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Συλλογή και αφομοίωση δεδομενων Glider κατά μήκος διατομής της θάλασσας της Λεβαντίνης. Hayes D.
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Συλλογή και αφομοίωση δεδομενων Glider κατά μήκος διατομής της θάλασσας της Λεβαντίνης. Hayes D.

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10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας …

10ο Πανελλήνιο Συμπόσιο Ωκεανογραφίας & Αλιείας
7-11 Μαΐου 2012, Αθήνα
Μεσόγειος Θάλασσα - Μαύρη Θάλασσα: Ένα ωκεανογραφικό «εργαστήριο»

Published in: Technology, Business

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  • 1. Collecting and Assimilating Glider Transects in the Levantine Sea May-August ‘09 data show Cyprus Eddy D. Hayes1, P. Testor2 , S. Dobricic3, G. Zodiatis11OceanographyCenter, University of Cyprus, Nicosia, Cyprus2LOCEAN-IPSL/CNRS, Universite Pierre et Marie Curie, Paris, France3INGV/CMCC, Bologna, Italy
  • 2. Goal: Accurate description of mean state ----> Improve Forecast Accuracy• Method • Collect high resolution temperature and salinity profiles over long periods in upper 1000 m (gliders) • Implement glider data assimilation (3DVAR) in operational regional model (CYCOFOS)• Results: • Cyprus eddy + Atlantic Water always found (>3/2009 with gliders) • Assimilation run shows difference from the control run• Analysis: • Cyprus Eddy dominates a complex circulation • Work needed to quantify improvement in forecast• Conclusions: • RT glider observations gliders unique: improve ocean forecasts
  • 3. Glider description• Battery-powered, buoyancy- driven• 25-50 cm/s, 16-45o slope• CTD, oxygen, fluorescence, optical backscatter, currents• surface transmit/receive for data and instructions every 5h.• 1000 m dive capability Photo: A. Hannides
  • 4. Seaglider description• Low-drag fairing over hull of compressibility ~= seawater• Lithium batteries, ~6 mo life (4600 km or 650 dives to 1km)• Iridium satellite phone for data, instruction transfer• Controlled with file exchange (commands, waypoints, configuration) Photo: U of Washington
  • 5. Missions Accomplished• Since March 2009, over 1930 dives (3860 profiles)• Most to 1000 m
  • 6. EYE of the Levantine TS properties• Depth-ave velocity, Max 30 cm/s• Anti-cyclonic• Radius ~40km• November 2009 to January 2010• Near Eratosthenes Seamount
  • 7. EYE of the Levantine (12/2009)• Sampling the warm core Cyprus Eddy• Labs: LOCEAN, LOV (fr), OGS (it), ULB (be), UCY-OC (cy)• Gliders: physical and biogeochemical context for shipborne measurements – 6 gliders deployed from Limassol – 2 profiling floats – 4 surface drifters – shipborne measurements by CYBO (Cyprus), TARA (French), Merian (German)
  • 8. EYE of the Levantine (12/2009)• Sampling the warm core Cyprus Eddy• Labs: LOCEAN, LOV (fr), OGS (it), ULB (be), UCY-OC (cy)• Gliders: physical and biogeochemical context for shipborne measurements – 6 gliders deployed from Limassol – 2 profiling floats – 4 surface drifters – shipborne measurements by CYBO (Cyprus), TARA (French), Merian (German)
  • 9. EYE of the Levantine Glider (Atalanta)• 23 Nov-1 Dec 2009• Salinity (top)• Temperature (mid)• Dissolved Oxygen (bot)• Asymmetric: south branch of core more focused
  • 10. EYE of the Levantine Glider Comparisons with MS Merian• 10 stations 4-5 Jan 2010• Dives 170-250 7-31 Jan 2010 • 14-22 Jan 2010• Depth-average currents from glider • Geostrophic Velocity (top) and (1000m) and from ADCP (800m) ADCP (bottom) 0
  • 11. OceanVar Dobricic and Pinardi, 2008• Calculates T and S residuals (model ―background‖ minus observations) at every time step data are present• After POM, calculates ―correction‖ T and S based on residuals in window (1.5d)• Applies corrections at the beginning of the next run (20 time steps). Glider (red) and model (blue) S,T profiles Difference (black) and correction (green) 8 Dec 2009
  • 12. Results• Numerical flow ―hindcast‖ simulation: Nov. 2009-April 2010• Daily update of surface forcing and open boundary conditions• Quantify the value of 1 glider, vs 6 gliders, vs floats+ships+gliders• EYE experiment (so far only 0 and 1 completed) Corrections on S and T at 300 m 8 Dec 2009
  • 13. Results• Numerical flow ―hindcast‖ simulation: Nov. 2009-April 2010• Correction to T at 280 m• Glider positions• DAILY
  • 14. Results• EYE experiment assimilating only one glider‘s T, S profiles• Sea surface elevation map at end of simulation: 19 April 2012 No assimilating Assimilating glider data The difference
  • 15. Discussion• Quantify the value of 1 glider, vs 6 gliders, vs floats+ships+gliders• EYE experiment (so far only 0 and 1 completed—see difference below)• See problem at BC
  • 16. Discussion• Quantify the value of 1 glider, vs 6 gliders, vs floats+ships+gliders• EYE experiment (so far only 0 and 1 completed—see difference below)• See problem at BC
  • 17. Work in ProgressOperational Data Assimilation—TODAY: Glider mission and simulations: 16 December 2011 to present Assimilated in CYCOFOS, compared to control run
  • 18. Work in Progress Operational Data Assimilation—TODAY:Salinity at 360 m for control run (L) and D/A run (R) for this Wednesday Need to quantify the improvement by comparing to independent data E.G.: SST, XBT, SLA+MDT, cruise CTD/ADCP
  • 19. Future Work• New FP7 project, GROOM, has started.• Goal: to design a European Glider Infrastructure.• Heavily based on existing, but integrated and improved.‘ • Recommend payloads, protocols, operation centers, etc. • Support policy AND research • monitoring for parameter ‗X‘ • availability for process study ‗Y Photo: TARA Oceans
  • 20. Conclusions• Gliders improve forecasting skill• Quantifying the improvement is not done yet• Eastern Levantine highly variable and full of mesoscale: need real time data Acknowledgements• Funding: FP7-ECOOP, FP7-GROOM, Cyprus RPF and UCY, TARA/Oceans.• Colleagues: MFS, U of Athens (ALERMO and Skiron providers)• Launch/recovery support: Department of Fisheries and Marine Research Photo: A. Hannides