The Changing Characteristics of Submarine Micro-Geomorphology Under Combined Currents and Waves

The most direct manifestation of changes in submarine microtopography is the formation and evolution of different types of microtopography, such as the formation and evolution of sand ripples and potholes. However, accurate measurement of microtopographic changes is extremely challenging. In this study, a set of in-situ observation systems for submarine microtopography was established, and in-situ observations were conducted in the Zhoushan Sea area. The study found that under the action of reciprocating currents, the height of the seabed surface undergoes periodic changes, with a maximum height variation of 10.45 cm. However, at the end of the observation period, only 2.6 cm of sediment deposition was measured. In general, the microtopography in the observation area is controlled by tidal currents, and the morphology of sand ripples is determined by the magnitude and direction of the currents. During high-energy events, the microtopography is influenced by the combined effects of waves and tides, increasing the steepness of sand ripple waves and a decrease in asymmetry coefficient.