Oceanography Questions

E4) Exercise #4: Exploring Coastal Upwelling

Goals

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Understand how scientists report direction in compass points, azimuth bearings, and quadrant bearings.

Investigate the relationship between winds, surface currents, sea surface temperature and upwelling and

downwelling.
• Determine if upwelling or downwelling was occuring along the Pacific Northwest coast in September of 2013.

Background

Seasonal upwelling is a very important process not just to the Pacific Northwest but to many coastal regions in the world. During the summer in the Northern Hemisphere, upwelling is driven by winds blowing from the North to the South (Northerlies) that, combined with the Coriolis Effect, push surface water off-shore and out to sea.

Upwelling pulls deep ocean water up to the surface making the surface coastal ocean more salty, cold, and nutrient rich. The added nutrients in the sunny surface waters trigger fast phytoplankton growth and reproduction, which is the base of the food web and supports the important fisheries along the West Coast of the US.

Background Knowledge

To measure and report relative directions on Earth, scientists use compass points, azimuth bearings, and quadrant bearings. This measurement system measures horizontal directions, as if you were in the air looking down at a flat surface. Take a few minutes to review these resources on compass points, azimuth bearings, and quadrant bearings:

Thinking in Circles (http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/comp.html).

Section: Points of a Compass (http://gwydir.demon.co.uk/jo/units/angles.htm#compass)

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The figure below summarizes these three systems by giving the location of the red star using each system.

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Compass point: SE Azimuth Bearing: 140° Bearing: S40°E
(E4) Exercise #4 – Page 1 of 10

Once you understand the difference between the three systems (compass points, azimuth bearings, and quandrant

bearings), complete the exercise below.

On the drawing of a compass to the right, assume that “A” is zero degrees. List the compass point, azimuth bearing, and quandrant bearing of letters V, W, X, Y, and Z.

W

A
Y

X

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Compass Azimuth Quandrant Point Bearing Bearing

V

______________ ______________ ______________ Z

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1) V.
2) W.
3) X.
4) Y.
5) Z. ______________ ______________ ______________

______________ ______________ ______________ ______________ ______________ ______________ ______________ ______________ ______________

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If you think you understand compass directions, you may go on to the next part of this exercise

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The Exercise

Our overall goal for this exercise is to answer the question: In late September 2013, was upwelling occurring on the Pacific Northwest coast?

We will review indicators of upwelling using data from NOAA. We will then synthesize those indicators to decide if upwelling is occurring. Questions that you will answer in Tests & Surveys for this exercise are numbered below and indicated in bold, italicized text below.

Columbia River

Stonewall Bank Port St Georges

California

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We will review several data sources for this exercise. We will review data from September 2013 for three NOAA buoy stations: Stonewall Bank, Port St Georges, and the Columbia River Bar. The approximate location of these buoys is highlighted on the map to the right. For your convenience, the buoy data you will use is included at the end of this exercise. You do not have to visit the links above for this exercise, unless you are interested in seeing the data sources.

Washington

Oregon

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We will also review maps of ocean current direction off the coast of Oregon. The data you will review is from this site: Surface Currents Of The Oregon Coastal Ocean. For your convenience, the map you will use is included at the end of this exercise. You do not have to visit the links above for this exercise, unless you are interested in seeing the data sources.