Estimation of regional sea level change in the Pearl River Delta from tide gauge and satellite altimetry data

The present study proposes a reconstruction of regionally consistent sea level anomalies in the Pearl River Delta (PRD) over the period 1959–2011. Spatial empirical orthogonal functions (EOFs) derived from satellite altimetry dataset and the corresponding time series of tide gauge records were combined to generate regional sea level anomalies. Based on these datasets, regionally consistent sea level anomalies (RCSLA) are reconstructed using a dimension-reducing method known as principal components analysis. The results show that the accuracy of reconstruction is sensitive to the number of the available tide gauge records, however no significantly effect of the length of the records is observed. The results also indicate that the EOF reconstruction method addresses issues such as the relatively short-term coverage of satellite altimetry data and the sparse and discontinuous nature of tide gauge records, demonstrating the applicability of this technique in investigation of long-term sea level change. Both river flow and El Niño event have considerable impacts on sea level variability in the PRD.