24 Mar 2017

NASA pulled off a scientific double play in Hawaii this winter, using the same instruments and aircraft to study both volcanoes and coral reefs. Besides helping scientists understand these two unique environments better, the data will be used to evaluate the possibility of preparing a potential future NASA satellite that would monitor ecosystem changes and natural hazards.
The advantages of studying active volcanoes from the airrather than the ground are obvious. Coral reefs may not offer the same risks in a close encounter that volcanoes do, but there's another good reason to study them by remote sensing: they're dotted across thousands of square miles of the globe. It's simply not feasible to survey such a large area from a boat. So NASA has been monitoring coral reefs by satellite and aircraft for several decades. Recent airborne efforts have used sensors that provide better spatial and spectral resolution than currently available from NASA satellite systems.

"Reefs are threatened by bleaching due to rising sea surface temperatures as well as, to some degree, by increasing acidification of ocean waters," said Woody Turner of NASA Headquarters in Washington, the program scientist for the recent Hawaii study. "On top of that, since they're coastal ecosystems, they are also subject to sediment and other effluents running offshore. We have an urgent need to get a handle now on how reefs are changing."
Over the past four years, NASA has flown a series of research flights over California, carrying airborne prototypes of instruments in preparation for a possible future satellite mission called the Hyperspectral Infrared Imager (HyspIRI), now in the conceptual design phase. The Golden State has many diverse landscapes to test the instruments' observational capabilities, but not coral reefs or erupting volcanoes. This winter's HyspIRI Hawaii field campaign filled that gap.

To get the next best thing to a satellite's point of view, HyspIRI Hawaii used a high-altitude ER-2 aircraft from NASA's Armstrong Flight Research Center, Palmdale, California. During the study, the aircraft was based at Marine Corps Base Hawaii, on the island of Oahu. Flying at approximately 60,000 feet (18,000 meters) and thus above most of Earth's atmosphere, the ER-2 carried the Airborne Visible and Infrared Imaging Spectrometer(AVIRIS), developed by NASA's Jet Propulsion Laboratory, Pasadena, California, and the MODIS-ASTER Airborne Simulator (MASTER), developed by NASA's Ames Research Center, Moffett Field, California. AVIRIS is an imaging spectrometer that observes the complete reflected spectrum of light in the visible and shortwave infrared wavelengths. MASTER has multiple observational channels in the thermal infrared wavelengths. Together AVIRIS and MASTER provide the same combination of spectral bands planned for the future HyspIRI mission -- and powerful data for current coral reef research.

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NASA coral reef studies in Hawaii this winter will help scientists understand this unique environment.