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Climate
“Typical” weather in region; the average weather or the regular variations in weather in a region over a period of years
• includes temperature, air pressure, humidity, days of sunshine, etc...
• drastically affected by water & mountains– coastlines have cooler summers and warmer winters– mountains greatly slow down winds and weather
AtmosphereBlanket of air surrounding the earthAir – the mixture of gases, mainly nitrogen
and oxygen, that forms the Earth’s atmosphere
• 78% Nitrogen• 21% Oxygen• 1% Argon• 1% Other stuff : Carbon dioxide,
water vapor, ozone, dust, ash, smoke, etc.
Lower LayersTroposphere – the layer of the atmosphere that is
closest to the earth’s surface, where all weather phenomenon occurs.
8 km thick at the poles16 km thick at the equator;
(air temperature normally decreases with height)Stratosphere - upper layer of air 8 - 16 km to
about 50 km and top of the stratosphere contains the ozone layer; almost completely free of clouds.
Middle and Upper layers
Mesosphere – the layer of air, 50km to 80km where temperature begins to decrease with height, mainly because ozone in the stratosphere absorbs energy from the sun, principally ultraviolet radiation
Thermosphere - where air temperatures can exceed 1000° C (1800° F), 80km to 9600 km, primarily due to oxygen absorbing the sun’s energetic rays
Upper-Upper layersIonosphere – the region within the
atmosphere containing ionized molecules, layers of ionized air in the atmosphere extending from almost 60 km above the surface of the earth to altitudes of 1000 km and more.
Exosphere - The region beyond the thermosphere, which extends to about 9,600 km, the outer limit of the atmosphere.
Conditions of the Air
Temperature – amount of hotness or coldness relative to something else
•Thermometer – an instrument that measures relative hotness or coldness•Dew Point temperature – The temperature at which air becomes saturated•Temperature scales:
1°C = 1.8°F or 1°F = 5/9 ° C
Heat transfer
• Conduction – the movement of heat from molecule to molecule
• Convection – the movement of heat by warm and cold currents
• Radiation – the release and transfer of energy in wavelengths of heat and light
PressureAir pressure - the downward pressure exerted by
the weight of the overlying atmosphere or the “weight” of the atmosphere per unit AREA.
• Barometer – an instrument used to measure air pressure
Measured in inches of mercury in a column• Or millibars (metric conversion)• Average air pressure at sea level is 1013 millibars
Water in the atmosphereWater Vapor
• Humidity – the amount of water vapor in the air
• Relative humidity – the actual amount of water vapor in the air compared to the greatest amount the air can hold
Water in the atmosphereWater Vapor
• Saturated – to be completely filled with water vapor
• Psychrometer – an instrument to measure relative humidity
• Hygrometer – an instrument used to measure the air’s humidity
Precipitationwater or ice that condenses in the air and falls
to the ground as:• Rain- liquid water that falls to the ground• Snow - ice crystal flakes; water vapor in the
atmosphere that froze into ice crystals and falls to the ground in the form of flakes
• Sleet -partially melted grains of ice• Hail - pellets made of layers of ice and snow• Freezing rain –rain that freezes into ice as it hits
the ground
Evaporation
the process of changing from liquid to gas; molecules in a liquid state GAIN energy to change into a gaseous state
(latent heat energy is the stored in molecules through evaporation)
Evaporation DRIVES the water cycle
Condensation • the process of changing from gas to liquid;
molecules in a gaseous state that LOOSE energy to change into a liquid state.
Clouds
• a visible mass of dense water vapor or ice suspended in the atmosphere; formed by surface heating & convection and/or warm air lifted by rising over mountains
Wind
air moving at a speed fast enough to be noticed; high pressure moves to low pressure
• Weather Vane – an instrument that measures wind direction
• Anemometer – an instrument that measures wind speed
Major Air Masses
• cA – Continental Artic – dry, very cold
• cP – Continental Polar – dry and cold
• cT – Continental Tropical – dry and warm
• mP – Maritime Polar – moist and cold
• mT – Maritime Tropical – moist and warm
Synoptic Map
Station models – group of symbols depicting weather conditions
Isobar – line of equal pressure
a. show locations of High or Low pressures
b. close lines mean strong winds
c. lines far apart mean gentle winds
Water in the atmosphereWater Vapor
• Humidity – the amount of water vapor in the air
• Relative humidity – the actual amount of water vapor in the air compared to the greatest amount the air can hold