July 26, 2011
The scene in the video (above) might look like the surface of the moon, but the feature is actually the mottled underside of a melt pond on sea ice in the Arctic Ocean. Here’s a look back at one of ICESCAPE’s numerous tools that scientists used to probe the depths of this rarely observed environment.
Ice blocks some incoming light, but not all of it, and scientists want to know how much makes it through and is available for photosynthesis. To find out, Karen Frey, of Clark University, managed the ICEPRO and ICEPOD duo at the mission’s nine ice stations. The instrument package provides profiles of optical properties below sea ice and melt ponds, a region hidden from view of satellites.
Frey lowered the ICEPRO below to pond to profile optical properties down to about 50 meters. Credit: NASA/Kathryn Hansen
The device has sensors that look up and down through the water column. The upward-looking sensor measures downwelling light, and the downward-looking sensor measures upwelling light. David Mayer, of Clark University, recorded the data with the click of a button on a laptop.
Meanwhile, a tripod or “ICEPOD” measures incoming light at the surface, so scientists can calculate the percent of total light transmitted through the ice.
From the surface to about 10 meters deep, water below a melt pond will “see” much more light than water below bare ice. By about 20 meters down, however, contributions have all mixed together and water below a pond will about the same amount of light as water below bare ice.