Causes of Weather - Suffolk Public Schools...
Transcript of Causes of Weather - Suffolk Public Schools...
Causes of Weather
Focus Question
How’s the weather today?
VA SOL
SOL 2 (Infused) The student will demonstrate scientific reasoning and logic by– a.analyzing how science explains and predicts the interactions and
dynamics of complex Earth systems; and
SOL 12 The student will investigate and understand the origin and evolution of the atmosphere and the interrelationship of geologic processes, biologic processes, and human activities on its composition and dynamics. Key concepts include:– d. atmospheric regulation mechanisms including the effects of density
differences and energy transfer
The student will investigate and understand that energy transfer between the sun and the Earth and its atmosphere drives weather and climate on Earth. Key concepts include– d. weather phenomena and the factors that affect climate including
radiation and convection
Enduring Understanding
Energy transfer between the Earth’s surface
and the atmosphere creates the weather.
The atmosphere remains in balance until
acted on by an outside force.
Causes of Weather
As mentioned before the various atmospheric
processes we call weather are caused by
the ongoing balancing and vital
redistribution of Earth’s heat energy
throughout the planet
Weather
– Weather is the current state and short
term variations in the state of the
atmosphere
Takes place over minutes, hours, days,
weeks, months
Causes of Weather
Climate is the long term variations for a
particular area
– Averaged over 30 years or more of weather
data
Striking Angle
Since the Earth is tilted and spherical in
shape the Sun’s energy strikes our surface
unevenly. The lower angle receives less
energy
Striking Angle
The area between the tropics receives more
direct sunlight
The area near the poles receives sunlight at
a lower angle and the energy is spread
over a larger area
Striking Angle
Coriolis Effect
Redistribution of Wealth
Without the atmosphere this energy
imbalance would continue and the tropics
would be very hot and the poles very cold
year round
– The oceans store the majority of heat at
Earth’s surface
Redistribution of Wealth
Temperature differences in the air result in
differences in density which the cause
upward and downward movement
The convection currents of the
atmosphere redistribute the heat energy as
air over the warmer regions rises, cools,
then descends over cooler regions.
Redistribution of Wealth
This movement causes
weather
Redistribution of Wealth
Energy moves from source to sink:
high to low
Redistribution of Wealth
Air Masses
An air mass is a large body of air that takes
on the characteristics of the body over which
it forms. They can form over either land or
water and are classified according to their
source regions
Air Masses
Continental Tropical (cT) air masses contain warm, dry air that forms over warm areas of land
Maritime Tropical (mT) air masses contain warm, humid air that forms over warm areas of the ocean
Continental Polar (cP) air masses contain cold, dry air that forms over cold areas of land
Maritime Polar (mP) air masses contain cold, humid air that forms over cold areas of the ocean
Arctic (A) air masses are basically the same as cP, but much colder and are associated with extreme cold
North American Source Regions
All five main air mass types can be found in
North America because of our close
proximity to the source regions associated
with each type of air mass
North American Source Regions
Continental Tropical (cT) air forms over the
desert of the southwest United States and
Mexico
North American Source Regions
Maritime Tropical (mT) air forms over the
southern Atlantic, Gulf of Mexico, and
southern Pacific oceans
North American Source Regions
Continental Polar (cP) air forms over the
interior of Canada and Alaska
North American Source Regions
Maritime Polar (mP) air forms in the
northern Pacific and Atlantic oceans
North American Source Regions
Arctic (A) air develops over the extreme
northern regions of the continent
Stability and Air Mass Movement
Air masses do not stay in one place
indefinitely. They move and transfer their
heat from one area to another establishing a
balance of heat throughout the planet
Stability and Air Mass Movement
Air mass modification occurs when the
moving air mass changes to become more
like the surface over which it travels
Heat and moisture are exchanged with the
surface as the air mass travels over it
Stability and Air Mass Movement
Eventually the air mass will become
modified to the point it is indistinguishable
from the new surface over which it is
traveling and simply becomes part of the air
over the new source region