Modeling and Application of Global Maritime Transport Accessibility Based on Probability Distribution

The study of sea area accessibility is often overlooked despite the fact that vessel routes' density at sea can reflect human activity patterns. Using AIS point data for 2014 and 2018, this paper constructed global daily vessel routes and applied the kernel density estimation method to obtain the probability distribution function of route density for over 700,000 sea grids under a global 0.25 degrees regular grid. An accessibility model for sea areas was then proposed and applied to the grid, resulting in the accessibility assessment of global sea areas in 2014 and 2018. The results indicated that the average global maritime accessibility value increased from 5.2% in 2014 to 14.4% in 2018. Accessibility to various international trade routes, such as those through the Cape of Good Hope and polar regions, significantly increased. However, accessibility to sea areas such as the Mediterranean and sea areas near the Pacific Islands decreased. This study explored the temporal and spatial variation of maritime traffic accessibility, which could enhance our understanding of global vessel activity characteristics and guide maritime rescue resource allocation, marine species protection, and marine spatial planning.