer.com/slide/12717877/
https://archive.sswm.info/print/1527?ti d=525
Weather
• Humidity is a measure of the amount of invisible water vapor in the air• Absolute humidity (g/m^3)• Relative humidity• Hygrometers• Actually one more thing- listen for the next slide
19.2https://cdn.britannica.com/79/163379-1 38-536 A3C0C/process-water-v apour-atmosphere-video.jpg
AnemometerAn-e-mom-eter
Winds
• Pressure effects
• Pressure gradient
• From higher to lower pressure
19.3
Winds
• Coriolis effect
• Deflects winds
• Deflection depends on hemisphere and speed
19.3
Winds
• Friction effects
• Friction force
• Drag
• Opposite of the direction wind blows
• Related to wind speed
19.3
Winds
• Cyclones and anticyclones
• Surface winds
• Pressure gradient, Coriolis effect, and friction all affect the wind direction and speed
19.3
Winds
• Cyclones and anticyclones
• Cyclonic wind pattern
• Anticyclonic wind pattern
• Many other factors also affect surface winds
19.3
Winds
• Global winds
• Trade winds
• Near 30° latitudes
• Prevailing westerlies
• Polar easterlies
• Cold, dry
19.4
Winds
• Permanent highs, lows
• Doldrums
• Horse latitudes
• Subpolar lows
• Polar highs
19.4
Winds
• Local winds
• Causes
• Sea and land breezes
• Valley and mountain breezes
• Chinooks and foehns
19.5
19C
Clouds
Clouds
• Humidity
• Warmer air can hold more water vapor than cooler air
• Dew point
• Condensation
19.6
Clouds
• A cloud is a mass of extremely tiny liquid water droplets or ice crystals in the air
• Two methods of formation
19.6
Clouds
• Air must absorb enough water vapor to condense water droplets (or ice crystals) at its existing temperature
19.6
Clouds
• Air must cool to the dew point for the amount of water vapor it is holding to condense or form ice crystals
19.6
Clouds
• Air can cool simply by rising
• Condensation nuclei
• Freezing nuclei
19.6
Clouds
• Supercooled clouds
• Liquid water at temperatures below the freezing point of water
• Atmosphere must be quiet
19.6
Clouds
• Types of clouds
• Shapes
• Stratus
• Cumulus
• Cirrus
19.7
Clouds
• Types of clouds
• Altitude zones
• Strato-
• Alto-
• Cirro-
• Cumulo-
19.7
Clouds
• Types of clouds
• Fog is a stratus-like cloud that forms at ground level
• Nimbus
19.7
Clouds
• Precipitation
• Cloud water droplets are very small (about 0.02 mm)
• Coalescence
• Rain
• Drizzle19.8
Clouds
• Precipitation
• Freezing rain
• Sleet
• Updrafts
• Hail
• Snow
• Wintry mix19.8
Clouds
• Dew forms on objects that are cooler than the surrounding air
• Heavier dew forms when air is calm
19.9
Clouds
• Colder air cannot hold as much moisture as warmer air
• Frost
19.9
