CoAuthors

Russ Davis (Scripps Institution of Oceanography, United States); John Gilson (Scripps Institution of Oceanography, United States); Kyle Grindley (Scripps Institution of Oceanography, United States); Carol Janzen (Sea-Bird Electronics Inc, United States); Gregory Johnson (NOAA Pacifific Marine Environmental Laboratory, United States); Taiyo Kobayashi (Japan Agency for Marine-Earth Science and Technology, Japan); Nordeen Larson (Sea-Bird Electronics Inc, United States); Serge Le Reste (Institut Francais de Recherche pour l'Exploitation de la mer, France); Guillaume Maze (Institut Francais de Recherche pour l'exploitation de la mer, France); Robert Melvin (Teledyne Webb Research, United States); David Murphy (Sea-Bird Electronics Inc, United States); Ernest Petzrick (Teledyne Webb Research, United States); Stephen Riser (University of Washington, United States); Jeffrey Sherman (Scripps Institution of Oceanography, United States); Toshio Suga (Japan Agency for Marine-Earth Science and Technology, Japan); Philip Sutton (National Institute of Water and Atmospheric Research, New Zealand); Michihiko Tachikawa (Tsurumi Seiki Co Ltd, Japan); Esmee van Wijk (CSIRO Marine and Atmospheric Research, Australia); Matthew Walkington (National Institute of Water and Atmospheric Research, New Zealand); Susan Wijffels (CSIRO Marine and Atmospheric Research, Australia); Nathalie Zilberman (Scripps Institution of Oceanography, United States)

While the Argo Program has implemented systematic observations of the global upper ocean, 0 - 2000 m, extension of Argo sampling to the ocean bottom is needed (i) to close regional and global heat, sea level, and freshwater budgets, (ii) for observing ocean circulation and estimating ocean heat and freshwater transports over the full ocean depth, and (iii) for use in ocean reanalyses and forecast models. Moreover, float and sensor technology advances driven by Deep Argo will benefit many applications. With respect to satellite sea surface height, Deep Argo will measure full-depth steric height, and these in combination with satellite gravity measurements provide a dynamically complete set of observations.

Deep Argo floats have been developed including models that sample to both 4000 and 6000 m. Deployment of 4000 m Deep NINJA floats began in 2012; more than 10 instruments have been deployed in the Southern Ocean for scientific objectives until now. Prototype deployments of the 4000 m Deep ARVOR, and the 6000 m Deep SOLO and Deep APEX have also begun. In addition to floats, a Deep Argo CTD, the SBE-61, has been developed by Sea-Bird Electronics, for use in the deep ocean where the highest accuracy and stability are required. A deep ocean trial is being held in June 2014 aboard New Zealand's RV Tangaroa to test sensor accuracy in the SBE-61. Several SBE-61 CTDs will be integrated with the shipboard SBE-9plus CTD system, and multiple casts carried out on the abyssal plain of the Southwest Pacific Basin, in water depth of about 5600 m. Two Deep SOLO floats will be deployed at the same location, and cycled to the ocean bottom every 3 days for about a year.

Planning is underway for the next phase of scientific deployments of Deep Argo floats. This will include national Argo Programs and multi-national Argo consortia deploying regional pilot arrays. A global design for sampling in Deep Argo, coordinated by the Argo Steering Team and contributing to an integrated Deep Ocean Observing Strategy, will be completed once the capabilities and costs of Deep Argo profiling are known. Here status is summarized of Deep Argo float and sensor development and pilot deployments. Preliminary results will be shown from floats and the June 2014 tests of the SBE-61 CTD. The Argo Steering Team welcomes participation of the OSTST in the design of Deep Argo.