Calculating Sea Ice Concentration with ICESat-2Sea ice concentration (SIC) is an essential parameter for climate models, informing our understanding of Earth’s changing cryosphere. Current SIC data relies on passive microwave (PM) sensors, which struggle to resolve small features like fractures in compacted sea ice. Modern laser altimetry, such as the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), is capable of decimeter-level elevation accuracy over a much smaller footprint than PM sensors. This allows for better precision in classifying overflown surfaces. This study examines a new SIC product from ICESat-2 based on the ATL07 sea ice height product. The ICESat-2 SIC estimates are then compared against PM SIC predictions from the National Snow and Ice Data Center and the Ocean and Sea Ice Satellite Application Facility. Idealized SIC calculations along the ICESat-2 tracks are compared with measured SIC data from ICESat-2. Multispectral products from the DigitalGlobe WorldView satellite constellation and the Moderate Resolution Imaging Spectroradiometer are used as ground-truth to assess the accuracy of SIC data from ICESat-2 and PM sensors. Focusing on the spring melt seasons of 2020 and 2021, we find ICESat-2 to be more accurate at measuring SIC for regions with 96-97% SIC than PM sensors. This study validates the viability of ICESat-2 to estimate SIC in regions of compact, but not fully-ice-covered areas.Yoosiri, PittayuthcreatorChristopher HorvatadvisorBrown University. Institute at Brown for Environment and SocietyInstitute at Brown for Environment and Societyresearch programSea iceRemote sensingOptical radarAltimeter--Data processingEnglishtext_resourcespostersriuProvidence, RIBrown University20221 posterborn digitalAll rights reservedIn CopyrightAll Rights Reserved10.26300/ekrp-5g51