On these maps, vegetation is pictured as a scale, or index, of greenness. Greenness is based on several factors: the number and type of plants, how leafy they are, and how healthy they are. In places where foliage is dense and plants are growing quickly, the index is high, represented in dark green. Regions where few plants grow have a low vegetation index, shown in tan. The index is based on measurements taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Areas where the satellite did not collect data are gray.
Land surface temperature is how hot the “surface” of the Earth would feel to the touch in a particular location. From a satellite’s point of view, the “surface” is whatever it sees when it looks through the atmosphere to the ground. It could be snow and ice, the grass on a lawn, or the roof of a building. These maps compare daytime land surface temperatures in a particular month to the average temperatures for that month from 2000-2008. Places that were warmer than average are red, places that were near normal are white, and places that were cooler than average are blue. The observations were collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
View, download, or analyze more of these data from NASA Earth Observations (NEO):
Land Surface Temperature Anomaly