The Role of Satellite Imagery in Climate Change Research

Dr. Kevin Arrigo is a Professor in the Department of Environmental Earth System Science at Stanford University. He is the Chief Scientist for NASA’s ICESCAPE (Impact of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment) mission this summer onboard US Coast Guard Cutter HEALY.

If ICESCAPE were a movie, I would begin its story by starting with a remote but panoramic camera shot of the Arctic Ocean, and only then, zoom in. Although I’m not a cinematographer, ICESCAPE makes use of technology that provides a similarly broad context for our field program – satellite imagery.

Satellite remote sensing plays two important roles within ICESCAPE. First, by analyzing daily satellite images of everything from sea ice cover to ocean temperature to the concentration of chlorophyll in the water, we can conduct a more efficient sampling program. Want to sample heavy pack ice? Or avoid it? Satellites tell us where to go. Want to collect seawater samples with lots of phytoplankton? Satellites tell us where they are.

The second role played by satellite imagery is a bit different –- it is used to “fill in the blanks” in our field program. Even though ICESCAPE will sample a big chunk of the Chukchi and Beaufort seas, we can’t be everywhere all the time. That would take lots of ships, lots of time, and lots of money. But satellites can tell us what conditions were like before we arrive, after we leave, and in areas we don’t sample. The result? A better understanding of what we are seeing while we are here.

But this is a two-way street. We can help satellite data, too. Robert Frouin (Scripps Institution of Oceanography) is working on ways to extract more information from satellite images when sea ice or high clouds are around. Formerly, satellite pixels (like those tiny dots that make up a picture in your newspaper) that were “contaminated” by clouds or sea ice were discarded or ignored. Not anymore. Frouin’s approach works kind of like those TV shows where the star pushes a button and magically makes a fuzzy picture look sharper. And in a region as cloudy and ice covered as the Arctic, every scrap of information helps!

Finally, field data collected during ICESCAPE by Greg Mitchell (Scripps Institution of Oceanography), Stan Hooker (NASA Goddard Space Flight Center) and Kevin Arrigo (Stanford University) will be used to ensure that satellite data, and the products that are derived from them, are as accurate as they can be (but more about this in later posts).

So the two way street continues. Satellite data improves the science of ICESCAPE while the science of ICESCAPE improves satellite data.