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选择位于西风影响区的天山东段巴里坤湖湖泊岩芯样品,对沉积物粒度组分进行经验正交函数(EOF)分解,并探讨各分量的环境意义。结果显示,EOF1组分与沉积物粒度小于2μm组分相关系数达0.64以上,并与代表区域有效湿度的碳酸盐氧同位素指标有很好的对应关系,故将EOF1解译为区域有效湿度的替代指标。EOF2组分与粒级为45～138μm的颗粒相关系数大于0.65,且该粒级范围与区域降尘概率曲线的粗颗粒部分相似,可能指示区域风沙强度。通过EOF分解所得到的两个组分显示中全新世为有效湿度较低、风沙活动较强的时段,这一结果与发生在以蒙古高原北部为中心的区域中全新世干旱事件有较好的对应关系。同时,西伯利亚高压的加强所导致的西风环流和冬季风的增强为风沙活动提供了较好的动力基础,因此亚洲内陆干旱区的干旱化和风动力条件的加强很可能是导致该区域中全新世风沙活动增强的主导因素。
The core samples of Barkhun Lake and lake in the east Tianshan section of the Westerly wind affected area were selected to conduct empirical orthogonal function (EOF) decomposition of the sediment grain size components. The environmental significance of each component was also discussed. The results showed that the correlation coefficient between EOF1 and sediment particle size of less than 2μm was above 0.64, which was in good correspondence with the carbonate oxygen isotope index of effective moisture in representative area. Therefore, EOF1 was interpreted as the effective moisture content Alternative indicators. The correlation coefficient between EOF2 component and grain size of 45 ~ 138μm is greater than 0.65, and the range of grain size is similar to the coarse grain part of the probability curve of regional dustfall, which may indicate the sandstorm strength of the region. The two components obtained by EOF decomposition show that the Middle Holocene is a period with low effective humidity and strong sand blown activity. This result is in good agreement with the Holocene arid event occurring in the northern part of the Mongolia Plateau Corresponding relationship. At the same time, the enhanced westerly circulation and intensification of the winter monsoon caused by the intensification of the high pressure in Siberia provide a good dynamic foundation for wind-blown sand activities. Therefore, the aridification and aero-dynamic conditions in the inland arid in Asia are most likely to lead to the Holocene Aeolian activity increased the dominant factor.