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

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.

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 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.

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

2011 ◽  
Vol 11 (4) ◽  
pp. 1671-1684 ◽  
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 relationship 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.

scholarly journals How Does the East Asian Summer Monsoon Behave in the Decaying Phase of El Niño during Different PDO Phases?

2014 ◽  
Vol 27 (7) ◽  
pp. 2682-2698 ◽  
Author(s):  
Juan Feng ◽  
Lin Wang ◽  
Wen Chen
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
East Asian Summer Monsoon ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
The Philippines ◽  
Central China ◽  
Rainfall Pattern ◽  
Asian Summer

Abstract Modulation of the Pacific decadal oscillation (PDO) on the behavior of the East Asian summer monsoon (EASM) in El Niño decaying years has been studied. When El Niño is in phase with the PDO (El Niño/high PDO), the low-level atmospheric anomalies are characterized by an anticyclone around the Philippines and a cyclone around Japan, inducing an anomalous tripolar rainfall pattern in China. In this case, the western Pacific subtropical high (WPSH) experiences a one-time slightly northward shift in July and then stays stationary from July to August. The corresponding anomalous tripolar rainfall pattern has weak subseasonal variations. When El Niño is out of phase with the PDO (El Niño/low PDO), however, the anomalous Philippines anticyclone has a much larger spatial domain, thereby causing an anomalous dipole rainfall pattern. Accordingly, WPSH experiences clearly two northward shifts. Therefore, the related dipole rainfall pattern has large subseasonal variations. One pronounced feature is that the positive rainfall anomalies shift northward from southern China in June to central China in July and finally to northern China in August. The different El Niño–EASM relationships are caused by the influences of PDO on the decaying speed of El Niño. During the high PDO phase, El Niño decays slowly and has a strong anchor in the north Indian Ocean warming, which is responsible for the anomalous EASM. Comparatively, during the low PDO phase, El Niño decays rapidly and La Niña develops in summer, which induces different EASM anomalies from that during the high PDO phase. Additionally, PDO changes El Niño behaviors mainly via modifying the background tropical winds.

Decoupling of the East Asian summer monsoon and Indian summer monsoon between 20 and 17 ka

2014 ◽  
Vol 82 (1) ◽  
pp. 146-153 ◽  
Author(s):  
Xiuyang Jiang ◽  
Yaoqi He ◽  
Chuan-Chou Shen ◽  
Shi-Yu Lee ◽  
Bang Yang ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Last Deglaciation ◽  
Oxygen Isotope Stage ◽  
Asian Summer

AbstractMarine Oxygen Isotope Stage (MIS) 2, with its profound environmental and climatic changes from before the last glacial maximum (LGM) to the last deglaciation, is an ideal period for understanding the evolution of the East Asian summer monsoon (EASM) and Indian summer monsoon (ISM), two Asian monsoon sub-systems. With 875 stable oxygen isotope ratios and 43 230Th dates from stalagmites in Sanxing Cave, southwestern China, we construct and interpret a new, replicated, Asian summer monsoon (ASM) record covering 30.9–9.7 ka with decadal resolution. δ18O records from this site and other reported Chinese caves display similar long-term orbitally dominated trends and synchronous millennial-scale strong and weak monsoonal events associated with climate changes in high northern latitudes. Interestingly, Sanxing δ18O and Arabian Sea records show a weakening ISM from 22 to 17 ka, while the Hulu and Qingtian records from East and Central China express a 3-ka intensifying EASM from 20 to 17 ka. This decoupling between EASM and ISM may be due to different sensitivities of the two ASM sub-systems in response to internal feedback mechanisms associated with the complex geographical or land-ocean configurations.

scholarly journals Assessing Future Changes in the East Asian Summer Monsoon Using CMIP3 Models: Results from the Best Model Ensemble

2013 ◽  
Vol 26 (5) ◽  
pp. 1807-1817 ◽  
Author(s):  
Kyong-Hwan Seo ◽  
Jung Ok
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Model Ensemble ◽  
Budget Analysis ◽  
Ensemble Mean ◽  
The Future ◽  
Asian Summer

Abstract Future changes in the East Asian summer monsoon (EASM) have been estimated from the six best-performing models in phase 3 of the Coupled Model Intercomparison Project (CMIP3) included in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC). The composite mean rainband over East Asia during the summer season exhibits the characteristic EASM front relatively well with slightly less precipitation over east–central China and the baiu front aligned more steeply in the latitudinal direction. An ensemble from the coupled models that poorly simulated the EASM is shown to degrade the overall results, giving rise to an underestimation of the projected increase rate in precipitation. In a quantitative estimate, the 22-member ensemble-mean precipitation for the period 2079–99 is anticipated to increase by only 5%–10%, which is half the increase in the corresponding mean precipitation from the good models (10%–20%). Moisture budget analysis demonstrates that the good-model ensemble mean is in a much closer correspondence with observations than the poor- or all-model ensemble mean, supporting the reliable selection of the best-performing models. An increase in the vertically integrated moisture flux convergence is attributed to the enhanced precipitation in the future climate. In particular, a significant increase in atmospheric water vapor because of a warmer SST over the western Pacific plays a more critical role in the enhanced precipitation than a change in monsoonal low-level circulation does. In contrast to the apparent meridional shift of the primary location of the future EASM front presented in previous studies, the current analysis shows a negligible amount of meridional movement.

scholarly journals Mechanisms for Spatially Inhomogeneous Changes in East Asian Summer Monsoon Precipitation during the Mid-Holocene

2020 ◽  
Vol 33 (8) ◽  
pp. 2945-2965 ◽  
Author(s):  
Na Wang ◽  
Dabang Jiang ◽  
Xianmei Lang
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Precipitation Pattern ◽  
West Central ◽  
Monsoonal Precipitation ◽  
Asian Summer ◽  
Precipitation Changes

AbstractThe East Asian summer monsoon (EASM) intensified during the early to mid-Holocene relative to the present primarily due to orbital forcing. However, on the regional scale, changes in the monsoonal precipitation exhibit considerable spatial disparity, and the underlying mechanisms remain unresolved. In this study, the dynamic processes responsible for the difference of the EASM precipitation between the mid-Holocene and preindustrial period are systematically examined using the CMIP5 multimodel simulations. The moisture budget diagnostic identifies vertical motion as the key factor determining the cross-like precipitation pattern in East Asia. Relative to the preindustrial period, the mid-Holocene anomalous ascending motion corresponds well with the excessive precipitation over northern and southern China, and vice versa for west-central China, the Korean peninsula, Japan, and its marginal seas. In the framework of the moist static energy budget, the increased insolation and the attendant intensification of land–sea thermal contrast give rise to anomalous ascending motions, while descending motions are fundamentally forced by the decreased latitudinal insolation gradient. In particular, thermodynamic changes, namely, the reduced pole–equator temperature and humidity gradients, account for the downward motions over the northwestern Pacific. Dynamic changes, namely, the weakened westerlies, play a leading role in suppressing updrafts in west-central China. This study highlights that the orbital-scale monsoonal precipitation changes are not solely determined by local radiative forcing as repeatedly emphasized before. The latitudinal uneven distribution of insolation is crucial to explain the spatial inhomogeneity in the EASM precipitation changes during the Holocene.

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