Presentation on theme: "SUSTAINED OCEAN OBSERVATIONS FROM MERCHANT MARINE VESSELS A proposal As you know, the Merchant Marine has a presence on the high seas second to none. Analogous."— Presentation transcript:
SUSTAINED OCEAN OBSERVATIONS FROM MERCHANT MARINE VESSELS A proposal As you know, the Merchant Marine has a presence on the high seas second to none. Analogous to satellites with instrumentation for monitoring the atmosphere and ocean surface, these vessels could serve as orbiting platforms for monitoring the interior of the ocean. While we do so to a limited extent today, with instrumentation and data management techniques designed and optimized for these platforms we could open up an entirely new dimension to ocean observation. The following material was presented to the US NSF last year. They suggested we contact SCOR who in turn liked the idea very much, but felt it would be wise to get JCOMMs view and input first, hence this presentation.
This figure shows routes engaged at some level of XBT sampling (todays VOS work). But suppose these vessels could measure currents, obtain temperature and salinity profiles, measure biomass, monitor water quality and optical properties continuously along their routes automatically with no observer onboard. Here are a few examples of whats possible today.
The Nuka Arctica operates on a 3-week schedule between Greenland and Denmark. The ship has a draft of 8 m and in- situ biomass is so rich that the ADCP gets good returns to 400 m. Operated by the University of Bergen. The ship is equipped with TSG, XBT and total CO 2 systems. DMI also releases balloons from a container.
A typical crossing from Cape Farewell to Denmark. Very substantial eddy activity. Single or sparse sections like this tell us nothing about the mean circulation and its change over time. P. Jaccard, UiB
But using 33 sections Øyvind Knutsen (UiB) has resolved the flows around the Reykjanes Ridge in great detail. Note the double flow north, a fine-structure feature in the mean field which sparse sampling and/or low- resolution techniques cant capture. Narrow pipelines indeed, very likely a consequence of the ridge topography.
The 150kHz ADCP-equipped Oleander measures upper ocean currents to ~250m in GS. The 75kHz system reaches to ~600m. The Oleander: 1992 to present
Example of a good weather (no bubbles) ADCP section. The data are uploaded by wireless internet when the vessel docks in Port Elisabeth. We are striving to serve the final product within a few days.
When viewed this way the GS appears to be quite stiff. It can be shown that the exponentials reflect uniform potential vorticity with a jump at the velocity maximum. THE GULF STREAM IN NATURAL COORDINATES The dots in the figure include all time scales, tidal, inertial, meandering, seasonal and interannual. The Oleander program is particularly interested in long- term trends:
The red lines highlight the GS, Slope and Sargasso Sea transports over the 11 years. Integration of velocities across the ship track gives transport in the Slope Sea, Gulf Stream and Sargasso Seas as a function of time. These figures show that we could measure transports across whole oceans at many latitudes.
Mean along and onshore currents in the Slope Sea (after removal of WCRs) based on 282 ADCP sections. These both seasonal and interannual variations superimposed as mentioned earlier. Note the small yet clearly identifiable mean velocities, with fine structure in both the vertical and horizontal. 0.4 Sv 2.5 Sv Flagg et al.
Igor Belkin This figure showing probability of finding a front at the surface is a stark reminder of the richness of fine-structure in the ocean. The radius of deformation is only O(5-40) km. This is the scale we need to resolve in order to understand the dynamics of the ocean.
The above activities have depended very heavily upon on individual efforts to adapt existing instrumentation to the industrial environment of the Merchant Marine. This is fine, but What we really need is instrumentation that operates without the need for any human presence, to operate automatically just as with satellite instrumentation. I have no doubt that as we come to recognize what the Merchant Marine can do for ocean observation, we will start to dream about other variables to add to the measurement suite. Here are a few examples:
The ADCP is a well- established technology. No reason why it cant reach deeper working at lower frequencies.
The acoustic correlation current profiler (ACCP) towed behind the vessel is possible.
Tracking a precisely timed acoustic BT using a small baseline set of hydrophones mounted on the bottom of the ship.
Acoustic thermometry from the surface using fish and other nekton as scatterers.
Brooke Ocean Moving Vessel Profiler CTD, Chl, light, small volume water sampling Their top model can profile to 800 m at 12 Kts. A technician would be required, but whole system could reside in a container.
A common thread through the entire discussion is repeat sampling in the horizontal - the most inaccessible and costly dimension in Oceanography. This explains why Satellite Oceanography has been so phenomenally successful - besides its temporal and spatial coverage also its high horizontal resolution. But the piecemeal way we work with the Merchant Marine today makes it all but impossible to develop a systems approach to the study of the subsurface ocean. We need to develop a new approach or paradigm for working with the Merchant Marine. It seems to me we should think in terms of a deliberate partnership - something along the following lines:
Merchant Marine Industry Prepare vessels at construction time for future programs Identify routes, works closely with OSC to maintain continuity Ocean Observing Community Helps develop new science In charge of data flow, processing, distribution, analysis, assimilation Trains future scientists and engineers Instrumentation Industry Define, develop, and certify new instrument concepts Understand vessels for optimal instrument performance and reliability Ocean Space Center(s) Leads the development of cutting- edge science and engineering for ocean space observing systems Perhaps modeled after an ESA or NASA
Merchant Marine Industry Prepare vessels at construction time for future programs Identify routes, works closely with ISC to maintain continuity Ocean Observing Community Helps develop new science In charge of data flow, processing, distribution, analysis, assimilation Trains future scientists and engineers Instrumentation Industry Define, develop, and certify new instrument concepts Understand vessels for optimal instrument performance and reliability Ocean Space Center(s) Leads the development of cutting- edge science and engineering for inner space observing systems Since meeting with NSF last year my thinking has converged towards something like this diagram. It is ambitious for sure, but this may be what we need in order to break out of our incremental approach to ocean observation and working with the Merchant Marine?! Perhaps modeled after an ESA or NASA
Your reactions, thoughts and suggestions on the above would be much appreciated. Thank you!
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