Impact of Tropical Cyclones on Sediment Dynamics on the Inner Shelf of the East China Sea: Path-Specific Effects and Superposition Analysis

Tropical cyclones (TCs), as highly dynamic and spatially asymmetric synoptic events, can trigger distinct responses in regional sediment dynamics due to their diverse paths. Using numerical modeling, we systematically compared sediment dynamics on the inner shelf of the East China Sea (ECS) under varying TC path categories. Via statistics from three best-track archives, six primary clusters of TCs impacting the inner shelf were identified, most of which induce notable asymmetric sediment dynamic responses. Based on the relationship between TC paths and sediment redistribution patterns, these clusters can be further categorized into three groups. The first group, exerting the most significant impact, triggers substantial downwind sediment transport southwestward along the shelf and seaward south of 28°N, resulting in offshore deposition between 26 and 28°N. The second group transports sediment along the shelf within the 30-m isobaths and deposits it near the Taiwan Strait. The last group, characterized by a single TC path but occurring most frequently, redistributes sediment southward from the muddy belt center with limited impacts in the northern regions. Based on path superposition analysis, we illustrated that TCs can cause severe erosion within the 30-m isobaths and form offshore deposition between 26 and 28°N. The TC-induced sediment redistribution could be the primary driver of cross-shelf transport near 27°N, aligning well with the offshore depocenter south of the ECS muddy belt. This study highlights the critical role of TC paths in sediment dynamics and provides insights into their impacts on the formation and subsequent evolution of muddy deposits on continental shelves.