Richard B. Rood (Room 2525, SRB) rbrood@umich 734-647-3530 Cell: 301-526-8572

1. AOSS 401Geophysical Fluid Dynamics:Atmospheric DynamicsPrepared: 20131010Climate, Weather, Geography, Earth Richard B. Rood (Room 2525, SRB) rbrood@umich.edu 734-647-3530 Cell: 301-526-8572

2. Class News • Ctools site (AOSS 401 001 F13) • First Examination on October 22, 2013 • Second Examination on December 10, 2013 • Homework posted: • Ctools Assignments tab • Due Thursday October 10, 2013 • Derivations (using notes)

3. Weather • National Weather Service • Model forecasts: • Weather Underground • Model forecasts: • NCAR Research Applications Program

4. Outline • Tour of the Earth • Geography • Planet • Physics

5. Building the Radiative Balance Redistribution by atmosphere, ocean, etc. RS Top of Atmosphere / Edge of Space 1)The absorbed solar energy is converted to terrestrial thermal energy. 2)Then it is redistributed by the atmosphere, ocean, land, ice, life. CLOUD ATMOSPHERE SURFACE

6. After the redistribution of energy, the emission of infrared radiation from the Earth is ~ equal from all latitudes. Because of tilt of Earth, Solar Radiation is absorbed preferentially at the Equator (low latitudes). Another important consideration Latitudinal dependence of heating and cooling Top of Atmosphere / Edge of Space CLOUD ATMOSPHERE SURFACE South Pole (Cooling) Equator (On average heating) North Pole (Cooling)

7. Transfer of heat north and south is an important element of the climate at the Earth’s surface Redistribution by atmosphere, ocean, etc. Top of Atmosphere / Edge of Space This predisposition for parts of the globe to be warm and parts of the globe to be cold means that measuring global warming is difficult. Some parts of the world could, in fact, get cooler because this warm and cool pattern could be changed. CLOUD ATMOSPHERE heat is moved to poles cool is moved towards equator cool is moved towards equator SURFACE This is a transfer. Both ocean and atmosphere are important!

8. Scientific Method • What follows are a series of pictures, plots, graphs – mostly of observations. As we go through them think first • How do I describe the picture? • What type of behavior might be represented? Patterns, correlations • How might I investigate this behavior? • Scientific investigation is based first on observations.

10. Long as I remember the rain been comin’ down [from the National Atlas (1970)] (1930-1961) Grange, October 2006

11. Ocean Surface Currents(From Steven Dutch, U Wisconsin, Green Bay) Good Material at National Earth Science Teachers Association

12. The Thermohaline Circulation (THC)(Global, organized circulation in the ocean)(The “conveyer belt”, “rivers” within the ocean) Blue shading, low salt Green shading, high salt Where there is localized exchange of water between the surface and the deep ocean (convection) Warm, surface currents. Cold, bottom currents.

13. Transfer of heat north and south is an important element of the climate at the Earth’s surface. Redistribution by atmosphere, ocean, etc. Top of Atmosphere / Edge of Space Large scale weather systems transport large quantities of thermal energy from equator toward the poles CLOUD ATMOSPHERE heat is moved to poles cool air moved towards equator cool air moved towards equator SURFACE This is a transfer. Both ocean and atmosphere are important!

14. Tropospheric Mean Meridional Circulation This is not exactly physical, but is a common conceptual model.

15. Dynamic atmosphere: Hurricanes --- Vortices • Satellite image • Storm that originates over warm ocean water • Scale of the motion:1000 km

16. Hurricanes and heatSea Surface Temperature(blue cool / warm orange)

17. Hurricanes and heat

18. Mid-latitude cyclones - waves

19. Mid-latitude cyclones & Heat

20. What goes on vertically?

21. Some basics of the atmosphere Troposphere ------------------ ~ 2 Mountain Troposphere ------------------ ~ 1.6 x 10-3 Earth radius Troposphere: depth ~ 1.0 x 104 m This scale analysis tells us that the troposphere is thin relative to the size of the Earth and that mountains extend half way through the troposphere.

22. An estimate of the January mean temperature note where the horizontal temperature gradients are large mesosphere stratopause stratosphere tropopause troposphere south summer north winter

23. An estimate of the January mean zonal wind note the jet streams south summer north winter

24. An estimate of the July mean zonal wind note the jet streams south winter north summer

25. Let’s spend some time with the atmosphere. • Start with a typical upper tropospheric chart. • What is a good estimate of the pressure at the surface? • What is a good estimate of the pressure in the upper troposphere? • How could you figure out the geometric height?

26. Geostrophic wind 300 hPa How does this example relate to global scales?

27. 300 hPa

28. Geopotential contours at 300 hPA Northern Hemisphere September 17, 2008

29. Wind and geopotential 200 hPa Note: Variability in east-west of the wind field. Note: Time variability of the wind field. Note: Troughs associated with mountain ranges, continents

30. Geopotential contours at 850 hPa Northern Hemisphere September 17, 2008

31. 700 hPa

32. 500 hPa

33. 300 hPa

34. 50 hPa

35. North-south / Winter-summer

36. DJF 500 hPaAverage

37. JJA 500 hPaAverage

38. Anomaly 100 hPa

39. 23 October 2006, Geopotential Height

40. 23 October 2006, Ozone

41. Take Away Points • The details of the Earth’s relation to the Sun, energy received, tilt of axis, variations in orbit set up gradients of temperature (energy) in a fluid (atmosphere and ocean), and the fluid moves to reduce these gradients. • Composition of atmosphere and ocean important to the energy distribution • The distribution of land and water, mountains, plants, etc. are fundamental to climate and weather. • The rotation of the Earth is a defining characteristic of the motions of the atmosphere and ocean.

42. Take Away Points • Motion in the atmosphere and ocean is often described as types of features – notably: • Waves • Vortices • We can “isolate” and study; diagnose balances of momentum, mass, and energy; predict behavior of these features with significant skill • The interactions between all of these “isolated” features is far more difficult to study quantitatively and at the center of how energy is ultimately re-distributed.

43. Summary of Take Away Points • The patterns of weather and climate that we see are not random or accidental. • Basic redistribution of energy • Determined by characteristics of Earth – especially relation of Earth to Sun and rotation • Determined by geography • Determined by surface energy characteristics • Chaos?