Ch 16 Weather Sec 16 1

1
Ch 16 Weather Sec 16 - 1

• Energy from the sun comes to the Earth as
  electromagnetic waves, through empty space. This
  is a form of radiation.
• The suns energy is either in the form of visible
  light, infrared radiation or ultraviolet
  radiation.
• Infrared is heat energy, ultraviolet can cause
  sunburns, and skin and eye damage.
• Light travels in wavelengths (pg 543)
• The atmosphere absorbs and reflects sunlight, the
  rest passes right through it. When the earths
  surface becomes heated, it radiates most of the
  energy back into the atmosphere as infrared
  radiation.
• Greenhouse Effect is the process of gases holding
  heat in to atmosphere like a greenhouse.

2
Heat Transfer Sec 16-2

• Temperature is the average amount of energy of
  motion of each particle of a substance.
• Thermal energy is the total amount of energy.
• Temperature is measured with a thermometer in
  Celsius(metric units) or Fahrenheit(english)
• Water freezes at 0C and 32F
• Water boils at 100C and 212F
• Heat is transferred 3 ways
• Radiation through empty space
• Conduction direct transfer, touching something
• Convection through fluids(gas-air,
  liquid-water)
• The Troposphere is the first layer of the
  atmosphere and it is heated by these processes
  working together.
• Convection currents are hot air moving up and
  cold air moving down in circular motions.

3
Winds Sec 16 - 3

• Wind is the horizontal movement of air from high
  pressure to low pressure.
• Anemometer measures wind speed and a wind vane
  measures wind direction.
• Wind-chill factor is the increase in cooling
  power of wind on the overall temperature.
• Local Winds blow over short distances like a sea
  breeze or a land breeze. Winds are named from
  where they come from.
• Global winds are steady long blowing winds. The
  Coriolis Effect makes the winds curve like the
  ocean currents. (North right,South left)

4

• Major global winds are divided by latitudes (pg
  557)
• Doldrums are dead winds at the equator.
• Horse Latitudes are also very slow dead winds
  that got their names from early sailors throwing
  horses overboard here.
• Trade Winds are good winds blowing towards the
  equator between the equator and 30 latitude
• Prevailing Westerlies are good winds blowing
  towards the poles between 30 and 60 latitude.
  (important for the weather the US)
• Polar Easterlies run from the poles to 60 as a
  return of cold dry air.
• Jet Streams are fast winds blowing only in
  specific areas. They drive the weather.(Polar,
  Subtropical)

5
Water in the Atmosphere Sec 16 - 4

• The water cycle is the continuous movement of
  water between the atmosphere and the land.
• Humidity is the measure of water vapor in the air
• Relative Humidity is the percentage of vapor.
• Psychrometer is an instrument used to measure
  relative humidity. Uses 2 types of thermometers
  (wet and dry)
• Clouds form when water vapor in the air condenses
  to form liquid water or ice in the air.
• Dew point is the temp where water condenses.

6

• Clouds also has solid particles in it, that is
  why we can see them. The darker the cloud the
  more water vapor is in it, the better the chance
  for precipitation.
• Types of Clouds
• Cirrus High wispy, feathery clouds, usually
  meaning good weather.
• Cumulus Medium height, puffy cotton ball
  clouds, fair weather.
• Stratus flat layers, usually low, covering all
  the sky, typically rainy weather.
• Fog is usually a stratus cloud that forms on the
  ground.

7
Precipitation Sec 16 - 5

• Any form of water falling back down to the Earth
  is called precipitation. Water droplet sizes
  vary depending on where they originate. (Pg 567)
• Common precipitation include
• Rain liquid water, mist, drizzle and showers
• Sleet rain that freezes on the way down
• Freezing Rain rain that freezes when it hits
  something cold on the surface of the earth.
• Snow water vapor that converts directly to a
  crystal, all different in size and shape.
• Hail ice balls that form in the clouds before
  they fall to the Earth. Usually not in the
  winter.
• Cloud seeding can help trigger rain by sprinkling
  crystals of silver iodide and dry ice into a
  cloud.
• Measuring Precipitation can be done with a rain
  gauge.
• 1 cm of rain is equal to 10 cm on snow.