Calculation of the MOC Time Series, Data Products and Availability Paul Wright National Oceanography Centre, Southampton (based on work by Stuart Cunningham, Torsten Kanzow, Harry Bryden, Darren Rayner, Julie Collins, David Smeed, Lucas Merkelbach and Joel Hirschi)
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Calculation of the MOC Time Series, Data Products and Availability Paul Wright National Oceanography Centre, Southampton (based on work by Stuart Cunningham,
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Calculation of the MOC Time Series, Data Products and Availability
Paul WrightNational Oceanography Centre, Southampton
(based on work by Stuart Cunningham, Torsten Kanzow, Harry Bryden, Darren Rayner, Julie Collins, David Smeed, Lucas Merkelbach and
Joel Hirschi)
Outline
• How the observed MOC is calculated
• Data Availibilty
• Glider deployment on the Eastern Boundary
The Components of the MOC
The RAPID-MOC Mooring Array
Gridding and Merging the MicroCAT data
The moored MicroCAT data for each section of the Atlantic are merged together to produce profiles of and S.
This is carried out by interpolation and based on pressure as the moorings bend to a degree due to the currents.
The upper section of the eastern boundary 2007/2008, merging the moorings EBH4, EBH3, EBM1 and EBM6. Two other moorings were not recovered.
EBM1
EBH4
EBM6
EBH3
The Internal Mid-Ocean Transports
• The merged and gridded and S profiles are interpolated to form a continuous series.
• Geostrophic transport profiles are then calculated using the dynamic height relationship:
multiplied by the width of each ‘slice’ of the ocean.
• These baroclinic transports are referenced to zero at 4820 dbar.
Modelling the North-Atlantic
western basin
eastern deep basin
eastern/crossMAR basin
T(z) = T(z) west + T(z) east + T(z)crossMAR
Adding the AABW,Ekman, Florida Straits and Western Boundary Wedge Transports
• The mean observed AABW transport is added to the bottom section of the profiles, extending the depth to 6000m.
• The Ekman transports are calculated from the QuikSCAT gridded wind stress dataset produced by IFREMER/CERSAT, they are averaged over the top 100m of the ocean.
• The Florida Straits transports are obtained from underwater cable measurements and can be found at www.aoml.noaa.gov.
• The Western Boundary Wedge transports, between the island of Abaco and WB2 and/or WB3 are measured by current meters and the dataset is produced by Bill Johns at the University of Miami.
The north and southwards transports are observed to balance for periods greater than 10 days. This mass compensation due to barotropic external transports can be observed in the bottom pressure anomaly records.
An approximation based on this is applied to the transport profiles using a hypsometric compensation.
• Lucas Merklebach has worked on comparing the glider data from Bellamite to the mooring EBH4. For this he sampled the glider and S data where the glider is in the region of the mooring and at the same depth as the MicroCATs, averaging across depth profiles where necessary to coincide as close as possible to the MicroCATs reading.
• Comparison of the corrected gridded glider (based on the above) and eastern boundary mooring profiles is ongoing.