scholarly journals Variations in the East Asian summer monsoon over the past millennium and their links to the Tropic Pacific and North Atlantic oceans

2019 ◽  
Author(s):  
Fucai Duan ◽  
Zhenqiu Zhang ◽  
Yi Wang ◽  
Jianshun Chen ◽  
Zebo Liao ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Meridional Overturning Circulation ◽  
Central China ◽  
Ice Age ◽  
Future Global Warming ◽  
Asian Summer

Abstract. Variations of East Asian summer monsoon (EASM) during the last millennium could help enlighten the monsoonal response to future global warming. Here we present a precisely dated and highly resolved stalagmite δ18O record from the Yongxing Cave, central China. Our new record, combined with a previously published one from the same cave, indicates that the EASM has changed dramatically in association with the global temperature rising. In particular, our record shows that the EASM has intensified during the Medieval Climate Anomaly (MCA) and the Current Warm Period (CWP) but weakened during the Little Ice Age (LIA). We find that the EASM intensity is similar during the MCA and CWP periods in both northern and central China, but relatively stronger during the CWP in southern China. This discrepancy indicates a complicated regional response of the EASM to the anthropogenic forcing. The intensified and weakened EASM during the MCA and LIA matches well with the warm and cold phases of Northern Hemisphere surface air temperature, respectively. This EASM pattern also corresponds well with the rainfall over the tropical Indo-Pacific warm pool. Surprisingly, our record shows a strong association with the North Atlantic climate as well. The intensified (weakened) EASM correlates well with positive (negative) phases of North Atlantic Oscillation. In addition, our record links well with the strong (weak) Atlantic meridional overturning circulation during the MCA (LIA) period. All above-mentioned correlations indicate that the EASM tightly couples with oceanic processes in the tropical Pacific and North Atlantic oceans during the MCA and LIA.

scholarly journals Holocene variability of East Asian summer monsoon as viewed from the speleothem δ18O records in central China

2021 ◽  
Vol 558 ◽  
pp. 116758
Author(s):  
Yanjun Cai ◽  
Xing Cheng ◽  
Le Ma ◽  
Ruixue Mao ◽  
Sebastian F.M. Breitenbach ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Asian Summer

A late Holocene molecular hydrogen isotope record of the East Asian Summer Monsoon in Southwest Japan

2016 ◽  
Vol 86 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Els E. van Soelen ◽  
Naohiko Ohkouchi ◽  
Hisami Suga ◽  
Jaap S. Sinninghe Damsté ◽  
Gert-Jan Reichart
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Molecular Hydrogen ◽  
Hydrogen Isotope ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Ice Age ◽  
Southwest Japan ◽  
Asian Summer

AbstractPrecipitation in Japan is strongly affected by the East Asian monsoon system, resulting in wet summer conditions and relatively dry winter conditions. Few paleo-monsoon records exist from northeastern Asia, especially records showing decadal- to centennial-scale variability. Here we present a molecular hydrogen isotope (δD) record from Lake Kaiike, a small coastal lake in southwest Japan, to provide insight into monsoonal precipitation over the past two millennia. The δD record of friedelin, a terrestrial higher plant lipid, reveals three major shifts in precipitation: a decline from >-185‰ to <-190‰ at 1700 cal yr BP suggests a change to wetter conditions; values between -187.5‰ and -180‰ from 1480 to 800 cal yr BP indicate reduced precipitation; and a decline to below -195‰ after 800 cal yr BP reflects moist conditions during the Little Ice Age. These results highlight variability in the intensity of the East Asian Summer Monsoon occurring on decadal to centennial time scales. El Niño-like conditions are likely responsible for periods of high monsoon intensity, but comparison with other records in the region (northeast China and Japan) shows that contradicting patterns also exist, and so explaining these rainfall patterns is not straightforward.

scholarly journals Warm-season hydroclimate variability in Central China since 1866 AD and its relations with the East Asian Summer Monsoon: evidence from tree-ring earlywood width

2018 ◽  
Author(s):  
Yesi Zhao ◽  
Jiangfeng Shi ◽  
Shiyuan Shi ◽  
Xiaoqi Ma ◽  
Weijie Zhang ◽  
...  
Keyword(s):  
Tree Ring ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Qinling Mountains ◽  
Hydroclimate Variability ◽  
Asian Summer ◽  
Earlywood Width

Abstract. Historical hydroclimate records derived from tree-ring parameters are scarce in the core region of East Asian Summer Monsoon (EASM) in China, limiting our understanding of the inter-decadal hydroclimate variability of this region and its possible connections with the EASM. In this study, standard chronologies of total tree-ring width (TRW), earlywood width (EWW), and latewood width (LWW) were created using tree-ring samples of Pinus tabulaeformis in the eastern Qinling Mountains, Central China. The strongest growth-climate relationship was found between EWW and May–July self-calibrated Palmer Drought Severity Index (MJJ scPDSI). Therefore, a linear regression model, which explained 50.3 % of the variance in MJJ scPDSI (1951–2005), was developed to estimate the past MJJ scPDSI variations using EWW. The time series of MJJ scPDSI was extended back to the year 1866, and validated by independent hydroclimate series from nearby regions. Before the mid-1950s, the variations of MJJ scPDSI were in-phase with those of EASM intensity on decadal and longer timescales, suggesting that wet conditions would occur in the eastern Qinling Mountains when EASM was strengthened. Since the mid-1950s, however, the relationship has been out-of-phase. This phase change may be associated with an intensified dipole pattern of EASM precipitation.

Improvement of Multimodel Ensemble Seasonal Prediction Skills over East Asian Summer Monsoon Region Using a Climate Filter Concept

2013 ◽  
Vol 52 (5) ◽  
pp. 1127-1138 ◽  
Author(s):  
Doo Young Lee ◽  
Joong-Bae Ahn ◽  
Karumuri Ashok
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Seasonal Prediction ◽  
Multimodel Ensemble ◽  
Suitable Climate ◽  
Asian Summer ◽  
Summer Monsoon Region

AbstractThe authors propose the use of a “climate filter” concept to enhance prediction skill of a multimodel ensemble (MME) suite for the East Asian summer monsoon (EASM) precipitation and temperature at 850 hPa. The method envisages grading models on the basis of the degree of reproducibility of the association of EASM variability with a few relevant climate drivers with the respective model hindcasts for the period 1981–2003. The analysis identifies the previous winter Niño-3.4 and spring North Atlantic Oscillation indices as the most suitable climate drivers in designing a climate filter for evaluating models that replicate the observed teleconnections to EASM well. The results show that the hindcast skills of a new MME with the better-performing models are significantly higher than those from the nonperforming models or from an all-inclusive operational MME.

scholarly journals Timescale-dependence of the relationship between the East Asian summer monsoon strength and precipitation over eastern China in the last millennium

2017 ◽  
Author(s):  
Jian Shi ◽  
Qing Yan ◽  
Huijun Wang
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Ice Age ◽  
Last Millennium ◽  
Decadal Timescale ◽  
Asian Summer

Abstract. Precipitation/humidity proxies are widely used to reconstruct the historical East Asian summer monsoon (EASM) variation based on the assumption that summer precipitation over eastern China is closely and stably linked to the strength of EASM. However, whether the observed EASM-precipitation relationship (e.g., increased precipitation with a stronger EASM) was stable throughout the past time remains unclear. In this study, we used model outputs from the Paleoclimate Modelling Intercomparison Project Phase Ⅲ and Community Earth System Model to investigate the stability of the EASM-precipitation relationship over the last millennium on different timescales. The model results indicate that the EASM strength (defined as the regionally averaged meridional wind) enhanced in the Medieval Climate Anomaly (MCA; ~ 950–1250 A.D.), during which there was increased precipitation over eastern China, and weakened during the Little Ice Age (LIA; ~ 1500‒1800 A.D.), during which there was decreased precipitation, consistent with precipitation/humidity proxies. However, the simulated EASM-precipitation relationship is only stable on a centennial and longer timescale and is unstable on a multi-decadal timescale. The nonstationary multi-decadal EASM-precipitation relationship broadly exhibits a quasi-60-year period, which may be attributed to the internal variability of the climate system and have no significant correlation to external forcings. Our results have implications for understanding the discrepancy among various EASM proxies on a multi-decadal timescale and highlight the need to rethink reconstructed decadal EASM variations based on precipitation/humidity proxies.

scholarly journals Influence of the Summer NAO on the Spring-NAO-Based Predictability of the East Asian Summer Monsoon

2016 ◽  
Vol 55 (7) ◽  
pp. 1459-1476 ◽  
Author(s):  
Fei Zheng ◽  
Jianping Li ◽  
Yanjie Li ◽  
Sen Zhao ◽  
Difei Deng
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Dominant Mode ◽  
The North ◽  
Secondary Role ◽  
Asian Summer ◽  
The North Atlantic

AbstractThe dominant mode of atmospheric circulation over the North Atlantic region is the North Atlantic Oscillation (NAO). The boreal spring NAO may imprint its signal on contemporaneous sea surface temperature (SST), leading to a North Atlantic SST tripolar pattern (NAST). This pattern persists into the following summer and modulates the East Asian summer monsoon (EASM). Previous studies have shown that the summer NAST is caused mainly by the preceding spring NAO, whereas the contemporaneous summer NAO plays a secondary role. The results of this study illustrate that, even if the summer NAO plays a secondary role, it may also perturb summer SST anomalies caused by the spring NAO. There are two types of perturbation caused by the summer NAO. If the spring and summer NAO patterns have the same (opposite) polarities, the summer NAST tends to be enhanced (reduced) by the summer NAO, and the correlation between the spring NAO and EASM is usually stronger (weaker). In the former (latter) case, the spring-NAO-based prediction of the EASM tends to have better (limited) skill. These results indicate that it is important to consider the evolution of the NAO when forecasting the EASM, particular when there is a clear reversal in the polarity of the NAO, because it may impair the spring-NAO-based EASM prediction.

Dramatic weakening of the East Asian summer monsoon in northern China during the transition from the Medieval Warm Period to the Little Ice Age

Geology ◽  
2020 ◽  
Vol 48 (4) ◽  
pp. 307-312 ◽  
Author(s):  
Jianghu Lan ◽  
Hai Xu ◽  
Yunchao Lang ◽  
Keke Yu ◽  
Peng Zhou ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Little Ice Age ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Northern China ◽  
Medieval Warm Period ◽  
Warm Period ◽  
Ice Age ◽  
Asian Summer

Abstract Changes in the intensity of the East Asian summer monsoon (EASM) are critical for regulating the regional hydrology, ecology, and human civilization, especially in the vicinity of the summer monsoon limit (SML). However, the detailed spatial variations of the SML in mainland China over the past 2000 years are uncertain due to the lack of high-resolution paleoclimate archives. As a result, the accurate location of the SML during the transition from the Medieval Warm Period (MWP) to the Little Ice Age (LIA), as well as its impacts on ecology and society, are poorly understood. Here, we report a potential location of the SML during the late Holocene by combining data from a lake sedimentary record and a compilation of paleoclimate records from arid northern China. We find that EASM intensity was strong during the MWP and that the SML in arid northern China was roughly located along the Yinshan Mountains, Yabulai Mountains, and north of Lake Qinghai. EASM intensity dramatically weakened during the MWP-LIA transition, and the SML retreated southeastward significantly, which may have primarily but nonlinearly been a response to the reduction in solar irradiance and its associated changes in atmospheric circulation (e.g., El Niño–Southern Oscillation and Siberian High) and could have had profound impacts on hydrology, ecology, and human civilization across northern monsoonal Asia.

scholarly journals The 4.2 ka BP event: multi-proxy records from a closed lake in the northern margin of the East Asian summer monsoon

2018 ◽  
Vol 14 (10) ◽  
pp. 1417-1425 ◽  
Author(s):  
Jule Xiao ◽  
Shengrui Zhang ◽  
Jiawei Fan ◽  
Ruilin Wen ◽  
Dayou Zhai ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
Surface Waters ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Mean Annual Precipitation ◽  
Northern Margin ◽  
Proxy Records ◽  
Asian Summer

Abstract. The 4.2 ka BP event has been widely investigated since it was suggested to be a possible cause for the collapse of ancient civilizations. With the growth of proxy records for decades, however, both its nature and its spatial pattern have become controversial. Here we examined multi-proxy data of the grain-size distribution, ostracode assemblage, pollen assemblage, and the pollen-reconstructed mean annual precipitation from a sediment core at Hulun Lake in northeastern Inner Mongolia spanning the period between 5000 and 3000 cal. yr BP to identify the nature and the associated mechanism of the 4.2 ka BP event occurring in the monsoonal region of eastern Asia. Higher sand fraction contents, littoral ostracode abundances, and Chenopodiaceae pollen percentages together with lower mean annual precipitation reveal a significant dry event at the interval of 4210–3840 cal. yr BP that could be a regional manifestation of the 4.2 ka BP event in the northern margin of the East Asian summer monsoon (EASM). We suggest that the drought would be caused by a decline in the intensity of the EASM on millennial-to-centennial scales that could be physically related to persistent cooling of surface waters in the western tropical Pacific and the North Atlantic. The cooling of western tropical Pacific surface waters could reduce moisture production over the source area of the EASM, while the cooling of North Atlantic surface waters could suppress northward migrations of the EASM rain belt, both leading to a weakened EASM and thus decreased rainfall in the northern margin of the EASM.

scholarly journals Impact of the East Asian summer monsoon on long-term variations in the acidity of summer precipitation in Central China

2010 ◽  
Vol 10 (8) ◽  
pp. 19593-19630
Author(s):  
B. Z. Ge ◽  
Z. F. Wang ◽  
X. B. Xu ◽  
J. Tang ◽  
Y. J. He ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Ph Value ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Summer Precipitation ◽  
Central China ◽  
Asian Summer ◽  
Precipitation Acidity

Abstract. The acidity of precipitation has been observed at stations of the Acid Rain Monitoring Network run by the China Meteorological Administration (CMA-ARMN) since 1992. Previous studies have shown that different long-term trends exist in different regions but detailed analysis of the causes of these is lacking. In this paper, we analyze summertime precipitation acidity data from the CMA-ARMN during 1992–2006 using EOFs and show that the summertime pH in China had different trends before and after 2000. The most significant decrease of pH is found in Central China. To investigate the causes of this decrease of pH in summer, we explore the relationship between changes in the pH value, the East Asian summer monsoon index, rainfall data, and pollutants emissions. We find that the East Asian summer monsoon can significantly affect the acidity of summer precipitation in Central China. In strong monsoon years, the pH in Central China is about 0.33 lower than that in weak monsoon years. Chemical transport model simulations using fixed emissions indicate that about 65% of the pH value difference (i.e., 0.22) is related to the summer monsoon, and constitutes 18–36% of the observed pH change (0.6–1.2) in Central China during 1992–2006. Further studies reveal a teleconnection between the pH in Central China and the rainfall in the middle and lower reaches of the Yangtze River (MLYR), which can explain about 24% of the variance of pH in Central China. Simulations using an annually varying emission inventory show that at least 60% of the variation in precipitation acidity in Central China can be attributed to changes in pollutant emissions. Therefore, the increase in emissions of acidic species is the most important cause for the observed decrease of pH in Central China, and changes in meteorological factors, such as rainfall and other parameters related to the East Asian summer monsoon, play a less important but still significant role.

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