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Oceanography in 2025: Proceedings of a Workshop
The Research Vessel Problem
J. N. Moum,* Eric D’Asaro,† Mary-Louise Timmermans,‡ Peter Niiler§
The workhorses of the US oceanographic research fleet are the 12 Global, Ocean and Intermediate Class vessels that are presently operated by UNOLS. Of these, six (Melville, Knorr, Oceanus, Endeavor, Wecoma, New Horizon) are well past their projected 30 year service lives, with midlife refits > 10 years ago. Another (Seward Johnson) is 25 years old. The remaining five ships have projected service lives to about 2025. The Navy plans to fund two new Ocean Class vessels, to be launched in the next five plus years. With these two new vessels, the US oceanographic research fleet goes from 12 vessels to seven vessels long before 2025 under present planning guidelines, although five of these seven will be past the ends of their service lives by then.
At the same time, the oceanographic community has incurred new obligations in assuming responsibilities for global, regional and coastal observing systems. These include moored, autonomous and drifting assets. While these are commonly billed as replacements for shipboard observations (notwithstanding the need for ships for servicing), their much smaller payload and power capabilities will mean that ships will almost always be capable of more sophisticated, difficult and novel measurements. Ships can go faster than autonomous platforms, can carry
*
College of Oceanic and Atmospheric Sciences, Oregon State University
†
Applied Physics Laboratory, University of Washington
‡
Woods Hole Oceanographic Institution
§
Scripps Institution of Oceanography, University of California, San Diego
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Oceanography in 2025: Proceedings of a Workshop
heavier packages and support a wider range of simultaneous measurements. New sensors and methods, even those destined for autonomous platforms, will inevitably be tested on ships. New autonomous platforms will be tended by ships before being set off on their own. Novel sensors on autonomous platforms will need to be calibrated and verified by more traditional measurements made on ships. Hydrographic programs that catch the water from surface to seafloor must continue and become more complex with the addition of many more biochemical compounds and molecules to be sampled—these require ships. The Southern Ocean is beyond the reach of autonomous probes, necessitating shipboard monitoring.
By 2025, we envision that ships will continue to be a vital part of oceanography, but that their role will have shifted. They will still do the heavy lifting of deploying moorings, servicing long-term arrays and making intensive short-term surveys or hydrographic lines using large, heavily instrumented packages. They will deploy, recover and tend mobile autonomous platforms, although some of this work may be better accomplished from smaller, faster vessels than we have today. Most importantly, we expect that intensive research programs aimed at new understanding of ocean processes will be conducted by a mix of ships (including necessary multi-ship experiments) and other platforms. Intensive ship surveys measuring, for example, a full suite of biogeochemical properties for ecosystem studies, or high-resolution 3D towed and acoustic surveys of ocean density and microstructure for mixing studies, will be supplemented by autonomous platforms placing these intensive ship measurements in a larger space and time context.
For example, the most important problem in physical oceanography today is a resolution of the subgrid scales of ocean circulation models. These scales occupy a broad range in time and space and have great geographical variability. We know that present parameterizations of the physics at these scales are incorrect to varying degrees and that this leads to unknown and unpredictable uncertainties in projections of future global climates, a matter of significance as our planet undergoes large and rapid climate change. Because of the complexity of the processes at subgrid scales, they are not simply studied by routine observation. Rather they require fixed, focused and intensive observations from mobile platforms. To observe such flows requires real time analysis of incoming data from multiple sensing devices by scientists at sea, supplemented by measurements on fixed and autonomous platforms.
In a 1997 article in Oceanus RADM Pittenger, former Oceanographer of the Navy, summarizes the 15-year modernization of the fleet to 1997 that included AGORs 23-25 and several midlife refits, and states, “There is a very important lesson here … replacement of ships is a decadal process.
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Oceanography in 2025: Proceedings of a Workshop
Given a nominal life of about 30 years, planning for ship replacement must begin before the ships to be replaced are 20 years old.”
The addition of the Navy’s two new Ocean Class Vessels is welcome and important, but these are not enough. Oceanographers are in danger of not being able to respond to the challenges of the 21st century. Not yet, but soon.
