Instantaneous Dynamic Ocean Topography Profiles (iDOT)

Data: (Reference: GOCO02S) (Reference: GOCO03S)


Dr. Denise Dettmering

When using the data, please cite:

Bosch W., Savcenko R.:On Estimating the Dynamic Ocean Topography. In: Mertikas S.P. (Ed.): Gravity, Geoid and Earth Observation. IAG Symposia, Vol. 135, 263-269, doi:10.1007/978-3-642-10634-7_34, 2010.


The "profile approach", developed by Bosch & Savcenko (2010) estimates the dynamic ocean topography (DOT) along individual profiles observed by nearly all satellite altimeter missions operating since end of 1992. The instantaneous DOT profiles (iDOT) are derived as deviation between the actual sea surface heights h and the geoid heights N which describe an equipotential surface based on the Earth gravity field models GOCO02S/GOCO03S. Both, h and N are consistently filtered by a Gauss-type filter with a half width of 69 km. For more details see Bosch & Savcenko (2010). This way, the iDOT profiles realize smoothed snapshots of the ocean topography and may be used to characterize the temporal evolution of the DOT since late 1992. Moreover, as the data of all satellite altimeter missions have been carefully harmonized and cross-calibrated in advance (e.g. Dettmering & Bosch 2010), it should be possible to merge and combine iDOT profiles of any mission in order to improve the spatial and temporal resolution. Due to the filter length of 69 km the IDOT profiles carry the signature of meso-scale pattern and can be taken to illustrate evolution and kinematics of Eddies and of the geostrophic velocity field (see animations at the DGFI project web page). The iDOT data is structured according to the hierarchy 

mission  1:n    cycle    1:m    pass

for Envisat, ERS-1, ERS-2, Topex, Topex-EM, Poseidon, Jason-1, Jason1-EM, Jason-2 and GFO. The pass files follow the naming convention where ccc stands for the cycle. The pass files are given in netcdf (Network Common Data Form), a self-describing, machine-independent data format developed by unidata (see ).

Further details:

DGFI project web page

Bosch W., Savcenko R., Dettmering D., Schwatke C.: A two-decade time series of eddy-resolving dynamic ocean topography (iDOT). In: Ouwehand L. (Ed.) Proceedings of "20 Years of Progress in Radar Altimetry", Sept. 2012, Venice, Italy, ESA SP-710 (CD-ROM), ISBN 978-92-9221-274-2, ESA/ESTEC, 2013.