A movie showing the vegetation of North America over the course of a year
| The above movie shows an index of vegetation across North America. This index (called the Normalized Difference Vegetation Index, or NDVI) is a measure of how green the surface is and is determined by instruments on a satellite. How green the surface is directly relates to how much vegetation exists there. This movie shows how the vegetation changes with the seasons over an entire year. Notice how much greener the continent is during the summer (the middle of the movie) than it is during the winter (the beginning of the movie). |
Credit: NASA/GSFC
For more info: http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/GLBDST_Education.html