Landfast sea ice extent in the Chukchi and Beaufort Seas: The annual cycle and decadal variability

摘要: Abstract Through analysis of over 2500 synthetic aperture radar (SAR) scenes spanning the period 1996–2008, we have compiled most comprehensive dataset to date on landfast sea ice extent and its annual cycle in Chukchi Beaufort Seas. Our results show that central western Sea forms earlier, breaks up later, occupies deeper water extends further from shore than Sea. The differences timing are largely due regional contrasts southward advance pack early winter onset spring thaw. On other hand, suggest between two seas related number distribution recurring grounded features. These features appear as “nodes” where seaward edge (SLIE) persistently recurs multiple years. In there several such nodes occur depths around 20 m, giving rise similarity average SLIE location 20 m isobath. We attribute narrower lack a consistent relationship with bathymetry sparsity comparing our data 1973–76, find has not changed significantly last four decades. However, width decreased by coast-wide 13 km this period. again difference Over 12 cycles study period, identify trends indicating is forming later disappearing earlier approximately one week per decade. Although these statistically significant, they agreement an overall shortening season much months past three decades, revealed comparison findings for 1973–77.