2. Click to listen

4. Early atmosphere ~4.5 billion years ago Mostly Hydrogen and Helium Escaped into space Outgassing of water vapor and CO2 created a secondary atmosphere with some nitrogen As liquid water formed the oceans and CO2 was removed from atmosphere The atmosphere became dominated by nitrogen. ~ 2 billion years ago oxygen increased in the atmosphere because of plant life and photosynthesis.

5. 78 % Nitrogen N 2 20.95 % Oxygen O 2 0.93 % Argon Ar H 2 O 0 to 4 % Carbon Dioxide CO 2 0 to.037 % (or 370 ppm) Methane CH 4 1.8 ppm Nitrous Oxide N 2 O.3 ppm Ozone 0.04 ppm or 40 ppb) Aerosols (particles) highly variable Click to listen

11. Mass - quantity of matter Weight = mass x gravity Density = Mass /volume Pressure = Force /Area

12. Standard Sea Level pressure is: 1 Atmosphere 14.7 psi 1013 milli bars

13. Air Pressure (& density) drop by 1/2 for every 5.5 km altitude gain.

16. Lapse Rate is the temperature drop per kilometer height increase Typically about 6 °C/km = 6 °C/1000m Or About 3 °F/1000 ft

20. Synoptic Weather map

24. Radio Sonde