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 realize over ocean surface an equipotential surface of the GOCO02S Earth gravity field model (Goinginger et al. 2011).

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 http://www.dgfi.badw.de/?333)

The iDOT-profiles are distributed here in the hope that they will be useful, but DGFI provides these data “as is” without warranty, expressed or implied, as to the use or appropriateness of the iDOT-profiles, and there are no warranties of merchantability or fitness of these data for a particular purpose or use.

The iDOT data is structured according to the hierarchy

  mission  1:n    cycle    1:m    pass
 
and is available  on the anonymous ftp

   ftp://ftp.dgfi.badw.de
  
in directory

   pub/iDOT/gaussFilter.69km
  
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  ccc.idot.69.nc 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 www.unidata.ucar.edu/software/netcdf/ ).

Bosch W., Savcenko R.: On Estimating the Dynamic Ocean Topography. In: Mertikas S.P. (Ed.): Gravity, Geoid and Earth Observation. Springer IAG Symposia, Vol. 135, 263-269 , 2010
Bosch W., Savcenko R., Luz R. T.: The absolute dynamic ocean topography    (ADOT) – estimation and application. Proceedings of the ESA Living Planet Symposium, Bergen, Norway, ESA Publication SP-686 (CD-Rom), 2010
Dettmering D. and W. Bosch. „Global Calibration of Jason-2 by Multi-Mission    Crossover Analysis“. Marine Geodesy 33, Nr. sup1 (2010): 150–161.
Goiginger H., et al.: The combined satellite-only global gravity field model GOCO02S. Presented at the 2011 General Assembly of the European    Geosciences Union, Vienna, Austria, April 4-8, 2011.