SO422

Nearshore Oceanography

Fall 2001 Exam 1

Attachment:

Wave equations table

Read all questions carefully.  Full credit on the problems require that your method be clearly identifiable.  For the short answer questions insure that your answer is complete and concise, and covers the key points.  You will be graded by how well you show an understanding of the key concepts of the course.

5 definitions @4               20  ________

Problem                        30  ________

short answers @5, 10 and 20     50  ________

TOTAL                          100  ________

Budget your time.  This exam can be done if you know what you are doing, but do not waste time on a question you do not understand.  On the short answers note that you have some choices on which questions to answer.  Note also that the last short answer is worth 20 points, so you take more care in that answer.

(20) Definitions.  Briefly define 5 of the following terms with no more than a single sentence showing that you clearly understand its importance.  If you use a mathematical relationship, also explain its importance or significance:

·        Dissipative profile:

·        Groin:

·        Orthogonals:

·        Refraction:

·        Shoaling

·        Sorting:

·        SPM or CEM:

(30) A wave has a period T=11.3 sec, and passes a wave gauge in water d=15 m deep. At the gauge H15=5.0 m, and the angle of attack a15=28°.   All calculations on this page use these values, and unless specifically stated you are not to provide answers for deep water.  The bottom slopes uniformly and smoothly offshore. For full credit you must show your method on all questions.  If you cannot solve for something you need, assume a reasonable value and proceed.

(3) For this wave, how deep does the water have to be for it to be considered deep and the wave a deep water wave?

(5) What will be the wavelength of the wave at this depth (not in deep water)?

(2) What will be the speed of the wave at this depth (not in deep water)?

(5) What will be the orientation a0 of the wave in deep water.

(5) What will be the height H0 of the wave in deep water?

(3) Will the wave break before or after reaching this depth?

(3) At what depths will this wave transition from deep to intermediate depth, and from intermediate to shallow?

(4) Answer one of the following questions:

·        At what depth would this wave a speed of 8 m/sec? You may neglect refraction for this answer.

·        At what depth will this wave have its minimum height? You may neglect refraction for this answer.

·        Is there any way the wave could have the same height at two different depths?  You must defend your answer, and may neglect refraction for this answer.

Short Answer.  Answer the following questions as directed with concise, complete answers.  You should use appropriate terminology and concepts.

1.  These two graphs show the variation in a single parameter as two waves come ashore.  Suggest what parameter is depicted, what variable(s) in the wave climate is (are) different for the two waves, and why each graph has the shape it does.

2.  These diagrams show beach profiles measured at Duck, NC, Jan and Aug 1984.  Identify which profile is which, how you could tell, and what causes the difference between the two profiles?

Answer two of the next three questions.  Each is worth 5 points.

3a.  This diagram below shows a portion of the coastline of England.  Discuss what factor or factors control the creation of the Stair Hole, Lulworth Cove, and Mupe-Warbarrow Bay.

3b.  What is the feature depicted by  this diagram, and how does it form.

3c.  What does this diagram depict?  (Use correct terminology, and describe the process involved.)

You  must answer one of the two questions on this page or the next page.  It is worth 20 points.

4a.  This diagram shows the development of a coastal feature(s).  Discuss:

• What is developing;
• The different environments depicted;
• The processes operating.

4b.  This diagram shows four possibilities for a coastal pass.  Discuss:

• What differs in the four cases?
• What is required to keep the pass stationary without building jetties?