Albert J. Williams 3rd et al.: Innovative Technology in Oceanography: Past, Present and Future 3

978-1-4673-0266-1/11/$26.00 ©2011 IEEE

Innovative Technology in Oceanography: Past, Present and Future

Albert J. Williams 3rd Woods Hole Oceanographic Institution, MS #12, 98 Water St.,

Woods Hole, Massachusetts, USA

Abstract: Technological innovation has provided oceanography with tools for observation, analysis and data sharing that increase the rate at which society can benefit from our understanding of the environment. While most of the innovations have come from outside oceanography such as electronics, the analog to digital revolution, microprocessors and the Internet, many have been invented by ocean engineers such as the CTD, underwater acoustic telemetry and autonomous underwater vehicles. The consequences of not having these tools would have been a vastly decreased observational base of data and information and consequent understanding of earth processes including climate change, ocean acidification and other phenomena of social concern. Fiscal concerns threaten innovation in oceanography as in other social activities. It is presumed that freezing technological innovation at the present stage will impede observations, analyses and understanding resulting in unwise policies on a global scale to social detriment for all mankind. The establishment in the IEEE/Oceanic Engineering Society of the Innovative Technology Committee in May 2011 has provided impetus for this paper.

1. Introduction Modern oceanographic methods may be dated to the Challenger Expedition of 1872–1876 [1] where concerted efforts were made to survey the world ocean for temperature, salinity, pelagic marine animals and benthic organisms plus sediments and rocks for geological purposes. But precise measurements of current, temperature and even depth were facilitated by technological developments during the latter part of the 19th century. Efficient bathymetric mapping resulted from echo sounding [2], a development much advanced by military concerns during the Second World War. This was one of the earliest

applications of electronics to oceanographic observing. Since then the rate of innovation has accelerated, in the US first from the post-WWII efforts of the Office of Naval Research and then stimulated by the Stratton Commission [3] with the establishment of the National Oceanic and Atmospheric Agency, NOAA. By the early 1950s, oceanographic science was not dependent solely on museum-funded expeditions and private research foundation grants but derived from the mostly more abundant federal funding of research. The author’s exposure to many of the developments in oceanographic technology is presented.

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2. Developments in Oceanographic Technology

Developments in technology that have benefited oceanography can be grouped into electronic, mechanical, communication, data handling and signal processing. These have almost entirely come from fields outside ocean engineering and have been driven by broad need and readiness of society for acceptance of these innovations.

2.1 Electronics Invention of the triode electron tube by Lee De Forest in 1907 [4] might be formally designated as the beginning of electronics. The use of this as an amplifier made radio practical and simplified the production of acoustic signals and their detection so that sonar became practical as well. Sonar was used to map bathymetry globally but the discovery of the mid-ocean ridge system awaited the use of echo sounders despite many deep measurements having been made by such devices as the Sigsbee wire-and-weight deep-ocean sounder [5]. Radar came along after WWII as well and aided ship safety permitting oceanographic voyages to be carried out with less risk. Radio began to be used for tracking buoys in the 1950s improving recovery rates and extending deployment times from days or weeks to months. However, electronics built inside instrumentation was slow to catch on and in 1969 when I arrived at Woods Hole Oceanographic Institution (WHOI), my mentor, Douglas Webb, told me that upon his arrival as an electrical engineer only a few years earlier there was an adage: “The value of an instrument varies inversely with the number of vacuum tubes in it”. Webb worked hard to reverse that attitude and, in 1969, transistors began to replace vacuum tubes in underwater electronics and the first integrated circuits appeared. The transistor had been invented in 1950 [6] and caught on rapidly with transistor radios. Transistors greatly reduced the heat generated in the early digital computers previously consisting of vacuum tubes. Finally, integrated circuits permitted the density of transistors and gates that made digital electronics reliable and compact.

2.1.1 Vector Averaging Current Meter and the Analog to Digital Revolution

One of the first beneficiaries of the digital revolution was the Vector Averaging Current Meter (VACM) being developed at WHOI when I arrived in 1969. It used the RCA COSMOS or Complementary Metal Oxide Semiconductor (CMOS) logic circuits when only about thirty kinds were available at the time that the VACM design was frozen. A special array for converting angle into sines and cosines was built for the VACM. In the wider world, TTL circuits were being used for digital devices because they were faster than CMOS. But as we soon found out in society, wasted power makes heat and, the required density of circuits in digital devices has largely moved them all to CMOS from TTL and other topologies. But in 1973, I heard an engineer from Boston state: “You guys at Woods Hole are in the dark ages with your use of CMOS for digital circuits.”

2.1.2 Microprocessors

A special flavor of CMOS integrated circuit was the digital microprocessor and RCA made the COSMAC microprocessor, the model 1802 [7]. It was such low power, only consuming current during actual state switching, that NASA adopted it for deep-space missions. About the time that the Boston engineer was criticizing us for using CMOS circuits for underwater instruments, the deep-space probes began to use them with their longer demonstrated reliability than shown by younger devices. Some are still flying today with model-1802 microprocessors or were several years ago. The promise of capabilities using microprocessors was realized by Frank Snodgrass at Scripps Institution of Oceanography in 1972. He dismantled the early Hewlett Packard HP35 pocket calculator to gain access to the CMOS processor inside since none were yet available commercially. He built transistor switches that effectively pushed the buttons. But then RCA started selling the model 1802 and Albert Bradley at WHOI designed an Autonomous Listening Station [8] around the 1802. All of the code was written in machine

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language because there were no assemblers available yet. Al taught me to write assembly code for the 1802 and it was compact and only did what you expected it to do because it wasn’t interpreted. But assemblers were soon provided and simplified the bookkeeping of addresses. I had built a CTD on a free vehicle with mostly transistor circuits but when I added a velocity sensor (still using transistor circuits) [9] the instrument grew more complex. A revision of what by then had become a Benthic Acoustic Stress Sensor (BASS) [10] to measure Reynolds Stress in the bottom boundary layer of the deep sea and shelf called for a transition from sets of serial shift registers using integrated circuits to the 1802 and I was forced to learn to program in machine language.

2.1.3 Data Storage

In 1969, the VACM was committed to use an improved method of data storage. Its predecessor, the Geodyne 850, used photographic film with spots (digital it must be said) exposed on the film, which when read told the number of Savonius rotor revolutions and the heading of the vane at the end of every recording interval, typically 15 minutes. But reading the film was painful and the recording was not very reliable. Other recording media were worse including pressure sensitive paper with a galvanometer needle pressed on the slowly moving paper by a clacker bar (Rustrak) and digital magnetic tape taken from the large 7-track tape drives used in computing centers but wrapped on a small spool. Sea-Data, Inc. was formed by Winfield Hill to produce the digital cassette tape recorder, shown in Figure 1, that he developed for the VACM and it became a sort of oceanographic industry standard, used by most of the electronic underwater instruments of the 1970s and even into the 1980s. Lon Hocker, originally working with Winfield Hill at Sea-Data, started his own company, Onset Computer and soon was producing a line of single board microcomputers based upon the Hitachi 6303 microprocessors [11] with RAM memory and these were more convenient to use for modest amounts of data to be logged in underwater instruments. They

were programmable in a kind of BASIC, interpreted as the instructions were executed, making reprogramming very easy. These Onset microcomputers were called Tattletales [12] from their original purpose of tracking the temperatures of refrigerated produce trucks to identify why the lettuce was spoiled in a cross-country trip. The Tattletale 6 was designed to use for memory the hard disk that had been newly developed for Personal Computers. Disk capacity rapidly grew, as we are well aware, from 20 MByte to 200 MByte (and continues to grow to Terabyte size). But the next development, this time from digital cameras, was the Compact Flash memory, static RAM and the Tattletale 8 with a Motorola 68332 microprocessor was capable of logging data to a CF card provided by Persistor [13], a spinoff company from Onset. CF cards are now available to Gigabyte size.

2.2 Mechanical The age of electronics has not quite been matched by extraordinary developments in mechanical systems but there are noteworthy things to comment upon. Some are peculiar to oceano- graphy.

2.2.1 Swallow Floats

Simple things like pressure vessels have benefited from a realization by John Swallow in 1950 that while pressure housings built of steel can barely float if designed for a 5000 m depth, a housing of aluminum can be so built due to its lower density and inherent stiffness. This permitted neutrally buoyant floats to be con- structed with compressibility less than seawater that would stably drift at a determined depth above the sea floor. These could be acoustically tracked to determine the motion of the water at the so-called “level of no motion”. The aluminum tubes that Swallow constructed required a thinner wall than was commercially available so he “milled” the tubes in a solution of sodium hydroxide, lye, in a wooden trough in his garden. The reaction of the sodium hydroxide with the aluminum evolved hydrogen

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gas, which John Swallow mischievously ignited. The liberated hydrogen burning with a blue flame creates an interesting image of this noted oceanographer doing alchemy in the evening. The Swallow floats, as these neutral drifters came to be called, demonstrated in the Aries experiment that the level of no motion had quite a bit of motion and led to the Mode and Polymode experiments that demonstrated the ocean is turbulent at a very large range of scales. It was soon realized that glass also can be used for Swallow floats [14] in both spherical and in cylindrical form. In the cylindrical form, Thomas H. Rossby developed the RAFOS floats that derive from the aluminum SOFAR floats of Doug Webb. Both of these are neutrally buoyant drifters but the SOFAR floats transmit low-frequency sound tracked from fixed listening stations while the RAFOS floats listen to sound transmitted from fixed sound transmitters. The success of these Swallow floats today cannot be overestimated. The world oceans are populated with over 3000 of the Webb ARGOS floats [15] that are tracked only by GPS when they periodically rise to the surface to report their position, temperature profile and sometimes other sensed properties of the water column before descending again to the depth where they drift between transmissions.

Fig. 1: The Sea-Data digital cassette recorder provided 11 million bits of non-volatile data storage in 1970, a boon to oceanographic instrumentation. Shown is a cassette tape transport adapted to shipboard logging of radio-transmitted data from a surface buoy cabled to a current meter array on the seafloor.

2.2.2 Crystal Oscillators

Another mechanical development includes crystal oscillators of various characteristics. One is the pressure sensor developed by John Paros consisting of a structure that changes its resonant frequency proportional to the imposed stress created by a Bourdon tube pressing on the crystal, which is exposed to ambient pressure [16]. Another is the zero temperature-coefficient cut of the crystal that is used as a stable frequency standard for timing. A third is the ultra-stable cut of the crystal with minimum aging characteristics. These were originally designed for temperature-controlled ovens. But controlling temperature in an oven requires a lot of power so Pierre Tillier, in his SeaScan clock, measured the temperature and adjusted the frequency to correct for the variation of frequency with temperature. The choices for two of these three cuts (the Paros cut doesn’t require compensation) have been to compensate for temperature in the low-temperature coefficient cut and to oven-control the temperature or to correct for the temperature coefficient of the crystal in the low-aging cut. The benefit of these precision crystal clocks has been precise determination of seismic arrival times in ocean bottom seismometers [17] and acoustic travel times between drifting instruments such as SOFAR floats and fixed listening stations to more accurately determine drift velocities. The most stringent demands on these clocks are for acoustic tomography where average temperature structure can be determined by measuring acoustic travel times over ocean basin scales. Ocean acoustic tomography [18] has given us some of the most sensitive deter- minations of deep-ocean warming.

2.2.3 Global Positioning System

Navigation at sea using a sextant, dependent for a precision of about 3 nautical miles upon William Harrison’s clocks, got a tremendous boost from first radio positioning systems such as LORAN and OMEGA and then from GPS satellites. What was formerly a question of visual sighting to locate a released mooring when it surfaced became almost routine, only currents in the water column adding uncertainty to the place where the released float should appear.

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2.2.4 Bathythermographs

The Bathythermograph (BT) [19] developed by Athelstan Spilhaus before WWII was considered valuable for determining speed of sound profiles in the upper 200 m of the ocean and determining acoustic shadow zones where submarines could hide from destroyers. The United States Navy had BTs and used them both from destroyers to hunt Japanese submarines and from US submarines to evade Japanese destroyers. The BT illustrated in Figure 2 used an evacuated Bourdon tube to move a stylus in one direction when external pressure caused the tube to flatten and curl inward and another fluid-filled tube to move the stylus in another direction when cooled by seawater at a lower temperature. The stylus left a trace on a smoked glass slide that could be read with a viewer to note the depth of each 2°C isotherm. The value of the BT, which was allowed to fall freely to about 200 m and then winched back to the deck from a ship underway at 6 m/s, was so great that it was replaced with an XBT, or Expendable Bathythermograph. The XBT is allowed to free fall and then break the wire transmitting the temperature signal back to the ship. XBTs have been augmented to XCTDs and XEMVPs that measure conductivity and temperature to obtain a full density profile and electromagnetic velocity profilers that measure the electric field produced by water currents in the earth’s magnetic field.

Fig. 2: The Bathythermograph or BT was streamlined to sink rapidly as a wire connected to the nose weight was paid out from the deck of a ship steaming at 6 m/s. The operator allowed it to sink as far as 200 m

before it was reeled back. A stylus etched temperature (from the coils of fine tubing) and pressure (from a Bourdon tube) onto a smoked glass slide that could be read after recovery.

2.2.5 Reversing Thermometers

Having described the BT, it must be explained that precise temperature and even precise pressure have been measured since about 1900 with reversing thermometers [20] from deep hydrographic casts. These were measured along with salinity from Nansen bottles that closed at depth, capturing a sample of deep water when triggered by a messenger weight slid down the hydro wire. The Nansen bottles inverted, closing valves at the top and bottom and at the same time inverting two special thermometers, one pressure exposed and the other pressure protected in a glass envelope. As the Nansen bottle inverted it also released another messenger weight that slid down the wire to trigger a Nansen bottle clamped to the wire farther down. The reversing thermometers had a necked off region in the capillary tube where the mercury column broke upon inversion capturing the amount of mercury that had been pushed past the necked down portion, somewhat like a fever thermo- meter. The two reversing thermometers were read at a later time when they had both come to room temperature. The amount of mercury in each allowed the temperature at depth to be known and also the pressure known that was responsible for a difference in the two tempera- ture readings. The temperature difference was due to the compression of the glass capillary tube of the exposed thermometer. A precision of 2 millidegrees C was possible from the best qualified reversing thermometers and I had it on the authority of Geoffrey Whitney at WHOI that after a decade of calibrations between cruises, his thermometers could be predicted to read accurately to this standard.

2.2.6 Housings

Housing materials and coatings have been impacted by innovations in metallurgy and plastics as well as bioactive and slippery materials for coatings. The realization that aluminum

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works where steel will not for a Swallow float has been mentioned and the benefits of glass housings, immensely strong in compression and also lightweight and less compressible than water, has been referred to above. But titanium has become a housing material sought after for instruments and deep diving submersibles because it is very strong, relatively lightweight and resistant to corrosion. Plastics such as Delrin, a polyoxymethacrylate, are non-corroding and used for instrument housings to be deployed in shallow depths. These materials are relatively new to oceanographic instrumentation. For very high performance, there have been graphite fiber-wound housings in which the angle of the fibers about 63° to the axis matches the strength of the composite to the stress in the cylinder where the circumferential stress is twice that of axial stress.

2.2.7 Coatings

Coatings have relied mostly on biocide properties such as copper and tributyl tin but recently slippery coatings have been developed and used to provide a non-stick surface to which marine organisms and algae cannot get a grip. These are non-toxic and are not detrimental to the environment. They are also easy to clean. I have started testing a non-fouling coating made for boat propellers called PropSpeed [21]. I am about to start testing one made for geophone streamers called ClearSignal.

2.3 Communications Radio resulting from Marconi’s spark gap transmitters in 1901 and then De Forest’s triode in 1907 had significant impact on shipping. But it was underwater communications that became important in the age of AUVs starting about 1970.

2.3.1 Underwater Acoustics

The ocean is less absorptive and opaque for sound waves than for light; even the clearest water has an attenuation length for light of 50 m. Electromagnetic radiation is similarly attenuated so that only extremely low frequencies can penetrate more than a few hundred meters

beneath the surface. But the attenuation length for sound at low frequencies is sufficiently large that cylindrical spreading becomes the limitation and sound at 220 Hz can be heard above the background noise at ranges of several thousand kilometers. At 56 Hz, a sound source at Heard Island in the southern Indian Ocean was detected at Bermuda in the Atlantic and Big Sur in California, essentially circling the globe [22]. This experiment, pioneered by Walter Munk, led to low-frequency tomographic transmissions between Hawaii and Big Sur until it was curtailed by environmentalists concerned that it was too loud for the Grey Whales migrating along the California coast. Someone had failed to note that the decibel-referenced sound level was not the same as that used in the atmosphere and got the sound level wrong by a factor of 1000, saying it was as loud as a jet plane taking off but the rebuttal was unheard by the public; the damage had been done and could not be undone.

2.3.2 Acoustic Telemetry

John Proakis at Northeastern University had been exploring how communications in underwater acoustic systems could take advantage of the characteristics of the sound channel and avoid the problems of multipath, noise bursts and deep fading. His student Milica Stojanovic and her Postdoctoral advisor Josko Catipovic at WHOI developed Viterbi-coded transmissions of characters with equalization that were efficient. Lee Freitag at WHOI continued these develop- ments for such devices as the Micro Modem [23] that has made acoustic communications between AUVs practicable. Whole sessions at Oceans conferences are devoted to this subject. It is a growth industry. Short ranges permit baud rates of up to 100 kilo baud but even long ranges permit 5 kilo baud.

2.3.3 Optical Telemetry

Recent exploration of optical communications at short ranges have demonstrated very high bandwidths because scattering, the more serious of the optical problems with underwater communications, can actually allow a broad

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angle receiver to get more of the light that might otherwise be lost [24]. The benefit of this technique may be the rapid offloading of data from a bottom-mounted sensor by an ROV lowered to within optical range.

2.4 Data Handling Oceanographic data have become voluminous, particularly with the observatories that send data continuously. Without tools for data handling, these data would choke us and even with the tools the volume of data is of some concern. But data handling has been an issue for the larger community and tools have been invented. Principally among those of great impact is the Fast Fourier Transform (FFT) [25]. Tukey from Princeton University had presented this at a symposium in 1964 and it allowed spectra of signals to be computed without vast resources being tied up on mainframe computers, the only practical way to do such digital analyses prior to 1964.

2.4.1 Matlab Matlab [26] was developed in 1977 and owes some debt to the problems of oceanography because the early examples in the instructions part of the user manual (it was still in the days of manuals) were from Sarah Little’s WHOI PhD work. With the Signal Processing toolbox of Matlab, one can do FFTs with a few lines of code and filter, invert and otherwise process data on a PC without pain. It is almost too easy, allowing us to lose sight of the physical processes we are analyzing.

2.4.2 Internet While the Internet is strictly speaking an innovation in communication, it is in data handling that it has had its greatest impact on oceanography. DARPANET [27] was a development for sharing information in the 1970s and, with the establishment of the personal computer, the Internet allowed advertisers and scientists to gain access to customers and to one another. It permitted large projects to share data sets. And it has now facilitated the establishment of ocean observatories.

2.5 Signal Processing and Digital Signal Processing A related field to data handling and processing, signal processing, actually had its origins in ocean problems, granted they were military rather than scientific. The need to detect submarines and other covert threats demanded that signal processing techniques be developed. Bayesian statistical analyses [28] and other techniques were employed and Signal Processing became a field unto itself. Session tracks at Oceans conferences are devoted to Signal Processing.

The demands of cell phones and other land based signal processing for consumer systems has led to digital signal processing with integrated circuits that perform multiply and add operations at high speed. These have permitted advances in underwater acoustic telemetry to be miniaturized in such devices as the Micro Modem.

2.6 Miniaturization Digital electronics and microprocessors are simply an example of the miniaturization that has enabled low power, compact and immensely complex instruments to be put in the ocean for measurements. The decrease in size of transistor gates has given us flash memory storage and the photoetching techniques developed for integrated circuits have been adapted for chemical and biological Lab-on-Chip type sensors.

3. Oceanographic Instrumentation Some developments that have led to instrumenta- tion have been described but there are oceano- graphic instruments of significance that deserve mention in their own right because, while they could not have come into being without innovations outside oceanography, they have been seminal in advancing our knowledge of the ocean.

3.1 CTD

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Neil Brown, shown in Figure 3, sought an electronic way to take density profiles of the ocean and using the conductivity ratio of an unknown sample of seawater to a standard salinity sample at the same temperature, he had the beginnings of a CTD or Conductivity,

Fig. 3: Neil Brown is confronting his CTD on the research cruise, FAME, the Fine and Microstructure Experiment. The CTD digitally measured conductivity, temperature and pressure (depth) for conversion to salinity and density on the newly-available desktop computers in the ship’s laboratory.

Temperature, Density sensor. The lab salinometer that resulted from his thermostatically-controlled conductivity-ratio instrument was generalized to include temperature corrections so that the salinometer did not need to be thermostatically controlled. Later, the pressure dependency of conductivity was studied and a correction for pressure was determined. Alternatively, this led to a cable-lowered instrument that computed salinity, temperature and pressure for transmission up the cable. This device, the STD [29], was made and sold by Bissett-Berman in 1965 where Brown was then employed. In 1969, Brown came to WHOI where he developed a digital version of the STD with greater precision since it was then possible to do digital computations on a small computer on board a ship and the CTD was the result [30]. The CTD returned 30 samples a second of conductivity, temperature and pressure with a resolution of 1 part in 65,000 (216). This gave a temperature resolution of 0.5 millidegrees C, sufficient to compute salinity to 0.001%. The precision of the measure- ment had to match the resolution and Brown used ratio transformers for his successive approxi- mation A/D converter. His first CTD was built

with small conductivity cells and a fast platinum resistance thermometer to detect micro- structure, a hot topic in 1970. He called the CTD the Microstructure Probe and I built number 3 in the series to study microstructure myself.

3.2 Acoustic Doppler Profiler Current measurements have been a late develop- ment in oceanographic observations, in part because vectors are hard to measure compared to scalars and in part because the ocean is a stratified but turbulent fluid and thus complex to measure. Lagrangian drifters were used to measure the flow of the Gulf Stream as early as 1873. Point measurements of current extend back to 1877 when a current meter was lowered into the Adriatic Sea by Ernest Mayer. A later deployment of an Ekman current meter is shown in Figure 4. But point observations, even when extended for months as was done with moored current meters, such as the Geodyne 850 and its successor VACM, could not capture the full stratified variations in current that exist in the ocean.

Fig. 4: An Ekman Current meter is being deployed in 1922. This instrument indicated speed and direction from a depth to which it was lowered by dropping balls into a compass-aligned cup when the propeller had turned a preset number of revolutions.

Thomas Sanford obtained profiles of current with a dropsonde electromagnetic velocity profiler in FAME and one used in 1973 is shown in Figure 5. He has continued to use the EMVP technique [31]. But, the first moored acoustic

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Doppler profiler was that employed in CODE (Coastal Ocean Dynamics Experiment) in 1991. The Acoustic Doppler Current Profiler (ADCP) [32] built for Jim Irish and Neal Pettigrew of University of New Hampshire by Fran Rowe and Kent Dienes gave rise to an industry, first with RDI and then its spinoff company SonTek and its spinoff company Nortek. Aanderaa got into the acoustic Doppler point current measurement market with their RCM9 and RCM11 Doppler current meters. And, ADCPs, as made by RDI (now Lockheed RDI), are routinely mounted on ship hulls, AUV hulls as shown in Figure 6 and moorings both at the top, looking down and on the bottom, looking up. The technology used in these devices is essentially sonar for the acoustic transmission and detection but also signal processing circuits consisting of multiply and add circuits. These have been adapted by ocean engineers for signal processing and have become powerful instrumentation engines for everything from communications to current measurements.

Fig. 5: The Electro-Magnetic Velocity Profiler (EMVP) of Tom Sanford is shown at the rail ready for dropping overboard where it records the electric field in the seawater due to the motion of the water in the earth’s magnetic field.

Fig. 6: Autosub is equipped with an Acoustic Doppler Current Profiler, ADCP, for measuring the current beneath it and for tracking the motion over the bottom if close enough or from the underside of the

ice, if equipped with an upward-looking ADCP for missions beneath shelf ice in Antarctica.

3.3 Vehicles Submersibles have caught the imagination of ocean explorers and deep-diving research submersibles have benefited from syntactic foam, high strength titanium hulls, acrylic pressure windows and acoustic communications. The DSV Alvin [33] at WHOI has an enviable record of dives not to mention several serious accidents including the one where the pilot and his observers fled the sinking sub as it was being lifted out of the water, leaving their lunches behind. A year later, when Alvin was recovered, the sandwiches, soup and apples were still un- spoiled leading to the field of hyperbaric biology.

3.3.1 Remotely Operated Vehicles

Robert Ballard, a devoted user of Alvin, realized that surveying the sea floor in a manned submersible was too slow for all but the most intricate work and an ROV would make better use of the time of the ship and the scientists. Based on this conclusion, he developed the ROV Jason/Medea [34] in which Medea was a clump weight with cameras that allowed Jason to navigate free from surface-wave heave. This development was done at WHOI and demon- strated its capability by exploring the shipwreck, HMS Titanic. Combination missions can be accomplished with the submersible diving during the day and the ROV being deployed at night. Still, no one is willing to have the ROV deployed at the same time as the manned submersible in case there is trouble.

3.3.2 Autonomous Underwater Vehicles

If the night companion to the submersible Alvin could be an autonomous vehicle, an AUV, the conflict about simultaneous operations disappears so Al Bradley at WHOI designed the Autonom- ous Benthic Explorer, ABE [35], to hover over a hydrothermal vent or to run survey lines photographing the bottom in precisely navigated rows, “mowing the lawn”. Many developments were needed to make this autonomous vehicle

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work, one being battery packs and lowering power demand. But meanwhile a different kind of AUV was being developed for shallow high-speed survey work, REMUS [36] and it caught the eye of the US Navy for mine hunting among other activities. In the UK, Autosub [37] was developed to survey under the Antarctic Ice Shelf among other missions. Control, navigation, communications, sensing and power management have been issues with all of these AUVs.

3.3.3 Gliders

Douglas Webb had a dream. His SOFAR floats had helped reveal large scale ocean turbulence in the MODE and POLYMODE experiments of the 1970s by generating “spaghetti” diagrams of drift tracks over the scale of 500 km in the western North Atlantic Ocean but he envisioned driving the floats to cover much larger regions of the ocean. He observed that a vehicle speed of only one knot would overcome all but the most intense currents and could be supported with less energy than was required to transmit the sounds used to track the drifters. He proposed having such moving floats to Hank Stommel in 1980 and Stommel observed that a glider could be made where propulsion is achieved by changes of buoyancy with a pump rather than by propeller and Webb observed that by using the thermal stratification of the thermocline a heat engine could be constructed that would power itself from the thermal difference. Thus, the glider was invented [38]. It would be two decades before this vision became reality but today there are hundreds of gliders sampling the ocean and returning data by satellite. Fleets of gliders were proposed recently to obtain synoptic observations over tens of kilometers at once, creating an interesting navigation and control problem that was addressed by at least one session at the Oceans 2011 conference in Santander, Spain. The glider is a new technology from which marine science is benefiting.

3.3.4 Hybrid ROV/AUVs Nereus now operating at WHOI is a hybrid vehicle with an ROV carrying the AUV to a

deep location from which the AUV drives out, much as Jason did in the Medea/Jason ROV but Nereus is mechanically untethered. There is a fiber optic link back to the subsurface vehicle from a pair of spool, one on each vehicle, that can lay several kilometers of optical fibers from both ends. This provides the high bandwidth that an ROV has with the freedom that an AUV has. And Nereus is capable of reaching the greatest depths of the Ocean with ceramic spheres for its buoyancy.

3.4 Moored Profilers Extensions of point measurements of properties or current at an instant of time by a lowered sensor have been replaced in many cases by a profile in space with an ADCP. However, the need to get physical samples over an extended duration has required a physical profiler and the moored profiler, in which an instrument package climbs up and down a mooring line, was the solution. McLane Laboratory manu- factures the McLane Moored Profiler (MMP) shown being launched in Figure 7, developed by Ken Doherty at WHOI [39]. Recently, an acoustic current meter has been added to it to get velocity profiles as well as salinity and temperature profiles. The MMP has even been adapted for measurements under Arctic ice as the Ice Tethered Profiler (ITP) (Figure 8), sending data back by an inductive modem to the surface buoy where it is telemetered by satellite to the lab. I was able to provide an acoustic travel-time current meter, MAVS (Modular Acoustic Velocity Sensor) to the ITP and acquired flux measurements under the ice for heat, salt and momentum [40].

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Fig. 7: The McLane Moored Profiler, MMP, climbs up a buoyed mooring line and climbs down to an anchor obtaining CTD and velocity measurements. In this deployment, the MMP has a CTD sensor and an acoustic current meter.

Fig. 8: The Ice Tethered Profiler, ITP, climbs down a mooring line suspended from a buoy frozen into a hole in the Arctic ice to a hanging weight at 800 m depth. The current meter sensor of MAVS is above and in front of the CTD sensor suite at the top of the housing.

3.5 Observatories The next extension is temporal. Long-term moorings using an ADP can give records of current up to a 600 m range. From a moored profiler, records of temperature and salinity can be made over the profile for long duration. Observatories can extend, to a very long or

indefinite length of time, measurements of physical properties of the water, chemical properties, motion of the water and the sediment and biological activity from a fixed location as long as the cable provides power and collects data [41]. An example of an observatory is shown in Figure 9. Cabled observatories are being emplaced off western Canada and will be placed off the northwestern US in 2013. There are also observatories that are moored arrays with satellite delivery of data and solar power for instruments. In addition, gliders and AUVs can be designed to sense a region around the moorings and report the data either from the surface by satellite (gliders) or by docking and offloading data while charging batteries (AUVs). A European observatory on Porcupine Abyssal Plain is also operating.

Fig. 9: The Martha’s Vineyard Coastal Observatory, MVCO, provides power to two offshore nodes and recovers data from sensors on these nodes by fiber-optic cable. A third Nearshore Node was never installed.

3.6 Sensors Development in sensor technology has permitted analyses previously only possible on shipboard to be done autonomously. Chemical analyzers of CO2 with optical detectors of color change in an indicator have been followed by Lab-on-Chip [42] chemical analyzers for iron, manganese, ammonia, nitrate and nitrite. Oxygen can be quickly and accurately measured with polarographic membranes and with optode optical

Albert J. Williams 3rd et al.: Innovative Technology in Oceanography: Past, Present and Future 14

films sensitive to O2 concentration. Some of these developments had their origins in biomedical labs but most were driven by oceanographic need.

3.6.1 Biosensors

A new group of sensors that distinguish organisms is being developed. Reactions between amino acids and substrates and other more complex entities such as RNA permit quite specific detectors to be fabricated [43]. Harmful algal bloom organisms may soon be identifiable automatically. An in situ flow cytometer is under development as a Lab-on-Chip at National Oceanography Center in Southampton, UK by Matt Mowlem’s group. This will allow nanoplankton and picoplankton to be identified and tracked. What these developments will do is permit deployment on observatories of sensors that replace what formerly could only be done by a shipboard lab.

3.7 Satellites Global coverage owes a great deal to satellites and the oceanographic sensors that have been deployed upon them. Ocean color and tempera- ture, sea-surface roughness, altitude and most recently surface salinity are available through satellite observations. Because of the large fraction of the earth that is ocean, oceanography deserves some of the credit for these satellite programs. Continued improvements in sensors and participation by many nations have promised yet better satellite coverage.

4. Future of Oceanography Innovations are generally spontaneous and their applications to marine science are due to need and vision of practitioners. There are, however, inventions that our land-based society has enjoyed but are also innovations that may have utility for oceanography. In the Oceanic Engineering Society of the IEEE there is to be established a new technology committee named Innovative Technology Committee. It is to bring to the attention of the other 19 Technology

Committees, new technology available in society but not yet incorporated in any of the topics covered by them. As examples where new technologies may be found, I have listed six that may have impact as a start for the Innovative Technology Committee. These deserve listing here as well.

4.1 Social Networks Facebook has become ubiquitous among young people as a means for communication. It requires little besides a means of getting on the Internet but there are indications that it offers access to information with unprecedented ease. It can serve as a means of data sharing and has been proposed as a meeting place for professionals to share ideas.

4.1.1 LinkedIn

A more professional social network, LinkedIn has established professional groups, including the OES although how useful it is has not yet been quantified.

4.1.2 Twitter

Twitter is an instant message of limited length, 140 characters. Yet it has been used to warn of tsunami waves and other fast breaking news since it accesses cell phones, which connect to a large fraction of the population. It is worth some consideration if Twitter, LinkedIn and Facebook offer technologies of value to marine science.

4.2 Consumer Electronics Cell phones, digital cameras, video recorders and iPads are examples of consumer electronics that may have impact on marine science. These were not developed for the benefit of oceano- graphy or even for science. They had popular appeal as their reason for being but we can use them for our purposes. For example, the iPad has capability for instruction that is like a DVD instructional video but in a much simpler package. It might be used to replace the now obsolete user instruction manual and thus improve

Albert J. Williams 3rd et al.: Innovative Technology in Oceanography: Past, Present and Future 15

reliability of high-tech underwater instruments that sometimes suffer from excess complexity for the operator.

4.3 Breaking Scientific Discoveries On occasion some discovery outside oceano- graphy may have impact on marine science. It is difficult to guess what breakthrough might be likely and even harder to guess how it might impact our work. But consider what might soon be discovered—the Higgs boson or dark energy in the cosmos for example. Carbon nanotubes are a more likely discovery that might benefit oceanography. Graphene as a new semiconductor substrate may offer advantages that at present we can’t imagine. Certainly breakthroughs in battery chemistry will have value and they are being explored due to the demand from electric vehicles.

4.4 Serendipitous Realizations Many discoveries of value were serendipitous, meaning that the inventor was surprised by it since he was looking for something else. However, the prepared mind recognizes these discoveries and applies them to problems demanding solutions. These are even harder to identify than scientific breakthroughs because they were not even sought.

4.5 Where does one look for them? They are reported in places like:

4.5.1 Best Inventions of the Year

Time Magazine reports their selection of the best inventions of the year annually and most are little more than old inventions polished up somehow but some are new and unexpected.

4.5.2 Popular Science

The magazine, Popular Science, has articles about inventions that sometimes stimulate one to think of applications for marine science. Examples include drone aircraft, invisibility cloaks (optical materials with properties that

make things beneath them appear to not be there) and frictionless suspension systems.

4.6 Cyber Attacks and Cyber Defenses An apparent cyber-attack, the Stuxnet worm, caused Iran to lose its nuclear fuel-enrichment centrifuges. These centrifuges were computer controlled as so many process devices are and a virus of some sort was introduced into the secure computer system at the Iranian nuclear plant that was able to open the system to external manipulation. No one has claimed responsibility but it is assumed that the attack was a joint effort between the US and Israel. The Ocean Observatory Initiative is developing cyber systems that are almost certainly vulnerable to such invasion and attack. This would have negative consequences for marine science. Symantec reports that one third of their Norton Anti-Virus people are working on detection and disablement of this virus [44]. The new technology of cyber-attacks and cyber defenses potentially might have a great effect on marine science of the future since it will be carried out remotely, automatically and done in cyber space.

5. Consequences of Discouraging Innovation

The short list of consequences to oceanographic science of not innovating is that collection of oceanographic data will become too expensive and will be done little or not at all. The loss of oceanographic data will prevent testing of models and they will diverge from accurate predictions and remain stalled in whatever state they were last validated. Failure to innovate with the models will have a similar ill effect and will prevent prediction and will fail to warn us about pending degradation of our environment. From a military viewpoint, any nation that stops innovating in ocean science risks being unpleasantly surprised by developments under- water or on the surface that it cannot detect and cannot protect against. For this reason alone there is little chance that technological innovation in oceanography will be allowed to lapse.

Albert J. Williams 3rd et al.: Innovative Technology in Oceanography: Past, Present and Future 16

But the consequences for society of a techno- logical lapse in innovation in ocean science is especially dire since it will fail to track ocean acidification, global climate change related to CO2 increase, loss of biodiversity and anticipation of super disasters from tsunami inundation, severe cyclones, drought or flooding from El Nino Southern Oscillation cycles (ENSO), harmful algal blooms, exotic introduced species of animals and plants in ballast water of ships, atmospheric contaminants be they fluorocarbons, pesticides, dust, or aerosols of unhealthy composition. These are dangers and society is quick to react to threats of danger. But perhaps the most serious loss is that of knowledge and understanding of how the earth works. It is almost impossible to predict what new technology will become important and innovation happens as much by chance as by planning. But it is even more difficult to predict the consequences of social developments on the earth. Without under- standing how the earth works, the chances of making mistakes are great. Or to put a positive note at the end of this paper, with understanding of how the earth works, it is more likely that we will do the right thing and make the earth a better place for all: better water, freedom from severe drought or catastrophic flooding and food of nutritious quality for all. Possibly we can reduce the stresses that lead to war.

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