The Impact of Snow and Ice Morphology on Radar Altimetric Determination of Sea Ice Thickness

Thursday, 17 December 2015
Poster Hall (Moscone South)
Thomas Newman1, John M Brozena2, David Ball3, Robert Liang2, Andrei Abelev2 and Joan M Gardner4, (1)Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States, (2)Naval Research Lab, Washington, DC, United States, (3)Exelis Inc, Herndon, VA, United States, (4)US Naval Research Laboratory, Washington, DC, United States
Observations of the current state of Arctic sea ice indicate a trend towards a younger, thinner and more mobile pack that exhibits significant inter-annual variability. Radar returns from altimeters are impacted by the morphology of snow and ice features on the surface as well as the characteristics of radar pulse penetration through the snow pack. Together these contribute to uncertainty in the procedures for deriving sea ice freeboard from radar altimeter data. We make use of dense lidar grids and airborne snow radar measurements, collected on the sea ice pack north of Barrow, Alaska by the Naval Research Laboratory in 2014 and 2015, to investigate the effect of ice surface morphology on radar altimeter measurements. We quantify the effect of surface morphology using a nested approach that includes forward modeling, snow radar data and a comprehensive set of in situ measurements. Our results allow us to better constrain the altimetric uncertainty resulting from ice surface morphology, with respect to ice type. This will lead to an enhanced understanding of sources of uncertainty in altimeter-derived sea ice thickness products.