SO231 GENERAL OCEANOGRAPHY

COURSE OBJECTIVES (8/2000)

2. History, mapping the oceans OBS&E p.5-13

A. Relate the contributions of the Wilkes expedition, the Jeannette, Fram, and Challenger to the development of oceanography.

B. Describe the relationship of accurate navigational methods to scientific oceanography.

C. Discuss the importance of accurate depth measures to scientific oceanography.

3. Ocean floors OBS&E p.13-25

A. Discuss the importance of the maps of Maury to the development of oceanography.

B. Discuss the operation of swath bathymetry echo-sounders and side scan sonar sensors.

C. Differentiate the geoid and ellipsoid.

D. Describe how gravity correlates with bathymetric features.

E. Describe how satellite altimeters provide useful oceanographic data.

F. Discuss the history of ocean drilling (DSDP and ODP) and submersible research.

4. Continental margins & ridges OBS&E p.26-38

A. Differentiate oceanic and continental crust; lithosphere and asthenosphere; crust, mantle, and core.

B. Describe the processes at spreading axes and subduction zones.

C. Describe the formation and importance of the magnetic stripes on the sea floor.

D. Differentiate active and passive (seismic/aseismic) continental margins.

E. Discuss the continental shelf, break, slope, rise in terms of their slopes and typical depths.

F. Describe island arcs and back-arc basins.

G. Describe ridge morphology.

H. Understand the age-depth relationship across ridges.

I. Key term: isostasy.

5. Transforms and abyssal plains OBS&E p.38-45

A. Discuss conservative plate boundaries, and know two examples.

B. Differentiate transform faults and fracture zones.

C. Discuss the major characteristics of the abyssal plains, seamounts, guyots, and aseismic ridges.

D. Relate hot spots to the formation of Emperor seamounts and the Hawaiian islands.

6. Satellite bathymetry case study OBS&E p.45-53

A. Discuss the relation of geoid anomalies to marine bathymetry and spreading patterns.

B. Understand limitations on the use of satellite determinations of the geoid.

C. Describe how more recent altimeters have improved our knowledge of the ocean floors.

7. Birth of an ocean OBS&E p.55-61

A. Know the age of the earth (4.5 BY) and the oldest seafloor left in the oceans (<200 MY).

B. Describe the stages in the evolution of an ocean basin.

C. Describe the Red Sea as an example for the creation of an ocean basin.

D. Key term: evaporite.

8. Major ocean basins OBS&E p.62-67

A. Describe the locations of major ridges and trenches in the world's oceans.

B. Describe complexities in histories of the Pacific and Indian Oceans as compared to the Atlantic.

C. Describe the Mediterranean as an example of an ocean in the final stage of its life.

D. Key terms: ophiolites.

9. Water, air, and ice SCP&B p.4-13

A. Describe the anomalous properties of water resulting from its hydrogen bonds and their effect on climate and the oceans, especially latent heat and heat capacity.

B. Describe the effect salinity has on the freezing of water, and the importance of a salinity about 25.

C. Differentiate sea ice and icebergs, and the difference in icebergs in the two hemispheres.

D. Key terms: residence time.

10. Temperature in oceans SCP&B p.14-28

A. Discuss transfer of energy across the air-ocean interface.

B. Know the three layers of the ocean.

C. Describe variation of temperature with depth at various latitudes.

D. Discuss different thermoclines (daily, seasonal, main) and their movement with time.

E. Key terms: insolation, albedo, greenhouse effect, equinoxes, solstices

11. Salinity in oceans SCP&B p.29-38

A. Know the average salinity of the oceans (35 PSU), its units, and how it is normally written.

B. Know the six major ions in seawater.

C. Discuss the law of constancy of composition, and the exceptions to the generalization.

D. Discuss the variation in surface salinity and salinity with depth profiles throughout the oceans.

E. Discuss methods of measuring salinity, and the formal definition of salinity as a ratio.

F. Key terms: brackish, hypersaline, anoxic, anaerobic

12. Density and pressure in oceans SCP&B p.39-49

A. Differentiate potential and in situ temperature, and potential density (sigma-theta).

B. Calculate sigma-t, plot it on a T-S diagram, and discuss the uses of the T-S diagram.

C. Differentiate conservative and non-conservative properties of water.

D. Key terms: water masses, adiabatic, hydrostatic equation, pycnocline

13. Mixing in oceans SCP&B p.49-56

A. Differentiate molecular diffusion and turbulent mixing.

B. Describe how oceanic microstructure might form by salt fingering or breaking of internal waves.

C. Discuss fronts and isopycnal surfaces.

14. Underwater light SCP&B p.61-72

A. Describe light attenuation from absorption and scattering.

B. Discuss controls on the depth of photic and aphotic zones.

C. Discuss how light affects underwater vision.

D. Describe how transmissometers, irradiance meters, and the Secchi disk work.

E. Discuss why seawater has the colors it does.

15. Underwater sound SCP&B p.72-84

A. Discuss the loss of acoustic intensity due to spreading loss and attenuation.

B. Describe the relationship of sound velocity to temperature, salinity, and pressure.

C. Sketch typical profiles of sound velocity, and describe the controls on the different portions of the profile.

D. Know a typical value for the velocity of sound in the ocean.

E. Key terms: sound channel, shadow zone, refraction, SONAR, scattering layers, SOFAR

17. Radiation balance OC p.6-12

A. Describe the two mechanisms for ocean circulation and their source of energy.

B. Discuss the Coriolis force and its application to ocean circulation.

C. Describe the variation of the energy balance with latitude.

D. Key term: advection.

18. Atmosphere and ocean OC p.13-29

A. Sketch the global pattern of winds in the three cell model.

B. Discuss vertical convection in the atmosphere.

C. Discuss the development of tropical cyclones.

D. Key terms: Hadley cell, ITCZ, cyclones and anticyclones, adiabatic

19. Wind and inertia OC p.31-40

A. Describe wind stress, and molecular and eddy viscosity.

B. Discuss Ekman motion and the Ekman spiral.

C. Describe the parameters that control the Coriolis force.

D. Discuss inertia currents.

20. Geostrophic currents OC p.40-59

A. Describe the geostrophic currents created by the horizontal pressure gradient force.

B. Understand hydrostatic pressure and horizontal pressure gradients.

C. Given density (temperature and salinity) distributions, determine how the sea would slope and the resulting geostrophic currents.

D. Key terms: isobaric, isopycnic, barotropic, baroclinic, gradient equation, dynamic topography, geoid

21. Divergence, convergence, eddy OC p.59-69

A. Describe the kinetic energy density spectrum of the ocean.

B. Describe the role of mesoscale eddies in the circulation of the ocean.

C. Describe the effects of wind on the vertical motion of water.

D. Key terms: divergence, convergence, upwelling, Ekman pumping, gyres, fronts, Langmuir circulation

22. Subtropical gyres OC p.79-96

A. Describe a typical gyre and its eastern and western boundary currents.

B. Describe the relationship between vorticity and the Coriolis Force.

C. Differentiate relative, planetary, and absolute vorticity.

D. Describe how conservation of vorticity leads to topographic steering.

E. Describe western intensification and why the Gulf Stream forms.

F. Discuss the use of the equations of motion and the principle of continuity.

23. Gulf Stream OC p.73-79, OC p.96-119

A. Discuss geostrophic flow in the Gulf Stream, and the importance of conservation of vorticity.

B. Differentiate Lagrangian and Eulerian methods for studying currents.

C. Describe water characteristics within the Gulf Stream and their use in tracking the formation and evolution of eddies.

D. Describe the reasons for coastal upwelling in eastern boundary currents.

24. Equatorial currents OC p.122-134

A. Describe the currents, undercurrents, divergences, and convergences found at the equator.

B. Describe why upwelling occurs at low latitudes.

C. Locate the following currents: North Equatorial, South Equatorial, Equatorial Counter

25. Monsoon, long waves OC p.134-145

A. Describe the climatic reasons for the developments of monsoons in the northern Indian Ocean.

B. Describe seasonal circulation in the Indian Ocean, and why this differs from a typical ocean gyre.

C. Discuss the role of long Kelvin and Rossby waves in oceanic circulation.

D. Key terms: amphidromic systems, wave guides

26. El Niño, high latitudes OC p.145-155

A. Describe what happens in the atmosphere and oceans during an El Niño event.

B. Discuss differences in circulation in the Arctic Sea and around Antarctica, and the reasons for this difference.

C. Describe the circulation pattern around Antarctica.

D. Key term: West Wind Drift (Antarctic Circumpolar Drift).

27. Ocean heat budget OC p.159-168

A. Describe the reasons for the variation in insolation with latitude.

B. Write the heat budget equation for the oceans, and know the relative importance of the major losses.

C. Key terms: Bowen's ratio, albedo

28. Salt conservation, water masses OC p.168-185

A. Describe the variation in surface salinity in the world's oceans, and the reasons for the patterns.

B. Characterize upper, intermediate, deep, and bottom water masses.

C. Describe where and why the deep and bottom water masses form.

D. Key terms: residence time, conservative and non-conservative properties, mode water, common water.

29. Mixing and T-S diagrams OC p.185-195

A. Describe how to find a water mass on a T-S diagram, and how to calculate mixing of water masses.

B. Key terms: salt fingering, core water, stability, cabelling, potential vorticity

31. Tracers and global fluxes OC p.195-204

A. Discuss the use of natural and artificial tracers in the oceans.

B. Describe the global fluxes of heat and freshwater within the oceans.

32. Waves and wave forms WT&SWP p.11-18

A. Discuss the controls on a fully developed sea: fetch, duration, and wind speed.

B. Discuss the types of waves.

C. Key terms: wave height, amplitude, steepness, period, frequency, progressive and standing waves, surface and internal waves, capillary and gravity waves, significant wave height, wave speed, Beaufort Scale

33. Wave Theory & Equation p.18-26

A. Use the deep and shallow water approximations to the wave equation, and verify that the governing assumptions are valid.

B. Discuss the motion of water particles in surface wave theory.

34. Wave energy WT&SWP p.26-37

A. Discuss wave dispersion and group speed.

B. Describe the variations in wave energy, wave height, and wave speed in shallow water.

C. Describe the characteristics of the different types of breakers, and the beach conditions that favor each.

D. Key terms: swell, attenuation, refraction.

35. Unusual waves WT&SWP p.38-46

A. Describe the interactions of waves and currents, and the occasions under which giant waves can form.

B. Discuss the characteristics of tsunamis.

C. Calculate the period of a seiche in both open and closed basins, relating period to basin geometry.

D. Key terms: node, antinode, resonant period.

36. Tide basics WT&SWP p.50-61

A. Describe the balance of forces between gravity and the centrifugal force that creates the tides.

B. Discuss the equilibrium theory of the tides developed by Newton.

C. Describe the effect of the moon's declination, the moon's apogee and perigee, the sun's aphelion and perihelion, quadrature and syzygy, on the tides.

37. Tide theory WT&SWP p.62-72

D. Discuss the reasons for the breakdown of the equilibrium theory of the tides, and how the dynamic theory of the tides offers an improvement.

E. Describe the development of an amphidromic system.

F. Discuss the harmonic method to predict tides using partial tides.

G. Key terms: ebb, flow, tractive force, spring and neap tides, indirect and direct tides, Kelvin wave

37.Real tides WT&SWP p.72-84

A. Describe how variations in the diurnal inequality lead to diurnal, semidurnal, and mixed tides.

B. Discuss some of the complexities of tides in shallow bodies of water.

C. Describe how storm surges can complicate tide predictions.

D. Discuss tides in rivers and estuaries, and the development of tidal bores.

39. Beaches and littoral zone WT&SWP p. 125-132,141-142

A. Describe the main parts of a beach profile.

B. Describe the development of longshore and rip currents.

C. Relate beach profiles to grain size, wave type, and beach materials.

D. Describe the seasonal beach profiles that develop along beaches of the U.S. East Coast.

40. Estuaries WT&SWP p149-150,155-165

A. Classify estuaries based on mixing.

B. Describe sedimentation in the different estuaries.

C. Key terms: null point, flocculation.

41. Changes in sea level OBS&E p.120-124,134-137.

A. Describe the effects on sea level of the volume of water in the oceans and the size of the ocean basins.

B. Know the effect of changing pressure (1 mbar = 1 cm) and temperature (1°C = 0.8 m) on sea level.

C. Discuss the post-glacial rise of sea level, including the local effects of isostasy.

D. Discuss the impact of plate spreading on sea level.

Overall Lab objectives:

a. Reinforce key points from the lectures and course texts.

b. Conduct repeated measurements at two stations (shallow and deep) with the CSTD (including transmissometer and dissolved oxygen), photometer, sound velocimeter, Secchi disk, and Forel scale. Relate trends in measured parameters to oceanographic processes in the Bay.

c. In small groups (1-2 mids), prepare part of a poster (1-2 graphs and a paragraph of text) or a web page showing how and why a single oceanographic parameter varies over the course of the semester. Appropriate parameters include: (1) Temperature, (2) salinity, (3) light extinction coefficient, (4) secchi disk and Forel scale, (5) dissolved oxygen, (6) transmissivity, (7) natural fluorescence, and (8) density

d. Prepare a 5 page paper, based on primary scientific references (journal, monograph, or edited volumes), on some aspect of the Chesapeake Bay, which could be related to the parameter above.

Specific SO231 Lab Objectives:

Introduction to oceanographic instrumentation (YP)

a. Understand the principles of operation of: CSTD/CTD, photometer, fluorometer, GPS navigation, echosounder, Secchi disk, and Forel scale.

b. Take readings at shallow and deep stations.

Sidescan SONAR

a. Describe operation of a side scan SONAR system, and the information it provides.

b. Create a bathymetric profile across the thalweg of the old Susquehanna River.

Sound and light.

a. Compare the results of different light meters and transmissometers.

b. Compare calculated and measured sound velocity profiles.

c. Calculate the extinction coefficient for light.

Geologic data collection (YP).

a. Take bottom samples using appropriate sampling devices.

E-W or N-S T-S profiles in Chesapeake (YP)

a. Using a series of CSTD casts, construct a profile in the either N-S direction (to show the salt wedge) or the E-S direction (to look for Coriolis effect).

Library-introduction to oceanographic research.

a. Know tools available for obtaining references at Nimitz Library: CD's, indexes, interlibrary loan.

b. Differentiate a scientific paper (journal article) from a magazine news article, even when both occur in the same periodical (e.g. Science).

c. Understand the importance of abstracts for journal articles and conference presentations.

d. Understand why scientists present papers and poster sessions at conferences.

Bathymetry-gravity-magnetics computer lab using the Marine Geophysics Trainer.

a. Understand gravity and magnetic anomalies, and the reasons they occur.

b. Relate gravity anomalies to major bathymetric features: trenches, ridges, transform faults, fracture zones, and seamounts.

c. Develop an appreciation for what the sea floor looks like.

GLORIA and GEOSAT.

a. Describe the operation of side scan sonar imaging systems and interpret imagery.

b. Describe how a radar altimeter works and interpret altimeter records of the marine geoid.

T-S diagrams.

a. Describe temperature and salinity versus depth profiles, and T-S diagrams, for the equator, tropics, mid latitudes, and polar regions, in both summer and winter.

b. Describe the location of the sound channel, and how it varies with latitude.

Geostrophic Currents

a. Calculate the geostrophic current from density versus depth data.

b. Use a T-S diagram to discuss the mixing of water masses.

Geostrophic Currents

a. Look at currents throughout the world and interpret them as geostrophic.

Tide record analysis

a. Look at a series of tide records, and be able to differentiate diurnal, mixed, and semidirunal tides; the tide range and diurnal inequality; neap and spring tides.

b. Compare predicted and observed tide records for Annapolis.

Seasonal Bay presentations

a. Present a short summary of the term paper.

b. Describe how and why one oceanographic parameter varies over the course of the semester.

Oceanography Geography

You will be responsible for locating these locations on a world map; given the name, you must locate it on the map, or given a location on the map, you must name the feature located there.