Around the Water Cooler: HICO and H20
By Dustin Renwick
Even without a call from President Kennedy, outer space has enthralled America again. With the Mars rover, the inauguration of the commercial space industry, and a human diving from space unencumbered by vehicles, space is back in the public discussion.
EPA’s link to space exploration comes from the other final frontier: our oceans.
Blake Schaeffer, an EPA research ecologist, led a group that explored the use of space-based technology to monitor coastal waters as part of the EPA’s Pathfinder Innovation Projects.
The team used the Naval Research Laboratory’s Hyperspectral Imager for the Coastal Ocean (HICO), mounted on the International Space Station.
Satellite sensors are typically designed for darker depths in the open ocean; light reflected from land prevents accurate measurements in waters close to shore. HICO was calibrated for coastal waters, but the EPA has never used remote satellite monitoring to measure water quality.
“We wanted to show something like this was possible,” Schaeffer said.
Images from HICO reveal a spectrum that EPA scientists analyze to determine water quality factors such as concentrations of chlorophyll and organic matter.
The difference of effort between current boat-based surveys and remote sensing via outer space is akin to creating fabric. A factory of people armed with knitting needles could weave cloth, but operating a loom could produce better results in less time and with fewer people.
Today’s monitoring strategies involve field observations that pinpoint tiny areas out of the thousands of beaches, inlets, and estuaries carving the U.S. coastline. Similar to the efficiency of a loom, HICO operations allow scientists to monitor larger swaths of water and conduct research previously limited by time, personnel or geographic constraints.
“We’re seeing right up into where freshwater streams and rivers meet the headwaters of estuaries, and that’s great,” said team member Darryl Keith, an EPA research oceanographer.
Keith said scientists have models to estimate water quality in freshwater and saltwater environments, but “few models cross the interface between these environments.” HICO helps integrate the two.
Team researchers are also developing a smartphone application that will make their data accessible to the general public.
The project was based in Florida, but an ideal future could bring national water quality forecasts similar to today’s weather reports. If an algal bloom closes your favorite swim spot, you’ll have the information before you leave for the beach.
About the author: Dustin Renwick works as part of the innovation team in the EPA Office of Research and Development.
Editor's Note: The opinions expressed in Greenversations are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.
“But the EPA has never used remote satellite monitoring to measure water quality.” Why not? Several of scientists have been doing it for years! Numerous water bodies are considered impaired and have TMDLs created for them, but there is an obvious lack of monitoring and adequate measurements being implemented. Instead of taking one sample from an impaired water body every month or so (and pay for the lab costs) why not receive more consistent sampling, with a much denser net of measurements being taken, all by satellite?
Hi, and thanks for your comment. I spoke with Blake Schaeffer, and this is what he told me:
“The highly reflective surface of land compared to that of water causes error flagging of remotely sensed water quality data at the coastline. Light contamination from land, bottom reflectance and the optical complexity of waters in estuaries and inland waters typically confound the derivation of remote sensing products. Methods developed with ocean color satellites such as MODIS, MERIS and SeaWiFS have demonstrated some success for deriving water quality products in estuaries and inland waters, but most of the focus has been on open ocean waters.”