The evolution of ocean temperature measurement systems is presented with a focus on the development and accuracy of two critical devices in use today (expendable bathythermographs and conductivity-temperature-depth instruments used on Argo floats). A detailed discussion of the accuracy of these devices and a projection of the future of ocean temperature measurements are provided. The accuracy of ocean temperature measurements is discussed in detail in the context of ocean heat content, Earth's energy imbalance, and thermosteric sea level rise. Up-to-date estimates are provided for these three important quantities. The total energy imbalance at the top of atmosphere is best assessed by taking an inventory of changes in energy storage. The main storage is in the ocean, the latest values of which are presented. Furthermore, despite differences in measurement methods and analysis techniques, multiple studies show that there has been a multidecadal increase in the heat content of both the upper and deep ocean regions, which reflects the impact of anthropogenic warming. With respect to sea level rise, mutually reinforcing information from tide gauges and radar altimetry shows that presently, sea level is rising at approximately 3 mm yr-1 with contributions from both thermal expansion and mass accumulation from ice melt. The latest data for thermal expansion sea level rise are included here and analyzed. Key Points Oceanographic techniques and analysis have improved over many decadesThese improvements allow more accurate Earth-energy balance estimatesUnderstanding of ocean heat content and sea-level rise has also increased ©2013. American Geophysical Union. All Rights Reserved.

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A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change

A hybrid-driven underwater glider model, hydrodynamics estimation, and an analysis of the motion control

This paper introduces the Autosub Long Range Autonomous Underwater Vehicle being developed at the National Oceanography Centre, Southampton. This propeller driven vehicle is designed to have a 6000m depth rating and a 6000km range. This is achieved by reducing the propulsion power by travelling slowly and hotel power by careful component selection and husbanding of resources. The challenges associated with net buoyancy compensation and low Reynolds number phenomena are outlined, and a passive compensation scheme is described. Early field trials are discussed, and the AUV's role in the upcoming FASTNEt science programme is outlined.

Autosub Long Range: A long range deep diving AUV for ocean monitoring

A review of unmanned vehicles for the detection and monitoring of marine fauna

Pierre Testor(1), Gary Meyers(2), Chari Pattiaratchi(3) , Ralf Bachmayer(4), Dan Hayes(5), Sylvie Pouliquen(6), Loic Petit de la Villeon(6), Thierry Carval(6), Alexandre Ganachaud(7), Lionel Gourdeau(7), Laurent Mortier(8), Herve Claustre(9), Vincent Taillandier(9), Pascale Lherminier(10), Thierry Terre(10), Martin Visbeck(11), Johannes Karstensen(11), Gerd Krahmann(11), Alberto Alvarez(12), Michel Rixen(12), Pierre-Marie Poulain(13), Svein Osterhus(14), Joaquin Tintore(15), Simon Ruiz(15), Bartolomeo Garau(15), David Smeed(16), Gwyn Griffiths(16), Lucas Merckelbach(16), Toby Sherwin(17), Claudia Schmid(18), John A. Barth(19), Oscar Schofield(20), Scott Glenn(20), Josh Kohut(20), Mary Jane Perry(21), Charlie Eriksen(22), Uwe Send(23), Russ Davis(23), Daniel Rudnick(23), Jeff Sherman(23), Clayton Jones(24), Douglas Webb(24), Craig Lee(25), Breck Owens(26)

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Gliders as a Component of Future Observing Systems

Similar in size (62 kg, 18 m long) and shape to the Seaglider [1], the Deepglider is an instrument platform designed to glide to depths of 6000 meters To achieve these depths, a composite pressure hull of thermoset resin and carbon fiber was developed in a two phase design and test approach To take advantage of the substantial engineering effort put into the Seaglider, the Deepglider was designed to use many of the same components and technologies A Deepglider was deployed in November 2006 off the Washington state coast It remained at sea for 39 days, diving to a maximum water depth of 2713 meters, and transiting to its target 220 km offshore, before returning and being recovered near shore The Deepglider, while not yet achieving its design goal of 6000 meters, demonstrated that composites can provide a strength-to-weight ratio exceeding that of metals and can be optimized for hydrodynamic body shapes This paper describes the Deepglider development and the issues of compressibility for a profiling glider

The Deepglider: A Full Ocean Depth Glider for Oceanographic Research

A program to extend the operating depth of Seaglider from 1000 m to 6000 m began in 2002 at the University of Washington. The Deepglider program used carbon fiber composites for the pressure hull because of their ability to achieve weight to displacement ratios of less than 0.5. Advanced fabrication technology, more common in the aerospace industry, allowed the pressure hull to be identical to the shape of the Seaglider AUV so that many of the Seaglider components could be used on Deepglider. In this paper, we describe the development of the carbon fiber/epoxy pressure hull, including material characterization, the design of the interlaminar shear control sleeve, and pressure testing of six pressure vessels. Three of these hulls used a unique tapering diameter, tapering wall thickness construction. A more complete description of the Deepglider program is provided in a companion paper.

Composite Pressure Hulls for Autonomous Underwater Vehicles

A new autonomous, underwater glider is presented that uses core technology from the University of Washington gliders and features a novel buoyancy engine for coastal profiling. This free-swimming, self-contained, 74 kg instrument is a companion to the 1000 m Seaglider and the 6000 m Deepglider, and was developed in partnership with NOAA's Pacific Marine Environmental Laboratory. The Oculus Coastal Glider is specifically designed for shallow water operation $( < 200\mathrm {m})$ to meet NOAA observing requirements in the US Arctic by using a new buoyancy engine based on a hydraulic amplifier. The sensor suite on this initial deployment included conductivity-temperature-depth, photosynthetically active radiation, dissolved oxygen, chlorophyll a fluorescence, colored dissolved organic matter, and backscatter. The Oculus Coastal Glider also has a new modular architecture that allows easy expansion to carry larger and higher power sensors in dedicated hull sections. We present the results of laboratory testing of the buoyancy system, system field testing in a fresh water lake (50 m), Puget Sound (200 m), and an initial science mission in the Bering Sea (70 m).

T.J. Osse

Papers

The Deepglider: A Full Ocean Depth Glider for Oceanographic Research

Composite Pressure Hulls for Autonomous Underwater Vehicles

Oculus Coastal Glider : A New Shallow-water Oceanographic Glider