Das GO Projekt wird im Rahmen der NEST-Initiative, Künftiger Wissenschafts- und Technologiebedarf, Rahmenprogramm 6, der Europäischen Union gefördert.
Projektdauer: Februar 2006 – Februar 2009
GO is a cross-disciplinary project, which links standard seismic imaging techniques and physical oceanography. In particular, GO will examine internal waves and their interaction with the continental slope where enhanced mixing water masses is expected; and using the extensive marine geophysical database acquired over the past 4 decades, evaluate longer term changes in the ocean structure. Large scale circulation in the oceans is an important process on the Earth for the redistribution of heat. Water masses of different temperature move past each other separated by relatively thin boundary layers. It is across these boundaries that thermal transfer and mixing must occur to maintain circulation. The processes involved in thermal mixing are poorly understood. It is known that mixing in the open ocean is too low to maintain the large scale circulation patterns and that mixing is enhanced around areas of complex tomography and over continental slopes. Understanding this mixing is important: for global circulation issues, because it affects the density distribution of the different water masses and enhances the overturning circulation, and its influence on climate; and for controlling local biochemistry, nutrients, and the fate of biogenic particles. The key is in the role played by the thermal boundary layers and the ubiquitous internal waves that propagate along them, whose dissipation is critical in quantifying thermal mixing of different water masses. The detailed internal structure of these boundaries and the internal waves is difficult to map with sufficient spatial resolution using standard oceanographic techniques. New research has shown that the multi-channel seismic (MCS) method can be used to image boundaries in the water layer with a horizontal resolution of around 10 m which is over two orders of magnitude better than typical oceanographic data. Geophysical oceanography will therefore create new research opportunities to understand ocean mixing processes.
GO will collect a unique combined dataset with simultaneous and co-located oceanographic and seismic data. In addition we will generate a constrained synthetic dataset from theoretical models of the ocean. These two datasets will then be analysed to assess what physical parameters can be reliably extracted, their resolution, and optimum acquisition, processing, inversion and interpretation strategies.
GEOMAR maintains a leading seismic processing facility as well as Europe’s largest academic pool of ocean bottom seismometers and hydrophones. Particular expertise includes the application of seismic imaging techniques such as pre-stack depth migration, seismic inversion methods, waveform and amplitude analysis, and the analysis of the variation of amplitude and frequency with offset.
It is involved in several project work packages. It participates in the two-ship seismic-oceanographic survey, in close co-operation with the project partners, and is responsible for the OBH-experiment. GEOMAR is leading WP5, where it is responsible for the advanced processing and imaging of the collected seismic data.
- Partner 1 University of Durham (DURHAM), Durham, UK. Verantwortlich: Prof. R. W. Hobbs
- Partner 2 Leibniz-Institut für Meereswissenshaften an der Universität Kiel (GEOMAR), Kiel, Germany. Verantwortlich: Prof. M. Visbeck
- Partner 3 Institute français de recherche pour l'exploitation de la mer (IFREMER), Brest, France. Verantwortlich: L. Geli
- Partner 4 Ente per le Nuove tecnologie, l'Energia e l'Ambiente (ENEA), Rome, Italy. Verantwortlich: Dr. V. Artale
- Partner 5 Fundação da Faculdade de Ciências da Universidade de Lisboa (FFCUL), Lisbon, Portugal. Verantwortlich: Dr. L. M. Matias
- Partner 6 Consejo Superior de Investigaciones Cientificas - Inst. Jaume Almera (CSIC), Madrid, Spain. Verantwortlich: Dr. R. Carbonell
- Partner 7 Universite Bretagne Occidentale (UBO), Unite Mixte de Recherche 6538, Brest, France. Verantwortlich: Dr. J.-Y. Royer
- Partner 8 Proudman Oceanographic Laboratory (POL, NERC), Liverpool, UK. Verantwortlich: Dr. J. Huthnance
Papenberg, C., D. Klaeschen, G. Krahmann, and R. W. Hobbs (2010), Ocean temperature and salinity inverted from combined hydrographic and seismic data, Geophys. Res. Lett., doi:10.1029/2009GL042115
Kormann, J., P. Cobo, B. Biescas, V. Sallarés, C. Papenberg, M. Recuero, and R. Carbonell (2010), Synthetic modelling of acoustical propagation applied to seismic oceanography experiments, Geophys. Res. Lett., 37, L00D90, doi:10.1029/2009GL041763
Geli, L., E. Cosquer, R. W. Hobbs, D. Klaeschen, C. Papenberg, Y. Thomas, C. Menesguen, and B. L. Hua (2009), High resolution seismic imaging of the ocean structure using a small volume airgun source array in the Gulf of Cadiz, Geophys. Res. Lett., 36, L00D09, doi:10.1029/2009GL040820
Hobbs, R. W., D. Klaeschen, V. Sallarès, E. Vsemirnova, and C. Papenberg (2009), Effect of seismic source bandwidth on reflection sections to image water structure, Geophys. Res. Lett., 36, L00D08, doi:10.1029/2009GL040215
Klaeschen, D., R. W. Hobbs, G. Krahmann, C. Papenberg, and E. Vsemirnova (2009), Estimating movement of reflectors in the water column using seismic oceanography, Geophys. Res. Lett., 36, L00D03, doi:10.1029/2009GL038973
Krahmann, G., C. Papenberg, P. Brandt, and M. Vogt (2009), Evaluation of seismic reflector slopes with a Yoyo-CTD, Geophys. Res. Lett., 36, L00D02, doi:10.1029/2009GL038964
Ménesguen, C., B. L. Hua, C. Papenberg, D. Klaeschen, L. Géli, and R. Hobbs (2009), Effect of bandwidth on seismic imaging of rotating stratified turbulence surrounding an anticyclonic eddy from field data and numerical simulations, Geophys. Res. Lett., 36, L00D05, doi:10.1029/2009GL039951
Sallarès, V., B. Biescas, G. Buffett, R. Carbonell, J. J. Dañobeitia, and J. L. Pelegrí (2009), Relative contribution of temperature and salinity to ocean acoustic reflectivity, Geophys. Res. Lett., 36, L00D06, doi:10.1029/2009GL040187
Vsemirnova, E., R. Hobbs, N. Serra, D. Klaeschen, and E. Quentel (2009), Estimating internal wave spectra using constrained models of the dynamic ocean, Geophys. Res. Lett., 36, L00D07, doi:10.1029/2009GL039598