%0 Journal Article
%T THE MILANKOVITCH THEORY OF PLEISTOCENE GLACIAL CYCLES: CHALLENGES AND CHANCES<br>米兰科维奇冰期旋回理论:挑战与机遇
%A Ding Zhongli
%A <br>丁仲礼
%J 第四纪研究
%D 2006
%I 
%X Milankovitch theory holds that climatic changes of the Pleistocene have been forced by cyclic variations in summer insolation around 65°N of the northern hemisphere. The signatures originated in this region can be amplified by positive feedbacks and propagated into other parts of the climate system through processes such as changes in atmospheric carbon dioxide concentrations and North Atlantic Deep-Water formation. Oxygen isotopic records of deep-sea sediments have shown that episodic growth and decay of the polar ice sheets of the northern hemisphere was dominated by a period of about 100000 years during the Late Pleistocene. Other climatic records derived from the high and middle latitudes of both hemispheres also have a strong 100000-year period, thus broadly supporting the Milankovitch theory. However, recent studies show that in some parts of the tropical region on the globe, a 20000-year precession cycle is predominant during the Late Pleistocene climate changes, suggesting the importance of local insolation forcing. Phase-relation studies indicate that during the last terminations, the warming of the Antarctica and the equatorial region occurred several thousand years earlier than the melting of the ice sheets of the northern hemisphere. An earlier increase in atmospheric CO2 concentrations has also been recognized for the penultimate termination. These lines of evidence are inconsistent with the ice-volume forcing model that was implied by the Milankovitch theory. Some accurately-dated climate records even show an earlier Last Glacial Maximum in the southern hemisphere relative to that in the northern hemisphere. All these facts mentioned above suggest that the forcing mechanism for the Pleistocene glacial cycle could have been more complicated than that held by the Milankovitch theory.
%K Milankovitch theory
%K glacial cycles
%K climate periodicity
%K phase relationship
%K forcing mechanism<br>米兰科维奇理论
%K 冰期旋回
%K 气候周期
%K 相位关系
%K 动力机制
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=EA07051745CDC8D89D5F01A3A4CFE6A9&aid=1F46046ACAEB701E&yid=37904DC365DD7266&vid=96C778EE049EE47D&iid=94C357A881DFC066&sid=2868AE484E7BAD6B&eid=E5ED9059DE792E50&journal_id=1001-7410&journal_name=第四纪研究&referenced_num=10&reference_num=51