Download Weather and Climate

Weather and Climate;
Temperature and Heat
Earth and Space Science
Weather
• The state of the atmosphere
at a given time and place.
The 11 Weather Variables
• Air temperature: degrees Fahrenheit
or Celsius.
• Dewpoint temperature: degrees
Fahrenheit or Celsius. The closer this
temperature is to the actual air
temperature the less dry the air feels.
• Relative humidity: a % between 0
and 100.
The 11 Weather Variables
• Cloudiness: partly cloudy, mostly
cloudy, overcast, broken, scattered,
etc.
• Precipitation: Rain, snow, sleet, hail,
freezing rain, showers, drizzle, ice
pellets, etc. Measured in inches. 10
inches of snow usually melts down to
1 inch of liquid.
More on the 11 Variables
•Air Pressure: Usually measured in
millibars (mb). Average pressure = 1013.2
mb. Low pressures ~ 950 mb to 1005mb.
High pressures ~ 1015mb to 1040 mb.
Under a low pressure area, air is rising and
as a result, the surface has less air
molecules than before. Under a high
pressure area, air is sinking towards the
surface and piles up before spreading out.
More on the 11 Variables
•Wind speed: Created due to a difference
in air pressure. Usually measured in miles
per hour. Most wind speeds range from
calm to 20 mph. Windiest in between a
high and low.
•Visibility: how far you can see. Ranges
between 0 and 10 miles. Less in fog and on
days when there is precipitation. More on
days when you can see the Sun.
More on the 11 Variables
• Wind direction: The direction the wind
is coming from. This can be N, S, E, W,
NE, NW, SE, SW, ENE, SSW, NNW,
NNE, etc.
• Wind chill: A combination of air
temperature and winds speed in order to
show what the temperature feels like.
More on the 11 Variables
• UV index: an index that ranges
from 0 to 10. 10 means your skin
may burn very fast due to
ultraviolet radiation from the Sun.
0 indicates a low risk of sunburn.
The 11 Weather Variables
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Air temperature
Dewpoint temperature
Relative humidity
Cloudiness
Precipitation
Visibility
Air pressure
Wind speed
Wind direction
Wind chill
UV index
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Abington JR HI Weather
• http://www.instaweather.com/WCAU/defau
lt.asp?cid=90&id=ABGTN&obs=full
Climate
• Weather conditions at some
locality averaged over a specified
period of time. (example: the
average high temperature for July
is 78 degrees Fahrenheit.)
Climate
• Departures from long term
averages. (example: over the past
year we are 4.3 inches above normal
for our precipitation.)
• Weather extremes. (the lowest
temperature ever recorded in the
state of Pennsylvania is -42 degrees
Fahrenheit.)
Temperature and Heat
Hey….what is the difference
between temperature and heat?
Temperature and Heat
• Heat: the amount of
kinetic energy in a
system. Energy in the
atmosphere moves in 3
ways. Radiation (from
the Sun to Earth),
conduction (by touching
something), and
convection (air masses
moving around such as
opening a window in the
winter and making your
house cooler.)
• Temperature:
measurement of the
average kinetic energy
(molecules in motion)in a
system. Measured in
degrees.
Did You Know…
• There is no such thing as cold, only an
absence of heat.
• There is no such things as darkness,
only an absence of light.
• There is no such thing as evil, only an
absence of good.