ATM OCN 100 - Summer 2000 LECTURE 5 - PowerPoint PPT Presentation

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ATM OCN 100 - Summer 2000 LECTURE 5

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C. THE CLIMATOLOGY of NEAR-SURFACE AIR TEMPERATURE (con't.) Average Daily Temperatures ... Calculate daily average temperature & then Heating Degree-Day Units: ... – PowerPoint PPT presentation

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Title: ATM OCN 100 - Summer 2000 LECTURE 5


1
ATM OCN 100 - Summer 2000LECTURE 5
  • AIR TEMPERATURE A Fundamental Weather Element
  • A. BACKGROUND
  • B. THERMOMETRY
  • C. CLIMATOLOGY of NEAR-SURFACE AIR TEMPERATURE

2
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...)

3
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4
DEGREE-DAY CALCULATIONS
  • Calculate daily average temperature then
    Heating Degree-Day Units

5
HEATING DEGREE-DAY CALCULATION
  • If Tmax 40oF and Tmin 30oF, then

6
DEGREE-DAY CALCULATIONS
  • Calculate daily average temperature then
    Cooling Degree-Day Units

7
COOLING DEGREE-DAY CALCULATION
  • If Tmax 80oF and Tmin 60oF, then

8
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 ...

9
LAPSE CONDITIONSTemperature decreases with height
10
INVERSION CONDITIONS Temperature increases with
height
11
ISOTHERMAL CONDITIONS Temperature remains
constant with height
12
VERTICAL TEMPERATURE VARIATIONS (cont)
  • The Standard Reference Atmosphere
  • The Temperature Spheres
  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • The boundaries or pauses

13
U.S. STANDARD ATMOSPHERE
14
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

15
RADIOSONDE LOCATIONS
16
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18
ATM OCN 100 - Summer 2000LECTURE 4A
  • ATMOSPHERIC ENERGETICS HEAT, ENERGY ENERGY
    TRANSPORT
  • A. INTRODUCTION
  • What maintains the operation of our planetary
    system?

19
B. ENERGY POWER
  • Definitions
  • Energy Ability of a system to do
    work.
  • Power Time rate of energy production
    or consumption.
  • Importance

20
B. ENERGY POWER (cont.)
  • Types of Energy (In the Atmosphere)
  • Kinetic
  • Potential
  • Radiant
  • Internal or heat energy
  • Chemical
  • Physical phase Transformation
  • Electrical

21
B. ENERGY POWER (cont.)
  • Energy Units
  • British Thermal Units (BTU)
  • Calories
  • Joules
  • Power Units
  • Watts

22
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).

23
C. ENERGY EXCHANGE PROCESSES (cont.)
  • Types of energy exchange or transport modes
  • Conduction
  • Convection
  • Radiation where...

24
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.

25
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.

26
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.

27
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 ...

28
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.

29
E. A PRACTICAL EXAMPLE
  • WIND-CHILL WIND-CHILL EQUIVALENT TEMPERATURE
  • What do these terms mean?
  • Human significance.

30
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.

31
THE DEFINITIONS
  • WIND-CHILL
  • A form of heat energy loss
  • Proportional to
  • air temperature
  • wind speed.
  • Units kcal/square meter/hour

32
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).

33
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34
HUMAN COMFORT SAFETYCold Stress
  • FROST BITE
  • HYPOTHERMIA
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