DR. WALT MEIER RESEARCH SCIENTIST
National Snow and Ice Data Center Univ. of Colorado

Dr. Meier studies the Arctic sea ice using satellite data. One new instrument that he is interested in is the NASA Ice, Cloud, and land Elevation Satellite (ICESat). The Geoscience Laser Altimeter System (GLAS) sensor on ICESat measures the elevation of earth surface features with lasers.  For sea ice, ICESat measures the elevation of the top surface of the ice or snow above the sea level, called “freeboard”.  From this freeboard estimate, the total thickness of the sea ice can be derived.  However, there are many uncertainties in the measurements, including sensors and satellite orbit errors.  The largest uncertainty is in converting the elevation estimate into a total sea ice thickness because the amount of snow cover is not well known.

In order to make better use of ICESat sea ice measurements, Dr. Meier is interested in verifying measurements taken by the altimeter, using in situ measurements taken directly on the ice. He has been working with two groups to take measurements during their expeditions, IceWarrior (www.ice-warrior.com) and OneWorld (www.oneworldexpedition.com). They have measured ice thickness (using an ice drill) or freeboard (at locations where the ice bordered open water), as well as snow thickness and density measurements.  He and others at NSIDC will use these measurements to calibrate estimates taken by the NASA ICESat altimeter mission.

What will the expedition attempt to do?

The team will be able to potentially provide a third year of data to both qualify and verify the data collected by both expeditions mentioned above.