SUBMARINE TELECOMS INDUSTRY REPORT – SECTION 7.2: SMART CABLES
The following section is provided by the Joint Task Force for SMART Cables. The Joint Task Force is composed of members from the International Telecommunication Union, the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization (UNESCO/IOC) and the World Meteorological Organization (WMO). This section was written by Bruce M. Howe, who is the Joint Task Force Chair as well as Professor and Chair of Ocean and Resources Engineering, University of Hawaii at Manoa. Science Monitoring And Reliable Telecommunications (SMART) cables are those cables that have additional environmental sensors added for the purposes of climate monitoring, tsunami warning systems or other research purposes.
Tsunamis crashing onto the shore, causing enormous damage and taking lives. Rising sea levels swallowing island and coastal communities. Warming oceans stirring up extreme weather and melting ice caps. Better monitoring and study of the deep oceans can help us better prepare for and mitigate all these issues, yet at present scientists and disaster managers have few ways to do so. That could all change, thanks to the submarine cables that already exist in the world today.
These cables crisscross oceans and seas worldwide, enabling global telecommunications. These cables are also in a perfect position to collect scientific data from the oceans in which they reside by serving as a “backbone” for environmental sensors that can be integrated into the cables. The sensors can then transmit the data to worldwide research centers, providing the world with data on tsunami and earthquake warnings, ocean temperature, and ocean bottom pressure.
For instance, earthquakes on the ocean floor can cause destructive tsunamis; the 2004 Boxing Day tsunami in the Indian Ocean caused billions of dollars of damage and over 240,000 fatalities. By integrating sensors into cable systems that can detect both the causal earthquake and the resulting tsunami wave while enabling the transmission of the sensor data to land-based early warning centers, managers can receive advance warning long before the resulting tsunami arrives on land.
False tsunami warnings pose their own problem. Since the U.S. tsunami warning system began in 1949, 75% of the evacuations of Hawaii’s coastlines have been unnecessary, with direct and indirect costs of millions or tens of millions of dollars per event. This is also true for other coastlines in the Pacific basin and elsewhere.
In addition to the benefits of tsunami warnings, sensors on cables can provide crucial data on ocean temperature and deep ocean circulation, both of which have global impact. Measurements of ocean bottom pressure—which provides information on the flow of water in the ocean—and temperature will help researchers understand and predict how sea levels will rise as the world warms and land ice melts into the oceans. These measurements will also contribute to a better understanding of ocean circulation patterns such as the deep currents transporting heat between the polar regions, which are now known to be a major cause of Antarctic ice melting.
The concept of integrating environmental sensors into commercial submarine telecommunications cables is called Science Monitoring And Reliable Telecommunications (SMART) cables—an initiative led by the Joint Task Force (JTF) sponsored by three United Nations agencies. Although the concept has existed in some form for several decades, the International Telecommunication Union (ITU), the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization (UNESCO/IOC), and the World Meteorological Organization (WMO) established the Joint Task Force (JTF) on SMART cables in late 2012.
JTF is now advancing the SMART cables initiative (see (Howe, et al., 2019)). This article will discuss the technical, financial, legal and implementation aspects of SMART cables as well as the work being done to bring the overall initiative to fruition.
7.2.2 SMART Fundamentals
The fundamental premise of SMART cables is integrating environmental sensors into commercial submarine telecommunications cables. The crucial objectives are: (a) to obtain long-term ocean bottom measurements of temperature (to measure climate trends), pressure (to capture sea level rise, ocean currents, and tsunamis) and seismic acceleration (for earthquake and tsunami warning, and seismology), (b) to have little or no impact on the operation of the telecommunications system that hosts the sensors, (c) to require no special handling or deployment methods, and (d) to be sufficiently reliable that 95% of all sensors operate for a minimum of 10 years with no maintenance.
SMART cables would make use of the global subsea fiber optic network. More than 1.2 million km of cable and 400 independent subsea cable systems all over the world are operated, maintained, and periodically renewed by the telecommunications industry. Although it is impractical to place sensors into deployed cables, sensors can be introduced during manufacturing into the repeaters on new cables (see Figure) during replacement or expansion operations, which occur on 10-25 year time scales. This provides the opportunity to introduce sensors on new cable systems on this time frame to slowly build an enduring, sustained ocean and earth observing network.
Figure. Repeater housing showing two possible sensor mounting locations: (a) on the end of repeater housing under the bell housing or (b) in an external pod. Seismic accelerometers are mounted inside the pressure housing (c).
7.2.3 Past to Present
The GeO-TOC system, installed in 1997 midway between Guam and Japan using the retired TPC-1 communications cable, anticipated the development of SMART cables by almost two decades yet included all essential SMART cable features: a three-axis accelerometer, pressure sensor, and precision thermometer. These were incorporated into an in-line pressure housing which was deployed from a cable ship in a conventional manner.
In the first decade of the 2000s, attention shifted to regional scale observatories such as NEPTUNE/ONC in Canada, DONET in Japan, and the OOI Regional Cabled Array (RCA) in the United States. Bespoke components were developed for interconnection, power delivery, and communications. Sensors are installed on separate platforms connected to the nodes using ROVs. Each of these employed commercial telecommunications cable and repeaters for the backbones.
Following the T?hoku earthquake and tsunami of 2011, Japan undertook rapid development of the S-net system incorporating many of the functions essential to a SMART cable, with 150 observation nodes along 5,700 km of cable divided into six independent subsystems (Kanazawa, et al., 2016). Each node has multiple sensors within, connected in-line with the telecommunications cable (but no telecom traffic, just data). The result provides evidence that SMART cables are close to being feasible using currently available technology.
Another in-line ocean bottom sensing system with pressure and acceleration was developed by the University of Tokyo (Shinohara, Yamada, Sakai, & Shiobara, 2016). In 2015, this was deployed off Sanriku with three nodes and a length of 105 km. This simpler and lower cost design was commercialized using an industry standard repeater housing; it could be adapted as an initial demonstration and/or be a starting model for a SMART repeater.
7.2.4 New Development
As described, many of the necessary SMART system attributes are already developed or “close”. More work needs to be done on high voltage isolation, serial add/drop communications, reduced size and power, sensor integration, and overall guaranteeing fail-safe operation of the repeater in the event sensor faults. These are very much surmountable engineering tasks, though all of must be done in a manner that is consistent with the 25-year expected operating life and 8,000-m deployment depth of a commercial repeater (Lentz & Howe, 2018). In the initial wet demonstration and/or pilot systems, requirements can be relaxed but the ultimate goal is to have system suppliers fully integrate SMART capability into their qualified proprietary designs, so a prospective buyer can simply check a box to select it as a system option; (Webster & Dawe, 2019), discuss this from a buyers perspective.
Successful operation of shorter SMART cables will be needed before sensor functions can be introduced into the longest cables. Regional systems with lengths of a few hundred km up to several thousand km are ideal for the inclusion of sensor capabilities because these systems have sufficient design margin and can usually accommodate additional fibers to carry sensor data. Ocean spanning cables of more than 6,000 km are more challenging and will be for the future.
Data from SMART cables are expected to be open and freely accessible. Data generated by SMART cable sensors will be transmitted to a shore station where it may be stored in raw form, processed, and transmitted onward to data repositories, national agencies, and academic institutions.
7.2.5 Legal Outlook
Because SMART cables combine science and telecommunications into a single cable, they do not fit neatly into existing international legal frameworks. SMART cable projects will be carried out in the exclusive economic zones of individual cooperating nations—the coastal regions of an individual nation over which the nation has legal jurisdiction—and the high seas. As the dual-use cables concept turns from development to deployment, the collective international understanding of their legal status will be refined based on concrete examples, routes, and uses.
JTF pilot projects are explicitly intended to validate the technology and business case for dual-purpose cables and create a climate where oceanographic sensor-enabled telecommunications cables are a recognized part of maritime infrastructure. In doing so, they will habituate the industry to such projects and reduce the perceived legal and business risk of this concept.
The submarine cable community can assist this process by developing specifications and standardized components to be included on telecommunications cables. This will provide all parties involved with a clear understanding of the capabilities of dual-purpose cables, thus reducing the potential for concerns by otherwise cooperative nations that such projects could stray from their stated scientific goals.
Based on a 10-year life cycle for cables (a quite conservative assumption), we calculate that an eventual steady state of 30 systems comprising 160 Mm of cables (4 times around the world), and 2000 SMART repeaters with sensors would cost $40M/year. This equates to 3 systems per year and 200 repeaters, with each repeater costing about $200K and $20K/year. By sharing the submarine cable infrastructure and associated costs with telecom, SMART cables can collect sustained, globally distributed, and fixed in space, ocean observation data.
With longer timelines and a broader range of goals, government-backed cables represent a good opportunity for SMART cables. For example, the Tsunami Act 2017 gives NOAA the responsibility to consider “…integration of tsunami sensors into Federal and commercial submarine telecommunication cables.” Early engagement with potential projects is important for ensuring that future cables’ configurations are compatible with SMART requirements and to arrange funding. Multilateral development banks are a possible source of funding, as they fund connectivity projects between developing countries as well as projects related to climate and disaster mitigation; they see the advantage of “two for the price of one.”
For comparison, the US NOAA DART Tsunami buoy program budget is $27M/year, comparable to the incremental cost for a SMART cable that spans the Pacific region where most of the US DART buoys are located. The Argo program, with 4,000 expendable floats, costs about $32M per year to maintain. The NSF funded OOI cost approximately $400M for the fabrication phase, with operating costs of approximately $44M annually. NOAA estimates it spends approximately $430M annually to operate and maintain its ocean, coastal, and Great Lakes observing systems.
7.2.7 Ongoing and Future Plans
The first deployment is anticipated to be a demonstration system that does not interface with the telecommunications portion of a cable, but instead focuses solely on sensor functionality. Off-the-shelf components may be used to reduce development costs, even if these are physically larger than would be for a fully developed SMART cable. The demonstration system could be deployed as a branch of a commercial cable system, connected to an existing cabled observatory, or reuse a portion of an out-of-service cable. The National Institute of Geophysics and Volcanology (INGV) obtained funding in June 2019 to deploy a wet demo on their Catania ocean observatory.
Following the demonstration system, full development of SMART-enabled repeaters must be undertaken by one or more system suppliers. The resulting repeater design will undergo qualification tests and sea trials after which it will be available for use in commercial telecom systems. An initial pilot system is being planned between New Caledonia and Vanuatu. It is explicitly SMART, 300-km long, with two repeaters. A majority of the required funding has been obtained as part of a French innovation project (Radio New Zealand, 2019). Additional funding is being sought.
After these confidence-building measures, deployment of a major SMART cable system will take place. A regional cable, ~2,000 km in length and containing ~20 repeaters, is ideal as it is manageable both in scope and cost. Successful operation on this scale will provide a conclusive demonstration of the value of SMART cables and ensure they have no impact on the telecommunications performance of the cable system. A system being proposed by ANACOM (Telecom regulatory agency, Portugal) connecting Lisbon-Azores-Madeira-Lisbon explicitly includes optical fiber sensing and SMART capability. Such a system will convert the currently “deaf, dumb and blind” cables into environmentally aware systems that can proactively mitigate man-made and natural hazards serving not just cable protection needs but important societal needs and development goals.
Indonesia is adopting SMART cables as an element of their cable-based tsunami warning system that is currently under design. In this case, the geographical extent of the Indonesian archipelago dictates sharing infrastructure and cost with telecom in order to obtain the necessary spatial coverage at an affordable cost.
Other cables with SMART/science capability are being considered: for cables along Latin America and in the Caribbean, and from Chile to Asia (the InterAmerican Development Bank is supporting efforts to include SMART capability) and even Antarctica; and across the Arctic Ocean.
As the phased implementation of SMART cables progresses, confidence will grow and deployment around the globe will become ubiquitous.
7.2.8 Concluding Remarks
We have presented an overview of the Joint Task Force (JTF) on SMART cables and its activities. The future will likely see ITU supporting this community with international standards (ITU-T Recommendations) to ensure interoperability and to reduce costs by using common specifications worldwide.
SMART cables are already technically feasible, and we are in the process of proving this via demonstration and pilot systems. Their estimated costs are similar to those of existing ocean observing systems. Their benefits to society are clear: in the short term, improved tsunami warning systems can save lives. In the long term, monitoring the ocean will help mitigate the effects of climate change. The submarine cable community has a chance to contribute with the JTF to this global effort by proactively supporting the effort, surmounting challenges as they arise, within the UN Decade of Ocean Science for Sustainable Development and taking action to advance societal goals within the UN Global Compact.
If we don’t act now, before we know it, we will be facing global temperature rises above 2 degrees Celsius and meters of sea level rise. There will be no turning back. These are real dangers that will forever change our world. There is no excuse for inaction.