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Meteorology Basics Lecture Science 2201 (chapter 18). “Climate is what you expect, weather is what you get.”. Distinguish between…. Weather Seasons Climate. Chemical Composition of the Atmosphere. Nitrogen 78% Oxygen 21% Argon 0.9% Carbon Dioxide 0.03% Trace substances
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Meteorology Basics LectureScience 2201 (chapter 18) “Climate is what you expect, weather is what you get.”
Distinguish between… • Weather • Seasons • Climate
Chemical Composition of the Atmosphere • Nitrogen 78% • Oxygen 21% • Argon 0.9% • Carbon Dioxide 0.03% • Trace substances • Water Vapor
5 variables influence the atmosphere: • Temperature • Pressure • Humidity • Cloudiness • Winds
Variables influencing the atmosphere… temperature: • Measure of heat • Average kinetic energy of molecules • Weather reports give air temperature at ground level
High Pressure Region where air has piled up Warmer and dryer than surrounding air Low Pressure Region where air has stretched out Tends to rise and cool, vapor condenses into clouds Variables influencing the atmosphere… pressure:
Variables influencing the atmosphere… humidity: • “relative humidity” – the ratio of amount of water vapor in air at current temp to max amount vapor air can hold at that temp
Variables influencing the atmosphere… cloudiness: • Water droplets • Ice crystals • Warm air rises, cools and condenses (phase change)
Variables influencing the atmosphere… winds: • Due to differential heating of the earth’s surface • Warm air rises • Cooler air flows in
Why is it warmer near the Earth’s equator and colder near the poles?What patterns of global air flow occur? Check your neighbor. Make a sketch to explain your answer.
Where does your weather forecast come from? • National Weather Service • World Weather Building in Camp Springs, Maryland • Media weather specialists
Weather Forecasting • Wrong half the time? • Many features, all are changeable • Nowcast Forecast • CNN Weather link
The Instruments • Thermometer • Hygrometer • Barometer • Weathervane • Anemometer
The Instrument Carriers • 10,000 land-based & 7,000 ocean-based • Weather Balloons (1,000 released 2X/day) • Buoys (300 drift or are moored at sea) • Automated Weather Stations (about 1,000) • Doppler Radar • Satellites
Reading a Weather Map • Pressure Centers • Fronts • Precipitation • Temp. Readings • Surface Winds
Winter Air Masses • Continental Polar • Maritime Polar • Maritime Tropical
Summer Air Masses • Continental Polar • Maritime Tropical • Continental Tropical
Cold Front digs in underneath a warm air mass Warm air rises, mixes with colder air, & condenses into clouds “Fronts” = a clash of air masses
Warm Front rides up above the cold air In the rising warm air, clouds form far ahead of advancing warm front “Fronts” = a clash of air masses
Air Masses Doing Battle link Cloud Classification link