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Where are they? Why is there no weather?
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Meteorology The study of weather
Good sites for weather info: weather.com nws
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Describe the weather outside right now
The variables measured are: Temperature Humidity (Dew point and RH) Pressure (High /Low) Wind (speed and direction) Precipitation (rain, sleet, snow, etc) Cloud (percentage and type) Will these variable change over the next minute? Hour?day?week?
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Air Temp Instrument: Thermometer
Temp decreases as you increase in altitude
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What affects our temperature?
Latitude (East Rockaway vs Miami) Altitude (ER vs Mt Marcy) Closeness to Ocean (ER vs Elmira) Cloud cover (Clear vs cloudy) Land use
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Humidity Absolute Humidity – amount of water vapor in the air
Relative Humidity (RH) – amount of water vapor in the air vs the amount it can hold at a specific temp. Dew Point (DP) – the temp to which air has to cool for dew to form What is the relationship between DP and RH? Instrument: Sling psychrometer
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DP and RH Dew Point Relative Humidity
The closer the DP temp is the air temp more likely clouds/dew/precip will form. How does this relate to RH? Relative Humidity Written as a percent. The closer to 100%, the more likely clouds and precip.
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Sling Psychrometer Dry Bulb – AirTemp Wet Bulb - fabric
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Dry Bulb Wet Bulb Wet Bulb Depress. Relative Humidity Dew Point Temp 1 12C 7°C 2 22°C 20°C 3 18°C 12°C 4 6°C 5°C 5 21°C 6 16°C 66% 7 19°C 8 17°C 13°C 63% 10°C 9 86 F 77 F 10 64 F 54 F
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11 26°C 24°C 12 16°C 12°C 13 30°C 21°C 14 0°C -2°C 15 25°C 16 11°C 6°C 17 15°C 18 8°C 4°C 19 1°C 14°C 20 -1°C
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Barometric Pressure Force or weight of air pushing on the surface of earth Pressure decreases as altitude increases (why) Moist air light (Low) Dry air heavy (High) Instrument: barometer
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Barometric Pressure
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Pressure Air flows from High to Low causing wind! H L High (H)
Dry conditions Air circulates clockwise and outward Air is sink from above Low (L) Wet Condition (Precipitation) Air circulates counterclockwise and inward nws-goes sat Air flows from High to Low causing wind! H L
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http://www. newmediastudio
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Wind Horizontal movement of air.
Caused by difference in heating of Earth (difference in air pressure [H to L]) Sun heats Earth, Earth heats atmosphere (conduction, convection, radiation) Instrument: Anemometer, Wind vane
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Insolation and re-radiation
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Local vs Planetary Winds
examples Land and Sea Breezes Mountain Ranges Planetary Move weather systems P.14 esrt
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Land and Sea Breeze
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Mountain Ranges
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Precipitation and Clouds
Clouds form when rising air reaches the dew point temperature and there are condensation nuclei (particles of dust, pollen, ash, etc) present. Precipitation occurs when the air is saturated and water vapor becomes either a solid or a liquid. What is condensation? What are other phase changes? When is energy released? Absorbed?
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This method of cloud classification was proposed by Luke Howard (1803) who named the clouds based on their form: Cirrus - curl Stratus - layer Cumulus - heap Nimbus - rain and on their height: High Middle Low Contrails fall into the category of cirrus as they are high level clouds that consist entirely of ice crystals
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Units millibars, inches, atmospheres
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