Using submarine communications networks to monitor the climate – an overview

1. Using submarine communications networks to monitor the climate – an overview John Yuzhu You Institute of Marine Science University of Sydney, Australia *Presented at Rome workshop “Submarine Cables for Ocean/Climate Monitoring and Disaster Warning: Science, Engineering, Business and Law” on 8-9 Sept 2011

2. Global ocean conveyor belt circulation • Oceans store more than 90% of the heat and 50 times as much carbon as the atmosphere • in our Earth climate system; • Ocean bottom waters are formed in the northern North Atlantic and around Antarctica; • Global warming causes polar bottom waters to be less capable of sinking, reducing their • capacity of heat and carbon storage.

3. Argo Floats Profile 0 - 2000 m temperature, salinity and pressure Cost: ~$25K per float Average lifetime: ~4 years • Cannot monitor deep ocean • Cannot work under sea ice • Cannot work for water < 2000m • Still sparse

4. Global Tsunami Warning System 5h 10h 15h • -50 DART buoys - Deep-ocean Assessment and Reporting of Tsunamis (cover only limited area of the oceans) • Costs high: US$250K per buoy, US$125K O&M/y excluding shiptime • Life span is 4 years (battery limit) • Availability < 70% • Failures: batteries, vandalism and harsh sea surface condition • Japan March 11 tsunami and NOAA prediction in travel hour; because of the lack of buoys in vast open North Pacific, accurate prediction, especially the amplitude of tsunami waves, is difficult

5. National Snow and Ice Center Cold water sinks and spreads across the ocean floor. Affected by global warming/melting of ice. The change in water properties, (e.g.,temperature and salinity), can be measured with sensors installed in/on the repeaters (optical amplifiers) of a submarine cable. Monitoring climate change

6. Global Submarine Cables + Cabled Ocean observing Three cables overlapped with dots mark dense repeaters at distances of about 50-150 km apart: Tropical Atlantic from Spain to the Caribbean (using about 100 repeaters) Subtropical North Pacific from Los Angles to Hong Kong (using about 200 repeaters) Sydney to Auckland and then to Los Angeles (using about 500 repeaters). • Global submarine cables (red lines) • Recent and planned cable ocean-current monitoring (blue stars) sea-bed observatories (dark blue stars), out-of-service cables for scientific reuse (yellow lines) and cable systems where ownership transfer to science has been discussed (dark blue lines). Base map from Global Marine Systems Ltd.

7. Nearly 30 years of submarine cable data illustrating Florida Current variability Florida Current Florida cable Less than 1% of the submarine cables is used for science

8. Global Submarine Cables + Cabled Ocean Observing - Repeaters Submarine cables repeaters (blue dots) are symbolically plotted overlapping the cables (in red). Actual number of repeaters is about 4 times more than that plotted with a distance of about 40-150 km apart. For example, a typical transpacific cable would contain about 200 repeaters. Tsunami buoys and ocean observatories are also plotted.

9. Repeaters Instruments inside, outside hard wire/fiber/inductive

10. New Technical Developments Telecom Science Dual-conductor cable featuring two independent conductors, Four-cable branch unit with two functionally independent cables. Kordahi, 2010

11. Examples of seafloor cabled observatories

12. Past example – Cable re-use Seismometer Integrated into Submarine Cable ARENA observatory, JAMSTEC

13. Cable re-use – HAW2 H2O seismometer lowered into hole dug by ROV JASON Butler, Duennebier and Chave, 1999-2003

14. Power and Internet 10 kV DC, 4 Gbps/node 800km backbone, 120km spur cables 5 Nodes, 12 Junction boxes 130 instruments/40 types/400+ sensors 170 cables (60km), 636 connectors Purpose built - NEPTUNE > US$140M

15. MARS Cabled Ocean Observatory off Monterey Purpose built - MARS > US$12M

16. Comms for oil platforms Courtesy of ODI (Flynn, 2010)

17. Summary • Telecommunication companies can and should play a major, active role in monitoring climate change • In the past, the business opportunity for multipurpose cables and repeaters was missed and should not be missed again • Currently, there is no low cost way to monitor bottom and abyssal water-masses • Submarine cables and repeaters can fill this gap • Facilitate use of retired and in-service cables for climate change monitoring • New generation of cables and repeaters accommodating climate monitoring is urgently needed for building a global network at low cost.

18. References • Yuzhu You, Harnessing telecoms cables for science, Nature, 466, 690-691, 2010 • Yuzhu You, Using submarine communication networks to monitor the climate, ITU-T Technology Watch Report #15, Geneva, 11 pp., 2010. • Yuzhu You, Telecom companies could help create global monitoring network, Sea Technology, November 2010, pp. 73.  • Yuzhu You, Multipurpose Submarine Cable Repeaters Required To Monitor Climate Change, SubTel Forum, 54, November 2010 • Maurice E. Kordahi, Dual-conductor cable and a four-cable branching unit meet evolving needs for transo-ceanic undersea cable networks, Sea Technology, 51, No. 7, 2010 • Yuzhu You and Bruce Howe, Turning submarine telecommunication cables into a real-time multi-purpose global climate change monitoring network,SENSORCOMM 2011: The fifth international conference on sensor technologies and applications, pp.184-190, ISBN: 978-1-61208-144-1.

19. Q&A Q.1 What is the cost to add sensors in the repeaters? The cost is about several millions to 10 million US dollars dependent upon the number of sensors to integrate and complexity of the sensors themselves. This non-recurring engineering cost is regarded as modest when amortized over thousands of units for many years to come. Q.2 Why the private companies would be interested to do that? It has a large business opportunity and huge profit potential. Currently, billions and hundreds of millions US dollars are spent each year in ocean/climate monitoring and disaster warning in the world. Most of the money (about 80%) is governmental funding/investment. A lot of the programs are costly, inefficient and unsustainable. Monitoring using a submarine cable can last long (a few decades) and economically much cheaper.