摘要:
孢粉在古环境研究中具有重要价值,尤其是在重建古气候方面,既可以定性地恢复过去的植被类型变化,也能定量地重建气候变化规律,是古气候研究中最常用、较可靠和较成熟的环境代用指标.现代类比法是探讨表土孢粉与气候定量关系的方法之一,适用性较为广泛.本文利用青藏高原及其毗邻地区495个现代表土样点的孢粉谱,及现代气象站点器测资料,采用现代类比法得到气候参数的模拟值,并分析模拟值与气候参数观测值之间的关系.结果表明:相关性最高的气候因子是年均降水(r=0.894),其次为年均相对湿度(r=0.863)和年均蒸发量(r=0.801),最低的是干燥度(r=0.18).因此在重建古气候时降水的可信度较高,相对湿度和蒸发量也具有一定的可信度.并选用相关性较好的年均降水指标,分析其与11个孢粉类型之间的相关性,然后将相关性较高的孢粉组合与降水之间建立孢粉-气候函数模型,用以重建该地区过去气候变化.
Abstract:
The pollen has important value in palaeoevirormental research, especially in the field of paleoclimate reconstruction, because it can qualitatively restore paleovegetation type and reconstruct the climate rhythms. In addition, it is the most common, reliable and mature environmental substitute index in the paleoclimate research. Modern Analogue Technique has extensive applicability and is one of the methods for studying the relationship between surface pollen and climate. In this paper, the authors selected 495 surface pollen spectra in the Tibetan Plateau and its adjacent areas as well as the measurement data obtained by meteorological stations. Then, the authors calculated the Pearson's correlation coefficients between the observed values from the meteorological stations and the reconstructed values by using the Polygon software. The results indicate that the annual average precipitation had the highest correlation (r=0.894), followed by relative humidity (r=0.863) and annual average evaporation (r=0.801), with the lowest being aridity index (r=0.18). Therefore, the annual average precipitation has the higher credibility; and the relative humidity and the annual average evaporation have certain credibility in paleoclimate reconstruction. The authors calculated the relationship between the 11 pollen taxa and the annual average precipitation, and then chose the pollen taxas with better correlation coefficient to establish the pollen-climate model between the pollen assemblages and the annual average precipitation so as to reconstruct the paleoclimate change in this region.
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