张伟宏^1,,
陈仕涛²,
汪永进²,
赵侃²,
邵庆丰²,
王天阳¹,
朱丽东¹
1. 浙江师范大学地理与环境科学学院, 浙江 金华 321004
2. 南京师范大学地理科学学院, 江苏 南京 210023

基金项目: 国家自然科学基金项目（批准号：41602350、41602181和41572340）资助


详细信息

作者简介: 张伟宏, 女, 32岁, 讲师, 第四纪地质学专业, E-mail:zhangwh@zjnu.cn

中图分类号: P597⁺.1;P534.63⁺2;P532

收稿日期:2018-11-20
修回日期:2019-02-15
刊出日期:2019-05-30

Rapid change in the East Asian summer monsoon: Stalagmite records in Hubei, China

Zhang Weihong^1,,
Chen Shitao²,
Wang Yongjin²,
Zhao Kan²,
Shao Qingfeng²,
Wang Tianyang¹,
Zhu Lidong¹
1. College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, Zhejiang
2. College of Geography Science, Nanjing Normal University, Nanjing 210023, Jiangsu


MSC: P597⁺.1;P534.63⁺2;P532

--> Received Date: 20 November 2018
Revised Date: 15 February 2019
Publish Date: 30 May 2019


摘要
摘要:研究小冰期的结构特征及动力机理有助于理解全球增暖和极端气候事件的原因。基于湖北永兴洞总长为120 mm的YX275石笋7个高精度²³⁰Th年龄和120个氧同位素数据，重建了1361~1955 A.D.时段分辨率达5 a的东亚夏季风降水变化序列。该石笋δ¹⁸O值在-7.8 ‰~-9.3 ‰范围内波动，长期趋势呈现出先缓慢增大后减小的变化特征，整体呈下凹形态。该记录与中国季风区北部和南部石笋记录变化大体一致，指示小冰期发生时东亚夏季风水循环发生减弱变化。在百年-数十年尺度上，YX275石笋记录的小冰期内5次显著季风降水减弱事件与南部贵州董哥洞、织金洞石笋记录变化一致，但不同于北方大鱼洞、九仙洞、黄爷洞和万象洞石笋记录的5次小幅度季风旋回特征，表明小冰期时中国南北部夏季风降水在短时间尺度上可能存在着区域差异。该记录与太阳总辐照度记录和北半球温度记录变化一致，表明太阳总辐照度和北半球温度变化对东亚夏季风水文变化有重要驱动作用。
关键词: 石笋/
高分辨率/
小冰期/
东亚季风/
区域差异

Abstract:It is of great importance to know the structure and forcing of the Little Ice Age(LIA) for deciphering the causes of global warming and extreme events over the modern times. Here a high-resolution stalagmite record form Yongxing Cave(31°35'N, 111°14'E; 800 m above sea level) is provided to characterize the hydro-climatic during the LIA.
The cave is located in Xiema Town, Mt. Shennongjia, in Hubei Province, Central China. The cave is about 500 m in length, and overlain by about 50 m of Silurian limestone. The vegetation above the cave is dense, primarily covered with perennial woody plants and shrub herbaceous plants. The cave has a narrow entrance, thus the cave relative humidity is close to 100%. The site is dominated by East Asian monsoon. The annual atmospheric temperature is approximately 8℃, and annual precipitation ranges from 1500~2000 mm. More than 50% of the annual precipitation falls in the summer seasons from June to August. Stalagmite YX275 is 120 mm in length, and 35~55 mm in diameter. When halved and polished, the central growth axis shows translucent calcite and the margin displays yellowish white throughout the whole sample.
The subsamples, weighing about 30 μg and 60 mg respectively, were obtained along the growth axis for the stable isotope and U/Th date analyses. The measurements for U/Th dating were performed by inductively coupled plasma mass spectrometry(ICP-MS) on a Finnigan-MAT Element at the Isotope Laboratory of Nanjing Normal University and the δ¹⁸O data were produced by the MAT-253 mass spectrometer fitted with a Kiel Carbonate Device in that Isotope Laboratory. Precision of δ¹⁸O is 0.06 ‰, at the 1-sigma level.
We construct the time-series of the East Asian summer monsoon precipitation by using a total of 120 δ¹⁸O data and 7 ²³⁰Th dates. The chronology for the time-series was established using the MOD-AGE model, and it showed that the stalagmite grew from 1361~1955 A.D., spanning the LIA. The YX275 δ¹⁸O record ranges from -7.8 ‰ to -9.3 ‰, with an average value of -8.5 ‰, and displays a long-term hollow shape. The higher δ¹⁸O values occurred over the LIA, suggesting less summer monsoon precipitation. The less monsoon precipitation inferred from the YX275 record is supported by a large number of cave records from northern and southern China. These cave records consistently indicate that the weak monsoon precipitation during the LIA. Within the LIA, monsoonal fluctuations are recognized on the centennial and multi-decadal scale. A total of five weak precipitation episodes are detected, which are correlated with the Dongge and Zhijin records in Southern China. However, these monsoon precipitation decreases are not mirrored in the Dayu, Jiuxian, Huangye and Wanxiang records in Northern China. The northern records are marked by five low-amplitude monsoon cycles across the LIA. The contrast between the northern and southern records indicates the existence of the inconsistent monsoon precipitation behaviors between different regions on the centennial and multi-decadal scale. Nevertheless, the Yongxing cave record generally shows a similar shape to the total solar irradiance and Northern Hemisphere temperature. These similarities indicate an influence of the solar irradiance and northern temperature on the hydrological cycle in East Asian region during the LIA.
Key words:stalagmite/
high resolution/
LIA/
East Asian Monsoon precipitation/
regional difference



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