Analyse hydrographischer Schnitte mit Satellitenaltimetrie
Losch, Martin
Universität Bremen: Physik/Elektrotechnik
oceanography, hydrography, sea-surface height, satellite altimetry, geoid, inverse methods, adjoint method
Dedicated satellite missions that will lead to high precision, high resolution geoid models are planned and/or in preparation. In this study, a particular method is presented that allows the use of sea surface height data, that is consistent with its error covariance. A first test of the model in a scenario with a small data set demonstrates some of the model´s characteristics. One has to handle the mathematical under-determination of the model by introducing sufficient prior information about the state of the ocean. This independent information could be taken from a hydrographic atlas. Twin experiments with a data set taken from a general circulation model of the FLAME group reveal the importance of improved geoid models for estimating the flow field along a hydrographic section. When the sea surface height data is weighted according to the error estimates of the future geoid models GRACE and GOCE integrated transports of volume and temperature can be determined with an accuracy that is improved over the case with no sea surface height data by 55%. With the error estimates of the currently available geoid model EGM96 the reduction of the estimated errors does not exceed 18%. The inverse model estimates integrated volume transports through the WOCE hydrographic section SR3, one of the choke point sections of the Antarctic Circumpolar Current, of 145-166 Sv. These values agree with the ones found by other authors. The error estimates range from 13 Sv without to 11 Sv with sea surface height data. The sea surface height data is referenced to the EGM96 geoid model and weighted according to its error covariance. Sea surface height data and an estimate of the sea surface height by the model are found to deviate from each other by more than the error estimates.
Analyse hydrographischer Schnitte mit Satellitenaltimetrie