scholarly journals Stalagmite-inferred abrupt climate change of Asian Summer Monsoon at MIS 5a/4 transition

2017 ◽  
Author(s):  
Xiuyang Jiang ◽  
Yaoqi He ◽  
Xiaoyan Wang ◽  
Jinguo Dong ◽  
Zhizhong Li ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Ice Core ◽  
Precise Determination ◽  
Monsoon Period ◽  
Atmospheric Teleconnection ◽  
The North ◽  
Strong Resemblance ◽  
Asian Summer

Abstract. The Greenland Interstadial 21 (GIS 21), one of the longest warm events during the last glacial, occurred in conjunction with the transition from marine isotope stages (MIS) 5a to 4. Precise determination of the timing and duration of this event can improve our understanding of hydroclimatic connection between low and high latitudes over this MIS boundary. Facilitated by a robust chronology with closely spaced U-Th ages, replicated sub-decadal-resolved δ18O records of two stalagmites from Sanxing Cave, Southwest China, express Asian Summer Monsoon (ASM) history from 79.0 ± 0.2 to 75.7 ± 0.2 thousand years before present (kyr BP, before AD 1950) to reveal detailed structure of MIS 5a/4 transition and Chinese Interstadial (CIS) 21. The composited Sanxing record is characterized with three centennial-scale strong monsoon peaks and a 700-yr-long weak monsoon period within the CIS 21 rebound-type event, concurrent with its counterpart of Greenland Interstadial 21 (GIS 21). This strong resemblance suggests a rapid atmospheric teleconnection between the North Atlantic and the ASM regions. The transition at the termination of the Chinese Interstadial (CIS) 21 is determined to be from 77.0 ± 0.2 to 76.6 ± 0.2 kyr BP with a mid-point at 76.8 ± 0.2 kyr BP, which is 0.5–1.0 kyr younger than the correspondent of the end of GIS 21 on GICC05modelext and AICC2012 timescales. Given its high accuracy, our Sanxing Cave chronology can become one of the potential references for chronological refinement for ice-core records.

scholarly journals Assessing Future Changes in the East Asian Summer Monsoon Using CMIP5 Coupled Models

2013 ◽  
Vol 26 (19) ◽  
pp. 7662-7675 ◽  
Author(s):  
Kyong-Hwan Seo ◽  
Jung Ok ◽  
Jun-Hyeok Son ◽  
Dong-Hyun Cha
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Moisture Flux ◽  
Moisture Convergence ◽  
Cmip5 Models ◽  
Moisture Flux Convergence ◽  
The North ◽  
Asian Summer

Abstract Future changes in the East Asian summer monsoon (EASM) are estimated from historical and Representative Concentration Pathway 6.0 (RCP6) experiments of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The historical runs show that, like the CMIP3 models, the CMIP5 models produce slightly smaller precipitation. A moisture budget analysis illustrates that this precipitation deficit is due to an underestimation in evaporation and ensuing moisture flux convergence. Of the two components of the moisture flux convergence (i.e., moisture convergence and horizontal moist advection), moisture convergence associated with mass convergence is underestimated to a greater degree. Precipitation is anticipated to increase by 10%–15% toward the end of the twenty-first century over the major monsoonal front region. A statistically significant increase is predicted to occur mostly over the Baiu region and to the north and northeast of the Korean Peninsula. This increase is attributed to an increase in evaporation and moist flux convergence (with enhanced moisture convergence contributing the most) induced by the northwestward strengthening of the North Pacific subtropical high (NPSH), a characteristic feature of the future EASM that occurred in CMIP5 simulations. Along the northern and northwestern flank of the strengthened NPSH, intensified southerly or southwesterly winds lead to the increase in moist convergence, enhancing precipitation over these areas. However, future precipitation over the East China Sea is projected to decrease. In the EASM domain, a local mechanism prevails, with increased moisture and moisture convergence leading to a greater increase in moist static energy in the lower troposphere than in the upper troposphere, reducing tropospheric stability.

scholarly journals Understanding the Interdecadal Variability of East Asian Summer Monsoon Precipitation: Joint Influence of Three Oceanic Signals

2018 ◽  
Vol 31 (14) ◽  
pp. 5485-5506 ◽  
Author(s):  
Zhiqi Zhang ◽  
Xuguang Sun ◽  
Xiu-Qun Yang
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
Asian Summer Monsoon ◽  
Wave Train ◽  
Eastern China ◽  
Monsoon Precipitation ◽  
The North ◽  
Joint Influence ◽  
Asian Summer ◽  
Precipitation Anomalies

Abstract East Asian summer monsoon precipitation (EASMP) features complicated interdecadal variability with multiple time periods and spatial patterns. Using century-long datasets of HadISST, CRU precipitation, and the ECMWF twentieth-century reanalysis (ERA-20C), this study examines the joint influence of three oceanic interdecadal signals [i.e., Pacific decadal oscillation (PDO), Atlantic multidecadal oscillation (AMO), and Indian Ocean Basin mode (IOBM)] on the EASMP, which, however, is found not to be simply a linear combination of their individual effects. When PDO and AMO are out of phase, the same-sign SST anomalies occur in the North Pacific and North Atlantic, and a zonally orientated teleconnection wave train appears across the Eurasian mid-to-high latitudes, propagating from the North Atlantic to northern East Asia along the Asian westerly jet waveguide. Correspondingly, the interdecadal precipitation anomalies are characterized by a meridional tripole mode over eastern China. When PDO and AMO are in phase, with opposite sign SST anomalies in the North Pacific and North Atlantic, the sandwich pattern of anomalous stationary Rossby wavenumber tends to reduce the effect of the waveguide in the eastern Mediterranean region, and the teleconnection wave train from the North Atlantic travels only to western central Asia along a great circle route, causing Indian summer monsoon precipitation (ISMP) anomalies. The ISMP anomalies, in turn, interact with the teleconnection wave train induced by the PDO and AMO, leading to a meridional dipole mode of interdecadal precipitation anomalies over eastern China. Through the impact on the ISMP, the IOBM exerts significantly linear modulation on the combined impacts of PDO and AMO, especially over northern East Asia.

scholarly journals Climatic Effects of China Large-Scale Urbanization on East Asian Summer Monsoon under Different Phases of Pacific Decadal Oscillation

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 90
Author(s):  
Yongxiao Liang ◽  
Pengfeng Xiao
Keyword(s):  
Summer Monsoon ◽  
Pacific Decadal Oscillation ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Vertical Motion ◽  
Positive Phase ◽  
The North ◽  
Asian Summer

The effects of urbanization over eastern China on the East Asian summer monsoon (EASM) under different sea surface temperature background are compared using a Community Atmosphere Model (CAM5.1). Experiments of urbanization investigated by comparing two climate simulations with and without urban land cover under both positive and negative phases of Pacific Decadal Oscillation (PDO) show the spatial distribution of precipitation with ‘southern flood and northern drought’ and weakening status of EASM. The climate effect of urbanization in eastern China is significantly different from north to south. Anomalous vertical ascending motion due to the role of urbanization in the south of 30° N have induced an increase in convective available potential energy (CAPE) and precipitation increase over southern China. At the same time, the downward vertical motion occurs in the north of 30° N which cause warming over northern China. Due to the anti-cyclonic anomalies in the upper and lower layers of the north, the monsoon circulation is weakened which can reduce the precipitation. However, urbanization impact under various phases of PDO show different effect. In the 1956–1970 urbanization experiments of negative PDO phase, the downward vertical motion and anti-cyclonic anomalies in the north of 30° N are also weaker than that of positive phase of PDO in 1982–1996. In terms of this situation, the urbanization experiments of negative phase of PDO reveal that the range of the warming area over the north of 40° N is small, and the warming intensity is weak, but the precipitation change is more obvious compared with the background of positive phase of PDO.

scholarly journals Association of the pre-monsoon thermal field over north India and the western Tibetan Plateau with summer monsoon rainfall over India

2015 ◽  
Vol 33 (8) ◽  
pp. 1051-1058 ◽  
Author(s):  
S. D. Bansod ◽  
S. Fadnavis ◽  
S. P. Ghanekar
Keyword(s):  
Tibetan Plateau ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Summer Monsoon Rainfall ◽  
North India ◽  
Monsoon Region ◽  
The North ◽  
Western Tibetan Plateau ◽  
Asian Summer ◽  
Summer Monsoon Region

Abstract. In this paper, interannual variability of tropospheric air temperatures over the Asian summer monsoon region during the pre-monsoon months is examined in relation to Indian summer monsoon rainfall (ISMR; June to September total rainfall). For this purpose, monthly grid-point temperatures in the entire troposphere over the Asian summer monsoon region and ISMR data for the period 1949–2012 have been used. Spatial correlation patterns are investigated between the temperature field in the lower tropospheric levels during May over the Asian summer monsoon region and ISMR. The results indicate a strong and significant northwest–southeast dipole structure in the spatial correlations over the Indian region, with highly significant positive (negative) correlations over the regions of north India and the western Tibetan Plateau region – region R1 (north Bay of Bengal: region R2). The observed dipole is seen significantly up to a level of 850 hPa and eventually disappears at 700 hPa. Thermal indices evaluated at 850 hPa level, based on average air temperatures over the north India and western Tibetan Plateau region (TI1) and the north Bay of Bengal region (TI2) during May, show a strong, significant relationship with the ISMR. The results are found to be consistent and robust, especially in the case of TI1 during the period of analysis. A physical mechanism for the relationship between these indices and ISMR is proposed. Finally the composite annual cycle of tropospheric air temperature over R1 during flood/drought years of ISMR is examined. The study brings out the importance of the TI1 in the prediction of flood/drought conditions over the Indian subcontinent.

Radiation and aerosol measurements over the Tibetan Plateau during the Asian summer monsoon period

2020 ◽  
Vol 11 (9) ◽  
pp. 1543-1551
Author(s):  
Jinqiang Zhang ◽  
Xiangao Xia ◽  
Hongrong Shi ◽  
Xuemei Zong ◽  
Jun Li
Keyword(s):  
Tibetan Plateau ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
The Tibetan Plateau ◽  
Monsoon Period ◽  
Asian Summer

Decoupling of stalagmite-derived Asian summer monsoon records from North Atlantic temperature change during marine oxygen isotope stage 5d

2008 ◽  
Vol 70 (2) ◽  
pp. 315-321 ◽  
Author(s):  
Houyun Zhou ◽  
Jianxin Zhao ◽  
Pingzhong Zhang ◽  
Chuan-Chou Shen ◽  
Baoquan Chi ◽  
...  
Keyword(s):  
East Asia ◽  
Summer Monsoon ◽  
North Atlantic ◽  
Asian Summer Monsoon ◽  
North Atlantic Region ◽  
Atlantic Region ◽  
Oxygen Isotope Stage ◽  
The North ◽  
Asian Summer ◽  
The North Atlantic

AbstractThe Asian monsoon is an important component of the global climate system. Seasonal variations in wind, rainfall, and temperature associated with the Asian monsoon systems affect a vast expanse of tropical and subtropical Asia. Speleothem-derived summer monsoon variation in East Asia was previously found to be closely associated with millennial-scale change in temperature in the North Atlantic region between 75 and 10 ka. New evidence recovered from East Asia, however, suggests that the teleconnection between summer monsoon in East Asia and temperature change in the North Atlantic region may have significantly reduced during 120 to ~ 110 ka, a period directly after the full last interglaciation and corresponding roughly to marine oxygen isotope stage 5d. This reduction may be due to the low ice volume in the North Hemisphere at that time, which makes the millennial-scale change in temperature in the North Atlantic region less effective in influencing the Asian summer monsoon. This is important for investigating the mechanisms controlling the Asian summer monsoon and the paleoclimatic teleconnection between East Asia and the North Atlantic region, and for predicting monsoon-associated precipitation in East Asia under a global-warming trend.

A southern and northern control on speleothem-based Asian summer monsoon variability during MIS 4

2019 ◽  
Vol 92 (3) ◽  
pp. 738-753
Author(s):  
Dianbing Liu ◽  
Shushuang Liu ◽  
Yifan Fang
Keyword(s):  
Summer Monsoon ◽  
North Atlantic ◽  
Southern China ◽  
Asian Summer Monsoon ◽  
Phase Correlation ◽  
The North ◽  
Asian Summer ◽  
The North Atlantic ◽  
Freshwater Inputs

AbstractA 20-year-resolution speleothem δ18O record from southern China reveals a detailed Asian summer monsoon (ASM) history between 73.6 and 62.3 ka. ASM changes during Interstadial 19 and late MIS 4 matched Greenland temperature variations but were antiphased with Antarctic temperatures. However, long-term strengthening of the ASM in early MIS 4 agrees well with the gradual Antarctic warming, when Greenland remained in a stable cold state. More specifically, the ASM was less variable during peak interstadials in contrast to striking instabilities during stadials. These observations suggest that the factors dominating ASM variability change through time. During early MIS 4, negligible freshwater perturbations occurred in the North Atlantic, and sea-surface temperatures in the low- to midlatitude Pacific Ocean reached the modern level. Thus, an expansion of the Intertropical Convergence Zone (ITCZ) was likely important for the long-term ASM rise. In late MIS 4, the antiphase correlation between ASM and Antarctic temperature could be attributed to freshwater inputs into the North Atlantic and a southerly positioned ITCZ. Consequently, meridional ITCZ shifts, although within a limited latitudinal band, would result in an antiphase relationship between interhemispheric climate changes. Otherwise, an in-phase correlation could be expected if the centroid of ITCZ is stable along the equator.

Eastward Eddy Shedding of the Asian Summer Monsoon Anticyclone

2021 ◽  
Author(s):  
Xinyue Wang ◽  
William Randel ◽  
Yutian Wu
Keyword(s):  
North America ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Lower Troposphere ◽  
Western Pacific ◽  
The North ◽  
The Pacific ◽  
Asian Summer ◽  
The Western Pacific ◽  
Eddy Shedding

<p>Eastward eddy shedding of the Asian summer monsoon (ASM) anticyclone has a large impact on the chemical composition of the upper troposphere and lower stratosphere (UTLS) over the western Pacific. Here we investigate the dynamical mechanism of eastward eddy shedding in July and August using 41 years of the ERA5 6-hourly reanalysis data. We perform composite analyses of meteorological variables focusing on the eastward eddy shedding events with the presence of anticyclonic centers falling between 135<sup>•</sup>-140<sup>•</sup>E. The composited outgoing longwave radiation anomalies suggest enhanced convection near the Philippines Sea and the East China Sea one week beforehand. In the tropopause level, we see evident eastward propagating geopotential and meridional wind anomalies from the North Atlantic jet exit toward the western Pacific embedded along the extratropical westerly jet during day -10 to day 0. In the lower troposphere, we find that the geopotential anomalies aligned meridionally from the east Asian coast to the North Pacific to the northern North America during day -7 to day 0. The wave-activity flux is evaluated to identify the origin and propagation of the energy of the Rossby wave–like perturbation. In the UTLS we find a strong southeastward-pointing flux along 40<sup>•</sup>-50<sup>•</sup>N, resembling the Silk Road pattern. While in the lower troposphere, we also see a northeastward-pointing flux originating from tropical Philippine Sea across Japan to North America, resembling the Pacific-Japan pattern. Additional analysis is needed to study the relationship between the Silk Road pattern and the Pacific-Japan pattern.</p>

scholarly journals The Eurasian ice sheet reinforces the East Asian summer monsoon during the interglacial 500 000 years ago

2008 ◽  
Vol 4 (2) ◽  
pp. 79-90 ◽  
Author(s):  
◽  
A. Berger ◽  
E. Driesschaert ◽  
H. Goosse ◽  
M. F. Loutre ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Ice Core ◽  
Ice Sheet ◽  
The Tibetan Plateau ◽  
Three Dimension ◽  
Proxy Records ◽  
Asian Summer

Abstract. Deep-sea and ice-core records show that interglacial periods were overall less "warm" before about 420 000 years ago than after, with relatively higher ice volume and lower greenhouse gases concentration. This is particularly the case for the interglacial Marine Isotope Stage 13 which occurred about 500 000 years ago. However, by contrast, the loess and other proxy records from China suggest an exceptionally active East Asian summer monsoon during this interglacial. A three-dimension Earth system Model of Intermediate complexity was used to understand this seeming paradox. The astronomical forcing and the remnant ice sheets present in Eurasia and North America were taken into account in a series of sensitivity experiments. Expectedly, the seasonal contrast is larger and the East Asian summer monsoon is reinforced compared to Pre-Industrial time when Northern Hemisphere summer is at perihelion. Surprisingly, the presence of the Eurasian ice sheet was found to reinforce monsoon, too, through a south-eastwards perturbation planetary wave. The trajectory of this wave is influenced by the Tibetan plateau.

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