Sea Surface Temperature Trends of the Gulf Stream

Weekly Sea Surface Temperature, January 1997

Image courtesy MY NASA DATA Live Access Server. Weekly Sea Surface Temperature, January 1997

Students will use authentic satellite data to explore the seasonal changes in sea surface temperature of the Gulf Stream.
Grade Level: 6 – 12
Estimated Time for Completing Activity: One 50-minute class period
Learning Outcomes:
  • Students will be able to understand and explain the importance of the Gulf Stream
  • Students will be able to explore real satellite data and construct graphs for analysis
  • Familiarity with accessing websites on the Internet
  • Familiarity with locating geographical positions on a map
  • Familiarity with producing graphs in Excel
  • Computer with Internet access
  • Spreadsheet program
  • Atlas or Globe
AP Environmental Science Topics
Lesson Links:

Intense incoming solar radiation of the Sun is continuously entering into the vast tropical oceans of the Earth. The energy enters these water bodies at the surface when absorbed radiation is converted into heat energy. The warmed surface water is then transferred downward by conduction and convection to form a mixed surface layer of increased temperature. The horizontal transfer (balance) of this heat energy from the Equator to the poles is accomplished by ocean currents.

One of the most studied and important ocean currents of the world lies along the eastern coast of the United States and is called the Gulf Stream. It derives its name from its source region of warm water in the Gulf of Mexico. The Gulf Stream transports enormous amounts of heat from the Gulf of Mexico northward along the East Coast, and then northeastward toward Europe. Along the way, it warms the overlying atmosphere, transferring much of its heat energy through the process of evaporation. The latent heat energy (released as the warm air rises and condenses) can fuel interesting weather events such as East Coast snowstorms and hurricanes, and provide milder winters for the high latitudes of Europe.

The evaporative process also causes the cooling surface waters arriving in the North Atlantic to become increasingly salty and dense enough to sink. The water then flows back southward toward the tropics along the bottom of the Atlantic Basin. This overturning is part of a global pattern of ocean circulation driven by winds and the exchange of heat and water vapor at the sea surface. It is believed that any small changes to this circulation will have significant effects on global climate.

For the past two decades, scientists have been collecting sea surface temperature (SST) data from satellites, buoys and ships in the Gulf Stream and Atlantic Basin. In this lesson, you will gain access to the data used to monitor these weather and climate effects. The data that is used in this lesson is from the Group for High Resolution Sea Surface Temperature (GHRSST), and is an international activity that orchestrates a wide variety of input and output data from a wide variety of missions, sensors, instruments and satellites. The data are shared, indexed, processed, quality controlled, analyzed and documented within an international framework. The group aims to provide the best quality sea surface temperature data for applications in short, medium decadal and climate time scales. Large volumes of data and associated data services are harnessed together to deliver the new generation of global coverage high resolution SST data sets. The GHRSST group is still active and producing data sets.


Pre-lesson inquiry activity: Have students write hypotheses about (1) the effects of the Gulf Stream on coastal water temperatures and (2) the effects of the gulf Stream on the fishing industry.

Part I: Students will explore the Live Access Server (LAS) and produce plots of sea surface temperature. An example plot of SST for the Gulf Stream is provided above.

1. Click on the link above to access the Live Access Server.
2. If not automatically prompted, click on Choose Dataset and then select, Oceans, Daily Sea Surface Temperature (GHRSST).
3. On the map to the right, draw a box around the geographical region of the Gulf Stream using a click and drag if the mouse, or enter latitude and longitude coordinates in the text boxes to the right of the map. The approximate domain of interest is 85 to 40 West longitude, and 15 to 52 North Latitude.
4. Select the time you wish to explore. Click update Plot at the top left corner of the page to see your color plot.
5. Repeat step 4, choosing different months, to explore seasonal changes in the Gulf Stream sea surface temperature.

Part II: Students will prepare a time series of data for particular location(s) on the Gulf Stream.

1. From the menu to on the left under Line Plots, choose Time.
2. Using the map in the upper left corner, click on the circle tool above the navigation map and select a location over the Gulf Stream. A yellow dot will indicate your selected latitude and longitude. You may also enter your coordinates into the latitude-longitude text boxes to the right of the map. If you are having a hard time selecting a location, you can use the magnifying glass buttons to zoom in or out to better choose your location.
3. Under time range, select one year of data (January 1, XXXX – December 31, XXXX), then click on the Update Plot Button in the upper left. You can also check the box for the plot to update automatically.
4. From the tool bar at the top choose Show Values, then click OK.
5. Select All, then copy these data and paste into a file on your Desktop.

Part III: Students will use Excel to produce and analyze graphs of sea surface temperature. An example Excel file is provided above.

1. Open the data file(s) with Excel, or open Excel and import your table(s) of values.
2. Highlight the cells which contain the date and temperature information.
3. Under the Insert menu, click Chart.
4. For Chart Type, highlight Line, click Next.
5. Choose your line preference, click Next.
6. Verify that your temperature data appears as Series 1. If you have multiple locations, each should be an individual series on the chart.
7. Type in Sea Surface Temperature for Gulf Stream for the title. Type in Temperature C for Value (Y) axis, Date for Value (X) axis. Click Next.
8. Select As new sheet, click finish. This places the graph on another spreadsheet. If you want the graph on the same spreadsheet as the data, you change nothing and click finish.
9. Save your Excel file for classroom discussion and answer the questions below.


1. Locate your data position(s) on a map of the Atlantic Ocean. Find the minimum and maximum temperature at your location(s). Compare results for different locations for dates in January, April, July and October. Discuss any major differences in temperature over the course of the year. Is the position of the Gulf Stream changing by season?

2. Can you describe how the sea surface temperature of the Gulf Stream affects the weather along the East Coast and in Europe? How do you think the position of the Gulf Stream may affect offshore operations such as the fishing industry? Do the results agree with your hypotheses?

3. At latitude 45 N, winter temperatures of Bar Harbor, Maine can get as low as -15 C while at Newquay, United Kingdom it can get as low 41 C. Can you draw any conclusions about the difference in climate between western and eastern shores of the North Altantic Basin?


Read the article linked above and discuss in class:

1. It is claimed that the Gulf Stream brings mild winter climate to Eastern Europe. Discuss if this is myth or fact, or simply an incomplete explanation.

2. What effects will global warming have on the Gulf Stream? Discuss the climate feedbacks described in the article.

Lesson plan contributed by Rex Roettger, Aguadilla, Puerto Rico

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