中文摘要：

在 Shennongjia 的 Dajiuhu 盆，在典型东方亚洲季风区域以内定位了，在它的中央区域保存亚高山带的水藓泥炭免职。最顶端 120 厘米泥炭最后 4000 年根据 AMS ¹⁴ 花粉集中标明日期的 C。α-cellulose 的碳同位素，从水藓泥炭提取了，提供大气的相对湿度的量的重建，基于 C ₃ 植物碳的转移功能，同位素的分别方程和藓苔类的植物光合作用公司 ₂ 吸收评价方程。δ ¹³ C， TOC 和 C/N 变化表明 Dajiuhu 区域经历了一个长期的趋势在 4000 1000 aBP 期间弄干，与发生在 3000 aBP 附近的主要转变。四个相对干燥事件被识别在 3400 3200， 3000 2600， 2200 2000 和 1600 1400 aBP，分别地相应于在许多全球记录记录的那些气候事件。三频率， 664 一， 302 一 and 277 一在 Dajiuhu 的大气的湿度围住被相关到太阳的活动的周期。在在 Dajiuhu 泥炭登记的这个时期期间变弱东亚夏天季风与印度季风的同步变弱一致。这个趋势可以被归因于北半球的夏天的渐渐的减少太阳的曝晒和热带会聚的地区(ITCZ ) 的因而向南方的迁居。

英文摘要：

The Dajiuhu Basin at Shennongjia, located within typical East Asian Monsoon region, preserves a sub-alpine sphagnum peat deposition in its central area. The topmost 120 cm of the peat covers the last 4000 years according to AMS ^14C dating of pollen concentration. Carbon isotope of a-cellulose, extracted from sphagnum peat, provides a quantitative reconstruction of atmospheric relative humidity, based on transfer functions of C3 plants carbon isotopic fractionation equation and the bryophyte photosynthesis CO2 absorption rate equation. δ^13C, TOC and C/N variations reveal that the Dajiuhu area has experienced a long-term tendency to dry during 4000-1000 aBP, with a major transition happening around 3000 aBP. Four relative dry events are identified at 3400-3200, 3000-2600, 2200-2000 and 1600-1400 aBP, respectively, corresponding to those climate events documented in many global records. Three periodicities, 664 a, 302 a and 277 a enclosed in the atmospheric humidity of Dajiuhu are correlated to the cycles of solar activities. The weakening of East Asia summer monsoon during this period registered in the Dajiuhu peat is consistent with the synchronous weakening of Indian Monsoon. This trend may be attributed to gradual decrease of Northern Hemispheric summer solar insolation and the consequently southward migration of Intertropical Convergent Zone （ITCZ）.