Download Chapter 12 - Mitchell Community Schools

Chapter 12
Meteorology
Meteorology = the study of meteors?
• Meteoros = anything high in the air
• Meteorologists study:
– Hydrometeors: rain, snow, sleet, hail
– Lithometeors: dust, smoke, haze,
particles
– Electrometeors: lightning, thunder
• Weather (short term) vs. climate
(long term)
Imbalanced heating
• What makes summer
warmer than winter?
• Number of hours of
daylight and angle of
the sun’s rays
Air masses
• Movement of air and
water distribute heat
around the earth
• Air masses take on the
properties of their
source regions.
–
–
–
–
–
Polar = cold
Tropical = warm
Maritime = humid
Continental = dry
Arctic: very cold/dry
Coriolis Effect
• Moving air curves
clockwise in the Northern
Hemisphere and
counterclockwise in the
Southern Hemisphere
• Creates global wind
systems:
– Polar easterlies
– Westerlies
– Trade winds
– Horse latitudes
– Equatorial low (ITCZ)
Jet Streams
• Narrow bands of fast
westerly wind
• Position varies
seasonally
• Polar and subtropical
• Storms form along jet
stream paths
Weather Fronts
Stationary front
Pressure Systems
• In a low pressure
system, air rises,
cools and forms
clouds
• Air sinks in a high
pressure system,
usually associated
with fair weather
Weather Observation Systems
• Automated surface observing system
• Radiosonde (upper atmosphere weather
balloon)
• Weather radar (including doppler)
• Weather satellites (infrared, visible and watervapor imagery)
Weather Data
• Temperature
(thermometer)
• Air pressure (barometer)
• Wind speed
(anemometer)
• Relative humidity
(hygrometer)
Weather Station Models
• A station model is a
record of weather data
for a specific place at a
specific time
• Uniform way of
communicating
weather data
• Lots of information in a
small space
Map with weather stations
Same map with Isotherms
Same map with Isobars
Short and Long Term Forecasts
Short-term
• More detailed and accurate
• Hourly forecast based on
present weather
• One- to three-day forecasts
based on larger systems
such as low pressure
systems
Long-term
• Less reliable because of
great number of variables
involved
• Based on large scale
circulation patterns and
weather cycles