过去千年气候变化的数值模拟研究进展

在阐述千年气候变化研究意义的基础上,围绕着如何利用气候系统模式来对过去千年的气候变化进行归因模拟、以理解其中自然和人为因素的作用问题,总结和评述了国际上相关研究进展,进一步归纳了千年气候变化数值模拟中亟待解决的科学问题,重点包括千年气候演变中自然变率特征时段(即中世纪暖期和小冰期)与人类活动影响时段(即20世纪气候变暖)的气候差别,在中世纪暖期、小冰期和20世纪气候变暖这3个特征时段上,自然变化和人类活动影响的作用与机制比较、中国过去千年气候演变的模拟等,随后,扼要介绍了国家自然科学基金重大项目"中国地区树轮及千年气候变化研究"之课题"中国千年气候变化数值模拟与机理研究"的主要研究内容.     

Dating of Little Ice Age glacier fluctuations in the tropical Andes: Charquini glaciers,Bolivia, 16°S

Fluctuations of the Charquini glaciers (Cordillera Real, Bolivia) have been reconstructed for the Little Ice Age (LIA) from a set of 10 moraines extending below the present glacier termini. A lichenometric method using the Rhizocarpon geographicum was used to date the moraines and reconstruct the main glacier fluctuations over the period. The maximum glacier extent occurred in the second half of the 17th century, followed by nearly continuous retreat with three interruptions during the 18th and the 19th centuries, marked by stabilisation or minor advances. Results obtained in the Charquini area are first compared with other dating performed in the Peruvian Cordillera Blanca and then with the fluctuations of documented glaciers in the Northern Hemisphere. Glacier fluctuations along the tropical Andes (Bolivia and Peru) were in phase during the LIA and the solar forcing appears to be important during the period of glacier advance. Compared with the Northern Hemisphere mid-latitudes, the major advance observed on these glaciers during the first half of the 19th century is not present in the tropical Andes. This discrepancy may be due to regional scale climate variations. To cite this article: A. Rabatel et al., C. R. Geoscience 337 (2005).     

格陵兰冰芯氧同位素显示近千年气候变化的多尺度分析

用经验模态分解(EMD)方法对格陵兰冰盖GISP2冰芯古气候代用指标δ~ (18) O 序列进行分解, 结果表明: 格陵兰近10 ka来气候变化总趋势出现历时约490 a的中世纪暖期和历时约570 a的小冰期, 其间还存在次级的冷暖期变化;气候波动具有3 a、 6.5 a、 12 a、 24 a、 49 a、 96 a、 213 a、 468 a准周期, 既有NESO的因素, 也受制于太阳活动周期的影响. 第7, 第8内在模函数(IMF7, IMF8)波动振幅以及总体趋势分量res在1350A.D.出现明显的转型, 表明1350A.D.为中世纪暖期和小冰期的分界.