Assignment

How are tides affected by their location? Which types of tides are found in the United States? What causes that pattern?

There are two acceptable methods for completing the project, one using Excel and one using a manual approach that does not require Excel. Please read the instructions carefully. It is possible to do this project without using Excel if you do all of the calculations and graphing by hand.

NOAA data sets from widely-separated tide stations are included. The data were obtained from the National Oceanic Survey of NOAA web site.

The data sets cover hourly water level values over a one-month period from January 1 through January 31, 2009. As the data header shows, the times are Greenwich Mean Time (GMT), not local time, and the water levels are in feet.

Compare tidal information from the following sites:

•Anchorage, Alaska
•New London, Connecticut
•Key West, Florida
•Eagle Point, Texas

For each of the sites above, click on the link to open the file of data. After it opens, choose "Save Page As" (which is under File menu), then save the file to a folder on your hard drive or flash drive. Repeat this process for each of the text files.

In your comparison, include a comparison of the sites over the 31-day period. Also include a comparison over a smaller time scale of 4 to 10 days. This shorter duration will allow you to see the tidal fluctuations in more detail. Your comparison should also relate to the phases of the moon for the period covered by the data, in other words, how are the phases of the moon and tidal waves related? Your comparison should include graphs using the exact same vertical scale (water level range) so that you can see the difference in tidal range between stations. It may include graphing all four sites on the same graph or on four separate graphs that are aligned by time.

Discuss the type of tide at each location and the comparison including relative height, tide type, and time differences of high tides.

Instructions (Using Excel):

Using the Guam tidal data as a sample, follow these instructions for importing tidal data into Excel.

Guam Tidal Data
Importing Tidal Data

Once you are comfortable with importing tidal data into Excel, you can follow the same procedure for the other four data sets. You are graphing a 31-day period and a shorter (4- to 10-day period) for each of the four locations. Remember, to graph a shorter period, you must first select a smaller range of data.

Instructions (Without Excel):

Plot graphs of each of the stations over the 31-day period and the shorter 4- to 10-day period as outlined above.

Plan out your whole set of graphs before you start so you don't have to redo them because of poor scale choices. Use graph paper or grid paper.

When plotting the longer interval, you don't need to plot every hourly point; just plot about every three hours unless there is a maximum or minimum point in between these points. Include all four sites on the same graph or on four separate graphs that are aligned by time. Clearly label the graphs and scales.

Discuss the type of tide at each location and the comparison including relative height, tide type, and time differences of high tides and the phases of the moon (if you can find them).