Tracking Water Using NASA Satellite Data

Jet Propulsion Laboratory, National Aeronautics and Space Administration

Using real data from NASA's GRACE satellites, students will track water mass changes in the U.S., data that measures changes in ice, surface and especially groundwater. The background information includes an animated video about where water exists and how it moves around Earth, as well as short video clips to introduce the GRACE mission and explain how satellites collect data. Students will estimate water resources using heat-map data, create a line graph for a specific location, then assess trends and discuss implications. This activity illustrates the importance of water resources and how changes in climate are closely linked to changes in water resources. The activity could fit into many parts of a science curriculum, for example a unit on water could be connected to climate change.

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Notes from our reviewers

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Teachers will need to explain the term "heat-map" as the term for all such maps colored to represent a measurement--not just heat. Then for the particular map used in the activity, the zero point (white) needs to be explained as zero change from the previous month's average. Teachers also can emphasize that the colors are actual measurements of where the mass of water is in the landscape compared to the previous month, as determined by the GRACE satellites. Teachers have the option of cutting down on the time this activity takes by choosing one of the several videos provided about the GRACE satellite mission. This activity could be used in coordination with a social studies class studying 21st century events which have been affected by drought, flooding, glacial melt, and groundwater depletion.
This resource teaches students about the GRACE and GRACE-FO missions, using measurements of gravity to track the amount of water in a region, and changes over time. It also includes videos about groundwater in the water cycle, mass, and the engineering technique pairing the satellites. Reviewers were initially unsure how to interpret the colors and units on the map in step 5. The explanation for 'equivalent water height' can be found on the MASCON FAQ, [https://ccar.colorado.edu/grace/faq.html#Q2]. Basically, the blue colors indicate water moving into an area, and red colors illustrate a loss of water. Comments from expert scientist: This resource allows students to examine scientific data and, along with the discussion points suggested in the instructions, demonstrate its application to real world situations. The units of the measurement shown in the maps- mm H2O - and what that represents is not clearly explained, nor is it clearly explained what the color bar indicates in the instructions. No resource is given for teachers to access the original GRACE data or its accompanying documentation, which could provide further information about the mission and data. Scientific strengths: The resource contains background information about the water cycle, gravity, the GRACE mission itself, and how the satellites can measure water on the surface of the earth in easy to understand and engaging videos. Suggestions: The resource refers to GRACE-FO as something that is forthcoming, although it has now been in orbit for over 2 years. It could be updated to include information about when GRACE-FO was launched, and perhaps show some of the new data collected. I do not believe this detracts from the value of the activity.
This resource asks students to estimate changes in water resources using heat-map data from NASA's GRACE missions, create a line graph for a specific location, then assess trends and discuss implications. Groups make graphs for a certain location over a one-year time period and these graphs are put together to get a sense of the change in water at that location over longer periods of time. There is a lot of background information included, (including complete teacher preparation materials), and the videos allow time for discussion from students. The lesson is engaging and well organized, includes all data necessary, as well as standards, a suggested assessment rubric, and links to extension activities. Some background on graphing skills and vocabulary are needed. The degree of complexity and graphing can be tailored to suit the needs of the class, but the development of graphing skills is always useful to help students understand scientific information. The activity questions are strong, but the assessment section would benefit from questions focused on the implications of the data. Videos are all credited to reliable sources and are freely available on YouTube.
The graphing activity has detailed instructions, which is helpful since it is complicated to ensure the different groups' graphs will be plotted so that all of the graphs can be put together. Graphing can be done with pencil and paper, Excel, Google Sheets, or other spreadsheet software. All data is easily accessible with internet connection, or can be downloaded ahead of time. The lesson is complete, well organized, and easy to implement.