Accuracy Assessment of a Seamless Depth Datum Model established on the Basis of the Global Ocean Tide Model

Abstract

Li, J.; Fu, Y.; Tang, Q.; Feng, Y.; Zhou, X., and Liu, X., 2020. Accuracy assessment of a seamless depth datum model established on the basis of the global ocean tide model. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 74-78. Coconut Creek (Florida), ISSN 0749-0208.Construction of a seamless depth datum model is important for the unification of the height datum of the land and chart datum of the ocean. Modern depth datum model is established based on the tide model, and its accuracy depends mainly on the accuracy of the tide model itself. In this paper, the global tide model FES2014 was adopted to construct a lowest normal low water (LNLW) and lowest astronomical tide (LAT) datum model, the resolution was 1/16° × 1/16° in Chinese Sea area (15 °N–42 °N, 105°E–128 °E). Statistical analysis was performed on the distribution of the datum values of LNLW and LAT in the study area, results ranged from -22.72 to -446.74 cm and -23.17 to -448.00 cm, respectively. The difference values between them were in the range of -29.92 to 36.45 cm. Furthermore, 94.0% of the differences were within ±10 cm and 66.4% were positive values, indicating that the surface of LNLW was above the LAT in the study area. Comparison with datum values calculated from 16 tide gauge stations with long-term observations showed that the standard deviation were 13.02 cm and 11.68 cm for LNLW and LAT, respectively.