我国中低纬度末次冰消期气候转暖 与高纬度气候变化的关系*

末次冰消期转暖的过程和机制一直是古气候研究的热点,然而对于末次冰消期全球气候在时间、空间上的变化以及热带低纬度地区在其中发挥的作用仍不明确。文章根据我国中低纬度地区的湖光岩玛珥湖、渭南黄土剖面和东海DGKS9603孔沉积物中的植硅体等环境指标的分析,研究了末次冰消期在这些地区的变化特点,并结合古里雅冰芯和南京葫芦洞石笋氧同位素记录与南极BYRD冰芯、北极格陵兰GRIP冰芯氧同位素记录进行了对比。结果表明,各地区转暖的时间并不同步,明显受印度洋季风或东南季风影响的古里雅、湖光岩地区是气候转暖较早的地区,格陵兰地区的快速转暖滞后于我国中低纬度转暖1.5~2.0ka以上。如何理解高纬度和热带低纬度地区气候转暖的差异性问题及其原因和机制有待于更多高分辨率气候记录研究和模型的检验。

TIMING OF THE LAST DEGLACIAL WARMING IN LOW AND MIDDLE LATITUDES OF CHINA: COMPARED WITH BIPOLAR ICE CORE

The process and mechanism of the last deglacial warming have long been the hotspot of paleoclimatological study.However,neither the process nor the mechanism of deglacial warming in low-middle latitude regions has been clear.Here,based on phytolith studies from the Huguangyan Maar Lake,the Weinan loess section and the DGKS9603 core in the East China Sea,combined with other high-resolution paleoclimate records from the Guliya ice core and from the Hulu cave in China,and the BYRD ice core and GRIP ice core in bipolar regions,we try to explore the timing of low-middle latitude and high latitude climate changes during the last deglaciation.By these records,we set up the timing and manner of deglacial warming in low-middle and high latitude as the follows: 1) The deglacial warming manner is different in different records.For example,the BYRD ice core,the Guliya ice core,the Huguangyan Maar Lake,and the Hulu cave record show continuous warming during the deglaciation period,with an about 1000 years duration;while the DGKS9603 core,the Weinan loess section,and the GRIP ice core show an abrupt deglacial warming,with the warming time about hundreds of years or less.(2) The) onset of the deglacial warming is not synchronous.The Guliya and Huguangyan records affected by the Indian and southeast monsoon indicate that the timing of the deglacial warming was at about 19kaB.P.In Antarctic region,the temperature increase was at about 18kaB.P.The Hulu cave,the DGKS9603 core,and the Weinan loess records show the warming at around 16kaB.P.It has long been known that the onset of the deglacial warming in the GRIP ice core was at about 14.5kaB.P.3) It seems that the deglacial warming is earlier in the south part of the Northern Hemisphere than in the north part and in Antarctic regions.Moreover,the deglacial warming manner is continuous in the south part,and abrupt in the north part.The climate change of Guliya is similar to that of Antarctic.Additionally,the Guliya and Huguangyan records show two-step warming in the deglaciation.