Discussion on the Seiche in the Longkou Harbour and Its Causes of Formation

Based on the seiche data over 23 years ( 1964—1986 ), the paper discusses the amplitude, frequency, period and duration of the seiche in the Longkou Harbour, give the various synoptic situations and wind fields that lead to the seiche, analyses the contributions of different meteorological factors to the seiche and discusses the causes of formation of the seiches of big and outsized amplitudes. Analytical results indicate that the wind field variatoins are directly responsible for the seiche in the Longkou Harbour and that the seiches of big and outsized amplitudes of about 100 cm and 150 cm are the combined effect of the particular geographic environment of the harbour, and the fulmiating gale toward the harbour in the harbour and the nearby large sea area, especially the sudden accumulation of the strong thunderstorm gale and ground swell and the inertial oscillation of seawater in the harbour. Such seiches are of greater danger.