Animation of NDVI over the course of a year across the globe
| This animation shows the level of "greenness" across the globe for the period beginning February 1995 and ending January 1996. The "greenness" of a certain part of the Earth is directly related to how much vegetation exists there at a certain time. During the months of June, July and August, the northern hemisphere appears very green, while the southern hemisphere appears less green. However, in the months of December, January and February, the opposite is true. For the most part, the amount of sunlight striking a part of the Earth during a month is largely responsible for the level of vegetative activity. If a region receives enough rainfall, then the more sunlight a region receives (that is, during a hemisphere's summer months), the greater the possibility that that region will experience an increase in new plant growth. During a hemisphere's winter period, however, less sunlight reaches the surface, and that hemisphere will experience a decline in vegetation growth. In fact, plants (in order to survive) generally senesce (or hibernate) during the winter in response to colder conditions and less sunlight. |
Credit: Dylan Prentiss, Department of Geography, UCSB
For more info: http://www.geog.ucsb.edu/~dylan/mtpe/biosphere/topics/veg/ndvi.html