Measuring global vegetation from space in February
| One of the greatest advantages of using satellites to monitor Earth is that they can cover the entire surface in a short period of time. This allows one to compare how the planet looks at different times of the year. The image above shows the amount of vegetation present in February, at the end of the northern hemisphere winter. Notice that there is a great deal of vegetation in the southern hemisphere (where the growing season has just ended), but little in the northern hemisphere (where the growing season has yet to begin). Compare this to the image taken in September. The amount of vegetation present is based on an index of how green the surface is, which can be measured using satellite images. |
Credit: NASA/GSFC
For more info: http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/GLBDST_Education.html