西北干旱区湖泊沉积记录反映的全新世气候波动周期性变化  

HOLOCENE CLIMATIC PERIODICITIES RECORDED FROM LAKE SEDIMENTS IN THE ARID-SEMIARID AREAS OF NORTHWESTERN CHINA

作　　者：靳立亚[1] 陈发虎[1] 朱艳[1] 

机构地区：[1]兰州大学中德干旱环境联合研究中心西部环境教育部重点实验室,兰州730000

出　　处：《海洋地质与第四纪地质》2004年第2期101-108,共8页Marine Geology & Quaternary Geology

基　　金：国家自然科学杰出青年基金项目(40125001);国家自然科学面上基金项目(40275022)

摘　　要：采用多窗谱分析方法研究了夏季风边缘区———甘肃民勤盆地石羊河流域湖泊沉积物所记录的全新世以来气候波动的周期性。结果表明,该区域的气候变化存在明显的1553、1190、686、617、504、314、180及131a等主要周期。1553a主周期变化所对应的明显干湿期有6—7次。其他百年尺度的周期变化在早中全新世波动幅度较大,到中、晚全新世其波幅逐渐减小。其中准1500a的周期波动在整个全新世石羊河流域气候变化中都有反映,而500～700a的周期波动在中全新世气候变化过程中起重要作用。Two paleoclimatic proxy records of lake sediments from Sanjiaocheng (SJC) section (at 39°00′38″N, 103°20′25″E) in the Shiyang River drainage are used to analyze the Holocene climatic periodicities. One is the series of the total organic carbon (TOC) and the other is the pollen concentration. The amounts of the TOC of lacustrine sediment normally indicate the preservation of the organic matter and the preliminary productivity of paleolake, and the study of the carbon isotope of the SJC section has shown that the high-TOC values match well with the rich aquatic plant content and the increase in depth of the paleolake water, mainly due to the increase of the rainfall and the strong summer monsoon. The pollen concentration of the lake sediments from SJC section generally indicates effective humidity and vegetation state in the Shiyang River drainage. The Multi-Taper Method of Spectrum Analysis (MTM) is a powerful tool for time series analysis that can identify intermittent oscillation spells, in short, noise time series and it was applied to analyze the series of the TOC and pollen concentration. The result shows there are obvious periodicities of 1 553,1 506,1 190, 686, 617,504,314,180 and 131 years both in the TOC and pollen concentration sequences, in which the 1553-year periodicity corresponds to 6～7 times of dry-wet intervals during the Holocene. The centennial-scale periodicities of about 500～700 are important to the oscillation of the climate during the mid-Holocene in the arid regions of northwestern China.

关 键 词：湖泊沉积 全新世 气候变化 波动 多窗谱分析 

分 类 号：P467[天文地球—大气科学及气象学]