Monitoring Global Ecosystems From Space

Satellite data will improve scientists’ understanding of global dynamics and processes, and aid the development of interactive Earth models for predicting global change. NASA’s Terra and Aqua satellites use an onboard Moderate Resolution Imaging Spectroradiometer (MODIS) to create images of the Earth’s entire surface every couple of days. Terra passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon.

With six onboard instruments including MODIS, Aqua collects extensive information about the Earth’s water cycle – documenting global temperature variations, precipitation and evaporation, changes in ocean circulation, and cloud and surface water processes that affect climate. The satellite recently captured the formation and evolution of the storm system that spawned the devastating F-4 tornado in Moore, Oklahoma, US. MODIS provided detailed images that led to the first (and subsequent) tornado warnings, and continued to show the storm’s movement every 15 minutes.

Aqua also measures variables such as aerosol use, vegetation cover, organic matter in oceans, and air, land, and water temperatures. The blue-green swirls in Aqua’s true-color satellite images indicate an abundance of phytoplankton in bodies of water such as the Bay of Biscay, off the coast of France. Although these microorganisms live year-round, explosive blooms occur only when conditions are right. Scientists have found links between climate change and spring bloom patterns, which suggest phytoplankton are sensitive to fluctuations in environmental conditions such as wind intensity, temperature, and light availability. This is of particular concern due to phytoplankton’s life-sustaining role in the ocean, and its production of more than half the Earth’s oxygen supply.

Aqua broadcasts all instrument data on X-Band (Terra also broadcasts select MODIS data), and the NASA Direct Readout Laboratory makes available tools and algorithms to facilitate processing for real-time applications. In turn, NASA’s Earth Observing System Data and Information System (made up of processing facilities and Earth Science Data Centers across the US) captures, processes, and distributes data to researchers around the world. Ultimately, NASA’s Earth observing satellites supply hundreds of millions of data files each year, enabling research in a range of Earth science disciplines. -- Source: Sara Engel, i SGTW