Role of Horizontal Processes in Upper-Ocean Prediction: A Forecast Simulation in the Sea of Japan

摘要

Present-day, operational, upper-ocean, thermal-structure forecast models consist of mixed layer models with local wind-generated horizontal and vertical advection. To extend their applicability into dynamically active regions, e.g., western boundary current regions, the next generation ocean models are envisioned to include mesoscale advection provided by high horizontal resolution circulation nowcast and, eventually, forecast models. This study considers the impact of this additional component for advection in a representative dynamic ocean region. Four experiments were performed using a modified version of an operational, upper-ocean, thermal prediction model. Each consisted of a series of daily, 72-hour-duration, upper-ocean hindcasts and was conducted for 4 weeks during the warming season in the Sea of Japan. The first experiment used an Nx1 dimensional mixed-layer model with no horizontal and vertical advection. The 3rd, repeated the 2nd, with the addition of a fixed geostrophic component to the horizontal advection. The 4th allowed daily variation of the geostrophic component through each 3-day forecast. Statistical measures applied to the results indicated a small but statistically significant increase in forecast skill due to the addition of the nowcast mesoscale advection. (edc)