ATM OCN 100 - Summer 2000 LECTURE 5

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ATM OCN 100 - Summer 2000LECTURE 5

• AIR TEMPERATURE A Fundamental Weather Element
• A. BACKGROUND
• B. THERMOMETRY
• C. CLIMATOLOGY of NEAR-SURFACE AIR TEMPERATURE

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C. THE CLIMATOLOGY of NEAR-SURFACE AIR
TEMPERATURE (cont.)

• Average Daily Temperatures Degree-Day Units
• Background
• Types of Degree-Day Units
• Heating Degree-Day Units
• Cooling Degree-Day Units
• Growing Degree-Day Units
• Degree-Day Units Computations
  (where...)

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DEGREE-DAY CALCULATIONS

• Calculate daily average temperature then
  Heating Degree-Day Units

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HEATING DEGREE-DAY CALCULATION

• If Tmax 40oF and Tmin 30oF, then

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DEGREE-DAY CALCULATIONS

• Calculate daily average temperature then
  Cooling Degree-Day Units

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COOLING DEGREE-DAY CALCULATION

• If Tmax 80oF and Tmin 60oF, then

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D. VARIATION OF OBSERVED AIR TEMPERATURE WITH
HEIGHT

• Temperature lapse rates
• Rate of cooling with height
• Units degrees per meter or feet or kilometers
• Layer nomenclature
• lapse
• inversion
• isothermal
• where ...

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LAPSE CONDITIONSTemperature decreases with height
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INVERSION CONDITIONS Temperature increases with
height
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ISOTHERMAL CONDITIONS Temperature remains
constant with height
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VERTICAL TEMPERATURE VARIATIONS (cont)

• The Standard Reference Atmosphere
• The Temperature Spheres
• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• The boundaries or pauses

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U.S. STANDARD ATMOSPHERE
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VERTICAL TEMPERATURE VARIATIONS (cont)

• The Standard Reference Atmosphere
• The Temperature Spheres
• The boundaries or pauses
• Reasons for vertical temperature structure
• Implications of vertical temperature structure

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RADIOSONDE LOCATIONS
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ATM OCN 100 - Summer 2000LECTURE 4A

• ATMOSPHERIC ENERGETICS HEAT, ENERGY ENERGY
  TRANSPORT
• A. INTRODUCTION
• What maintains the operation of our planetary
  system?

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B. ENERGY POWER

• Definitions
• Energy Ability of a system to do
  work.
• Power Time rate of energy production
  or consumption.
• Importance

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B. ENERGY POWER (cont.)

• Types of Energy (In the Atmosphere)
• Kinetic
• Potential
• Radiant
• Internal or heat energy
• Chemical
• Physical phase Transformation
• Electrical

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B. ENERGY POWER (cont.)

• Energy Units
• British Thermal Units (BTU)
• Calories
• Joules
• Power Units
• Watts

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C. ENERGY EXCHANGE PROCESSES

• Conservation of energy
• Energy cannot be created or destroyed
• Energy can change forms
• Energy can be transported
• Specification by Thermodynamics Laws.
• Energy transport Requirements
• From high energy (hot) to low energy (cold).

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C. ENERGY EXCHANGE PROCESSES (cont.)

• Types of energy exchange or transport modes
• Conduction
• Convection
• Radiation where...

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ENERGY TRANSPORT CONDUCTION

• Energy transfer by molecular vibrational
  motion.
• Requires molecular contact Transport medium is
  typically a solid.
• In general
• Metals are good heat energy conductors
• Air is a poor heat conductor.

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ENERGY TRANSPORT CONVECTION

• Energy Transport by molecular motion through
  bulk transport.
• Requires movement of medium Transport medium is
  a fluid only.
• In general
• Fluid density differences drive convection
• Convection works well in air water.

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ENERGY TRANSPORT RADIATION

• Energy Transport is by radiating disturbances
  in electrical magnetic fields.
• Does not requires a medium Transport most
  efficient in vacuum.
• Radiation is important for maintenance of
  planetary climate.

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D. HEAT (or HEAT ENERGY)

• Definition
• A form of energy
• Proportional to total amount of thermal energy
  found in object.
• Important considerations
• Heat Flow
• Requires a temperature difference
• Flow from hot to cold.
• Sensible heat Vs. Latent heat
  where ...

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D. HEAT ENERGY (cont.)

• Sensible heat
• Feelable Heat
• Measurement of heat thermal energy
• Change in heat constant x temperature
  change
• Latent heat
• Hidden Heat
• Involves Physical Phase Transformation
• No temperature change.

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E. A PRACTICAL EXAMPLE

• WIND-CHILL WIND-CHILL EQUIVALENT TEMPERATURE
• What do these terms mean?
• Human significance.

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WIND-CHILL WIND CHILL EQUIV. TEMP.BACKGROUND

• HEAT LOSS FROM HUMANS
• Radiation
• Convective Heat Loss
• Latent Heat Loss.
• CONVECTIVE HEAT LOSS depends upon
• Difference between skin air temperature
• Wind speed.

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THE DEFINITIONS

• WIND-CHILL
• A form of heat energy loss
• Proportional to
• air temperature
• wind speed.
• Units kcal/square meter/hour

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THE DEFINITIONS (cont.)

• WIND-CHILL EQUIVALENT TEMPERATURE
• A temperature-based index
• Air temperature for calm conditions that produces
  same convective heat loss as actual combination
  of ambient air temperature wind speed
• Units degrees Fahrenheit (or Celsius).

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HUMAN COMFORT SAFETYCold Stress

• FROST BITE
• HYPOTHERMIA