Vicki Ferrini

and 6 more

The Global Multi-Resolution Topography (GMRT) Synthesis is an elevation model that includes curated deep-water multibeam bathymetry data at ~100 m resolution covering more than 9% of the ocean. GMRT is built with a scalable tiled raster architecture that efficiently stores and presents high-resolution elevation data nested within low resolution data. A set of tools are available for users to access the compilation through simple user interfaces (e.g. GMRT MapTool) and web services, while also providing full attribution and access to source swath files. The availability of raw/unprocessed multibeam sonar data in the National Centers for Environmental Information (NCEI) archive has increased dramatically over the last decade, but transforming these data into high-quality integrated products suitable for use by scientists and the public alike requires significant effort. The GMRT Team has built workflows and tools for data preparation and review that are optimized for cleaning and integrating sparse globally distributed multibeam data, enabling the addition of ~60-80 research cruises per year. Once raw swath data files are cleaned and corrected, they are gridded/tiled with the GMRT Tiling tools so they can be reviewed and quality controlled in the context of other data in the GMRT Synthesis. Working with processed swath files generated by the community, we have observed that this process frequently reveals issues that are overlooked during data processing. In order to accelerate the rate of data integration and leverage the data processing efforts of the community, GMRT Tiling tools are being adapted for distributed use. Ocean Exploration Trust is an initial partner in this effort, and all processed swath files from the 2017-2019 Nautilus field seasons were prepared with GMRT Tiling tools and reviewed by the OET team. This revealed problems in processed swath data files from several cruises that were addressed prior to submission to NCEI, thereby improving the quality of data in the archive. We are now working to include the GMRT Tiling tools into at-sea standard operating procedures of the Nautilus as a testbed for broader community distribution, to ensure consistent quality of processed multibeam data, and to accelerate the production of high-quality integrated data products including GMRT and Seabed 2030.