Weather and Climate(Lecture 2)Instructor: Prof. Michael C. MorganTeaching Assistant: Dianna N. Nelson
Questions from last lecture
The composition of the early atmosphere ismuch the same as it is today.A. TrueB. False
Much of the oxygen in the atmosphere wasoutgased from volcanoes.A. TrueB. False
Which gas is most abundant in theatmosphere?A. ArgonB. NitrogenC. OxygenD. Carbon Dioxide
What about the temperatureof our atmosphere?The vertical structure oftemperature in our atmosphere isvery complex!
Vertical structure of the atmosphere• Troposphere– Where our weathertakes place– In general:Temperaturedecreases as heightincreases– Structure is due tosurface radiation
Vertical structure of the atmosphere•Tropopause– Boundary betweenTroposphere andStratosphere– Temperature profileis “isothermal”•isothermal constanttemperature withheight
Vertical structure of the atmosphere• Stratosphere– Warms with height– Yet, is still very cold!– Temperature profileis the result of ozone(O 3 )– Ozone absorbsultraviolet solarenergy
Vertical structure of the• Stratopause– Boundary betweenstratosphere andmesosphere– Like the tropopause,it is “isothermal”atmosphere
Vertical structure of the atmosphere• Mesosphere–Temperaturedecreases withheight– Mostly N 2 and O 2(like the surface), butvery little ozone (O 3 )– At 85 km above theearth’s surface isabout –130 o F(brrr.....cold!)
Vertical structure of the atmosphere•Mesopause– Boundary betweenthe mesosphere andthermosphere–Temperature is“isothermal”
Vertical structure of the atmosphere•Thermosphere–Temperatureincreases with heightdue to the absorptionof sunlight bymolecular O 2– Very, very fewnumber of atoms,thus changes in solarradiation candrastically changethe temperature
What is “Energy”?• By definition, energy is the ability or capacity todo work on some form of matter.• Energy comes in many different forms:– Kinetic energy– Potential energy– Radiant energy– Chemical energy– Electric energy– Magnetic energyEnergy is measured in Joules (J)
Potential Energy• The energy that a body possesses by virtue ofits position with respect to other bodies in thefield of gravity. That is:PE=mghWhere m=mass of object,g= gravityh=height of object above ground
Kinetic Energy• The energy within a body that is the resultof its motion.KE= 1 / 2 mv 2Where m=mass of objectv=velocity of object• If a volume of water and an equal size volumeof air were moving at the same speed, whichwould have the greater kinetic energy?
1 st Law of Thermodynamics“Energy cannot be creatednor can it be destroyed.”• Energy can change form………that is, the energy lost during one processmust equal the energy gained duringanother.