Ozeanwirbeldynamik analysiert anhand von TOPEX-JASON Tandem Altimeterdaten und numerischen Zirkulationsmodellen
Zusammenfassung der Projektergebnisse
In the project "TANDEM" we investigate the usefulness of remotely sensed surface geostrophic velocities versus the more conventional altimetric sea surface heighl for determining ocean mean flow and eddy dynamics. Orbiting of the JASON and TOPEX-POSEIDON (T/P) satellites in parallel during the TANDEM mission allowed for calculation of surface velocities from the sea surface height (SSH) data. We assimilate such derived surface velocity data along their virtual tracks into the Finite Element Ocean Model (FEOM) of North Allantic developed al the Alfred-Wegener Institul (AWI). This model uses continuous linear representation for the horizonlal velocity, surface elevation, lemperature and salinity, and solves the standard set of hydrostatic ocean dynamic primitive equations. Assimilation is done using the Singular Evolutive Interpolated Kalman (SEIK) Filter. For comparison, assimilation of only the altimetry data from the TANDEM mission is also performed. We investigate assimilation results depending on whether the observed field or its gradient is assimilated. There is no conclusive evidence that either of the two methods has an advantage. Both assimilation techniques seem not to improve the model significantly. Two possible developments may change this early conclusion: Enhancing the model resolution in the areas that are particulary problematic or the application of localization in the context of Kalman Filtering. First attempts to modify the SEIK algorithm to increase the rank of the inversion and improve the local analysis are encouraging.
Projektbezogene Publikationen (Auswahl)
- 2006: Treatment of Observation Error due to Unresolved Scales in Atmospheric Data Assimilation. Monthly Weather Review, 134, No. 10, 2900-2915
Janjic, T. and S. E. Cohn
- (2007).Assimilation of sea-ice velocity in a Finite Element Sea-Ice Model, North Atlantic Subpolar Gyre Workshop, Kiel, Germany, 19-21 March 2007
Rollenhagen, K., Timmermann, R., Janjic, T., Schröter, J.
- (2007).Estimating circulation in Antarctic Circumpolar Current via sequential assimilation of multi-mission altimetry data, Joined International Symposium GSTM/ DFG-SPP1257, GFZ Potsdam Germany, 15-17 October 2007
Skachko, S., Danilov, S., Janjic, T., Schröter, J., Sidorenko, D.
- (2007).FEOM, an unstructured mesh Finite Element Ocean Model, European Geosciences Union General Assembly, Vienna, 15-20 April
Schröter, J., Sidorenko, D., Harig, S., Wang, Q., Timmermann, R., Rollenhagen, K, Boening, C , Janjic-Pfander, T., Huerta-Casas, A.
- (2007).Hybrid SEIK algorithm for oceanographic data assimilation, lUGG XXIV 2007 Perugia Italy
Janjic, T., Skachko, S., Danilov, S., Schröter, J.
- (2007).Sea Ice Drift Assimilation in a Finite Element Sea Ice Model using a Singular Evolutive Interpolated Kaiman Filter, General Assembly of the European Geophysical Union, Vienna, Austria, April 2007
Rollenhagen, K., Timmermann, R., Janjic, T., Schröter, J.
- (2007).Sea Ice Drift Data Assimilation in a Finite Element Sea Ice Model using a Singular Evolutive Interpolated Kaiman Filter, IICWG Workshop on Sea Ice Modeling and Data Assimilation, Oslo, 14-16 May 2007
Rollenhagen, K., Timmermann, R., Janjic, T., Schröter, J.
- (2008).FEOM, status and plans, Seventh International Workshop on Unstructured Grid Numerical Modelling of Coastal, Shelf and Ocean Flows, September 17-19 2008, Halifax, Canada
Schröter, J., Danilov, S., Sidorenko, D., Wang, Q., Timmermann, R., Nerger, L., Huerta-Casas, A., Mamann, S., Bning, C, Janjic, T., Behrens, J., Androssov, A., Richter, R, Hiller, W., Harig, S., Brunnabend, S.
- (2008).On domain localization in ensemble based Kaiman Fiter algorithms, WWRP Workshop, 10-13 November 2008, Buenos Aires, Argentina
Janjic, T., Nerger, L., Schröter, J.
- 2008: Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model. Ocean Sci., 4, 307-318
Skachko, S., S. Danilov, T. Janjic, J. Schröter, D. Sidorenko, R. Savchenko and W. Bosch
- (2009) Assimilation of geostrophic velocity and height data into a finite element ocean model, EGU 2009, Vienna
Janjic, T., Nerger, L., Schröter, J., Danilov, S.
- (2009).Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model, EGU 2009, Vienna
Skachko, S., Janjic Pfander, T., Danilov, S., Schröter, J., Sidorenko, D., Savcenko, R., Bosch, W.
- 2009: Assimilation of sea ice velocity data in a Finite element Sea Ice Model with the. Singular Evolutive Interpolated Kaiman Filter. J. Geophys. Res., 114, C05007
Rollenhagen, K., R.Timmermann, T. Janjic, J. Schröter and S. Danilov
(Siehe online unter https://doi.org/10.1029/2008JC005067)
