Download Science Scientific Method - SOEST

Lecture 1
Lecture 1
Outline of Today’s Lecture
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What is it that defines science?
What is meteorology?
A brief history of meteorology.
What does the atmosphere do for us?
What is the atmosphere composed of?
Intro to atmospheric structure
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Science
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Scientific Method
1. Start with an educated guess or “hypothesis”
2. The guess should leads to a prediction that can
be tested.
3. Design an experiment to test the hypothesis and
prediction.
4. Evaluate the results of the experiment to verify or
refute hypothesis
5. Construct a theory (or model) based on test
results.
6. Repeat cycle (1-5) to refine/modify the theory.
• What is it that defines science?
• How is science distinguished from
other academic endeavors (e.g, history
or comparative religion)?
• Why is creationism not considered
science by scientists?
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Scientific Method
What is Meteorology?
• Our understanding of the world grows as our theories
become more complete and precise.
• The term meteorology comes from the Greek
word meteoros, meaning, “high in the air.”
• A key to the Scientific Method is that the results of a
good experiment are reproducible. The same
experiment using the same hardware will produce the
same results time after time.
• Rain and snow are hydrometeors.
• Meteorology is the study of the atmosphere
and the processes that produce weather.
• If a hypothesis can not be tested then it falls outside the
current realm of scientific understanding or knowledge,
and is considered “speculation.”
• Meteorology is also called atmospheric
science.
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A Brief History of Meteorology
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A Brief History of Meteorology
Answer: Lack of instruments to make observations.
340 BC In a book he called Meteorologica, the Greek
philosopher Aristotle was the first person to organize and
record his weather thoughts in a systematic way.
~330 BC A student of Aristotle, Theophrates, wrote first book
on weather forecasting.
~200 BC Hero developed crude water thermometer.
~1450 Cardinal Nicholas de Cusa invented hygrometer.
~1590 Galileo invented thermometer.
1643 A student of Galileo, Torricelli, invented the water barometer to
measure atmospheric pressure. Galileo used mercury the next year.
~1650 Pascal and Descartes demonstrated that pressure decreases with
height and a famous experiment in the Alps.
For nearly 2000 Years we have a Big Blank in progress
Why?
1667 Hooke invented swing type anemometer in measure wind speed.
1834 Telegraph invented to transmit observations.
1940’s Weather balloon and weather radars developed
1950’s High Speed Computers invented and applied to weather prediction.
1960 The first weather satellite, Tiros 1, was launched.
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What does the Atmosphere
do for us?
The atmosphere moderates temperatures
near the Earth's surface
• Contains the oxygen that humans require for
breathing.
• Sound requires a medium to travel through.
• Provides for a Hydrological cycle
• Atmospheric "Greenhouse Effect"
– Without the atmosphere, the average surface temperature of
the Earth would be about 0 °F
– Due to "Greenhouse Effect", the average surface
temperature is about 59 °F
• Reduces diurnal temperature swings -- without the
atmosphere, the days would be much hotter and the
nights much colder
– {Evaporation of water from surface} à
{Condensation in clouds} à {Rain or snow}
• Shields the Earth from harmful ultraviolet
radiation
• Atmosphere moderates temperature near
Earth’s surface
– Mercury’s daytime temperature is 700 °F
– Mercury’s nighttime temperature is -300 °F
• Transports energy from the tropics to the poles
otherwise tropics would be much warmer, poles
much colder
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Vertical Structure of Atmosphere
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Thickness of the Atmosphere
• The atmosphere becomes
thinner with height
• There is no easy way to
establish the “top” of the
Earth’s atmosphere
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Thickness of the Atmosphere
The atmosphere is a thin blanket of "air" -- a
mixture of mostly gases and some aerosols.
• Top of a thunderstorm =
~12 km
• 100 km above sea level
- 99.99997 % of the
atmosphere is below
this height
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Gas -- substance in which individual atoms and
molecules are not chemically bound together.
Different from liquids and solids.
Aerosols -- tiny liquid or solid particles that are
suspended in the air, most are too small to be seen
individually
2.
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cloud droplets (liquid)
dust, sea salt, smoke, volcanic ash (solid)
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Permanent Gases* % of total
(excluding water vapor)
Lubbock Aerosols
Nitrogen (N2)
78%
Oxygen (O2)
21%
99%
* This is true for the lowest ~50 miles or 80
kilometers.
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Vertical Structure of the
Atmosphere
Variable Gases
Variable Gases
% of total
Water Vapor (H2O)
0.01% - 4 %
Carbon Dioxide (CO2)
0.036 %
365
(increasing)
Ozone (O3)
0.000004 %
0.04
(troposphere)
0.002%
0.0002
5 – 12 (stratosphere)
Chlorofluorocarbons(CFC)
Layers in the atmosphere
PPM (parts per million)
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–
(most at surface)
Density
Chemical Composition
Electrical Characteristics
Temperature
Aerosols (NOT gas)
0.000001%
Air Pollution -- Elevated levels of aerosols or harmful gases
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Characterizing with Chemical
Composition
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Characterizing with Temperature
• Homosphere - Region within ~80 km of
the Earth’s surface where there is
chemical homogeneity.
• Heterosphere - Located above the
Homosphere where lighter gases
become more dominant with height.
Standard Atmosphere
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–
–
–
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Troposphere (lowest)
Stratosphere
Mesosphere
Thermosphere (highest)
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Characterizing with Temperature
Characterizing with Temperature
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Troposphere
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Tropopause
The warm air of the
stratosphere acts
as a lid on updrafts
in the troposphere.
The stratosphere is
warm because of
absorption of UV
sunlight by ozone.
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Overshooting
Thunderstorm
Characterizing with Electrical
Composition
• Ionosphere
– Layer extends from the upper mesosphere into
the thermosphere.
– It contains large numbers of electrically charged
particles called ions.
• Ions are formed when electrically neutral atoms or
molecules lose one or more electrons and become
positively charged. (solar energy)
Anvil Cloud
– Responsible for the aurora borealis (northern
lights)
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Summary
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