Download Weather and Climate

 Weather
– condition of the bottom layer
of the Earth’s atmosphere in one place
over a short period of time.
 Climate-
a description of the weather
patterns that an area or region typically
experiences over a long period of time.
 The
atmosphere reflects much of the
sun’s radiation.
• It lets in just enough to support life
• traps the heat so that it can’t leave too quickly.
 What
would the result be if we had no
atmosphere? What if we had too much?
 The
placement of the Earth in orbit
around the sun determines when summer
comes to different regions
 Does NOT hit different hemispheres
equally.
• Revolution takes 365 ¼ days
• Earth is tilted on its axis (invisible line from pole
to pole) 23 ½ degrees
 The
sun strikes different parts of the
planet more directly at certain times of
the year.
• North Pole tilted toward the sun- Northern
Hemisphere experiences summer
• Solstices- the days where the sun, at noon,
appears to be directly overhead
 Summer Solstice- overhead at Tropic of Cancer
 Winter Solstice- overhead at Tropic of Capricorn
 Other
markers for seasonal change are
the Equinoxes
• Spring/Fall Equinoxes- the sun appears to be
directly overhead to people at the equator.
(around March 21/September 23)
 Sun’s
rays always fall most directly at the
equator, and the farther from the equator
we get, the colder it gets.
 Latitude divides the world into zones
• Tropical Zones – 23 ½ degrees north and south
(Cancer to Capricorn). Hot year-round.
• Temperate Zones-23 ½ to 66 ½ degrees north
and south. Wider range of temperatures.
• Polar Zones-66 ½ degrees north and south to the
poles. Very cold.
 Sun’s
heat doesn’t all stay in one place
(the equator would be boiling if it did)
• Warm air/liquid are lighter and so tend to rise
while cooler air/liquids sink. This is called
Convection.
• Warm air movements (winds) and warm water
movements (currents) flow from poles to the
equator. Cool winds/currents flow the other way.
 If
the Earth stood still, this would all
happen in a straight line. Because of
rotation, winds and currents bendCoriolis Effect.
• N. Hemisphere – winds curve to right
• S. Hemisphere –winds curve to left
 Different
in each zone
• Equator-light, warm air creates
Doldrums (“slow,” “dull”)
• 30 degrees north or south-more light,
unpredictable winds – the Horse Latitudes
• Between the two are the Trade Windsdependable winds that are useful for sailors