Autonomous Monitoring of the Ocean's Carbon System

Ocean Biogeochemical Processes Group LBNL

Autonomous Monitoring. Satellites like SeaWiFS 'see' the surface only when clouds are absent. Ships are able to remain on station for a few days. In spite of the power of such observations, it is nearly impossible to follow the growth and death of phytoplankton (which occurs on a daily basis). The need to ground truth satellite observations coupled with limitations of ship-board sampling abilities dictate the development of autonomously operating vehicles deployed in the oceanic water column. Our interest is to exploit inexpensive vehicles that are capable of profiling the water column twice a day and returning information on carbon system parameters, upper ocean temperature and salinity via a satellite communications link.

The basis for such an approach comes from JGOFS process study results obtained using MULVFS [Bishop, 1999; Bishop et al. 1999] and laboratory studies now in progress at LBNL. Results suggest that such vehicles can be augmented with low power optical sensors for Particulate Organic Carbon (POC) Particulate Inorganic Carbon (PIC).

Carbon Explorer N Pacific Carbon Explorer Positions
Autonomous platform which we will use for carbon system observations. Left. schematic of the Sounding Oceanograph Lagrangian Observer (SOLO). This proven lagrangian profiling float has been widely deployed in the oceans for ocean physics observations. Over 1100 have been deployed to date. The profiler changes its buoyancy by pumping hydraulic oil between reservoirs inside and outside of its pressure case. Middle. Carbon Explorer Prototype with attached WETLabs Inc POC meter. Right. Positions of two Explorers which were deployed in the Subarctic Pacific near Station PAPA (50N 145W) on April 10 2001. Carbon Explorer 1128 (SOLO1128) completed nearly 400 dives by December 24 2001. 10 more Explorers have been deployed since.

References:

Bishop, J.K.B., T.J. Wood, R.E. Davis and J.T. Sherman (2004) Robotic Observations of Enhanced Carbon Biomass and Export at 55S. Science 304, 417-420. [LBNL #53136]

Bishop, J.K.B., R.E. Davis and J. T. Sherman (2002) Robotic Observations of Dust Storm Enhancement of Carbon Biomass in the North Pacific. Science 298, 817-821. [LBNL #50120]

Guay. C.K. and J.K.B. Bishop (2002) A rapid birefringence method for measuring suspended CaCO3 concentrations in water, Deep-Sea Research I, 49, 197-210 [LBNL #46895].

Bishop, J.K.B. (1999) Transmissometer Measurement of POC. Deep-Sea Research I. 46(2) 353-369.

Bishop, J.K.B., S.E. Calvert, and M. Y.-S. Soon (1999). Spatial and Temporal Variability of POC in the Northeast Subarctic Pacific. Deep-Sea Research II. 46(11-12) 2699-2733.

Powerpoint

Brief Highlight Summary of our 2002 and 2004 papers [Size = 3MB]

Funding:

National Oceanographic Partnership Program (NOPP). The 1999 project description may be read here. and its 2001 renewal here.

Related project Project ARGO

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