过去2000年中国东南地区气温与降水的集成重建与分析

Integrated Reconstruction and Analysis of Temperature and Precipitation Changes in Southeastern China during the Last 2000 Years

筛选和利用中国东南地区(大致范围为105oE以东、30oN以南) 16个站点的多种气候代用指标序列,重建了东南地区过去2 000年以来的气温与降水变化过程,并探讨了其可能的影响机制。研究发现,东南地区气温集成序列与其他学者重建的中国温度序列、北半球温度序列等均具有较好的可比性,一些百年尺度的典型特征气候时期,如黑暗时代冷期、中世纪暖期、近代小冰期以及20世纪现代暖期等均有显著的体现;降水集成序列显示东南地区在过去2 000年中干湿阶段性变化较为明显,特别是在中世纪暖期时降水整体上较为偏多,而在小冰期的前半段降水偏少、后半段降水偏多。总体来看,近2 000年来我国东南地区的气温与降水变化经历了较为多样的水热组合过程。值得指出地是,东南地区降水集成序列与已有的中国北方地区多条降水重建序列相互间可比性较弱,反映了中国东部季风区由南到北降水变化及其影响机制具有很大的区域性差异。分析认为,大尺度海—气相互作用、火山活动以及太阳辐射量变化等对我国东南地区过去2 000年的气候环境变化具有显著影响。

Studies of historical climate and environment changes in the eastern monsoonal region of China have made great progress in recent years. However, progressively studies indicate that the processes of climate and environment changes during the last 2000 years differed greatly in different regions. This is especially the case among studies based only on single-site records, possibly because of different materials, proxy indicators, dating accuracy, etc. Therefore, it is necessary to conduct comprehensive and integrated analyses of regional climate and environment changes at larger spatial scales. Here, multiple climate proxy records selected from 16 sites in southeastern China(i. e., approximately east of 105° E and south of 30° N) were used to synthesize and reconstruct the temperature and precipitation changes over the past 2000 years, and the possible forcing mechanisms behind these changes were explored. The results indicate that the integrated temperature sequence in the study region is quite comparable to the reconstructions for the entirety of China, eastern China, and the Northern Hemisphere. Several typical characteristic climate periods on centennial timescales, such as the Dark Age Cold Period, the Medieval Warm Period, the Little Ice Age, and the modern warm period of the 20 th century,were well revealed in the present reconstruction. The integrated precipitation sequence shows that the dry and wet phases in southeastern China have changed significantly during the past 2000 years. Specifically, precipitation was relatively higher during the Medieval Warm Period, but it was relatively lower during the Little Ice Age(i.e.,less precipitation occurred in the former part of the Little Ice Age and more precipitation occurred during the latter part). In general, the synthesized temperature and precipitation changes in southeastern China had relatively diverse hydrothermal combinations during the last 2000 years. However, it is noteworthy that the integrated precipitation sequence in southeastern China is weakly comparable to the sequence in northern China, reflecting great regional differences in historical precipitation changes. Thus, the forcing mechanisms might differ greatly from south to north in the monsoonal region of eastern China. Furthermore, the results suggest that large-scale atmosphere – ocean interactions, volcanic activities, and changes in solar radiation could have had significant effects on the climate and environment changes in southeastern China during the last 2000 years.