Abstract
Pressure ridges are deformation features within the sea ice pack created
through the collision of sea ice floes. Pressure ridges play an
important role in ice drift and influence the mass and energy budgets of
the Arctic Ocean. Over the past decade annual airborne surveys over
Arctic sea ice have been conducted in late winter (March and April) by
NASA’s Operation IceBridge (OIB) mission. A total of 74 OIB flights
between 2010 and 2018 surveyed tens of thousands of kilometers of sea
ice, providing observations of pressure ridges at a higher spatial and
temporal resolution than previous airborne studies. Here we utilize
Digital Mapping System (DMS) imagery to identify shadows cast by
pressure ridge sails and, then, use these shadows to derive sail height.
Over 64,000 DMS images were analyzed, allowing for more than 33 million
individual sail height measurements to be calculated. We present the
full sail-height distributions of new pressure ridges recently formed
across a range of ice conditions on first-year (FYI) and multiyear ice
(MYI), and we assess year-to-year variability. We find distinct
characteristics depending on the ice type in which the pressure ridge
formed. The mean and standard deviation of sail heights on FYI is
~20-30 cm lower than those formed on MYI. Maximum sail
heights on FYI are ~1.5 m lower on average. Arctic sea
ice is getting younger, shifting from predominantly MYI to predominantly
FYI. Our results may inform new model parameterizations of pressure
ridges on sea ice in the changing Arctic, thereby supporting advances in
sea ice forecasting.