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2
Lessons from Existing
Ocean Observatories
Over the past 30 years oceanographers have gained valuable experi-
ence with a few pioneering ocean observatories (Appendix D). Some of
these have been "observatories of opportunity," in which systems built
for other purposes have been leveraged for research. One such program
was the network of ship-based Ocean Weather Stations (OWS), estab-
lished after World War II for the primary purpose of guiding ocean-
crossing aircraft, which ended in 1981. While on station, ships collected
oceanographic data that played an important role in early efforts to un-
derstand how the ocean has changed over time. In particular, data from
this program helped define the relationship between the ocean and the
atmosphere.
Another example of an "opportunistic" observatory is the Sound Sur-
veillance System (SOSUS), a classified system developed by the U.S. Navy
in the late 1950s to detect, track, and classify Russian submarines using
arrays of underwater hydrophores. SOSUS is a network of acoustic ar-
rays in which hydrophores are connected to a shore station by a subma-
rine cable. Since the end of the Cold War, oceanographers have been
provided limited access to the SOSUS network. Researchers with security
clearances have used the system for productive studies of mid-ocean ridge
volcanic-hydrothermal systems, marine mammals, and acoustic thermom-
etry. SOSUS has also provided the research community with engineering
know-how that will be relevant to any cabled network of ocean observa-
tories. However, SOSUS has also highlighted the national security con-
cerns that will be raised by observatories with similar capabilities.
28
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LESSONS FROM EXISTING OCEAN OBSERVATORIES
29
More recently, a small number of long-term measurement sites have
been established in both coastal settings and the open ocean using arrays
of moored buoys. One of the most successful deep-sea sites has been the
TAO array in the equatorial Pacific. Developed as part of the 10-year
international Tropical Ocean Global Atmosphere (TOGA) program (1985-
94), the TAO array enabled improved detection, understanding, and pre-
diction of E1 Nino events and provided essential data to further under-
standing of the E1 Nino Southern Oscillation. Other upper-ocean and
air-sea interaction observatory sites that have been established and main-
tained in recent years include the Bermuda Atlantic Time-series Station
(BATS), the Hawaii Ocean Time-series (HOT) program, and the European
Station for Time-series in the Canary Islands (ESTOC) (Appendix D).
A small number of cabled observatories have also been established in
coastal settings. One of the oldest is the Field Research Facility (FRF) off
Duck, North Carolina, established by the U.S. Army Corps of Engineers
(USAGE) in 1977. The FRF provided a unique infrastructure of cabled
observatory sensors, measurement platforms, and deployment vehicles
to support a wide variety of basic research studies of near-shore fluid and
sediment processes at an open-coast beach. The 1996 installation of the
Long-Term Ecological Underwater Observatory (LEO-15) in 15 m of wa-
ter off the New lersey coast pioneered the use of cabled observatory sys-
tems for multidisciplinary, integrated studies of meteorological, physical,
and biological processes on the continental shelf. In 2000, another cabled,
near-shore observatory was established off the south shore of Martha's
Vineyard. The Martha's Vineyard Coastal Observatory (MVCO) is being
used as a natural laboratory to study how winds, waves, and currents
affect the coastline and to monitor oceanic and atmospheric conditions.
The Hawaii Undersea Geo-Observatory (HUGO), the first submarine vol-
cano observatory, was installed at Loihi Volcano off Hawaii in 1997, using
a 47 km electro-optical cable donated by AT&T. The Hawaii-2 Observa-
tory (H20), a permanent deep-water geophysical research observatory,
was installed in 5000 m of water about halfway between Hawaii and
California in September 1998 on the retired Hawaii-2 telecommunications
cable (HAW-2~.
These observatories have not only demonstrated the significant po-
tential of observatory science but also have provided valuable lessons on
the installation, management, and operation of ocean observatories. These
lessons should be considered as plans are developed for the new genera-
tion of ocean observatories envisioned in the OOI. In this chapter some of
the 'lessons learned' for each of the implementation issues addressed in
Chapter 4 are briefly summarized.
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30
ENABLING OCEAN RESEARCH IN THE 2 lST CENTURY
PROGRAM MANAGEMENT
· Experience from existing observatories (e.g., LEO-15, FRF) indi-
cates that observatories must be under the control of their users, the re-
search scientists, to provide maximum innovation and flexibility. Experi-
ment prioritization should be controlled by scientific requirements and
resource availability.
· A successful observatory program including well-balanced sci-
ence priorities, development goals, and operational needs requires con-
stant communication among scientists, engineers, and managers (e.g.,
TAO, BATS, HOT, FRF).
· Existing observatories (e.g., FRF and LEO-15) have proven the
value of a broad-based, interdisciplinary approach to observatory research
and the need for early and continued involvement of the modeling com-
munity to ensure that data collected are of sufficient quality and quantity
to be of value to modeling efforts.
· Experience from almost every existing ocean observatory has
shown the difficulty of sustaining funding for the maintenance and op-
eration of long-term observations in a funding environment dominated
by short-term, two- to three-year grants.
SENSORS
1 tJ
· Sensors appropriate for observatory use must maintain their cali-
bration and sensitivity characteristics for long periods of time at least
six months to a year (so-called 'observatory-capable' sensors).
· Years of deploying open ocean (e.g., TAO, BATS, HOT) and coastal
moorings (e.g., FRF) have shown that degradation of sensors on surface
buoys (due to exposure, vandalism, or sea birds), and damage to sensors
in the upper ocean and shallow, coastal waters (due to biofouling, fish
bite, corrosion, ship collision, or fishing gear) are major problems that
must be addressed to reduce maintenance costs and improve the reliabil-
ity of observatory measurements (Figure 2-1~.
· Observatories such as LEO-15 and MVCO clearly indicate that ba-
sic suites of observations, too expensive for individual investigators to
gather, provide the essential scientific context for an observatory's effec-
tive use in research and need to be provided as part of the observatory
infrastructure.
· Results have shown that one of the greatest benefits of ocean obser-
vatories (e.g., FRF, HUGO, H20) is high-frequency, long-duration sam-
nlin~ that can delineate transient events such as frontal passage, harmful
.
algal blooms, volcanic eruptions, or severe storms.
· Experience demonstrates that the development of new in situ in-
strumentation for observatory use is a lengthy process requiring multiple
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LESSONS FROM EXISTING OCEAN OBSERVATORIES
31
FIGURE 2-1 This before-and-after picture shows the tremendous problem that
biofouling presents to the long-term deployment of instruments in the upper
ocean, especially in coastal regions. Figure courtesy of Richard lahnke, Skidaway
Institute of Oceanography.
cycles of design, field-testing, troubleshooting, and redesign before the
instruments become seaworthy enough to be used routinely.
· Moorings (e.g., the Bermuda Test Mooring-BTM) or cabled sea-
floor junction boxes (e.g., LEO-15 or FRF) should be easily accessible (close
to shore) for testing new technology and instrumentation. Such access can
greatly accelerate the pace of developing and proving new technology
and instrumentation, as well as providing a platform for establishing the
comparability of a new technique with older methods that are being
phased out.
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32
ENABLING OCEAN RESEARCH IN THE 2 lST CENTURY
CONSTRUCTION, INSTALLATION, AND TESTING
· Experience from the telecommunications industry and at research
observatories such as HUGO, LEO-15, and MVCO shows that securing
landing rights for a cable shore station, conducting various environmen-
tal assessments, and securing the necessary regulatory approvals from
local, state, and federal authorities, is extremely time consuming requir-
ing lead-times as long as two years. Using retired, in-place telecommuni-
cations cables and existing cable stations eliminates the need to go through
a lengthy permitting process.
· H20 and HUGO demonstrated that reuse of retired telecommuni-
cation cables for ocean research observatories is feasible. The principal
limitation is power, not bandwidth.
· Experience with HUGO and H20 has indicated that engineering
instrumentation should be installed on observatory nodes to provide key
feedback on infrastructure performance and design and to evaluate in-
strument performance.
· Experience at HUGO, H20, and FRF emphasizes the importance of
knowing seafloor properties and, in some settings of armoring or burying
of cables. HUGO failed six months after it was emplaced because of me-
chanical wear to unarmored cable lying on the rough volcanic terrain of
Loihi submarine volcano. Experiences at FRF demonstrated that strong
wave and current action on a cable lying on the seafloor can cause abra-
sion of the cable as well as strain on junction boxes, cable splices, and
sensor connectors (Figure 2-2~. A cable buried even several meters can
become exposed following sediment movement.
· Several commercial firms are available for cable installation and
ocean hardware design and maintenance. The considerable experience of
these firms represents a valuable resource for observatory design and
installation (e.g., HUGO, H20) that the academic community should uti-
lize.
OPERATION AND MAINTENANCE
· The OWS, BATS, and HOT time-series sites showed that the value
of time-series data depends on the continuity and length of the record.
Ocean observatory systems and their instrumentation must be designed
for reliable, continuous operation and maintenance costs must be mini-
mized if these systems are to be operated for decades or longer.
· Observatory operations and maintenance (whether for moorings
or seafloor nodes) requires the availability of skilled and experienced
personnel. Availability of trained personnel to go to sea is an occasional
problem at present and will pose an even greater challenge for the ex-
panded observatory network envisioned by the OOI (e.g., FRF, TAO).
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LESSONS FROM EXISTING OCEAN OBSERVATORIES
33
FIGURE 2-2 Seafloor junction box at HUGO, atop Loihi Volcano off Hawaii,
after five years on the ocean floor. The partially buried package, recovered in
October of 2002, is still in excellent condition. Use of titanium and plastics has
virtually eliminated corrosion problems. Figure courtesy of Fred Duennebier,
University of Hawaii.
· Coastal observatories are most beneficial when an inventory of
community coastal vehicles (e.g., skiffs, surf zone working platforms, etc.),
are available on site for deployment and retrieval of sensors (e.g., FRF)
(Figure 2-3~.
· Surface observatory nodes require regular routine servicing to re-
place or repair system components and instrumentation and to maintain
data quality and continuity. Experience shows that these maintenance
costs are often initially significantly underestimated (e.g., LEO-15, FRF).
· Even with the few open-ocean observatories currently in opera-
tion, the limited availability of ships and ROVs has hampered their opera-
tion and maintenance (HUGO and Hem. These assets are in high de-
mand and scheduled well in advance, making it extremely difficult to
respond quickly to observatory failures. The future need for ROV assets
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34
ENABLING OCEAN RESEARCH IN THE 2 lST CENTURY
FIGURE 2-3 The USACE FRF's Coastal Research Amphibious Buggy (CRAB).
This deployment and retrieval platform is a tower on three wheels, hydraulically
driven by a diesel engine located on the operations platform, 11 m above the
seabed. The CRAB can operate in 2 m high breaking waves in 10 m depth of
water, with Global Positioning System (GPS)-positioning accuracy to deploy flu-
id- and sediment-boundary layer sensors. The CRAB has also been used to mea-
sure monthly bathymetric changes at the Duck, NC site over the past 25 years.
Figure courtesy of loan Oltman-Shay, Northwest Research Associates, Inc.
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LESSONS FROM EXISTING OCEAN OBSERVATORIES
35
will likely increase significantly as more ocean observatories are estab-
lished.
· Experience from years of operating oceanographic moorings shows
that inter-comparison and inter-calibration procedures are essential. These
procedures ensure data are of uniform quality even though they are col-
lected from diverse sites using different instruments. Ship and/or ROV
time must be dedicated to in situ sensor performance checks just before
and just after deployment, as well as on recovery; a requirement which is
often overlooked.
NATIONAL SECURITY
· One lesson from the U.S. Navy's SOSUS array is that the acquisi-
tion and public distribution of acoustic and other geophysical data in
some regions along the U.S. coastline poses a significant national security
risk. Deploying sensitive arrays in some areas could lead to the need to
restrict data access, prevent data acquisition at random intervals, or re-
strict publication of results.
DATA MANAGEMENT
· Other major ocean science programs such as RIDGE, the World
Ocean Circulation Experiment (WOCE ), and the Joint Global Ocean Flux
Study (IGOFS) show that the ocean observatory program cannot rely on
individual investigators to manage, archive, or disseminate observatory
data. Instead, data must be professionally managed and distributed
through established data centers according to a policy that guarantees
data is made available to the science community.
· Experience has demonstrated the value of establishing data for-
mats and metadata content among participating data centers during the
design phase of an observatory before data collection begins. For example,
H20 data is distributed in the Standard for the Exchange of Earthquake
Data (SEED) format, making it particularly valuable to seismologists
around the world.
· Major ocean science programs like RIDGE, WOCE, and JGOFS in-
dicate that strong interaction between science teams and data manage-
ment groups is essential for a data management system. Without this
interaction, requirements are often not implemented as intended.
· Instrument interfaces and data formats should be compatible
amongst various instruments to simplify their integration. A standard-
ized interface that would automatically associate an instrument's meta-
data with its data stream would facilitate such integration.
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ENABLING OCEAN RESEARCH IN THE 2 lST CENTURY
· Considering the large data acquisition rates (e.g., Gb/s to Tb/s),
and the complexity of data products that an ocean observatory network
could produce, levels of data products need to be defined and standard-
ized for sharing data. For instance, both satellite missions and Argo define
multiple levels of data products.
· Data archive centers require sustained funding to support data
archival and distribution, even after the life of a program. For example,
the Incorporated Research Institutes for Seismology's (IRIS) Data Man-
agement System archives approximately 3.5 Tb per year of seismic wave-
form data and is funded at about $3.5 million annually. In addition, NASA
maintains three major archive centers and one long-term backup center at
a cost of close to $100 million a year.
EDUCATION AND PUBLIC OUTREACH
· Experience has shown that education and outreach efforts will be
more successful and more cost-effective if they are part of the initial ob-
servatory design rather than an afterthought.
· As illustrated by experience with H20, outreach is best if handled
at a central facility (in this case, IRIS) than by individual investigators.
· NASA has shown that a successful education and outreach pro-
gram requires a professional staff with expertise in education and out-
reach. These activities need to be coordinated at the program level, not at
the individual investigator level. In addition, a mandatory percentage of
every project budget should be earmarked to support education and out-
reach activities.
Representative terms from entire chapter:
existing ocean
