1. Evolution of the Atmosphere

2. Review of last lecture The modern climatology (meteorology) was born in the 1940s (a very young science!), but has been growing very fast! Now we have a global observational network with many satellites, ships, radars and surface stations, as well as very comprehensive prediction models running on the world ’ s fastest supercomputers.

3. Some basic concepts Units of measurement Scientific notation

4. Standard units of measurement SI (System International) QuantityNameUnitsSymbol Lengthmetermm Masskilogramkgkg Timesecondss TemperatureKelvinKK Densitykilogramkg/m 3 kg/m 3 per cubic meter Speedmeter perm/sm/s second Forcenewtonm.kg/s 2 N PressurepascalN/m 2 Pa EnergyjouleN.mJ PowerwattJ/sW

5. Scientific Notation nanoone-billionth10 -9 0.000000001 microone-millionth10 -6 0.000001 millione-thousandth10 -3 0.001 centione-hundredth10 -2 0.01 decione-tenth10 -1 0.1 dekaten10 1 10 hectoone hundred10 2 100 kiloone thousand10 3 1000 megaone million10 6 1000000 gigaone billion10 9 1000000000 … yotta10 24

6. Video: How the Earth was made? http://www.youtube.com/watch?v=A7m9n gPx5nQ http://www.youtube.com/watch?v=A7m9n gPx5nQ

7. The Universe The Universe is made up of voids and filaments, that can be broken down into superclusters, clusters, galaxy groups, galaxies, and subsequently into stars and their constituents (e.g. our Solar System). Hubble (2012) view – each light speck is a galaxy – some of these are as old as 13.2 billion years – the Universe is estimated to contain 200 billion galaxies.

8. Our Milky Way galaxy Our solar system is in the Orion arm, and we are about 25,000 light years (2.5 X 10 17 miles) from the very center of the Galaxy.

9. Life cycle of the Sun and Earth The earth will be inhabitable for another 0.5 billion years, if we protect it well enough. After another 1 billion years, all oceans and rivers will have completely disappeared. The mean global temperature will reach 160 F.

10. Formation of the Earth 4.6 billion years ago, as part of the birth of the solar system

11. Earth’s first Atmosphere Topic of much debate Probably H and He, no oxygen No oceans No magnetic field to deflect solar winds and cosmic rays

12. Differentiation of the Earth Cooled enough to form crust, heavily populated with volcanoes Formation of magnetic field that deflects the solar wind and cosmic rays Increasing volcano activity, releasing gases into atmosphere

13. Earth’s Second Atmosphere Around 4 - 3.8 billion years ago Composition similar to gases released from volcanoes (CO2, water vapor, nitrogen) Large concentration of gases in the atmosphere (100 times of today’s) Greenhouse effect keeps the earth from freezing

14. Earth Begins to Cool Water condenses to form oceans Carbon Dioxide dissolves into oceans eventually forming carbonates Nitrogen becomes major component of the atmosphere

15. Life and oxygen Around 3.5 billion years ago cyanobateria were known to be carrying out photosynthesis CO2 + H2O + sunlight = organic compounds + O2 Eukaryotes capable of respiration emerge around 2.5 billion years ago. Photosynthesis becomes more efficient Increased oxygen concentration, around 1% of atmosphere, produced the ozone layer Life emerges outside of the oceans. Formation of terrestrial plants lead to atmospheric saturation of oxygen

16. Earth’s third atmosphere (current) Reached around 400 million years ago Consisting of gases, water droplets (clouds/precipitation) and aerosols

17. Formation of the continents and ocean basins 225 million years ago from Pangaea (the super continent)

18. Permanent gases and variable gases Residence time: The amount of time a gas is in the atmosphere The permanent gases: gases having long residence times (N 2 =42,000,000 y, O 2 =5,000 y), 99.999% of total atmosphere mass The variable gases: Gases generally having shorter residence times (H 2 O=10 days, CO 2 =150 y).

19. Importance of the Variable Gases CO2 and water vapor are the major greenhouse gases Water can exist in all three phases (vapor, liquid, ice) on Earth. The released latent heat during phase changes of water drives global atmospheric circulation and many weather systems (e.g. hurricanes). O3 protects us against harmful ultraviolet radiation Montreal Protocol to ban freon

20. Evolution of the atmosphere –The standard units of measurements (SI) –Earth ’ s three atmospheres: 1st: 4.6 billion years ago, H, He Transition: formation of magnetic field, volcano activities 2nd: 4 billion years ago, CO 2, H 2 O, N 2 Transition: emergence of life, formation of ocean 3rd: 400 million years ago, O 2 Important event: formation of seven continents –What is the residence time? What is the difference between the permanent and variable gases? Name 3 of each. What are the most and second most abundant gases? –Given that variable gases are so rare, why are they considered at all? How are CO 2 and O 3 changing?

21. Works cited http://ase.tufts.edu/cosmos/view_picture.asp?id=850 http://www.waterconservation.co.za/2010/10/26/theres -never-been-a-better-time-to-start-harvesting- rainwater/http://www.waterconservation.co.za/2010/10/26/theres -never-been-a-better-time-to-start-harvesting- rainwater/