Reconstructing estimates of ocean steric sea-level rise from sparse ocean data sets

John A. Church^1,2, Catia Domingues¹, Neil J. White^1,2 and Susan Wijffels¹

¹CSIRO Marine and Atmospheric Research
²Antarctic Climate and Ecosystems Cooperative Research Centre

Ocean thermal expansion is an important component of sea-level rise. Estimates of ocean thermal expansion for the last five decades have been produced from the comparison of individual sections, objective mapping of historical data sets and ocean reanalysis experiments. However, the combination of the available estimates of ocean thermal expansion and other contributions to sea-level rise have not adequately explained the observed sea-level rise estimated from tide gauge data.

One potential explanation is that current ocean thermal expansion estimates are biased because of sparse data coverage, particularly in the southern hemisphere. Reduced space optimal interpolation techniques have been used for reconstructing historical sea surface temperature, atmospheric pressure and sea-level time series. We are developing procedures for applying reduced space optimal interpolation to sparse oceanographic data sets of steric height.

Initial results for the post 1993 period will be presented and compared to other estimates for this period.