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Our Violent
Atmosphere
The Nature of Storms
Lesson 7
Thunderstorms
Think About It…
During which months do
we get the most
damaging thunderstorms
here in the Piedmont?
Focus Question…
How do the major types of
thunderstorms form?
Average Number of Thunderstorm Days
Annually…
Types of Thunderstorms…
Air Mass - Mountain Where… within one air mass over a mountain
Why… warm air rises over a mountain, forming storm clouds!
When… midafternoon
http://web.mst.edu/~rogersda/umrcourses/ge301/press&siever12.3.png
Types of Thunderstorms…
Air Mass - Sea-Breeze Where… coastal areas, esp. tropics/subtropics
Why… temperature differences between land and sea create convection cells and updrafts
When… summer
http://apollo.lsc.vsc.edu/~wintelsw/MET1010LOL/web/notes/chapter11/ts_ingredients4summary.html
Types of Thunderstorms…
Frontal - Cold Where… at the leading edge of a cold front
Why… cold air pushes warm air rapidly up at the steep cold-front boundary
When… anytime a cold front moves in!
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter11/graphics/cf_xsect.jpg
Types of Thunderstorms…
Frontal – Warm Where… at the
leading edge of a warm front
Why… warm air mass slides up over a cold air mass creating clouds
When… if a warm front moves in with enough moisture and instability
http://www.atmoz.org/img/warm-front.png
Thunderstorms in the
Piedmont…
Which types of
thunderstorms do we
experience here in the
Piedmont?
Frontal (warm and
cold)
Local Air Mass (in the
summer)
http://www2.journalnow.com/mgmedia/image/0/354/118602/severe-storms-cause-damage-across-region/
Stages of Development of a
Thunderstorm…
http://chiefio.wordpress.com/2010/12/28/ignore-the-day-at-your-peril/
NSSL – Q&A
Thunderstorms…
The National Severe Storm
Laboratory is in Norman, OK.
http://www.nssl.noaa.gov/primer/tstor
m/tst_detecting.html
Severe Thunderstorms
anvil
Precipitation
Rain Free Base
http://ed101.bu.edu/StudentDoc/Archives/ED101fa06/mattwall/Extreme%20Weather.htm
How Lightning Forms …
http://www.erh.noaa.gov/bgm/preparedness/swaw/ny/images/Light1.gif
Lightning…
1. What is lightning?
A giant spark of static electricity
2. When does a lightning bolt form?
When there is an electrical imbalance between clouds (-) and the ground (+)
2a. What is a stepped leader?
An invisible channel of negatively charged air from a cloud
http://i.imwx.com/web/multimedia/images/blog/stepped_lightning2.jpg
Lightning…
2b. What is return stroke (positive streamer)?
A channel of positively-charged ions from the ground
3. What causes thunder?
Super-heated air expanding and contracting
How hot is lightning?
30,000 degrees Celsius
http://www.srh.noaa.gov/jetstream/lightning/images/lightning8.jpg
http://www.eoearth.org/files/119701_119800/119773/Step5.jpg
Lightning Damage…
The damage that lightning can do…
7500 forest fires/year
300 injuries/ 93 deaths/year
Property damage
Lightning-struck trees on the
Blue Ridge Parkway http://www.sciencephoto.com/images/download_lo_res.html?id=670034119
http://www.barransclass.com/phys1090/circus/JenkinsD/JenkinsD.html
Lightning Q&A and Safety…
http://www.srh.noaa.gov/jetstream/lightn
ing/lightning_faq.htm#10
Lesson 8
Severe Weather
Think About It…
Where is the safest place
to be during a tornado?
Focus Question…
How do tornados form and
how are they classified?
The Fury of the Wind…
1. A downburst is a violent downdraft concentrated in a local area
a. Two types of downbursts are
a. macrobursts (more than 2 ½ miles wide / 130 mph winds / 5 - 20 min)
b. microbursts (2 ½ miles wide / 168 mph winds / less than 10 min).
http://www.srh.noaa.gov/jetstream/tstorms/wind.htm
b. Microbursts are deadlier b/c they are hard to detect and plan for.
Hail…
2. What is hail?
Precipitation in the form of balls or lumps of ice
Floods…(The main cause of
thunderstorm-related deaths)
3. What are 3 conditions that cause floods to occur?
a. Wind currents in the upper atmosphere are weak
so that weather systems move slowly.
b. Abundant moisture over a limited area
c. Rain falls faster than the ground can absorb it.
d. ADD THIS Groundwater levels are high and
water can not infiltrate the ground.
Slide show May 17, 2011… The Flooding Mississippi
River http://www.huffingtonpost.com/2011/05/12/mississippi-river-flooding-photos-
2011_n_861204.html#s279672&title=Mississippi_River_Flooding
Tornadoes (Formation of…)
A. A change in wind direction and speed creates a horizontal rotation.
B. Strong updrafts tilt the rotating air to a vertical position.
C. A tornado forms within the rotating winds.
Tornado Alley - The Midwest! A cP air mass from
Canada meets a mT
air mass from the
Gulf of Mexico
forming a supercell.
A supercell is a
giant, self-sustaining
storm that can
spawn tornados.
Most tornadoes
occur in May.
The Enhanced Fujita
Scale…
This scale is used to classify a tornado
AFTER the tornado has passed by
looking at the damage and effects of
the tornado.
The Enhanced Fujita
Scale…EF0 or EF1
- % of all tornados…
80
- Path…
up to 3 miles
- Wind Speed…
60-115 mph
- Duration…
1 – 10 minutes Dr. Theodore Fujita
The Enhanced Fujita
Scale…EF2 or EF3
- % of all tornados…
19
- Path…
15+ miles
- Wind Speed…
110 - 165 mph
- Duration…
20+ minutes
The Enhanced Fujita
Scale…EF4 or EF5
- % of all tornados…
1 (Thankfully!)
- Path…
50+ miles
- Wind Speed…
200+ mph
- Duration…
1+ hours
Tornado Safety…
1. Move to a pre-designated shelter – to a
basement if possible.
2. Move to an interior room/hall, lowest floor, under
sturdy furniture. (A bath tub is safest!)
3. Stay away from windows.
4. Get out of vehicles!
5. Don’t try to outrun a tornado.
6. If outside, lie flat in a ditch or depression.
7. Abandon a mobile home for a shelter.
Lesson 9
Tropical Storms
Think About It…
From which direction do
the hurricanes which hit
our east coast come?
Focus Question…
How does a hurricane
form?
Tropical Cyclones…
1. A tropical cyclone can be described as a…
Large, rotating, low pressure storm
2. We call these storms…
hurricanes
3. Tropical cyclones derive a tremendous amount of energy from…
Warm, tropical oceans http://www.nhc.noaa.gov/HAW2/english/history.shtml
Tropical Cyclones…
4. Which direction do
tropical cyclones turn in
the northern hemisphere?
Counterclockwise
It is a low
pressure system!
Fran, 1996, Cape Fear, NC
Name was retired!
Tropical Cyclones…
5. As a hurricane strengthens, what do the following components do?
a. Air pressure in eyewall– decreases
b. Surface wind speeds – increase
6. What are two basic conditions that tropical cyclones require to form?
a. Lots of warm ocean water
b. Disturbance to lift the air
Tropical Cyclones…
1) Tropical cyclones in the N. Hemisphere move steadily towards…
the west! 2) Which wind system moves across the USA and usually guides
hurricanes out into the Atlantic Ocean?
the prevailing westerlies
Hurricane Rita – 2005, 3rd lowest pressure in Atlantic (897 mb), hit as cat. 3
Development of a Tropical
Cyclone…
Tropical Disturbance – a weak, low-pressure
system – group of thunderstorms collect
Development of a Tropical
Cyclone…
Tropical Depression – a disturbance begins
to rotate around the center of low pressure
Katrina as a tropical depression
Development of a Tropical
Cyclone…
Tropical Storm – a depression is labeled a
storm when the wind speeds reach 39 mph.
Tropical Storm Dalila, July 2007
Development of a Tropical
Cyclone…
Tropical Hurricane – pressure drops and the
wind speeds reach 74 mph
Ivan
2006
Dean
2007
Katrina
2005
Hurricane History…
http://www.nhc.noaa.gov/HAW2/englis
h/history.shtml#galveston
Anatomy of a Hurricane…
Classifying Hurricanes…
1. What scale is used to classify hurricanes?
Saffir-Simpson
2. What are the four characteristics of a hurricane described by the scale?
a. Wind speed – how high?
b. Air pressure – how low?
c. Potential for damage – how much?!
d. Storm surge
Weds. 12/12/12…
2:10 pm
OVC
St
46 degrees
30.26
54%
0
No fronts!
Classifying Hurricanes…
3. The Saffir-Simpson Scale…
a. Categories 1 – 5
b. Category that does the most damage – 5
c. Wind speed of a cat 5? > 155 mph
d. Three most powerful storms to hit USA?
a. Florida Keys, 1935
b. Camille, 1969
c. Andrew, 1992
Classifying Hurricanes…
4. A hurricane runs
out of energy
a. When it
moves over
land
b. When it
moves over
cold water
Hurricane Hazards…
1. The strongest
winds in a
hurricane are in
the…
… eye wall
Hurricane Hazards…
2. What is a storm surge?
1. When hurricane force winds drive a mound
of ocean water towards coastal areas
Hurricane Hazards…
3. What hurricane hazard is caused by great
amounts of rain?
floods
Flooding from
Hurricane Fran
Hurricane Hazards…
5. Which agency is
responsible for
tracking and
forecasting
hurricanes?
The National
Hurricane Center
in Miami, FL at
the FIU Campus
(NOAA)
The World’s Best Hurricane
Safety Tip…
EVACUATE!!
Lesson 10
Human Impact on Air Quality
Smog…
1. Smog is a yellow-brown photochemical haze.
2. Smog is caused by the action of solar
radiation on an atmosphere polluted with
hydrocarbons and nitrogen oxides, mostly
from car exhaust.
3. Smog can make it difficult to breathe!
4. The major chemical in smog is ozone.
5. Ozone irritates the eyes, nose, throat, and
lungs.
Particulate Matter…
1. Four examples of particulate matter include…
1. ash, dust, pollen, and asbestos fibers.
2. These are forms of SOLID pollutants in the air.
2. Particulate matter is harmful to people
because they can…
1. lodge in lung tissues,
2. disrupt normal functions,
3. cause breathing difficulties and lung disease.
Global Warming…
a. Global warming is…
1. an increase in Earth’s average surface
temperature.
b. Some scientists believe that the cause of
global warming is...
1. … the burning of fossil fuels
2. …which releases carbon dioxide (CO2)
Remember - CO2 makes up only .04% of the
atmosphere! (4 out of 10,000 molecules)
There are many scientists who believe the Sun
has the major role in global warming/cooling.
The Greenhouse Effect
What is the greenhouse effect? It is heat from the sun being trapped by the gases in our atmosphere. A greenhouse effect you may relate
to is that of a closed car on a cold, sunny day in winter.
The greenhouse effect is a GOOD thing! It allows for life on our planet!
The Greenhouse Effect
The Greenhouse Effect and
Carbon Dioxide
Carbon dioxide is released into the atmosphere by respiration,
decay, and burning of fossil fuels. It is absorbed or stored by
such carbon sinks as untapped fossil fuels, oceans, and forests.
The Ozone Issue
The ozone layer is found in the stratosphere.
It absorbs ultraviolet radiation from the sun.
The Ozone Issue
The ozone layer is important because…
• Ultraviolet radiation from the sun can cause cataracts (a clouding of the lens of the eye) and skin cancer.
• Ultraviolet radiation can kill the eggs of certain animals like amphibians because they lay their eggs in shallow water.
The Ozone Issue
The chemical formula for
ozone is O3
The Ozone Issue
Man-made chemicals called (CFCs) chlorofluorocarbons react with ozone and break it apart.
The part of the CFC molecule that reacts with the ozone molecule is the chlorine atom.
The Ozone Issue
CFCs are used as refrigerants, coolants, propellants in aerosol cans, and Styrofoam.
The Ozone Issue
This diagram illustrates what a “hole” in the ozone might look like.
The Ozone Issue
“The hole in the ozone layer above Antarctica is seen in a series of satellite images over a 21-year time span.
The hole may actually close within 50 years as the level of destructive ozone-depleting CFCs in the atmosphere is now declining, one of the world's leading atmospheric scientist Paul Fraser from the Australian government's Commonwealth Scientific and Industrial Research Organisation (CSIRO) said on Tuesday.
Fraser said he had measured a decline in ozone-destroying gases since 2000. — Reuters photo”
The Ozone Issue
d. CFCs were banned in the late 1980’s in industrialized nations. They are still in use in some places in the world.
“Under the 1987 Montreal Protocol, developing countries committed themselves to halving consumption and production of the CFCs by 2005 and to achieving an 85 percent cut by 2007.”
Acid Rain…
a. Acid Rain is precipitation with a pH of less than 5.
b. The pH of natural precipitation is 5.0 to 5.6.
c. Acid precipitation forms when sulfur dioxide and nitrogen oxides combine with atmospheric moisture to create sulfuric acid and nitric acid.
d. Six types of acid precipitation are acidic rain, snow, fog, mist, gas, and dust.
e. Nitrous oxide and sulfur dioxide come from volcanoes, marshes, and human activities
Acid Rain…
f. The source of acid precipitation that receives the most attention is caused by coal-burning power plants in the midwestern USA.
g. Three effects of acid precipitation are...
a. It causes damage to aquatic ecosystems and vegetation.
b. It affects plants and soil.
c. It damages stone buildings and statues.
h. Acid precipitation can be prevented by using wet scrubbers to reduce emissions of sulfur dioxide by coal-burning power plants.
World’s Tallest Buddha…
Buddha will get a face
lift after many years of
weathering and acid
rain damage.
