Chapter 2 Solar Energy, Seasons, and the Atmosphere

Supplemental notes are drawn from Lutgens and Tarbuck, The Atmosphere

Seen from space, the Earth looks like no other planet that we know “Big Blue Marble”

--- nothing as much as weather From pre-history Man has been directly and indirectly affected by environment --- nothing as much as weather --- Sun God; Rain God; omens; reward/punishment; etc --- SAD

Weather: the state of the Earth’s atmosphere with respect to heat or cold; wetness or dryness; clearness or cloudiness (Webster) --- atmospheric extent is conceptual --- manifest in wind; temperature; storms; precipitation; etc

[I do not like terming climate as “average weather”] Climate: weather of a location over an extended period of time, including its extremes [I do not like terming climate as “average weather”]

Atmospheric Composition variant vs non-variant gases nitrogen oxygen water vapor trace elements (CO2; O3) dust industrial exhaust (NOx; SOx) insolation vs terrestrial radiation

Composition of the Homosphere Figure 2.19

Ozone (O3) Stratospheric Tropospheric --- VOCs and NOx --- Corrosive --- Biological irritant (a secondary pollutant) --- compliance measured as hourly average (0.085ppm)

Ozone (O3), cont Factors affecting O3 [and pollutants in general] --- human/economic … industrial mix … transportation --- physical … wind … atmospheric stability and inversions … topography … severe air pollution potential

Photochemical Smog Figure 2.26

Origin of Atmosphere - First atmosphere of light gases disappear to space - “degassing” and “dissolving” - plants absorb CO2, release O2

Vertical Structure of the Atmosphere Atmosphere structure is based on: (1) pressure (2) temperature (3) vertical variation in composition --- Homosphere --- Heterosphere

Atmospheric Pressure Figure 2.18

Temperature Profile Figure 2.20

Temperature Inversion Figure 2.24

Profile of Atmosphere Figure 2.17

Atmospheric Composition Heterosphere – Outer Atmosphere 80 km (50 mi) outwards, to thermosphere Layers of gases sorted by gravity Homosphere – Inner Atmosphere Surface to 80 km (50 mi) Gases evenly blended

Atmospheric Temperature Criterion Thermosphere 80 km (50 mi) outwards Mesosphere 50 to 80 km (30 to 50 mi) Stratosphere 18 to 50 km (11 to 31 mi) Troposphere Surface to 18 km (11 mi)

Heating of the Atmosphere Radiation Conduction Convection / Advection Latent Heat of Condensation

Average Breakdown of Insolation Absorbed by atmosphere – 19%-22% Reflected into space – 34% Absorbed Earth surface – 43%-47%

Heat Energy Budget Insolation to the Ground 47% of incoming solar radiation reaches the surface of the Earth … ultimately returned to the atmosphere terrestrial radiation – 14% conduction/convection – 10% latent heat – 23%

Protective Atmosphere Figure 2.21

The Electromagnetic Spectrum Figure 2.6

Solar and Terrestrial Energy Figure 2.7

Earth’s Energy Budget Figure 2.8

Controls on Weather and Climate Latitude Land-Water Ocean Currents Altitude Physical Barriers Human Activities Pressure systems and storms

Short Term Variations in Temperature Daily affects of insolation Cloud cover Differential heating (land/water) Reflection Horizontal Air Movement

Variation in the Heat Energy Balance Regions of Energy Surplus --- tropical zones --- seasonal Regions of Energy Deficit --- polar zones

Figure 2.9

Daily Net Radiation Figure 2.10