meteorology notes 2

• Potential energy


  Energy based on position
• Potential energy


  • Higher position or larger mass results in a greater potential energy measure
  • Potential energy = mgh
• Cold air masses often have higher potential energy because they can release this stored energy in the form of kinetic energy (wind) or convective activity (storms) when they encounter warmer air masses or other atmospheric disturbances

  
• Cold air masses


  Can release stored potential energy as kinetic energy (wind) or convective activity (storms) when encountering warmer air masses or atmospheric disturbances

  
• This release of energy can lead to various weather phenomena such as thunderstorms, tornadoes, or strong winds
• In hot air, the molecules are moving faster on average compared to cold air
• Temperature is a measure of the average kinetic energy of the molecules in a substance
• When air is heated, its molecules gain kinetic energy and move more rapidly, resulting in higher internal energy
• Parcel B has larger internal energy than Parcel A
• Celsius to Kelvin


  Tk = Tc + 273
• Kelvin to Celsius


  Tc = Tk - 273

  
• Celsius to Fahrenheit


  Tf = 1.80Tc + 32
• Fahrenheit to Celsius


  Tc = (Tf - 32) / 1.80
• Heat capacity


  Ratio of the amount of heat absorbed by a substance to its temperature rise
• Specific heat capacity


  Amount of heat needed to raise the temperature of 1 gram of a substance by 1 degree Celsius
• Phase changes


  1. Ice to vapor = sublimation

  2. Vapor to Ice = deposition

  3. Liquid to Ice = frosting
• Freezing, condensation, and deposition all warm their surroundings
• Melting, evaporation, and sublimation all cool the environment
• Conduction


  Transfer of heat through direct contact between particles, via molecular movement

  
• Warm ground surfaces heat overlying air by conduction

  
• Temperature inversion


  Layer of warmer air above cooler air near the earth's surface, contrary to the usual decrease in temperature with altitude

  
• Air is a poor conductor of heat
• In northern latitudes, the oceans are warmer in summer than they are in winter


  Oceans lose heat more rapidly to the atmosphere by conduction in winter

  
• Convection


  Transfer of heat through the movement of fluids (liquids or gases)
• When the sun heats up the ground, the air near the ground gets warmer and rises, while cooler air moves in to take its place

  
• Free convection


  Uneven heating of air in the atmosphere, creating pockets of warmer and cooler air, leading to the rise of warmer air and sinking of cooler air

  
• Strong free convection can lead to the formation of clouds and thunderstorms

  
• Radiation


  Transfer of heat by electromagnetic waves
• The sun sends out a lot of radiation, and a portion of it reaches the Earth, warming its surface

  
• Different things on Earth absorb this radiation, and when they do, their temperature goes up

  
• The absorbed radiation is then given off as heat through convective heat transfer to the surrounding air
• Black body radiation


  Perfect emitter and absorber of radiation, emitting radiation at all wavelengths over a continuous range
• The sun and the Earth's surface behave approximately as black bodies
• Humans emit black body radiation because they are warm objects
• Wien's Displacement Law


  The wavelength of maximum emission (λmax) of a black body is inversely proportional to its temperature
• Stefan-Boltzmann Law


  The rate of loss of radiant heat by unit area of a body is directly proportional to the 4th power of its absolute temperature
• Atmospheric gases and clouds absorb another 19% of incoming shortwave radiation, leaving 51% absorbed by the Earth's surface

  
• Radiative equilibrium


  The rate of absorption of incoming radiation by an object or system is equal to the rate of emission of outgoing radiation, resulting in a relatively constant temperature

  
• The Earth's global average temperature is constant with time due to radiative equilibrium
• Albedo


  The reflectiveness of a substance - how much it absorbs and how much it reflects