Main tasks within ice2sea: Participation in W2, W3, and W4, coordination of work package W4

Description of Institution: The Alfred Wegener Institute (AWI) conducts research in the Arctic, the Antarctic and at temperate latitudes. It coordinates polar research in Germany and provides both the necessary equipment and the essential logistic back up for polar expeditions. Recent additional research themes include North Sea Research, contributions to Marine Biological Monitoring, Marine Pollution Research, investigation of naturally occurring marine substances and technical marine developments. AWI was established as a public foundation in 1980. As a member of the Helmholtz Association of German Research Centres the Foundation Alfred Wegener Institute for Polar and Marine Research includes the Alfred Wegener Institute in Bremerhaven, the Potsdam Research Unit, the Biologische Anstalt Helgoland and the Wadden Sea Station Sylt. The German Federal Ministry of Education and Research (BMBF) covers 90% of financing, the state of Bremen 8%, and the states of Brandenburg and Schleswig-Holstein provide 1% each. In 2007 the foundation had 784 employees and a total budget of 100 million Euros. AWI’s research mission is to improve our understanding of ocean-ice-atmosphere interactions, the animal and plant kingdoms of the Arctic and Antarctic, and the evolution of the polar continents and seas. Given the major role played by these regions within the Earth’s climate system, global change is a central focus of the research effort at AWI.

Department name:  Not applicable

Staff member:  Dr. Hartmut H. Hellmer (HHH)

Profile of staff member: HHH has worked as physical oceanographer since 1984, spent 6 years at the Lamont-Doherty Earth Observatory of Columbia University, New York, starting with a Postdoctoral Research Fellowship, and is now a Principal Investigator at AWI, where he leads the research project in Southern Ocean numerical modeling since 1996. This research activity resulted in the development of the BRIOS (Bremerhaven Regional Ice Ocean Simulations) model, the only circumpolar coupled sea ice-ocean model which includes Antarctica’s major ice shelf caverns and, thus, considers the interaction between ocean and ice shelf base. HHH participated in several Antarctic field experiments, including, as chief scientist, the 1992 US-Russian ice flow drift experiment in the western Weddell Sea (ISW-1) and two Brazilian cruises to the northwestern Weddell Sea as part of the international DOVETAIL project. His research focuses on the role of the Southern Ocean in the global thermohaline circulation, and its response to climate change, but also covers issues in ocean-ice shelf interaction and iceberg life cycles.  He was co-chair of iAnZone, a SCOR (Scientific Committee on Ocean Research) affiliated programme and member of the Autosub Under Ice (AUI) Scientific Steering Committee, U.K. HHH has supervised several master and PhD students at AWI as well as postdoctoral students, financed through his grants from the German Research Foundation (DFG).

Selected references:

Hellmer, H. H., D. Olbers (1989). A two-dimensional model for the thermohaline circulation under an ice shelf, Antarctic Science, 1(4), 325-336.

Jacobs, S. S., H. H. Hellmer, C. S. M. Doake, A. Jenkins, R. Frolich (1992). Melting of ice shelves and the mass balance of Antarctica, J. Glaciol., 38(130), 375-387.

Hellmer, H. H., S. S. Jacobs, A. Jenkins (1998). Oceanic erosion of a floating Antarctic glacier in the Amundsen Sea, Ocean, Ice, and Atmosphere: Interactions at the Antarctic continental margin (S Jacobs, R Weiss, eds ) Antarctic Research Series, AGU, Washington DC, USA, 75, 319-339.

Hellmer, H. H. (2004). Impact of Antarctic ice shelf melting on sea ice and deep ocean properties, Geophys. Res. Lett., 31(10), L10307, doi:10.1029/2004GL019506.

Schodlok, M. P., H. H. Hellmer, G. Rohardt, F. Fahrbach (2006). Weddell sea-iceberg drift: 5 years of observations, J. Geophys. Res. (Oceans), 111(C6), C06018, doi:10.1029/2004JC002661.

Hellmer, H. H., G. S. Dieckmann, C. Haas, M. Schröder (2006). Sea ice feedbacks observed in western Weddell Sea, EOS, Transactions, American Geophysical Union, 87(18), 173, 179.

Rodehacke, C. B., H. H. Hellmer, A. Beckmann, W. Roether (2007). Formation and spreading of Antarctic deep and bottom waters inferred from a chlorofluorocarbon (CFC) simulation, J. Geophys. Res. (Oceans), 112, C09001, doi:10.1029/2006JC003884 .

Hellmer, H. H., C. Haas, M. Schröder, G. S. Dieckmann, M., Spindler (2008).The ISPOL drift experiment, Deep Sea Research II, in press.

Other staff members:  Dr. Klaus Grosfeld (KG),  Dr. Ralph Timmermann (RT), Dr. Frank Wilhelms (FW), Dr. Jens Schröter (JS),  (Alfred-Wegener-Institut, Bremerhaven, Germany)

Profile of staff member:  KG has worked as geophysicist since 1987, starting with a Postdoctoral position at AWI, followed by contracts with partly own projects at different German Universities. He is now a Senior Scientist at AWI, where he is working in the paleo climate dynamics department and coordinator of the Earth System Science Research School (ESSReS). His research activities started from field studies on ice shelf – ocean interaction processes (hot water drilling) and ice-shelf modelling. He developed a high resolution 3d sub-ice shelf – ocean model which has been applied to several ice shelf regions. His research focuses extended on the application of global atmosphere and ocean models for paleo climate applications. He is now in charge of the incorporation of ice sheets into an earth system model at AWI. KG has supervised several master and PhD students as well as postdoctoral students, partly financed through his grants from the Federal Ministry of Education and Research (bmbf) or the German Research Foundation (DFG).

Selected references:

Grosfeld, K., Gerdes, R., Determann, J.(1997). Thermohaline circulation and interaction between ice shelf cavities and the adjacent open ocean. Journal of Geophysical Research, 102/C7, 15595-15610.

Grosfeld, K., Hellmer, H. H., Jonas, M., Sandhäger, H., Schulte, M., Vaughan, D. G. (1998). Marine ice beneath Filchner Ice Shelf Evidence from a multi-disciplinary approach, Ocean, ice and atmosphere Interactions at the Antarctic continental margin (S Jacobs, R Weiss, eds ) Antarct Res Ser , AGU, Washington DC,75,319-339.

Grosfeld, K., Schröder, M., Fahrbach, E., Gerdes, R., Mackensen, A.(2001). How iceberg calving and grounding change the circulation and hydrography in the Filchner Ice Shelf-Ocean System, Journal of Geophysical Research, 106, C5, 9039-9055, doi:2000JC000601 .

Grosfeld, K., Sandhäger, H.(2004).The evolution of a coupled ice shelf-ocean system under different climate states, Global and planetary change, 42, 107-132., doi:10.1016/j.gloplacha.2003.11.004 .

Lange, M. A., Blindow, N., Breuer, B., Grosfeld, K., Kleiner, T., Mohrholz, C.-O., Nicolaus, M., Oelke, C., Sandhäger, H., Thoma, M.(2005). Numerical model studies of Antarctic ice sheet – ice shelf – ocean systems and ice caps, Annals of Glaciology, 41, 111-120.

Thoma, M., Grosfeld, K., Lange, M. A.(2006). The impact of the Eastern Weddell Ice Shelves on water masses in the eastern Weddell Sea, Journal of Geophysical Research-oceans. 111, C12010, doi:10.1029/2005JC003212.

Profile of staff member: RT has worked as an ice-ocean modeller since 1997, spent 2 years with a Postdoctoral Research Fellowship at Université Catholique de Louvain (UCL), Louvain-la-Neuve, Belgium,  and is now a Research Scientist at AWI, where he contributes to the development and application of two families of coupled ice-ocean models. He developed the ice and coupling modules of the BRIOS (Bremerhaven Regional Ice Ocean Simulations) model, unified the treatment of sea ice and ice shelves, and conducted comprehensive studies of the variability of sea-ice formation and sub-ice shelf circulation. He is now responsible for the development and application of the Finite Element Sea ice-Ocean Model (FESOM), which in the past years has evolved into a state-of-the-art research tool. His research focuses on ice-ocean-ecosystem interaction and water mass modification in the Southern Ocean. He took part in three research cruises into the Southern Ocean and has supervised several PhD students at UCL and AWI.

Selected references:

Assmann, K.M., and R. Timmermann (2005): Variability of dense water formation in the Ross Sea. Ocean Dynamics, 55(2), 68-87, DOI: 10.1007/s10236-004-0106-7.

Timmermann, R., H. Goosse, G. Madec, T. Fichefet, C. Ethe, and V. Dulière (2005): On the representation of high latitude processes in the ORCA-LIM global coupled sea ice-ocean model. Ocean Modelling, 8(1-2), 175-201, doi:10.1016/j.ocemod.2003.12.009.

Lefebvre W., H. Goosse, R. Timmermann and T. Fichefet (2004): Influence of the Southern Annular Mode on the sea ice–ocean system, J. Geophys. Res., 109, C09005, doi:10.1029/2004JC002403.

Timmermann, R., A. Worby, H. Goosse, and T. Fichefet (2004): Utilizing the ASPeCt sea ice thickness dataset to evaluate a global coupled sea ice–ocean model. Journal of Geophysical Research, 109, C07017, doi:10.1029/2003JC002242.

Hense I., R. Timmermann, A. Beckmann, and U.V. Bathmann (2003): Regional ecosystem dynamics in the ACC: Simulations with a three-dimensional ocean-plankton model.  Journal of Marine Systems, 42, 31-51.

Timmermann, R., A. Beckmann, and H.H. Hellmer (2002a): Simulation of ice-ocean dynamics in the Weddell Sea. Part I: Model configuration and validation. Journal of Geophysical Researh, 107(C3), 10.1029/2000JC000741.

Timmermann, R., H.H. Hellmer, and A. Beckmann (2002b): Simulation of ice-ocean dynamics in the Weddell Sea. Part II: Interannual variability 1985 — 1993. Journal of Geophysical Researh, 107(C3), 10.1029/2000JC000742.

Timmermann, R., A. Beckmann, and H. H. Hellmer (2001): The role of sea ice in the fresh water budget of the Weddell Sea. Annals of Glaciology, 33, 419-424.

Timmermann, R., P. Lemke, and Ch. Kottmeier (1999): Formation and Maintenance of a Polynya in the Weddell Sea, Journal of Physical Oceanography, 29(6), 1251-1264.

Profile of staff member: FW has worked as a glaciologist since 1994. Since 2005, he is head of the New Technologies section “ice core drilling” and designated speaker of the work package “Role of Ice Sheets in the Earth System” within the up-coming Helmholtz research program “Polar Regions and Coasts in the changing Earth System (PACES)”. FW participated in AWI’s North Greenland Traverse (NGT) 1993–1995 and developed a dielectric profiling tool for fast and non-destructive accumulation studies already in the field. He further applied this tool during the pre-site survey for the European Project for Ice Coring in Antarctica (EPICA) Dronning Maud Land (EDML) deep ice core, where he also collected shallow ground penetrating radar profiles. He received grants from the German science foundation (DFG) in the field of linking dielectric properties of ice cores to synthetic radar traces and supervised MSc and PhD students. Since 2000, FW acted as chief driller for the drilling operation of the EDML ice core and was involved in the field operations and paleo-climatic studies on the EPICA cores and the North Greenland Ice Core Project (NGRIP) core. He is now member for drilling technology in the steering committee of the International Partnerships in Ice Core sciences (IPICS) and the coordinator of the proposal “European Polar Ice Core Treasury Unit and Recovery Equipment (EuropeanPICTURE)” to the European Strategy Forum for Research Infrastructure (ESFRI).

Selected references:

Wilhelms, F., Kipfstuhl, J., Miller, H., Heinloth, K., Firestone, J. (1998). Precise dielectric profiling of ice cores: A new device with improved guarding and its theory, Journal of Glaciology, 44/146, 171-174.

Fischer, H., Werner, M., Wagenbach, D., Schwager, M., Thorsteinnson, T., Wilhelms, F., Kipfstuhl, J., Sommer, S. (1998). Little ice age clearly recorded in northern Greenland ice cores, Geophysical Research Letters ,25/10,1749-1752.

Drücker, C., Wilhelms, F., Oerter, H., Frenzel, A., Gernandt, H., Miller, H. (2002). Design, transport, construction, and operation of the summer base Kohnen for ice-core drilling in Dronning Maud Land, Antarctica., Memoirs of National Institute of Polar Research, Special Issue; 56, 302-312.

Eisen, O., Wilhelms, F., Nixdorf, U., Miller, H. (2003). Revealing the nature of radar reflections in ice: DEP-based FDTD forward modeling, Geophysical Research Letters, Vol. 30, No. 5, 1218. doi: 10.1029/2002GL016403

EPICA, community members (2004). Eight glacial cycles from an Antarctic ice core, Nature, 429, 623-628., doi:10.1038/nature02599.

North Greenland Ice-Core Project members, (2004). High-resolution record of the Northern Hemisphere climate extending into the last interglacial period, Nature, 431, 147-151.

Wilhelms, F. (2005). Explaining the dielectric properties of firn as a density-and-conductivity mixed permittivity (DECOMP), Geophysical research letters, 32, L16501, doi:10.1029/2005GL022808.

EPICA, community members, (2006). One-to-one coupling of glacial climate variability in Greenland and Antarctica, Nature, 444, 195-198., doi:10.1038/nature05301.

Eisen, O., Hamann, I., Kipfstuhl, S., Steinhage, D., Wilhelms, F. (2007). Direct evidence for radar reflector originating from changes in crystal-orientation fabric, The Cryosphere, 1, 1–10, 2007.

Other staff member:  Dr. Jens Schröter has worked at Alfred Wegener Institute for Polar and Marine Research, Bremerhaven since 1987, and for three periods, as a Visiting scientist, University of Tasmania and CSIRO.  Prior to that he wasat the Max-Planck-Institut für Meteorologie, Hamburg.  He is now, department head for Ocean Dynamics, and has wide interests in ocean modelling.

Selected References:

Wenzel, M., Schröter, J.(2007). The global ocean mass budget in 1993–2003 estimated from sea level change, J.  Phys. Oceanogr.  37(2), 203-213., doi:10.1175/JPO3007.1.

Sobolev., et al., (2007) Tsunami early warning using GPS-Shield arrays, J. Geophys. Res., (112), B08415, doi:10.1029/2006JB004640

Hellmer, H., et al., (2005), On the influence of adequate Weddell Sea characteristics in a large-scale global ocean circulation model, Ocean dynamics, 55(2), 88-99. DOI: 10.1007/s10236-005-0112-4

Schröter, J. (2003) Assimilierung von Messdaten, Ozean, Promet, 29, 1-4,55–62.

Schröter, J. et al. (2002) Impact of the Gravity Field and Steady-State Ocean Circulation Explorer  mission on ocean circulation estimates 2. Volume and heat transports across hydrographic sections of unequally spaced stations., J. Geophys. Res. 107 (C2), 4-1–4-20.