1. Ocean and Sun AP Env Sci 2011-2012

2. Global Winds and Ocean Currents The source of this material is the Digital Library for Earth System Education website at http://www.dlese.org. All Rights Reserved."http://www.dlese.org Source: NOAA

3. The Gulf Stream Source: NASA

4. The Gulf Stream East Coast United States, officially discovered by Benjamin Franklin, mapped and published in 1770 Strengthened and directed by the Westerlies Moves North and East –North Atlantic Drift: Keeps Britain and NE Europe warmer than predicted by latitude.

5. Thermohaline Circulation Thermo = temperature Haline = salinity Colder, higher salinity water sinks (more dense) Source: NOAA

6. Why are Ocean Currents Important? Navigation Moderating Climates (ie., Great Britain) Maintain Earth’s Heat Balance –Move heat from Tropics to Poles –About ¼ of Earth’s total heat movement

7. Upwelling and El Nino http://www.youtube.com/watch?v=uySu7Zv2cbU http://www.montereyinstitute.org/noaa/less on08.htmlhttp://www.montereyinstitute.org/noaa/less on08.html

8. Sun – The Source of Earth’s Energy What Happens to the Incoming Energy? Source: www.noaa.gov

9. Fate of Incoming Solar Energy Reflected: 31% of Total Scattered Into Space by Atmosphere: 8% Reflected by Clouds: 17% Reflected by Earth’s Surface: 6% Absorbed: 69% of Total Absorbed by Gases (water vapor, dust, ozone) 19% Absorbed by Clouds 4% Absorbed by Earth’s Surface 46% What Determines Whether Energy is Reflected or Absorbed? Wavelength!

10. “Short” wavelength radiation (0.3 to 0.7 um wavelength) makes up a large fraction of Sun’s radiation. This energy passes readily through the Atmosphere. This is visible light Major absorber @ UV (short) wavelength: Oxygen/Ozone 0.2-2 um Not Nitrogen Source: NOAA

11. Reflectivity of Earth’s Surfaces Albedo: Fraction of total radiation reflected by a surface. Average for Earth (solid, liquid, gas) is about 30% SurfacePercent Reflected Fresh snow80-85 Old snow50-60 Sand20-30 Grass20-25 Dry earth15-25 Wet earth10 Forest5-10 Water (Sun low)50-80 Water (Sun high)3-5 Thick cloud70-80 Thin cloud25-30

12. Fate of Radiation Absorbed by Surface About 50% of total energy from Sun is absorbed – this must be “lost” or Earth will HEAT UP! Where it goes: –About 7% heat transported from Earth’s surface to atmosphere by conduction and convection –About 23% heat transported upward by evaporation –About 21% lost by long wavelength (IR) radiation from Earth’s surface All of this is eventually lost to space by long wavelength (IR) radiation from atmosphere

13. The Whole Picture Source: www.noaa.gov

14. Greenhouse Gas Intro On previous slide, long wavelength energy (IR/heat) is transferred from Earth to atmosphere. We learned that UV/visible light is absorbed by O2/O3 Greenhouse gases absorb long wavelength (IR) energy and re-radiate some back to Earth’s surface. Some heat is “trapped” in the troposphere and Earth’s surface. Aside: Interestingly, although this is called the “Greenhouse Effect” it is not actually how greenhouses work.