福建梅花山泥炭腐殖化度记录的过去千年气候变化

全球变暖背景下频发的极端气候事件, 严重影响了经济社会可持续发展。研究过去人类活动背景下的气候变化特征可为预测气候变化趋势、制定应对策略提供历史借鉴。本研究选取福建梅花山国家级自然保护区山间泥炭岩芯(长度238cm)119个沉积物进行腐殖化度分析, 结合粒度和烧失量记录, 重建近千年来福建地区高分辨率气候历史。研究结果显示, 在东亚季风区的低纬亚高山山间盆地, 泥炭沉积物腐殖化度越高, 指示气候越冷干; 腐殖化度越低, 指示气候越暖湿。梅花山泥炭腐殖化度在980~1529A.D.呈现低值(均值8.4%), 指示中世纪暖期较强的东亚季风和暖湿气候; 1529~1926A.D.呈显著高值(均值24.8%), 指示明清小冰期较弱的季风和冷干气候; 1926A.D.以来波动下降(均值22.8%), 对应了现代暖期。梅花山泥炭腐殖化度记录与区域沉积记录显示出对东亚季风的同步响应。研究结果记录了小冰期的第二次和第三次冷期, 分别为1589~1757A.D.和1842~1926A.D.。梅花山泥炭腐殖化度记录的近千年气候变化可能受太阳辐射、热带辐合带和厄尔尼诺/南方涛动等的共同驱动。

The climate change over the past 1000 years by humification records of a peat core from Meihua Mountain in Fujian Province

Climate extremes are increasing induced by global warming, which threaten the sustainability of economic and social development. The study of past climate changes under the background of increasing human activities can provide suggestions for forecast and response of future climate change. In this study, we obtained a peat core(25°20.94'N, 116°48.92'E; altitude 1450m)in a subalpine basin from Meihua Mountain National Nature Reserve in Fujian Province, Southeast China. The length of the core is 238cm and 119 sediment samples of the peat core were used to measure the grain size, loss on ignition and humification to reconstruct the high-resolution climate variations over the past 1000 years in Fujian Province. The results show that higher(lower)content of humification from peat sediments indicates colder and drier(warmer and wetter)climate in the low-latitude subalpine basin of the East Asian summer monsoon area. The low content of peat humification(with the average value of 8.4 %)from 980A.D. to 1529A.D. indicated that the climate was warm and humid with stronger East Asian summer monsoon during the Medieval Warm Period, whereas significantly high content humification(with the average value of 24.8 %)from 1529A.D. to 1926A.D. indicated a cold and dry climate with weaker East Asian summer monsoon during the Little Ice Age of Ming and Qing Dynasties. The humification decreased(with the average value of 22.8 %)with fluctuations since 1926A.D., reflecting the Current Warm Period. The humification records from Meihua Mountain and nearby sedimentary records indicate the synchronous response of regional sedimentary records to the East Asian summer monsoon. Two cold periods were recorded in the peat core during the Little Ice Age: 1589~1757A.D. and 1842~1926A.D., which correspond to the second and third cold periods of the Little Ice Age in China. The climate change recorded by humification from Meihua Mountain over the past 1000 years may be driven by the variation of solar radiation, intertropical convergence zone and El Nino/Southern Oscillation.