Analysis of sea ice motion and deformation using AMSR-E data from 2005 to 2007

Abstract

Dynamics of Arctic sea ice, including motion and deformation, are studied utilizing data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (EOS) (AMSR-E) during 2005 and 2007. We first derive sea ice motion maps from the satellite data in a grid of 100 km × 100 km using a two-dimensional wavelet method. These sea ice motion results are compared with those derived from buoy data from the International Arctic Buoy Programme. Secondly, it is well known that sea ice deformation can be characterized by a strain-rate tensor calculated from the ice velocity field. Two components of the strain-rate tensor quantify the divergence and the shearing of the ice field, respectively. Daily maps for both sea ice motion and strain-rate tensor, as well as monthly averages and spatial sums, are computed and analysed. Comparison of the monthly ice motion maps for May 2005 and May 2007 indicates that the anti-cyclonic Beaufort Gyre and Transpolar Drift Stream in the western Arctic are relatively stronger during 2007 than 2005. Different patterns in the spring months' sea ice deformation rates as characterized by the absolute values of the strain-rate tensor are observed when we compare the data of 2007 with those of 2005 and 2006. The sea ice deformation activities in the spring of 2007 happen earlier and are relatively stronger than that of 2005 and 2006. These results might help to explain why the sea ice extent in the summer of 2007 is unprecedentedly low.