Evaluation of Regional Tidal Model on the West Coast of North Sumatera Province

Abstract

Abstract On the west coast of North Sumatra, the availability of tidal data has not been optimal, hence a tidal model is required to describe marine information. The regional tidal model (developed by Indonesia Geospatial Agency, hereafter called as BIG model) was built from multi-mission altimetry data that was assimilated with 138 tide stations (TS) data over the Indonesian ocean before 2018. The research aimed to evaluate the BIG model using TS data that was built after 2018, namely, TS.Barus, TS.Sirombu and TS.Batahan at 2019-2020. The research method is to calculate the Root Mean Square, Root Sum of Squares, Root Sum of Squares of the In-phase and Quadrature, and Discrepancy (D) of 8 harmonic constants (HC: M2, K1, S2, O1, P1, N2, K2, Q1). Also calculated the correlation between BIG model and prediction from TS data in January 2021. According to HC analysis, the smallest amplitude difference in K1 TS.Barus is - 0.0077m, while the largest is 0.0278m in M2 TS.Batahan.Q1 has the least RMS at 0.0039m, while M2 has the most at 0.035m.The Discrepancy (D) between the BIG model and TS data is 5.5609 percent, showing that the tidal model is reliable. The correlation value between BIG model and predicted observational data shows a strong positive relationship, indicated by an R value between 0.996 - 0.998.