Objectives:

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Objectives

• Review concepts covered in class last time.
• Notes on the atmosphere weather.

Warm Ups
1. Why does air move? 2. Explain why does the
wind move in specific belts. 3. What is the
Coriolis effect?
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Objectives
Complete circulation drawings.
Warm Up

• Why does the wind blow?
• Explain the Coriolis effect.

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Objectives
Outline the layers of the atmosphere. Mini
animations on adiabatic vs. latent temperature
changes. Discuss the reason for the seasons if
time.
Warm Up

• A westward blowing wind is called a/an _____ due
  to the direction ________.
• Convention currents in the atmosphere are driven
  by _____________.

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ATMOSPHERE, WEATHER CLIMATE
The atmosphere is a great weather machine in
which a ceaseless flow of energy from the sun
causes global cycling of air water creates
our climate and distributes energy material
through the environment.
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Layers of the AtmoshpereThe atmosphere is
divided into five main layers plus the
ionosphere. It extends over 430 miles (700 km)
into the sky.
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• ADIABATIC HEATING COOLING
• In  an  adiabatic  process  an  increase  in
  temperature is due only to COMPRESSION when the
  air sinks or subsides. A decrease in temperature i
  s due only to EXPANSION when air rises, as with co
  nvective currents   or   air   going   over   moun
  tains.   There   is   no addition or subtraction o
  f heat involved. The changes in
  temperature  are  due  to  the  conversion  of  en
  ergy  from one form to another.
• Environmental Lapse Rate (ELR)
• This is the actual measured decrease in
  temperature with height above the ground ( i.e.
  the rate which is actually occurring, not a
  theoretical rate). Generally this is about 6.5 C
  per 1000 m. This rate does vary and depends on
  local air conditions. There are several
  influencing factors
• Height Lapse rates depend on ground temperature
  (and are normally less near the ground)
• Time of Year Lapse rates are lower in winter or
  during a rainy season.
• Surface Lapse rates are lower over land than
  sea.
• Air masses Different properties of air masses
  mean different lapse rates.

latent temperature changes
adiabatic temperature changes
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Objectives
Commercial airlines fly in the Troposphere
between 20,000 and 50,000. Weather fronts
storm formation. Demonstration The reason for
the seasons. Short video if time.
Warm Up

• Name the two main gasses that make up the
  atmosphere their s.
• Most of the ultraviolet radiation is absorbed by
  _______ in the _______ layer of the atmosphere.
• Rising, expanding air masses cause areas of
  _____ pressure.
• Define ambient air.

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Differential heating of the Earth
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Monsoon Seasonal shifting of wind directions The
large Eurasian (Europe and Asia) land mass and
the equally large Indian Ocean result in
differences between the heating capacities of the
Eurasian landmass and the Indian Ocean. Because
land heats up faster and cools down quicker than
water, a seasonal reversal of winds occur. This
is called the monsoon from an Arabic word Mqusim
which describes a seasonal reversal of winds.
Southwesterly winds blow on shore in South Asia
during the Northern Hemisphere summer while
northeasterly winds blow offshore during the
Northern Hemisphere's winter.
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As the cold air forces the warm air to rise, the
warm air cools and cumulonimbus clouds are
formed. Heavy precipitation and gusty winds
result. The belt of stormy weather is 10 to 50
miles in width. Cold fronts move from 20 to 35
miles per hour. A complete change in weather
occurs within a few hours. A wind shift from a
southerly to a northerly direction and a rapid
rise in pressure occur as the front passes.
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When a cold and warm front merge into one front,
it is known as an occluded front, or occlusion.
The warm air mass becomes strapped between two
colder air masses, one from the west and one from
the east, and is forced aloft. Occluded means
"closed in." A broad belt of bad weather
accompanies the occluded front. Warm front
weather will be followed by cold front weather in
all occlusions.
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Warm frontal clouds map appear 500-600 miles in
advance of the point on the ground which marks
the position of the front. The first signs are
thin wisp of cirrus clouds. Cirrostratus and
altostratus then appear. The altostratus
gradually develop into nimbostratus and
precipitation falls. Low stratus clouds, fog and
drizzle frequently accompany a warm front.
Thunderstorms may be found ahead of a warm front
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Hurricane Formation and Decay Hurricanes form
over tropical waters (between 8 and 20
latitude) in areas of high humidity, light winds,
and warm sea surface temperatures (typically
26.5C 80F or greater) to a depth of 50 m.
These conditions usually prevail in the summer
and early fall months of the tropical North
Atlantic and North Pacific Oceans and for this
reason, hurricane "season" in the northern
hemisphere runs from June through November.
Few things in nature can compare to the
destructive force of a hurricane. Called the
greatest storm on Earth, a hurricane is capable
of annihilating coastal areas with sustained
winds of 155 mph or higher and intense areas of
rainfall and a storm surge. In fact, during its
life cycle a hurricane can expend as much energy
as 10,000 nuclear bombs!
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http//ksks.essortment.com/hurricaneformat_rmem.ht
m
Link to hurricane animation
Hurricane formation storm surge.
The National Hurricane Center uses the
Saffir-Simpson damage potential scale to give
officials and the public an idea of what to
expect from an approaching hurricane. The scale
is named after Herbert Saffir, a consulting
engineer in Coral Gables, Fla., and Robert
Simpson, who was director of the National
Hurricane Center from 1967 through 1973. Graphic
showing the hurricane intensity scale Saffir, an
engineer and expert on wind damage who helped
write the Dade County, Fla., building code,
developed the first version of the scale in 1971
for a United Nations report on construction that
could stand up to high winds. It used wind speeds
as a guide to the damage to expect.
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Objectives

• Outline tornado formation.
• Model seasonal changes.
• Milankovitch

Warm Ups

• Climate is a description of _____ weather
  conditions.
• As a cold front approaches, warm air is forced to
  ___.
• Narrow bands of violent weather are indicative of
  ___ fronts.
• Hurricanes energy comes from _____.

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The strength or force of a tornado is measured on
the Fujita-Pearson Tornado Scale.  According to
the National Weather Service, F6 is the highest
category of tornado, with winds capable of
261-318 mph. Homes may be lifted from their
foundations and carried considerable distances in
this type of tornado. Six of the top ten killer
tornadoes in the United States were rated
F5.  Oklahoma has had five F5 tornadoes since
1950, the year the National Weather Service
started rating them. While an F5 tornado is
ominous and generally causes the most severe
damage, the other lesser classified tornadoes
should not be dealt with lightly. An F4 is
completely capable of flattening cars and hurling
cattle and an F1 can overturn or push a mobile
home off its foundation. 
Fugita tornado scale
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Tornadoes are produced inside powerful
thunderstorms more than any other. Tornadoes form
where warm, moist air and cold, dry air meet and
begin to create updrafts that develop into
massive rotating cumulonimbus clouds or
supercells. Sometimes a spinning column of air
called a vortex forms within these clouds. When
this vortex becomes visible as a funnel cloud and
reaches the ground, a tornado is created.
Because tornadoes form over land, their energy
must come from other sources. The main source is
the heat released as the invisible moisture in
the air changes into visible cloud droplets in
the updrafts. This type of energy is called
latent heat. It was added to the atmosphere when
energy of the sun was used to evaporate water
from the earth's surface.
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• Describe the 3 elements of the Milankovitch
  theory.
• Tilt from 22 to 25 degrees over a 41,000 years.
  
• Precession of equinoxes Timing of perihelion
  22,000 years.
• Eccentricity changes over 100,000 to 400,000
  years.

Milankovich animation
El Nino La Nina and normal conditions animation
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