Transcript weathernotes

Weather
Chapter 1: Section 1
The Atmosphere
Weather is the condition of Earth’s
atmosphere at a particular place and time.
Atmosphere: layer of gases that surrounds
the planet.
78% nitrogen
21% oxygen
1% other gases(CO2, argon)
Air pressure: the force of a column of air
pushing down on an area.
*measured with a barometer
*decreases as altitude increases
Low pressure = rainy, cloudy
High pressure = clear skies
Air has mass, density, and pressure.
Warm air = less dense
Cool air = more dense
Measuring Air Pressure
Barometers
– Mercury barometer
• (inches of mercury)
– Aneroid barometer
• (millibars)
1013.2 mb =
29.92
________
inches
1022.8 mb =
30.20
________
inches
30.53 inches =
1034.0
________
mb
29.81 inches =
1009.5
________
mb
Air Pressure
Layers of the Atmosphere
Section 4
Four layers based on changes in temperature.
Troposphere: lowest layer where weather
occurs.
WHY? *The only layer containing water*
Stratosphere: has the ozone (O3) layer.
Mesosphere: coldest layer.
Thermosphere: outer layer and is very hot.
Earth’s Atmosphere
Weather Factors
Chapter 2
1. Energy: travels from the Sun to Earth by
electromagnetic waves in the form of light,
infrared radiation(heat), and ultraviolet
radiation.
Energy is absorbed, reflected, and scattered
by the atmosphere.
A Green house
Greenhouse Effect: is when heat is trapped
by the gases in the atmosphere.
CO2 – burning fossil fuels increases amount.
2. Heat: moves throughout the atmosphere
by conduction, convection, and radiation
affecting weather.
3. Wind: is a horizontal movement of air from
high pressure to low pressure. Named by
where they come from.
Anemometer: measures wind speed.
Wind-chill factor: increased cooling caused
by wind.
Local Winds: caused by unequal heating of
Earth’s surface within a small area.
Examples:
Sea breeze
Land Breeze
Global Winds: caused by movement of air
between the equator and poles.
4. Water:
Water Cycle: is the movement of water
between the atmosphere and Earth’s surface.
*causes= humidity, clouds, and precipitation.
Humidity: amount of water vapor in the air.
Relative Humidity: % of vapor in the air
compared to the maximum amount the air can
hold at that temperature.
*Measured with a psychrometer
Clouds: form when water condenses in the
atmosphere when it cools.
Examples:
Cumulonimbus
Cirrus
Stratus
Cumulus
Precipitation: any form of water that falls
from the sky.
Examples: Rain, sleet, snow, hail
*measured with a rain gauge
*Acid rain: man made form of pollution
*Natural pollutant: Pollen, volcanic ash
Mountain Weather
Weather w.s. # 6
Weather Patterns
Chapter 3
Air Masses and Fronts:
Air masses are classified based on
their temperature and humidity.
Temperature: hot/cold
Humidity: moist/dry
Tropical – warm = (T)
Polar – cold = (P)
Maritime – moist = (m)
Continental – dry = (c)
moist & ________
cold
Ex: mP air is ______
Fronts: Areas where air masses meet
and do NOT mix.
1. Cold - violent weather at the front.
2. Warm - rain ahead of front.
3. Stationary – neither air mass is strong
enough to move the other.
4. Occluded – warm air trapped above
and between two cold air masses.
For all fronts, the direction of symbols
tells you direction front is moving
southeast
northeast
Quiz Time…
A
What type of front is at A?
cold
Storms
Storms: are a violent disturbance in
Earth’s atmosphere.
Thunderstorms: from cumulonimbus clouds.
Tornadoes: are fast moving funnel shaped
clouds.
Hurricanes: are large tropical storms
forming over warm water
Isobars: show areas of equal air pressure.
What is the barometric pressure at Z?
1012mb
Z
Lake Effect Snow