An Assessment of Regional ICESat-2 Sea Level Trends

Global sea level rise is an important indicator of ongoing climate change and well observed by satellite radar altimetry. However, observations from conventional altimetry degrade at the coast where regional sea level changes can deviate from open ocean sea level changes. Tide gauges have historically filled this gap, providing important measurements of coastal sea level, but nevertheless undersampling dynamic coastal environments. With the launch of the laser altimeter onboard ICESat-2 in 2018, new high-resolution observations of ice, land, and ocean elevations are available. Here we assess the potential benefits of sea level measured by ICESat-2 by comparing to observations from Jason-3 and hourly tide gauges. We find agreement in the linear rates computed from the independent data sources. The recent La Niña is clearly evident in ICESat-2 observations, as well as small-scale features. By demonstrating the quality of the ICESat-2-measured sea level, we provide support for integrating it into the existing suite of sea-level observations. As the time-series lengthens in the coming years, it can serve as an important tool for coastal communities addressing ongoing sea-level rise.