Home >> Science & Nature >> Nature

How Are Satellites Used to Monitor the Ecosystem?

Satellites are advantageous in monitoring Earth's ecosystem in a number of ways. They offer global coverage of a particular aspect of the ecosystem, so that changes on a planet-wide scale can be observed; they collect data continuously instead of only at one time; and they collect high resolution data. This allows scientists to accumulate large amounts of accurate data, and helps them to see how changes in one area of the planet affect other areas, or other aspects of the ecosystem.

Vegetation Monitoring
- Vegetation --- a general term referring to land-based plant life --- is the primary aspect of the terrestrial ecosystem. Historically, data on vegetation were collected manually, making the information limited to shorter time periods and smaller places. Satellites help measure larger areas, and have been used for this purpose since the 1970s, taking measurements such as the Normalized Vegetation Difference Index, or NDVI, which is a measure of the "greenness" of the land.
Marine Ecosystems
- Marine ecosystems are an important aspect of the satellite monitoring, particularly with the looming threat of over-fishing. Satellites cannot measure fish stocks, however they are used to measure sea-surface temperature, or SST0; sea-surface height, or SSH; chlorophyll levels; oceanic winds; and levels of sea ice. These are important data in themselves, but they can also be used to learn about the habitats and migration patterns of species.
Forest Ecosystems
- Forests hold the largest portion of Earth's terrestrial carbon, so disturbances within those ecosystems, such as forest fires, are monitored by satellite. For example, the "Boreal Belt" along the circumpolar region of the globe contains the "Taiga," a large forested habitat that holds 40 percent of all terrestrial carbon. The Taiga represents the second-largest land-based biomass, behind the tropical rainforests. Three satellites play a crucial role in early detection of forest fires along this important region: the Landsat, SPOT and AVHRR satellite systems.
Global Temperature
- Temperature measurements made from space contribute to scientists' study of global warming. Satellites do not measure temperature directly, but infer temperature by measuring other variables, such as infrared and other radiation, along a pocket of air several kilometers above Earth's surface. Satellite coverage is roughly equivalent to placing static monitoring stations all around the world at 2 km intervals. This accurate and broad-gauge monitoring even allows storm systems to be detected.

Nature