黄土高原西缘3万年以来古气候变化——磁化率代用气候曲线的多尺度分析

The Multiscale Analysis of Paleoclimate Change of the West Edge of the Loess Plateau Since 30,000 Years

黄土高原西缘红咀寺剖面气候代用曲线的小波多尺度分析(Multiresolutionanalysis),较好地表达了不同周期(时间尺度)的古气候演化特点。分析结果表明:在30-10kaBP的次冰盛期内,(1)约有56个百年尺度的气候波动,15个千年尺度的气候循环,3个冰阶—间冰阶周期;(2)在小波分解后的千年级尺度气候曲线上,暖事件更为突出,有3个突出的峰(Denekamp,?(未命名),(BΦlling);(3)新仙女木事件仅反映在百年尺度的气候曲线上,在较长周期的曲线上不明显;(4)在百年尺度的气候曲线中,末次冰盛期气候波动频繁,其中18-28kaBP是频率波动最大的阶段,但随着周期尺度的加大,气候的波动频率逐渐趋于均匀。

It has been proved that Multi scale (Multi resolution) analysis of wavelet transforms in an important method to study the changing cycles of the Quaternary period climate on different time scales. In the west edge of the loess plateau, the wavelet analysis of magnetic capbability climate substitutute curve of HongZuiShi section shows that 1) ther are about 56 climatic fluctuations of hundred- year- scale, 15 climatic cycles of thousand- year- scale and 3 glacial staircases- interglacial staircase periods during the last glacial maximumin (30- 10kaBP); 2) in the thousand- year- scale climatic curve decomposed with wavelet, warm events are more outstanding, having 3 outstanding peaks (Denekamp,?,BΦlling); 3) Younger Dryas Only has reflection in the hundred- year- scale climatic curve, it is not evident in the curve of long period; 4) in the hundred- year- scale climatic curve, the last glacial maximum fluctuation as frequently and 18- 28kaBP was the stage in which the frequency fluctuation e was the largest. But the climatic fluctuation frequency tends to be regular with the increase of the period scale.