GEOL 106 Lecture Notes - Lecture 29: Joule, Atmospheric Circulation, Thunderstorm
25 May 2018
School
Course
Professor
[Type here]
Reading for Week 9: CHAPTER 9 TEXTBOOK NOTES
9.1 Energy
- work is done when energy is expended
- joule: force of 1N applied over distance of 1m
- 10 trillion joules associated with typical thunderstorm
- average hurricane expends 100 000 times that amount of work
- power: rate at which work is done
- for atmospheric processes: use exajoules (EJ) → one EJ is 1 quintillion (10^8) joules
- solar energy primarily heats the surface of planet, evaporates water, produces differential heating
that causes air masses to move across our landscapes
TYPES OF ENERGY
- must expend energy to do work
- energy = ability to do work → kinetic, potential, heat energy
o heat = kinetic energy of atoms or molecules within substance
- two types of heat important in atmospheric processes
o sensible heat and latent heat
1. sensible: heat that may be sensed or measured by thermometer
2. latent heat: amount of heat that is either absorbed or released when substance changes
phase (from solid to liquid)
a. in atmosphere: latent heat is related to 3 phases of water: ice, liquid water, water
vapour
b. evaporation of water: involves phase change from liquid to water vapour (gas)
1. latent heat of vaporization = heat required for this
2. recoverable when water vapour changes back to liquid through
condensation in atmosphere when moist air cools and water droplets
form
HEAT TRANSFER
- 3 major heat transfer processes:
1. conduction: relies on T differences causing heat to flow through substance from greater to
lesser T
a. occurs in atmosphere, on land, bodies of water → but it is least important in
atmosphere
b. air is poor conductor of heat → trapped air is used to increase insulation value of
goose down comforters, windows etc.
2. convection: mass movement of fluid such as water or air
a. important process for transfer of atmospheric heat in thunderstorms and in large
scale circulation of warm air from equator
3. radiation: oscillations in electromagnetic waves
9.2 Earth’s Eergy Balace
- eath’s eegy alae: geeal euiliiu etee ioig ad outgoig eegy
o some of energy changes form but its neither created nor destroyed
- earth intercepts only a tiny fraction of total energy mitted by sun
find more resources at oneclass.com
find more resources at oneclass.com
