Southern ocean site descriptions table of Contents

Site : Agulhas Return Current Reference Station

Equatorward of Agulhas Return Current

Short description:

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  1 surface buoy with slackline (reverse catenary) mooring
  
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  Variables measured:
  

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  Surface: wind speed and direction (from a sonic anemometer), air temperature, relative humidity, rain, shortwave and longwave radiation, 1m sea surface temperature and salinity, barometric pressure; air and sea surface pCO₂.
  
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  Subsurface temperature at 25m. Subsurface sensors will increase after first year, pending funding.
  
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  Ocean currents at 15 m
  
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  All physical measurements are recorded at least every 10 minutes. Carbon measurements are every 3 hours.
  

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  Start date of the time series: planned for Oct 2010-11-1
  
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  Service interval: once per year
  

Scientific rationale:

Similar to the Kuroshio Extension Observatory (KEO), the planned Agulhas Return Current (ARC) reference station will be located just equatorward of a western boundary current extension, where heat, carried poleward by the western boundary current is lost to the atmosphere. As such, both are in regions of intense air-sea interactions. The planned ARC station woold contribute to large collaborative process studies and have strong international partners. Funding is initially through NSF to expedited the deployment of ARC to coincide with the NSF-funded Agulhas Current Transport experiment, led by Dr. Beal (RSMAS). Longterm NOAA funding is pending. Shiptime for ARC is being provided through the Agulhas and Somali Current Large Marine Ecosystem (ASCLME) project. For phase 1, the ARC mooring would carry a reduced suite of sensors to monitor air-sea heat, moisture, momentum, and CO₂ fluxes, surface temperature and salinity and near-surface currents. In phase 2, additional subsurface sensors will be included. All surface and subsurface data are telemetered to shore in near-realtime and made available through the project website: http://www.pmel.noaa.gov/ocs/ in a variety of formats including the standard OceanSITES data format.

Groups / P.I.s /labs /countries involved / responsible:

Dr. Meghan Cronin NOAA / PMEL (ARC lead)

Mr. Christian Meinig NOAA / PMEL (ARC Lead Engineer)

Dr. Christopher Sabine NOAA / PMEL (ARC Lead Carbon Scientist)

Status:

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  planned
  
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  time horizon / long-term plans: Long-term
  
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  funding from NSF (for year 1) from NOAA-OCO (pending, continued)
  

Technology:

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  Moored / autonomous sensors
  
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  real-time telemetry: Daily-averaged and spot meteorological, SST and SSS data transmitted via Service Argos. Hourly surface meteorological and subsurface physical data transmitted via Iridium. Carbon has daily transmissions of 3-hour measurements via Iridium.
  
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  SST measurement: self-contained sensor attached to bridle at 1m below surface
  
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  Profile measurements: Sensors will be included after 2010, pending funding. Sensors would be attached to slackline mooring (pressure sensors should be used to remap observations onto nominal depths).
  

Data policy:

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  real-time data: All data are public from primary telemetry system (Service Argos for meteorological, Iridium for subsurface and carbon).
  
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  delayed mode data: High-resolution data will be made public within 6 months of recovery.
  

Data management:

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  Data Assembly Center (DAC): All data will be accessible through www.pmel.noaa.gov/ocs/data_del.html. Carbon data would be available from the Carbon Dioxide Information Analysis Center (CDIAC).
  
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  Satellite data collection system: Likely Iridium for both physical and carbon data)
  
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  Real-time data processing and distribution system: PMEL realtime processing, QA and web distribution.
  
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  Metadata scheme: see website
  
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  Possibilities of evolution to comply with a more general JCOMM GTS scheme: in compliance
  

Societal value / Users / customers:

Agulhas Return Current Reference Station (ARC) users are anticipated to include the research community, weather and climate forecasting communities, and satellite and numerical weather prediction products assessments communities.

Role in the integrated global observing system:

The ARC mooring would serve as an air-sea flux reference site and as an observatory for the Agulhas Return region of the Southern Ocean. This is a data sparse area, and this mooring is expected to provide an invaluable source of data in a very difficult region to sample.

Contact Person:

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  for information about the site or data: Meghan Cronin (Meghan.F.Cronin@noaa.gov)
  
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  for information about the carbon component: Chris Sabine (Chris.Sabine@noaa.gov)
  

Links / Web-sites:

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  for Project information: http://www.pmel.noaa.gov/ocs/arc.html
  
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  for information on carbon system: http://www.pmel.noaa.gov/co2/moorings/
  

Compiled by: Meghan Cronin (June 2010)

Figure 1. The ARC site (black square), shown in relation to the mean net surface heat flux Qnet into the ocean in units W/m², mean sea level (white contours), and the 3000 m isobath (black contours). Sea surface height contours can be interpreted as streamlines of the surface geostrophic flow. Qnet is from the OAFLUX product.