The University of Hawai‘i Sea Level Center (UHSLC) ensures that water-level data from tide gauges around the world are collected, quality assessed, distributed, and archived for use in climate, oceanographic, ocean engineering, and geophysical research, as well as for operational purposes (e.g., tsunami and surge monitoring; satellite-altimeter drift monitoring; high-tide monitoring and forecasting). These GOMO-funded activities represent U.S. support for the international Global Sea Level Observing System (GLOSS), which operates under the auspices of the Joint Collaborative Board (JCB) between the World Meteorological Organization (WMO) and the Intergovernmental Oceanographic Commission (IOC).

The UHSLC operates 84 tide-gauge stations, including approximately 20% of the active stations in the GLOSS core network (GCN, Figure 1), which is a widely distributed set of research-grade tide-gauge stations that form the ‘backbone’ of the global in-situ water-level observing network. UHSLC involvement in the international network assures that research-quality data are available from otherwise sparsely sampled areas of the global ocean, and that developing nations have access to training, technical support, and data processing services as needed. Near-real-time data from stations operated by the UHSLC are essential for monitoring and modeling efforts undertaken by NOAA/NWS tsunami warning centers. The UHSLC also maintains 12 continuous GPS receivers co-located with tide-gauge stations due to the importance of accounting for land motion when using tide-gauge data for satellite altimeter validation, as well as documenting the contributions of land motion to local sea-level trends.

The UHSLC serves as a primary data assembly center in the GLOSS framework. UHSLC staff members coordinate monthly and yearly data collection from more than 60 international agencies to ensure that high-frequency data from over 500 globally distributed tide gauge stations flows continuously into the UHSLC data center. UHSLC databases focus on high-frequency tide gauge data that are essential for capturing the variability and impacts associated with tides, tsunamis, severe storm surges, and minor flooding episodes. A key benefit of having a data assembly center in a university setting is that UHSLC scientists actively utilize tide-gauge data for climate and oceanographic research, which provides ongoing assessments of data quality and develops new use cases for the data. The datasets are also widely used in the international research community with typically 50 to 100 peer-reviewed publications per year citing UHSLC datasets.