Abstract: As one of the major generated place of the Antarctic Bottom Water (AABW), the Weddell Sea is a very important margin sea in Antarctic, its hydrodynamic environmental change and its response has important significance to the global change. Over the past century, the global change characterized by global warming had affected Antarctic and the Southern Ocean. In order to understand the hydrodynamic environmental changes in this region, ²¹⁰Pb dating, grain size parameter and ice-rafted detritus content were analyzed and discussed for a short sediment core of ANT28-D5-6 which was taken in the north of Weddell Sea, south to the South Orkney Islands and east to the Antarctic Peninsula. The results show that the hydrodynamic force of Northern Weddell Sea had significant change in nearly hundred years from 1922 to 2011. During 1922-1972, the Northern Weddell Sea was in a high-energy, high-speed and turbulent hydrodynamic environment, and a large amount of ice raft debris was carried and deposited, which was corresponded well to the relatively low temperature stage of the earth. In the course of them, there were twice hydrodynamic environment weakened events happened during 1930-1936 and 1946-1952. The twice increased events of ice-rafted detritus content in 1939 and 1950 might be related to the longitudinal enhancement of Weddell Gyre, which was caused by 17^th and 18^th Solar Maximum Year. During 1972-2011, the Northern Weddell Sea remained relatively calm and low energy hydrodynamic condition, which was corresponded well to the continual warming up stage of the world. During 1955-1972, it was a rapid transition from the high-energy and turbulent state to the low-energy water dynamic of the Northern Weddell Sea.

Key words: Weddell Sea, hydrodynamic environment, grain size parameter, ice raft debris, ²¹⁰Pb