EPR studies of Mn2+ in the Loess Plateau of central China: Implication for variation of the East Asia summer monsoon

1998 ◽  
Vol 43 (1) ◽  
pp. 72-75 ◽  
Author(s):  
Jun Chen ◽  
Junfeng Ji ◽  
Yuanxia Su ◽  
Huayu Lu
Keyword(s):  
East Asia ◽  
Loess Plateau ◽  
Summer Monsoon ◽  
Central China ◽  
The Loess Plateau ◽  
East Asia Summer Monsoon

scholarly journals Chronology of the Baxie Loess Profile and the History of Monsoon Climates in China Between 17,000 and 6000 Years BP

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 818-825 ◽  
Author(s):  
Weijian Zhou ◽  
Zhisheng An ◽  
Benhai Lin ◽  
Jule Xiao ◽  
Jinzhao Zhang ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Organic Content ◽  
Central China ◽  
Organic Component ◽  
Monsoon Circulation ◽  
The Loess Plateau ◽  
Asian Summer ◽  
Loess Profile

The valley of the Baxie River, situated in the western region of the Loess Plateau in central China, contains a loess profile 15 m thick, which can be considered representative of loess-paleosol sequences formed over the last 17 ka. Both thermoluminescence (TL) determinations on fine-grained sediment (4–11 μm) and 14C determinations on various organic fractions of paleosols from the profile have provided an extremely useful chronological framework for these sequences. These sequences indicate a weakened summer monsoon during the last glacial maximum followed by a strengthening of the summer monsoon, beginning ca. 13 ka cal bp. An abrupt change to a weakened summer monsoon regime lasted from ca. 10.9 to 10.2 ka cal bp. The Asian summer monsoon circulation, recording the Holocene optimum, then increased and lasted from ca. 10.2 to 6 ka cal bp. The organic component of samples taken down the profile has δ13C values ranging from −21 to −24‰ with respect to the PDB standard. The more positive δ13C values suggest that the proportion of C4-type plants in river valleys of the Loess Plateau increased as Asian summer monsoon influence weakened, and C3-type vegetation increased as the summer monsoon influence strengthened. Magnetic susceptibility and organic content were low during loess deposition, also reflecting weakening of summer monsoon. Two 14C determinations on the humin fraction of the organic component near the top of the lower paleosol and the base of the upper paleosol complex gave ages of 10.2 and 10.9 ka cal BP, respectively. These ages mark the beginning and termination of a brief event involving increased dust influx under weakened summer monsoon conditions.

Three-phase structure of the East Asia summer monsoon during Heinrich Stadial 4 recorded in Xianyun Cave, southeastern China

2021 ◽  
Vol 274 ◽  
pp. 107267
Author(s):  
Xin Zhang ◽  
Wanyin Qiu ◽  
Xiuyang Jiang ◽  
Hsun-Ming Hu ◽  
Haiyan Xiao ◽  
...  
Keyword(s):  
East Asia ◽  
Summer Monsoon ◽  
Phase Structure ◽  
Southeastern China ◽  
East Asia Summer Monsoon ◽  
Three Phase

scholarly journals The Evolution of the East Asia Summer Monsoon in June 1994 : Numerical Simulations

1998 ◽  
Vol 76 (5) ◽  
pp. 749-764 ◽  
Author(s):  
Kai-Hon Lau ◽  
An-Yu Wang ◽  
Ying-Hwa Kuo ◽  
Shou-Jun Chen ◽  
Jimy Dudhia
Keyword(s):  
East Asia ◽  
Numerical Simulations ◽  
Summer Monsoon ◽  
East Asia Summer Monsoon

scholarly journals Effects of climatic variability and human activity on runoff in the Loess Plateau of China

2013 ◽  
Vol 89 (02) ◽  
pp. 153-161 ◽  
Author(s):  
Yang Zhao ◽  
Xinxiao Yu
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Water Conservation ◽  
Human Activities ◽  
Climatic Variability ◽  
Land Use Changes ◽  
Annual Runoff ◽  
Central China ◽  
Vegetative Cover ◽  
The Loess Plateau

The Loess Plateau in north-central China has a long history of human activities. As a result of climate change, deforestation and sparse vegetative cover, the region suffers from water shortages and severe soil erosion, significantly influencing efforts for sustainable social development. In order to understand the impacts of climatic variability and human activities on runoff and other hydrological factors in this region, the Luoyugou catchment and its paired catchments (Qiaozidong and Qiaozixi) were selected. Statistical analysis indicated precipitation did not vary significantly whereas the annual runoff decreased from 1986 to 2008, with an abrupt change in 1994. Actual evapotranspiration (AET) increased slightly but not significantly. A comparison of runoff in the paired catchments showed land use changes reduced runoff by more than 38% under the same rainfall conditions. Human activities were the strongest contributor to changes in runoff and AET, at 67% and 90% respectively, while the remaining contributor was climate variation. The influence of various human activities on runoff is quite different, and soil-water conservation initiatives have a greater impact on runoff (about 41%). Thus, human activities were the primary reason for the reduction in runoff in the study catchment compared to climate. Greater emphasis should be given to afforestation and soil-water conservation measures.

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