SO345: Atmospheric Thermodynamics

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SO345 Atmospheric Thermodynamics

• CHAPTER 2 INTRODUCTION FUNDAMENTALS

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INTRODUCTION FUNDAMENTALS

• The study of Atmospheric Thermodynamics is a more
  in-depth look at the concepts of basic
  meteorology through the languages of physics and
  mathematics. For a sufficient understanding of
  the principles of this course, prerequisite
  knowledge from the following subjects is
  therefore required
• Basic Chemistry
• General Physics
• Algebra
• Differential Calculus
• Integral Calculus
• Basic Meteorology

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IS THIS A SYSTEM?
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INTRODUCTION FUNDAMENTALS

• WHAT IS THERMODYNAMICS ?
• Thermodynamics is "the study of heat and
  energy within a system". A slightly more focused
  view can be stated as "the study of the initial
  equilibrium state and an energy process to a
  final equilibrium state".

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INTRODUCTION FUNDAMENTALS

• WHAT IS THERMODYNAMICS ?
• Example - the energy process could be cooling
  which results in the final state of a system
  being 5 degrees colder than the original state.
  The cooling could also be to such a degree that a
  change in phase from gas to liquid (water vapor
  condensing to cloud liquid water) occurs.

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INTRODUCTION FUNDAMENTALS

• WHAT IS THERMODYNAMICS ?
• Significant energy processes are occurring
  everyday in the atmosphere. These energy
  processes of cooling, heating, evaporation,
  condensation, etc. are responsible for the
  weather we experience everyday. The massive
  amounts of energy from destructive weather
  phenomena such as tornadoes, hurricanes, or
  severe thunderstorms outline the importance of
  understanding thermodynamic concepts in the
  atmosphere.

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INTRODUCTION FUNDAMENTALS

• WHAT IS THERMODYNAMICS ?
• IMPORTANT LAWS OF PHYSICS
• Some of the more significant physical laws
  that govern Atmospheric Thermodynamics will be
  used throughout the course
• Equation of State (Ideal gas law)
• First Law of Thermodynamics
• Second Law of Thermodynamics

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INTRODUCTION FUNDAMENTALS

• BASIC LAWS OF THERMODYNAMICS
• Equation of State of a Perfect Gas
• (Ideal Gas Law)
• For an ideal gas, this defines the relationship
  between the variables of
• - pressure,
• - temperature,
• - (specific) volume.

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INTRODUCTION FUNDAMENTALS

• BASIC LAWS OF THERMODYNAMICS
• First Law of Thermodynamics
• This law expresses the relationship between heat
  energy, internal energy, and work.

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INTRODUCTION FUNDAMENTALS

• BASIC LAWS OF THERMODYNAMICS
• Second Law of Thermodynamics
• One form of this law states that nature tends
  toward a state of greater disorder.

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INTRODUCTION FUNDAMENTALS

• OTHER IMPORTANT LAWS OF PHYSICS
• Newtons Laws of Motion
• 1. Bodies in motion..
• 2. Fma
• 3. For every action.
• Mass Continuity Equation
• Mass and Energy Conservation
• Ekmans Law

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INTRODUCTION FUNDAMENTALS

• FUNDAMENTAL DIMENSIONS
• All quantities we will be dealing with can be
  expressed in terms of the fundamental dimensions
  of
• Length L
• Mass M
• Time t
• Temperature T
• (Fundamental dimensions will be in square
  brackets )
• Some quantities, pure numbers, are dimensionless
• (e.g., angles, logarithms and trigonometric
  functions)

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INTRODUCTION FUNDAMENTALS

• UNITS OF MEASURE
• A unit differs from a dimension in that a
  unit assigns a standard of measure for a
  dimension. The simplest illustration is probably
  through a short list of examples
• Dimension Unit
• Length meter / foot / centimeter / furlong
• time second / hour / day / fortnight
• mass kilogram / gram / pound

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INTRODUCTION FUNDAMENTALS

• UNITS OF MEASURE
• The different systems of units are
• meter-kilogram-second . . . . (mks)
• centimeter-gram-second . . . (cgs)
• foot-pound-second . . . . . . . . (fps)
• We will be primarily dealing with the mks system
  of units, also known as the SI units.

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INTRODUCTION FUNDAMENTALS

• UNITS OF MEASURE
• Note that the unit of temperature may be in
  either degrees Celsius (Centigrade) or in the
  absolute reference of degrees Kelvin. We will
  discuss the difference between these two
  temperature scales and preferences shortly.

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ATMOSPHERIC COMPOSITION STRUCTURE