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Earth rotation and the ocean's circulation

The goal of this project is to contribute to the interpretation of Earth rotation measurements with a focus on the role of the ocean. The oceanic angular momentum for the last fifty years will be estimated as accurate as possible, where two complementary methods will be applied. The first is advanced numerical ocean modelling which considers all relevant processes and which will be extended to derive the local torques excited by the ocean on the solid Earth and vice versa. The second approach tries to close the angular momentum budget by assimilation of angular momentum time series into a global circulation model. To this end the measured Earth rotation parameters are corrected for best estimates of the contributions by the atmosphere, the cryosphere, and hydrology. This 'measured' ocean angular momentum time series is subsequently assimilated into a global ocean model to determine Earth rotation parameters that are consistent with observations and ocean dynamics. The result will also be a major step forward in determining which part of the observed sea level rise is due to global warming in contrast to an increase in ocean mass.


Involved institutions:

Scientists / Staff:

  • Dr. Jens Schröter, Alfred-Wegener-Institut für Polar- und Meeresforschung AWI,
    Tel.: +49 471 4831 1762, Fax +49 471 4831-1797, E-Mail: jschroeter (at) awi-bremerhaven.de
  • Prof. Dr. Maik Thomas, GeoForschungsZentrum Potsdam GFZ,
    Tel.: +49 331 288 1147, E-Mail: mthomas (at) gfz-potsdam.de
  • Andre Grötzsch, GeoForschungsZentrum Potsdam GFZ,
    Tel.: +49 331 288 1770, E-Mail: groetzsch (at) gfz-potsdam.de
  • Jan Saynisch, GeoForschungsZentrum Potsdam GFZ,
    E-Mail: saynisch (at) gfz-potsdam.de

Publications:

  • Saynisch J.; Thomas, M.: Ensemble Kalman-Filtering of Earth rotation observations with a global ocean model. Journal of Geodynamics, GEOD1089, doi:10.1016/j.jog.2011.10.003, 2011.
  • Saynisch, J., Wenzel, M., and Schröter, J.: Assimilation of Earth rotation parameters into a global ocean model: excitation of polar motion. Nonlin. Processes Geophys., 18, 581-585, DOI:10.5194/npg-18-581-201, 2011. Abstract
  • Dill, R., Dobslaw, R.: Short-term Polar Motion Forecasts from Earth System Modeling Data. Journal of Geodesy, 84, 9, 529–536, DOI:10.1007/s00190-010-0391-5, 2010. (ID:14988)
  • Dobslaw, H., Dill, R., Grötzsch, A. Brzezinski, A., Thomas, M.: Seasonal polar motion excitation from numerical models of atmosphere, ocean, and continental hydrosphere. Journal of Geophysical Research, DOI:10.1029/2009JB007127, 2010. (ID:15342)
  • Dobslaw, H., Thomas, M.: Numerical simulations of short-term non-tidal ocean mass anomalies, In: Flechtner, F. Gruber, T., Güntner, A., Mandea, M.,Rothacher, M., Schöne, T., Wickert, J. (eds.), System Earth via Geodetic- Geophysical Space Techniques, Springer, Heidelberg, 119-129, DOI:10.1007/978-3-642-10228-8_10, 2010. (ID:15149)
  • Saynisch, J. and Wenzel, M. and Schröter, J.: Assimilation of Earth rotation parameters into a global ocean model: length of day excitation. Journal of Geodesy, p 1-7, doi = 10.1007/s00190-010-0416-0, 2010. Abstract
  • Thomas, M., Dobslaw, H.: Contributions of Numerical Simulations of Atmosphere-Hydrosphere Dynamics to the Interpretation of Geodetic Observations. Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract G32A-03 (invited), 2007.
  • Dobslaw, H., Thomas, M., Grötzsch, A.: Regional contributions of atmosphere and oceans to transient changes of the Earth's rotation, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract G42A-08, 2007.
  • Thomas, M., Soffel, M., Drewes, H.: Earth rotation-theory and analysis. In: J. Müller, H. Hornik (eds.), National Report of the Federal Republic of Germany on the Geodetic Activities in the Years 2003 – 2007. XXIV General Assembly of the International Union for Geodesy and Geophysics (IUGG) 2007 in Perugia/Italy. Dt. Geod. Komm., Reihe B, 315, 90–93, 2007.

Poster presentations:

  • Androsov, A. and Schröter, J., Brunnabend, S. and Saynisch, J.: Assimilation of Earth rotation parameters into a global ocean model (FESOM), Geophysical Research Abstracts, Vol. 14, EGU2012-7504, Vienna, Austria, 2012.
  • Jan Saynisch, J.; Maik Thomas, M.: COMBINING GEODETIC OBSERVATIONS WITH A MODEL OF OCEAN DYNAMICS - AN ASSIMILATION APPROACH. Ocean Science Meeting, Salt Lake City, USA, 2012
  • Androsov, A., Schröter, J., and Saynisch, J.: Assimilation of Earth Rotation Parameters in an ocean model. European Geosciences Union, General Assembly 2011, Vienna, Austria, 2011
  • Saynisch,J. and Thomas, M.: Assimilation of Earth rotation observations with a global ocean model. European Geosciences Union, General Assembly 2011, Vienna, Austria, 2011
  • Saynisch, J., Wenzel, M., Schröter, J.: Assimilation of Earth Rotation Parameters into a global ocean model: Governing physical mechanisms. Geophysical Research Abstracts, EGU General Assembly 2010, 12, EGU2010-2661, 2010. (ID:14884)
  • Dobslaw, H., Dill, R., Brzezinski, A., Thomas, M.: Regional contributions to seasonal and inter-annual polar motion variations from atmosphere, ocean and continental hydrosphere. Geophysical Research Abstracts, EGU General Assembly 2010, 12, EGU2010-4285, 2010. (ID:14874)
  • J. Saynisch, M. Wenzel & J. Schröter, Sensitivität der Erdrotationsparameter gegenüber polarem Süßwassereintrag. Posterpresentation, Geodätische Woche Leipzig, September 2007. Not barrier-free file. Download (pdf/1054 KB)

Oral presentations

  • Saynisch, J. and Dobslaw, H. and Thomas, M.: Consistent and constrained simulations of ocean dynamics - contradiction or challenge? Invited Talk, G52A-01, AGU Fall Meeting, San Francisco, 2011.
  • Saynisch, J.: Assimilation of oceanic-angular-momentum observations. “Uncertainty Analysis in Geophysical Inverse Problems“, Lorentz Center Leiden, NL, 10, November 2011.
  • Thomas, M., Saynisch., J.: Joint assimilation of GRACE and Earth rotation parameters with a global ocean model.IUGG, Melbourne, Australia, 2011.
  • Saynisch, J. and Thomas, M.: Ensemble Kalman filtering of Earth rotation observations with a global ocean model. European Geosciences Union, General Assembly 2011, Vienna, Austria, 2011
  • Dobslaw, H., Saynisch, J.: Estimating Ocean State Variables From Geodetic Observations: Seasonal Variations In Total Ocean Mass, And Beyond. QuGOMS'11. The 1st International Workshop on the Quality of Geodetic Observation and Monitoring Systems, Invited Talk, Munich, Germany, 2011
  • Thomas, M., Dill, R., Dobslaw, H.: Numerical model simulations for the interpretation of geodetic monitoring data. Joint GGOS/IAU Science Workshop “Observing and Understanding Earth Rotation”, Shanghai, China, 27 October 2010.
  • Thomas, M., Dobslaw, H., Dill, R.: Operational model simulations of atmosphere-hydrosphere dynamics for analysis and prediction of Earth rotation parameters. Joint GGOS/IAU Science Workshop “Observing and Understanding Earth Rotation”, Shanghai, China, 26 October 2010.
  • Saynisch, J.: Assimilation of Earth rotation observations into a global ocean model: Ensemble KF vs. 4D-Var. DAMES’ 2010 - Data Analysis and Modelling in Earth Sciences, Lissabon, Portugal, 24 September 2010.
  • Thomas, M., Sasgen, I., Dobslaw, H., Saynisch, J.: Beobachtung und numerische Modellierung des globalen Wasserkreislaufs. 8. Herbstschule System Erde, Erkundung vom Erdkern bis zum All, GFZ Potsdam, 12 November 2009.
  • J. Saynisch: Stand der EOP/LSG-Assimilation am AWI. Statusseminar DFG Forschergruppe FOR 584 “Erdrotation und globale dynamische Prozesse”, Wettzell, 12. – 14.03.2008.
  • Thomas, M.: Atmosphärisch-hydrosphärische Modellsimulationen zur Prozessierung und Interpretation geodätischer Monitoring-Daten. Meteorologisches Kolloquium, FB Geowissenschaften, Freie Universität Berlin, 29 October 2007.
  • Dobslaw, H., Thomas, M., Grötzsch, H.: Numerical models of transient atmospheric and hydrospheric dynamics: benefits for the interpretation of geodetic observations. IUGG XXIV 2007, General Assembly Perugia, Italy, 4 July 2007.
  • Thomas, M.: Erdrotationsschwankungen auf geologischen Zeitskalen. Kolloquium der Dresdner Seniorenakademie für Wissenschaft und Kunst, Dresden, 14 June, 2007.
  • A. Grötzsch, M. Thomas, & H. Dobslaw: Operational estimates of transient hydrospheric effects on Earth rotation parameters. EGU General Assembly, Vienna, April 15 - 20, 2007. Not barrier-free file. Abstract (pdf/4 KB)
  • J. Saynisch: Earth rotation and the oceans's circulation - Arbeiten am AWI. Statusseminar DFG Forschergruppe FOR 584 “Erdrotation und globale dynamische Prozesse”, Dresden, 30. – 31.05.2007.
  • J. Saynisch: Der ozeanische Einfluss auf die Erdrotation. Geodetic Week, Munich, October 10 - 12, 2006

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Modification date: 29 May 2012