Pamuteran is one of the coral reef ecosystem regions in northern Bali. One of the factors that affect the growth of coral reefs is salinity. Multispectral satellite-based mapping is the only feasible method for determining the distribution of water salinity. This study aims to determine the field accuracy value of empirical salinity algorithms developed in Indonesia for the sentinel 2-A multispectral image. The estimated value is then compared to the field measurement value. This study compares the Cilamaya and Cimandiri algorithms for estimating salinity measurement values in the Pamuteran region using Sentinel 2-A imagery on the Google Earth Engine platform. In accordance with the Cimandiri algorithm and the results of the analysis, the salinity distribution value ranges from 40 to 44⁰/₀₀, but in some regions, it reaches 68⁰/₀₀. While the Cilamaya algorithm displays a salinity distribution between 22.5 and 25⁰/₀₀, it displays a significant number at 12.5⁰/₀₀ in certain regions. The distribution of salinity values obtained in the field indicated a range between 32.18 and 32.34⁰/₀₀. In comparison to the Cimandiri algorithm, the Cilamaya algorithm yields estimation results that are closer to the salinity data collected in the field.

Keywords: coral reef, salinity, sentinel 2-A, accuracy value of salinity