Mean Sea level variation in the South China Sea from four decades of tidal records in Hongkong

Abstract

Over four decades of contiguous tide gauge data collected at two stations in Hong Kong were analyzed to estimate the mean sea level variation. The detected upward trend is 1.35 ± 0.40 mm/yr (1.22 mm/yr including the correction for postglacial rebound). The estimated rate includes corrections for land subsidence, local atmospheric pressure variations, the local effects due to the relocation of the tide gauge, and various significant long and short periodic variations, detected through spectral analyses, which are due to the tidal and other sources. A pitfall that may influence all tide gauge data analyses is identified and the necessary exploratory statistical tools were developed for detecting its presence.