1. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 1 Site Review - February 2010 Michael Schodlok Ice Shelf - Ocean Interaction in the ECCO2 Data Synthesis Michael Schodlok

2. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 2 Site Review - February 2010 Michael Schodlok Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary E. Rignot Antarctic Ice Mass Loss How much of the mass loss is contributed to basal melting? How much of the mass loss to iceberg calving? Do we capture the mass loss in the freshwater fluxes in our model? Preconditioning to ice shelf disintegration ? What is the impact on the global ocean?

3. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 3 Site Review - February 2010 Michael Schodlok Circumpolar Freshwater Fluxes Iceberg calving : 2016 Gt/a => 70 mSv (Jacobs et al. 1992) Ice shelf basal melting (BRIOS): 906 Gt/a => 28 mSv (circumpolar) - Hellmer 2004 Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Modeling without iceshelves: Sea ice thinning, increase of bottom salinity (Hellmer 2004) Implications beyond Antarctic Circumpolar Current (Hellmer et al., 2005 Schodlok et al., 2007)

4. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 4 Site Review - February 2010 Michael Schodlok Model Set up: Ocean model MITgcm z-coordinates (shaved cells) 6 `Faces` à 510x510 ~ 18 km 50 vertical layers ECCO2 data syntheses are obtained by least squares fit to available satellite and in-situ data An objective function expresses the extent of optimization: J = u T Q -1 u + n T R -1 n Estimating the Circulation and Climate of the Ocean, Phase II: High Resolution Global-Ocean and Sea-Ice Data Synthesis http://ecco2.jpl.nasa.gov Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary regional sub-domain

5. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 5 Site Review - February 2010 Michael Schodlok Thickness [m] Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Antarctic Ice Shelves in ECCO2 ICEsat/GLAS: DEM (J. Bamber) BEDMAP: Water Column Thickness -> Firnlayer correction (van den Broeke) => Draft + Water Column Thickness = Cavity Bathymetry Bathymetry: Smith and Sandwell 2008, 1 min, v11.1 Integration Period: 1979 - 2007 OBCS: from optimised Cube78 solution Surface forcing: ERA40-ECMWF blend Amery Data – Ben Galton-Fenzi (UTAS) Amundsen Sea bathymetry – Frank Nitsche (LDEO) WAIS/SGLOBEC – Mike Dinniman (ODU)

6. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 6 Site Review - February 2010 Michael Schodlok Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Strong melting in Amundsen – Bellingshausen Seas Melting in Eastern Weddell Sea Melting and freezing pattern in three major ice shelves 1979 - 2007 Melting dh/dt < 0 Freezing dh/dt > 0 (Joughin & Padman, GRL, 2003)

7. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 7 Site Review - February 2010 Michael Schodlok Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Jacobs et al., 1996;Hellmer, 2004; Thoma, 2005; Smedsrud et al, 2006;Payne et al., 2007 Circumpolar FWF 57 mSv ± 7 mSv 28 mSv (Hellmer 2004) ~55 mSv (E. Rignot) Weddell Sea: 3.51 mSv ECCO2 9.10 mSv (Timmermann, 2001 )

8. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 8 Site Review - February 2010 Michael Schodlok AUV Data (K. Nicholls, BAS) Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Ice shelf Seabed

9. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 9 Site Review - February 2010 Michael Schodlok Weddell Sea Ross Sea WAIS Amery Filchner Ronne ROSS Ross Sea ICESAT/GLAS/INSAR observation estimates (E Rignot) ECCO2 Model estimates [m/a] all ice shelves Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Shackleton/ Moscow

10. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 10 Site Review - February 2010 Michael Schodlok Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Temperature [°C] Depth [m] Temperature [°C] Depth [m]

11. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 11 Site Review - February 2010 Michael Schodlok IceBridge - provides : Pine Island Ice Shelf new bathymetry data Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary

12. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 12 Site Review - February 2010 Michael Schodlok Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary Antarctica vs Greenland Processes at the Ice Front

13. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 13 Site Review - February 2010 Michael Schodlok Dimitris Menemenlis, Yun Xu, Eric Rignot Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary IceBridge - provides : high resolution data for Greenland

14. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 14 Site Review - February 2010 Michael Schodlok Summary and Outlook FWF doubled compared to previous circumpolar estimates similar order of magnitude to satellite derived estimates with large deviations in the WAIS and Shackleton IS areas. vertical Resolution: increase melting in WAIS region, decrease in the eastern Weddell implementation in global ECCO2 model run (cube86 underway) IceBridge data important for modeling freshwater fluxes in Antarctica and Greenland data for Motivation – ECCO2 Model – Freshwater Fluxes – Vertical Resolution - IceBridge – Summary

15. Click to edit the title text format Click to edit the outline text format –Second Outline Level Third Outline Level –Fourth Outline Level »Fifth Outline Level »Sixth Outline Level »Seventh Outline Level »Eighth Outline Level »Ninth Outline Level 15 Site Review - February 2010 Michael Schodlok Publication: Schodlok and Menemenlis: On Ice Shelf Ocean Interaction in the ECCO2 data synthesis: Part I – Model evaluation, in prep. Schodlok and Menemenlis: On Ice Shelf Ocean Interaction in the ECCO2 data synthesis: Part II – Circumpolar freshwater estimates, in prep. Presentation: Schodlok and Menemenlis: Estimating Antarctic Freshwater contribution to the Southern Ocean in the ECCO2 Data Synthesis, 2009, MOCA-09 Joint Assembly, 19-24 July Thanks to D. Menemenlis, A. Khazendar, NPP ORAU