[A-CG40] Earth System Observation Impacts on Climate and Ocean Predictions

[ACG40-P03] Intercomparison and Ensemble of Coastal Ocean Prediction Models in Japan: A Case Study in the Goto-nada

*Teiji In¹, Shoichiro Kido², Shun Ohishi³, Nariaki Hirose⁴, Takashi T. Sakamoto⁵, Naoki Hirose⁶ (1.Japan Marine Science Foundation, 2.Japan Agency for Marine-Earth Science and Technology, 3.RIKEN, 4.Meteorological Research Institute, Japan Meteorological Agency, 5.Ocean Eyes Co., Ltd., 6.Research Institute for Applied Mechanics, Kyushu University)

Keywords:ocean model, data assimilation, coastal ocean dynamics, multi-model ensemble, Goto-nada

Despite considerable advancements in ocean data assimilation and prediction systems, the diversity and inconsistencies among them introduce uncertainties for users. To address this issue, we conduct an intercomparison and ensemble project involving major coastal ocean prediction systems in Japan, including DREAMS, JCOPE, LORA, MOVE, and SEAoME. As an initial step, we selected a small, representative zone to facilitate a detailed comparison of discrepancies among these ocean data assimilation models. We selected the Goto-nada, located between Kyushu and the Goto Islands, as an ideal study area. The models differ in spatial resolution, topography, geometry and other factors. To ensure consistency in intercomparison and ensemble calculations, we standardized the model outputs by regridding to a 0.1-degree horizontal resolution and interpolating vertically to align the depth levels, while applying 5-day averaging to unify the temporal resolution. In addition to typical indicators such as temperature, salinity, current velocity, and sea surface height, our analysis places particular emphasis on the depth of the sea surface mixed layer. This study elucidates the spatial and temporal characteristics of each model and provides indices to characterize the target zone. We plan to compare the results with in situ observations and remote sensing data to assess the accuracy and reliability of the model outputs. In the future, we aim to increase the resolution and extend this approach to other coastal regions around Japan.