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Characteristic Features of DOC in the Labrador Sea based on Multi-Sensor Measurements

AMOC. Characteristic Features of DOC in the Labrador Sea based on Multi-Sensor Measurements. Xiao-Hai Yan 1 , Young-Heon Jo 1 , Feili Li 1 and Tim Liu 2 June 9, 2010 1 Center for Remote Sensing, University of Delaware

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Characteristic Features of DOC in the Labrador Sea based on Multi-Sensor Measurements

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  1. AMOC Characteristic Features of DOC in the Labrador Sea based on Multi-Sensor Measurements Xiao-Hai Yan1, Young-Heon Jo1, Feili Li1 and Tim Liu2 June 9, 2010 1 Center for Remote Sensing, University of Delaware 2 M/S 300-323, 4800 Oak Grove Dr. Jet Propulsion Laboratory, Pasadena, CA 91109

  2. DOC Studies in LS • Labrador Sea Group (1998)- Labrador Sea Deep Convection Experiment • Marshal and Shott (1998)- Open ocean deep convection: Observations, theory and models • Yashayaev and Loder (2009)-Enhanced production of Labrador Sea Water in 2008 • Vage et al.(2009)- Return of DOC to subpolar NAO in winter 2007-2008 • Lozier (2009)-Overturning assumptions based on NAO Remote Sensing? • Fischer et al. (1999)-DOC using SAR (?) • Hermann et al. (2009)-Monitoring DOC from space (Mediterranean Sea) How Good is RS for DOC observations?

  3. DOC and Subsurface Phenomena Detecting Mediterranean Outflow and Meddies (Yan et al.,JPO, 2006)

  4. Methodology (Yan et al.,JPO, 2006) • Integrated Multi-Sensor Data Analysis • Where

  5. NAUCW: North Atlantic Upper Cold Water 2.5 - 5 °C NABCW: North Atlantic Bottom Cold Water 0 - 2.5 °C

  6. Where is DOC in LS? When does it occur? Can we observe/monitor it? How much does water sink? How much contribution to the AMOC…… Chanut et al., 2008

  7. Relation between DOC and NAO Weak DOC Strong DOC

  8. Vertical structures of DOC from floats measurements Weak and strong DOC events? Yashayaev and Loder (2009)

  9. Strategy to detect DOC events using RS Fisher et al., 1999 Two proxies for detecting DOC LST and SST differences and winds’ direction Steric heights and steric ratios

  10. Brunt-Vaisala (Buoyancy) frequency from a Float How long it takes to reach 1800m depth? Can SSHA contain DOC signals?

  11. Land and Sea Surface Temperature with Winds

  12. Satellite observations for weak and strong DOC events Weak DOC events Strong DOC events SSHA LST and SST Winds

  13. Proxy I for DOC events based on temperature differences D C B A

  14. Temperature comparisons over land and sea Monthly temperature for Jan and Feb Weekly temperature for Jan and Feb Weekly temperature from 2006 to 2008

  15. Steric height and its ratio (Sr) for Proxy II Where, α and β are the thermal and the salt expansion coefficients, respectively.

  16. Proxy II for DOC events based on steric height ratio 4900500 4900537 4900683

  17. 2/15~4/15 2/15~4/15 2/15~4/15 STD SSHA Mean SSHA 2006 2007 2008

  18. Direct evidence for DOC by estimating subsurface temperature(Kang, Jo and Yan,2010)

  19. Simulation for STA

  20. Comparisons between estimated and GODAS measurements

  21. Spatial Empirical Mode Decomposition for SSHA (Jo, Yan, Li and Lee 2010)

  22. Spatial Empirical Mode Decomposition for SST (Jo, Yan, Li and Lee 2010)

  23. Preliminary Conclusion • Difficult to detect precondition of DOC, but possible to monitoring DOC after convection. • Two proxies are useful to monitor changes in water column of DOC and non-DOC sites. • Temperature proxy for DOC shows that low SST requires LST threshold at -3C between Green Land and West of Baffin Sea . Steric height ratio proxy shows ~ 8 times larger for strong DOC than weak DOC. • Subsurface temperature can be estimated from SSHA and provide information for AMOC & DOC analyses. • Caution is required in analyzing with satellite data since there are still other similar signatures. • EEMD can be used to decompose different spatial scales.

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