Dynamics of Earth and Ocean Systems (DEOS)
John A. Orcutt, Director
Cecil and Ida Green Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
La Jolla, CA 92093
Robert S. Detrick, Chair
Department of Geology and Geophysics
Woods Hole Oceanographic Institution
Woods Hole, MA 02543

Bandwidth/PowerCost

For more than a century oceanography has advanced rapidly through the mechanism ofoceanographic expeditions aboard ships. This tradition extends back at least to Darwin’s sailing on
HMS Beagle in an extraordinary voyage of discovery, which took him around the world during theyears 1831-1836.
Subsequent expeditions
such as that aboard HMS
Plate Scale - NEPTUNE
Challenger in 1872-1876• Fiber Optic cabledadvanced this use of• Significant seafloor powerships for understanding
Global Network - Buoys
the oceans. In the U.S.,• Long time series
the advent of the Office• High bandwidth telemetry/seafloor powerof Naval Research (ONR)
Relocatable Moored Buoyin 1946 and the formation• Comparative studiesof the National Science• Low bandwidth telemetry/No seafloor power
Foundation (NSF) in1950 led to a rapid
Figure 1: Technological solutions within DEOS.
expansion in the availability of oceanographic vessels for
conducting research at sea. Today 28 ships comprise theacademic fleet under the coordination of UNOLS.
Conservatively, this represents an investment of more than
$500,000,000 in the pursuit of basic research in the oceans.
The total US investment in the infrastructure for
expeditionary oceanography easily exceeds $1B. This
investment has led to major discoveries about the ocean and,as a scientific community, we can look forward to many
more decades of scientific advances. There are tasks,
however, for which the expeditionary approach is not wellsuited and which require major investments of a different
kind.
Expeditions to sea concentrate on a particular point or
portion of the oceans for a limited period of time.
Expeditions, because of this brevity in both space and time
are poorly suited for observing change. A permanent

Figure 2: The NEPTUNE installation

Measurements
Air-Sea Interaction &Meteorology

Geomagnetism

Oceanography

Still Photographs

Hydroacoustics

Video

Acoustic
Thermometry

AUV dataSeismology

Chemistry

Seafloor Geodesy

Biology

Table 1: Potential time-series observations at fixedlocations.

presence in the oceans is essential forgathering data to address a majorclass of scientific problems. Suchobservatories, while common on thecontinents, are rare in the oceans.
These observatories, with the ability
to provide power to the water column
and the seafloor, and telemeter data toscientists ashore in real-time, areimportant for the observation oftransients. There are also cases inwhich the signals of oceanographic
phenomena are sufficiently small thatlong time series are needed to raise
the signal-to-noise ratio to a level thatis scientifically useful. For example,
tomographic studies of the interior of
the Earth require thousands ofearthquakes recorded with goodsignal-to-noise ratio to define small
variations in velocity. In comingyears, requirements for the collectionof long time series in the oceans will
require investments which arecomparable to those we have alreadymade in oceanographic ships. It must

be appreciated, however, that theadvent of time series collection in
the oceans on a large scale will
only increase the need for ships
at sea. New kinds of ships,
which are well-suited formaintenance of the observatories,
will be needed; ships thatarewell-suited for operating large
remotely operated vehicles(ROV) and with the handlinggear and space for large
moorings.
Recently, the NSF has initiated aMajor Research Equipment(MRE) program to fund a
program in ocean observatories,
and the program has been
approved by the National Science

Figure 3: A mid-ocean global observatory with a variety ofsensors for geophysical and oceanographic applications.

Figure 4: The TAO array installed in the equatorial Pacific for monitoring the development of ElNiño.
Board. The Consortium for Ocean Research and Education (CORE) has established, with NSF
funding, an Ocean Observatories Standing Committee (OOSC) to undertake planning for theimplementation of a program for ocean observations with a funding profile in excess of $100M overa five year period. In the last several years
DEOS concentrated on two aspects of timeseries data collection: tectonic plate scale andglobal observatories. The new Standing
Committee adds coastal observatories to thismix to integrate global planning under a single
community organization. However, this paper
will concentrate on the aspects of time series
collection which affect the plate-scale andglobal observatories - the work done by
DEOS.
Within DEOS planning, there are three
approaches to technical systems for thecollection of data as shown in Figure 1. At theFigure 5: Shallow water temperature from TAO
top of the bandwidth/power pyramid areand surface height from Topex/Poseidon.
cabled systems such as that proposed by
NEPTUNE (Figure 2) with virtually unlimited
power (> 500 kW) and bandwidth (>10 Gbps). At the bottom of the pyramid are relocatablemoorings with low bandwidth telemetry (5 MB/day) and no power to the seafloor. The middle
ground is represented by moorings capable of delivering 500W to the seafloor and continuously
telemetering data at 64-128 kbps (Figure 3). While it might be anticipated that intermediate systems
with capabilities lying between the two buoy types can be realized by simply metering the funds
available, engineering studies have shown that this is not the case. These three classes ofobservatories represent the specific approaches available for exploring the oceans in time.
The collection of time series data in the oceans, while rare, is not unheard of. During the 40’s andinto the early 70’s Ocean Weather Stations (OWS) were deployed to provide ocean observations ofweather conditions for aircraft routing in the northern Atlantic and Pacific Oceans. Satellite
observations eventually eliminated the need for these manned ships although at least two of thesestations (S in the Atlantic and P in thePacific) continue to be occupied byunattended moorings for collecting
scientific data. The best modernexample is the TAO array of moorings(Figure 4) in the equatorial Pacific. This
array was begun with sponsorship, as ascientific program, by the NSF.
However, the moorings are now
maintained by the National
Oceanographic and Atmospheric
Administration (NOAA). The moorings
recently proved their worth in detecting
the formation of an El Niño event(Figure 5). The buoys (Figure 6) aresimple structures with very limited
satellite data telemetry and power
derived largely from batteries.
Large portions of the ocean basins are
distant from the nearest land – continents
or islands. For example, Figure 7 shows
all existing broadband seismographic
observatories in operation with 2000 km
radius circles drawn around them. Large
portions of the oceans lie outside thisFigure 6: An Atlas buoy as used in the TAO array.
network and understanding of theinterior of the Earth, the nature offaulting, and the ability to monitor
explosions suffer as a result. The Incorporated Research Institutions for Seismology (IRIS) begannearly 15 years ago witha goal of covering
Earth’s surface with auniform density ofseismic observatories the circled stations showthat the goal will not berealized until many (20 25) sites are occupied on
the seafloor.
There are a broad set ofoceanographic
measurements which canand must be made from
Figure 7: All existing broadband global stations in operation with 2000
fixed platforms
km circles around each.
(Eulerian vis-a-vis

Lagrangian) and many are
shown in Table 1.
Observations in physicaloceanography are particularlydependent upon suchplatforms.
The Global Ocean
Observations System(GOOS) and CLIVAR haveformed a timeseries group forpromoting observations atfixed sites. This timeseriesgroup has crossFigure 8: Global locations for proposed Global Eulerian Observarepresentation with the NSF
tories (GEO) timeseries stations.
ocean observatories steeringcommittee. Thetimeseries group is
promoting a series ofGlobal EulerianObservatories (GEO),
many of which are colocated with DEOS sites(Figure 8). Anotheroceanographic
application for DEOS isacoustic thermometry
which uses low-power
Figure 9: A potential configuration of acoustic thermometry stations
acoustic sources tointegrating both DEOS and GEO moorings.
measure travel times
and, hence, averagetemperature profiles on an ocean basin scale. A hypothetical network of thermometry stations isshown in Figure 9 making use of both DEOS and GEO sites. While the data available fromoceanographic observations from ships and satellites has grown exponentially over the past decade,the speed at which ships travel today has not changed significantly since the HMS Beagle!
Acoustics, with waves that travel at 1500 m/s, must be used to observe and integrate ocean
observations in coming years in many fields.
One of the greatest challenges in oceanography is the observation of geophysical and oceanographic
phenomena in the Southern Ocean. This ocean is critical to life on Earth, and observations of its
climate are needed to understand Earth’s deep interior. A suitable challenge for DEOS is to ensurethat we are able, through improvements in mooring design, seamanship, and ship capabilities, toestablish the first mooring in this inhospitable part of the world in a decade’s time.