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.