The sensitivity analysis of reconstructing ancient temperature by different circumstantial evidence and methods

Reconstructing the ancient temperature is the focus of attention of PAGES. Due to the difference between the type of circumstantial evidence and method of reconstructing ancient temperature, there exists certain difference between the records of reconstructing ancient temperature. The temperature of types of circumstantial evidence such as spore and pollen, phytolith, comprehensive evidence, oxygen isotope and glacier-periglacial decrease in turn at the same time and spot. The temperatures of spore and pollen and phytolith are closest to each other, and those of comprehensive evidence and oxygen isotope are relatively close to each other. This indicates that the temperature numerical value of reconstructing spore and pollen is relatively high; the evidence of glacier-periglacial is relatively high, which mainly shows the temperature of growing season of plants and winter half year (cold period); while the comprehensive evidence and oxygen isotope may be close to the actual temperature. According to the reconstruction method, the wholly new world temperature record reconstructed by transfer function analysis is generally higher than that by natural geographical factor indication method; while the range of variation of the temperature record reconstructed by natural geographical factor indication method is higher (especially the cold events), which indicates that the temperature record reconstructed by factor indication method is more sensitive to the extreme event of hundred years.