Discussion 3 Wednesday 2/13 Quiz review + lectures 4-6

Quiz multiple choice Most common gas? O 2 Ar N 2 CO 2 He Closest to the Earth? Thermosphere – Mesopause Mesosphere – Stratopause Stratosphere – Tropopause Troposphere Earth

Quiz multiple choice Stratospheric warming? Density increases Captures heat radiated from Earth Borders thermosphere Contains ozone Thermosphere – Mesopause Mesosphere – Stratopause Stratosphere – Tropopause Troposphere Earth

Essay redux – most common errors Carbon cycle Ocean both sink and source Carbonates are a sink Sinks and sources are NOT in equilibrium – e.g. Keeling curve Water cycle Transpiration (or at least one of the –ation’s) Groundwater Glaciers/ice caps Biosphere

Lecture 4: Insolation Earth’s tilt & the seasons Angle of incidence & solar zenith angle Earth’s energy budget – Insolation and re-radiation – Latitudinal heat balance – The greenhouse effect

Fig. 2-12, p. 42 HEATING OF THE EARTH’S SURFACE DEPENDS ON THE AMOUNT OF SOLAR RADIATION PER UNIT AREA. SAME AMOUNT OF RADIATION IS DISTRIBUTED OVER A LARGER AREA IN A THAN IN B. RADIATION PER UNIT AREA IS LESS IN A THAN IN B. LESS HEATING IN A THAN IN B.

Latitudinal Heat Balance

Simple Greenhouse Model But this doesn’t factor in the atmosphere! 254K vs 288K

Lecture 5+6: Temperature controls Diurnal cycle Geographic controls – Latitude – Surface type – Elevation – Aspect Long-term control – Cloud cover – Albedo – Ocean currents – Differential heating of land and water

Miami NYCChicago STL Denver Santa Fe LA

Lecture 6: Heating, cooling, and stability Adiabatic processes Equilibrium and lapse rates Temperature Inversions Wind Chill

Ideal gas law: P=dR’T :: PV=nRT Adiabatic process: no heat added or removed – P(V γ )=const., T(V γ-1 )=const. Adiabatic lapse rate (T change with height) – Dry: ≈10 o C / km (really 9.8) – Wet: depends on water content, always less than dry rate; ≈6 o C / km Adiabatic Expansion and Compression

Equilibrium in the atmosphere

Fig. 3-19, p. 75 Lifecycle of a nocturnal (radiative) temperature inversion (A)Mid-afternoon (B)Evening (C)Sunrise (D)Mid-morning Fig. 3.12

Wind Chill Factor The wind chill factor describes the increased loss of heat by the body due to the movement of air. The wind causes an increased rate of evaporation of perspiration from the skin.. It cannot be measured, so it is calculated Wind chill equivalent temperature