Lab 5: Air, Water, Land, & Life: A Global Perspective

Part A: Viewing Earth from Space

Before satellites, remote sensing images were obtained in a variety of creative ways. Early remote sensing images in the mid to late 1800s were taken by hot-air balloonists. In 1897, Alfred Nobel (for whom the Nobel prize is named) took the first aerial photograph from aboard a rocket. In the early twentieth century, remote sensing images were even taken by cameras strapped to fleets of pigeons and kites. As technologies advanced throughout the 1900s, remote sensing via cameras aboard airplanes became valuable for things like wartime reconnaissance, urban development, disaster damage assessment, land use surveys, agricultural status, and oil exploration. But it wasn't until the latter half of the twentieth century, with the development of artificial satellites, that remote sensing expanded to the global scale. Today, more than a dozen NASA satellites keep constant watch over Earth.

To learn more about remote sensing, read the NASA article Remote Sensing.

NASA's Blue Marble

The full-Earth images below are the western- and eastern-hemisphere views of NASA's spectacular "blue marble" image of Earth. Scientists and visualizers created these true-color images by stitching together months of observations of the land surface, oceans, sea ice, and clouds into a seamless, true-color mosaic of every square kilometer (0.386 square mile) of our planet. Click here to learn more about these images.

1. Carefully examine the "blue marble" images below.
2. Identify elements of the four major components of the Earth system (atmosphere, hydrosphere, pedosphere, biosphere).
   
   
   

   Images courtesy of NASA. Click image to enlarge.
   
   

NASA NEO

Earth system processes take place in and between the atmosphere, water, soil, and living components of the planet. These processes also include energy from the Sun, and the gases and particles that enter the atmosphere and oceans from both natural and anthropogenic (human-related), sources. The NASA Earth Observations (NEO) site is a great place to find imagery of NASA Earth science datasets. NEO has over 20 distinct energy, atmosphere, ocean, land, and life datasets, which are available as global snapshots in daily, weekly, and monthly time spans. In this part of the investigation, you will examine images of the Earth, looking for available information (data displayed, unit of measure, range of values, etc.) then for any noticeable patterns within the image. 

1. Work in small groups to explore satellite images and data maps of the four components of the Earth system. Each group will explore at least one image from each category. Here are some suggested datasets for each group.
   
   Group 1—Energy
   Dataset Options:
   • Solar Insolation
   • Net Radiation
   • Aerosol Optical Thickness
   • Cloud Fraction
   • Rainfall
   • Sea Surface Temperature (MODIS 2002+)
   • Sea Ice and Snow Extent, Northern Hemisphere
   • Land Surface Temperature [Day]
   • Land Surface Temperature [Night]
   • Land Cover Classification
   • Vegetation Index
   • Population
2. Go to the NASA Earth Observations (NEO) website. The NEO Web site will open in a new browser window.
3. NEO organizes datasets into five categories: Ocean, Atmosphere, Energy, Land, and Life. Click on one of the buttons to see the list of available datasets for each category.
   Show me an example
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   Example: If you are in the "Energy" group, you might choose to look at a global map of population. Start by clicking on the "Energy" button above the changing images to display the "Energy Datasets."
   

   

   
   
   
4. Select the dataset you want to display on the map. The display window loads the most recent map.
   Show me an example
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   Continuing with our Energy example, select the "Solar Insolation" dataset.
   

   

   
   
   The display window loads the most recent map of Solar Insolation.

   

   
   
   
5. Carefully examine your map.
6. Find out about the dataset used to produce the map.
   
   • Scroll down to About this dataset to learn more details about what your map is showing.
     Show me how
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     Click 'Intermediate' for additional information.
7. Explore your dataset in more detail using NEO's Image Composite Explorer (ICE) Tool. Click Add to Analysis to add it to the Analyze box (grayed out) above.
   
   
   
   
8. Click Analyze. A new Analysis Options window will open. 
   
   
   
   
   
   
   
   
9. Click on the field below File size in the Select Area box below the image and set the resolution to 0.5 degrees. This will help the image load faster for analysis. Then click Launch Analysis.
   
   
   
   
10. Once your scene loads, click the checkbox for Data Probe and begin exploring your image. Move your mouse over the image to display latitude, longitude, and values for data points on the map.
    
    
    
    
11. Click the checkbox for Zoom/Roam to zoom in on areas of interest. Click the Reset View button to reset the image. To simultaneously explore the data in your image both visually and graphically, try selecting the Plot Transect feature (a transect is a path along which observations are made). Click and drag your mouse across the image to define a transect. Experiment with different areas of the world. Try plotting North-South and East-West transects to look for patterns in the data. Notice that as you move the cursor, a graph is generated. Click the X in the upper right of the graph to close.
    
    Show me an example
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12. With your group, continue to explore your image and come up with answers to the following Stop and Think questions:
    
    

    Stop and Think

    1: What variable did you examine and what is the range of values shown on the scale bars?
    
    2: Where in the world do you find the highest and lowest values (the extremes) of the data in your images?
    
    3: Why do these locations experience the extremes and not other locations?
    
    4: Are there any noticeable patterns in the data? Are patterns different on different continents? Are patterns different over water than over land? Explain these patterns.
13. Designate a spokesperson to report your group's observations.
14. Share what you found with the rest of the class. Include answers to the Stop and Think questions in your group's presentation.
15. As a class, discuss interconnections between the datasets examined by each group. For example, do the maps hint at any relationships between insolation and water or land surface temperatures? Between total rainfall and vegetation index?