Simulation and EOF analysis of ocean circulation in the gulf of Thailand

Ocean currents are one of the most important factors in marine environment. Ocean currents affect the availability of nutrients, food and the spread of eggs and larvae for marine animals. Besides, the ocean currents are also the main driven forces for sediment transport and coastal processes which are the key factors for the coastal erosion and accretion as well as marine pollution. Thus, analyzing ocean current information, especially in shallow seas, will benefit ocean scientists in deriving new knowledge on ocean processes and variability, fishery/aquaculture scientists in incorporation the larval distribution of fish into improved management plans and management authorities in deriving and implementing more effective coastal management schemes. In this work, we first aim at simulating the ocean circulation in the Gulf of Thailand. The region is composed of complex coastlines and seafloor topography. This can result in complicated ocean currents. To this end, we employ the unstructured grid Finite-Volume Coastal Ocean Model (FVCOM) to handle such issue with its geometric flexibility capability. For the model validation purpose, we use the surface currents data measured by high frequency surface wave radar (HFSWR) from Geo-Informatics and Space Technology Development Agency (GISTDA). We have found that the RMS error shows the model output agrees with the observation well. Besides, we also investigate the overall characteristic of the simulate currents together with the observed currents as well. This is done through the Empirical Orthogonal Function (EOF). The results also indicate that the dominant characteristic of ocean currents from simulation is analogous to the observation. To sum up, these results justify that the model can be predicted and explained the behavior of ocean currents precisely and realistically. Secondly, we also analyze the EOF pattern of the ocean circulation in order to provide insight into the dynamics and spatial structure of the ocean currents in the Gulf of Thailand.