Lecture12 - Lecture#12 Earth Atmosphere and Climate Earth's...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Lecture #12 Earth: Atmosphere and Climate. – Earth's atmosphere. Earth's atmosphere. – Weather and climate. Weather and climate. Astro 102/104 1 – The greenhouse effect. The greenhouse effect. – Cosmic influences on the biosphere. Cosmic influences on the biosphere. • Reading: Reading: – Chapters 10.1, 10.2, 10.6 Chapters 10.1, 10.2, 10.6 The Main Point The Earth has a relatively thin but d i t h th t th Astro 102/104 2 dynamic atmosphere that warms the surface via the greenhouse effect and makes life possible. Earth's Atmosphere Composition of the Earth’s Atmosphere Gas Symbol Percent PPM Permanent Nitrogen N 78.08 Oxygen O 2 20.95 Argon Ar 0.93 Astro 102/104 3 Neon Ne 0.0018 18 Helium He 0.0005 5 Hydrogen H 2 0.00006 0.6 Xenon Xe 0.000009 0.09 Variable Water Vapor H 2 0 0 to 4 Carbon Dioxide CO 2 .0364 364 Methane CH .00018 1.8 Nitrous Oxide N 2 O .000031 0.31 Ozone (Troposphere) O .000004 0.04 Ozone (Stratosphere) O 3 .0012 12 Particulates .000001 0.01 • Highly oxidizing atmosphere ("Non-Equilibrium"). • Surface pressure: 1 bar (~ 1 kg/cm 2 ). • 1 bar = 10 m of water. • Oceans equivalent to 300 bars! Origin of the Atmosphere Three main possibilities: (1) Primordial: Formed along with the rest of the Earth ~4.6 billion years ago. This hypothesis is hard to reconcile with our current understanding of planet formation. (2) I t l G l d b l i t i th Astro 102/104 4 (2) Internal: Gases released by volcanic outgassing over the history of the Earth. This is likely the main source of atmospheric gases for terrestrial planets. (3) Extraterrestrial: Volatiles (materials that evaporate at relatively low temperatures ) delivered from impacts of icy comets and hydrated asteroids. Evaporation or sublimation of volatiles is another source of atmospheric gas.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern