scholarly journals Loess record of the aerodynamic environment in the east Asia monsoon area since 60,000 years before present

Author(s):  
Xiaoguang Qin
2016 ◽  
Vol 12 (4) ◽  
pp. 871-881 ◽  
Author(s):  
Qing Wang ◽  
Houyun Zhou ◽  
Ke Cheng ◽  
Hong Chi ◽  
Chuan-Chou Shen ◽  
...  

Abstract. Stalagmite ky1, with a length of 75 mm and the upper part (from top to 42.769 mm depth) consisting of 678 laminae, was collected from Kaiyuan Cave in the coastal area of Shandong Peninsula, northern China, located in a warm temperate zone in the East Asia monsoon area. Based on high-precision dating with the U–230Th technique and continuous counting of laminae, the 1st and 678th laminae have been confirmed to be AD 1894 ± 20 and 1217 ± 20 from top to bottom, respectively. By the measurement of laminae thickness and δ18O ratios, we haved obtained the time series data of thickness of laminae and δ18O ratios from AD 1217 ± 20 to 1894 ± 20, analyzed the climatic–environmental meaning of variations in the thickness of laminae, which have a good correspondence with the cumulative departure curve of the drought–waterlog index in the historical period. The results show that, in the  ∼  678 years from AD 1217 ± 20 to 1894 ± 20, both the thickness of the laminae and the degree of fluctuation in the thickness of the laminae of stalagmite ky1 have obvious stages of variation and are completely synchronized with the contemporaneous intensity of the summer monsoons and precipitation as time changed. There is a negative correlation between the thickness of the laminae and the summer monsoon intensity and precipitation. There is a positive correlation between the degree of fluctuation in the thickness of the laminae and both the intensity of the summer monsoons and the precipitation. Therefore, for the Kaiyuan Cave in the coastal area of both the warm temperate zone and the East Asia monsoon area, the variations in the thickness of the laminae are not only related to the change in the climatic factors themselves but also related to the degree of climatic stability. In the coastal area belonging to the warm temperate zone and the East Asia monsoon area, the climate change between the LIA (Little Ice Age) and the MWP (Medieval Warm Period), in addition to less precipitation and low temperatures (a type of dry and cold climate), also shows an obviously decreasing trend in the degree of climatic stability.


2015 ◽  
Vol 11 (5) ◽  
pp. 4643-4668
Author(s):  
Q. Wang ◽  
H. Zhou ◽  
K. Cheng ◽  
H. Chi ◽  
C. Shen ◽  
...  

Abstract. Stalagmite ky1 was collected from Kaiyuan Cave in coastal areas of Shandong Peninsula, northern China, located at warm temperate zone and East Asia monsoon area, it was 75 mm in length, and the top 42.77 mm developed 678 laminae. Based on high precision dating with U-230Th technique, by continuous laminae counting, it can be confirmed that the 1st and 678th layer were 1217 and 1892 AD from top to bottom respectively. By the measurement of layer thickness and δ18O values, we got the layer thickness data and δ18O value time series data from 1217 to 1892 AD, analyzed the climatic significance of layer thickness variation on the basis of comparison. The result show that, in the 678 years from 1217 to 1892 AD, both the layer thickness variation of stalagmite ky1 and the variation of layer thickness fluctuation degree have obvious staged characteristic, and completely synchronized with the contemporaneous summer monsoon intensity/precipitation in time. Among, the thickness of layer and summer monsoon intensity/precipitation have negative correlation themselves. On the other hand, the layer thickness and the fluctuation degree of summer monsoon intensity/precipitation have positive correlation themselves. Therefore, Kaiyuan Cave, in the coastal area of warm temperate zone and East Asia monsoon area, the variation of layer thickness are relate to climatic factors variation themselves, and relate to climate stability degree in addition. For to achieve this, in the coastal area of warm temperate zone and East Asia monsoon area, the climate change between LIA and MWP, in addition to presented like less precipitation and low temperature that is to say dry and cold, also showed the climate stability degree obvious decreased.


2008 ◽  
Vol 8 (24) ◽  
pp. 7543-7555 ◽  
Author(s):  
Y. J. He ◽  
I. Uno ◽  
Z. F. Wang ◽  
P. Pochanart ◽  
J. Li ◽  
...  

Abstract. The impact of the East Asia monsoon on the seasonal behavior of O3 in the boundary layer of Eastern China and the west Pacific region was analyzed for 2004–2006 by means of full-year nested chemical transport model simulations and continuous observational data obtained from three inland mountain sites in central and eastern China and three oceanic sites in the west Pacific region. The basic common features of O3 seasonal behaviors over all the monitoring sites are the pre- and post-monsoon peaks with a summer trough. Such bimodal seasonal patterns of O3 are predominant over the region with strong summer monsoon penetration, and become weaker or even disappear outside the monsoon region. The seasonal/geographical distribution of the pre-defined monsoon index indicated that the East Asia summer monsoon is responsible for the bimodal seasonal O3 pattern, and also partly account for the differences in the O3 seasonal variations between the inland mountain and oceanic sites. Over the inland mountain sites, the O3 concentration increased gradually from the beginning of the year, reached a maximum in June, decreased rapidly to the summer valley in July or August, and then peaked in September or October, thereafter decreased gradually again. Over the oceanic sites, O3 abundance showed a similar increasing trend beginning in January, but then decreased gradually from the end of March, followed by a wide trough with the minimum in July and August and a small peak in October or November. A sensitivity analysis performed by setting China-emission to zero revealed that the chemically produced O3 from China-emission contributed substantially to the O3 abundance, particularly the pre- and post-monsoon O3 peaks, over China mainland. We found that China-emission contributed more than 40% to total boundary layer O3 during summertime (60–70% in July) and accounted for about 40 ppb of each peak value over the inland region if without considering the effect of the nonlinear chemical productions. In contrast, over the oceanic region in the high monsoon index zone, the contribution of China-emission to total boundary layer O3 was always less than 20% (<10 ppb), and less than 10% in summer.


2014 ◽  
Vol 35 (7) ◽  
pp. 1422-1433 ◽  
Author(s):  
Jehangir Ashraf Awan ◽  
Deg-Hyo Bae ◽  
Kyung-Joong Kim

2021 ◽  
Vol 32 (2) ◽  
pp. 159-169
Author(s):  
Fengnian Wang ◽  
Yuejun Si ◽  
Baosheng Li ◽  
Dongfeng Niu ◽  
Xiaohao Wen ◽  
...  

2008 ◽  
Vol 8 (4) ◽  
pp. 14927-14955 ◽  
Author(s):  
Y. J. He ◽  
I. Uno ◽  
Z. F. Wang ◽  
P. Pochanart ◽  
J. Li ◽  
...  

Abstract. The impact of the East Asia monsoon on the seasonal behavior of O3 in the boundary layer of Eastern China and the west Pacific region was analyzed for 2004–2006 by means of full-year nested chemical transport model simulations and continuous observational data obtained from three inland mountain sites in central and eastern China and three oceanic sites in the west Pacific region. The basic common features of O3 seasonal behaviors over all the monitoring sites are the pre- and post-monsoon peaks with a summer trough. Such bimodal seasonal patterns of O3 are predominant over the region with strong summer monsoon penetration, and become weaker or even disappear outside the monsoon region. The seasonal/geographical distribution of the pre-defined Monsoon Index indicated that the East Asia summer monsoon is responsible for the bimodal seasonal O3 pattern, and also partly account for the differences in the O3 seasonal variations between the inland mountain and oceanic sites. Over the inland mountain sites, the O3 concentration increased gradually from the beginning of the year, reached a maximum in June, decreased rapidly to a minimum in July or August, and then peaked in September or October, thereafter decreased gradually again. Over the oceanic sites, O3 abundance showed a similar increasing trend beginning in January, but then decreased gradually from the end of March, followed by a wide trough with the minimum in July and August and a small peak in October or November. A sensitivity analysis performed by setting China-emission to zero revealed that the chemically produced O3 from China-emission contributed more than 40% of total boundary layer O3 during summertime (60–70% in June) and accounted for about 40 ppb of each peak value over the inland region. In contrast, over the oceanic region in the high monsoon index zone, the contribution of China-emission to total O3 was always less than 20% (<10 ppb), and less than 10% in summer.


2018 ◽  
Vol 12 (02) ◽  
pp. 1
Author(s):  
Yazhen Jiang ◽  
Xiaoguang Jiang ◽  
Songcai You ◽  
Chen Ru

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