SMART Cables for Observing the Global Ocean: Science and Implementation

Abstract

The ocean is key to understanding societal threats including climate change, sea level rise, ocean warming, tsunamis, and earthquakes. Because the ocean is difficult and costly to monitor, we lack fundamental data needed to adequately model, understand, and address these threats. One solution is to integrate sensors into future undersea telecommunications cables. This is the mission of the SMART subsea cables initiative (Science Monitoring And Reliable Telecommunications). SMART sensors would "piggyback" on the power and communications infrastructure of a million kilometers of undersea fiber optic cable and thousands of repeaters, creating the potential for seafloor-based global ocean observing at a modest incremental cost. Initial sensors would measure temperature, pressure, and seismic acceleration. The resulting data would address two critical scientific and societal issues: the longterm need for sustained climate-quality data from the under-sampled ocean (e.g., deep ocean temperature, sea level, and circulation), and the near-term need for improvements to global tsunami warning networks. A Joint Task Force (JTF) led by three UN agencies (ITU/WMO/UNESCO-IOC) is working to bring this initiative to fruition. This paper explores the ocean science and early warning improvements available

Toward Near‐Field Tsunami Forecasting Along the Cascadia Subduction Zone Using Rapid GNSS Source Models

“…However, it is important to note that for larger events as are tested here, the typical range for GNSS noise (between 2 and 5 cm) is much lower than the expected signal (Melgar et al, 2020). In addition to traditional on‐land GNSS, fully submarine data sets, such as pressure data from cabled networks, can provide key real‐time and direct tsunami information for earthquakes (Gusman et al, 2014; Heidarzadeh et al, 2019; Howe et al, 2019; Kanazawa et al, 2016; Maeda et al, 2015). This data can then be incorporated into geodetic and seismic assessments, providing high‐resolution models from trench to coastline, reducing some of the uncertainties common with geodetic models and highlighted above (Tsushima et al, 2014).…”

Observing the Oceans Acoustically

“…Judiciously locating cabled sources and using sources deployed from GO-SHIP vessels (providing sustained repeat hydrographic sections on decadal repeat timescales) can quickly provide wide-scale coherent tomographic coverage and derived heat content estimates, supplementing and complementing other, often incoherently sampled, observing elements. SMART telecommunication cables with integrated sensors will play a role as well (Howe et al, 2019).…”

The Importance of Marine Research Infrastructures in Capturing Processes and Impacts of Extreme Events

“…For near-field tsunamis, the reliable computation of the tsunami propagation and inundation may also take advantage of long-term operation of GPS buoys in shallower (<400 m) coastal waters, tide stations at the coasts and, most importantly, a series of national tsunami warning centers to process the data and inform local authorities who then notify the population (Barnard and Titov, 2015). The global coverage of marine sensors useful for tsunami hazard detection may also increase thanks to the ongoing Smart Cable Initiative, which is proposing to use telecommunication cables to densely disseminate devices on the ocean floor, thanks to cooperation with telecommunication companies (Howe et al, 2019).…”