Sea Ice from Space

NASA's Earth Observatory recently featured Arctic sea ice on its image of the day page.

NASA Earth Observatory image by Jesse Allen, using data from the National Snow and Ice Data Center.

The picture on the right shows sea ice concentrations in Sept. 2010, and the one on the left shows Mar. 2011 concentrations. The yellow line demarcates median sea ice extent in those months from 1979-2000. You can really tell how the ice extent has shrunk since that period. Watch the slide show at this link to see how Arctic sea ice concentrations have changed year by year over the past decade.

Researchers studying algae (phytoplankton) in the open ocean often use satellites like the recently retired SeaWiFS to track chlorophyll concentrations (and, by proxy, phytoplankton growth) over time. For those of us studying sea ice algae, though, we can only use satellite images to learn about how that ice changes; our organisms of study live at the base of the thick layer of ice covering the seas, making them rather difficult to see from space.