Swells can travel thousands of kilometers. The source of distant-source swells propagated from the North Pacific Ocean into the China Sea area has not yet been clarified. In this study, WAVEWATCH III was used to calculate the wave fields in two domains of the Northwest Pacific Ocean (WNP) and the North Pacific Ocean (NP), respectively. The swell tracking algorithm was improved to determine the source of distant-source swells. Comparative analysis of bulk wave parameters across two computational domains clearly reveals the propagation of distant-source swells into the China Sea during the autumn and winter seasons. Wave spectra at selected points contain information about these far-field swells, and the algorithm identifies that the far-field swells mainly originate from two source locations in the middle and low latitudes of NP. Frequent changes in the wind direction of the storm system at the swell source location are consistent with the shorter duration of the far-field swells. This work provides a basis for future research on coastal swell forecasting and swell warning.

Due to the significance of waterway depths in river development, the effect of the evolution of bars and troughs on waterway expansion has always been interesting for river management and water depth conservation. In this study, the aim is to expand the waterway dimensions of the Jingjiang Reach, and it is necessary to determine how river evolution processes relate to its potential for waterway depth improvement and navigation hindrances. Therefore, the sedimentation, hydrological, and terrain data of the Jingjiang Reach from 1950 to 2020 were analyzed to elucidate the aforementioned relationships After the commissioning of the Three Gorges Dam, it was found that the scour of the low flow channel has accounted for 90.95% of all scour in the Jinjiang Reach. Furthermore, its central bars and beaches have shrunken by 9.4% and 24.9%, respectively, and 18.3% as a whole. In view of the bed scour and waterway regulation projects that occurred in the Jingjiang Reach, we investigated the continuity of a 4.5 m × 200 m × 1050 m (depth × width × bend radius) waterway along the Jinjiang Reach, and found that it is navigationally hindered over 5.3% of its length. Furthermore, part of the Jingjiang Reach is an important nature reserve, and there are also many water-related facilities in this area; hence, these conditions inhibit the implementation of waterway deepening projects. As a result, the study findings indicate that there are many challenges with regards to increasing the waterway depths of the Jingjiang Reach.