20世纪气候变暖的归因是当前全球共同关注的焦点之一,而解决这一问题的途径之一是对过去千年的气候变化历史进行精确重建。简要回顾过去千年气候重建的研究进展,重点关注古气候空间重建方法方面的最新进展,并将目前古气候空间重建方法划分为3类,即综合-比例法(Composite Plus Scale,CPS)、气候场重建法(Cli mate Field Reconstruction,CFR)以及状态空间模型(State-space Model)法,同时指出了这些方法的优缺点以及可能的解决途径。
Ephedraceae has been applied largely as a drought indicator to reconstruct Cenozoic paleoenvironment and paleoclimate. However, temperature indication of Ephedraceae has been largely ignored. Here, we provide a record of Ephedraceae percentage spanning from the Early Eocene to Middle Miocene （52-17 Myr B.P.） in the Xining Basin, northeastem Tibetan Plateau. This record is comparable to a compiled Cenozoic Ephedraceae record from five other basins in northwestern China. Both records show Ephedraceae percentages were high during the Early Eocene, and decreased gradually from the Middle Eocene to Late Oligocene, then maintained a stable level since the Late Oligocene. By comparing these two Ephedraceae records with the marine oxygen isotope record, we discuss the variation of Ephedmceae percentage in Middle Cenozoic in response to global temperature change. Ephedraceae percentage was high in the Early Paleogene, associated with subtropical or tropical vegetation types in a global greenhouse climate, and decreased in Early Oligocene, associated with global cooling, suggesting that Ephedmceae is warm-tolerant during the Paleogene. The low Ephedraceae percentages in the Late Oligocene and Miocene were uncoupled with global warming, which may imply that Ephedraceae began to adapt to a eurythermic climate in the inland desert environment of westem China. Such adaptation may be a response to the high topography of the Tibetan Plateau.
