EarthLabs > Hurricanes > Lab 8: Hot Water and Hurricanes > 8B: The Loop Current

Part B: The Loop Current

The Loop Current in the Gulf of Mexico. The orange color shows the warmer water of the current and arrows show the direction.
One current of special importance for hurricanes is in the Gulf of Mexico. Like the Gulf Stream, the Loop Current is a warm water current that contains considerable heat energy. In this section, you'll download an animation of the Loop Current. You'll open the file in an image processing application, ImageJ, and apply various color tables to display the data to represent temperature. This will help you visualize how the current delivers heat to the Gulf of Mexico.
  1. Right-click (ctrl-click with a one-button mouse) this link to download a .zip archive that contains an animation of the Loop Current ( 4.8MB Jan14 08). The movie contains 18 image frames, so the download may take a few minutes.
    Right-click or ctrl-click on the text link above. In the menu that appears, choose the "Save link as..." or "Save target as..." option. When prompted, choose a location to save the file and click Save.
  2. Your browser may expand the file as soon as the download is complete, or you may need to double-click the zipped file in order to expand it. Save the expanded file in an obvious place such as your desktop or in your downloads folder.
  3. Launch ImageJ by double-clicking its microscope icon.
  4. Choose File > Open... and navigate to the location where you saved the expanded Loop_Current_Movie.tif file.
  5. Play the movie by selecting Image > Stacks > Start Animation. You can control the animation manually by dragging the frame indicator along the bottom or using the arrow buttons to move one frame at a time. You can control the animation speed by choosing Image > Stacks > Animation Options. Stop the animation by choosing Image > Stacks > Stop Animation.
  6. The black-to-white color scale indicates the temperature of the surface water. Land and clouds appear black. To help you visualize the bright areas as warmer water, you can apply a range of colors to these image data.

    Select Image > Lookup Tables > then choose any of the color options available. Try several different color schemes to find one that conveys the temperatures that the data represent. Play the animation again with your favorite Lookup Table: focus on interpreting the current as a supply of heat energy to the Gulf of Mexico.

Checking In

Watch your movie to answer these questions
  • Show someone the movie with the Lookup Table you chose. Tell why you think the color scheme you chose works well for the temperature data it represents.
  • Examine the movie frames to tell how much time the animation covers.
  • Use the graphic distance scale in the upper left to make a rough estimate of the dimensions of the warm surface of the Loop Current.