引用本文: | 谢宇,刘粤峰,程彩玉,周梦涛,彭小桃,程珂,周厚云.2021.太阳活动和ENSO控制南岭东部有效降水变化[J].地球环境学报,12(2):137-145 |
| XIE Yu, LIU Yuefeng, CHENG Caiyu, ZHOU Mengtao, PENG Xiaotao, CHENG Ke, ZHOU Houyun.2021.Solar activity and ENSO controlled variation of effective precipitation in the eastern Nanling Mountains[J].Journal of Earth Environment,12(2):137-145 |
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摘要: |
在我国东南地区,器测时代之前的气候环境变化是否与ENSO活动有关还未见报道。本文在210Pb定年基础上,重建了南岭东部过去150 a(分辨率1.86 a)的石笋δ 18O记录。对比器测指标,发现该石笋δ 18O记录与当地有效降水变化密切相关,并以此重建了南岭东部地区过去150 a有效降水变化历史。南岭东部有效降水变化与ENSO活动密切相关,El Niño态对应有效降水增加和石笋δ 18O变轻,La Niña态对应有效降水减少和石笋δ 18O变重。有效降水变化长期趋势受到太阳活动控制,太阳活动减弱时南岭东部有效降水增加,反之亦然。ENSO和太阳活动变化引起的雨带位置和西北太平洋副热带高压变化主导了南岭东部有效降水的变化。本研究结果表明,石笋可能成为研究这一地区ENSO影响下年际—年代际尺度上降水变化的有力工具。 |
关键词: 石笋 稳定氧同位素 有效降水 ENSO 太阳活动 华南 |
DOI:10.7515/JEE202026 |
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基金项目:国家自然科学基金项目(4127121,41473093);广东省自然科学基金重点项目(9251064004000001) |
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Solar activity and ENSO controlled variation of effective precipitation in the eastern Nanling Mountains |
XIE Yu, LIU Yuefeng, CHENG Caiyu, ZHOU Mengtao, PENG Xiaotao, CHENG Ke, ZHOU Houyun
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School of Geography, South China Normal University, Guangzhou 510631, China
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Abstract: |
Background, aim, and scope ENSO could influence the Northwest Pacific Subtropical High (NPSH) and location of monsoon rain belt, which in turn resulted in differential variations of precipitation in eastern China. This was confirmed by modern observations which showed that El Niño led to more precipitation in South China and less precipitation in North China and La Niña led to an opposite picture. However, it’s still not clear whether the ENSO-rainfall association existed in South China prior to the modern observations. A stalagmite (LFD-1), which was collected from the eastern Nanling Mountains in South China, was used to explore the possible correlation between ENSO activities and precipitation variations in South China during the last 150 years. Materials and methods The stalagmite LFD-1 is 156 mm in length and was collected from Tiger Cave in the eastern Nanling Mountains. Thirteen sub-samples were drilled for 210Pb dating. Sub-samples for stable oxygen and carbon isotope (δ 18O-δ 13C) analysis were obtained by micro-milling along the growth axis of LFD-1 with a 0.25 mm interval and one from every two sub-sample was picked out for δ 18O-δ 13C analysis. The δ 18O-δ 13C isotopes were determined with a Thermo-Fisher MAT 253 mass spectrometer. Results The 210Pb dating results indicated that the top 40 mm of LFD-1 had an average growth rate of (0.27±0.02) mm·a−1, suggesting that the top 40 mm of LFD-1 developed during the last 150 a. During the last 150 a, the δ 18O record had a highest value of −5.03‰ (at a depth of 13.4 mm), a lowest value of −8.30‰ (at a depth of 0.88 mm) and an average of −6.34‰. Significant inter-annual to decadal variations could be observed in the LFD-1 δ 18O record. Discussion The LFD-1 δ 18O record displayed high similarity to the effective precipitation (EP) and temperature records at a nearby meteorological station at Chenzhou during the last 60 a. Changes in temperature could explain only a small part of the variation of the δ 18O record. The δ 18O variations were attributed largely to EP variations with lighter δ 18O corresponding to higher EP and vice versa. Both the δ 18O record and EP showed similar trends to an ENSO proxy, the sea surface temperature (SST) over the Niño 3 district. Positive SST anomalies (El Niño-like mode) corresponded to more EP at the eastern Nanling Mountains and lower δ 18O values in LFD-1 and vice versa. The long-term trend of the δ 18O record paralleled roughly to the total solar irradiance. Shifts of the monsoon rain belt controlled by ENSO activities and solar irradiance were suggested to be responsible for changes in the EP over the eastern Nanling Mountains and the δ 18O record of LFD-1. Stronger ENSO activities and weaker solar irradiance contributed a southward shift of the monsoon rain belt, resulting in more rainfall in South China and vice versa. Conclusions (1) The LFD-1 δ 18O record was an appropriate proxy for EP variations in the eastern Nanling Mountains. (2) The variation of EP in the eastern Nanling Mountains is highly correlated to ENSO and solar activities. On inter-annual to decadal time scales, higher (lower) EP and lighter (heavier) δ 18O corresponded to stronger ENSO activities and vice versa. The long-term trend of EP variation was also controlled by solar irradiance with weaker (stronger) activities leading to higher (lower) EP in the Nanling Mountains and vice versa. (3) ENSO and solar activities modulated the EP in the Nanling Mountains by influencing the NPSH and location of the monsoon rain belt in eastern China. Recommendations and perspectives The speleothems in Southeastern China may be suitable archives for investigation of ENSO controlled rainfall variations in this region, a very important economic zone of China. The speleothem δ 18O records from this region may also provide key information for explanation of the speleothem δ 18O records from monsoonal China. However, more precisely dated speleothem δ 18O records covering longer periods are needed. |
Key words: speleothem δ18O effective precipitation ENSO solar activity South China |