longshore drift
noun [ U ] environment specialized uk/ˌlɒŋ.ʃɔː ˈdrɪft/ us/ˌlɑːŋ.ʃɔːr ˈdrɪft/
沿岸漂移（海浪以与海岸平行的方向，或以与其成一定角度的方向运动，推动沙粒和小石子等沿着海岸前进）
the movement of sand and small stones, etc. along the coast by waves travelling parallel or at an angle to the coast