EarthLabs > Earth System Science > Lab 7: A Year in the Life of the Earth System > 7A: The Earth System in 2009

Lab 7: A Year in the Life of the Earth System

Part A: The Earth System in 2009

In this part of the investigation, you will work in small groups to examine 12 monthly images of the variable/dataset you explored in Lab 6, looking for any changes that occur over the course of the most recent year. NOTE: If you are unable to download the most current data from NEO, scroll to the bottom of the page for alternate instructions, using example files for the year 2009.

  1. Create a new folder on your computer to hold the images you will download. Name your folder to match the dataset you will download (Insolation, Aerosols, SST, Land Temp, or NDVI).

  2. Go to the NASA Earth Observations (NEO) web site. The NEO Web site will open in a new browser window. If the page does not display properly, check your browser Preferences to make sure both Flash and Java are enabled.

  3. Select and display a monthly map for January of the last full year (e.g., if it is November 2010, you should select and display a map for January 2009) for your group's assigned dataset:
    • Energy Group: Solar Insolation
    • Air Group: Aerosol Optical Thickness
    • Water Group: Sea Surface Temperature (SST)
    • Land Group: Land Temperature
    • Life Group: Vegetation Index (NDVI)
    Example: Energy Group
    1. Click on the Energy tab under the map to display all of the Energy Datasets.


    2. Locate the Solar Insolation dataset in the list and click on it.


    3. The display window loads the most recent monthly map of Solar Insolation. To select a particular month, refer to the Search Results field below the map. This field lists the most recent 10 months of maps. Use the Next link at the bottom of the list to navigate to older datasets if necessary.


    4. Click on the "+" symbol to expand the field for a given date range.


    5. Click View to display the map for that date range.



  4. Create a new folder on your computer to hold the 12 images you will download. Give the folder a name that describes the images you will download (e.g., Solar Insolation 2009 or Sea Surface Temperature 2010).

  5. You should still have the January image for your group displayed in NEO. Download this image at a resolution of 0.5 degrees.

    1. In the Download Options box, change the selection from Full to Resize. Do not change the file format (keep it as JPEG). Select a fixed resolution of 0.5 degrees. Click the Get Image button to generate the image. The resized image will open in a pop-up window.


    2. Right-click (control-click on a Mac) on the image to download it. Save the file into the folder you created and name it 01_name.jpg, replacing "name" with insolation, aerosol_thickness, sst, land_temp, or ndvi depending on your group. For example, if you are in the Energy Group, you should call your January image 01_insolation.jpg. If you are in the Atmosphere Group, name your image 01_aerosol_thickness.jpg.

    3. Close the pop-up window.

  6. Click on the "+" symbol to expand the field for February. Click View to display the February image. Use the same procedure as above to resize and generate an image with a fixed resolution of 0.5 degrees. Save the image as 02_name.jpg.

  7. Repeat this process for March through December so that you end up with a total of 12 images. Use the Prev link at the bottom of the Search Results box to access more recent data as necessary. You should end up with a total of 12 images, named from 01_name.jpg to 12_name.jpg.

  8. If your computer does not already have ImageJ, a free image processing software program developed at the National Institutes of Health, download and install it now.
    • Go to the ImageJ Download page , and download and install the application for your operating system
      Click the ImageJ Download page and it will open in a new window. Click the link that appears directly below the name of your computer's operating system (e.g. Mac, Linux, Windows). This action will transfer a compressed file of the software to your computer. Your browser should automatically expand the file, creating an ImageJ folder on your computer's hard drive.
      ImageJ Download page
    • For more details, or if you have problems running the application, access ImageJ's Installation Instructions then select your operating system.
    • NOTE: Instructions for this activity were written using ImageJ version 1.44c. Commands may vary slightly for different versions of the software.

  9. Launch ImageJ by double clicking on the application icon ImageJ icon or by selecting it from the Start menu.

  10. Choose File > Import > Image Sequence... and navigate to the folder where you stored your 12 monthly images.



  11. Select the first image in the sequence (01_name.jpg) and then click the Open button. Specify the Sequence Options. Use all 12 images, beginning with image 1 and incrementing by one. Do not scale the images. Check Sort Names Numerically and click OK.

    1. Select the first image in the sequence and then click the Open button.
      ImageJ Import Image Sequence 2

    2. Specify the Sequence Options.
      • Number of Images: 12
      • Starting Image: 1
      • Increment: 1
      • Scale Images: 100%
      • Check Sort Names Numerically
      • Click OK
      ImageJ Sequence Options




  12. All 12 images will be imported into a stack with the same name as the folder you stored them in. The individual images in a stack are called "slices" in ImageJ. The image below shows the first of the twelve total slices (1/12). The width and height of the stack in pixels, and the size of the stack, in this case 12 MB, are displayed at the top of the window just below the name of the stack.



  13. Choose File > Save As > Tiff... to save the stack as Folder_Name.tif. (Folder_name will be replaced with the actual name of your folder.)

  14. Choose Image > Stacks > Tools > Animation Options... to set the speed of the animation to one frame per second and animate your image stack.
    1. Choose Image > Stacks > Tools > Animation Options...

    2. Set the Speed of the animation to 1 frame per second. Animate all the frames by setting the First Frame to 1 and the Last Frame to 12. Check Start Animation and click OK. The stack will start moving through the slices.



  15. Use Image > Stacks > Tools > Start Animation and Image > Stacks > Tools > Stop Animation to start and stop the animation. You can also use the play/pause button at the bottom left of the stack window or use the slider bar at the bottom of the image to step through slices one at a time.


  16. Watch the animation several times through, looking for changes over time. Click on your group name below to view the scale bar for your image sequence.
    Insolation: What do the colors mean? The colors in these maps show how much sunlight (in Watts per square meter) fell on the Earth's surface during the given time period.
    Insolation scale

    Aerosols: What do the colors mean? In the maps shown here, dark brown pixels show high aerosol concentrations, while tan pixels show lower concentrations, and light yellow areas show little or no aerosols. Black shows where the sensor could not make its measurement.
    Aerosol thickness scale

    SST: What do the colors mean? These maps show satellite measurements of the sea's surface temperature (in degrees Celsius) for a given day, or for a span of days. The coldest temperatures (down to -2°C) are purple and the warmest temperatures (up to 45°C) are shown in white. The black areas show where the satellite could not measure sea surface temperature.
    SST scale

    Land Temperature: What do the colors mean? The colors on these maps represent temperature patterns of the top millimeter (or "skin") of the land surface — including bare land, snow or ice cover, urban areas, and cropland or forest canopy — as observed by MODIS in clear-sky conditions for the time period indicated. Yellow shows the warmest temperatures (up to 45°C) and light blue shows the coldest temperatures (down to -25°C). Black means "no data."
    Land Temperature scale

    NDVI: What do the colors mean? Dark green areas show where there was a lot green leaf growth; light greens show where there was some green leaf growth; and tan areas show little or no growth. Black means "no data."
    NDVI scale


  17. With your group, identify annual cycles for your variable by answering the following Stop and Think questions. Hint: if you are having trouble locating significant changes, try focusing your attention on one location on the image throughout the year.

    Stop and Think

    1: What changes do you see through the year? What explanations can you suggest for these patterns?

    2: Choose a location or region. During which months do the extreme highs and lows occur? What explanations can you suggest for the timing of those extremes?

    3: Which regions experience both the extreme highs and lows? Which regions don't experience the extremes? Why do you think this happens?

    4: What differences, if any, do you find between the year's variations over the oceans versus the year's variations over the continents?

    5: Are there regions that remain relatively unchanged over the year? Why do you think this happens?


  18. Designate a spokesperson to report your group's observations.

  19. Share your discoveries of patterns and your interpretation of those patterns with the rest of the class.

  1. Right-click (control-click on a Mac) to download a stack of 2009 monthly images for your group.

  2. If your computer does not already have ImageJ, a free image processing software program developed at the National Institutes of Health, download and install it now.
    • Go to the ImageJ Download page , and download and install the application for your operating system
      Click the ImageJ Download page and it will open in a new window. Click the link that appears directly below the name of your computer's operating system (e.g. Mac, Linux, Windows). This action will transfer a compressed file of the software to your computer. Your browser should automatically expand the file, creating an ImageJ folder on your computer's hard drive.
      ImageJ Download page
    • For more details, or if you have problems running the application, access ImageJ's Installation Instructions then select your operating system.

  3. Launch ImageJ by double clicking on the application icon ImageJ icon or by selecting it from the Start menu.

  4. Choose File > Open. Browse to the location where you saved the image file for your group and open it. You'll notice that the file does not just contain a single image, but rather a stack of twelve monthly images (January-December, 2009). The individual images in a stack are called "slices" in ImageJ. Use the scroll bar or arrows at the bottom of the window to move through the slices in the image sequence. The individual images are labeled by month in the top left of the image window (1 = January, 2 = February, etc.).
    Insolation Image Sequence Example




  5. Choose Image > Stacks > Tools > Animation Options... to set the speed of the animation to one frame per second and animate your image stack.
    1. Choose Image > Stacks > Tools > Animation Options...

    2. Set the Speed of the animation to 1 frame per second. Animate all the frames by setting the First Frame to 1 and the Last Frame to 12. Check Start Animation and click OK. The stack will start moving through the slices.



  6. Use Image > Stacks > Tools > Start Animation and Image > Stacks > Tools > Stop Animation to begin and end the animation.

  7. Watch the animation several times through, looking for changes over time. Click on your group name below to view the scale bar for your image sequence.
    Insolation: What do the colors mean? The colors in these maps show how much sunlight (in Watts per square meter) fell on the Earth's surface during the given time period.
    Insolation scale

    Aerosols: What do the colors mean? In the maps shown here, dark brown pixels show high aerosol concentrations, while tan pixels show lower concentrations, and light yellow areas show little or no aerosols. Black shows where the sensor could not make its measurement.
    Aerosol thickness scale

    SST: What do the colors mean? These maps show satellite measurements of the sea's surface temperature (in degrees Celsius) for a given day, or for a span of days. The coldest temperatures (down to -2°C) are purple and the warmest temperatures (up to 45°C) are shown in white. The black areas show where the satellite could not measure sea surface temperature.
    SST scale

    Land Temperature: What do the colors mean? The colors on these maps represent temperature patterns of the top millimeter (or "skin") of the land surface — including bare land, snow or ice cover, urban areas, and cropland or forest canopy — as observed by MODIS in clear-sky conditions for the time period indicated. Yellow shows the warmest temperatures (up to 45°C) and light blue shows the coldest temperatures (down to -25°C). Black means "no data."
    Land Temperature scale

    NDVI: What do the colors mean? Dark green areas show where there was a lot green leaf growth; light greens show where there was some green leaf growth; and tan areas show little or no growth. Black means "no data."
    NDVI scale


  8. With your group, identify annual cycles for your variable by answering the following Stop and Think questions. Hint: if you are having trouble locating significant changes, try focusing your attention on one location on the image throughout the year.

    Stop and Think

    1: What changes do you see through the year? What explanations can you suggest for these patterns?

    2: Choose a location or region. During which months do the extreme highs and lows occur? What explanations can you suggest for the timing of those extremes?

    3: Which regions experience both the extreme highs and lows? Which regions don't experience the extremes? Why do you think this happens?

    4: What differences, if any, do you find between the year's variations over the oceans versus the year's variations over the continents?

    5: Are there regions that remain relatively unchanged over the year? Why do you think this happens?


  9. Designate a spokesperson to report your group's observations.

  10. Share your discoveries of patterns and your interpretation of those patterns with the rest of the class.


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