Heat Transfer and the Atmosphere

1. Heat Transfer and the Atmosphere Chapter 5

2. Heat Transfer and the Atmosphere The transfer of heat is normally from a high temperature object to a lower temperature object. Heat transfer changes the internal energy of both systems involved according to the First Law of Thermodynamics. Chapter 5

3. Heat Transfer and the Atmosphere • 1 Joule = 1 N*m = 1 kg m/s2 * m • 1 calorie is the heat energy needed to raise 1 gram of water by 1 degree Celsius. • 1 calorie = 4.186 Joules. • 1 Calorie = 1000 calories.

4. Heat can be transferred by: • Conduction • Convection • Advection • Radiation

5. Heat can be transferred by: • Conduction • Convection • Advection • Radiation

6. is the transfer of heat within a substance, molecule by molecule Conduction

7. is the transfer of heat within a substance, molecule by molecule Conduction This is a listing of the heat conductivity of various substances:

8. Heat can be transferred by: • Conduction • Convection • Advection • Radiation

9. Convection is heat transfer by the mass movement of a fluid in the vertical (up/down) direction. This type of heat transfer takes place in liquids and gases. This occurs naturally in our atmosphere.

10. Heat can be transferred by: • Conduction • Convection • Advection • Radiation

11. Advection • Advection is the transfer of heat in the horizontal (north/east / south/west) direction. In meteorology, the wind transports heat by advection. This happens all the time on Earth, heat is transported in many ways.

12. Radiation • Radiation allows heat to be transfered through wave energy. These waves are called Electromagnetic Waves, because the energy travels in a combination of electric and magnetic waves. This energy is released when these waves are absorbed by an object. The energy a wave carries is related to its wavelength (measured from crest to crest). Shorter wavelengths carry more energy than longer wavelengths. Wavelengths are measured in terms of meters: (millimeter) mm (micrometer) μm (nanometer) nm Note / All things with a temperature above absolute zero emit radiation.

13. Electromagnetic spectrum

14. Emitted radiation can be • Absorbed: Increasing the internal energy of the gas molecules. • Reflected: Radiation is not absorbed or emitted from an object but it reaches the object and is sent backward. The Albedo represents the reflectivity of an object and describes the percentage of light that is went back. • Scattered: light is deflected in all directions, forward, backward, sideways. It is also called diffused light. • Transmitted: Radiation not absorbed, reflected, or scattered by a gas, the radiation passes through the gas unchanged.

15. The temperature of an object can tell us something about the emitted radiation. • Stefan-Boltzmann law E = σT4 • Wien's lawλmax = θ/T θ is a constant equal to 2897 μm K • Kirchhoff's Law says that good absorbers of a particular wavelength are also good emitters of that wavelength, and poor absorbers of a wavelength are also poor emitters at the same wavelength.