Satellite data are an important source of environmental information and monitoring. Satellite imagery is available from the National Atmospheric and Space Agency (NASA): http://seawifs.gsfc.nasa.gov/SEAWIFS.html

What are some of the current topics shown in images on this page? Have you heard or read about these topics in the news?

Go to the big maps if you have a fast Internet connection: http://seawifs.gsfc.nasa.gov/cgi/level3.pl
Click on the NDVI (normalized difference vegetation index) option in the table of themes. NDVI is a measure of how green the vegetation is. Then click on the current month in the table of months and years. (Click on a map to see a larger version.) Compare the view of the current month with the views at several different times of year. Find your location on the map. Can you identify local features that should (or should not) be green in the various months? How does the amount of vegetation in your area affect local environmental conditions? If satellites had existed 100 years ago, how might the view they would have shown differed from what we see today?