摘要
本文根据 30多个古气候分析实例 ,探讨中国热带MIS 3气候波动的相位特征、变幅特征和周期特征。MIS 3为回暖期 ,曾出现早、晚 2个暖期 ,晚期比早期更暖。MIS 3的气候与现今的气候相比较 ,东部热带以热湿为主 ,年均温比今高 1°～ 2℃或 2°～ 2 .5℃ ,年降水量比今多 70 0mm或 40 0～ 50 0mm ;西部热带以凉湿为主 ,年均温与今相似或约低 1 .5℃ ,年降水量比今多 70 0mm左右。MIS 3期间出现 2个冷—暖—冷的旋回 ,平均周期为 1 7.5ka,这与岁差周期大体相符。中国热带MIS 3的气候波动不仅有万年尺度的地球轨道周期 ,也有千年尺度的周期 ,后者与太阳辐射总量本身的变化有关。
According to paleoclimatic analyses of about thirty examples related to oxygen isotope, spore pollen, magnetization, mamalia fauna, stalagmite, diatom, coral reef and mangrove, the correspondence between the phases of climatic variation in China's tropical areas and that of global change during MIS 3 can be established. The MIS 3 was a warming return stage with two warm phases and the level of warming return was inferior to that of the last interglacial period or postglacial period. However, the later warm phase was warmer than the former, which is different from global change. It is deduced that the periodical fluctuation of climate in China's tropical areas is controlled not only by earth orbital parameters but also by monsoon circulation. With influence of two monsoon systems, the East Asian monsoon and the South Asian monsoon, the climatic fluctuation during MIS 3 showed a regional differentiation. Compared with the present climate, the paleoclimate was mainly hot and humid in the eastern tropical areas but cool and humid in the western tropical areas. In the eastern tropical areas the annual temperature in the warming phases of MIS 3 was 1°～2℃ or 2°～2.5℃ higher than the present temperature and the annual precipitation increased by 700mm or 400～500mm. In the western tropical areas the annual temperature was equal to or about 1.5℃ lower than the present temperature, but the annual precipitation increased by about 700mm. The two cycles of cooling-warming-cooling, each with a periodicity of about 17.5ka, indicate that the periodicity of climatic fluctuation during MIS 3 in China's tropical areas was roughly corresponding to the periodical change of astronomical precession of 19ka or 23ka. Also, data from several high resolusion profiles show that except the orbital scale periodicity as long as ten thousand years or more, there were millenium scale climatic changes such as Dansgaard/Oeschger sudden warming events No.3～No.18 and Heinrich sudden cooling events No.3～No.5. The mechanism for these millenium scale events was probably related to change of the solar constant itself, because it has variation cycles of 1 000a, 2 500a and 2 700a. =
出处
《第四纪研究》
CAS
CSCD
北大核心
2003年第1期77-82,共6页
Quaternary Sciences
基金
国家自然科学基金 (批准号 :4 0 0 710 11和 4 97710 10 )资助项目
