Fieldtrip #2 –Alternate Option Assignment to Blacks Beach Fieldtrip: Ocean Swell and Surface Currents Assignment Worksheet

This alternative to the in-person fieldtrip focuses on ocean swell and surface currents, and is to be completed online.

This assignment has two parts: 1) Interpreting swell models for offshore Southern California; and 2) Surface currents of the world ocean. Students need to click on the listed links to view and study charts and videos that describe and explain swell models and surface currents. Afterwards, the student needs to answer a set of questions.

PART I. CDIP SWELL MODELS OF SOUTHERN CALIFORNIA

Directions: The following set of ocean swell exercises below were put together by Dr. Chris Metzler at MiraCosta College, and can be found at this Palomar College URL:

http://www.palomar.edu/oceanography/waves/index.htm

Below are 16 questions that pertain to the online ocean wave exercises found at the above URL. The questions are arranged according to the different exercise topics listed on the exercise outline - each topic has its own set of charts, images, and information – starting at the Introduction and ending with Current Conditions. Note that a couple of the topics are skipped because they are pretty much redundant exercises.

Introduction - Exercise #2 Questions

1) What is the water depth of the buoy that measures the swell?

2) For swell from the N-NW, what is the lag time for a swell reaching San Diego after being measured at the platform?

The Southern California Swell Prediction - Northwest Swell - NW Swell - Exercise #3 Questions

Notice the high waves along the northwest sides of some of the offshore islands.  

3) How large are these waves? (Please indicate the height in feet.)

4) Why are the waves so large in these locations? (Refer back to the introduction if you need to.)

Now examine the California coastline (not the islands). 

5) What is the approximate latitude and longitude of the area where the highest waves are predicted to occur?

6) How large are those waves?

Southern California Coastal Wave Height - Exercise #4 Questions

7) Where are the swells highest?  

8) Give the height (in feet) for the predicted swell. (Hint: give a range of heights.)

9) How do you explain the swell being highest in that location?  (Note: you may want to refer back to the previous image in order to answer this question.)

Southern California Swell Prediction - South Swell - Exercise #7 Questions

Compare the size, direction and period of the 25 JUL 96 south swell to the 3 DEC 95 north swell which we viewed earlier in this assignment, and describe where the waves are larger during the south swell, and where they are smaller compared to the data set we viewed for the 3 DEC 95 north swell. Notice the area of large wave size near 32.5 degrees north, 119 degrees west (indicated with arrows on the image).  These areas of large swell are immediately northeast of shallow areas of the seafloor known as Cortes Bank and Bishop Rock. Also, notice the difference between the two swells, in terms of the areas where there are little to no swells (Hint: effects from Pt Conception and landward sides of the islands).

10) How do you explain the areas of high swell along southern California's mainland coastline from the 25 JUL 96 south swell?  (Note: you may want to return to the Introduction to refresh your memory.)

11) Why don't these areas show high waves during the 3 DEC 95 north swell (in the lab introduction)?

Southern California Swell Prediction - Two Swells - Exercise #8 Questions

12) Describe how the swells on this date are different from the images we saw earlier.

Current Conditions - Exercise #10 Questions

13) What is the date and time of the swell prediction?

14) What is (or are) the swell direction(s), period(s) and heights?

15) Where along the shoreline are the swells expected to be largest (give the latitude and longitude)? How large are the swells expected to be?

16) Based on the predicted swell, will there be good surfing in the San Diego area? Why or why not?

PART II. CURRENTS OF THE WORLD OCEAN

Directions: The educational video covering the various types of ocean currents for this exercise was put together by the NOAA, and can be found at this the Monterey Institute URL:

http://www.montereyinstitute.org/noaa/lesson08.html

Below are 14 questions that pertain to the online ocean waves exercise found at the above URL. The questions are arranged according to the different exercise topics listed on the exercise outline - each topic has its own set of charts, images, and information – starting at the Introduction and ending with Current Conditions. Note that a couple of the topics are skipped because they are pretty much redundant exercises.

Ocean Currents Exercise Questions:

1) What are the three major forces that cause ocean currents?

2) What are the two distinct current systems in the ocean?

3) What is four-letter name for the major circular surface currents found in each ocean basin? How many of these are there?

4) What is the most important cause of surface currents? And the second most important cause of surface currents?

5) The spinning Earth has an effect on the surface currents. What is this effect called and why does it occur?

6) Surface waters deflect in which direction in the northern hemisphere due to the spinning Earth?

7) Compare and contrast the western boundary currents from eastern boundary currents.

8) What causes longshore currents to form? What are their effects on the shoreline?

9) What causes rip currents to form? What are their effects on the shoreline?

10) What causes upwelling currents to form? What are their effects on the shoreline?

12) What is an important surface process helps drive the deep ocean's thermohaline (density) circulation?

13) What is the "Global Conveyor Belt" global ocean circulation?

14) What are the important effects on the GCB on Earth's climate?