Compilation and validation of bathymetric data for the South China Sea with an emphasis on shallow region

Bathymetric data with a resolution of 5 min called gbscs5 have been compiled for a shelf region shallower than 200 m in the South China Sea by referring to paper charts, electronic charts, and trackline sounding data. Through a comparison between the new dataset and existing datasets (etopo5, etopo1, gebco08), characteristics of each dataset, including the existence of artificial features derived from erroneous sounding data or a conversion error of depth units, were documented for each dataset. It was found that small-scale bathymetric features observed along the shelf edge in gebco08 bathymetry are bounded by survey lines and were likely to be a spurious figure generated when applying a high-order interpolation scheme. Tidal simulations conducted with changing bathymetries have shown that the newly compiled dataset will produce smaller deviation from observed values than the existing bathymetries. While all four datasets analyzed in this study were found to be suitable for estimating overall tidal features of the South China Sea, a care must be taken when applying the tidal model results to a particular coastal region.