Late Winter Observations of Sea Ice Pressure Ridge Sail Height

Abstract

Analysis of high-resolution imagery acquired by the Digital Mapping System during annual, late-winter NASA Operation IceBridge surveys of Arctic sea ice between 2010 and 2018 reveals that pressure ridge sail heights ( ${H} _{\mathbf {S}}$ ) vary regionally and interannually. We find distinct differences in ${H} _{\mathbf {S}}$ distributions between the central Arctic (CA) and the Beaufort/Chukchi Seas region. Our results show that differences with respect to ice type occur within the tails of the ${H} _{\mathbf {S}}$ distributions and that the 95th and 99th percentiles of ${H} _{\mathbf {S}}$ are strong indicators of the predominant ice type in which the pressure ridge formed. During the first part of the study period ${H} _{\mathbf {S}}$ increased, with the largest sails observed in the winters of 2015 and 2016, after which ${H} _{\mathbf {S}}$ declined, suggesting that the most heavily deformed sea ice may have drifted beyond the area surveyed and exited the CA. Our analysis of the interannual and regional variability in sea ice deformation in the western Arctic during the last decade provides an improved understanding of sail height that will help advance ridge parameterizations in sea ice models.