Climate and Global Change Notes 3-1 Observing ClimaHow do we measure climaparamers? • Surface Measurements - Temperature > Wind Chill Temperature Index > Heat Index - Pressure - Density - Water Vapor > Gas Laws - Wind - Clouds - Water - Precipitation • Upper-air Measurements - Temperature, Pressure (Height), Water Vapor, Wind • Remote Sensing Measurements Observing - “To see a world in a grain of sand, And a heaven in a wild flower, Hold infinity in the palm of your hand, And eternity in an hour.” Auguries of Innocence by William Blake
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3-1 Observing Clima - USRA's Science and Technology …sti.usra.edu/TRESTE/teaching_resources/faculty_teaching...• Fahrenheit to Celsius C = 5/9 ( F - 32 ) • Celsius to Kelvin
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Climate and Global Change Notes
3-1
Observing ClimateHow do we measure climate parameters?• Surface Measurements
- Temperature> Wind Chill Temperature Index> Heat Index
- Pressure
- Density - Water Vapor> Gas Laws
- Wind - Clouds
- Water - Precipitation
• Upper-air Measurements
- Temperature, Pressure (Height), Water Vapor, Wind
• Remote Sensing Measurements
Observing -
“To see a world in a grain of sand,And a heaven in a wild flower,Hold infinity in the palm of your hand,And eternity in an hour.”
Auguries of Innocenceby William Blake
Climate and Global Change Notes
3-2
Observing Climate - SurfaceTemperature
Instrument DesignThermometers
Maximum TemperatureMinimum TemperatureThermograph
Exposure
Temperature ScalesWindchillHeat Index
Science Concepts
DefinitionKinetic Energy - Molecular
Boiling Point Versus AltitudeExpansionSurface Tension
VentilationRadiational HeatingEvaporational CoolingTemperature Versus Height
Effect of WindEffect of Humidity
The Earth System (Kump, Kastin & Crane)• Chap. 3 (pp. 38-39)
Climate and Global Change Notes
3-3
Observing Climate - Temperature
Why do we need thermometers?
Are we very good thermometers?
What steps do we need to perform to “build” a thermometer?
Climate and Global Change Notes
3-4
Observing Climate - TemperatureIs there a problem here? Why do fevers give you the
chills?
When you have an infection,your body resets your internalthermostat above the normal98.6°F, say to 101°, 102° ormaybe 103°F. You then feelcold and shiver attempting toraise your body temperature tothe new reset elevated level.
When your fever breaks, yourbody sets your thermostatback to 98.6°F. That's whenyou start to sweat, throw offthe covers.
the average molecular kineticenergy of a substance
• As the temperature of mostsubstances is increased, thesubstance expands
Thermometer• Galileo Galilei (1564-1642)
invented a thermoscope in1593
• Galileo thermometer -Galileo discovered that liquid’s density changes with temperature.Thus, fluid’s buoyancy changes with temperature. Lowest floatingsphere indicates room temperature.
• Italian Francesco Sagredo, a contemporary of Galileo’s, divided thetemperature scale into 360 divisions similar to the divisions in a circle;thus, the name degrees
Observing Climate - Temperature
http://galileo.imss.firenze.it/museo/4/eiv07.html
“Took a sip of Pepsi. …always iced it. Less heat. Lessenergy. Less motion in themolecules.”
Tony Hillerman, 1986:Skinwalkers, pp. 37-38.
Science quotes of 5th and 6th graders -
A vibration is a motion that cannot make upits mind which way it wants to go.
Climate and Global Change Notes
3-6
Observing Climate - TemperatureBoiling Point of Water at Various Altitudes and Pressures
Observing Climate - TemperatureTemperature Scales• Olef Roemer (Danish) and Isaac Newton (English) first to stress using two
reference points to calibrate thermometers • Newton used boiling and freezing points of water to calibrate his temperature
scale.
• Roemer used the boiling point of water and the temperature of a mixture of ice, water and salt (colder than freezing) to calibrate his temperature scale, but designated 60° between the two points.
• Gabriel Fahrenheit (Dutch) developed mercury thermometer (1714 - more accurate and could be divided into smaller divisions). In 1724, like Roemer, used temperature of a mixture of ice, water and salt as 0°, but unlike Roemer, used human temperature as 96°. Scale made explicitly for meteorology.
Climate and Global Change Notes
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Observing Climate - TemperatureThermometer Types
• Liquid-in-glass thermometer wasinvented about 1650 by theGrand Duke of Tuscany,Ferdinand II. Used “spirits ofwine” as the liquid.
- Mercury (Freezes at-38.9°F)
- Alcohol
- Max-Min thermometer
Note: Scales are reversed on the right and left sides of the thermometer
Observing Climate - TemperatureThermometer Types (Con’t)• Electric
- Resistance
Thermometer Exposure• Shade
• Ventilation
• Dry
• Height - Shelter 4 ft above ground
• Location - Grassy area away from trees
• Forestry Suppliers cotton region instrumentshelter - Wood construction with 48” wood ormetal legs. Painted white. Louvered on allsides and vented through the bottom to provide
ambient conditions inside while excluding radiation and precipitation. A doubleroof provides added protection against direct solar radiation.
Observing Climate - TemperatureTemperature Scales (Con’t)• Today's Fahrenheit (Daniel Gabriel 1686-1736) scale based on freezing point
(32°) and boiling point (212°) of water. Human temperature is 98.6°.
• 1742 Swedish astronomer Anders Celsius (1701-1744) revised a temperature scale using, like Newton, the freezing and boiling points of water as calibration points, but used 100° between the two points, i.e., the Centigrade scale.
Quote“The wind was particularly bitter, even for January in Holloman, Connecticut. WhenDr. Joshua Christian strode round the corner from Cedar Street onto Elm Street it hithim full in the face, a stream of arctic air with fangs and talons of ice chewing andclawing at the little sections of facial skin he had to expose to see where he going.”
Colleen McCullough, "A Creed For The Third Millennium"
What is wind chill?
Definition• Wind Chill Temperature Index (WCTI) is an effective
temperature not an actual temperature
• Wind Chill Temperature Index is related to an object'srate of cooling
Observing Climate - Wind ChillQuote“The wind was particularly bitter, even for January in Holloman, Connecticut. WhenDr. Joshua Christian strode round the corner from Cedar Street onto Elm Street it hithim full in the face, a stream of arctic air with fangs and talons of ice chewing andclawing at the little sections of facial skin he had to expose to see where he going.”
Colleen McCullough, "A Creed For The Third Millennium"
What is the wind chill temperature? How cold was it?
When the farmers wentto milk their cows, theygot ice cream.
Bulletin of the AmericanMeteorological Society,2005: Coin-a-phenomenon #3, 86,1221.
Climate and Global Change Notes
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Observing Climate - Wind ChillDefinition (Con’t)• Late 40s, Siple and Passel, Antarctic explorers, measured time it took to freeze
250 g of water in a plastic contained on a pole in different temperature andwind conditions
• Developed empirical equations relating these data to the rate of heat loss fromexposed human skin
T (Chill) = 33 - ( 10.45 + 10 * SQRT ( V ) - V ) * ( 33 - T ) / 22.04
where V is in units of m / s and T is in °C
or
T (Chill) = 0.0817 ( 3.71 * SQRT ( V ) + 5.81 - 0.25 V ) * ( T - 91.4 ) + 91.4
where V is in units of mph and T is in °F. At wind speeds of 4 mph or less,the Wind Chill Temperature Index is the same as the actual air temperature.
Siple, P.A., and C.F. Passel, 1945: Measurements of dry atmosphericcooling in subfreezing temperatures. Proc. Amer. Philos. Soc., 89, 177-199.
Climate and Global Change Notes
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Observing Climate - Wind ChillDefinition (Con’t)• 1 November 2001, the Weather Service began using a new Wind Chill
Temperature Index (WCTI) equation. New WCTI equation uses:
- Calculated wind speed at an average height of 5 ft (typical height of anadult human face)
- A human face model- Modern heat transfer theory- A calm wind threshold of 3
mph- A consistent standard for
skin tissue resistance- No impact from the sun
(i.e., clear night sky).
T (Chill) = 35.74 + 0.6215 T- 36.75 V0.16 + 0.4275 T V0.16
where V is in mph and T in °F.For wind speeds less than 3 mph,the new Wind Chill TemperatureIndex equals the actual airtemperature. http://www.nws.noaa.gov/om/windchill/
Osczevski, R., and M. Bluestein, 2005: The new wind chill equivalenttemperature chart. Bull. Amer. Meteor. Soc., 86, 1453-1458.
Heat Index 90-104Prolonged exposure and physical activity (especially if in poor physical conditionand overweight, sedentary lifestyle) likely to lead to heat exhaustion.
Heat Index 105-129Heat exhaustion possible with prolonged exposure and physical activity, even ifin good physical condition unless hydration is maintained.
Heat Index >130Do not engage in strenuous physical activity.