Enabling Ocean Research in the 21st Century Implementation of a Network of Ocean Observatories (2003) / Chapter Skim
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3 Status of Planning for Proposed Research-Oriented Ocean Observatories
3 Status of Planning for Proposed Research-Oriented Ocean Observatories
Pages 37-71
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From page 37... ...
GLOBAL OBSERVATORY PLANNING Global observatory science can be loosely divided into two categories, according to whether the data are obtained from the seafloor or the water column and sea surface. Data from the seafloor include geophysical information about earthquakes and the structure of the Earth, investigations of volcanic and tectonic activity, and studies of life on or below the seafloor.
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From page 38... ...
This network will complement and enhance other international global observatory efforts (see Chapter 6~. The following discussion summarizes the status of scientific planning and technical development for the OOI global observatory network.
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From page 39... ...
The DEOS Steering Committee has used the work of the TSST to identify preliminary locations for 20 moored-buoy observatories that could comprise the global network component of the OOI (Figure 3-1, Table 3-1~. The criteria for selecting these sites are outlined in the DEOS Global Network Implementation Plan (DEOS Moored Buoy Observatory Working Group, 2003~.
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From page 40... ...
East Pacific Rise RIDGE ISS site; tropical air-sea coupling, surface meteorology, water column, seafloor biology, hydrothermal vents, geophysics.
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From page 41... ...
47 S 142E South of Tasmania; meteorology, physical, biogeochemical, geophysics. SOURCES: Modified from Figure 1, DEOS Moored Buoy Observatory Working Group, 2003 and data from R
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From page 42... ...
42 o be o o au V)
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From page 43... ...
The opportunity to re-use retired telecommunication cables for some of these sites should be thoroughly investigated, however, as it might offer a cost-effective alternative to moored buoy systems in some locations. Moored Buoys At present, well-instrumented moored observatories using surface buoys are operational at tropical and mid-latitude sites (e.g., TAO, BATS, and the Pilot Research Moored Array in the Tropical Atlantic PIRATE.
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From page 44... ...
(DEOS Moored Buoy Observatory Working Group, 2000~. The first option is a cable-linked, high-bandwidth spar or discus buoy that uses an EOM cable to connect seafloor and moored instruments to the surface (Figure 3-2~.
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From page 45... ...
The following discussion offers an assessment of the technical readiness of each of these systems based on the recent DEOS Global Network Implementation Plan (DEOS Moored Buoy Observatory Working Group, 2003)
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From page 46... ...
Top: A low-bandwidth discus buoy system uses acoustic modems to transfer data intermittently from instruments on the seafloor or mooring to a surface buoy and from surface to shore via a low-power, omni-directional satellite system. Bottom: a high-bandwidth moored observatory that uses an electro-optical cable to deliver power and two-way data communication to a seafloor junction box and is linked to shore via a 64 kb/s C-Band satellite telemetry system.
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From page 47... ...
the maximum horizontal distance from the surface buoy at which a useful acoustic communication link can be maintained. Low-bandwidth, EOM-cab/e-/inked system The primary difference between this design and the other low-bandwidth system is that an EOM cable, rather than an acoustic-link, is used both to provide two-way communication to a seafloor junction box, and to provide small amounts of power (20 W)
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From page 48... ...
The seafloor junction box Both the low- and high-bandwidth EOM-cable-linked systems require a seafloor junction box between the various instrument systems and the EOM cable to the surface. The moored-buoy junction box should be designed to appear to the user as identical to the cabled observatory junction box.
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From page 49... ...
These tests include (1) deployment of a mooring to verify dynamic modeling of the mooring and to verify the survivability of an EOM cable that delivers power and communications to benthic and water column networked instruments, (2)
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From page 50... ...
Cabled Systems Planning for cabled observatories in the remote oceans began with meetings in Honolulu, Hawaii in 1990 to discuss the use of retired telecommunications cables (shave et al., 1990) , and in La Tolla, California in 1995 to plan for permanent ocean observatories (Purdy and Orcutt, 1995~.
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From page 51... ...
In fact, the high cost of new cable and cable ships was believed to limit the use of cables for observatories to near shore observatories; the development of the OOI reflects this history. Using submarine optical cable systems at global observatory sites is advantageous, given: · their high data bandwidth available for data transmission (250 Mb/s or more)
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From page 52... ...
There are a number of technical, logistical, and financial issues that need to be evaluated in order to determine the suitability of using retired cables for any particular global observatory site. However, in those cases where cables can be used in-place or moved only a short distance while still utilizing the original shore station, submarine cables potentially offer many advantages over the use of buoys or laying new cable.
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From page 53... ...
· the ability to produce appropriate hardware and software for use of these systems for observatories; Logistica/ · the problems surrounding the cooperation of foreign countries with established power and communications infrastructure, required to establish cabled observatories in remote areas;
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From page 54... ...
54 Financia/ ENABLING OCEAN RESEARCH IN THE 2 lST CENTURY · moving long sections of cable will require a commercial cable ship and experts to handle and terminate the recovered cable. The adequacy of the benefits of making high-bandwidth and power available to observatories in remote areas in offsetting the costs of the commercial cable ship and experts to handle and terminate the recovered cable in order to move long sections; · the affordability of shoring these cables, which will require armored cable and cable burial in many cases; and · the possibility of using spare cable equipment and cable that will also be discarded by the telecommunications industry for future observatories, and any attendant liabilities.
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From page 55... ...
Assessment of implementation readiness for a regional-scale cabled observatory requires consideration of the maturity of planning for identified scientific opportunities, as well as the extent to which technical challenges have been met or are likely to be met in the near future. Status of Scientific Planning The often unique scientific opportunities presented by high temporal resolution, long-term ocean measurements that can be provided only by cabled observatories have been extensively documented as a result of various broad-based community workshops and a series of recent reports (See Appendix C)
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From page 56... ...
A regional-scale observatory will complement the global observatory network, providing the higher temporal and spatial resolution data necessary to interpret the global-scale data for each of the interdisciplinary science questions listed above. Although the general scientific rationales for a regional-scale observatory can be considered as firmly established by the reports referenced above, detailed planning is just beginning for those specific, rather than thematic, scientific objectives that are crucially dependent on cabled infrastructure.
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From page 57... ...
The design and implementation of such a complex system of sub-sea cabled observatories pose many additional technical challenges (NEPTUNE Phase 1 Partners, 2000~. The commercial submarine telecommunications industry focuses on moving data from one shore landing to another.
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From page 58... ...
The first option is based on the conclusion of the 2000 U.S. NEPTUNE Feasibility Study that neither AC power nor the constant current serial DC power systems used in transoceanic telecommunications cables are appropriate for a submarine cabled observatory (NEPTUNE Phase 1 Partners, 2000~.
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From page 59... ...
STATUS OF PLANNING FOR PROPOSED RESEARCH-OR/ENTED OBSERVATORIES 59 FIGURE 3-4 Backbone cable structure and primary seafloor nodes proposed for NEPTUNE, an international USA-Canada sub-sea observatory spanning the Juan de Fuca plate off the western coasts of British Columbia, Washington, and Oregon. Figure courtesy of the NEPTUNE Project (www.neptune.washington.edu)
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From page 60... ...
NEPTUNE Feasibility Study, which was based on the assumption that a new, custom-designed cable would be laid, concluded that the two-way communication and interactivity requirements of a cabled scientific research observatory would be best met by extending the Internet into the deep sea (NEPTUNE Phase 1 Partners, 2000~. Under NSF support, WHOI, in collaboration with Cisco Systems, has been developing a Gigabit Ethernet system that will provide the communications for a multi-node, cabled observatory.
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From page 61... ...
Major additional challenges faced by regional cabled observatories lie in the heterogeneous data types that will be generated from a wide variety of instrument suites and the need to support simultaneous execution of many experiments. Valuable experience will be provided by a prototype based on this design study and scheduled for implementation during 2003-2004 as the DMAS for VENUS, a funded Canadian testbed observatory.
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From page 62... ...
It is widely recognized that technical challenges are best met through testbed sites, a sequence of cabled systems that will build the experience necessary to attain the full potential of a regional cabled observatory. Two testbed systems are presently under development in support of the eventual establishment of regional-scale undersea observatories.
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From page 63... ...
Monterey Accelerated Research System Funded through MBARI by the NSF and the David and Lucite Packard Foundation, MARS will involve the installation of a cabled test bed adjacent to Monterey Canyon in Monterey Bay, California (more information available at: www.mbari.org/mars/~. Planned for installation in early 2005, MARS will extend the VENUS experience to longer cable runs (62 km)
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From page 64... ...
scales that affect coastal processes. There is a community consensus that traditional monitoring strategies are inadequate for studying many coastal processes of increasing societal relevance (Thornton et al., 2000; Jahnke et al., 2002~.
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From page 65... ...
These approaches include relocatable arrays of moored buoys and radars (Pioneer Arrays) , cabled observatories, and fixed, long-term moorings (lahnke et al., 2002~.
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From page 66... ...
The motivation for such a relocatable observatory is to provide an infrastructure that is not permanently located at one geographic site, since coastal processes vary widely with location.
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From page 67... ...
The geographic flexibility of the Pioneer Array is analogous to a ship on station for several years, providing data from an array of 20-40 real-time coastal buoys and multi-static arrays of high-resolution coastal radars. Coupled with the output of other available remote sensors, the Pioneer Array would provide continuous coherent data streams that could be used by data-assimilation models.
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From page 68... ...
Like a Pioneer Array, cabled observatories can provide a test-bed for new instrumentation because they are easily serviced by small vessels and divers. The SCOTS report strongly advocates the use of cabled observatories for coastal research (Dickey and Glenn, 2003~.
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From page 69... ...
than is presently envisioned. If the coastal component of the OOI was restricted to Pioneer Arrays and cabled observatories as recommended by the CoOP FIGURE 3-5 Launch of fixed, long-term coastal mooring in Monterey Bay.
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From page 70... ...
In addition the community should play an active role in the design and implementation of IOOS in order to ensure that the placement and instrumentation of long-term coastal Sentinel moorings meet both the operational and research needs of the ocean community. Status of Technical and Engineering Development and Planning The technologies required for coastal surface and subsurface moorings and cabled coastal observatories are relatively mature and offer the OOI immediate scientific results.
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From page 71... ...
The potential of radar arrays has been demonstrated over the past five years, and the OOI would allow for the development and deployment of high-resolution multi-static arrays, ideal platforms for collecting coherent surface current data in coastal waters.
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