| 1. |
- Han, Zhiyong, et al.
(författare)
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Extreme monsoon aridity episodes recorded in South China during Heinrich Events
- 2015
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 440, s. 467-474
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Tidskriftsartikel (refereegranskat)abstract
- Geological records of climate change since the last glaciation in South China, a core area of the East Asian monsoon, are key to understanding secular variation in the monsoon system. However, with the exception of the speleothems, records from this area with independent age control are few. We investigated aeolian sand deposition on a sand hill on the shore of Poyang Lake in South China and reconstructed the chronological sequence of aeolian deposition using Optically Stimulated Luminescence (OSL) dating. Without exception, all aeolian sediments were deposited within seven periods that generally match the timing of Heinrich events and other cold periods in Greenland. We argue that aeolian sand accumulation in this region is most likely forced by extreme aridity driven by weakening of the summer monsoon, while the characteristics of this deposition are influenced by winter monsoon intensity. The monsoon shifts revealed here suggest a possible link between North Atlantic cooling and summer monsoon strength in South China, and support the intensities of cooling phases recorded in Greenland ice cores.
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| 2. |
- Jiang, Mengyao, et al.
(författare)
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Beach ridges of Dali Lake in Inner Mongolia reveal precipitation variation during the Holocene
- 2020
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 35:5, s. 716-725
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Tidskriftsartikel (refereegranskat)abstract
- Variability in East Asian summer monsoon precipitation during the Holocene remains of debate. In this study, we use a closed lake with well‐dated lake beach ridges located on the margin of the East Asian summer monsoon, a region highly sensitive to monsoon precipitation changes, to obtain a temporal sequence of water volume in North China. The elevation of each beach ridge calibrated to the modern lake level was surveyed. Optically stimulated luminescence dating of undisturbed sediments of beach ridges was performed. The lake area and water volume corresponding to each beach ridge were calculated using a digital elevation model. This study reveals relatively reduced monsoon precipitation from ~12 to 7 ka interrupted by strengthening of the monsoon circulation to a maximum from ~7 to ~5 ka and followed by greatly reduced monsoon intensity until the present day. These results demonstrate that changes in the East Asian summer monsoon precipitation may not be directly driven by global temperature or atmospheric CO2 content. Rather, we suggest that variation in the the monsoon margin precipitation is probably mainly driven by ice volume and subordinately by the summer solar insolation difference between mid‐latitude land and low‐latitude ocean.
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