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以洛川黄土剖面中 >30 μm的粗颗粒含量作为东亚冬季风强度代用指标 ,根据模式并结合绝对年代控制点建立了较精确的独立的时间标尺。对该时间序列进行了小波变换分析和频谱分析。结果表明 ,最近 10 2 4ka以来东亚冬季风变化在 12 8ka和 6 4ka时间尺度上幅度最大 ,更短或更长的时间尺度冬季风变化幅度减小。东亚冬季风变化的 10 0 ka和 2 1ka等周期可能受地球轨道运动驱动的太阳辐射量变化控制 ,而 5 7ka和 33ka等周期的驱动机制还有待于进一步查明。
Taking the coarse grain content of> 30 μm in the loess section of Luochuan as the proxy index of winter monsoon intensity in East Asia, a more accurate and independent time scale was established according to the model and the control point of absolute age. The time series were analyzed by wavelet transform and spectrum analysis. The results show that the winter monsoon change in East Asia has been the largest at 12 8ka and 6 4 ka since the last 10 2 4 ka, and decreases at the shorter or longer time scale. The 10 0 ka and 21 ka periods of the East Asian winter monsoon change may be controlled by changes in solar radiation driven by the Earth orbital motion. The driving mechanism for periods such as 57 ka and 33 ka remains to be further identified.