Abstract
ICESat-2 (IS2), launched in September 2018, has been providing
high-resolution measurements of Arctic sea ice for two years. IS2’s main
instrument, the Advanced Topographic Laser Altimeter System (ATLAS), is
a photon-counting lidar with a pulse frequency of 10 kHz, translating to
0.7 m along-track sampling. We use high-resolution ATLAS measurements
with a new algorithm, to derive sea ice surface elevations for all
available IS2 reference ground tracks over sea ice for the 2019-2020
winter period. Sea ice surface elevations are used to calculate sea ice
parameters including surface roughness, ridge sail height, and ridge
frequency for the period October 2019 to April 2020. Near coincident
Airborne Topographic Mapper (ATM) lidar data were collected along IS2
orbits during the Spring 2019 NASA Operation IceBridge flight campaign.
Using ATM data as a validation tool, we show that, when compared to the
existing ATL07 sea ice surface height product, our algorithm discerns
pressure ridge frequency and height more accurately while maintaining
measurement precision at under 2 cm. We show monthly variability in the
probability distributions for these sea ice parameters, with respect to
ice type. Following our previous studies, we show that pressure ridges
have distinct characteristics depending on the ice type in which the
ridge was formed. These results demonstrate the utility of
photon-counting lidar for deriving new parameterizations of sea ice
surface roughness, ridge sail height, and ridge frequency, that may be
used to advance high-resolution sea ice modeling.