坝上草原全新世以来孢粉组合与古环境研究
发布时间：2018-11-19 14:56
【摘要】：孢粉是研究古气候、古环境演变的有效代用指标,建立表土孢粉组合与气候之间的关系模型是定量恢复古气候的基础。而模型建立的关键是在现有气象资料(温度、降水等)基础上,利用插值方法获得采样点对应的气象数据。本研究首先对坝上地区气象数据采用不同的插值方法进行比较,研究表明,在坝上地区,协同克里金法是最佳的气温降水数据插值方法。运用协同克里金法根据经纬度赋值给表土花粉,建立表土孢粉与气温降水模型。在建立年代序列的基础上,对坝上察汗淖尔剖面344 cm的湖泊沉积样品进行孢粉、粒度分析,定量重建坝上全新世以来的古气候古环境演变特征。其中,重点分析全新世阶段,其余时间段则合并为一个阶段进行分析。在11.73 ka B.P.~45.66 ka B.P.阶段,年均温4.80℃,年降水量为344.96 mm。在7.68 ka B.P.~11.73ka B.P.阶段,年均温和年降水量均略有上升。在6.04 ka B.P.~7.68 ka B.P阶段,年均温为4.84℃,年降水量为347.81mm。在4.12 ka B.P.~6.04 ka B.P阶段,年均温略有上升。在3.81 ka B.P.~4.16 ka B.P阶段,年均温和年降水量均继续上升。在3.54 ka B.P.~3.81 ka B.P阶段,年均温达到最高值,年降水量也达到最高值。年均温度为5.08℃,年降水量为354.28 mm。此后2.80 ka B.P.~3.54 ka B.P.阶段,年均温和年均降水量均呈现波动下降的趋势。2.21 ka B.P.~2.73 ka B.P.阶段,年均温持续下降且年均降水量下降。从2.21 ka B.P.至今,年均温度为4.79℃,年均降水量为348.15 mm。分析表明坝上地区全新世以来的气候总体表现为温度升高及降水增多,在全新世中期,气温最高和降水量最多。全新世晚期以来,该区气候再次有温度降低降水量减小然后又增大的变化趋势,这与其他地区全新世以来气候特征总体一致,但具有地区气候演变差异的特征,其研究结果有助于了解该地区尤其北方农牧交错带典型气候特征,进而为该地区环境政策的制定提供基础资料及理论依据。
[Abstract]:Sporopollen is an effective substitute index for the study of paleoclimate and paleoenvironmental evolution, and the establishment of a relationship model between palynological assemblage and climate is the basis for quantitative restoration of paleoclimate. On the basis of the existing meteorological data (temperature, precipitation, etc.), the key to model establishment is to obtain the meteorological data corresponding to the sampling points by using interpolation method. Firstly, different interpolation methods are used to compare the meteorological data in Bashang area. The results show that the synergetic Kriging method is the best interpolation method for temperature and precipitation data in Bashang area. A model of surface soil pollen and temperature precipitation was established by using the method of synergetic Kriging to assign pollen to the surface soil according to the longitude and latitude values. Based on the time series, the paleoclimate paleoenvironmental evolution characteristics since the Holocene were quantitatively reconstructed by pollen and particle size analysis of the lake sediment samples of 344 cm in Cnnao section, Bashang. The Holocene stage is mainly analyzed, and the other time periods are merged into one stage. At 11.73 ka B.P.~45.66 ka B.P. The annual mean temperature is 4.80 鈩，
本文编号：2342684
[Abstract]:Sporopollen is an effective substitute index for the study of paleoclimate and paleoenvironmental evolution, and the establishment of a relationship model between palynological assemblage and climate is the basis for quantitative restoration of paleoclimate. On the basis of the existing meteorological data (temperature, precipitation, etc.), the key to model establishment is to obtain the meteorological data corresponding to the sampling points by using interpolation method. Firstly, different interpolation methods are used to compare the meteorological data in Bashang area. The results show that the synergetic Kriging method is the best interpolation method for temperature and precipitation data in Bashang area. A model of surface soil pollen and temperature precipitation was established by using the method of synergetic Kriging to assign pollen to the surface soil according to the longitude and latitude values. Based on the time series, the paleoclimate paleoenvironmental evolution characteristics since the Holocene were quantitatively reconstructed by pollen and particle size analysis of the lake sediment samples of 344 cm in Cnnao section, Bashang. The Holocene stage is mainly analyzed, and the other time periods are merged into one stage. At 11.73 ka B.P.~45.66 ka B.P. The annual mean temperature is 4.80 鈩，
本文编号：2342684
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