Analysis of ICESat-2 Data Acquisition Algorithm Parameter Enhancements
to Improve Worldwide Bathymetric Coverage
Abstract
A major advance in global bathymetric observation occurred in 2018 with
the launch of NASA’s ICESat-2 satellite, carrying a green-wavelength,
photon-counting lidar, the Advanced Topographic Laser Altimeter System
(ATLAS). Although bathymetric measurement was not initially a design
goal for the mission, pre- and post-launch studies revealed ATLAS’s
notable bathymetric mapping capability. ICESat-2 bathymetry has been
used to support a wide range of coastal and nearshore science
objectives. However, analysis of ICESat-2 bathymetry in numerous
locations around the world revealed instances of missing or clipped
bathymetry in areas where bathymetric measurement should be feasible.
These missing data were due to the ATLAS receiver algorithms not being
optimized for bathymetry capture. To address this, two updates have been
made to ICESat-2’s receiver algorithm parameters with the goal of
increasing the area for which ICESat-2 can provide bathymetry. This
paper details the parameter changes and presents the results of a
two-phased study designed to investigate ICESat-2’s bathymetry
enhancements at both local and global scales. The results of both phases
confirm that the new parameters achieved the intended goal of increasing
the amount of bathymetry provided by ICESat-2. The site-specific phase
demonstrates the ability to fill critical bathymetric data gaps in open
ocean and coastal settings. The global analysis shows that the area of
potential bathymetry approximately doubled, with 6.1 million km2 of new
area in which bathymetric measurements may be feasible. These
enhancements are anticipated to facilitate a range of science objectives
and close the gap between ICESat-2 bathymetry and offshore sonar data.