230 likes | 592 Views
Composition of the Atmosphere. Today’s Objectives. Students will be able to:. Distinguish gases between fixed, variable, and particulate Identify the Greenhouse gases Describe each type of gas Discuss the role of each gas in the atmosphere. 3 Major Compositional Components.
E N D
Today’s Objectives Students will be able to: • Distinguish gases between fixed, variable, and particulate • Identify the Greenhouse gases • Describe each type of gas • Discuss the role of each gas in the atmosphere
3 Major Compositional Components • The Fixed Gases • The Variable Gases • The Particulates (aerosols) Lets look at each of these now
Fixed Gases • the same ratio around the planet • Nitrogen (N2) – • Oxygen (O2) – • Argon (Ar) – • Neon (Ne) • Helium (He) • Hydrogen (H) • Xenon (Xe) 78.08% (78%) 20.95% (21%) 0.93% (1%) very trace amounts
Properties of Fixed Gases • Nitrogen – Inert Gas • Oxygen – “multi-talented” • Organisms use in respiration • Used in combustion • A major Greenhouse gas • Argon – Inert gas • *residual from the first atmosphere*
Variable Gases • H2O Vapor – 0-4% • Carbon dioxide (CO2) – 0.036% • (365 ppm) • Methane (CH4) – 1.7 ppm • Nitrous oxide (N2O) – 0.3 ppm • Ozone (O3) – 0.04 ppm
Water Vapor – 0-4% • Clear, tasteless, odorless • Major part of Hydrologic Cycle • Used for energy exchange • evaporation (absorption) • condensation (release) • Latent Heat Flux (can’t feel) • Greenhouse Gas
Carbon dioxide – 365 ppm • Oceans have about 10x more • Product of combustion • Ohio 7th largest producer • in the? • Greenhouse Gas • 315 ppm in 1958 50 ppm in 42 yrs • Goes down in summer time – leaves • Enhanced Greenhouse Effect World True What About Global Warming?
Methane – 1.7 ppm • Greenhouse Gas • Fastest growing component • 0.5% per year increase • Most potent • Where is its origin? • Breakdown of plant material by bacteria in rice paddies • Termite activity • Biochemical reactions in stomachs of cows COW FARTS…eww!!
Nitrous Oxide – 0.04 ppm • Commonly known as laughing gas • Increasing 0.25% per year • Greenhouse Gas • Forms in soil through a chemical process involving bacteria and certain microbes. (mutualism) • Ultraviolet (UV) light destroys it
Ozone – 0.04 ppm • 2 types – surface & atmospheric • Surface – BAD!!!!!!(Photo-smog) • Stratosphere – GOOD • Higher concentration - 5-12 ppm • Absorbs harmful UV light from Sun • 97% is found here • Destroyed by Chlorofluorocarbons • (CFC’s) – dreaded hole in ozone layer
Particulates (aerosols) • Dust, sand, & soil from erosion • Salt particles from the ocean • Smoke and ash from forest fires • Ash and gas from volcanism • Pollution from … who else MAN! • The nuclei for H2O to condense on
Condensation Nuclei • Hygroscopic - “water seeking” • H2O vapor condenses readily on this type of surface <100% humidity. • Ocean salt is a common particle • Not all good - sulfuric & nitric acid
Condensation Nuclei • Hydrophobic – “water-repelling” • H2O vapor does not condense on these surfaces even when > 100% humidity • Oils, gasoline, waxes are examples