## Lab: Ocean Circulation Simulation

### I. Purpose

The purpose of this lab is for you to figure out how to drive ocean circulation. You will also determine how water masses are formed and how currents develop. This will give you insights into the nature of ocean circulation. This lab exercise differs from previous labs because you will decide which materials and methods to use.

### II. Simulating Ocean Circulation

We will provide you with an aquarium where you will simulate ocean circulation. Get together in small groups and decide which materials you will need to complete the following tasks:

1. Drive circulation in the aquarium in three different ways.
2. Form an intermediate and a deep water mass.

Both goals may be accomplished simultaneously.

Sketch and describe what is happening in the aquarium at each step along the way. Sketch the vertical cross section of the flow in the tank. Label the temperature/salt content and the flow direction in each layer. Measure the depths of the thermocline and halocline and label them in the appropriate sketches.

Calculate the horizontal and vertical velocities in each of the three different cases. Include these numbers in your lab report.

### III. Comparison to Real Ocean Conditions

Considering what you know already about the Earth's climate, and what you have seen today in lab, incorporate the answers to these questions in your lab report:

1. Where in the real world do the processes you simulated occur? How do the conditions in the aquarium differ from those found in nature?
2. What steers the currents in the lab experiment? How does that compare with conditions in nature?
3. Which currents were the fastest and which were the slowest? Is this the same as in the real ocean?

### IV. Lab Report Instructions

Write a lab report (as per the Lab Report Format) summarizing the major findings of your investigation.

### V. Optional reading list

• Matisoff, Gerald, Models of Wind-Driven and Thermohaline Ocean Circulation, Journal of Geological Education, 43, 133-137, 1995.
• Dudley, Walter C., A Classroom Demonstration of Thermohaline Circulation, Journal of Geological Education, 32, 175-176, 1984.
• King, Cuchlaine A. M., An Introduction to Oceanography , McGraw Hill, New York, 115-154, 1963.

Updated July 9, 2007
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