Quantifying the palaeoclimates of Qinghai–Tibetan Plateau is vital for understanding the uplift history of plateau and the evolution of Asian monsoon since Cenozoic. Recently, the Coexistence Approach (CA) has been employed to reconstruct the palaeoelevation and palaeoclimate of the plateau by several studies. However, the application of CA in mountainous areas and the realism of climate reconstructions via this method are seldom discussed, although the complexity of reconstructions is speculated. Here we reevaluated the realism of climate reconstruction using the CA with modern pollen samples from the Qinghai–Tibetan Plateau, and try to explore the possible factors influencing the precipitation and temperature reconstructions by CA. We suggest that the long-distance transport pollen as a result of the Asian summer monsoon potentially significantly affects the reconstructions both for precipitation and temperature. The precipitation complexly interacting with snowmelt and permafrost thaw leads to the discrepancy between the reconstructed precipitation and the real value. The response temperature for blossoming of dwarfed plants on the plateau is mostly likely higher than the air temperature (usually measured at 1.5 m above ground) due to energy flux or morphological adaptation of inflorescences during the growing season, causing the distortion of temperature reconstructions. Precipitation reconstruction is notoriously difficult as the establishers of CA have already suggested, but reconstructing the low temperatures may be even more challenging on Qinghai–Tibetan Plateau. Though all of the explorations in current paper are in a qualitative way, it offers an inspiration of how appropriately interpret the disagreements between CA results and the observations, and of how to obtain a reasonable reconstruction of palaeoclimate of the plateau.

中文翻译：

---

青藏高原共存法气候重建的复杂性

量化青藏高原古气候对于理解青藏高原的隆升历史和新生代以来亚洲季风的演变具有重要意义。最近，多项研究采用共存法（CA）重建了高原的古海拔和古气候。然而，尽管推测了重建的复杂性，但很少讨论 CA 在山区的应用以及通过这种方法重建气候的真实性。在这里，我们用青藏高原现代花粉样本重新评估了使用 CA 重建气候的真实性，并尝试探索影响 CA 降水和温度重建的可能因素。我们认为，亚洲夏季风造成的长距离运输花粉可能会显着影响降水和温度的重建。降水与融雪和多年冻土融化的复杂相互作用导致重建的降水与真实值之间存在差异。由于能量通量或花序在生长季节的形态适应性，高原矮化植物开花的响应温度很可能高于气温（通常在离地1.5 m处测量），导致温度重建失真。正如 CA 的建立者已经提出的那样，降水重建是出了名的困难，但在青藏高原重建低温可能更具挑战性。