高分辨率湖泊-三角洲相沉积记录的18世纪中叶以来鄱阳湖地区气候演化特征

该文基于鄱阳湖地区高分辨率(0.7 a/1.5 cm)湖泊-三角洲沉积记录的地球化学特征,重建了该区域18世纪中叶以来的气候演化序列.分析表明:鄱阳湖地区河湖相小于20 μm的沉积物硅铝率(n(SiO₂)/n(Al₂O₃))、铷锶比(Rb/Sr)敏感地响应了区域气温变化,指示区域气候自18世纪中叶以来经历了暖-冷-暖3个阶段,其中的偏冷阶段由1790—1820年、1853—1905年的2个强冷时段和1820—1853年的弱冷时段组成,在长江中下游地区和华南地区的记录中普遍反映了这种气候演化阶段; 20世纪以来该区域气候逐渐变暖.功率谱分析显示:区域气温存在85 a、33 a、11 a和2～5 a的震荡周期,这与太阳辐射、太阳黑子活动和ENSO的周期一致; 该区域气候1790—1820年和1853—1905年的强冷时段对应了太阳辐射的低值期和火山活动的活跃期,这表明长江中下游地区的气候演化受火山活动、太阳辐射强度、太阳黑子活动及低纬海气作用的共同影响.

The Climate Change Recorded by High-Resolution Delta and Lake Sedimentary in the Poyang Lake Area since Mid-18th Century

Based on the geochemical characteristics of high-resolution delta and lake sediments(ca.0.7 a/1.5 cm)in the Poyang Lake region,proxy records about climate and environment change is developed over the last 240 years.The results show that in Poyang Lake area,SA(n(SiO₂)/n(Al₂O₃))and Rb/Sr(less than 20 μm)of sediment respond to regional temperature change and indicate that the climate in the region has been warm-cold-warm for 240 years.This research confirms that all through the 19th century interval is a cold period indeed,which is divided into three substages that are the two strong cold ones at 1790—1820 A.D.,1853—1905A.D. respectively,and the weak cold one between them.This kind of climate change characteristic is quite common in the climate reconstruction record of the middle and lower reaches of the Yangtze River and the South China region.Since the 20th century,the climate in the region has gradually warmed.Power spectrum analysis indicates that there exists significantly 85 a,33 a,11 a and 2—5 a periodic oscillations,closely relevant to solar irradiation,sunspot activity and the western pacific subtropical high.The cold phase of the of volcanic activity.The above results indicate that the evolution of climate and environment in the middle and lower reaches of the Yangtze River basin is influenced by volcanic activity,solar rregional climate also corresponds to the low value period of solar radiation and the active period adiation intensity,sunspot activity and sea and western pacific subtropical high.