Clim. Past Discuss., 3, 1037–1061, 2007
www.clim-past-discuss.net/3/1037/2007/
© Author(s) 2007. This work is licensed
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Climate
of the Past
Discussions
Climate of the Past Discussions is the access reviewed discussion forum of Climate of the Past
Precipitation variations of Longxi,
northeast margin of Tibetan plateau since
AD 960 and its relationship with solar
activity
L. Tan1,3, Y. Cai1, L. Yi2,3, Z. An1, and L. Ai1,3
1State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment,
Chinese Academy of sciences, Xi’an, 710075, China
2Yantai Institute of Coastal Zone Research for Sustainable Development, Chinese Academy of
Sciences, Yantai, 264003, China
3Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
Received: 14 September 2007 – Accepted: 17 September 2007
– Published: 28 September 2007
Correspondence to: L. Tan (tanlch@ieecas.cn)
1037
Abstract
The precipitation variations of Longxi area, northeast margin of Tibetan plateau since AD 960 are reconstructed from Chinese historical documentary records. It shows that since AD 960, the precipitation of Longxi fluctuantly decreased to the lowest in the end stage of 17th century and 18th century. After this period, the precipitation gradually increased. Three short wet periods of Longxi in the last millennium were: from the end of 10th century to the early of 11th century, from the end of 12th century to the early of 13th century and the first half of 20th century. The precipitation variations of Longxi coincide well with variations of the Northern Hemisphere temperature and the atmospheric 14C concentration, the modeled solar output, the reconstructed total solar irradiance, which shows that solar activity may be the main driving force of precipitation variations of Longxi on multi-decadal to centennial scales in the last millennium.
Synchronous variations of Longxi precipitation and Northern Hemisphere temperature may be ascribed to the same control of solar activity. Solar activity controls remotion of the north edge of Asian summer monsoon by affecting Asia summer monsoon intensity, East Asian winter monsoon intensity and the locations of westerlies, thus further dominates precipitation variations of Longxi.
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6 Conclusions
5 Generally speaking, since AD 960, the climate of Longxi was fluctuating dry until to the driest in the period from the end stage of 17th century to 18th century. After this period the precipitation gradually increased in fluctuations. There were only three short wet periods: from the end of 10th century to the early of 11th century, from the end of 12th century to the early of 13th century and the first half of 20th century. 10 The precipitation variations of northeast margin of Tibetan plateau and northeast Tibetan plateau are consistent in the last millennium and are well correlated with average temperature variations in North Hemisphere on multi-decadal to centennial scales.
Good coherences among the precipitation variations of Longxi and variations of atmospheric 14C concentration, the modeled solar output, the reconstructed total solar irradiance show that solar activity may be the main driving force of precipitation variations of Longxi area on multi-decadal to centennial scales in the last millennium. The synchronous variations of Longxi precipitation and Northern Hemisphere temperature may be ascribed to the same control of solar activity. Solar activity controls the south to north motion of north edge of Asian summer monsoon by affecting Asia summer monsoon intensity, East Asian winter monsoon intensity and the locations of westerlies, thus further dominates precipitation variations of Longxi.
www.clim-past-discuss.net...
doi:10.1016/j.palaeo.2005.07.012
Copyright © 2005 Elsevier B.V. All rights reserved.
Temperature responses to quasi-100-yr solar variability during the past 6000 years based on δ18O of peat cellulose in Hongyuan, eastern Qinghai–Tibet plateau, China
Hai Xua, b, , , , Yetang Hongb, Qinghua Linb, Yongxuan Zhub, Bing Hongb and Hongbo Jiangb
aState Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, High-tech Zone, Xi'an, Shaanxi Province, PO Box 710075, China
bState Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
Received 28 October 2004; revised 17 July 2005; accepted 19 July 2005. Available online 22 August 2005.
Abstract
During the past 6000 years, the temperature variation trend inferred from δ18O of peat cellulose in a peat core from Hongyuan (eastern Qinghai–Tibet plateau, southwestern China) is similar to the atmospheric 14C concentration trend and the modeled solar output trend. The general trend of Hongyuan δ18O during the past millennium also coincides well with the atmospheric 14C concentration trend, the 10Be concentration trend in an ice core from the South Pole, the reconstructed total solar irradiance trend, as well as the modeled solar output trend. In addition, temperature events also correspond well to solar perturbations during the past 6000 years. Therefore, the driving force of Holocene temperature variations should be properly ascribed to solar activity. The spectrum analysis further illustrates that quasi-100-yr fluctuation of solar activity was probably responsible for temperature variations in northeast Qinghai–Tibet plateau during the past 6000 years.
Keywords: Peat; Oxygen isotopic composition; Temperature; Solar activity; Qinghai–Tibet plateau; China
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