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
Global ocean conveyor belt circulation
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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.
Argo Floats
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Profile 0 - 2000 m temperature,
salinity and pressure
Cost: ~$25K per float
Average lifetime: ~4 years
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Cannot monitor deep ocean
Cannot work under sea ice
Cannot work for water < 2000m
Still sparse
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
Cold water sinks
and spreads
across the ocean
floor.
National Snow and Ice Center
Monitoring climate change
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.
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.
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
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.
Repeaters
Instruments inside, outside
hard wire/fiber/inductive
New Technical Developments
Telecom
Science
• Dualconductor cable
featuring two
independent
conductors,
• Four-cable
branch unit with
two functionally
independent
cables.
Kordahi, 2010
Examples of seafloor cabled
observatories
Past example – Cable re-use
Seismometer Integrated into Submarine Cable
ARENA observatory, JAMSTEC
Cable re-use – HAW2
H2O seismometer lowered into hole dug by ROV JASON
Butler, Duennebier and Chave, 1999-2003
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
MARS Cabled Ocean Observatory off Monterey
Purpose built - MARS > US$12M
Comms for oil platforms
Courtesy of ODI (Flynn, 2010)
Summary
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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.
References
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Yuzhu You, Harnessing telecoms cables for science, Nature, 466, 690691, 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.
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.