Study questions and exercises

Write the answers to the questions in a word document and send it to christian.stranne[at]geo.su.se. Your document should be named with your name and the moment according to the following convention: firstname_lastname_MomentX.docx
Once we received your answers you will get a correction sheet. Correct your own answers using the sheet and where you have questions, please write them in an email to the course email. When you have answered all questions you will also get a code to open the lecture(s) of the next Moment.
The study questions and exercises are only for your own learning and the code system is intended to help you following the course structure and to set your study pace. It is your own responsibility to follow this scheme.

Study questions and exercises on Moment 3

  1. Explain in maximum 5 sentences why the speed of sound central in echo sounding.
  2. Sound velocity decreases with increasing density. Water is almost 1000 times denser than air but still the sound velocity is much larger in water compared to air. Explain why.
  3. What is usually the most important factor causing variations in sound velocity in the ocean?
  4. Assume you have an SVP consisting of seven sound velocity observations (v) at seven depths (z). The maxium depth at the station’s location is 33 m: 
    z = [2 5 10 14 19 22 25];
v = [1479 1478 1474 1460 1457 1455 1454];
    • a) What would the harmonic mean sound velocity be (hint: have a close look at Fig. 2 regarding how each observation of v can be set to represent section of the water column)?
    • b) What would the depth-weighted arithmetic mean sound velocity be?
      Concerning sound speed profiles:
    • a) In a homogeneous ocean (constant salinity and temperature with depth), what shape would the SVP have?
    • b) How would this shape affect the path of a sound pulse from an echo sounder?
  5. Consider the regional SVP variations shown in Fig. 7c in Lecture 1. In single beam echo sounding, what would be the approximate depth error (given as a percentage) if an SVP from the Baltic Sea is used in the Mediterranean Sea. A rough estimate is sufficient.
  6. Explain shortly the, in your opinion, two most important problems with Carter’s Tables.