A Meteo-Hydrological Fusion Index for Composite Marine Environmental Risk Assessment: Methodology and Application to Mokpo Coastal Waters

With the growing interest in Maritime Autonomous Surface Ships (MASS), numerous risk-assessment models have been proposed for route planning and hazard avoidance during navigation. Existing models, however, generally share two limitations. First, many assess risk from information such as vessel traffic and therefore do not adequately reflect the marine weather and sea state itself. Second, they often consider only one or two factors, such as wave height or wind, and even when several factors are merged into a single value, it is difficult to trace back why the result is dangerous. To overcome these limitations, this study proposes a Meteo-Hydrological Fusion Index (MHFI) that combines five environmental factors—wave height, swell period, current, wind, and visibility—into a single risk value. Each factor is first mapped to a 0–4 risk score, and the three highest scores at a given location are then combined by a weighted sum. This summarizes composite risk in a single value while preserving the ranking of the factors that produced it, so the result remains traceable. Applying the index to the coastal waters of Mokpo, we confirmed that the dominant factor behind a given risk grade varies with time and location, and that a rapid, area-wide rise in risk over a short period can be captured by a single indicator. We further show how risk varies along the main fairway and how the index can be overlaid on a display panel. These results indicate that the MHFI could serve as a decision-support layer in an S-100-based digital navigation environment.