近百年来南极威德尔海北部水动力环境演变

The hydrodynamic environmental change in North Weddell Sea of Antarctic over past 100 years

南极威德尔海水动力环境的变化及其对全球变化的响应有着重要的意义,近百年来以全球变暖为特征的全球变化已经影响到该地。对南极威德尔海北部ANT28-D5-6短柱沉积物进行了210 Pb测年、粒度参数和冰筏碎屑物含量的测试分析。结果显示威德尔海北部在近百年时间内(1922—2011年)水动力环境发生了显著的转变。在1922—1972年间,威德尔海北部处在高能高速动荡的水动力环境,并携带沉积了大量的冰筏碎屑物,对应了全球温度变化相对较低的阶段。但在1930—1936年间和1946—1952年间发生了2次水动力减弱事件。1939年和1950年两次冰筏碎屑物含量的增加可能与太阳活动峰年引起的威德尔环流经向增强有关。1972—2011年威德尔海北部处在较为平静的弱能状态,对应了全球气温持续升温的阶段。1955—1972年威德尔海水动力环境处在从高能动荡的状态向低能静水状态快速过渡的阶段。

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 17th and 18th 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.