Monsoon circulation and its impact on bedload transport in the Qiongzhou Strait and adjacent seas based on SCHISM

The data employs the SCHISM model to simulate monsoon circulation, tidal currents, and sediment transport in the Qiongzhou Strait and adjacent seas.In this study, a three-dimensional numerical simulation system for the Qiongzhou Strait and adjacent seas, named SCHISM, is established. The system is driven by the altimeter-assimilated TPXO8 tidal model as tidal boundary conditions and validated using the water levels from surrounding tide stations to confirm the mod-el's tidal level. The SCHISM model employs an unstructured triangular grid covering the northwestern South China Sea (105–113° E, 16–22° N), with 49,221 nodes and 91,827 elements. Bathymetry is derived from SRTM15+ (15 arc-second resolution) and Chinese nautical charts. Mesh resolution varies from 200 m in the Qiongzhou Strait to 15 km at the open boundary. The model uses 40 verti-cal layers: 20 sigma layers for depths ≤40 m and z-levels (5–200 m thick) for depths of 40–2200 m.To simulate the wind-driven circulation in the Qiongzhou Strait under varying monsoon conditions, this study utilized the fifth-generation atmospheric reanalysis dataset ERA5 published by the European Centre for Medium-Range Weather Forecasts (ECMWF) , establishing wind stress boundary conditions based on this dataset. The dataset provides comprehensive hourly estimates of various climatic variables, in-cluding atmospheric, terrestrial, and oceanic parameters, with a spatial resolution of 0.25 degree. To achieve the aims of this study, data on sea surface wind speed compo-nents (u10, v10), atmospheric temperature, relative humidity, and sea surface pressure for the period between 1980 and 2023 were downloaded, focusing specifically on the Qiongzhou Strait and adjacent seas. Furthermore, to better capture and analyze the long-term effects of monsoon changes on the circulation in the Qiongzhou Strait, ERA5 data from February and August were used for winter and summer monsoon in the simulations.This study utilizes vertical profiles of velocity from HYCOM to establish.