St abilization of summer monsoon in middle and lower reaches of the Changjiang river and seasonal transition of East-Asian circulation pattern in early summer

1985 ◽  
Vol 2 (3) ◽  
pp. 376-384
Author(s):  
Chunyu Lin
Keyword(s):  
Summer Monsoon ◽  
East Asian ◽  
Circulation Pattern ◽  
Early Summer ◽  
Changjiang River ◽  
Seasonal Transition ◽  
The Changjiang River

Seasonal precipitation in the south-central Helan Mountain region, China, reconstructed from tree-ring width for the past 224 years

2005 ◽  
Vol 35 (10) ◽  
pp. 2403-2412 ◽  
Author(s):  
Yu Liu ◽  
Qiufang Cai ◽  
Jiangfeng Shi ◽  
M K Hughes ◽  
J E Kutzbach ◽  
...  
Keyword(s):  
20Th Century ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Early Summer ◽  
Climatic Conditions ◽  
Mountain Region ◽  
Asian Summer ◽  
Helan Mountain

Chinese pine (Pinus tabulaeformis Carr.) trees from the Helan Mountain range in central China have been used to reconstruct total January–July precipitation from AD 1775 to 1998. For the calibration period R2adj = 0.52. Narrow rings are associated with below-average precipitation from March through August. Wide rings are produced in years when the East Asian summer monsoon front arrives early. We use local historical writings over the last 300 years about extreme climatic conditions between spring and early summer to verify the extreme years. Most of the extreme dry years could be identified in local historical documents. Another East Asian summer monsoon front related precipitation reconstruction from northern Helan Mountain is also used to verify this reconstruction. They are well correlated from year to year, with a correlation coefficient of 0.52 (N = 218), and the wet or dry extreme events are well matched in many cases. This comparison could indicate a spatial and temporal connection of spring to early summer climatic conditions for the southern to northern portion of the Helan Mountain region. The sustained wet period before the 20th century lasts from the 1850s to the 1890s, and the longest dry period before the 20th century is in the 1830s and 1840s, largely coinciding with a spring–summer drought in Kashmir. Overall, multiyear fluctuations, such as the spectacular large-scale drought of the late 1920s and droughts in the 1830s–1840s and the 1970s, are well captured in this reconstruction, but only the 1970s drought is in the instrumental period. The reconstruction shows increasing variance from the 18th to the late 20th century.

scholarly journals Early Summer Response of the East Asian Summer Monsoon to Atmospheric CO2 Forcing and Subsequent Sea Surface Warming

2016 ◽  
Vol 29 (15) ◽  
pp. 5431-5446 ◽  
Author(s):  
Jinqiang Chen ◽  
Simona Bordoni
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Summer Rainfall ◽  
Early Summer ◽  
Sea Surface ◽  
Atmospheric Co2 ◽  
Asian Summer ◽  
Co2 Forcing

Abstract The early summer regional climate change of the East Asian summer monsoon (EASM) is investigated in the phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive. In the greenhouse gas–forced scenario, reduction of radiative cooling and increase in continental surface temperature occur much more rapidly than changes in sea surface temperatures (SSTs). Without changes in SSTs, the early summer rainfall in the monsoon region decreases (increases) over ocean (land) in most models. On longer time scales, as SSTs increase, rainfall changes are opposite. The total response to atmospheric CO2 forcing and subsequent SST warming is a large (modest) increase in rainfall over ocean (land) in the EASM region. Dynamic changes, in spite of significant contributions from the thermodynamic component, play an important role in setting up the spatial pattern of precipitation changes. Early summer rainfall anomalies over east China are a direct consequence of local land–sea contrast, while changes in the large-scale oceanic rainfall band are closely associated with the displacement of the larger-scale North Pacific subtropical high (NPSH). Ad hoc numerical simulations with the AM2.1 general circulation model show that topography and SST patterns play an important role in early summer rainfall changes in the EASM region.

Effects of the Tibetan Plateau on East Asian Summer Monsoon via Weakened Transient Eddies

2020 ◽  
Author(s):  
Qiaoling Ren ◽  
Song Yang ◽  
Xinwen Jiang ◽  
Yang Zhang ◽  
Zhenning Li
Keyword(s):  
East Asia ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Early Summer ◽  
The Tibetan Plateau ◽  
Rain Belt ◽  
Westerly Jet ◽  
Asian Summer

<p>Previous studies have revealed that the Tibetan Plateau (TP) can weaken the high-frequency and low-frequency transient eddies (TE) transported along the westerly jet. Here the effects of TP on East Asian summer monsoon via weakened TE are investigated based on the simulations by the NCAR Community Earth System Model, in which a nudging method is used to amplify the TP’s inhibition of TE without changing the steady dynamic and thermodynamic effects of TP. Results reveal that the weakened TE by TP weaken the East Asian westerly jet (EAWJ) and shift the jet southward via transient vorticity flux. The southward EAWJ accompanied with reduced poleward transport of moisture by TE results in less rainfall in northern East Asia but more rainfall in southern East Asia, particularly in early summer when the EAWJ is stably located over the TP and the meridional gradient of water vapor is large. Furthermore, the anomalous precipitation can move the EAWJ further southward through the anomalous diabatic heating in early summer, forming a positive feedback. Therefore, the TP’s inhibition of TE can shift the East Asian rain belt southward, different from the TP’s steady forcing which favors a poleward shift of the rain belt. It is also demonstrated that the atmospheric internal variability can lead to the south-flood-north-drought pattern of summer rainfall change over East Asia, indicating the important role of TE in East Asian summer monsoon.</p>

MODERN SEDIMENTATION RATE OF THE SUBMARINE DELTA OF THE CHANGJIANG RIVER

2010 ◽  
Vol 30 (3) ◽  
pp. 1-6 ◽  
Author(s):  
Andong WANG ◽  
Shaoming PAN ◽  
Yongzhan ZHANG ◽  
Zhiyong LIU
Keyword(s):  
Sedimentation Rate ◽  
Changjiang River ◽  
The Changjiang River

scholarly journals Tectonic and climatic drivers of Asian monsoon evolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
James R. Thomson ◽  
Philip B. Holden ◽  
Pallavi Anand ◽  
Neil R. Edwards ◽  
Cécile A. Porchier ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Asian Monsoon ◽  
Monsoon Rainfall ◽  
East Asian Monsoon ◽  
East Asian ◽  
Meridional Overturning Circulation ◽  
Great Debate ◽  
Climatic Drivers ◽  
Meridional Overturning

AbstractAsian Monsoon rainfall supports the livelihood of billions of people, yet the relative importance of different drivers remains an issue of great debate. Here, we present 30 million-year model-based reconstructions of Indian summer monsoon and South East Asian monsoon rainfall at millennial resolution. We show that precession is the dominant direct driver of orbital variability, although variability on obliquity timescales is driven through the ice sheets. Orographic development dominated the evolution of the South East Asian monsoon, but Indian summer monsoon evolution involved a complex mix of contributions from orography (39%), precession (25%), atmospheric CO2 (21%), ice-sheet state (5%) and ocean gateways (5%). Prior to 15 Ma, the Indian summer monsoon was broadly stable, albeit with substantial orbital variability. From 15 Ma to 5 Ma, strengthening was driven by a combination of orography and glaciation, while closure of the Panama gateway provided the prerequisite for the modern Indian summer monsoon state through a strengthened Atlantic meridional overturning circulation.

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